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1
Clausmeyer, Jan, Alexander Botz, Denis Öhl, and Wolfgang Schuhmann. "The oxygen reduction reaction at the three-phase boundary: nanoelectrodes modified with Ag nanoclusters." Faraday Discussions 193 (2016): 241–50. http://dx.doi.org/10.1039/c6fd00101g.
Повний текст джерелаАнотація:
Silver nanoclusters are deposited on bifunctional Θ-shaped nanoelectrodes consisting of a carbon nanoelectrode combined with a hollow nanopipette. The Θ-nanoelectrodes are used as model systems to study interfacial mass transport in gas diffusion electrodes and in particular oxygen-depolarized cathodes (ODC) for the oxygen reduction reaction (ORR) in chlor-alkali electrolysers. By local delivery of O2 gas to the electroactive Ag nanoclusters through the adjacent nanopipette, enhanced currents for the ORR at the Ag nanoparticles are recorded which are not accountable when considering the low solubility and slow diffusion of O2 in highly alkaline media. Instead, local oversaturation of O2 leads to current enhancement at the Ag nanoclusters. Due to the intrinsic high mass transport rates at the nanometric electrodes accompanied by local delivery of reactants, the method generally allows to study electrochemical reactions at single nanoparticles beyond the limitations induced by slow diffusion and low reactant concentration. Kinetic and mechanistic information, for instance derived from Tafel slopes, can be obtained from kinetic regimes not accessible to standard techniques.
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Shafiq, Kanza, Asif Mahmood, Mounir M. Salem-Bekhit, Rai Muhammad Sarfraz, Alanood S. Algarni, Ehab I. Taha, Ahd A. Mansour, Sami Al Zahrani та Yacine Benguerba. "Development and Optimization of Tamarind Gum-β-Cyclodextrin-g-Poly(Methacrylate) pH-Responsive Hydrogels for Sustained Delivery of Acyclovir". Pharmaceuticals 15, № 12 (8 грудня 2022): 1527. http://dx.doi.org/10.3390/ph15121527.
Повний текст джерелаАнотація:
Acyclovir has a short half-life and offers poor bioavailability. Its daily dose is 200 mg five times a day. A tamarind gum and β-cyclodextrin-based pH-responsive hydrogel network for sustained delivery of acyclovir was developed using the free-radical polymerization technique. Developed networks were characterized by FTIR, DSC, TGA, PXRD, EDX, and SEM. The effect of varying feed ratios of polymers, monomers, and crosslinker on the gel fraction, swelling, and release was also investigated. FTIR findings confirmed the compatibility of the ingredients in a new complex polymer. The thermal stability of acyclovir was increased within the newly synthesized polymer. SEM photomicrographs confirmed the porous texture of hydrogels. The gel fraction was improved (from 90.12% to 98.12%) with increased reactant concentrations. The pH of the dissolution medium and the reactant contents affected swelling dynamics and acyclovir release from the developed carrier system. Based on the R2 value, the best-fit model was zero-order kinetics with non-Fickian diffusion as a release mechanism. The biocompatibility of the developed network was confirmed through hematology, LFT, RFT, lipid profile, and histopathological examinations. No sign of pathology, necrosis, or abrasion was observed. Thus, a pH-responsive and biocompatible polymeric system was developed for sustained delivery of acyclovir to reduce the dosing frequency and improve patient compliance.
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Jahedbozorgan, Tayebeh, Minoo Yaghmaei, and Maryam Naserieh. "Comparison of serum ferritin levels in pregnant women with preterm and term deliveries." Immunopathologia Persa 6, no. 2 (May 9, 2020): e25-e25. http://dx.doi.org/10.34172/ipp.2020.25.
Повний текст джерелаАнотація:
Introduction: Despite high rates of mortality and morbidity due to preterm delivery, none of the diagnostic and biochemical tests could help to accurately identify the cases at risk of preterm delivery. Objectives: Since ferritin is an acute phase reactant, this study aimed to evaluate serum ferritin levels in women with preterm and term delivery. Methods: This study was conducted on 150 women with preterm delivery (50 cases in each of the groups 24-30, 30-34, and 34-37 weeks of pregnancy), 150 women with term delivery, and 150 pregnant women who were between 24-37 weeks of pregnancy (same as preterm delivery groups). Results: The mean ferritin level in all preterm groups was significantly higher than that in the term group, but there was no difference among the preterm groups. In addition, ferritin level in each preterm group was significantly higher than those in the normal pregnancy group at the same gestational age. In preterm deliveries, ferritin levels were significantly higher in cases with prelabor rupture of membranes (PROM) or with a prolonged leakage (longer than 12 hours). In addition, in patients with PROM or prolonged leakage, ferritin levels were significantly higher in preterm deliveries than in term deliveries. A ferritin level of 37.5 ng/mL recognized as the best cut-off for preterm delivery, as compared with term delivery, and its sensitivity, specificity, and diagnostic accuracy was 78.7%, 68.7%, and 73.6%, respectively. Conclusion: The findings of the present study showed that serum ferritin level can be used to find patients at risk of preterm delivery.
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Chadwick, Eric Alexander, Pranay Shrestha, Harsharaj Birendrasingh Parmar, Aimy Bazylak, and Volker Schulz. "Biomimetic Microchannels for the Passive Management of Water in PEM Fuel Cells." ECS Meeting Abstracts MA2022-02, no. 40 (October 9, 2022): 1455. http://dx.doi.org/10.1149/ma2022-02401455mtgabs.
Повний текст джерелаАнотація:
In polymer electrolyte membrane (PEM) fuel cells, the bipolar plates (BPPs) are responsible for the transport of reactants (via embedded flow fields), heat, and electrons, and account for 18-28% of the cost of fuel cell systems1. Thus, there is a great opportunity to improve the energy density of PEM fuel cells by improving the functions of BPPs, such as providing liquid water management, which affects reactant delivery and heat distribution. Previous work has shown that mass transport losses due to liquid water accumulation under the lands and channels of PEM fuel cell flow fields limit the power density of fuel cells2. Previous work has demonstrated that water will preferentially flow in a desired direction by implementing biomimetic wicking structures3; however, such wicking structures have not been previously implemented into a fuel cell. Furthermore, the design of BPPs has not been tailored to target areas of water accumulation. In this work, biomimetic geometries that promote passive unidirectional water wicking were implemented in a PEM fuel cell flow field to enhance liquid water removal and the distribution of reactant gases. The BPPs were characterized via constant current electrochemical testing and electrochemical impendence spectroscopy (EIS) to elucidate the dominant losses observed during operation. Operando synchrotron X-ray radiography was performed during the electrochemical testing in order to quantify the liquid water accumulation on the cathode side of the PEM fuel cell. The spatial distribution of liquid water was combined with EIS characterizations to explain the performance of the designs at high current densities, where mass transport losses typically dominate. The results from this work can be used to further optimize the design of PEM fuel cell bipolar plates in order to produce more efficient fuel cell stacks and drive PEM fuel cells into the global energy market. References Y. Wang, D. F. Ruiz Diaz, K. S. Chen, Z. Wang, and X. C. Adroher, Materials Today, 32, 178–203 (2020). N. Ge et al., Electrochimica Acta, 328, 135001 (2019). J. Feng and J. P. Rothstein, Journal of Colloid and Interface Science, 404, 169–178 (2013).
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GUO, LIN, WENCE DING, and FANDIAN MENG. "FABRICATION AND IN VITRO EVALUATION OF FOLATE-MODIFIED IRON FERRITE NANOPARTICLES WITH HIGH DOXORUBICIN LOADING FOR RECEPTORS-MAGNETIC-GUIDED DRUG DELIVERY." Nano 09, no. 02 (February 2014): 1450021. http://dx.doi.org/10.1142/s1793292014500210.
