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Статті в журналах з теми "Early injection"
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Li, Y., H. Zhao, N. Brouzos, and B. Leach. "Managing controlled auto-ignition combustion by injection on a direct-injection gasoline engine." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 221, no. 9 (September 1, 2007): 1125–37. http://dx.doi.org/10.1243/09544070jauto372.
Повний текст джерелаАнотація:
Controlled auto-ignition (CAI) combustion in gasoline engines has great potential for reducing both NO x emissions and fuel consumption, but its application is still hindered by the lack of direct control of combustion phasing and by the limited CAI operation range. In this paper, the effect of injection timing and split injection on CAI combustion is presented in a single-cylinder direct-injection gasoline engine with an air-assisted injector. The CAI combustion was achieved by trapping some of the burned gases within the cylinder by using low-lift short-duration camshafts and early closure of the exhaust valves. During the experiments, the engine speed was varied from 1200 to 2400 r/min and the air-fuel ratio was altered from stoichiometric to the misfire limit. Both single and split injections were investigated at different injection timings and fuel quantities. The experimental results show that injection timing has an important effect on CAI combustion for single and split injections. Early injection produces faster and more stable combustion, less hydrocarbon and CO emissions, but very rapid heat release rates and higher NO x emissions. The CAI operation range could be extended significantly by early injection. Split injection gives even further extension of the CAI range in both stoichiometric and lean mixture operations. These results indicate that optimizing the injection timing and using split injection is an effective way to control and extend CAI operation in a direct-injection gasoline engine.
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Carlucci, P., A. Ficarella, and D. Laforgia. "Effects on combustion and emissions of early and pilot fuel injections in diesel engines." International Journal of Engine Research 6, no. 1 (February 1, 2005): 43–60. http://dx.doi.org/10.1243/146808705x7301.
Повний текст джерелаАнотація:
Different injection strategies applied to a common rail direct injection diesel engine were tested for different engine torque and speed conditions. The injection strategies differ for the use of early and pilot injections; during the tests the injection parameters were varied, in terms of duration and timing of early, pilot, and main injections. The combustion behaviour and the engine performances, in terms of brake specific fuel consumption, were analysed. In addition, data on nitrogen oxides (NOx), total unburned hydrocarbons, and particulate emissions were collected. The injection strategy based on both early and pilot injections has been compared with the techniques using either pilot or early injections. Results show that, particularly at lower values of engine torque and speed, the small fuel quantity injected during early injection, coupled with the pilot injection, leads to comparable levels or even to a sensible reduction in fuel consumption compared with the only-pilot or only-early injection cases. Furthermore, a reduction in NOx and particulate is generally observed, while the level of unburned hydrocarbons usually increases. Experimental tests have shown that, using the early injection, a very lean premixed charge is obtained, both globally and locally, inside the combustion chamber, thus avoiding diesel problems (in particular, high NOx and soot production), mainly caused by the locally rich mixture. On the other hand, by using the pilot injection the ignition delay of the main injection is reduced, contributing to the NOx reduction.
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Lu, Xiang’an, Hanqiao Jiang, and Yanli Pei. "A New Injectivity Prediction Model for Early Polymer Injection." International Journal of Materials, Mechanics and Manufacturing 3, no. 4 (2015): 243–48. http://dx.doi.org/10.7763/ijmmm.2015.v3.204.
Повний текст джерела
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Jeftić, Marko, Zhenyi Yang, Graham T. Reader, and Ming Zheng. "Fuel efficiency analysis and peak pressure rise rate improvement for neat n-butanol injection strategies." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 231, no. 1 (August 5, 2016): 50–65. http://dx.doi.org/10.1177/0954407016632141.
Повний текст джерелаАнотація:
Engine tests were conducted to investigate the efficiency and the peak pressure rise rate performance of different fuel injection strategies for the direct injection of neat n-butanol in a compression ignition engine. Three different strategies were tested: a single-shot injection; a pilot injection; a post-injection. A single-shot injection timing sweep revealed that early injections had the highest indicated efficiency while late injections reduced the peak pressure rise rate at the cost of a slightly reduced thermal efficiency. Delayed single-shot injections also had increased emissions of nitrogen oxides, total hydrocarbon and carbon monoxide. Addition of a pilot injection had a negative effect on the peak pressure rise rate. Because of the low cetane number of butanol and the relatively lean and well-premixed air–fuel mixture, the pilot injection failed to autoignite and instead ignited simultaneously with the main injection. This resulted in slightly increased peak pressure rise rates and significantly increased unburned butanol hydrocarbon emissions. Conversely, the use of an early post-injection produced a noticeable engine power output and allowed the main injection to be shortened and the peak pressure rise rate to be substantially reduced. However, relatively early post-injections slightly reduced the indicated efficiency and increased the nitrogen oxide emissions and the carbon monoxide emissions compared with the single-shot injection strategy. These results recommended the use of a single-shot injection for low loads and medium loads owing to a superior thermal efficiency and suggested that the application of a post-injection may be more suited to high-load conditions because of the substantially reduced peak pressure rise rates.
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Lewis, Emma, Khalid Merghani, Iain Robertson, Jonathon Mulford, Ben Prentice, Ronnie Mathew, Peter Van Winden, and Kathryn Ogden. "The effectiveness of leucocyte-poor platelet-rich plasma injections on symptomatic early osteoarthritis of the knee: the PEAK randomized controlled trial." Bone & Joint Journal 104-B, no. 6 (June 1, 2022): 663–71. http://dx.doi.org/10.1302/0301-620x.104b6.bjj-2021-1109.r2.
Повний текст джерелаАнотація:
Aims Platelet-rich plasma (PRP) intra-articular injections may provide a simple and minimally invasive treatment for early-stage knee osteoarthritis (OA). This has led to an increase in its adoption as a treatment for knee OA, although there is uncertainty about its efficacy and benefit. We hypothesized that patients with early-stage symptomatic knee OA who receive multiple PRP injections will have better clinical outcomes than those receiving single PRP or placebo injections. Methods A double-blinded, randomized placebo-controlled trial was performed with three groups receiving either placebo injections (Normal Saline), one PRP injection followed by two placebo injections, or three PRP injections. Each injection was given one week apart. Outcomes were prospectively collected prior to intervention and then at six weeks, three months, six months, and 12 months post-intervention. Primary outcome measures were Knee Injury and Osteoarthritis Outcome Score (KOOS) and EuroQol five-dimension five-level index (EQ-5D-5L). Secondary outcomes included visual analogue scale for pain and patient subjective assessment of the injections. Results A total of 102 patients were recruited. The follow-up period was 12 months, at intervals of six weeks, 12 weeks, six months, and 12 months. KOOS-Total significantly improved in all groups at these time intervals compared to pre-injection. There was an improvement in EQ-5D-5L index scores in saline and single injection groups, but not in the multiple injection group. Comparison of treatment groups showed no additional beneficial effect of single or multiple PRP injections above that displayed in the saline injection group. Subjective patient satisfaction and recommendation of treatment received demonstrated a similar pattern in all the groups. There was no indication of superiority of either single or multiple PRP injections compared to saline injections. Conclusion There is no evidence that single or multiple PRP had any additional beneficial effect compared to saline injection up to 12 months, follow-up after treatment of early stage symptomatic OA of the knee. Cite this article: Bone Joint J 2022;104-B(6):663–671.
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Finsen, Vilhjalmur, Ante M. Kalstad, and Rainer G. Knobloch. "Corticosteroid injection for coccydynia." Bone & Joint Open 1, no. 11 (November 1, 2020): 709–14. http://dx.doi.org/10.1302/2633-1462.111.bjo-2020-0146.
Повний текст джерелаАнотація:
Aims We aimed to establish the short- and long-term efficacy of corticosteroid injection for coccydynia, and to determine if betamethasone or triamcinolone has the best effect. Methods During 2009 to 2016, we treated 277 patients with chronic coccydynia with either one 6 mg betamethasone or one 20 mg triamcinolone cortisone injection. A susequent injection was given to 62 (26%) of the patients. All were reviewed three to four months after injection, and 241 replied to a questionnaire a mean of 36 months (12 to 88) after the last injection. No pain at the early review was considered early success. When the patient had not been subsequently operated on, and indicated on the questionnaire that they were either well or much better, it was considered a long-term success. Results At the three- to four-month review, 22 (9%) reported that they had no pain. The long-term success of one injection was 15% and rose to 29% after a second injection. Logistic regression tests showed that both early success (odds ratio (OR) 5.5, 95% confidence interval (CI) 2.1 to 14.4; p = 0.001) and late success (OR 3.7, 95% CI 1.7 to 8.3; p = 0.001) was greater with triamcinolone than with betamethasone. Late success was greater for patients with symptoms for less than 12 months (OR 3.0, 95% CI 1.4 to 6.7; p = 0.006). We saw no complications of the injections. Conclusion We conclude that the effect of corticosteroid injection for coccygodynia is moderate, possibly because we used modest doses of the drugs. Even so, they seem worthwhile as they are easily and quickly performed, and complications are rare. If the choice is between injections of betamethasone or triamcinolone, the latter should be selected. Cite this article: Bone Joint Open 2020;1-11:709–714.
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An, Seoung Hyun, and Woo Jin Jeong. "Early-scatter laser photocoagulation promotes the formation of collateral vessels in branch retinal vein occlusion." European Journal of Ophthalmology 30, no. 2 (February 5, 2019): 370–75. http://dx.doi.org/10.1177/1120672119827857.
