Journal articles on the topic 'Player retention mechanics'

The purpose of video game tutorials is to help players easily understand new game mechanics and thereby facilitate chances of early engagement with the main contents of one’s game. The mobile game market (i.e., phones and tablets) faces important retention issues caused by a high number of players who abandon games permanently within 24 h of downloading them. A laboratory experiment with 40 players tested how tutorial presence and player expertise impact on users’ psychophysiological states and continuous-use intentions (CUIs). The results suggest that in a simple game context, tutorials have a positive impact on non-expert players’ perceived state of flow and have no effect on expert players’ perceived flow. The results also suggest that flow has a positive impact on CUIs for both experts and non-experts. The theoretical contributions and managerial implications of these results are discussed.

Fibrosis is characterized by excessive accumulation of collagen and other extracellular matrix (ECM) components, and this process has been likened to aberrant wound healing. The early phases of wound healing involve the formation of a provisional ECM containing fibrin, fibrinogen, and fibronectin. Fibroblasts occupy this matrix and proliferate in response to activators elaborated by leukocytes that have migrated into the wound and are retained by the ECM. This coincides with the appearance of the myofibroblast, a specialized form of fibroblast whose differentiation is primarily driven by cytokines, such as transforming growth factor-β (TGF-β), and by mechanical tension. When these signals are reduced, as when TGF-β secretion is reduced, or as in scar shrinkage, myofibroblasts undergo apoptosis, resulting in a collagen-rich, cell-poor scar. Retention of myofibroblasts in fibrosis has been described as the result of imbalanced cytokine signaling, especially with respect to levels of activated TGF-β. ECM components can regulate myofibroblast persistence directly, since this phenotype is dependent on extracellular hyaluronan, tenascin-C, and the fibronectin splice variant containing the “extra domain A,” and also, indirectly, through retention of TGF-β-secreting cells such as eosinophils. Thus the ECM is actively involved in both cellular and extracellular events that lead to fibrosis. Targeting components of the ECM as cells respond to injury and inflammatory stimuli holds promise as a means to avoid development of fibrosis and direct the wound-healing process toward reestablishment of a healthy equilibrium.

The purpose of this study was to assess the clinical performance of bonded composite (Excite/Tetric Ceram - Vivadent) versus a resin-modified glass ionomer cement (Vitremer - 3M) for restoring non-carious cervical lesions. A total of 70 restorations (thirty-five per material) were placed in 30 patients, 18-50 aged, by one operator. Rubber dam was employed in all cases, lesions were pumiced, enamel margins were not beveled, and no mechanical retention was placed. The restorations were directly assessed by two independent evaluators using modified-USPHS criteria for six clinical categories. The ratings for clinical acceptability restorations (alfa plus bravo) were as follows (Tetric Ceram/Vitremer): retention (86%/100%), marginal integrity (100%/100%), marginal discoloration (100%/100%), wear (97%/100%), postoperative sensitivity (100%/100%) and recurrent caries (100%/100%). Statistical analysis was completed with Fisher's exact or Pearson Chi-square tests at a significance level of 5% (P<0.05). Results showed that almost all restorations were clinically satisfactory with no significant differences between materials groups. Five restorations of Excite/Tetric Ceram failed. No restorations of Vitremer have yet failed.

In recent years, the inorganic nanoparticles played an important role in the membrane technology due to their special properties, most notably being the hydrophilicity/hydrophobicity modification of the active surface of the membrane. In this paper, the polymer used for membrane manufacturing was polysulfone (PSf) via phase-inversion method. The composite PSf membranes were prepared by blending zinc oxide (ZnO), titanium dioxide (TiO2) nanoparticles and ZnO/TiO2 nanohybrid with three concentrations. Retention of Congo red dye, distilled water permeability, relative flux and relative flux reduction were tested in order to study the effects of the nanoparticles in the membrane matrix. SEM, EDX, porosity, roughness, contact angle, tensile strength and elongation measurement were conducted in this article, also. Compared with control PSf, ZnO/PSf and TiO2/PSf membranes, the experimental results indicated that the ZnO/TiO2/PSf nanohybrid membrane presents the best overall properties, including permeability, retention, and antifouling ability. ZnO/TiO2/PSf membrane exhibits a percentage increase in permeability of 254% and retention of 64.58 % relative to that of the control PSf membrane.

This controlled clinical trial evaluated the 2-year clinical performance of a one-bottle etch-and-rinse adhesive and resin composite system (Excite/Tetric Ceram) compared to a resin-modified glass ionomer cement (RMGIC) (Vitremer/3M) in non-carious cervical lesions. Seventy cervical restorations (35 resin composite - RC- restorations and 35 RMGIC restorations) were placed by a single operator in 30 patients under rubber dam isolation without mechanical preparation. All restorations were evaluated blindly by 2 independent examiners using the modified USPHS criteria at baseline, and after 6, 12 and 24 months. Data were analyzed statistically by Fisher's exact and McNemar tests. After 2 years, 59 out of 70 restorations were evaluated. As much as 78.8% retention rate was recorded for RC restorations, while 100% retention was obtained for RMGIC restorations. Fisher's exact test showed significant differences (p=0.011) for retention. However, there were no significant differences for marginal integrity, marginal discoloration, anatomic form and secondary caries between the RC and RMGIC restorations. The McNemar test detected significant differences for Excite/TC between baseline and the 2-year recall for retention (p=0.02), marginal integrity (p=0.002) and anatomic form (p=0.04). Therefore, the one-bottle etch-and-rinse bonding system/resin composite showed an inferior clinical performance compared to the RMGIC.

Mr. M. was a 77-year-old decisionally incapacitated long-term nursing home resident with chronic schizophrenia who was admitted to the hospital with a bacterial pneumonia. His past medical history was notable for deteriorating functional status over the past 2-3 years, urinary retention requiring chronic indwelling bladder catheterization, and two recent hospitalizations for urinary tract infections leading to sepsis. He developed respiratory failure soon after admission and was intubated and placed on mechanical ventilation. Follow-up studies suggested worsening pneumonia and acute respiratory distress syndrome (ARDS), as well as worsening kidney function.

A novel blend of membranes made of Nafion® and poly(vinylpyrrolidone) (PVP) was prepared and characterized to investigate its applicability in proton exchange membrane fuel cells (PEMFCs). In addition to being effectively proton conductive, the membranes exhibited better mechanical strength, chemical stability, and adequate water retention ability, as well as ion exchange capacity comparable to that of cast Nafion® membrane. The data obtained from an electrochemical impedance spectroscopy (EIS) fitting of the fuel cells revealed the membrane electrode assemblies (MEAs) made of 0.5 wt.% PVP/Nafion® had lower ohmic and charge transfer resistance compared with that of the Nafion® membrane. The intermolecular interactions and morphology of these membranes were assessed using Fourier-transform infrared spectroscopy and field-emission scanning electron microscopy. The results of the performance curve indicate that the introduction of PVP as a modifier played a vital role in improving membrane performance. Accordingly, this solution-casted polymer electrolyte membrane with suitable PVP content offers a simple way to improve electrochemical, mechanical, and chemical properties, and thereby promises the prospect of use in low-temperature PEMFCs.

Abstract Objective Screw loosening in fracture fixation poses a clinical risk which may lead to implant failure, particularly in poor bone quality. The objective of this study was to examine the effectiveness of a novel screw retention technology (SRT) for increased screw purchase in a large animal metatarsal fracture model. Study Design This was a biomechanical, radiographic, and histological study utilizing an ovine metatarsal fracture model. Twenty-four sheep metatarsi underwent 3-mm ostectomies and were repaired with a nine-hole plate and 3.5-mm screws placed in oversized 3.5-mm holes to simulate worst case revision surgeries (i.e. no initial screw thread bone contact). Sheep were sacrificed at 3, 6 or 12 weeks (n = 6 each) post-operation. Post-sacrifice, each surgically implanted screw underwent either destructive mechanical testing or histomorphometric analyses. Results Treated metatarsi showed improved screw retention and normal fracture healing. Significant improvement in breakout strength and pullout strength of screws treated with the SRT were found as a function of healing time. Histologically, bone ingrowth at the screw interface was also shown to significantly increase with healing time. Improvements in fracture healing, indicated by an increase in bone fraction and decrease in void space at the osteotomy, were also observed with healing time. Conclusion The results demonstrate the effectiveness of the SRT as a method for improved screw retention in a rescue-screw type scenario.

We aimed to assess the biological and mechanical-technical complications and survival rate of implants of full-arch metal-ceramic prostheses, during five years of follow-up. 558 implants (of three different brands) retaining 80 full-arch metal-ceramic prostheses were placed in 65 patients, all of whom were examined annually for biological and mechanical-technical complications during the five years of follow-up. Descriptive statistics and univariate logistic regression were calculated. The cumulative survival rate of the implants was 99.8%, and 98.8% prosthesis-based. Mucositis was the most frequent of the biological complications and peri-implantitis was recorded as 13.8% at restoration-level, 16.9% at patient level and 2.0% at implant level. An implant length greater than 10 mm was shown to be a protective factor against biological complications. The mechanical-technical complications were associated with implant diameter, abutment/implant connection and retention system. Loss of screw access filling was the most frequent prosthetic complication, followed by the fracture of the porcelain. Full-arch metal-ceramic prostheses show a high prevalence of implant and prosthesis survival, with few biological and mechanical-technical complications.

SUMMARY Purpose The purpose of this study was to comparatively assess the seven-year clinical performance of a one-bottle etch-and-rinse adhesive with resin composite (RC) and resin-modified glass ionomer (RMGI) restorations in noncarious cervical lesions. Methods and Materials One operator placed 70 restorations (35 restorations in each group) in 30 patients under rubber dam isolation without mechanical preparation. The restorations were directly assessed by two independent examiners, using modified US Public Health Service criteria at baseline and 6, 12, 24, 60, and 84 months. The obtained data were tabulated and statistically analyzed using the Fisher and McNemar tests. A difference was significant if p&lt;0.05. Results Twenty patients were available for recall after seven years (66.6%), and 25 RC and 26 RMGI restorations out of 70 restorations were evaluated. Excellent agreement was registered for all criteria between examiners (κ≥0.85). Alfa and bravo scores were classified as clinically acceptable. The McNemar test detected significant differences within RC restorations between baseline and seven-year evaluations for anatomic form, marginal integrity, and retention (p&lt;0.05). For RMGI restorations, a significant difference was identified for marginal integrity (p&lt;0.05). As to material comparison, the Fisher exact showed a better retention performance for RMGI restorations than for RC restorations (p&lt;0.05). Twelve composite restorations were dislodged (52.0% retention) and three ionomer restorations were lost (88.5% retention). The cumulative success rate for RC and RMGI was 30% and 58.1%, respectively. Conclusions After seven years of service, the clinical performance of RMGI restorations was superior to that of the adhesive system/resin composite restorations in this study.