Повний текст джерелаАнотація:
Folate-modified iron ferrite nanoparticles with high doxorubicin loading (FDMP) were developed for dual targeting of tumor cells. Large quantities of doxorubicin and folate ligand were chemically coupled to the synthesized dual-functional magnetic nanoparticles by using the multihand cross-linker poly-L-glutamic acid. FDMP exhibits high drug loading ability, narrow size distribution and pH sensitivity to drug release. The drug loading ratio and the magnetic response can be adjusted by controlling the reactant ratio. FDMP possesses high magnetic-guided ability and exhibits enhanced uptake by folate receptors expressing tumor cells and increased cancer cell cytotoxicity.
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Lewinski, Krzysztof A., and Andrzej P. Jaworski. "Analysis of Flow Errors and Resulting Stoichiometry Uncertainties while Using a Fuel Cell Stack Test Station for Reactant Delivery and Control." ECS Transactions 5, no. 1 (December 19, 2019): 241–52. http://dx.doi.org/10.1149/1.2729006.
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Tanaka, Hiroki, Tatsunari Takahashi, Manami Konishi, Nae Takata, Masaki Gomi, Daiki Shirane, Ryo Miyama, et al. "Self‐Degradable Lipid‐Like Materials Based on “Hydrolysis accelerated by the intra‐Particle Enrichment of Reactant (HyPER)” for Messenger RNA Delivery." Advanced Functional Materials 30, no. 34 (June 23, 2020): 1910575. http://dx.doi.org/10.1002/adfm.201910575.
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Zhang, Qiang, Yohanes Pramudya, Wolfgang Wenzel, and Christof Wöll. "Modeling the Layer-by-Layer Growth of HKUST-1 Metal-Organic Framework Thin Films." Nanomaterials 11, no. 7 (June 22, 2021): 1631. http://dx.doi.org/10.3390/nano11071631.
Повний текст джерелаАнотація:
Metal organic frameworks have emerged as an important new class of materials with many applications, such as sensing, gas separation, drug delivery. In many cases, their performance is limited by structural defects, including vacancies and domain boundaries. In the case of MOF thin films, surface roughness can also have a pronounced influence on MOF-based device properties. Presently, there is little systematic knowledge about optimal growth conditions with regard to optimal morphologies for specific applications. In this work, we simulate the layer-by-layer (LbL) growth of the HKUST-1 MOF as a function of temperature and reactant concentration using a coarse-grained model that permits detailed insights into the growth mechanism. This model helps to understand the morphological features of HKUST-1 grown under different conditions and can be used to predict and optimize the temperature for the purpose of controlling the crystal quality and yield. It was found that reactant concentration affects the mass deposition rate, while its effect on the crystallinity of the generated HKUST-1 film is less pronounced. In addition, the effect of temperature on the surface roughness of the film can be divided into three regimes. Temperatures in the range from 10 to 129 °C allow better control of surface roughness and film thickness, while film growth in the range of 129 to 182 °C is characterized by a lower mass deposition rate per cycle and rougher surfaces. Finally, for T larger than 182 °C, the film grows slower, but in a smooth fashion. Furthermore, the potential effect of temperature on the crystallinity of LbL-grown HKUST-1 was quantified. To obtain high crystallinity, the operating temperature should preferably not exceed 57 °C, with an optimum around 28 °C, which agrees with experimental observations.
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Chen, Xiaolong, Yutong Zheng, Yuzhi Jiang, Yaxiong Ji, Shifeng Wang, and Fujia Yu. "Simple and Rapid High-Yield Synthesis of Sub-100 nm Nano-SiO2·0.5H2O Particles Based on Wollastonite." Coatings 9, no. 10 (October 13, 2019): 662. http://dx.doi.org/10.3390/coatings9100662.
Повний текст джерелаАнотація:
Amorphous nano-SiO2·nH2O particles has drawn much attention in industrial applications because of the features of high purification, low density, large specific surface area, fine decentralization, good optical, and mechanical performances. However, the applications have been hindered by the exorbitant price and the serious agglomeration. In this work, using wollastonite as reactant, H2SO4 as solvent, and adding sodium dodecyl benzene sulfonate (SDBS) as surfactant, sub-100 nm amorphous nano-SiO2·0.5H2O particles with good dispersibility, controllable agglomeration, narrow size distribution, and high yield were prepared by a low-cost and simple chemical method. The prepared sphere-like amorphous nano-SiO2·0.5H2O particles with average diameter of 70 nm were absorbed by the SDBS on the surface. The reaction conditions were systematically studied and the optimal technologic condition of the preparation was also confirmed. The achievement had a great perspective for the industrialization of high-quality nano-SiO2·nH2O particles, which hold great promise for various applications, such as plasmonic and catalytic nanoparticles supporting, polymeric matrices strengthening, drug delivery, and adsorption processes.
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Sumera, Florentino C., Shienna Marie A. Pontillas, Josanelle Angela V. Bilo, and John Marty Mateo. "New Poly(Hydroxylauric-co-Lactic Acid) Liquid Polymer for Dissolving Lipophilic Drugs." KIMIKA 28, no. 1 (July 7, 2017): 20–25. http://dx.doi.org/10.26534/kimika.v28i1.20-25.
Повний текст джерелаАнотація:
A liquid, biocompatible polyester based polymer, which could facilitate injectable formulations by simple mixing with the active substance (drug) is much needed by the pharmaceutical companies. A favourite candidate is polylactic acid (PLA) which is biocompatible and biodegradable. However PLA is solid with high crystallinity. Thus, in this research, hydroxylauric acid (HOLA) was copolymerized with lactic acid (LA) in different ratios by polycondensation technique at 180 °C, without a metal catalyst and avoiding the formation of interfering lactides, to provide a liquid polyester. The copolymers molecular weights were determined by Gel Permeation Chromatography (GPC) and their physical states indicated as solid or liquid were noted. The structures as polyesters were confirmed by FT-IR and 1H NMR spectroscopy. Poly(HOLA:LA) products from reactant ratios 0:100 is solid, while ratios of 20:80, 40:60 are mixed (paste) and 60:40, 80:20 and 100:0 are liquids. Thus, the liquid polyesters from the polycondensation of HOLA and LA without catalyst were picked as potential candidates for dissolving hydrophobic drugs that could be used as injectables in controlled drug delivery experiments.
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Walsh, Sara, Jack Reynolds, Bahaa Abbas, Rachel Woods, Justin Searle, Eifion Jewell, and Jonathon Elvins. "Assessing the Dynamic Performance of Thermochemical Storage Materials." Energies 13, no. 9 (May 2, 2020): 2202. http://dx.doi.org/10.3390/en13092202.
Повний текст джерелаАнотація:
Thermochemical storage provides a volumetric and cost-efficient means of collecting energy from solar/waste heat in order to utilize it for space heating in another location. Equally important to the storage density, the dynamic thermal response dictates the power available which is critical to meet the varied demands of a practical space heating application. Using a laboratory scale reactor (127 cm3), an experimental study with salt in matrix (SIM) materials found that the reactor power response is primarily governed by the flow rate of moist air through the reactor and that creating salt with a higher salt fraction had minimal impact on the thermal response. The flowrate dictates the power profile of the reactor with an optimum value which balances moisture reactant delivery and reaction rate on the SIM. A mixed particle size produced the highest power (22 W) and peak thermal uplift (32 °C). A narrow particle range reduced the peak power and peak temperature as a result of lower packing densities of the SIM in the reactor. The scaled maximum power density which could be achieved is >150 kW/m3, but achieving this would require optimization of the solid–moist air interactions.
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Ozaki, Masataka. "Preparation and Properties of Well-Defined Magnetic Particles." MRS Bulletin 14, no. 12 (December 1989): 35–40. http://dx.doi.org/10.1557/s0883769400060942.