Повний текст джерелаАнотація:
Purpose: To investigate the effect of early-scatter laser photocoagulation on the formation of collateral vessels in branch retinal vein occlusion. Methods: The medical records of 40 cases (40 patients) of branch retinal vein occlusion with macular edema were retrospectively reviewed. Of them, 23 patients were treated with intravitreal bevacizumab injection and 17 patients underwent intravitreal bevacizumab injection with additional laser treatment. Early-scatter laser photocoagulation was applied for capillary non-perfusion areas, regardless of retinal neovascularization. Collateral vessel presence, recurrence rate of macular edema, and number of intravitreal bevacizumab injections were compared between the groups. Results: During the follow-up period, collateral vessel formation was noted in 10/23 eyes (43.5%) in the intravitreal bevacizumab injection group and 15/17 eyes (88.2%) in the laser combined treatment group ( p = 0.004). The recurrence rate of macular edema was lower in the laser combined treatment group (29.4%) than in the intravitreal bevacizumab injection group (65.2%); this difference was statistically significant ( p = 0.025). The average numbers of intravitreal bevacizumab injections were 3.57 ± 3.23 in the intravitreal bevacizumab group and 2.14 ± 2.26 in the laser combined treatment group ( p = 0.044). Conclusion: Early-scatter laser photocoagulation promotes collateral vessel formation; the presence of collateral vessels seemed to affect the course of macular edema in branch retinal vein occlusion. Combined early-scatter laser photocoagulation treatment after intravitreal bevacizumab injection lowered the recurrence rate of macular edema and number of intravitreal bevacizumab injections in the cases of branch retinal vein occlusion.
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Standl, Thomas G., Ernst-Peter Horn, Michael Luckmann, Marc-Alexander Burmeister, Stefan Wilhelm, and Jochen Schulte am Esch. "Subarachnoid Sufentanil for Early Postoperative Pain Management in Orthopedic Patients." Anesthesiology 94, no. 2 (February 1, 2001): 230–38. http://dx.doi.org/10.1097/00000542-200102000-00011.
Повний текст джерелаАнотація:
Background Continuous spinal anesthesia is frequently used for intraoperative anesthesia but rarely for postoperative pain management. Because even small doses of local anesthetics can be associated with motor deficits, subarachnoid opioid injection may be an alternative. Methods Eighty patients randomly received a subarachnoid injection of 10 microg sufentanil, 5 mg bupivacaine, 2.5 microg sufentanil plus 2.5 mg bupivacaine, or saline through 28-gauge spinal microcatheters for early postoperative pain relief after major lower-limb surgery (n = 20 in each group). Hemodynamic and respiratory parameters, pain scores, and motor function were monitored, and sufentanil concentrations in plasma and cerebrospinal fluid were measured. Ten additional patients received up to three repetitive injections of 10 microg sufentanil over 24 h. Results All drugs provided excellent pain relief within 15 min after injection, lasting 128 +/- 61 min with sufentanil, 146 +/- 74 min with bupivacaine, and 167 +/- 78 min with the mixture. Patients receiving bupivacaine showed the highest cephalad extension of sensory block (median, T6) and the most intense motor block, whereas patients given only sufentanil had no motor deficit. The duration of analgesia was shorter after subsequent sufentanil injection (100-115 min) than after the first injection (198 +/- 70 min). Six of 50 patients with sufentanil experienced a short episode of respiratory depression within 30 min after the first injection. Cerebrospinal fluid concentrations of sufentanil peaked at 5 min after injection (183 +/- 167 ng/ml) but were at the level of detection in the plasma. Conclusions Sufentanil injected through microspinal catheters provided profound pain relief without impairing motor function when compared with bupivacaine. However, close monitoring remains mandatory in this setting.
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Jenkins, A. K. L., P. M. Forster, and L. S. Jackson. "The effects of timing and rate of marine cloud brightening aerosol injection on albedo changes during the diurnal cycle of marine stratocumulus clouds." Atmospheric Chemistry and Physics 13, no. 3 (February 8, 2013): 1659–73. http://dx.doi.org/10.5194/acp-13-1659-2013.
Повний текст джерелаАнотація:
Abstract. The marine-cloud brightening geoengineering technique has been suggested as a possible means of counteracting the positive radiative forcing associated with anthropogenic atmospheric CO2 increases. The focus of this study is to quantify the albedo response to aerosols injected into marine stratocumulus cloud from a point source at different times of day. We use a cloud-resolving model to investigate both weakly precipitating and non-precipitating regimes. Injection into both regimes induces a first indirect aerosol effect. Additionally, the weakly precipitating regime shows evidence of liquid water path gain associated with a second indirect aerosol effect that contributes to a more negative radiative forcing, and cloud changes indicative of a regime change to more persistent cloud. This results in a cloud albedo increase up to six times larger than in the non-precipitating case. These indirect effects show considerable variation with injection at different times in the diurnal cycle. For the weakly precipitating case, aerosol injection results in domain average increases in cloud albedo of 0.28 and 0.17 in the early and mid morning (03:00:00 local time (LT) and 08:00:00 LT respectively) and 0.01 in the evening (18:00:00 LT). No cloud develops when injecting into the cloud-free early afternoon (13:00:00 LT). However, the all-sky albedo increases (which include both the indirect and direct aerosol effects) are highest for early morning injection (0.11). Mid-morning and daytime injections produce increases of 0.06, with the direct aerosol effect compensating for the lack of cloud albedo perturbation during the cloud-free early afternoon. Evening injection results in an increase of 0.04. For the weakly precipitating case considered, the optimal injection time for planetary albedo response is the early morning. Here, the cloud has more opportunity develop into a more persistent non-precipitating regime prior to the dissipative effects of solar heating. The effectiveness of the sea-spray injection method is highly sensitive to diurnal injection time and the direct aerosol effect of an intense aerosol point source. Studies which ignore these factors could overstate the effectiveness of the marine cloud brightening technique.
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Shahriar, Hossain, Sarah North, and Wei-Chuen Chen. "Early Detection of SQL Injection Attacks." International Journal of Network Security & Its Applications 5, no. 4 (July 31, 2013): 53–65. http://dx.doi.org/10.5121/ijnsa.2013.5404.
Повний текст джерелаДисертації з теми "Early injection"
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Hosseini-Nasab, Hasan. "The early cost estimation of injection moulded components." Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250821.
Повний текст джерела
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André, Mathieu. "Potentiel de la combustion HCCI et injection précoce." Phd thesis, Université d'Orléans, 2010. http://tel.archives-ouvertes.fr/tel-00597281.
Повний текст джерелаАнотація:
Depuis plusieurs années, l'une des problématiques sociétales est de diminuer les émissions de polluants et de gaz à effet de serre dans l'atmosphère. Le secteur du transport terrestre est directement concerné par ces considérations. Le moteur Diesel semble promis à un bel avenir grâce à son rendement supérieur à celui du moteur à allumage commandé, conduisant à de plus faibles rejets de CO2. Cependant, sa combustion génère des émissions d'oxyde d'azote (NOx) et de particules dans l'atmosphère. Les normes anti-pollution étant de plus en plus sévères et les incitations à diminuer les consommations de carburant de plus en plus fortes, le moteur Diesel est confronté à une problématique NOx/particules/consommation toujours plus difficile à résoudre. Une des voies envisagées consiste à modifier le mode de combustion afin de limiter les émissions polluantes à la source tout en conservant de faibles consommations. La voie la plus prometteuse est la combustion HCCI (Homogeneous Charge Compression Ignition) obtenue par injections directes précoces. Plusieurs limitations critiques doivent cependant être revues et améliorées : le mouillage des parois par le carburant liquide et le contrôle de la combustion à forte charge. Le but de cette thèse est ainsi de mieux comprendre les phénomènes mis en jeu lors de la combustion HCCI à forte charge obtenue par des multi-injections directes précoces. Une méthodologie a été mise au point afin de détecter le mouillage des parois du cylindre, ce qui a permis de comprendre l'effet du phasage et de la pression d'injection sur cette problématique. Une stratégie optimale de multi-injections permettant d'atteindre une charge élevée sans mouiller les parois a ainsi été développée et choisie. Nous avons ensuite pu mettre en évidence le potentiel de la stratification par la dilution en tant que moyen de contrôle de la combustion en admettant le diluant dans un seul des 2 conduits d'admission. Des mesures réalisées en complémentarité sur le même moteur mais en version 'optique', ont permis, à partir de la technique de Fluorescence Induite par Laser, de montrer que concentrer le diluant dans les zones réactives où se situe le carburant permet un meilleur contrôle de la combustion, ce qui permet d'amener le taux de dilution a des niveaux faisables technologiquement.
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Arthozoul, Simon Jean Louis. "Study of the association of premixed and diffusive combustion processes on the combustion and pollutant emissions in a mid-size Diesel engine." Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/63262.
Повний текст джерелаАнотація:
[EN] The main objective of this thesis is the analysis and comprehension of the association of two different combustion concepts (premixed and diffusive combustion) on the pollutant emissions and engine performance in a mid-size Diesel engine. The evaluation is performed at mid and high load conditions, where the implementation of premixed combustion is generally challenging.
The association of the two combustion modes is hard to attain in a conventional Diesel engine, especially the preparation of the premixed charge with early pilot injection. Therefore, the approach followed during the study has been divided in two main steps: first, the bibliography on the subject is reviewed and two strategies avoiding the main issues mentioned in the literature are grossly evaluated in order to estimate their potential for emission reduction. Second, a deeper study of the combustion processes and emissions formation is performed, focusing only on the partially premixed combustion strategies that actually have the potential for emissions reduction.
Along the second part of the study, the association of premixed and diffusive combustion is evaluated together with variation of conventional calibration parameters such as the intake oxygen concentration (via exhaust gas recirculation), the boost pressure and the start of the main injection timing, at different engine speed and load conditions. A cross analysis of the results obtained is performed in order to understand the key reasons that permit the reduction of the pollutant emissions with this strategy.