The remodeling of irradiated bone re-implant placed into simultaneously irradiated bed was studied by scintigraphy method using 99Tc-labeled drug (TcLD) (perfoteh). The data obtained were compared with data of radiologic control. The study included 11 patients with osteogenic sarcoma who were operated on after chemo -radiotherapy course. The peculiarities of operation were as follows. Resected bone with tumor was irradiated by single 60 G dose, after that the bone was re-implanted. It was revealed that 1 month postoperatively TcLD retention in contact zone of bone fragments was 2-2.5 times higher as compared with the symmetric zone of healthy bone. Remodeling peak was observed 1.5-2 months after operation. Over that interval TcLD retention decreased gradually and by 18 months the contact zone was not detected on scintigrams. According to the data of radiologic control the peak of remodeling took place at 6-8 months after operation. The study showed that irradiated re-implant preserved mechanical stiffness and worked as a biologic prosthesis while substituting the newly formed bone. Scintigraphy is an additional method the earlier assessment of reparative processes in extracorporal irradiated reimplant as compared to the assessment of radiologic control.

AbstractThe viscoelastic properties of wood samples treated with various consolidants [polyethylene glycols (PEGs), lactitol and trehalose, Kauramin, polydimethylsiloxane (PDMS) and trimethoxymethylsilane (MTMS), rosin and polyethylene-L-tartaramide] were evaluated by means of dynamic mechanical analysis (DMA) in order to clarify their effects with regard to the conservation of wood objects. Two softwoods, medium-decayed silver fir (Abies alba) and highly decayed maritime pine (Pinus pinaster), and two differently decayed oak hardwoods (Quercusspp.) were used. In addition, the selected parameters [retention, volume variations and equilibrium moisture content (EMC)] were evaluated to assess the consolidation efficacy. The results showed that in treated wood, both the storage modulus and tanδ depend upon the level of degradation. The impact of the consolidating product was greater in more degraded wood (a higher product amount inside the artefact) compared to well-preserved material, where also wood played a role (also when the products were applied at high concentrations). The values of the different viscoelastic parameters also depend upon the ability of the products to interact with the wood matrix; this characteristic is fundamental to the nature of each consolidant. Lactitol-treated samples showed the highest stiffness increases, whereas those treated with selected PEG combinations and rosin displayed noticeable tanδ increases (high dissipative behaviour).

Background: Local delivery agents (LDA) have the advantage of delivering the antibiotics at high concentrations to the targeted sites. However, the constant flow of gingival crevicular fluids and saliva may restrict their efficacy. Therefore, the drug sustainability and pharmacodynamic properties of any proposed LDA should be evaluated. Methods: Four dental implants were placed unilaterally in the edentulous mandible of six beagle dogs. Peri-implantitis were experimentally induced using silk-ligatures. Each implant was randomly allocated to receive one of the following four treatments: (i) MC (Chitosan-alginate (CA) minocycline), (ii) MP (CA-without minocycline), (iii) PG (Polyacrylate-glycerin minocycline), and (iv) Control (mechanical debridement only). Mechanical therapies and LDAs were administered into the gingival sulcus two times at a 4-week interval. Drug sustainability as well as clinical, radiographical, and immunohistochemical (IHC) analyses were conducted to evaluate the efficacies of treatments. Results: Reduced mean probing depth was observed in all of the test groups after the second delivery. A minimal marginal bone level change was observed during the treatment period (MP (−0.06 ± 0.53 mm) to PG (−0.25 ± 0.42 mm)). The distribution of IHC cell marker analysis of all targeted antibodies ranged from 6.34% to 11.33%. All treatment outcomes between the test groups were comparable. A prolonged retention of LDA was observed from CA microspheres (MC and MP) at both administrations (p < 0.017) and prolonged sustainability of bacteriostatic effect was observed from MC compared to PG after the second administration (p < 0.05). Conclusions: Prolonged retention of CA microspheres was observed and the longer bacteriostatic effect was observed from the MC group. Mechanical debridement with adjunct LDA therapy may impede peri-implantitis progression, however, prolonged drug action did not lead to improved treatment outcome.

Buried parallel pipes are used for storm retention systems. Traditional retention-detention systems have spaced parallel pipes that permit soil columns between pipes. A new design allows for the parallel pipes to be placed side by side in contact with each other. The performance of such a system of bundled high-density polyethylene (HDPE) pipes that is subjected to vertical earth loads is reported. This bundled system consists of parallel HDPE pipes wrapped with a geogrid and a geofabric. The actual loads ranged from shallow cover to vertical loads equivalent to 55 ft (16.8 m) of cover. The embedment soil selected for the research was a silty sand. This soil was selected because its structural qualities are generally considered to be the least acceptable for these types of applications. The soil that typically would be specified is a crushed stone. Therefore, the results from the tests are conservative. Structural performance is reported, and photographs present the pipes in the bundled system during installation and after subjection to earth loads. Load-deflection curves for the pipes in the system are also given.

Clinical studies have demonstrated the regenerative potential of stem cells for cardiac repair over the past decades, but their widespread use is limited by the poor tissue integration and survival obtained. Natural or synthetic hydrogels or microcarriers, used as cell carriers, contribute to resolving, in part, the problems encountered by providing mechanical support for the cells allowing cell retention, survival and tissue integration. Moreover, hydrogels alone also possess mechanical protective properties for the ischemic heart. The combined effect of growth factors with cells and an appropriate scaffold allow a therapeutic effect on myocardial repair. Despite this, the effects obtained with cell therapy remain limited and seem to be equivalent to the effects obtained with extracellular vesicles, key actors in intercellular communication. Extracellular vesicles have cardioprotective effects which, when combined proangiogenic properties with antiapoptotic and anti-inflammatory actions, make it possible to act on all the damages caused by ischemia. The evolution of biomaterial engineering allows us to envisage their association with new major players in cardiac therapy, extracellular vesicles, in order to limit undesirable effects and to envisage a transfer to the clinic. This new therapeutic approach could be associated with the release of growth factors to potentialized the beneficial effect obtained.

SUMMARY Objective: To evaluate the clinical performance of Scotchbond Universal (3M Oral Care) and Prime & Bond Elect (Dentsply Sirona) in the restoration of noncarious cervical lesions (NCCLs). Methods and Materials: This was a randomized controlled clinical trial involving 63 subjects. Two hundred and three NCCLs were restored using Scotchbond Universal and Prime & Bond Elect using both an etch-and-rinse and a self-etch technique. Lesions were notch-shaped NCCLs, and the restorations were placed without any mechanical retention. Restorations were finished immediately after placement and scored with regard to retention, marginal discoloration, marginal adaptation, and secondary caries. Similar assessment of the restorations was performed 18 months after placement. Logistic regression was performed for each outcome separately with a compound symmetric variance-covariance structure assumed to consider a correlation of restorations within subjects. All analyses were conducted using SAS version 9.4 (SAS Inc). Results: One hundred and fifty-eight teeth (77.8% of the restorations placed) in 46 subjects (73% of subjects enrolled) were available for the 18-month follow-up. A statistically significant difference was reached only for the comparison Scotchbond Universal/self-etch (SU_SE) and Prime & Bond Elect/etch-and-rinse (PBE_E&R) groups (p=0.01), where a restoration with SU_SE was 66% less likely to maintain a score of Alpha for marginal discoloration than a restoration performed with PBE_E&R. Conclusions: Scotchbond Universal and Prime & Bond Elect presented acceptable clinical performance after 18 months of clinical service. However, Scotchbond Universal, when applied with a self-etch approach, did demonstrate a relatively high level of marginal discoloration when compared to the other groups.

Temperature fast-responsive and magnetic poly(N-isopropylacrylamide-co-acrylamide) (CMX-MNP-PNIPAm/Fe3O4) hydrogels were developed using carboxymethyl xylan (CMX) as a pore-forming agent and a NaCl solution as the reaction medium, followed by fabricating Fe3O4 nanoparticles in situ within the hydrogel matrix. It was found that NaCl played a role in the phase separation and was used as the electrolyte to shield CMX molecular chains. The obtained hydrogels exhibited a fast, temperature-responsive behavior, and the water retention was less than 15% for 1 min under 60 °C. The prepared hydrogels showed enhanced mechanical properties and magnetic properties due to the presence of Fe3O4 particles. The lower critical solution temperature of the hydrogels was in the range of 35 to 39 °C, which was acquired through adjusting the amount of hydrophilic monomer (AM). The magnetic and thermosensitive hydrogel had the attractive photothermal conversion ability and could be heated to 40 °C within 2 min, and to 69 °C within 7 min under near infrared irradiation.

This article presents an overview of a discussion named ‘Decision Point Dialogues,’ which is intended to explore engineering leadership and other critical issues facing the profession. The inaugural dialogue addressed the question: ‘Will engineers be true global problem solvers?’ Using a format developed by Fred Friendly, the former president of CBS News, the seminar started with a story and a problem. Jackson challenged panelists to respond to issues involving specific people, places, and events. Richard Benson, Virginia Tech’s dean of engineering, believes the issue of retention is more complex. Benson said that half of all engineers leave the profession within five years after graduation, where some switch to medicine, law, or business and others receive promotions to management. However, some fail to maintain their skills in a profession that advances at a furious pace. Governments may direct projects to villages to buy votes rather than to meet community needs. For development to succeed, communities must have a stake in the project.

Background Venous thromboembolism (VTE) is a common and often fatal medical event. VTE management often includes inferior vena cava filter (IVCF) placement when anticoagulation fails or is contraindicated. Controversial indications for IVCF placement include adjunctive treatment for deep vein thrombosis (DVT) without pulmonary embolism (PE) and VTE prophylaxis for high-risk patients (Deyoung and Minocha, 2016; Ho et al., 2019). Numerous device-associated mechanical and medical complications have been described (Ayad et al., 2019) and guidelines recommend early retrieval (Morales et al., 2013). There is limited evidence, however, to guide anticoagulation practices while IVCFs are retained. We aimed to characterize IVCF placement, retrieval, and interim medical management at our institution. Methods Retrospective chart review was performed for all patients who underwent IVCF placement at the University of Virginia Medical Center from January to December 2016. Data were collected from time of IVCF placement until either IVCF removal or 18 months post-placement, whichever occurred first. Indication for IVCF placement, baseline patient characteristics, IVCF complications, anticoagulation regimens, and bleeding and clotting events were identified. Baseline characteristics were recorded for all patients. Patients who did not survive the admission during which the IVCF was placed, underwent IVCF removal prior to discharge, or lacked adequate outpatient records during the period of IVCF retention were excluded from the event analysis cohort. Results IVCFs were placed in 140 patients during the study period (Table 1). A majority of patients were admitted to a surgical service, frequently following trauma (49 patients, 35%). IVCFs were placed for several indications, most commonly diagnosed VTE with a contraindication to anticoagulation (70 patients, 50%) and prophylaxis for high risk of VTE (44 patients, 31%). By the end of the study period, 88 patients (63%) had confirmed IVCF removal while 35 patients (25%) retained the IVCF for a clinical consideration. 33 patients (24%) lacking an adequately documented period of outpatient IVCF retention were excluded from the event analysis. Of the 107 patients included in the event analysis cohort, 76 patients (71%) underwent IVCF removal. Removal occurred >60 days after placement in 82% of these cases and median time to removal was 95 days (Table 2). Outpatient follow up and anticoagulation management varied widely, though 75 patients (70%) received a therapeutic dose anticoagulant during the period of IVCF retention and only 15 patients (14%) were not exposed to either a prophylactic or therapeutic dose anticoagulant. 50 patients (47%) had at least one regimen change. Bleeding and/or clotting events occurred for 15 patients (14%, Table 3). All 8 bleeding events occurred during anticoagulant exposure. Patients were exposed to a therapeutic dose anticoagulant during 4 of the 6 observed major or clinically relevant non-major bleeding events. Of the 12 observed clotting events, 8 occurred in the absence of anticoagulation. Isolated DVT was the most common clotting event (8 events in 7 patients, 7%) and IVCF thrombus was observed in 2 patients (2%). Bleeding and clotting events were observed in patients with a wide range of indications for IVCF placement, including patients whose IVCFs were placed prophylactically. Conclusions The optimal medical management of retained IVCFs is uncertain. This retrospective study characterizes IVCF placement, removal, and interim medical management for a diverse patient population at a single institution. Outpatient follow up varied widely and anticoagulant exposure during IVCF retention was inconsistent. Despite considerable anticoagulant exposure across the cohort, major bleeding events were infrequent. Thrombotic events, often in the absence of anticoagulation and potentially preventable, were more common. Standardization of medical management during IVCF retention would likely benefit this heterogeneous patient population at high risk of both bleeding and thrombotic complications. Ongoing statistical modeling for the study cohort will seek to inform anticoagulant decision making by assessing for associations between anticoagulant exposure and these clinical events. Disclosures No relevant conflicts of interest to declare.