Повний текст джерелаАнотація:
Magnetic particles are important not only in the technology, but also in the function of some biosystems. In addition, they are of great scientific interest in developing a better understanding of magnetic phenomena. Ever since magnetic recording media were first prepared, extensive efforts have been made to produce improved magnetic dispersions. The particle s for magnetic media must be of single domain, high saturation magnetization, and proper coercive force. However, the magnetic interactions between such particles are very strong, and stable dispersions are difficult to obtain. Originally, their use was limited to audio tapes, but presently they are employed in a variety of applications. Thus, small particles of different magnetic properties are constituents of magnetic fluids.In 1975, magnetic particles were identified in the bodies of some bacteria, which can navigate along geomagnetic fields. It is also believed that certain animais have the ability to detect a magnetic field due to the presence of magnetic particles in their cells.Techniques are being developed to introduce new functions to materials by incorporating magnetic particles. For example, magnetic particles that are encapsulated by nonmagnetic compounds (e.g. polymers) or particles are used for binding and separating enzymes from reactant mixtures. Efforts are under way to use magnetic particles in drug delivery Systems and for diagnosis.
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Paul, Mobin, Priyanka C. G., Sophy M. P., Latha Abraham, Rajesh Venkitakrishnan, Renji Jos, and Jaicob Varghese. "Compassionate use of convalescent plasma for the management of severe pneumonia in critically ill COVID-19 patients-a single center experience, Kerala, India." International Journal of Research in Medical Sciences 9, no. 10 (September 28, 2021): 3156. http://dx.doi.org/10.18203/2320-6012.ijrms20213948.
Повний текст джерелаАнотація:
We assessed treatment effectiveness with convalescent plasma in critically ill COVID-19 pneumonia patients and their association with reduction in C reactive protein level as a sensitive inflammatory marker to the ongoing cytokine storm. Retrospective cohort study based on the detailed electronic medical chart review. The primary outcome was a clinical improvement on day 14, defined as the reduction in cytokine storm as demonstrated by a drop in acute phase reactant C reactive protein; de-escalation from the prior mode of oxygen delivery or not on mechanical ventilation in critically ill COVID-19 patients. C reactive protein was measured by using immunoturbidimetry. IgG antibody against spike protein S1 was measured by chemiluminescent immunoassay. Of 14 patients, all had severe COVID-19 pneumonia [category C], and 9 (64%) were mechanically ventilated soon after the admission into the medical intensive care unit. De-escalation of the oxygenation strategy mode was noted in 11 (79%) patients after convalescent plasma infusion. All patients showed a significant drop in C reactive protein when compared to pre-infusion and post-infusion day 5. Early compassionate use of convalescent plasma with higher titters of IgG antibodies against S1may positively benefit the overall outcome in critically ill COVID-19 patients with severe pneumonia.
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Gomersall, D. E., and A. J. Flewitt. "Plasma enhanced chemical vapor deposition of p-type Cu2O from metal organic precursors." Journal of Applied Physics 131, no. 21 (June 7, 2022): 215301. http://dx.doi.org/10.1063/5.0089757.
Повний текст джерелаАнотація:
The scope of this work was to optimize the reactant delivery parameters for the plasma enhanced chemical vapor deposition (PECVD) of p-type [Formula: see text] films from Cu(hfac)(tmvs), with the aim to explore an alternative to other large-area deposition techniques such as sputtering. While n-type metal oxide semiconductors such as amorphous indium gallium zinc oxide have now been developed and offer significantly improved device performance over hydrogenated amorphous silicon, with devices achieving mobilities [Formula: see text], there is still an absence of good p-type inorganic semiconductors that provide similar performance. [Formula: see text] is a promising p-type metal oxide, but there remain limitations on the industrial scalability of some of the deposition processes demonstrated so far. PECVD has been scaled for uniform deposition on generation 10 display glass ([Formula: see text]) and so provides a viable alternative. The [Formula: see text] films deposited in this work achieved a Hall mobility of [Formula: see text] and were stable over a period of months. Contrary to previous reports of an “incubation” period, the initial growth rate during and immediately following nucleation was ([Formula: see text]40 nm/pulse) 10 times greater than the steady state growth ([Formula: see text]4 nm/pulse) achieved later in the deposition. Topographical scaling methods and fractal analysis of the film surface morphology using atomic force microscopy, at different stages during growth development, link this shift to a regime transition from growth dominated by surface diffusion to volume diffusion.
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Manoharan, Yogesh, Seyed Ehsan Hosseini, Brayden Butler, Hisham Alzhahrani, Bhi Thi Fou Senior, Turaj Ashuri, and John Krohn. "Hydrogen Fuel Cell Vehicles; Current Status and Future Prospect." Applied Sciences 9, no. 11 (June 4, 2019): 2296. http://dx.doi.org/10.3390/app9112296.
Повний текст джерелаАнотація:
The hazardous effects of pollutants from conventional fuel vehicles have caused the scientific world to move towards environmentally friendly energy sources. Though we have various renewable energy sources, the perfect one to use as an energy source for vehicles is hydrogen. Like electricity, hydrogen is an energy carrier that has the ability to deliver incredible amounts of energy. Onboard hydrogen storage in vehicles is an important factor that should be considered when designing fuel cell vehicles. In this study, a recent development in hydrogen fuel cell engines is reviewed to scrutinize the feasibility of using hydrogen as a major fuel in transportation systems. A fuel cell is an electrochemical device that can produce electricity by allowing chemical gases and oxidants as reactants. With anodes and electrolytes, the fuel cell splits the cation and the anion in the reactant to produce electricity. Fuel cells use reactants, which are not harmful to the environment and produce water as a product of the chemical reaction. As hydrogen is one of the most efficient energy carriers, the fuel cell can produce direct current (DC) power to run the electric car. By integrating a hydrogen fuel cell with batteries and the control system with strategies, one can produce a sustainable hybrid car.
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Bukhoeri, Ahmad, Syarief Thaufik Hidayat, Ediwibowo Ambari, Julian Dewantiningrum, Putri Sekar Wiyati, and Besari Adi Pramono. "Differences of Ampicillin and Cefazolin Effects in Reducing hs-CRP Level in Premature Rupture of Membranes." Diponegoro International Medical Journal 2, no. 1 (March 10, 2021): 1–5. http://dx.doi.org/10.14710/dimj.v2i1.8428.
Повний текст джерелаАнотація:
Background: Premature rupture of membranes (PROM) is a rupture of amniotic sac before delivery. PROM is associated with an increased incidence of preterm labor and infection. The use of prophylactic antibiotic may reduce the risks of infection. High-sensitivity C-reactive protein (hs-CRP) is an acute-phase reactant protein that is associated with PROM. How much effect of prophylactic antibiotic to hs-CRP level remains unclear.Objective: To compare the reduction in hs-CRP levels in premature rupture of membranes before and after given ampicillin or cefazolin.Methods: The design of this study was true experimental design (pre and post-test) conducted at Dr. Kariadi General Hospital Medical Center Semarang and Kartini General Hospital Jepara from September 2019 to January 2020. Study samples are pregnant women with premature rupture of membranes that came to the Emergency Department and Maternity Ward Dr. Kariadi General Hospital Medical Center Semarang and Kartini General Hospital Jepara. Samples were divided into two groups, a group treated with ampicillin and the other with cefazolin therapy. All samples were subjected to a hs-CRP examination. Statistical analysis was performed by Mann-Whitney and Wilcoxon.Results: There are no significant differences in the age variable (28.8 ± 6.54 vs 29.1 ± 5.93), gestational age (36.3 ± 2.55 vs 36.3 ± 2.90), and parity (2,2 ± 0.99 vs 2.47 ± 1.19) in the ampicillin and cefazolin groups (p> 0.05). In this study, 37.1% patients have a history of PROM while 62.9%. had no history of PROM. Reduction in hs-CRP levels after administration of ampicillin and cefazolin was significant (4.4 ± 2.65 mg/L vs 6.3 ± 4.43 mg/L, respectively, p = 0.03). The difference in the decrease in hs-CRP levels before and after given ampicillin and cefazolin was significant (p = 0.0001). Conclusion: There is a decrease in hs-CRP levels after the administration of ampicillin or cefazolin in PROM, whereas cefazolin induced higher reduction in hs-CRP levels. Ampicillin can still be used as a first-line prophylactic antibiotic in primary healthcare facilities.