In a final part of the thesis, the partially premixed combustion strategies studied are confronted with the challenges they might face when really considered for their introduction in a production engine (oil-dilution, noise...) to finally conclude on their technological potential.[ES] El objetivo principal de la Tesis es el an álisis y la comprensi ón de la asociaci ón de dos conceptos de combusti ón diferentes (combusti ón en premezcla y por difusi ón) en las emisiones contaminantes y las prestaciones en un motor Diesel de cilindrada media. La evaluaci ón se realiza en condiciones de media y alta carga, en la cuales la implementaci ón de una combusti ón premezclada es generalmente complicada. La asociaci ón de los dos modos de combusti ón es dif cil de conseguir en un motor Diesel convencional, especialmente la preparaci ón de la carga premezclada con inyecci ón piloto adelantada. Por esa raz ón, el estudio se divide en dos partes principales: primero se revisa la bibliograf ía acerca del tema, centrando la atenci ón en dos estrategias que permiten evitar los principales problemas evocados en la literatura, determinando su potencial para la reducci ón de las emisiones contaminantes. En un segundo lugar, se realiza un estudio m as profundo de los procesos de combusti ón y de formaci ón de contaminantes, centr ándose únicamente en las estrategias de combusti ón parcialmente premezclada que sí tienen el potencial para reducir las emisiones contaminantes. En la segunda parte del estudio, se aborda la asociaci ón de combustiones premezclada y por difusi ón junto con la variaci ón de par ametros de calibraci on convencionales como la concentraci ón de ox ígeno en la admisi ón (por medio de recirculaci ón de los gases de escape), la presi ón de sobrealimentaci ón y el inicio de la inyecci ón principal, en diferentes condiciones de r egimen y de carga del motor. El an álisis cruzado de los resultados se realiza con el af án de entender las razones claves de los procesos que permiten la reducci ón de las emisiones contaminantes con esta estrategia. Como etapa final de esta tesis, se confrontan las estrategias de combusti ón parcialmente premezclada estudiadas con los problemas a los cuales podr ían llevar si realmente se considerar a su implementaci ón y un motor de serie (diluci ón de aceite, ruido...) para finalmente concluir sobre su potencial tecnol ógico.
[CAT] L'objectiu principal de la tesi es l'an alisi i la comprensi o de l'associaci o de dos conceptes de combusti o diferents (combusti o en premescla i per difusi o) en les emissions contaminants i les prestacions en un motor Di esel de cilindrada mitjana. L'avaluaci o es realitza en condicions de mitja i alta c arrega, en las quals la implementaci o d'una combusti o premesclada es generalment complicada. L'associaci o dels dos modes de combusti o es dif cil d'aconseguir en un motor Di esel convencional, especialment la preparaci o de la c arrega premesclada amb injecci o pilot avan cada. Per eixa ra o, l'estudi es divideix en dos parts principals: primer es revisa la bibliogra a sobre el tema, centrant l'atenci o en dos estrat egies que permeten evitar els principals problemes evocats en la literatura, determinant el seu potencial per a la reducci o de les emissions contaminants. En un segon lloc, es realitza un estudi m es profund dels processos de combusti o i de formaci o de contaminants, centrant-se unicament en les estrat egies de combusti o parcialment premesclada que si que tenen el potencial per a reduir les emissions contaminants. En la segona part de l'estudi, s'aborda l'associaci o de combustions premesclada i per difusi o junt amb la variaci o de par ametres de calibratge convencionals com la concentraci o d'oxigen en l'admissi o (per mitj a de recirculaci o dels gasos d'escapament), la pressi o de sobrealimentaci o i l'inici de la injecci o principal, en diferents condicions de r egim i de c arrega del motor. L'an alisi creuat dels resultats es realitza amb l'afany d'entendre les raons claus dels processos que permeten la reducci o de les emissions contaminants amb esta estrat egia. Com a etapa final d'esta tesi, es confronten les estrat egies de combusti o parcialment premesclada estudiades amb els problemes als quals podrien portar si realment es consideraria la seua implementaci o en un motor de s erie (diluci o d'oli, soroll...) per a finalment concloure sobre el seu potencial tecnol ogic.
Arthozoul, SJL. (2016). Study of the association of premixed and diffusive combustion processes on the combustion and pollutant emissions in a mid-size Diesel engine [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63262
TESIS
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Strålin, Per. "Lagrangian CFD Modeling of Impinging Diesel Sprays for DI HCCI." Doctoral thesis, KTH, Maskinkonstruktion (Avd.), 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4481.
Повний текст джерелаАнотація:
The homogeneous charge compression ignition (HCCI) concept has been acknowledged as a potential combustion concept for engines, due to low NOx and soot emissions and high efficiency, especially at part-load. Early direct-injection (DI) during the compression stroke is an option when Diesel fuel is used in HCCI. This implies that the risk for wall impingement increases, due to the decreasing in-cylinder density. The fuel sprays has to be well dispersed in order to avoid wall impingement. Specially designed impinging nozzles providing a collision of the Diesel sprays in the vicinity of the orifice exits have experimentally been verified to yield well dispersed sprays and the desired benefits of HCCI under various conditions. The purpose of this work is to use Computational Fluid Dynamics (CFD) as a tool to simulate and evaluate non-impinging and impinging nozzles with respect to mixture formation in direct-injected HCCI. Three different nozzles are considered: one non-impinging and two impinging nozzles with 30 and 60 degree collision angle respectively. Lagrangian CFD simulations of impinging sprays using the traditional collision model of O’Rourke is not sufficient in order obtain the correct spray properties of impinging sprays. This work proposes an enhanced collision model, which is an extension of the O’Rourke model with respect to collision frequency, post collisional velocities and collision induced break-up. The enhanced model is referred to as the EORIS model (Enhanced O’Rourke model for Impinging Sprays). The initial drop size distribution at orifice and break-up time constant of the standard Wave model is calibrated and calculated wall impingement (piston and liner) is compared with combustion efficiency, smoke, HC and CO emissions as a function of injection timing. A set of model parameters were selected for further evaluation. These model parameters and the EORIS collision model were applied to non-impinging and impinging nozzles under low- and high load conditions. The EORIS model and the selected model parameters are able to predict wall impingement in agreement with experimental measurements of combustion efficiency and smoke emissions under low- and high load conditions for the investigated nozzles. A benefit is that one set of model parameters can be used to predict mixture formation, and there is no need for additional model calibration when, for instance, the injection timing or nozzle geometry is changed. In general, experiments and simulations indicate that impinging nozzles are recommended for early injection timing in the compression stroke. This is due to the shorter penetration which leads to a reduced risk for wall impingement. The non-impinging nozzles are, however, beneficial for later injection timing in the compression stroke. During these injection conditions the impinging nozzles have a more stratified charge and under some conditions poor mixture quality is achieved.HCCI-konceptet (Homogeneous Charge Compression Ignition) är en tänkbar förbränningsprincip för att uppnå låga NOx och sotemissioner, speciellt under låglast förhållanden. Då Diesel används som bränsle är tidig direktinsprutning under kompressionsslaget en tänkbar strategi för att åstadkomma gynnsamma HCCI-förhållanden. Den tidiga direktinsprutningen medför däremot att risken för väggvätning ökar, på grund av den minskade densiteten i cylindern. Detta ställer krav på bränslesprejen som måste vara väl fördelad i cylindern för att undvika väggvätning. Specialkonstruerade spridarspetsar som skapar kollision av sprejerna nära hålmynningen, så kallade kolliderande sprejer, har experimentellt påvisats vara fördelaktiga för HCCI förbränning, tack vare kortare sprejpenetration och voluminös sprej. Syftet med detta arbete är att använda CFD (Computational FluidDynamics) som ett verktyg för att simulera och evaluera ickekolliderande och kolliderande sprejer med avseende på blandningsbildning under direktinsprutade HCCI förhållanden. Tre olika spridarspetsar har undersökts: en icke-kolliderande och två kolliderande med kollisionsvinkel 30 och 60 grader. CFD-simuleringar av kolliderande sprejer med Lagrangiansk modelleringsteknik och O’Rourkes traditionella kollisionsmodell har visat sig vara otillräcklig för att uppnå korrekta sprejegenskaper. Den här avhandlingen presenterar en förbättrad kollisionsmodell baserad på O’Rourkes ursprungliga kollisionsmodell med avseende på kollisionsfrekvens, dropphastighet efter kollision och kollisionsviinducerad break-up. Den förbättrade modellen kallas EORIS (Enhanced O’Rourke model for Impinging Sprays). Den initiala droppfördelningen vid spridarspetsens hålmynning och Wave-modellens tidskonstant för break-up har kalibrerats och beräknad väggvätning (kolv och foder) har jämförts med förbränningsverkningsgrad, rök, HC och CO-emissioner som funktion av insprutningstidpunkt. De valda modellparametrarna och EORIS-modellen tillämpades för att evaluera blandningsbildningen på kolliderande och icke-kolliderande spridarspetsar under låg- och höglast-förhållanden. EORIS-modellen och de utvalda modellparametrarna kan predikteraväggvätning i överensstämmelse med uppmätt förbränningsverkningsgrad och rökemissioner under låglast- och höglastförhållanden för de undersökta spridarspetsarna. En fördel är att de utvalda modellparametrarna kan prediktera blandningsbildningen och det finns inget behov att justera modellparametrarna då t.ex. insprutningstidpunkten eller spridarspetsgeometrin ändras. Generellt påvisar såväl experiment som simuleringar att de kolliderande sprejerna är lämpliga för tidig direktinsprutning underkompressionsslaget. Det är på grund av kort sprejpenetration som reducerar risken för väggvätning. De icke-kolliderande sprejerna är dock lämpliga för sen direktinsprutning under kompressionsslaget. Under dessa förhållanden har de kolliderande sprejerna en mer stratifierad blandning och under vissa förhållanden uppnås då en ofördelaktig blandningskvalitet.