The most frequent mechanical complications of the bar-implant-retained overdentures are loosening of the bar screws and the need to reactivate the retentive clips. This article describes a technique to construct a new maxillary overdenture to a nonretrievable round-profile implant connecting bar with 2 distally placed attachments. The retainer round-profile bar was nonretrievable due to a worn retaining screw head. Attachment transfer analogs are used to transfer the position of the attachments to the master cast. The technique allows the clinician to construct new overdentures without the need for removal of the implant connecting bar. Reduced chairside time, reduced treatment cost, and increased patient satisfaction are the major advantages of the technique.

Inorganic-organic composite membranes were prepared by using partly cesium-substituted silicotungstic acid (CHS-WSiA) and polybenzimidazole (PBI, MRS0810H) for medium temperature polymer electrolyte fuel cells (MT-PEFCs). Cesium hydrogen sulfate (CsHSO4, CHS) and silicotungstic acid (H4SiW12O40, WSiA) were milled to obtain 0.5CHS-0.5WSiA composites by dry and wet mechanical millings. N,Ndimethylacetamide (DMAc) was used as a disperse medium in the preparation of the inorganic solid acids by wet mechanical milling and also a casting agent for fabrication of membrane. Finally, flexible and homogeneous composite membranes with several phosphoric acid doping levels (PADLs) were obtained. The wet mechanical milling using DMAc was found to effectively promote good substitution of H+ ion in WSiA by Cs+ ion of CHS and promoted the formation of smaller grain sizes of composites, compared with dry milling. A high maximum power density of 378 mWcm-2 and a good constant current stability test were obtained from a single cell test using the PBI composite membrane containing 20 wt% of 0.5CHS-0.5WSiA from wet milling and phosphoric acid doping level (PADL) of 8 mol, at 150 °C under an anhydrous condition. Wet milling CHS-WSiA crystallites were highly dispersed in PBI to give homogenized membranes and played a significant role in the enhancemance of acidity by increasing the number of proton sites in the electrolyte membrane. After the addition of CHS-WSiA into PBI membrane, the acid and water retention properties were improved and incorporated as new proton conduction path by adsorbing phosphoric acid in these composite electrolyte membranes. These observations suggest that composite membranes with 8 mol of PADL are good promising PA dopedmembranes with effective electrochemical properties for the medium temperature fuel cells.

Abstract Objectives: To determine the success of bracket retention using an adhesion promoter with and without the additional microabrasion of enamel. Materials and Methods: Fifty-two teeth with severe dental fluorosis were bonded in vivo using a split-mouth design where the enamel surfaces of 26 teeth were microabraded with 50 μm of aluminum silicate for 5 seconds under rubber dam and high volume suction. Thirty-seven percent phosphoric acid was then applied to the enamel, washed and dried, and followed by placement of Scotchbond Multipurpose Plus Bonding Adhesive. Finally, precoated 3M Unitek Victory brackets were placed and light cured. The remaining teeth were bonded using the same protocol but without microabrasion. Results: After 9 months of intraoral service, only one bond failure occurred in the control group where microabrasion was used. Chi-square analysis revealed P = .31, indicating no statistical significance between the two groups. Conclusions: Bonding orthodontic attachments to fluorosed enamel using an adhesion promoter is a viable clinical procedure that does not require the additional micro-mechanical abrasion step.

A review on specific parameter measurements to calculate doses per unit of incorporation according to recommendations of the International Commission of Radiological Protection has been performed for inhaled actinide oxides. Alpha activity distribution of the particles can be obtained by autoradiography analysis using aerosol sampling filters at the work places. This allows us to characterize granulometric parameters of "pure" actinide oxides, but complementary analysis by scanning electron microscopy is needed for complex aerosols. Dissolution parameters with their standard deviation are obtained after rat inhalation exposure, taking into account both mechanical lung clearance and actinide transfer to the blood estimated from bone retention. In vitro experiments suggest that the slow dissolution rate might decrease as a function of time following exposure. Dose calculation software packages have been developed to take into account granulometry and dissolution parameters as well as specific physiological parameters of exposed individuals. In the case of poorly soluble actinide oxides, granulometry and physiology appear as the main parameters controlling dose value, whereas dissolution only alters dose distribution. Validation of these software packages are in progress.Key words: actinide oxides, dosimetry, inhalation.

Well-designed porous structured bimetallic ZnSe/CoSe₂/carbon composite nanofibers with uniformly distributed pores were prepared as anodes for sodium-ion batteries by electrospinning and subsequent simple heat-treatment processes. Size-controlled polystyrene (PS) nanobeads in the electrospinning solution played a key role in the formation and uniform distribution of pores in the nanofiber structure, after the removal of selected PS nanobeads during the heat-treatment process. The porous ZnSe/CoSe₂/C composite nanofibers were able to release severe mechanical stress/strain during discharge–charge cycles, introduce larger contact area between the active materials and the electrolyte, and provide more active sites during cycling. The discharge capacity of porous ZnSe/CoSe2/C composite nanofibers at the 10,000th cycle was 297 mA h g−1, and the capacity retention measured from the second cycle was 81%. The final rate capacities of porous ZnSe/CoSe2/C composite nanofibers were 438, 377, 367, 348, 335, 323, and 303 mA h g−1 at current densities of 0.1, 0.5, 1, 3, 5, 7, and 10 A g−1, respectively. At the higher current densities of 10, 20, and 30 A g−1, the final rate capacities were 310, 222, and 141 mA h g−1, respectively.

Erosion and sediment control practices are implemented during construction activities to mitigate downstream effects, but limited field-performance data exists. Field assessments were conducted to evaluate ditch check installations during highway construction in Tama County, Iowa. Data collection included daily rainfall, topographical surveys of sediment deposition, pre- and post-rain event images, and visual observations. Variations to the standard Iowa Department of Transportation silt fence ditch check installation evaluated as part of this study include: (a) upgrading non-reinforced geotextile to a multi-belted, reinforced geotextile (i.e., SF-M1); (b) installing V-shape, as opposed to linear, while incorporating wire reinforcement to support hydrostatic loads placed on the geotextile, inclusion of a weir to facilitate controlled flow discharge, and offsetting the geotextile entrenchment location to improve ground securement (i.e., SF-M2); and (c) installing the dich check as described for SF-M2 substituting slicing for trenching (i.e., SF-M3). The modified wattle installation (i.e., W-M) incorporated a teepee staking configuration to facilitate ground contact, and an excelsior underlay, secured by sod staples, to minimize wattle undercutting. Results from field experiments indicated that sediment retention rates significantly improved for installations of SF-M2 and SF-M3 when compared with the standard installation and SF-M1 at the 85% confidence level, and served as viable control measures in concentrated flow applications. The W-M installation exhibited a statistically significant improvement in sediment retention over the W-S installation at the 95% confidence level. These findings suggest that ditch check performance is a function of specified practice and of installation methods described within regulatory agency specifications and design guidelines.

The most common technology for the manufacture of metal parts and work pieces is casting. High-tech branches of mechanical engineering require the production of high-quality castings of complex configuration from modern alloys with a given chemical composition and mechanical properties. The analysis of the causes of slag inclusions and ways to prevent them showed that in addition to technological means related to quality preparation of metal before pouring, a significant role is played by quiet continuous pouring of metal and properly designed foundry system, including slag trap. However, the use of the most common foundry systems (braking, throttle, with centrifugal slag traps, rain, siphon) to increase the efficiency of slag retention is associated with increased metal consumption, and as a consequence, leads to an increase in the cost of casting. Conducting experimental research by varying the design of the slag trap leads to an increase in the number of field experiments, given their complexity, limited by great difficulties. On the other hand, computer flow modeling allows to study the influence of slag trap design on the flow rate of the melt at the design stage and significantly reduce the cost of introduction of new castings. In order to reliably capture slag and reduce the speed of movement of the melt in the foundries, which provides a smooth filling of the form with an alloy, but without additional costs of metal, the original design of the ribbed slag catcher is proposed. The results of parametric modeling of the melt flow in the channel of the ribbed slag trap showed a decrease in the flow rate along the cross-sectional height of the slag trap compared to traditional by 0.028 m / s or 14.5%. This allowed to reduce the length of the slag trap to the first feeder. The expected metal savings are 0.26%. The form made using a 3D model of the slag trap showed satisfactory molding ability. But the obtained research results are of a recommendatory nature and require practical verification in the production environment. In addition, by varying parameters such as the height of the ribs, the distance between them, the angle of inclination, we can obtain similar results for different castings of different alloys. Given all this, there is a need for further study of the impact of the design of the slag trap on the efficiency of slag retention.

The concept for the disposal of high-level radioactive waste (HLW) in Switzerland is illustrated in Figure 1: the waste, solidified in a borosilicate glass matrix, is encapsulated in a 25-cm-thick steel canister which has a minimum life expectancy of 1,000 years. After this time, the heat produced by 90Sr and 137Cs will have dissipated and the repository will have adjusted to the host rock ambient temperature of around 60°C.The steel canisters will be placed in horizontal tunnels, 3.7 m in diameter, at a depth of around 1,000 m in the granite of northern Switzerland, and the tunnels then backfilled. The backfill material, an important link in the chain of engineered and natural safety barriers, satisfies both physical/mechanical and chemical requirements. The most important of these are:• Low hydraulic conductivity compared to the host rock;• Good swelling properties to seal construction-caused joints and rock fractures;• Plasticity to absorb rock movements and to distribute pressure homogeneously;• Good retention of radionuclides; and• Stability over a period of at least 106 years.Economic aspects and availability should also be considered: each canister requires 88 tons of backfill material, or of the order of 250,000 metric tons for the planned repository.