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Ullah, Kaleem, Shujaat Ali Khan, Muhammad Sohail, Abdul Mannan, and Ghulam Murtaza. "Pharmacokinetic Profile of Oxaliplatin-Loaded pH-Responsive Hydrogels in Rabbits." Current Pharmaceutical Design 26, no. 44 (December 22, 2020): 5755–63. http://dx.doi.org/10.2174/1381612826666200813125159.
Повний текст джерелаАнотація:
Background: Oxaliplatin (OXP), a 3rd generation platinum compound, which causes severe side effects due to; impulse high concentration in the bloodstream thereby exposing healthy cells at a high ratio, nonspecific delivery at the target site and non-compliance is administered intravenously. Objective: The project was aimed at the development, characterization, and in-vitro and in-vivo evaluation of pHresponsive hydrogels for oral administration of OXP. Methods: Hydrogel formulations were synthesized through a free radical polymerization technique followed by brief characterization using various techniques. The hydrogels were investigated for various in-vitro studies such as sol-gel, drug loading, swelling, drug release, and MTT-assay. While in-vivo studies such as oral tolerability, histopathology, and hematology studies were performed on rabbits. A simple and sensitive HPLC-UV method was optimized and the comparative pharmacokinetic study was performed in rabbits using OXP-oral solution and OXP-loaded hydrogels. Results: In-vitro characterization confirmed that the reactant was successfully crosslinked to form thermally stable hydrogels with decreased crystallinity and rough surface. Swelling and drug release showed that hydrogels were more responsive to basic pH (6.8 and 7.4) in comparison with pH 1.2. The blank hydrogels were cytocompatible as more than 95% of the cells were viable while free OXP and OXP-loaded hydrogels displayed dosedependent cytotoxic effect. In-vivo studies confirmed that chitosan and gelatin hydrogel suspension was well tolerable up to 3800 mg/kg and 4000 mg/kg of body weight, respectively. Hematology and serum chemistry reports were well within the range suggesting normal liver and kidney functions. Similarly, histopathology slides of rabbit vital organs were also found normal without causing any histopathological change. Conclusion: HPLC-UV method was successfully optimized for OXP detection in oral solution and hydrogels administered to rabbits. A significant difference was found among various pharmacokinetic parameters by comparing the two groups including half-life (t1/2), tmax, Cmax, AUCtot MRT, Vz, and Lz.
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Yadav, Ramesh, and Hemsagar Rimal. "Changes in Level of C-reactive Protein at 0 hours and at 72 hours among Neonates with Suspected Sepsis at Neonatal Intensive Care Unit of Birat Medical College Teaching Hospital." Birat Journal of Health Sciences 6, no. 3 (December 31, 2021): 1636–41. http://dx.doi.org/10.3126/bjhs.v6i3.43213.
Повний текст джерелаАнотація:
Introduction: Neonatal sepsis still remains serious and potentially life-threatening events with a mortality rate of up to 50% in very premature infants. Efforts were made to improve laboratory sepsis diagnosis. C-reactive protein (CRP) is the most extensively studied acute phase reactant so far. Very few studies have been done to see the variation of serial measurement of CRP titer. Objectives: To find out the level of CRP titer at 0 hour and at 72 hours among neonates with suspected sepsis at the neonatal intensive care unit of Birat Medical College Teaching Hospital. Methodology: It was a cross-sectional descriptive study from 26 March 2021 to 25 July 2021, to see serial CRP titre among the sepsis suspected neonates at the Neonatal intensive care unit of Birat Medical College Teaching Hospital. A Total of 95 cases of neonates suspected sepsis were enrolled and their serial CRP titre at o0 hour and 72 hours were studied. The data was entered into Microsoft office excel and analyzed using statistical package for social sciences (SPSS 20.0) Results: There was no significant association of gender, birth weight, mode of delivery and gestational age with an increase of CRP at 0 to 72 hours after birth. Among the enrolled neonates 34 had positive blood culture while 61 had blood culture which was sterile. It showed that, 70.6% who had blood culture positive had increased CRP level at 0 to 72 hours whereas only 29.4% had not no increment in CRP despite positive blood culture. Conclusions: CRP titre increment at 72 hours after the first one correlated better with culture proven sepsis in comparison to CRP titer increment at 0 hours after birth. The sensitivity, specificity, positive and negative predictive values as calculated in this study are not high enough to make it a good screening test. The test is not specific enough to rely upon as the sole indicator. The clinical judgment along with other hematological parameters and diagnostic markers along with serial CRP should be considered in evaluating a neonate for sepsis.
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Ham, Chaeyoung Tina, Pranay Shrestha, Leya Roshani Kober, and Aimy Bazylak. "Visualizing 4D Pore-Scale Gas Transport in Operating PEM Electrolyzers Using X-Ray Computed Tomography." ECS Meeting Abstracts MA2022-02, no. 39 (October 9, 2022): 1418. http://dx.doi.org/10.1149/ma2022-02391418mtgabs.
Повний текст джерелаАнотація:
Mass transport losses in polymer electrolyte membrane (PEM) electrolyzers are predominantly caused by the accumulation of oxygen gas within the pores of the porous transport layer (PTL), hindering reactant water delivery to reaction sites (1). To enhance mass transport and optimize electrolyzer performance, a comprehensive understanding of the mechanisms driving oxygen gas transport in the PTL is required. Numerous studies have utilized various imaging techniques - including optical, neutron, and X-ray radiography to elucidate the evolution and transport of oxygen gas in the multiphase flow regime during PEM electrolyzer operation (2). However, these techniques only capture two-dimensional (2D) images, resolving average gas distributions rather than a holistic pore-scale quantification. Few studies have used three-dimensional (3D) imaging to resolve the dynamic microscale distributions of oxygen gas in the PTL. Understanding the impact of key parameters affecting 3D oxygen gas transport, such as PTL morphology, will allow for tailored pore-scale material optimization for enhanced gas transport and improved performance of PEM electrolyzers. This study presents a non-destructive operando imaging approach using X-ray computed tomography (CT), enabling the visualization of transient 3D oxygen gas evolution and transport in the PTL of a PEM electrolyzer. Using state-of-the-art synchrotron X-rays, high temporal and spatial resolutions were achieved to capture the pore-scale formation and growth of oxygen gas pathways within the PTL at various operating conditions. Electrochemical performance of an in-house designed electrolyzer cell was also characterized while acquiring tomographic images to investigate the impact of observed transport mechanisms on performance. The methodology presented in this work showcases the capability of using X-ray CT to visualize the complex interfacial multiphase flow in PTLs. Findings from this study will provide valuable insight towards pore-scale material optimization of clean energy porous materials aimed at curtailing the costs of green hydrogen production. References 1. M. Suermann, T. J. Schmidt, and F.N. Büchi, ECS Trans., 69(17), 1141-1148 (2015). 2. M. Maier, K. Smith, J. Dodwell, G. Hinds, P. R. Shearing, and D. J. L. Brett, Int. J. Hydrog. Energy., 47(1), 30-56 (2022).
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Sauer, Vinicius M., Fernando F. Fachini, and Derek Dunn-Rankin. "Non-premixed swirl-type tubular flames burning liquid fuels." Journal of Fluid Mechanics 846 (May 4, 2018): 210–39. http://dx.doi.org/10.1017/jfm.2018.248.
Повний текст джерелаАнотація:
Tubular flames represent a canonical combustion configuration that can simplify reacting flow analysis and also be employed in practical power generation systems. In this paper, a theoretical model for non-premixed tubular flames, with delivery of liquid fuel through porous walls into a swirling flow field, is presented. Perturbation theory is used to analyse this new tubular flame configuration, which is the non-premixed equivalent to a premixed swirl-type tubular burner – following the original classification of premixed tubular systems into swirl and counterflow types. The incompressible viscous flow field is modelled with an axisymmetric similarity solution. Axial decay of the initial swirl velocity and surface mass transfer from the porous walls are considered through the superposition of laminar swirling flow on a Berman flow with uniform mass injection in a straight pipe. The flame structure is obtained assuming infinitely fast conversion of reactants into products and unity Lewis numbers, allowing the application of the Shvab–Zel’dovich coupling function approach.