QC 20100819
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Krige, Jacobus Edmund Joubert. "Endoscopic injection sclerotherapy in the treatment of bleeding oesophageal varices in patients with portal hypertension due to alcohol-induced cirrhosis : an assessment of acute control of bleeding and prognostic factors predicting early variceal re." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/3412.
Повний текст джерела
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Krige, J. E. J. "Endoscopic injection sclerotherapy in the treatment of bleeding oesophageal varices in patients with portal hypertension due to alcohol-induced cirrhosis : an assessment of acute control of bleeding, prevention of recurrent bleeding and prognostic factors predicting early variceal rebleeding and death." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/22099.
Повний текст джерелаАнотація:
The ideal treatment of portal hypertension and bleeding varices should be universally effective, safe, easy to administer and inexpensive. Currently no such treatment exists and the surgeon or physician is obliged to select the most appropriate intervention from a menu of currently available therapeutic options, none of which is ideal or applicable to all patients. The rational treatment of oesophageal varices depends on a clear understanding of the risks of rebleeding and the response to each specific intervention. The selection of the correct and appropriate intervention is critical and requires a comprehensive understanding of the relative efficacy and safety of each treatment compared to other competing options. In addition, the chosen intervention requires detailed knowledge of the criteria underpinning the correct selection of patients for treatment in order to maximize the therapeutic benefits of the appropriate choice while minimising the side effects of the treatment. The optimal management of bleeding oesophageal varices therefore requires a full appreciation of portal, gastric and oesophageal venous collateral anatomy, the pathogenesis and haemodynamic consequences of variceal bleeding and the utility of each available therapy at specific stages in the natural history of portal hypertension (Henderson 1998).
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Karmakar, Shyamal [Verfasser], Martin [Akademischer Betreuer] [Gutachter] Sauter, Iulia [Gutachter] Ghergut, and Gunter [Gutachter] Buntebarth. "Single-well tracer push-pull method development for subsurface process characterization : Early-time tracer injection-flowback test for stimulated fracture characterization, numerical simulation uses and efficiency for flow and solute transport / Shyamal Karmakar ; Gutachter: Martin Sauter, Iulia Ghergut, Gunter Buntebarth ; Betreuer: Martin Sauter." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2016. http://d-nb.info/1121302815/34.
Повний текст джерела
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Oblette, Antoine. "Spermatogenèse in vitro chez la souris : impact sur la qualité nucléaire du spermatozoïde, sur le développement et l'épigénétique de l'embryon issu d'ICSI." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMR004.
Повний текст джерелаАнотація:
Depuis quelques années, une biopsie testiculaire suivie d’une congélation du tissu testiculaire est proposée aux enfants atteints de cancer avant introduction d’un traitement gonadotoxique. Cette procédure de préservation de la fertilité est proposée avec l’espoir qu’une méthode de restauration de la fertilité soit développée. Le tissu testiculaire décongelé pourrait ainsi être utilisé afin d’effectuer une maturation in vitro, évitant la réintroduction de cellules tumorales, pour produire des spermatozoïdes. Ce travail de thèse a consisté, dans un premier temps, à évaluer la mise en place de la méthylation de l’ADN au sein du tissu testiculaire prépubère de souris au cours de la spermatogenèse in vitro. La culture de tissu testiculaire frais ou décongelé de souris prépubère permet le maintien des niveaux d’expression des ADN méthyltransférases 1 et 3a dans les spermatogonies et les spermatocytes. De plus, la méthylation de l’ADN est retrouvée jusque dans les spermatozoïdes produits in vitro. Par la suite, la qualité nucléaire des spermatozoïdes ainsi obtenus a été analysée. La culture de tissu testiculaire n’a pas d’impact sur le taux d’aneuploïdie, la condensation de la chromatine et la fragmentation de l’ADN spermatique. Cependant, la congélation suivie par la culture organotypique augmente la proportion de spermatozoïdes avec un ADN oxydé. Enfin, la fonctionnalité des spermatozoïdes produits in vitro a été analysée par micro-injection ovocytaire et la dynamique de différentes marques épigénétiques a été étudiée au cours du développement préimplantatoire. Les taux de développement embryonnaire sont diminués par l’utilisation de spermatozoïdes produits in vitro. Les niveaux des histones H3K4me3, H3K27me3 et H3K9ac sont peu modifiés dans les embryons issus de spermatozoïdes générés in vitro alors que la méthylation et déméthylation de l’ADN sont plus impactées. La production de spermatozoïdes après culture de tissu prépubère frais ou décongelé dans le modèle murin a permis de mettre en évidence que cette procédure n’est pas sans impact sur l’embryon précoce bien que la qualité des spermatozoïdes produits soit peu altéréeIn recent years, testicular biopsy followed by the freezing of testicular tissue has been proposed to children with cancer before the introduction of a gonadotoxic treatment. This fertility preservation procedure is offered with the hope that a fertility restoration method will be developed. The thawed testicular tissue could thus be used to perform in vitro maturation, avoiding the reintroduction of tumor cells, to produce spermatozoa. This thesis work first consisted in assessing the establishment of DNA methylation in mouse prepubertal testicular tissue during in vitro spermatogenesis. The culture of fresh or thawed mouse testicular testicular tissue allows the expression levels of DNA methyltransferases 1 and 3a to be maintained in spermatogonia and spermatocytes. In addition, DNA methylation is found even in in vitro produced spermatozoa. The nuclear quality of these spermatozoa was then analyzed. The culture of testicular tissue has no impact on sperm aneuploidy rate, chromatin condensation and DNA fragmentation. However, freezing followed by organotypic culture increases the proportion of spermatozoa with oxidized DNA. Finally, the functionality of in vitro produced spermatozoa was analyzed by oocyte microinjection and the dynamics of different epigenetic marks was studied during preimplantation development. Embryo developmental rates are decreased when using in vitro produced spermatozoa. The levels of H3K4me3, H3K27me3 and H3K9ac are slightly modified in embryos derived from spermatozoa generated in vitro whereas DNA methylation and demethylation are more affected. The production of spermatozoa after culture of fresh or thawed prepubertal tissue in the mouse model has shown that this procedure is not without impact on the early embryo, although the quality of the spermatozoa produced is relatively unaltered
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Titjen, Jeremy Quentin. "Tertiary limestones and sedimentary dykes on Chatham Islands, southwest Pacific Ocean, New Zealand." The University of Waikato, 2007. http://hdl.handle.net/10289/2411.
Повний текст джерелаАнотація:
The Chatham Islands are located in the SW Pacific Ocean, approximately 850 km to the east of the South Island of New Zealand. This small group of islands is situated near the eastern margin of the Chatham Rise, an elongated section of submerged continental crust that represents part of the Late Paleozoic-Mesozoic Gondwana accretionary margin. The location and much of the geology of the Chatham Islands are attributed to intra-plate basaltic volcanism, initiated during the Late Cretaceous, in association with development of a failed rifting system to the south of the Chatham Rise. Despite the volcanic nature of much of the geology, the majority of the Cenozoic sedimentary stratigraphic record on the islands comprises non-tropical skeletal carbonate deposits whose deposition was often coeval with submarine volcanics and volcaniclastic deposits. This has resulted in complex stratigraphic relationships, with the volcanic geology exerting a strong influence on the geometry and distribution of the carbonate deposits. These limestones, despite some general field descriptions, have been little studied and are especially poorly understood from a petrographic and diagenetic perspective. The carbonate geology in detail comprises eleven discrete limestone units of Late Cretaceous through to Pleistocene age which were studied during two consecutive field expeditions over the summers of 2005 and 2006. These limestone occurrences are best exposed in scattered coastal outcrops where they form prominent rugged bluffs. While many of the younger (Oligocene to Pliocene) outcrops comprise of poorly exposed, thin and eroded limestone remnants (it;5 m thick), older (Late Paleocene to Early Oligocene) exposures can be up to 100 m in thickness. The character of these limestones is highly variable. In outcrop they display a broad range of textures and skeletal compositions, often exhibit cross-bedding, display differing degrees of porosity occlusion by cementation, and may include rare silicified horizons and evidence of hardground formation. Petrographically the limestones are skeletal grainstones and packstones with a typical compositional makeup of about 70% skeletal material, 10% siliciclasts, and 20% cement/matrix. Localised increases in siliciclastics occur where the carbonates are diluted by locally-derived volcaniclastics. The spectrum of skeletal assemblages identified within the Chatham Island limestones is diverse and appears in many cases to be comparable to the bryozoan dominant types common in mainland New Zealand and mid-latitude Australian cool-water carbonates in general. However, some key departures from the expected cool-water carbonate skeletal makeup have been identified in this study. The occurrence of stromatolitic algal mats in Late Cretaceous and Early Eocene carbonate deposits indicates not cool-temperate, but certainly warm-temperate paleoclimatic conditions. A change to cool-temperate conditions is recorded in the limestone flora/fauna from the mid-Late Miocene times following the development and later northward movement of the Subtropical Front. An uncharacteristic mix of shallow-shelf (bryozoans) and deeper water fauna (planktic foraminifera), together with their highly fragmented and abraded nature, is indicative of the likely remobilisation and redistribution of carbonate, primarily during episodic storm events. The Chatham Islands limestones formed within the relative tectonic stability of an oceanic island setting, which was conducive to ongoing carbonate accumulation throughout much of the Cenozoic. This contrasts markedly with other mainland New Zealand shelf carbonates which formed over sporadic and short-lived geological periods, experiencing greater degrees of burial cementation controlled by a relatively more active tectonic setting. As a consequence of the tectonically stable setting, the Chatham Islands limestones have experienced little burial and exhibit a paucity of burial cementation effects. They remain commonly soft and friable. Detailed petrographic investigations have shown the limestones are variably cemented by rare uneven acicular spar fringes, poorly to well-developed syntaxial rim cements about echinoderm fragments, and equant/blocky microsparite. Staining of thin sections and cathodoluminescence petrography show these spar cement generations are non-ferroan and their very dull- to non-luminescent nature supports precipitation from Mn-poor oxygenated waters, likely of an either meteoric or combined marine/shallow burial origin. Micrite is the dominant intra- and inter-particle pore fill and occurs both as a microbioclastic matrix and as precipitated homogenous and/or micropeloidal cement. The rare fringing cements often seen in association with homogenous and/or micropeloidal micrite may be indicative of true early marine (seafloor) cement precipitation and localised hardground development. An interesting feature of the geology of the Chatham Islands is the occurrence of carbonate material within sedimentary dykes. The locations of the dykes are in association with volcanic and volcaniclastic deposits. Similarities between dyke characteristics at Red Bluff on Chatham Island with mainland occurrences from East Coast and Canterbury Basins (North and South Islands, respectively) on mainland New Zealand have been recognised. They show complex structures including sidewall striations, internal flow structures as revealed by grain sorting, and extra-clast inclusions of previous fill lithologies which are characteristic of carbonate injection. This is in contrast to other dykes which are known to be of a passive fill origin. Multiple phases of carbonate sediment injection can be recognised by crosscutting relationships enabling the determination of a parasequence of events. Possible injection mechanisms are most likely associated with sediment overloading or hydrothermal pressurisation associated with emplacement of submarine volcanics. The Chatham Islands provide an exciting example of a geologically unique and complex non-tropical carbonate depositional setting. The production of carbonates is controlled by volcanic and volcaniclastic sediment input with the types of carbonate deposits and water depth variations related to thermal uplift/subsidence in association with global eustatic sealevel and temperature changes associated with development of Southern Ocean water fronts from the Late Cretaceous-Cenozoic. Carbonate deposition on the Chatham Islands is considered to relate to a rather variable and small scale oceanic, high energy, cool-water carbonate ramp setting whose geometry was continually evolving/changing as a consequence of periodic volcanic episodes.