This paper focuses on the preparation of boron-containing phenolic resin (BPR)-derived carbon modified three-dimensional (3D) needled carbon fiber reinforced silicon oxycarbide (SiOC) composites through a simple precursor infiltration and pyrolysis process (PIP), and the influence of PIP cycle numbers on the microstructure, mechanical, high-temperature oxidation resistance. The electromagnetic wave (EMW) absorption properties of the composites were investigated for the first time. The pyrolysis temperature played an important role in the structural evolution of the SiOC precursor, as temperatures above 1400 °C would cause phase separation of the SiOC and the formation of silicon carbide (SiC), silica (SiO2), and carbon. The density and compressive strength of the composites increased as the PIP cycle number increased: the value for the sample with 3 PIP cycles was 0.77 g/cm3, 7.18 ± 1.92 MPa in XY direction and 9.01 ± 1.25 MPa in Z direction, respectively. This composite presented excellent high-temperature oxidation resistance and thermal stability properties with weight retention above 95% up to 1000 °C both under air and Ar atmosphere. The minimal reflection loss (RLmin) value and the widest effective absorption bandwidth (EAB) value of as-prepared composites was −24.31 dB and 4.9 GHz under the optimization condition for the sample with 3 PIP cycles. The above results indicate that our BPR-derived carbon modified 3D needled carbon fiber reinforced SiOC composites could be considered as a promising material for practical applications.

Machine tools are highly integrated mechatronic systems consisting of dedicated mechanic design and integrated electrical equipment - in particular drive systems and the CNC-control - to realize the complex relative motion of tool towards work piece. Beside the process related capabilities, like static and dynamic stiffness as well as accuracy behavior and deviation resistance against thermal influence, safety aspects are of major interest. The machine tool enclosure must fulfill multiple requirements like retention capabilities against the moving parts of broken tools, lose work pieces or clamping components. In regular use, the noise emission have to be inhibited at the greatest possible extent by the machine tool enclosure. Nevertheless, the loading door and the moving parts of the workspace envelope are interfaces where noise transmission is harder to be avoided and therefore local noise emissions increase. The aim of the objective investigation is to analyse the noise emission of machine tools to determine the local noise transmission of a machine tool enclosure by using arrays of microphones. By the use of this measuring method, outer surfaces at the front, the side and on the top of the enclosure have been scanned. The local transient acoustic pressures have been recorded using a standard noise source placed on the machine table. In addition, an exemplary manufacturing process has been performed to analyse the frequency dependent location resolved sound emissions.

Abstract Aim This study compared the shear bond strength (SBS) and flexural strength (FS) of repaired interfaces using three techniques of surface preparation and repair of a micro-hybrid composite. Methods and Materials Composite specimens for SBS tests (n=36: diameter=8 mm, thickness=3 mm) for repair were shaped in a metal mold, visible-light cured, and embedded in dental stone. Composite specimens for FS tests (n=36: 2 mm × 2 mm × 12.5 mm) for repair were shaped in a silicone mold. Three different methods of surface preparation were evaluated: Group A (control) specimens were treated by etching with 35% phosphoric acid; Group B specimens were airabraded with 50 μm aluminum oxide at 100 psi; and Group C specimens received two parallel, 1 mm-deep grooves using a #¼.-round bur before being treated by etching with 35% phosphoric acid. After surface treatment, a bonding agent was placed on each specimen, which was then light cured. Repairs were accomplished by adding more composite to the SBS or FS specimens. Specimens were thermocycled 500 times between 5°C and 55°C with 30-second dwell times. All specimens were tested by loading to failure at a rate of 0.5 mm/min using an Instron Universal Testing Machine. Results Mean SBSs in MPa were: Group A=24.5 +4.4, Group B=28.5 +4.3, and Group C=27.0 +2.8. Mean FSs (MPa) were: Group A=60.5 +9.9, Group B=73.9 +13.2 and Group C=81.3 +14.3. For the FS tests, Group B and C were significantly different than Group A, but Group C was not significantly different than group B. For the SBS test, Group B was significantly different than Group A, but Group C was not significantly different. Conclusion Acid-etching alone was not very effective in producing well-bonded composite repairs (only 55% of the FS of normal microhybrid composite). Mechanical retention was more effective (SBS, FS) than acid-etching and as effective (SBS) or more effective (FS) than air-abrasion (p<0.05) for repaired composite specimens. Clinical Significance Either mechanical retention or air abrasion is recommended prior to repairing an existing composite restoration to achieve the highest bond strength. Citation Vivas J, Yaman P, Taylor G. Effect of Different Surface Treatments on the Shear and Flexural Re-bond Strengths of a Micro-hybrid Composite. J Contemp Dent Pract [Internet]. 2009 Sept; 10(5). Available from: http://www. thejcdp.com/journal/view/effectof-differentsurface- treatments-on-the-shear-and-flexural-rebond- st.

Abstract Introduction: malaria is one of the most frequent hematological diseases worldwide. Because the malaria parasite Plasmodium falciparum develops mainly in red blood cells (RBC), splenic retention of infected and uninfected RBC is likely a key player in the variable susceptibility of humans to malaria. Age and ethnicity are important determinants of the manifestations of malaria in Africa (Reyburn JAMA 2005, Dolo Am J Trop Med Hyg 2005; Greenwood Ann Trop Med Parasitol 1987; Torcia PNAS 2008), Asia (Price Am J Trop Med Hyg 2001), and in travelers (Seringe Emerg Infect Dis 2011). We had speculated that variations in the splenic sensing of RBC contribute to the innate protection/susceptibility of infants against distinct forms of severe malaria and to the pathogenesis of chronic malaria (Buffet Curr Opin Hematol 2009; Buffet Blood 2011). Here, we explore the deformability and morphology of circulating RBC in populations living in a malaria-endemic area. Materials and methods: experiments were embedded in an integrated study driven by Institut de Recherche pour le Développement, which aims at the identification of genetic, epidemiologic and anthropologic determinants of susceptibility to malaria. IRB approval was obtained from Institut des Sciences Biomédicales Appliquées, Benin. Clinical and biological data were collected at the beginning of the rainy season from 627 individuals, belonging to 4 different ethnic groups living in sympatry in Atakora, North Benin and included age, gender, ethnicity, body temperature, presence and grade of splenomegaly, rapid diagnostic test for malaria (RDT), thick film and rapid hemoglobin determination with HemoCue©. Venous blood was collected for determination of RBC morphology and deformability. Using microsphiltration, a RBC filtering method that uses microsphere layers to mimic the mechanical retention of RBC in the splenic red pulp (Deplaine Blood 2011) we quantified the ability of a mix of labeled and non-labeled RBCs to squeeze between calibrated slits, results being expressed as retention or enrichment rates (RER) of subject's RBC compared to normal RBC (from a single French O-positive donor) stored in blood bank conditions. Microsphiltration has been adapted to high-throughput experimentation using microplates (Duez AAC 2015). Experiments were performed in a field laboratory established on site; microplates were prepared in Paris and brought to North Benin in luggage with constant care to avoid shocks during transportation. All RBC samples were filtered in triplicate less than 8 hours after blood collection. Up- and downstream samples were brought back to France at 4°C in sealed micro-well plates and analyzed for individual RER calculation in the next 2 weeks by flow cytometry. Results: over 10 days, 262 adults and 249 children were included, 31% Bariba, 17% Gando (genetically related to Bariba), 24% Otamari, 27% Peulhs. Prevalences of splenomegaly, positive RDT, and fever were 13%, 27%, and 2%, respectively. Of 629 blood samples collected, 511 could be analyzed. RER of controls remained stable with time and across 17 microfiltering plates, with a median (IQR) retention rate of 12% (5% - 21%). Ethnicity and age were the only two factors associated with statistically significant differences in RER (figures 1 and 2). Infants (less than 2 year-old) had a more important enrichment than older children and adults (median in 2 years old or less 287%; 3 to 5 years 103%; 6 to 10 years: 64%; more than ten years: 91%; p=0.0161). Peulhs and Otamari also had higher median enrichment rates than Bariba and Gando (RER: 122% and 118%, 75%, 64%, respectively; p=0.0246). Conversely, splenomegaly, gender, positivity of RDT or anemia at the time of sampling were not associated with RER. Discussion: higher averaged enrichment rates in specific ethnic subgroups, namely Peulhs and Otamari, likely result from a more stringent splenic retention, leaving more deformable RBC in circulation. An innate spleen-RBC interaction process was also observed in infants, which is consistent with the higher incidence of severe malarial anemia and splenomegaly observed in this population (Reyburn JAMA 2005; Price Am J Trop Med Hyg 2001). Our results show that innate factors (e.g. ethnicity and age) tend to influence the deformability of RBC, and therefore the phenotypic expression of malaria in Africa. Ongoing experiments aim at deciphering the mechanisms responsible for these differences. Disclosures No relevant conflicts of interest to declare.

Little is reported about the prosthetic aftercare of implant-supported mandibular overdentures regarding the number of implants placed. The purpose of this study was to evaluate the prosthetic aftercare among edentulous patients restored with two vs. four mandibular implant-retained overdentures (MISOD). Forty-six consecutive edentulous patients treated by a new MISOD were retrospectively studied. Twenty-five patients had two-ball attachment MISOD (Group A), and 21 had four-ball attachment MISOD (Group B). The total amount of aftercare visits was recorded, as well as the type of treatments required (pressure sore spots relief, attachment liner replacement due to loss of retention, and metal ball attachment replacement due to wear). The mean follow-up duration was 93 ± 57 months (range 9–246 months). None of the implants was lost. There were significantly more visits for pressure sore spots relief in Group A vs. Group B (6.2 ± 2 in group A and 4.09 ± 1.54 in group B, p < 0.0001). Differences in the other two tested parameters (number of visits for liner replacement (2.3 ± 1.84 in group A and 2.4 ± 1.63 in group B) and attachment replacement (2.36 ± 1.85 in group A vs. 2.48 ± 1.63 in group B) yielded a non-significant outcome (p = 0.814 for liner replacement and p = 1.000 for attachment replacement). The use of four-ball attachments in MISOD was more beneficial than two-ball attachments with regards to the aftercare of pressure sore spots. The number of implants did not influence the mechanical wear.