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Cetinkaya, Salih, Gulnur Ozaksit, Ebru Hacer Biberoglu, Asli Oskovi, and Ayse Kirbas. "The value of acute phase reactants in predicting preterm delivery." Journal of Maternal-Fetal & Neonatal Medicine 30, no. 24 (January 17, 2017): 3004–8. http://dx.doi.org/10.1080/14767058.2016.1271409.
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Sprocati, Riccardo, Andrea Gallo, Rajandrea Sethi, and Massimo Rolle. "Electrokinetic Delivery of Reactants: Pore Water Chemistry Controls Transport, Mixing, and Degradation." Environmental Science & Technology 55, no. 1 (December 9, 2020): 719–29. http://dx.doi.org/10.1021/acs.est.0c06054.
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Li, Peng, Yun Chen, Chu Liang, Chengfu Zeng, Xiaoyu (Baohua) Zhang, Haichang Zhong, Wenxian Zhang, Xiaohua Zheng, and Mingxia Gao. "CO2 Pressure-Dependent Microstructure and Morphology of Carbon for Energy Storage: Unraveling the Role of CO2 in Green Synthesis of Carbon Materials." Batteries 9, no. 2 (February 12, 2023): 130. http://dx.doi.org/10.3390/batteries9020130.
Повний текст джерелаАнотація:
Advanced carbon materials have played an important function in the field of energy conversion and storage. The green and low-carbon synthesis of elemental carbon with controllable morphology and microstructure is the main problem for carbon materials. Herein, we develop a green and low-carbon method to synthesize porous carbon by reacting CO2 with LiAlH4 at low temperatures. The starting reaction temperatures are as low as 142, 121, and 104 °C for LiAlH4 reacting with 1, 30, and 60 bar CO2, respectively. For the elemental carbon, the porosity of elemental carbon gradually decreased, whereas its graphitization degree increased as the CO2 pressure increased from 1 bar to 60 bar. CO2 serves as one of the two reactants and the CO2 pressure can adjust the thermodynamic and kinetic properties of the formation reaction for synthesizing elemental carbon. The mechanism for CO2 pressure-dependent microstructure and morphology of carbon is discussed on the basis of the formation reaction of elemental carbon and gas blowing effect of H2 and CO2. The elemental carbon with different morphology and microstructure exhibits distinct electrochemical lithium storage performance including reversible capacity, rate capability, cycling stability, and Coulombic efficiency, owing to their different lithium storage mechanism. The elemental carbon synthesized at 30 bar CO2 delivers the highest reversible capacity of 506 mAh g−1 after 1000 cycles even at 1.0 A g−1. Advanced energy storage technology based on the green and low-carbon synthesis of carbon materials is a requisite for providing a stable and sustainable energy supply to meet the ever-growing demand for energy.
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Wajdi Ibrahim, Wasan, and Maha Talib Mosa. "The Role of Acute Phase Reactants (Fibrinogen, Ferritin, Albumin, Calcium) in Pregnant Women with Preterm Delivery." Journal of the Faculty of Medicine Baghdad 64, no. 3 (October 17, 2022): 133–38. http://dx.doi.org/10.32007/jfacmedbagdad.6431943.
Повний текст джерелаАнотація:
Background: Preterm labor and related prematurity are predisposing factors that increase perinatal morbidity and mortality. Acute phase reactants are inflammatory markers which are positive and negative reactants explained by the reaction of reactants to the subclinical infection that are commonly associated with preterm labor. Objectives: To assess the role of acute phase reactants in pregnant women with preterm delivery. Patients and method: A case control study conducted in Gynecological Department of Baghdad Teaching Hospital from 1st February 2021 to 30th October 2021, on one hundred pregnant women with gestational age (28weeks - 36weeks+6days) who attended outpatient clinic; fifty pregnant women with established preterm labor as case group and fifty pregnant women with no signs and symptoms of preterm labor as control group. Data was collected using structured questionnaire included demographic features, and biochemical parameters (serum ferritin (ng/ml), albumin (gm/dl), fibrinogen (mg/dl), and calcium (mg/dl) . Results: Mean±SD serum ferritin in control group was (46.2 ± 16.2 ng/ml) while in case group (52.47 ± 11.6ng/ml) with significant difference between both groups (P=0.03), mean±SD serum albumin in control group (3.18 ± 0.31 ng/ml) while in case group (2.92 ± 0.39) with highly significant difference between both groups (P<0.001). Validity test of serum ferritin at cutoff ≥ 52.7 (ng/ml) in case group was as follows: Sensitivity (94%), specificity (90%), negative predictive value (94%), positive predictive value (90%) and the accuracy was (92%). The validity test of serum albumin at cutoff ≤ 3.06 (gm/dl) to detect the preterm labor as follows: Sensitivity (78%), specificity (86%), negative predictive value (78%), positive predictive value (83%) and the accuracy was (84%). Mean±SD serum fibrinogen in control group was (400.9 ± 38.1) while in case group was (410.7 ± 51.2) with no significant difference between both groups (P=0.1). Mean±SD serum calcium in control group was (8.1 ± 0.7) while in case group was (7.92 ± 0.5) with no significant difference between both groups (P=0.1). Conclusion: serum ferritin and albumin can be used in prediction of preterm labor in 3rd trimester.
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Bavireddi, Harikrishna, Raghavendra Vasudeva Murthy, Madhuri Gade, Sivakoti Sangabathuni, and Raghavendra Kikkeri. "Supramolecular metalloglycodendrimers selectively modulate lectin binding and delivery of Ru(ii) complexes into mammalian cells." Organic & Biomolecular Chemistry 14, no. 46 (2016): 10816–21. http://dx.doi.org/10.1039/c6ob01546h.
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Ashames, Akram, Kaleem Ullah, Moawia Al-Tabakha, Shujaat Ali Khan, Nageeb Hassan, Abdul Mannan, Muhammad Ikram, Manal Buabeid, and Ghulam Murtaza. "Development, characterization and In-vitro evaluation of guar gum based new polymeric matrices for controlled delivery using metformin HCl as model drug." PLOS ONE 17, no. 7 (July 28, 2022): e0271623. http://dx.doi.org/10.1371/journal.pone.0271623.
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Currently, hydrogels are considered as ideal biomaterials due to their unique structure and characteristics that facilitates considerable hydrophilicity, swelling, drug loading and release. In this study, we report pH-responsive GG-MAA-AMPS hydrogel delivery system prepared via free radical polymerization technique. Hydrogels were loaded with Metformin HCl as a model drug. Hydrogels were characterized through Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). FTIR confirmed the successful crosslinking of reactants, hydrogel network formation and drug loading. TGA and DSC proved the higher thermal stability of reactants after crosslinking and drug loading. XRD analysis showed decrease in crystallinity of drug after loading into the hydrogels. SEM revealed smooth and glassy appearance of both loaded and unloaded hydrogels. Gel content was increased with increase in concentration of reactants. Drug entrapment was decreased by increasing concentration of GG and AMPS while MAA acted inversely. Hydrogels displayed pH-dependent swelling and drug release behavior being high at pH 6.8 and 7.4 while low at acidic pH (1.2). Oral tolerability in rabbits showed that hydrogels were safe without causing any hematological or histopathological changes in healthy rabbits. Based on the obtained results, GG-MAA-AMPS can be considered as potential carrier for metformin HCl as well as other hydrophilic drugs.
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Muzart, Jacques. "A Journey from June 2018 to October 2021 with N,N-Dimethylformamide and N,N-Dimethylacetamide as Reactants." Molecules 26, no. 21 (October 21, 2021): 6374. http://dx.doi.org/10.3390/molecules26216374.