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Bower, Glenn Robert. "The effect of a split injection on early combustion in an engine-fed combustion chamber." 1992. http://catalog.hathitrust.org/api/volumes/oclc/28704287.html.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--University of Wisconsin--Madison, 1992.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 110-114).
Книги з теми "Early injection"
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Dacome, Lucia. Injecting Knowledge. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198736189.003.0008.
Повний текст джерелаАнотація:
Chapter 7 furthers the analysis of the role of anatomical models as cultural currencies capable of transferring value. It does so by expanding the investigation of the early stages of anatomical modelling to include a new setting. In particular, it follows the journey of the Palermitan anatomist and modeller Giuseppe Salerno and his anatomical ‘skeleton’—a specimen that represented the body’s complex web of blood vessels and was presented as the result of anatomical injections. Although Salerno was headed towards Bologna, a major centre of anatomical modelling, he ended his journey in Naples after the nobleman Raimondo di Sangro purchased the skeleton for his own cabinet of curiosities. This chapter considers the creation and viewing of an anatomical display in di Sangro’s Neapolitan Palace from a comparative perspective that highlights how geography and locality played an important part in shaping the culture of mid-eighteenth-century anatomical modelling.
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Barnett, Ben J., and Margaret Hoffman-Terry. HIV/Hepatitis Co-infection. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190493097.003.0039.
Повний текст джерелаАнотація:
Hepatitis B virus (HBV) infection is common in people living with HIV, and all patients with HIV should be screened for HBV infection. The most common route of transmission worldwide is through perinatal or early childhood exposure, but adult transmission of HBV is often by routes similar to those for HIV, including sexual contact and injection drug use. Although it varies by exposure route, approximately 10% of HIV-positive patients also have chronic HBV infection, and up to 90% have serologic evidence of past exposure to HBV. Long-term complications of HBV infection can include cirrhosis, end-stage liver disease, and hepatocellular carcinoma.
3
Clark, David. Hospice and Palliative Care. Edited by Stuart J. Youngner and Robert M. Arnold. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780199974412.013.4.
Повний текст джерелаАнотація:
Hospice and palliative care have shared but divergent histories. By the early 20th century, a new focus on end-of-life care had also appeared. Despite a lack of definitional precision within these models, there is a fragile but emergent evidence base and a growing professionalization of the field. As awareness increases about the rising number of deaths in the world, competing claims also emerge about the manner of our dying. These go beyond the field itself to include support for assisted dying, greater emphasis on community resilience in the face of aging and death, plus growing environmental awareness of the significance of rising death rates. These require interdisciplinary thinking, as well the injection of new ideas from cognate fields in the health and social sciences.
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Hiltebeitel, Alf. Thinking Goddesses, Mothers, Brothers, and Snakes with Freud and Bose. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190878375.003.0008.
Повний текст джерелаАнотація:
This chapter further explores snake symbolism, highlighting also goddesses, Freud’s mother Amalia, and Freud’s brothers and half-brothers. The author considers the ideas of post-Freudian psychoanalytic writers who shed light on these themes, including Eric Erikson, and Freud’s “specimen dream” of “Irma’s Injection” as evoking a vagina. Here, Freud states his rule that every dream has an “unplumbable navel” beyond which the analyst cannot go. The chapter goes on to discuss ideas of Bernard This, John Abbott, and Bruno Bettelheim, with Freud’s early mention of the Loch Ness monster as a likely allusion to Athena with her snakes. Finally, the author takes up Bertram Lewin’s concept of the “dream screen,” as well as the personal universe of Romain Rolland’s oceanic feeling.
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Steiner, Lisa A. Infections of the Hand. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199976805.003.0047.
Повний текст джерелаАнотація:
Hand infections can be delineated by type and location of infection, by a polymicrobial vs single microbial colonization, and by the type of organism. They are most often caused by superficial injury or trauma. Early identification and timely treatment can significantly improve the morbidity associated with hand infections. In addition to determining the source and mechanism of infection, it is important to identify tetanus immunization status, prior injury to the affected area, immune status, occupation, and hand dominance. Some hand infections (eg, paronychia, felon, herpetic whitlow, and cellulitis) can be treated in the emergency department and discharged with close follow-up. Deep space abscesses and infections caused by bite wounds involving tendons will require either observation, admission, or surgery depending on their severity. Take into account a patient’s comorbidities—diabetes, immunosuppression, injection drug use, inability to follow up for re-evaluation, and ability to fill antibiotic prescriptions—upon disposition.
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Youngner, Stuart J., and Robert M. Arnold. Introduction. Edited by Stuart J. Youngner and Robert M. Arnold. Oxford University Press, 2015. http://dx.doi.org/10.1093/oxfordhb/9780199974412.013.30.
Повний текст джерелаАнотація:
This volume explores the topic of death and dying from the late twentieth to the early twenty-first centuries, with particular emphasis on the United States. The book comprises six sections. Section I examines how the law has helped shape clinical practice, emphasizing the roles of rights and patient autonomy. Section II focuses on specific clinical issues, including death and dying in children, continuous sedation as a way to relieve suffering at the end of life, and the problem of prognostication in patients who are thought to be dying. Section III considers psychosocial and cultural issues, Section IV discusses death and dying among various vulnerable populations such as the elderly and persons with disabilities, and Section V deals with physician-assisted suicide and active euthanasia (lethal injection). Finally, Section VI looks at hospice and palliative care as a way to address the psychosocial and ethical problems of death and dying.
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Mohamed, Mahmood Nazar, Hassan Ali, Faisal Ibrahim, and Ahamad Jusoh. Estimation of drug users and injecting drug users in Malaysia. UUM Press, 2005. http://dx.doi.org/10.32890/9833282415.
Повний текст джерелаАнотація:
Malaysia treats the problem of drug addiction as a security issue. Since it was identified in the early 70s, the number of drug addicts is constantly on the rise. At present, the government provides all statistics pertaining to the number of drug users, abusers and addicts in the country.The monograph contains the full report that was submitted to the Ministry of Health and WHO-WPR. It reports the national data for drug addiction for the year 2002, and a detailed description of the methodology used to arrive at the estimates.
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Kane, David, and Philip Platt. Ultrasound. Oxford University Press, 2013. http://dx.doi.org/10.1093/med/9780199642489.003.0067.
Повний текст джерелаАнотація:
Musculoskeletal ultrasound (MSUS) is rapidly becoming a standard part of many rheumatologists' daily clinical practice. MSUS is safe, increasingly widely available, relatively low cost, non-invasive, and hence very acceptable to the patient. Current problems with availability of training, mentoring, and accreditation procedures need to be overcome for MSUS to reach its full potential for rheumatologists. MSUS is capable of improving clinical diagnosis and the accuracy of intervention. MSUS is more sensitive than clinical examination in the detection of synovitis and effusion and is capable of rapid targeted assessment of widely spaced joints coupled with clinical correlation. MSUS has advantages over other imaging modalities; the ability to display dynamic real-time movement makes it the imaging modality of choice for tendon problems. It is significantly more sensitive than plain radiology in the demonstration of early erosive changes, and although its sensitivity is less than that of MRI for the detection of erosions it is far more practical, timely, and available. The combination of sensitivity in detection of synovitis, tenosynovitis, and erosions makes it an ideal imaging modality in the context of an early arthritis clinic. Power Doppler has been shown to be an effective way of evaluating synovitis and hence is of value in early diagnosis and monitoring of inflammatory arthritides. The accuracy of placement of local injection therapies is enhanced by MSUS, and it significantly increases the diagnostic success rate of aspiration of joints and bursas. The flexibility of ultrasound as a tool for rheumatologists is shown by its application in the assessment of vasculitides, peripheral nerve pathology, salivary glands, and skin lesions.