SUMMARY Objective Repairing composite restorations may be a more conservative treatment than replacing the entire restoration. The objective of this in vitro study was to determine the best repair method by measuring flexural, diametral tensile, and shear bond strength of repaired composites in which the surfaces were treated with chemical primers (Add & Bond or Silane Bond Enhancer), a bonding agent (Optibond Solo Plus [OBSP]), or mechanical retention with a bonding agent. Methods Filtek Supreme Ultra shade B1B was placed in special molds to fabricate specimens that served to test the flexural, diametral tensile, or shear strength of the inherent resin substrate. The same molds were modified to make specimens for testing repair strength of the resin. Repairs were made immediately or after aging in deionized water at 37°C for seven days. All repair sites were finished with coarse Sof-Lex discs to simulate finishing new restorations or partially removing aged restorations. Repair surfaces were treated with one of the following: 1) phosphoric-acid etching and OBSP; 2) Add & Bond; 3) phosphoric-acid etching, Silane Bond Enhancer, and OBSP; or 4) quarter round bur, phosphoric-acid etching, and OBSP. Specimens were placed back in the original molds to fabricate specimens for diametral tensile or flexural testing or in an Ultradent jig to make specimens for shear bond testing. Composite resin in shade B5B was polymerized against the treated surfaces to make repairs. Two negative control groups for the three testing methods consisted of specimens in which repairs were made immediately or after aging without any surface treatments. Controls and experimental repairs were aged (water 37°C, 24 hours) before flexural, diametral tensile, or shear testing in an Instron Universal testing machine at a crosshead speed of 0.5 mm/min. Results Experimental flexural repair strengths ranged from 26.4% to 88.6% of the inherent substrate strength. Diametral tensile repair strengths ranged from 40% to 80% of the inherent substrate strength, and shear bond strength repairs ranged from 56% to 102%. Geometric means were statistically analyzed with two-way analysis of variance on their log-transformed values. Significant differences were determined using Tukey honestly significant difference (p&lt;0.05). Conclusions Depending on the mechanical property being tested, surface treatments produced different results. OBSP produced more consistent results than chemical primers.

Topicality. A survey of the water use system at a state-owned enterprise processing agricultural products revealed the technological processes that cause biofouling of pipelines by colloidal inclusions (mainly phytoplankton conglomerates of blue-green algae). The implementation of measures that can protect existing technological structures against the ingress of significant masses of phytoplankton is an urgent task that can be solved with the help of mechanical filters. The efficiency of previous granulated loading filters depends very much on the properties of the filter loading. When filter loading is made of foamed polystyrene granules of food brands, phytoplankton retention is quite effective due to the physical adsorption of cyanobacteria conglomerates on the surface of these granules. Research results. By applying the semi-empirical model developed in IWPLR of NAAS, the optimal design and technological parameters of the filter with foam polystyrene loading were selected. That enabled to develop the design of a clarifying filter - a phytoplankton retainer for the treatment of circulating water at the enterprise Chervonoslobidsky distillery. In the lower part of the filter the lower drainage system in the form of a false bottom is placed, equipped with hole caps. It provides the source water entry for filtration and discharge of flush water during filter washing. The granules of the filter loading are kept from floating with the false bottom of the upper drainage, which is equipped with return filters - hole caps. Filtered water is collected in the abovefiltering space between the false bottom and the upper part of the filter body, from where it is delivered through a pipeline to the consumers. The application of the developed filter design allows reducing the construction costs and simplifies the filter design, which in turn increases its reliability and overall service life. The practical application of this filter provided the required degree of retention of cyanobacteria cells and conglomerates from the treated water. This filter design differs from the standard with a 1.5 times increased filter loading layer. This enabled to double the duration of a filter cycle and, at the same time, did not increase the volume of flushing water, i.e. operating costs. Conclusions. Based on the results of the developed semi-empirical model, the design and technological parameters of granular filters for recycling of wastewater from the distilleries were determined, which became the basis for developing a new filter design for water purification from cyanobacteria cells and colonies. The high efficiency of the developed design of the clarifying filter - phytoplankton retainer was experimentally proved. The use of the developed filter increases the economic efficiency of the circulating use of the wastewater from Chervonoslobidsky distillery by 1.3 - 1.5 times compared to the market offers of mechanical filters.

Objective: This study evaluated the in vitro bond strength of Class I restorations to dentin, using four restorative systems. Materials and Methods: Ninety-six molars were used, and a Class I cavity was prepared on the occlusal surface. Next, tooth were divided into 4 groups (n=24), Single Bond Universal + Filtek Z350 XT (SFZ); Single Bond Universal + Filtek Bulk Fill (SFB); AdheSE + Tetric N-Ceram (ATC) and AdheSE + Tetric N-Ceram Bulk Fill (ATB).Thus, the teeth were divided into 3 subgroups (n = 8): 1) storage in water for 24h (control); 2) submitted to thermocycling; 3) mechanical loading. After challenges, teeth were cut into beams 0.8mm², being 3 to 4 sticks per tooth. Then, the specimens were submitted to microtensile testing (μTBS). The data were submitted to Kruskal Wallis and Dunn tests for multiple comparisons, with a significance level of 5%. Results: No significant differences were observed between the restorative systems after thermal cycling challenge (p> 0.05). However, the SFZ group presented the highest μTBS values, with a statistical difference when compared to the ATC, SFB and ATB groups after mechanical loading (p> 0.05). Conclusion: The dentin bond strength of low-shrinkage composite resin restorations was negatively influenced by mechanical loading in class I cavities. Descriptors: Dental Materials; Permanent Teeth; Resin Composite; Restoration; Substrate Cycling. References Bedran-Russo A, Leme-Kraus AA, Vidal CMP, Teixeira EC. An overview of dental adhesive systems and the dynamic tooth-adhesive interface. Dent Clin N Am. 2017; 61:713-31. Rosatto CM, Bicalho AA, Veríssimo C, Bragança GF, Rodrigues MP, Tantbirojn D, et al. Mechanical properties, shrinkage stress, cuspal strain and fracture resistance of molars restored with bulk-fill composites and incremental filling technique. J Dent. 2015;43:1519-28. Ilie N, Bucuta S, Draenert M. Bulk-fill resin-based composites: an in vitro assessment of their mechanical performance. Oper Dent. 2013;38:18-25. Caixeta RV, Guiraldo RD, Kaneshima EN, Barbosa AS, Picolotto CP, Lima AE, et al. Push-out bond strength of restorations with bulk-fill, flow, and conventional resin composites. ScientificWorldJournal 2015; 2015:452976. Amaral FL, Colucci V, Palma-Dibb RG, Corona SA. Assessment of in vitro methods used to promote adhesive interface degradation: a critical review. J Esthet Restor Dent. 2007;19:340-53. Daneshkazemi A, Davari A, Akbari MJ, Davoudi A, Badrian H. Effects of thermal and mechanical load cycling on the dentin microtensile bond strength of Single Bond-2. J Int Oral Health 2015;7:9-13. Poptani B, Gohil KS, Ganjiwale J, Shukla M.Microtensile dentin bond strength of fifth with five seventh-generation dentin-bonding agents after thermocycling: An in vitro study. Contemp Clin Dent. 2012;3(Suppl 2):S167-71. Heintze SD, Monreal D, Peschke A. Marginal quality of Class II composite restorations placed in bulk compared to an incremental technique: Evaluation with SEM and Stereomicroscope. J Adhes Dent. 2015;17:147-54. Soares CJ, Pizi EC, Fonseca RB, Martins LR. Influence of root embedment material and periodontal ligament simulation on fracture resistance tests. Braz Oral Res. 2005;19:11-6. Aguiar TR, André CB, Correr-Sobrinho L, Arrais CA, Ambrosano GM, Giannini M. Effect of storage times and mechanical load cycling on dentin bond strength of conventional and self-adhesive resin luting cements. J Prosthet Dent. 2014;111:404-10. Assunção WG, Jorge JR, Dos Santos PH, Barão VA, Gomes EA, Delben JA. The effect of mechanical cycling and different misfit levels on Vicker's microhardness of retention screws for single implant-supported prostheses J Prosthodont. 2011;20:523-27. De Munck J, Luehrs AK, Poitevin A, Van Ende A, Van Meerbeek B. Fracture toughness versus micro-tensile bond strength testing of adhesive-dentin interfaces. Dent Mater. 2013;29:635-44. Armstrong S, Breschi L, Özcan M, Pfefferkorn F, Ferrari M, Van Meerbeek B. Academy of Dental Materials guidance on in vitro testing of dental composite bonding effectiveness to dentin/enamel using micro-tensile bond strength (μTBS) approach. Dent Mater. 2017;33:133-43. Tjäderhane L, Nascimento FD, Breschi L, Mazzoni A, Tersariol IL, Geraldeli S et al. Strategies to prevent hydrolytic degradation of the hybrid layer- A review. Dent Mater. 2013; 29:999-11. Taneja S, Kumar P, Kumar A. Comparative evaluation of the microtensile bond strength of bulk fill and low shrinkage composite for different depths of Class II cavities with the cervical margin in cementum: An in vitro study. J Conserv Dent. 2016;19:532-35. Campos EA, Ardu S, Lefever D, Jassé FF, Bortolotto T, Krejci iI. Marginal adaptation of class II cavities restored with bulk-fill composites. J Dent. 2014;42;575-81. Mandava J, Vegesna DP, Ravi R, Boddeda MR, Uppalapati LV, Ghazanfaruddin MD. Microtensile bond strength of bulk-fill restorative composites to dentin. J Clin Exp Dent. 2017;9:e1023-28. Costa T, Rezende M, Sakamoto A, Bittencourt B, Dalzochio P, Loguercio AD, et al. Influence of adhesive type and placement technique on postoperative sensitivity in posterior composite restorations. Oper Dent. 2017;42:143-54. Jayaseel A, Niranjan N, Pamidi H, Suryakanth MB. Comparative evaluation of shear bond strength of universal dental adhesives - An in vitro study. J Clin Exp Dent. 20171;9:e892-e96. Silame FDJ, Geraldeli GP, Sinhoreti MAC, Pires-de-Souza FCP, Roulet JF, Geraldeli S. Dentin µTBS and hardness of bulk-fill and conventional composites placed in a box-shaped cavity preparation. J Adhes Dent. 2017;19:395-400. Han SH, Park SH. Comparison of internal adaptation in class II bulk-fill composite restorations using micro-CT. Oper Dent. 2017;42:203-14. Al-Harbi F, Kaisarly D, Michna A, ArRejaie A, Bader D, El Gezawi M. Cervical interfacial bonding effectiveness of class II bulk versus incremental fill resin composite restorations Oper Dent. 2015;40:622-35. Amaral FL, Colucci V, Palma-Dibb RG, Corona SA. Assessment of in vitro methods used to promote adhesive interface degradation: a critical review J Esthet Restor Dent. 2007; 19:340-53. Lezaja Zebic M, Dzeletovic B, Miletic V. Microtensile bond strength of universal adhesives to flat versus Class I cavity dentin with pulpal pressure simulation J Esthet Restor Dent. 2018;30:240-48. Yazici AR, Antonson SA, Kutuk ZB, Ergin E. Thirty-six-month clinical comparison of bulk fill and nanofill composite restorations. Oper Dent. 2017;42:478-85.