Повний текст джерелаАнотація:
A rich array of reactions occur using N,N-dimethylformamide (DMF) or N,N-dimethylacetamide (DMAc) as reactants, these two amides being able to deliver their own H, C, N, and O atoms for the synthesis of a variety of compounds. This account highlights the literature published since June 2018, completing previous reviews by the author.
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Zhang, Ming-Jian, Yandong Duan, Chong Yin, Maofan Li, Hui Zhong, Eric Dooryhee, Kang Xu, Feng Pan, Feng Wang, and Jianming Bai. "Ultrafast solid-liquid intercalation enabled by targeted microwave energy delivery." Science Advances 6, no. 51 (December 2020): eabd9472. http://dx.doi.org/10.1126/sciadv.abd9472.
Повний текст джерелаАнотація:
In chemical reactions, the breaking and formation of chemical bonds usually need external energy to overcome the activation barriers. Conventional energy delivery transfers energy from heating sources via various media, hence losing efficiency and inducing side reactions. In contrast, microwave (MW) heating is known to be highly energy efficient through dipole interaction with polar media, but how exactly it transmits energy to initiate chemical reactions has been unknown. Here, we report a rigorous determination of energy delivery mechanisms underlying MW-enabled rapid hydrothermal synthesis, by monitoring the structure and temperature of all the involved components as solid-liquid intercalation reaction occurs using in situ synchrotron techniques. We reveal a hitherto unknown direct energy transmission between MW irradiation source and the targeted reactants, leading to greatly reduced energy waste, and so the ultrafast kinetics at low temperature. These findings open up new horizons for designing material synthesis reactions of high efficiency and precision.
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CHAO, VICTOR WEI-KEH (WU). "STEREODYNAMICS, MASS EFFECT AND DOCKING FROM O(3P) + HD → OH + D AT Ecol = 0.4–1.0eV AND O(3P) + HD → OD + H AT Ecol = 0.5–1.0eV." Journal of Theoretical and Computational Chemistry 12, no. 01 (February 2013): 1250104. http://dx.doi.org/10.1142/s0219633612501040.
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Quasiclassical Trajectory (QCT) calculation for O(3P) + HD → OH + D and O(3P) + HD → OD + H at E col = 0.4–1.0 eV and 0.5–1.0 eV, respectively, on the lowest PES 1 3A″ of Kuppermann et al. has been done. Distribution p(ϑr) of azimuthal angles between the relative velocity k of the reactants and rotational angular momentum vector j′ of either OH or OD , p(φr) of polar as well as dihedral angles correlating k - k′ -j′, p(ϑr, φr), and PDDCS dependent upon the scattering angle ϑt of either OH , or OD between k and k′ of the reactants and products, respectively, are presented and discussed. The stereodynamics and isotopic mass effects at the smallest possible collision energies 0.4 eV and 0.5 eV for OH and OD , respectively, are significantly different. The significant mass effect with quotient 1/2 of H/D, at the corresponding collision threshold may be applied for the investigation of docking mechanism, drug modification and delivery.
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Bracher, Paul J., Malancha Gupta, and George M. Whitesides. "Patterned paper as a template for the delivery of reactants in the fabrication of planar materials." Soft Matter 6, no. 18 (2010): 4303. http://dx.doi.org/10.1039/c0sm00031k.
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Krishna, Vijay, Alan Chen, and Prajakatta Mulay. "Engineered Carbon Nanostructures for Preventing Alzheimer’s Disease." ECS Meeting Abstracts MA2022-01, no. 8 (July 7, 2022): 703. http://dx.doi.org/10.1149/ma2022-018703mtgabs.
Повний текст джерелаАнотація:
Alzheimer’s disease (AD) is an aging-associated devastating disease that affects over 5 million Americans and imposes an annual economic burden of $236 billion. Currently, all efforts to develop remedies to AD have failed. This unfortunate situation calls for the development of new research directions. One of the common pathological features of AD is the decline in endogenous production of hydrogen sulfide (H2S), a gaseous signaling molecule. H2S in the brain is historically believed to be solely derived via enzymatic production and deficiencies in H2S producing enzymes, such as cystathionine-γ-lyase (CGL) and cystathionine-β-synthase (CBS) are associated with neurodegenerative diseases. Exogenous administration of H2S and H2S donors have shown to attenuate Alzheimer’s and Parkinson’s disease phenotypes in rodent models. However, exogenous H2S gas and donor molecules are short-lived, highly reactive, and display acute toxicity at elevated levels, and delivery to the intended tissue may be challenging to achieve in the clinic. Thus, discovering new technologies that regulate and/or augment endogenous enzymatic H2S pose novel scientific and therapeutic avenues particularly for the treatment of neurodegenerative disorders such as Alzheimer’s disease. We are designing enzyme-mimicking carbon nanostructures (EMCNs) that can augment the production of H2S using biological substrates present in the body and compensate for the declining enzyme activity and prevent the progression of Alzheimer’s disease. Carbon nanostructures with sp2 carbons are composed of multiple electron-deficient double bonds, which can be systematically replaced with functional groups to create a heterogeneous surface that is fundamentally different from that originally present. Based on the sp2 site engineering concept, we selected and synthesized EMCNs capable of interacting with the sulfur-containing biomolecules, catalyzing their breakdown into H2S and other products, thus mimicking CGL and CBS enzymes. The ability of EMCNs to mimic enzymes was evaluated with lead acetate saturated paper-based assay. EMCNs break down cysteine to produce H2S, which reacts with lead acetate to form lead sulfide. The concentration of H2S generated is calculated by using sodium hydrosulfide as an equimolar H2S donor for calibration. The H2S generation from EMCNs can be matched with the CBS enzyme. Further, EMCNs are stable and demonstrate long-term activity. In a repeated exposure experiment, H2S production was constant over a 20 day period where the substrate was added every day without replenishing ECMNs. If EMCNs were a reactant, the H2S production should have decreased with repeated substrate addition until all the EMCN was consumed. The efficacy of EMCNs to produce H2S in vitro was demonstrated with murine neuronal cells. P3 multi-photon fluorescent probe was utilized to detect intracellular H2S levels. The fluorescence intensity of the neuronal cells exposed to EMCN increased in a concentration-dependent manner. Neither cells nor EMCN exhibited auto-fluorescence under multi-photon microscopy. Beta-amyloid (Aβ) plaques, a hallmark of brain pathology in Alzheimer's disease patients, is formed by aggregation of β-amyloid peptides. The role of EMCNs in the AD model was evaluated with β-amyloid toxicity assay using Aβ1-42, which is selectively toxic to neurons. Preliminary studies suggest that EMCNs protect neuronal cells against the toxicity induced by Aβ1-42 by 19%. The ability of EMCNs to produce H2S under physiological conditions thus offers potential for rescuing enzyme deficiencies in Alzheimer’s disease.
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Lo, Yu-Lun, Hung-Wei Wang, Zi-Xian Liao, and Li-Fang Wang. "The synthesis and comparison of chondroitin sulfate-modified PDMAEMA with chondroitin sulfate-modified PEI as a potential gene delivery vector." RSC Advances 6, no. 44 (2016): 38209–22. http://dx.doi.org/10.1039/c6ra01957a.
Повний текст джерелаАнотація:
CS-PDMAEMA obtained by reacting HS-PDMAEMA with CSMA via Michael addition, shows lower cytotoxicity and better transfection efficiency than PDMAEMA. The transfection efficiency is higher in 3T3 cells than in U87 cells owing to higher expression of ASGP-R.
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Godefroy, S., M. Peyre, N. Garcia, S. Muller, D. Sesardic, and C. D. Partidos. "Effect of Skin Barrier Disruption on Immune Responses to Topically Applied Cross-Reacting Material, CRM197, of Diphtheria Toxin." Infection and Immunity 73, no. 8 (August 2005): 4803–9. http://dx.doi.org/10.1128/iai.73.8.4803-4809.2005.