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Kane, David, and Philip Platt. Ultrasound. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199642489.003.0067_update_002.
Повний текст джерелаАнотація:
Musculoskeletal ultrasound (MSUS) is rapidly becoming a standard part of many rheumatologists’ daily clinical practice. MSUS is safe, increasingly widely available, relatively low cost, non-invasive, and hence very acceptable to the patient. Current problems with availability of training, mentoring, and accreditation procedures need to be overcome for MSUS to reach its full potential for rheumatologists. MSUS is capable of improving clinical diagnosis and the accuracy of intervention. MSUS is more sensitive than clinical examination in the detection of synovitis and effusion and is capable of rapid targeted assessment of widely spaced joints coupled with clinical correlation. MSUS has advantages over other imaging modalities; the ability to display dynamic real-time movement makes it the imaging modality of choice for tendon problems. It is significantly more sensitive than plain radiology in the demonstration of early erosive changes, and although its sensitivity is less than that of MRI for the detection of erosions it is far more practical, timely, and available. The combination of sensitivity in detection of synovitis, tenosynovitis, and erosions makes it an ideal imaging modality in the context of an early arthritis clinic. Power Doppler has been shown to be an effective way of evaluating synovitis and hence is of value in early diagnosis and monitoring of inflammatory arthritides. The accuracy of placement of local injection therapies is enhanced by MSUS, and it significantly increases the diagnostic success rate of aspiration of joints and bursas. The flexibility of ultrasound as a tool for rheumatologists is shown by its application in the assessment of vasculitides, peripheral nerve pathology, salivary glands, and skin lesions.
10
Sugiyama, Masahiro, Atsushi Ishii, Shinichiro Asayama, and Takanobu Kosugi. Solar Geoengineering Governance. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.647.
Повний текст джерелаАнотація:
Climate engineering, a set of techniques proposed to intervene directly in the climate system to reduce risks from climate change, presents many novel governance challenges. Solar radiation management (SRM), particularly the use of stratospheric aerosol injection (SAI), is one of the most discussed proposals. It has been attracting more and more interest, and its pertinence as a potential option for responding to the threats from climate change may be set to increase because of the long-term temperature goal (well below 2°C or 1.5°C) in the 2015 Paris Agreement. Initial research has demonstrated that SAI would cool the climate system and reduce climate risks in many ways, although it is mired in unknown environmental risks and various sociopolitical ramifications. The proposed techniques are in the early stage of research and development (R&D), providing a unique opportunity for upstream public engagement, long touted as a desirable pathway to more plural and inclusive governance of emergent technologies by opening up social choices in technology. Solar geoengineering governance faces various challenges. One of the most acute of these is how to situate public engagement in international governance discourse; the two topics have been studied separately. Another challenge relates to bridging the gap between the social choices at hand and assessment of the risks and benefits of SRM. Deeper integration of knowledge across disciplines and stakeholder and public inputs is a prerequisite for enabling responsible innovation for the future of our climate.
Частини книг з теми "Early injection"
1
Filardo, Giuseppe, Giorgio di Laura Frattura, Davide Previtali, Angelo Boffa, and Christian Candrian. "Role of Injection Therapy in Early Osteoarthritis: Cortisone, Viscosupplement, PRP?" In Early Osteoarthritis, 197–206. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-79485-9_14.
Повний текст джерела
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Rubio, Alfonso Delgado, and Fabio Arcangeli. "A Child with High Fever, Rash, Chapped Lips and Conjunctival Injection." In Clinical Cases in Early-Years Pediatric Dermatology, 7–11. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-89089-6_2.
Повний текст джерела
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Li, Qi, Xiaochun Li, Lei Du, Guizhen Liu, Xuehao Liu, and Ning Wei. "Potential Sites and Early Opportunities of Acid Gas Re-injection in China." In Sour Gas and Related Technologies, 129–42. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118511138.ch9.
Повний текст джерела
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Juez, Garazi, Estíbaliz Amparan, Ray Lattarulo, Alejandra Ruíz, Joshué Pérez, and Huáscar Espinoza. "Early Safety Assessment of Automotive Systems Using Sabotage Simulation-Based Fault Injection Framework." In Lecture Notes in Computer Science, 255–69. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-66266-4_17.
Повний текст джерела
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Mori, Kentaro, Masahiro Miyazaki, Yasukazu Hara, Yasuhisa Aiko, Takuji Yamamoto, Yasuaki Nakao, and Takanori Esaki. "Temporal Profile of the Effects of Intracisternal Injection of Magnesium Sulfate Solution on Vasodilation of Spastic Cerebral Arteries in the Canine SAH Model." In Early Brain Injury or Cerebral Vasospasm, 39–42. Vienna: Springer Vienna, 2011. http://dx.doi.org/10.1007/978-3-7091-0356-2_8.
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Rana, Rakesh, Miroslaw Staron, Christian Berger, Jörgen Hansson, Martin Nilsson, and Fredrik Törner. "Early Verification and Validation According to ISO 26262 by Combining Fault Injection and Mutation Testing." In Communications in Computer and Information Science, 164–79. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-45943-0_11.
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Harima, Aki, Jan Harima, and Jörg Freiling. "The injection of resources by transnational entrepreneurs:towards a model of the early evolution of an entrepreneurial ecosystem." In The Dynamics of Entrepreneurial Ecosystems, 102–29. London: Routledge, 2021. http://dx.doi.org/10.4324/9781003244967-6.
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Bhave, Nikhil Aniruddha, Mahendra M. Gupta, Sandeep S. Joshi, and Sushant S. Satputaley. "Effect of Varying Flowrate of Oxy-hydrogen (HHO) Gas Addition on Combustion and Emission Characteristics of Early Direct Injection Homogenous Charge Compression Ignition Engine." In Lecture Notes in Mechanical Engineering, 141–51. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-3410-0_12.
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Reznikoff-Etievant, M. F., I. Durieux, J. Huchet, C. Salmon, and A. Netter. "Human MHC antigens and paternal leucocyte injections in recurrent spontaneous abortions." In Early Pregnancy Loss, 375–84. London: Springer London, 1988. http://dx.doi.org/10.1007/978-1-4471-1658-5_52.
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Taisne, Benoit, Anna Perttu, Dorianne Tailpied, Corentin Caudron, and Luca Simonini. "Atmospheric Controls on Ground- and Space-Based Remote Detection of Volcanic Ash Injection into the Atmosphere, and Link to Early Warning Systems for Aviation Hazard Mitigation." In Infrasound Monitoring for Atmospheric Studies, 1079–105. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-75140-5_34.
Повний текст джерелаТези доповідей конференцій з теми "Early injection"
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Kim, Manshik, Rolf D. Reitz, and Song-Charng Kong. "Modeling Early Injection Processes in HSDI Diesel Engines." In SAE 2006 World Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2006. http://dx.doi.org/10.4271/2006-01-0056.
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Jhavar, Rahul, and Christopher J. Rutland. "Effects of Mixing on Early Injection Diesel Combustion." In SAE 2005 World Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2005. http://dx.doi.org/10.4271/2005-01-0154.
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André, M., B. Walter, G. Bruneaux, F. Foucher, and C. Mounaim-Rousselle. "Optimizing Early Injection Strategy for Diesel PCCI Combustion." In SAE 2009 Powertrains Fuels and Lubricants Meeting. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2009. http://dx.doi.org/10.4271/2009-01-2731.
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Kim, Yungjin, Sangki Park, and Kihyung Lee. "Investigation of the Optimal Injection Conditions for a PCCI Diesel Engine." In ASME 2012 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icef2012-92178.
Повний текст джерелаАнотація:
Premixed charge compression ignition (PCCI) engines have the potential with their attractive advanced combustion process to achieve a more homogeneous mixture and a lower peak combustion temperature resulting in both lower nitrogen oxides (NOx) and diesel particulate matter (PM) emissions. In this study, the spray characteristics for a PCCI engine according to various injection conditions were introduced and then the effects of injection strategies such as injection angles, injection timings and times on combustion and emissions were studied for a single cylinder PCCI engine using early multiple injections first. Add more, a method of early-main type split injection was used for a 4-cylinder PCCI engine and the effects of injection conditions on the combustion and emission characteristics were investigated. Finally flame visualization tests were performed to validate the result obtained from the engine test. The experimental results showed that the mixture formation, indicated mean effective pressure (IMEP), and emission characteristics were dominantly affected by the injection conditions and the multiple injection method resulted in higher IMEP and still low smoke level characteristics. It appeared that more homogeneous mixture could be formed with decreasing of spray penetration and increasing of fuel evaporation rate for the early multiple injections. In case of the split injection, both injection timing and injected fuel ratio of the early and main injection largely affected engine combustion and emission characteristics. From the results, as the early injection rate increased premixed combustion was activated, on the other hand, as the main injection rate increased conventional diesel combustion was activated, therefore suitable split injection conditions could be selected for the 4-cylinder PCCI engine.
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Michailidis, A. D., R. K. Stobart, and G. P. McTaggart-Cowan. "Fuel-Line Stationary Waves and Variability in CI Combustion During Complex Injection Strategies." In ASME 2010 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/icef2010-35069.