Summary This paper describes the design procedures that led to favorable incremental oil production and reduced water production during 12 years of successful polymer flooding in the Daqing oil field. Special emphasis is placed on some new design factors that were found to be important on the basis of extensive experience with polymer flooding. These factors include (1) recognizing when profile modification is needed before polymer injection and when zone isolation is of value during polymer injection, (2) establishing the optimum polymer formulations and injection rates, and (3) time-dependent variation of the molecular weight of the polymer used in the injected slugs. For some Daqing wells, oil recovery can be enhanced by 2 to 4% of original oil in place (OOIP) with profile modification before polymer injection. For some Daqing wells with significant permeability differential between layers and no crossflow, injecting polymer solutions separately into different layers improved flow profiles, reservoir sweep efficiency, and injection rates, and it reduced the water cut in production wells. Experience over time revealed that larger polymer-bank sizes are preferred. Bank sizes grew from 240-380 mg/L·PV during the initial pilots to 640 to 700 mg/L·PV in the most recent large-scale industrial sites [pore volume (PV)]. Economics and injectivity behavior can favor changing the polymer molecular weight and polymer concentration during the course of injecting the polymer slug. Polymers with molecular weights from 12 to 35 million Daltons were designed and supplied to meet the requirements for different reservoir geological conditions. The optimum polymer-injection volume varied around 0.7 PV, depending on the water cut in the different flooding units. The average polymer concentration was designed approximately 1000 mg/L, but for an individual injection station, it could be 2000 mg/L or more. At Daqing, the injection rates should be less than 0.14-0.20 PV/year, depending on well spacing. Introduction Many elements have long been recognized as important during the design of a polymer flood (Li and Niu 2002; Jewett and Schurz 1970; Sorbie 1991; Vela et al. 1976; Taber et al. 1997; Maitin 1992; Koning et al. 1988; Wang et al. 1995; Wang and Qian 2002; Wang et al. 2008). This paper spells out some of those elements, using examples from the Daqing oil field. The Daqing oil field is located in northeast China and is a large river-delta/lacustrine-facies, multilayer, heterogeneous sandstone in an inland basin. The reservoir is buried at a depth of approximately 1000 m, with a temperature of 45°C. The main formation under polymer flood (i.e., the Saertu formation) has a net thickness ranging from from 2.3 to 11.6 m with an average of 6.1 m. The average air permeability is 1.1 µm2, and the Dykstra-Parsons permeability coefficient averages 0.7. Oil viscosity at reservoir temperature averages approximately 9 mPa·s, and the total salinity of the formation water varies from 3000 to 7000 mg/L. The field was discovered in 1959, and a waterflood was initiated in 1960. The world's largest polymer flood was implemented at Daqing, beginning in December 1995. By 2007, 22.3% of total production from the Daqing oil field was attributed to polymer flooding. Polymer flooding should boost the ultimate recovery for the field to more than 50% OOIP--10 to 12% OOIP more than from waterflooding. At the end of 2007, oil production from polymer flooding at the Daqing oil field was more than 11.6 million m3 (73 million bbl) per year (sustained for 6 years). The polymers used at Daqing are high-molecular-weight partially hydrolyzed polyacrylamides (HPAMs). During design of a polymer flood, critical reservoir factors that traditionally receive consideration are the reservoir lithology, stratigraphy, important heterogeneities (such as fractures), distribution of remaining oil, well pattern, and well distance. Critical polymer properties include cost-effectiveness (e.g., cost per unit of viscosity), resistance to degradation (mechanical or shear, oxidative, thermal, microbial), tolerance of reservoir salinity and hardness, retention by rock, inaccessible pore volume, permeability dependence of performance, rheology, and compatibility with other chemicals that might be used. Issues long recognized as important for polymer-bank design include bank size (volume), polymer concentration and salinity (affecting bank viscosity and mobility), and whether (and how) to grade polymer concentrations in the chase water. This paper describes the design procedures that led to favorable incremental oil production and reduced water production during 12 years of successful polymer flooding in the Daqing oil field.

ABSTRACTThe bulk CMOS devices continue as the dominant player for at least another couple of technology nodes. This drives the increasingly contradicting requirements for the channel, source/drain extension, and heavily doped source/drain doping profiles. To analyze and optimize the transistors, it is becoming necessary to combine a number of effects that have been treated as decoupled so far. The temperature gradients, combined with stress engineering techniques such as embedded SiGe and Si:C source/drain and stress memorization technique, create non-uniform stress distributions determined by the layout patterns. The interaction of implant-induced damage with dopants, stress, and defect traps shapes up the dopant activation, retention of useful stress, and junction leakage. This work reviews recent trends in modeling these effects using continuum and kinetic Monte Carlo methods.