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ABSTRACT The high accessibility of the skin and the presence of immunocompetent cells in the epidermis makes this surface an attractive route for needle-free administration of vaccines. However, the lining of the skin by the stratum corneum is a major obstacle to vaccine delivery. In this study we examined the effect of skin barrier disruption on the immune responses to the cross-reacting material CRM197, a nontoxic mutant of diphtheria toxin (DTx) that is considered as a vaccine candidate. Application of CRM197, together with cholera toxin (CT), onto the tape-stripped skin of mice elicited antibody responses that had anti-DTx neutralizing activity. Vaccine delivery onto mildly ablated skin or intact skin did not elicit any detectable anti-CRM197 antibodies. Mice immunized with CRM197 alone onto the tape-stripped skin mounted a vigorous antigen-specific proliferative response. In contrast, the induction of cellular immunity after CRM197 deposition onto mildly ablated or intact skin was adjuvant dependent. Furthermore, epidermal cells were activated and underwent apoptosis that was more pronounced when the stratum corneum was removed by tape stripping. Overall, these findings highlight the potential for transcutaneous delivery of CRM197 and establish a correlation between the degree of barrier disruption and levels of antigen-specific immune responses. Moreover, these results provide the first evidence that the development of a transcutaneous immunization strategy for diphtheria, based on simple and practical methods to disrupt the skin barrier, is feasible.
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Chang, Bei-jiann, Christopher P. Garcia, Donald W. Johnson, David J. Bents, Vincent J. Scullin, and Ian J. Jakupca. "Continous Operation of Polymer Electrolyte Membrane Regenerative Fuel Cell System for Energy Storage." Journal of Fuel Cell Science and Technology 4, no. 4 (May 3, 2006): 497–500. http://dx.doi.org/10.1115/1.2756848.
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NASA Glenn Research Center (GRC) has recently demonstrated a polymer electrolyte membrane (PEM) based regenerative fuel cell system (RFCS) that operated for five contiguous back-to-back 24h charge/discharge cycles over a period of 120h. The system operated continuously at full rated power with no significant reactant loss, breakdowns, or degradations from June 26 through July 1, 2005. It demonstrated a closed-loop solar energy storage system over repeated day/night cycles that absorbed solar electrical power profiles of 0–15kWe and stored the energy as pressurized hydrogen and oxygen gas in charge mode, then delivered steady 4.5–5kWe electrical power with product water during discharge mode. Fuel cell efficiency, electrolyzer efficiency, as well as system round-trip efficiency were determined. Individual cell performance and the spread of cell voltages within the electrochemical stacks were documented. The amount of waste heat dissipated from the RFCS was also reported. The RFCS demonstrated fully closed-cycle operation without venting or purging, thereby conserving reactant masses involved in the electrochemical processes. Smooth transitions between the fuel cell mode and electrolyzer mode were repeatedly accomplished. The RFCS is applicable to NASA’s lunar and planetary surface solar power needs, providing lightweight energy storage for any multikilowatt-electrical application, where an environmentally sealed system is required.
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Thambi, Thavasyappan, Jeongmin Lee, A.-Rum Yoon, Dayananda Kasala, and Chae-Ok Yun. "A pH- and Bioreducible Cationic Copolymer with Amino Acids and Piperazines for Adenovirus Delivery." Pharmaceutics 14, no. 3 (March 9, 2022): 597. http://dx.doi.org/10.3390/pharmaceutics14030597.
Повний текст джерелаАнотація:
Adenoviruses (Ads) are attractive nonviral vectors and show great potential in cancer gene therapy. However, inherent properties of Ads, including immunogenicity, nonspecific toxicity, and coxsackie and adenovirus receptor (CAR)-dependent cell uptake, limit their clinical use. To surmount these issues, we developed a pH- and glutathione-responsive poly(ethylene glycol)-poly(ꞵ-aminoester)-polyethyleneimine (PPA) for conjugation with Ad. The pH sensitivity of the PPA copolymer was elegantly tuned by substitution with different amino acids (arginine, histidine, and tryptophan), piperazines (Pip1, Pip2, and Pip3), and guanidine residues in the backbone of the PPA conjugate. PPA copolymer was further functionalized with short-chain cross-linker succinimidyl 3-(2-pyridyldithio)propionate) (SPDP) to obtain PPA-SPDP for facile conjugation with Ad. The PPA-conjugated Ad (PPA-Ad) conjugate was obtained by reacting PPA-SPDP conjugate with thiolated Ad (Ad-SH). Ad-SH was prepared by reacting Ad with 2-iminothiolane. The size distribution and zeta potential results of PPA-Ad conjugate showed an increasing trend with an increase in copolymer dose. From in vitro test, it was found that the transduction efficiency of PPA-Ad conjugate in CAR-positive cells (A549 and H460 cells) was remarkably increased at the acidic pH condition (pH 6.2) when compared with PPA-Ad conjugate incubated under the physiological condition (pH 7.4). Interestingly, the increase in transduction efficiency was evidenced in CAR-negative cells (MDA-MB-231 and T24 cells). These results demonstrated that biocompatible and biodegradable PPA copolymers can efficiently cover the surface of Ad and can increase the transduction efficiency, and hence PPA copolymers can be a useful nanomaterial for viral vector delivery in cancer therapy.
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Sahatsapan, Nitjawan, Theerasak Rojanarata, Tanasait Ngawhirunpat, Praneet Opanasopit, and Prasopchai Patrojanasophon. "Catechol-Functionalized Succinyl Chitosan for Novel Mucoadhesive Drug Delivery." Key Engineering Materials 819 (August 2019): 21–26. http://dx.doi.org/10.4028/www.scientific.net/kem.819.21.
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The objective of this research was to synthesized and evaluated a mucoadhesive catechol-bearing succinyl chitosan (Cat-SCS) as an innovative mucoadhesive substance for a mucoadhesive drug delivery system. Succinyl chitosan (SCS) was synthesized via ring-opening reactions with succinic anhydride. The Cat-SCS was then synthesized by reacting SCS with dopamine with the existence of N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDAC) and N-hydroxysulfosuccinimide (NHS). The successful functionalization of catechol onto chitosan backbone was verified using nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FT-IR). Mucoadhesion studies were performed using rheology measurement and ex-vivo mucoadhesion test. The findings exposed that the synthesized Cat-SCS exhibited excellent mucoadhesive properties which was better than the intact CS. Further indirect studies verified the occurrence of polymer-mucin glycoproteins interactions. The catechol content of catechol moiety on the Cat-SCS was determined to be 0.377 using the 1H NMR. The cytotoxicity test indicated the biocompatibility of the obtained polymer on human gingival fibroblast cells (HGF cells). Therefore, these results could advocate the capacity to use of Cat-SCS as an innovative mucoadhesive platform for mucoadhesive drug delivery.
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Xie, Jing, Lesheng Teng, Zhaogang Yang, Chenguang Zhou, Yang Liu, Bryant C. Yung, and Robert J. Lee. "A Polyethylenimine-Linoleic Acid Conjugate for Antisense Oligonucleotide Delivery." BioMed Research International 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/710502.
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A novel antisense oligonucleotide (ASO) carrier, polyethylenimine conjugated to linoleic acid (PEI-LA), was synthesized and evaluated for delivery of LOR-2501 to tumor cells. LOR-2501 is an ASO targeting ribonucleotide reductase R1 subunit (RRM1). In this study, PEI-LA was synthesized by reacting PEI (Mw ~ 800) with linoleoyl chloride. Gel retardation assay showed complete complexation between PEI-LA and LOR-2501 at N/P ratio above 8. No significant cytotoxicity was observed with these complexes at the tested dosage levels. Interestingly, at N/P ratio of >6, levels of cellular uptake of PEI-LA/LOR-2501 were double that of PEI/LOR-2501 complexes of the same N/P ratio. PEI-LA/LOR-2501 induced downregulation of 64% and 70% of RRM1 at mRNA and protein levels, respectively. The highest transfection activity was shown by PEI-LA/LOR-2501 complexes at N/P ratio of 10. Finally, using pathway specific inhibitors, clathrin-mediated endocytosis was shown to be the principle mechanism of cellular internalization of these complexes. In conclusion, PEI-LA is a promising agent for the delivery of ASOs and warrants further investigation.