Повний текст джерелаАнотація:
This study investigated the effects of increased injection regime complexity on injector and combustion stability in a naturally aspirated single cylinder diesel engine equipped with a common rail fuel injection system and an instrumented injector. The injection regimes investigated included a single injection, a main injection with a pilot, and a split-main with a pilot. Injector performance was found to be very stable over all injection regimes and did not contribute to variations in combustion stability. Cylinder pressure variation during the initiation of combustion was identified as a potential method of identifying the start of combustion phasing and compared to current methods. Three series of tests were conducted at various speeds and injection pressures to demonstrate the influence of multi-pulse injection phasing on combustion stability and total fuel consumption. These results demonstrate that the presence of a stationary wave in the high-pressure fuel line, induced by an early injection, can dramatically affect the amount of fuel injected in subsequent injections within the same cycle.
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Kanda, Tomohiro, Takazo Hakozaki, Tatsuya Uchimoto, Jyunichi Hatano, Naoto Kitayama, and Hiroshi Sono. "PCCI Operation with Early Injection of Conventional Diesel Fuel." In SAE 2005 World Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2005. http://dx.doi.org/10.4271/2005-01-0378.
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Greener, James. "An Act of Particular Providence - Newcomen’s Speedy Vacuum." In 2nd International Early Engines Conference. International Early Engines Conference & ISSES, 2021. http://dx.doi.org/10.54267/ieec2-1-02.
Повний текст джерелаАнотація:
Comparison of the only known account of the invention of cold water injection to activate an atmospheric engine with contemporary texts on experimental methodology reveals that Newcomen and Calley’s inventive process corresponds with the design of experiments prescribed by Robert Hooke for the Royal Society. Consequently, when an unexpected outcome occurred, they were able to make full application of the findings. Differences between the steam piston experiments of Newcomen and Denis Papin are explored, suggesting that the inventors may have been working in parallel.
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Asad, Usman, and Ming Zheng. "Evaluation of Diesel Low Temperature Combustion Fuel-Injection Strategies at Different Engine Loads." In ASME 2010 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/icef2010-35172.
Повний текст джерелаАнотація:
High hydrocarbon levels in the exhaust, increased cycle-to-cycle variation and reduced energy-efficiency are typical problems associated with diesel LTC operation. To overcome these challenges, three different fuel injection strategies (late single-injection, early multiple-injections and split-injections) have been investigated on a modified single cylinder common-rail diesel engine. The effects of EGR, boost and injection pressure on the emissions and combustion efficiency have been analyzed. The effect of heavy EGR has been quantified in terms of a trade-off between the combustion phasing and the combustion efficiency. To minimize fuel condensation and wall-wetting with early injections, a criterion for selecting the earliest timing for injection during the compression stroke has also been evaluated. This research is concluded with the formulation of a load management strategy to enable energy-efficient diesel LTC up to 10 bar IMEP.
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De Vita, A., L. Di Angelo, and L. Allocca. "Early-Injection and Time-Resolved Evolution of a Spray for GDI Engines." In ASME 2002 Joint U.S.-European Fluids Engineering Division Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/fedsm2002-31165.
Повний текст джерелаАнотація:
An extensive experimental study on sprays from an injector for gasoline direct injection (GDI) engines has been performed. Spatial and temporal evolution measurements of a large cone-angle jet, emerging from a high pressure swirled injector, have been carried out in an optically accessible vessel. The spray has been lightened, both along the spray axis and in cross sections perpendicular to it, by a 532 nm Nd-YAG pulsed laser sheet, 80 mm thickness and 12 ns duration. The scattered light has been collected at 90° with respect to the sheet direction by a digital CCD camera with a frame grabber synchronized with the injection command and the laser pulse. A digital delay system has provided a fine temporal shift (up to microseconds range) of the images acquisition with respect to the start of the injection (SOI). Finally, a digital image processing system has provided analysing the images collected by the CCD camera. The emerging spray has been acquired with three spatial scales, providing both the global and local spray behaviour, and with a detailed temporal resolution to characterize the early stage of the jet formation. The initial phase of the spray is characterized by a strong axial component of the velocity with respect to the radial one, resulting in a pre-spray or slug phase. It produces a cylindrical shape of the jet with the characteristic mushroom shape. Large droplets with high momentum are produced, travelling downstream in advance to the main spray. At later time the radial velocity component controls the process and it gives up to the classical hollow-cone shape with a strong interaction with the gas in the vessel. The images give evidence in time of the collapse of the hollow-cone structure hence resulting in a full cone spray. This behaviour is confirmed by the cross section measurements through the spray, carried out in the range 10–40 mm from the nozzle tip. These measurements make evidence of the refilling of the cone with the presence of strong vortexes on the boundary of the jet. The effects of the fuel injection pressure, injection duration and air-flow field interaction on the structure and evolution of the spray have been studied in details. The digital image processing system also has allowed to reconstruct the spray profile and to determine a refilling index.
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Nandha, Kannan P., and John Abraham. "Dependence of Fuel-Air Mixing Characteristics on Injection Timing in an Early-Injection Diesel Engine." In SAE 2002 World Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2002. http://dx.doi.org/10.4271/2002-01-0944.
Повний текст джерелаЗвіти організацій з теми "Early injection"
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Hovorka, Susan. SECARB Early Test CO2 Injection and Recycle. Office of Scientific and Technical Information (OSTI), September 2011. http://dx.doi.org/10.2172/1821125.
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Hovorka, Susan. SECARB Early Test Decision Point for CO2 Injection. Office of Scientific and Technical Information (OSTI), September 2008. http://dx.doi.org/10.2172/1821124.
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S.S. Medley, D.S. Darrow, D. Liu, and A.L. Roquemore. Prompt Loss of Energetic Ions during Early Neutral Beam Injection in the National Spherical Torus Experiment. Office of Scientific and Technical Information (OSTI), March 2005. http://dx.doi.org/10.2172/838508.
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Huang, Caixia, Cuiling Huang, and Guomin Zhou. Danhong injection for the treatment of early diabetic nephropathy: a protocol of systematic review and meta-analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, September 2020. http://dx.doi.org/10.37766/inplasy2020.9.0005.
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Koiro, Brenda J. The Effect of the Time of Injection of Intrathecal Analgesia on the Length of Early and Advanced Labor. Fort Belvoir, VA: Defense Technical Information Center, September 1999. http://dx.doi.org/10.21236/ad1012145.
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Meidan, Rina, Jorge Flores, Keith Inskeep, and David Wolfenson. Controlling the bovine ovarian cycle by disrupting the endothelin system in corpora lutea and follicles with novel approaches: RNA interference (RNAi) and intra-luteal Atrigel implants. United States Department of Agriculture, June 2006. http://dx.doi.org/10.32747/2006.7695594.bard.
Повний текст джерелаАнотація:
In summary intensive studies carried out this year in both the US and Israel had established the methodology necessary for the achievement of the specific aims of the original proposal. Two complementary approaches to effectively neutralize the luteal ET- system were developed. In light of recent publications indicating that ET-2 might also have a physiological role in ovulation, the objectives of the original proposal have even more significant. Not only were the technologies to neutralize the luteal endothelin system developed in these studies, but additional important implications about the role of ET-1 were revealed. For example, direct early inhibitory effects of PGF2α were unmasked. It is possible that these early direct inhibitory effects could be related to functional aspects of luteal regression, while the effects observed after 12 hours of the PGF2α injection and that reversed by the ET receptor antagonist, could coincide with structural aspects of regression. Nevertheless, overall, the results clearly indicate that serum progesterone concentrations can effectively be elevated by the receptor antagonist which of great practical importance.
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Fields, Michael J., Mordechai Shemesh, and Anna-Riitta Fuchs. Significance of Oxytocin and Oxytocin Receptors in Bovine Pregnancy. United States Department of Agriculture, August 1994. http://dx.doi.org/10.32747/1994.7568790.bard.
Повний текст джерелаАнотація:
Oxytocin has multiple actions in bovine reproductive tract and it was our purpose to determine the nature of these actions and their significance for the physiology of bovine reproduction. The bovine oxytocin receptors (OTR) gene was cloned and its expression studied during the cycle and pregnancy. OTR mRNA changed in parallel with OTR with control occurring mainly at the transcriptional level. However, the endocrine regulation of OTR were found in endometrium and cervical mucosa at estrus and at parturition. In both tissues OTR were suppressed in the luteal phase and early pregnancy. Whereas cervical OTR remained suppressed throughout pregnancy, endometrial OTR began to increase soon after implantation and reached higher concentrations in midpregnancy than at estrus. OTR in caruncles did not increase until third trimester, and OTR in cervical mucosa, cotyledons and fetal membranes increased only at term. Myometrial OTR showed less variation and OTR were present throughout the cycle and pregnancy but increased significantly during mid- and late pregnancy. OTR were localized in endometrial epithelial cells and lumina epithelial cells of cervical mucosa as determined by immunohistochemistry. Endometrial OTR were functional throughout pregnancy and mediated PGF release from day 50 onwards in a receptor density related manner. OTR in cervical mucosa mediated PGE release both in vivo and in vitro, as shown in cyclic cows. The ontogeny of uterine OTR was studied from third trimester fetal stage until puberty. OTR were present in endometrium and cervical mucosa in high concentrations throughout this period; myometrial OTR began to increase somewhat later but also reached adult values by 6-mo of age. In the prepuberal heifers OT injections failed to initiate PGF2a, release. The influence of steroids on the effect of OT was examined. Ovariectomy and E2 were without effect, but P4 with or without E2 induced a massive PGF2a release in response to OT in spite of reduced OTR. Bovine cyclooxygenases (COX-1 and COX-2) were cloned and their expression studied in the endometrium of prepuberal heifers and pregnant cows. Untreated and E2 treated prepuberal heifers did not express COX-2 but P4 treated heifers did express the mRNA for COX-2, albeit weakly. During the second half of pregnancy COX-2 mRNA was strongly expressed in cotyledons and somewhat less in caruncles, whereas endometrium, myometrium and cervical mucosa showed only weak, if any, COX-2 mRNA under basal conditions. However, 2 h after OT injection significant increases in COX-2 mRNA were found in endometrial RNA. Thus OT is capable of inducing the expression of the inducible COX-2 gene, and hence the conversion of arachidonic acid to prostanoids. The results indicate that the functions of OT are numerous and probably essential for successful pregnancy and parturition.