IntroductionIn his now-seminal book, Pilgrim in the Microworld (1983), David Sudnow details his process of learning to play the game Breakout on the Atari 2600. Sudnow develops an account of his graduation from a novice (having never played a videogame prior, and middle-aged at time of writing) to being able to fluidly perform the various configurative processes involved in an acclimated Breakout player’s repertoire.Sudnow’s account of videogame skill-development is not at odds with common-sense views on the matter: people become competent at videogames by playing them—we get used to how controllers work and feel, and to the timings of the game and those required of our bodies, through exposure. We learn by playing, failing, repeating, and ultimately internalising the game’s rhythms—allowing us to perform requisite actions. While he does not put it in as many words, Sudnow’s account affords parity to various human and nonhuman stakeholders involved in videogame-play: technical, temporal, and corporeal. Essentially, his point is that intertwined technical systems like software and human-interface devices—with their respective temporal rhythms, which coalesce and conflict with those of the human player—require management to play skilfully.The perspective Sudnow develops here is no doubt important, but modes of building competency cannot be strictly fixed around a player-videogame relationship; a relatively noncontroversial view in game studies. Videogame scholars have shown that there is currency in understanding how competencies in gameplay arise from engaging with ancillary objects beyond the thresholds of player-game relations; the literature to date casting a long shadow across a broad spectrum of materials and practices. Pursuing this thread, this article addresses the enterprise (and conceptualisation) of ‘skill building’ in videogames (taken as the ability to ‘beat games’ or cultivate the various competencies to do so) via the invocation of peripheral objects or practices. More precisely, this article develops the perspective that we need to attend to the impacts of ancillary objects on play—positioned as hybrid assemblage, as described in the work of writers like Sudnow. In doing so, I first survey how the intervention of peripheral game material has been researched and theorised in game studies, suggesting that many accounts deal too simply with how players build skill through these means—eliding the fact that play works as an engine of many moving parts. We do not simply become ‘better’ at videogames by engaging peripheral material. Furthering this view, I visit recent literature broadly associated with disciplines like post-phenomenology, which handles the hybridity of play and its extension across bodies, game systems, and other gaming material—attending to how skill building occurs; that is, through the recalibration of perceptual faculties operating in the bodily and temporal dimensions of videogame play. We become ‘better’ at videogames by drawing on peripheral gaming material to augment how we negotiate the rhythms of play.Following on from this, I conclude by mobilising post-phenomenological thinking to further consider skill-building through peripheral material, showing how such approaches can generate insights into important and emerging areas of this practice. Following recent games research, such as the work of James Ash, I adopt Bernard Stiegler’s formulation of technicity—pointing toward the conditioning of play through ancillary gaming objects: focusing particularly on the relationship between game skill, game guides, and embodied processes of memory and perception.In short, this article considers videogame skill-building, through means beyond the game, as a significant recalibration of embodied, temporal, and technical entanglements involved in play. Building Skill: From Guides to BodiesThere is a handsome literature that has sought to conceptualise the influence of ancillary game material, which can be traced to earlier theories of media convergence (Jenkins). More incisive accounts (pointing directly at game-skill) have been developed since, through theoretical rubrics such as paratext and metagaming. A point of congruence is the theme of relation: the idea that the locus of understanding and meaning can be specified through things outside the game. For scholars like Mia Consalvo (who popularised the notion of paratext in game studies), paratexts are a central motor in play. As Consalvo suggests, paratexts are quite often primed to condition how we do things in and around videogames; there is a great instructive potential in material like walkthrough guides, gaming magazines and cheating devices. Subsequent work has since made productive use of the concept to investigate game-skill and peripheral material and practice. Worth noting is Chris Paul’s research on World of Warcraft (WoW). Paul suggests that players disseminate high-level strategies through a practice known as ‘Theorycraft’ in the game’s community: one involving the use of paratextual statistics applications to optimise play—the results then disseminated across Web-forums (see also: Nardi).Metagaming (Salen and Zimmerman 482) is another concept that is often used to position the various extrinsic objects or practices installed in play—a concept deployed by scholars to conceptualise skill building through both games and the things at their thresholds (Donaldson). Moreover, the ability to negotiate out-of-game material has been positioned as a form of skill in its own right (see also: Donaldson). Becoming familiar with paratextual resources and being able to parse this information could then constitute skill-building. Ancillary gaming objects are important, and as some have argued, central in gaming culture (Consalvo). However, critical areas are left unexamined with respect to skill-building, because scholars often fail to place paratexts or metagaming in the contexts in which they operate; that is, amongst the complex technical, embodied and temporal conjunctures of play—such as those described by Sudnow. Conceptually, much of what Sudnow says in Microworld undergirds the post-human, object-oriented, or post-phenomenological literature that has begun to populate game studies (and indeed media studies more broadly). This materially-inflected writing takes seriously the fact that technical objects (like videogames) and human subjects are caught up in the rhythms of each other; digital media exists “as a mode or cluster of operations in consort with matter”, as Anna Munster tells us (330).To return to videogames, Patrick Crogan and Helen Kennedy argue that gameplay is about a “technicity” between human and nonhuman things, irreducible to any sole actor. Play is a confluence of metastable forces and conditions, a network of distributed agencies (see also Taylor, Assemblage). Others like Brendan Keogh forward post-phenomenological approaches (operating under scholars like Don Ihde)—looking past the subject-centred nature of videogame research. Ultimately, these theorists situate play as an ‘exploded diagram’, challenging anthropocentric accounts.This position has proven productive in research on ‘skilled’ or ‘high-level’ play (fertile ground for considering competency-development). Emma Witkowski, T.L. Taylor (Raising), and Todd Harper have suggested that skilled play in games emerges from the management of complex embodied and technical rhythms (echoing the points raised prior by Sudnow).Placing Paratexts in PlayWhile we have these varying accounts of how skill develops within and beyond player-game relationships, these two perspectives are rarely consolidated. That said, I address some of the limited body of work that has sought to place the paratext in the complex and distributed conjunctures of play; building a vocabulary and framework via encounters with what could loosely be called post-phenomenological thinking (not dissimilar to the just surveyed accounts). The strength of this work lies in its development of a more precise view of the operational reality of playing ‘with’ paratexts. The recent work of Darshana Jayemanne, Bjorn Nansen, and Thomas Apperley theorises the outward expansion of games and play, into diverse material, social, and spatial dimensions (147), as an ‘aesthetics of recruitment’. Consideration is given to ‘paratextual’ play and skill. For instance, they provide the example of players invoking the expertise they have witnessed broadcast through Websites like Twitch.tv or YouTube—skill-building operating here across various fronts, and through various modalities (155). Players are ‘recruited’, in different capacities, through expanded interfaces, which ultimately contour phenomenological encounters with games.Ash provides a fine-grained account in research on spatiotemporal perception and videogames—one much more focused on game-skill. Ash examines how high-level communities of players cultivate ‘spatiotemporal sensitivity’ in the game Street Fighter IV through—in Stiegler’s terms—‘exteriorising’ (Fault) game information into various data sets—producing what he calls ‘technicity’. In this way, Ash suggests that these paratextual materials don’t merely ‘influence play’ (Technology 200), but rather direct how players perceive time, and habituate exteriorised temporal rhythms into their embodied facility (a translation of high-level play). By doing so, the game can be played more proficiently. Following the broadly post-phenomenological direction of these works, I develop a brief account of two paratextual practices. Like Ash, I deploy the work of Stiegler (drawing also on Ash’s usage). I utilise Stiegler’s theoretical schema of technicity to roughly sketch how some other areas of skill-building via peripheral material can be placed within the context of play—looking particularly at the conditioning of embodied faculties of player anticipation, memory and perception through play and paratext alike. A Technicity of ParatextThe general premise of Stiegler’s technicity is that the human cannot be thought of independent from their technical supplements—that is, ‘exterior’ technical objects which could include, but are not limited to, technologies (Fault). Stiegler argues that the human, and their fundamental memory structure is finite, and as such is reliant on technical prostheses, which register and transmit experience (Fault 17). This technical supplement is what Stiegler terms ‘tertiary retention’. In short, for Stiegler, technicity can be understood as the interweaving of ‘lived’ consciousness (Cinematic 21) with tertiary retentional apparatus—which is palpably felt in our orientations in and toward time (Fault) and space (including the ‘space’ of our bodies, see New Critique 11).To be more precise, tertiary retention conditions the relationship between perception, anticipation, and subjective memory (or what Stiegler—by way of phenomenologist Edmund Husserl, whose work he renovates—calls primary retention, protention, and secondary retention respectively). As Ash demonstrates (Technology), Stiegler’s framework is rich with potential in investigating the relationship between videogames and their peripheral materials. Invoking technicity, we can rethink—and expand on—commonly encountered forms of paratexts, such as game guides or walkthroughs (an example Consalvo gives in Cheating). Stiegler’s framework provides a means to assess the technical organisation (through both games and paratexts) of embodied and temporal conditions of ‘skilled play’. Following Stiegler, Consalvo’s example of a game guide is a kind of ‘exteriorisation of play’ (to the guide) that adjusts the embodied and temporal conditions of anticipation and memory (which Sudnow would tell us are key in skill-development). To work through an example, if I was playing a hard game (such as Dark Souls [From Software]), the general idea is that I would be playing from memories of the just experienced, and with expectations of what’s to come based on everything that’s happened prior (following Stiegler). There is a technicity in the game’s design here, as Ash would tell us (Technology 190-91). By way of Stiegler (and his reading of Heidegger), Ash argues a popular trend in game design is to force a technologically-mediated interplay between memory, anticipation, and perception by making videogames ‘about’ a “a future outside of present experience” (Technology 191), but hinging this on past-memory. Players then, to be ‘skilful’, and move forward through the game environment without dying, need to manage cognitive and somatic memory (which, in Dark Souls, is conventionally accrued through trial-and-error play; learning through error incentivised through punitive game mechanics, such as item-loss). So, if I was playing against one of the game’s ‘bosses’ (powerful enemies), I would generally only be familiar with the way they manoeuvre, the speed with which they do so, and where and when to attack based on prior encounter. For instance, my past-experience (of having died numerous times) would generally inform me that using a two-handed sword allows me to get in two attacks on a boss before needing to retreat to avoid fatal damage. Following Stiegler, we can understand the inscription of videogame experience in objects like game guides as giving rise to anticipation and memory—albeit based on a “past that I have not lived but rather inherited as tertiary retentions” (Cinematic 60). Tertiary retentions trigger processes of selection in our anticipations, memories, and perceptions. Where videogame technologies are traditionally the tertiary retentions in play (Ash, Technologies), the use of game-guides refracts anticipation, memory, and perception through joint systems of tertiary retention—resulting in the outcome of more efficiently beating a game.To return to my previous example of navigating Dark Souls: where I might have died otherwise, via the guide, I’d be cognisant to the timings within which I can attack the boss without sustaining damage, and when to dodge its crushing blows—allowing me to eventually defeat it and move toward the stage’s end (prompting somatic and cognitive memory shifts, which influence my anticipation in-game). Through ‘neurological’ accounts of technology—such as Stiegler’s technicity—we can think more closely about how playing with a skill-building apparatus (like a game guide) works in practice; allowing us to identify how various situations ingame can be managed via deferring functions of the player (such as memory) to exteriorised objects—shifting conditions of skill building. The prism of technicity is also useful in conceptualising some of the new ways players are building skill beyond the game. In recent years, gaming paratexts have transformed in scope and scale. Gaming has shifted into an age of quantification—with analytics platforms which harvest, aggregate, and present player data gaining significant traction, particularly in competitive and multiplayer videogames. These platforms perform numerous operations that assist players in developing skill—and are marketed as tools for players to improve by reflecting on their own practices and the practices of others (functioning similarly to the previously noted practice of TheoryCraft, but operating at a wider scale). To focus on one example, the WarCraftLogs application in WoW (Image 1) is a highly-sophisticated form of videogame analytics; the perspective of technicity providing insights into its functionality as skill-building apparatus.Image 1: WarCraftLogs. Image credit: Ben Egliston. Following Ash’s use of Stiegler (Technology), quantifying the operations that go into playing WoW can be conceptualised as what Stiegler calls a system of traces (Technology 196). Because of his central thesis of ‘technical existence’, Stiegler maintains that ‘interiority’ is coincident with technical support. As such, there is no calculation, no mental phenomena, that does not arise from internal manipulation of exteriorised symbols (Cinematic 52-54). Following on with his discussion of videogames, Ash suggests that in the exteriorisation of gameplay there is “no opposition between gesture, calculation and the representation of symbols” (Technology 196); the symbols working as an ‘abbreviation’ of gameplay that can be read as such. Drawing influence from this view, I show that ‘Big Data’ analytics platforms like WarCraftLogs similarly allow users to ‘read’ play as a set of exteriorised symbols—with significant outcomes for skill-building; allowing users to exteriorise their own play, examine the exteriorised play of others, and compare exteriorisations of their own play with those of others. Image 2: WarCraftLogs Gameplay Breakdown. Image credit: Ben Egliston.Image 2 shows a screenshot of the WarCraftLogs interface. Here we can see the exteriorisation of gameplay, and how the platform breaks down player inputs and in-game occurrences (written and numeric, like Ash’s game data). The screenshot shows a ‘raid boss’ (where players team up to defeat powerful computer-controlled enemies)—atomising the sequence of inputs a player has made over the course of the encounter. This is an accurate ledger of play—a readout that can speak to mechanical performance (specific ingame events occurred at a specific time), as well as caching and providing parses of somatic inputs and execution (e.g. ability to trace the rates at which players expend in-game resources can provide insights into rapidity of button presses). If information falls outside what is presented, players can work with an Application Programming Interface to develop customised readouts (this is encouraged through other game-data platforms, like OpenDota in Dota 2). Through this system, players can exteriorise their own input and output or view the play of others—both useful in building skill. The first point here—of exteriorising one’s own experience—resonates with Stiegler’s renovation of Husserl's ‘temporal object’—that is, an object that exists in and is formed through time—through temporal fluxes of what appears, what happens and what manifests itself in disappearing (Cinematic 14). Stiegler suggests that tertiary retentional apparatus (e.g. a gramophone) allow us to re-experience a temporal object (e.g. a melody) which would otherwise not be possible due to the finitude of human memory.To elaborate, Stiegler argues that primary memories recede into secondary memory (which is selective reactivation of perception), but through technologies of recording, (such as game-data) we can re-experience these things verbatim. So ultimately, games analytics platforms—as exteriorised technologies of recording—facilitate this after-the-fact interplay between primary and secondary memory where players can ‘audit’ their past performance, reflecting on well-played encounters or revising error. These platforms allow the detailed examination of responses to game mechanics, and provide readouts of the technical and embodied rhythms of play (which can be incorporated into future play via reading the data). Beyond self-reflection, these platforms allow the examination of other’s play. The aggregation and sorting of game-data makes expertise both visible and legible. To elaborate, players are ranked on their performance based on all submitted log-data, offering a view of how expertise ‘works’.Image 3: Top-Ranking Players in WarCraftLogs. Image credit: Ben Egliston.Image 3 shows the top-ranked players on an encounter (the top 10 of over 100,000 logs), which means that these players have performed most competently out of all gameplay parses (the metric being most damage dealt per-second in defeating a boss). Users of the platform can look in detail at the actions performed by top players in that encounter—reading and mobilising data in a similar manner to game-guides; markedly different, however, in terms of the scope (i.e. there are many available logs to draw from) and richness of the data (more detailed and current—with log rankings recalibrated regularly). Conceptually, we can also draw parallels with previous work (see: Ash, Technology)—where the habituation of expert game data can produce new videogame technicities; ways of ‘experiencing’ play as ‘higher-level’ organisation of space and time (Ash, Technology). So, if a player wanted to ‘learn from the experts’ they would restructure their own rhythms of play around high-level logs which provide an ordered readout of various sequences of inputs involved in playing well. Moreover, the platform allows players to compare their logs to those of others—so these various introspective and outward-facing uses can work together, conditioning anticipations with inscriptions of past-play and ‘prosthetic’ memories through other’s log-data. In my experience as a WoW player, I often performed better (or built skill) by comparing and contrasting my own detailed readouts of play to the inputs and outputs of the best players in the world.To summarise, through technicity, I have briefly shown how exteriorising play shifts the conditions of skill-building from recalibrating msnesic and anticipatory processes through ‘firsthand’ play, to reworking these functions through engaging both games and extrinsic objects, like game guides and analytics platforms. Additionally, by reviewing and adopting various usages of technicity, I have pointed out how we might more holistically situate the gaming paratext in skill building. Conclusion There is little doubt—as exemplified through both scholarly and popular interest—that paratextual videogame material reframes modes of building game skill. Following recent work, and by providing a brief account of two paratextual practices (venturing the framework of technicity, via Stiegler and Ash—showing the complication of memory, perception, and anticipation in skill-building), I have contended that videogame-skill building—via paratextual material—can be rendered a process of operating outside of, but still caught up in, the complex assemblages of time, bodies, and technical architectures described by Sudnow at this article’s outset. Additionally, by reviewing and adopting ideas associated with technics and post-phenomenology, this article has aimed to contribute to the development of more ‘complete’ accounts of the processes and practices comprising skill building regimens of contemporary videogame players.References Ash, James. “Technology, Technicity and Emerging Practices of Temporal Sensitivity in Videogames.” Environment and Planning A 44.1 (2012): 187-201.———. “Technologies of Captivation: Videogames and the Attunement of Affect.” Body and Society 19.1 (2013): 27-51.Consalvo, Mia. Cheating: Gaining Advantage in Videogames. Cambridge: Massachusetts Institute of Technology P, 2007. Crogan, Patrick, and Helen Kennedy. “Technologies between Games and Culture.” Games and Culture 4.2 (2009): 107-14.Donaldson, Scott. “Mechanics and Metagame: Exploring Binary Expertise in League of Legends.” Games and Culture (2015). 4 Jun. 2015 <http://journals.sagepub.com/doi/abs/10.1177/1555412015590063>.From Software. 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Web browser application. 2017.Paul, Christopher A. “Optimizing Play: How Theory Craft Changes Gameplay and Design.” Game Studies: The International Journal of Computer Game Research 11.2 (2011). May 2011 <http://gamestudies.org/1102/articles/paul>.Salen, Katie, and Eric Zimmerman. Rules of Play: Game Design Fundamentals. Cambridge: Massachusetts Institute of Technology P, 2004.Stiegler, Bernard. Technics and Time, 1: The Fault of Epimetheus. Stanford: Stanford UP, 1998.———. For a New Critique of Political Economy. Cambridge: Polity, 2010.———. Technics and Time, 3: Cinematic Time and the Question of Malaise. Stanford: Stanford UP, 2011.Sudnow, David. Pilgrim in the Microworld. New York: Warner Books, 1983.Taylor, T.L. “The Assemblage of Play.” Games and Culture 4.4 (2009): 331-39.———. Raising the Stakes: E-Sports and the Professionalization of Computer Gaming. Cambridge: Massachusetts Institute of Technology P, 2012.WarCraftLogs. WarCraftLogs. 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ABSTRACTThe most relevant phenomenon of this last decade in the field of semiconductor memories has been the explosive growth of the Flash memory market, driven by cellular phones and other types of electronic portable equipments (palm top, mobile PC, mp3 audio player, digital camera and so on). Moreover, in the coming years portable systems will ask even more non volatile memories either with high density and very high writing throughput for data storage application, or with fast random access for code execution in place. The strong consolidated know-how (more than ten years of experience), the flexibility and the cost make the floating gate Flash Memory a largely utilized, well-consolidated and mature technology for most of the non-volatile memory application. Today Flash sales represent a considerable amount of the overall semiconductor market.Nowadays two of the several cell architecture proposed up to now can be considered as industry standard: the common ground NOR Flash that due to its versatility is addressing both the code and data storage segments and the NAND Flash, optimized for the data storage market.The exploitation of the multilevel approach at each technology node allows the increase of the memory efficiency, about doubling the density at the same chip size, widening the application range and reducing the cost per bit.In this paper the main issues related to both NOR and NAND Flash memory technology will be summarized, with the aim of describing both the basic functionality of the memory cell and the main cell architecture today consolidated. Both cells are basically a floating-gate MOS transistor, programmed by channel hot electron (NOR) or by Fowler-Nordheim tunneling (NAND) and erased by Fowler-Nordheim tunnel. The main reliability properties, charge retention and endurance, are presented, together with some comments on the basic physical mechanisms responsible for.A couple of innovative approaches to floating gate cell evolution, namely nanocrystal memory and 3-D cell will be described.Finally the Flash cell scaling issues will be covered, pointing out the main challenges. The Flash cell scaling has been demonstrated to be really possible and to be able to follow the Moore's law down to the 90 nm technology generations. The technology development and the consolidated know-how are expected to sustain the scaling trend down to the 50 nm technology node and below as forecasted by the ITRS roadmap.

Acute urinary retention is a urological emergency presenting with a sudden inability to pass urine due to mechanical or functional reason characterized by suprapubic pain and distension requiring urgent bladder drainage. Acute urinary retention is ten times more common in males than females. Female genital mutilation comprises all surgical procedures involving partial or total removal of the female external genitalia or other injuries to the female genital organ for cultural and other non-therapeutic reasons. We present an 11 year old girl who was referred from a primary health centre with recurrent history of acute urinary retention following a female genital mutilation done 5 days prior to presentation, she was said to have been having suprapubic tapping of the urine to relive her of the retention as the health providers were unable to identify the urethral orifice for catheterization. On examination; she was in painful distress with complain of suprapubic pain and urge to pass urine, there is tender suprapubic distention, the left upper labia majora, minora and clitoris were severed, the urethral meatus distorted. Examination under anaesthesia with suprapubic cystostomy and urethral catheterisation was done and the patient was placed on sitz bath and genital toileting. We report a case of acute urinary retention in an 11 year old girl following a female genital mutilation five days earlier.

Abstract The objectives of this study were to evaluate the current status of exposure to bio-engineering research in community college (CC) students and University of Maryland Baltimore County (UMBC) students, and to estimate relationships between research activities sponsored by the Mechanical Engineering (ME) S-STEM Scholarship Program and improvement in student enrollment/diversification, retention rates, and graduation rates. The analysis drew on data from ME undergraduate academic records at UMBC from 2008 to 2019. A survey was designed to assess the research exposure of CC and UMBC students and their evaluation of the research components included in recruitment and curriculum activities. Results show that exposure to research measured by attending a research seminar was low for the participants, around 37% for CC students and 21% for ME students at UMBC. The survey results indicate the positive impact of the scholarship programs at UMBC on the research exposure and research experience. The impact is more evident in students who originally transferred from a CC. The large increase in recruited female and CC students over the past 10 years indicated that the research-related activities of the ME S-STEM program played an instrumental role in those increases. Because of the research-related activities, the ME S-STEM program achieved retention and graduation rates higher than those in the ME undergraduate program (89% versus 60% for the 6 year graduation rate), as well a higher percentage of students enrolled in graduate school (30% versus 10%). We conclude that there is still a need to implement research-related activities in the ME undergraduate program, starting with student recruitment and continuing through the academic program. Results suggest that there is a positive impact of ME S-STEM research activities on student diversification, retention rates, and percentage of our graduates who are pursuing graduate degree.

AbstractImplantation of a malleable composite hydroxylapatite/plaster of Paris mixture moistened with calcium hydroxide solution was performed in periapical defects which could not be treated successfully by nonsurgical procedures. A 1.5:1 mixture of sintered hydroxylapatite particles (OrthoMatrix HA-500) and plaster of Paris (USC Medical Grade Calcium Sulfate Hemihydrate B) containing 0.85% K2 SO4 is moistened with Calcium Hydroxide Topical Solution, USP and formed into a malleable mass. This is placed into the surgical defect, shaped and covered with resorbable polyester mesh. The flap is replaced and pressure applied for 5 minutes before suturing. Sutures are removed in I week and x-rays are taken immediately after surgery and at six month intervals. In all types of defects in which the material was employed, the prognosis for postsurgical tooth retention was improved and short term success was 91%. The success achieved suggests that this implantation procedure should receive wider application for complex endodontic periapical osseous defects.

We report a case of complete esophageal obstruction caused by continuous enteral nutrition infusion via nasogastric tube. A 77 year old man received mechanical ventilation due to severe pneumonia and severe respiratory distress. He began using enteral nutrition emulsion (TPF) through a nasogastric tube on admission. 15 days later, due to the difficulty of re-inserting the nasogastric tube, endoscopy found a large number of coagulations in the esophagus, resulting in complete esophageal obstruction. We remove a small part of the foreign body with a net basket under gastroscope. After the operation, the nasogastric tube was placed in the middle of the esophagus again, which was perfused with 5% sodium bicarbonate and vinegar through the gastric tube. One week later, the esophagus was completely unobstructed by gastroscopy. A conclusion can be drawn that the precipitation and coagulation of TPF can lead to the whole esophageal obstruction. Endoscopic removal of foreign bodies, sodium bicarbonate and vinegar retention in the esophagus can treat the food obstruction caused by TPF.

AbstractA laboratory leaching test has been performed as part of a project to evaluate the suitability of tuff rocks at Yucca Mountain, Nevada, as a site for a high-level nuclear waste repository. Glass samples were placed in water inside tuff vessels, and then the tuff vessels were placed in water inside Teflon containers. Glass-component leach rates and migration through the tuff were measured for samples of the ATM- 9actinide glass, which is a PNL 76-68 based glass doped with low levels of 99Tc, 237Np, 238U and 239Pu to simulate wastes. Disc samples of this glass were leached at 90°C for 30, 90, and 183 days inside tuff vessels using a natural groundwater (J-13 well-water) as the leachant. Some samples were held by 304L stainless steel supports to evaluate the effect of this metal on the release rate of glass constituents. At the end of each leaching interval, the J-13 water present inside and outside the rock vessel was analyzed for glass components in solution.On the basis of these analyses, boron, molybdenum, and technetium appear to migrate through the rock at rates that depend on the porosity of each vessel and the time of reaction. The actinide elements (uranium, neptunium, and plutonium) were found only in the inner leachate. Sodium, silicon, and strontium are present in the rock as well as in the J-13 water, and the addition of these elements from the glass could not be determined. Normalized elemental mass loss values for boron, molybdenum, and technetium were calculated using the combined concentrations of the inner and outer leachates and assuming a negligible retention on the rock. The maximum normalized release was 2.3 g/m for technetium. Boron, molybdenum, technetium, and neptunium were released linearly with respect to each other, with boron and molybdenum released at about 85% of the technetium rate, and neptunium at 5-10% of the technetium rate. Plutonium was found at low levels in the inner leachate but was strongly sorbed on the steel and Teflon supports. Neptunium was sorbed to a lesser extent. Future analysis of the tuff vessels will determine whether the actinides were strongly sorbed on the surface of the tuff rock.

Compare with the torque value recommended by the manufacturer, the values of maximum closing torques generated by volunteers of the male and female gender, with and without experience in implant-prosthesis, for tightening the screw UCLA abutment retention. The hypotheses tested were that the greatest experience in the field would not influence the value of the applied torque, as there would be no difference between volunteers from different genders. In this way, 266 volunteers were classified according to their expertise in pre-clinical (PC), clinical (C) and professional (P). Were placed seated, simulating normal forward work position in front a digital torque meter. A specimen composed of an external hex implant embedded in modified polyester resin, a metal crown and its retaining screw was attached on torque meter. The participants were provided with directions to tighten the abutment retaining screw by using a manual torque driver and apply full force in one movement of rotation. The professional group achieved the highest mean manual torque (15.80 N / cm); males (14.96 N/cm) scores a higher than females (02.11 N/cm). They could not reach the torque value recommended by the manufacturer. Thus, the factors that influence the manual application of torque include the level of clinical experience and the physical strength of the operator. The conclusion is that the use of a calibrated mechanical driver torque is essential to apply a suitable and controlled torque value and capable of promoting a proper preload and maintaining the screwed joint for long periods.Descriptors: Dental Implants; Dental Prosthesis, Implant-Supported; Stress, Mechanical.

Abstract The goal of the study is to identify optimal breakwater designs to be placed on the banks of various water bodies in coastal Louisiana, to prevent the coastal erosion. Coastal erosion is a significant concern for Louisiana's wavy coastline. The loss of coastal wetlands is threatening the environment and the economic development. One of the ways to prevent coastal erosion and wetland losses is by using breakwaters designed to reduce the wave energy and change the transport of sediments brought by the waves. The objective of this research is to analyze the turbulent characteristics around specially designed three-dimensional (3D) breakwaters, and its impact on sediment deposition under coastal wave actions. Both computational fluid dynamics (CFD) simulations and experimental measurements were conducted. In order to validate the CFD models used for this study, the simulation results were compared to data measured from a scale-down experiment. Once the validity of the CFD models has been confirmed on three miniature panels, namely, a solid panel, a panel with three holes, and a panel with eight holes, the simulations were scaled up to the actual size of the designed breakwater panels for tests. The breakwater designs aim to allow sediment pass through the holes, to deposit sediment at target areas, and to reduce wave actions. There were three different panel-design cases simulated in this study. The results of 3D CFD simulations of these panels were compared and analyzed to determine the performance of each design in terms of wave reduction and sediment retention.