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Wolfenson, David, William W. Thatcher, and James E. Kinder. Regulation of LH Secretion in the Periovulatory Period as a Strategy to Enhance Ovarian Function and Fertility in Dairy and Beef Cows. United States Department of Agriculture, December 2003. http://dx.doi.org/10.32747/2003.7586458.bard.
Повний текст джерелаАнотація:
The general research objective was to increase herd pregnancy rates by enhancing corpus luteum (CL) function and optimizing follicle development, in order to increase conception rate and embryo survival. The specific objectives were: to determine the effect of the duration of the preovulatory LH surge on CL function; to determine the function of LH during the postovulatory period on CL development; to optimize CL differentiation and follicle development by means of a biodegradable GnRH implant; to test whether optimization of CL development and follicle dynamics in timed- insemination protocols would improve fertility in high-yielding dairy cows. Low fertility in cattle results in losses of hundreds of millions of dollars in the USA and Israel. Two major causes of low fertility are formation of a functionally impaired CL, and subsequent enhanced ovarian follicle development. A functionally impaired CL may result from suboptimal LH secretion. The two major causes of low fertility in dairy cattle in US and Israel are negative energy status and summer heat stress; in both situations, low fertility is associated with reductions in LH secretion and impaired development of the ovulatory follicle and of the CL. In Florida, the use of 450-mg deslorelin (GnRH analogue) implants to induce ovulation, under the Ovsynch protocol resulted in a higher pregnancy rates than use of 750-mg implants, and pregnancy losses tended to decrease compared to controls, due probably to decrease in follicular development and estradiol secretion at the time of conceptus signaling to maintain the CL. An alternative strategy to enhance progesterone concentrations involved induction of an accessory CL by injection of hCG on day 5 after the cows were inseminated. Treatment with hCG resulted in 86% of the cows having two CLs, compared with 23% of the control cows. Conception rates were higher among the hCG-treated cows than among the controls. Another approach was to replace the second injection of GnRH analogue, in a timed-insemination protocol, with estradiol cypionate (ECP) injected 24 h after the injection of PGF₂ₐ Pregnancy rates were comparable with those obtained under the regular Ovsynch (timed- AI) program. Use of ECP induced estrus, and cows inseminated at detected estrus are indeed more fertile than those not in estrus at the time of insemination. Collectively, the BARD-supported programs at the University of Florida have improved timed insemination programs. In Ohio, the importance of the frequency of LH episodes during the early stages of the estrous cycle of cattle, when the corpus luteum is developing, was studied in an in vivo experiment in which cows were subjected to various episodic exposures to exogenous bovine LH. Results indicate that the frequent LH episodes immediately following the time of ovulation are important in development of the corpus luteum, from the points of view of both size and functionality. In another study, rates of cell proliferation and numbers of endothelial cells were examined in vitro in CLs collected from cows that received post-ovulation pulsatile LH treatment at various frequencies. The results indicate that the corpora lutea growth that results from luteal cell proliferation is enhanced by the episodes of LH release that occur immediately after the time of ovulation in cattle. The results also show that luteal endothelial cell numbers did not differ among cows treated with different LH doses. In Israel. a longer duration of the preovulatory LH surge stimulated the steroidogenic capacity of granulosa-derived luteal cells, and might, thereby, contribute to a higher progesterone output from the bovine corpus luteum. In an in vivo study, a subgroup of high-yielding dairy cows with extended estrus to ovulation interval was identified. Associated with this extended interval were: low plasma progesterone and estradiol concentrations and a low preovulatory LH surge prior to ovulation, as well as low post- ovulation progesterone concentration. In experiments based on the above results, we found that injection of GnRH at the onset of estrus increased the LHpeak, prevented late ovulation, decreased the variability between cows and elicited high and uniform progesterone levels after ovulation. GnRH at estrus onset increased conception rates, especially in the summer, and among primiparous cows and those with low body condition. Another study compared ovarian functions in multiparous lactating cows with those in nulliparous non-lactating heifers. The results revealed differences in ovarian follicular dynamics, and in plasma concentrations of steroids and gonadotropins that may account for the differences in fertility between heifers and cows.
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Sabatelle, Jason, Adonis Caramintzos, and Jamie McCall. Small Business COVID-19 Lending Programs: Fostering Social Capital and Financial Stability. Carolina Small Business Development Fund, January 2021. http://dx.doi.org/10.46712/covid.lending.
Повний текст джерелаАнотація:
In times of crisis, investment in entrepreneurial ventures tends to decline. Early data suggest the decline in small business investments due to the pandemic will be historic in scope and depth. Community development lending practices aim to sustain small firms until they can resume their normal course of business. Affordable financing provides capital injections into small businesses which can help to cushion against COVID-19 induced economic shocks. Using Carolina Small Business Development Fund’s lending data as a case study, this analysis considers the effect of COVID-19 response programs. These activities are oriented towards creating a “social safety net” of Main Street businesses that boost social capital development, community trust, and financial stability. We believe the findings are likely generalizable to lending activities by other community development financial institutions.
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Meidan, Rina, and Robert Milvae. Regulation of Bovine Corpus Luteum Function. United States Department of Agriculture, March 1995. http://dx.doi.org/10.32747/1995.7604935.bard.
Повний текст джерелаАнотація:
The main goal of this research plan was to elucidate regulatory mechanisms controlling the development, function of the bovine corpus luteum (CL). The CL contains two different sterodigenic cell types and therefore it was necessary to obtain pure cell population. A system was developed in which granulosa and theca interna cells, isolated from a preovulatory follicle, acquired characteristics typical of large (LL) and small (SL) luteal cells, respectively, as judged by several biochemical and morphological criteria. Experiments were conducted to determine the effects of granulosa cells removal on subsequent CL function, the results obtained support the concept that granulosa cells make a substaintial contribution to the output of progesterone by the cyclic CL but may have a limited role in determining the functional lifespan of the CL. This experimental model was also used to better understand the contribution of follicular granulosa cells to subsequent luteal SCC mRNA expression. The mitochondrial cytochrome side-chain cleavage enzyme (SCC), which converts cholesterol to pregnenolone, is the first and rate-limiting enzyme of the steroidogenic pathway. Experiments were conducted to characterize the gene expression of P450scc in bovine CL. Levels of P450scc mRNA were higher during mid-luteal phase than in either the early or late luteal phases. PGF 2a injection decreased luteal P450scc mRNA in a time-dependent manner; levels were significantly reduced by 2h after treatment. CLs obtained from heifers on day 8 of the estrous cycle which had granulosa cells removed had a 45% reduction in the levels of mRNA for SCC enzymes as well as a 78% reduction in the numbers of LL cells. To characterize SCC expression in each steroidogenic cell type we utilized pure cell populations. Upon luteinization, LL expressed 2-3 fold higher amounts of both SCC enzymes mRNAs than SL. Moreover, eight days after stimulant removal, LL retained their P4 production capacity, expressed P450scc mRNA and contained this protein. In our attempts to establish the in vitro luteinization model, we had to select the prevulatory and pre-gonadotropin surge follicles. The ratio of estradiol:P4 which is often used was unreliable since P4 levels are high in atretic follicles and also in preovulatory post-gonadotropin follicles. We have therefore examined whether oxytocin (OT) levels in follicular fluids could enhance our ability to correctly and easily define follicular status. Based on E2 and OT concentrations in follicular fluids we could more accurately identify follicles that are preovulatory and post gonadotropin surge. Next we studied OT biosynthesis in granulosa cells, cells which were incubated with forskolin contained stores of the precursor indicating that forskolin (which mimics gonadotropin action) is an effective stimulator of OT biosynthesis and release. While studying in vitro luteinization, we noticed that IGF-I induced effects were not identical to those induced by insulin despite the fact that megadoses of insulin were used. This was the first indication that the cells may secrete IGF binding protein(s) which regonize IGFs and not insulin. In a detailed study involving several techniques, we characterized the species of IGF binding proteins secreted by luteal cells. The effects of exogenous polyunsaturated fatty acids and arachidonic acid on the production of P4 and prostanoids by dispersed bovine luteal cells was examined. The addition of eicosapentaenoic acid and arachidonic acid resulted in a dose-dependent reduction in basal and LH-stimulated biosynthesis of P4 and PGI2 and an increase in production of PGF 2a and 5-HETE production. Indomethacin, an inhibitor of arachidonic acid metabolism via the production of 5-HETE was unaffected. Results of these experiments suggest that the inhibitory effect of arachidonic acid on the biosynthesis of luteal P4 is due to either a direct action of arachidonic acid, or its conversion to 5-HETE via the lipoxgenase pathway of metabolism. The detailed and important information gained by the two labs elucidated the mode of action of factors crucially important to the function of the bovine CL. The data indicate that follicular granulosa cells make a major contribution to numbers of large luteal cells, OT and basal P4 production, as well as the content of cytochrome P450 scc. Granulosa-derived large luteal cells have distinct features: when luteinized, the cell no longer possesses LH receptors, its cAMP response is diminished yet P4 synthesis is sustained. This may imply that maintenance of P4 (even in the absence of a Luteotropic signal) during critical periods such as pregnancy recognition, is dependent on the proper luteinization and function of the large luteal cell.