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Saifuddin, Aiman Suhailah, Karmila Kamil, Halimatun Hashim, and Ruthraganapathy Radhakrishnan. "Capacitive and Inductive Line Reactance for Network Reconfiguration." Indonesian Journal of Electrical Engineering and Computer Science 8, no. 3 (December 1, 2017): 751. http://dx.doi.org/10.11591/ijeecs.v8.i3.pp751-755.
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<p>Solar PV may cause power congestion to occur in a transmission line when there is high solar irradiance that causing solar PV to generate more power flow than demanded power flow. Transmission line congestion that can be made worst by adding extra power generating farm such as centralized PV farm of renewable energy which helps to deliver customers with the demand or load required. The power generated coming from solar PV is depending on the weather and can definitely worsen the flow in transmission line due to the power captured. In this case, the high solar irradiance can affect the power generated from solar PV and will cause power congestion when power generated is higher than the load demanded. In this paper, the proposed method used to overcome the power congestion in a transmission line is by rerouting the excess power from the overloaded line to underloaded line by changing the line reactance of the line. An IEEE 30 bus test system is developed in PSS/E software as the test system. The output monitored is the line stability index of the affected line before and after rerouting process.</p>
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Miretti, Mariana, César German Prucca, Tomas Cristian Tempesti, and Maria Teresa Baumgartner. "Current Phthalocyanines Delivery Systems in Photodynamic Therapy: An Updated Review." Current Medicinal Chemistry 28, no. 26 (September 8, 2021): 5339–67. http://dx.doi.org/10.2174/0929867328666210208111234.
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Photodynamic therapy has emerged as an effective therapeutic alternative to treat oncological, cardiovascular, dermatological, infectious, and ophthalmic diseases. Photodynamic therapy combines the action of a photosensitizer with light in the presence of oxygen to generate reactive oxygen species, capable of reacting with cellular components, resulting in injury and, consequently, inducing cellular death. Phthalocyanines are considered good photosensitizers, although most of them are lipophilic, difficulting their administration for clinical use. A strategy to overcome the lack of solubility of phthalocyanines in aqueous media is to incorporate them into different delivery systems. The present review aimed to summarize the current status of the main drug delivery systems used for Zn and Al phthalocyanines and their effect in photodynamic therapy, reported in the last five years. Liposomes, polymeric micelles, polymeric nanoparticles, and goldnanoparticles constituted some of the most used carriers and were discussed in this review. The latest studies reported strongly suggest that the application of nanotechnologies as delivery systems allows an increase in photodynamic therapy efficacy and reduces side-effects associated with the phthalocyanine administration, which represents a hope for cancer treatments.
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Li, Min, Ru Xiao, Shaoqing Chen, Cheng Wang, and Xinye Ni. "Preparation and Optimization of Poly-Tannic Acid Nanoparticles as Potential Polymeric Drug or Drug Delivery Carrier." Journal of Biomaterials and Tissue Engineering 12, no. 12 (December 1, 2022): 2473–77. http://dx.doi.org/10.1166/jbt.2022.3203.
Повний текст джерелаАнотація:
Tannic acid (TA), as a common natural catechol derivative, has been widely applied as antibacterial drug or in the construction of carriers for drug delivery with metal ions. However, unlike dopamine, another catechol derivative whose polymerized form of nanoparticles have been successfully constructed and adopted in various biomedical fields, the development of poly-TA nanoparticles (PTANPs) is rarely reported and the optimization studies are even less. Therefore, the understanding of details and information regarding to the synthesis of PTANPs can provide insights into the polymerization process of TA and inspire the development of other catechol derivatives based nanoscale platforms for diverse scientific applications. Herein, we used a typical sodium hydroxide (NaOH) triggered polymerization followed by hydrogen peroxide (H2O2) degradation to prepare PTANPs. In our study, we explored the impact of temperature, weight/volume of reactants (TA, NaOH and H2O2) and reaction time (NaOH and H2O2) on the size of finally obtained PTANPs, which can give guidance and inspiration for future researches and facilitate the studies of followers.
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Maikov, I. L., and V. M. Zaichenko. "Analysis of the Process of Methane Pyrolysis in Polydisperse Porous Medium." Eurasian Chemico-Technological Journal 5, no. 1 (July 12, 2017): 39. http://dx.doi.org/10.18321/ectj588.
Повний текст джерелаАнотація:
The paper deals with the results of theoretical investigation of the process of methane pyrolysis an a polydisperse medium. A separate porous particle (macroparticle) is treated and this particle consists of different microparticles, which intersect randomly. A kinetic equation is used to describe the dynamics of a polydisperse system of microparticles in the process of methane pyrolysis. The reaction rate on the reaction surface of the particle is of the order of n with respect to the gas reactant. The reactant is delivered to the porous macroparticle via external diffusion layer outside of the particle and internal diffusion layer in the particle pores. A generalization of the expression for porosity for a polydisperse medium is made. Comparison is made of the times required for filling the pores for different initial size distributions of particles. A general analytical expression is derived describing the dependence of variation of the inner reaction surface on the degree of metamorphism of the porous skeleton for an arbitrary initial size distribution of particles. Comparison is made of the dependences of the degree of metamorphism of porous skeleton on dimensionless time for different initial distributions, namely, monodisperse, uniform, and normally<br />logarithmic with varying dispersion. It has been demonstrated that a polydisperse medium may be described by an effective structure parameter.
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van Scheers, Louise. "Managing the risk of outsourcing the IT function at companies." Risk Governance and Control: Financial Markets and Institutions 6, no. 3 (2016): 69–74. http://dx.doi.org/10.22495/rcgv6i3c2art9.
Повний текст джерелаАнотація:
The main objective for this secondary research is to determine whether the risk of outsourcing the IT function can be managed. Driven by political and economic dynamic changes, facilities management was borne to enable reacting to change. Doing business in today’s global economy requires exceptional skills from management in order to be competitive and to have a specific competitive advantage over competitors are getting even more demanding. One of the widest used methods of facilities management deployed by organisations is that of outsourcing in various forms (i.e. I.T., H.R., Distribution, Warehousing, etc.) for various different reasons (i.e. reduce costs, improve quality, focus on core business, etc.). In order for outsourcing to be successful, it needs to add benefits to profits, efficiency or effectiveness ethic. Outsourcing assists management to gain a competitive advantage over competitors within their specific industries as part of their organizational strategies and developing or strengthening core competencies at the same time. Global outsourcing on the other hand leads to controversy inasmuch as it reduces home-country economic activity and employment. The consulted secondary resources confirm that if outsourcing delivers managers can take calculated decisions to use it in their businesses. The future of outsourcing is promising as non-core functions of businesses may rather be outsourced to save on costs. A broad set of new and alternative IT delivery models are already main stream. These models receive attention because of benign economic market conditions.
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Al-Tabakha, Moawia M., Shujaat Ali Khan, Akram Ashames, Hamid Ullah, Kaleem Ullah, Ghulam Murtaza, and Nageeb Hassan. "Synthesis, Characterization and Safety Evaluation of Sericin-Based Hydrogels for Controlled Delivery of Acyclovir." Pharmaceuticals 14, no. 3 (March 8, 2021): 234. http://dx.doi.org/10.3390/ph14030234.
Повний текст джерелаАнотація:
Conventional formulations of antiviral drug acyclovir have various limitations such as low bioavailability. The current study was aimed at developing polymeric matrices for the controlled delivery of acyclovir using sericin as polymer and acrylic acid (AA) as a monomer. The free radical polymerization technique was used for hydrogel formulation. Briefly, sericin was chemically cross-linked with acrylic acid. N′-N′-methylene bis-acrylamide (MBA) and ammonium persulfate (APS) were used as cross-linker and initiator, respectively. FTIR spectra showed that acyclovir was successfully loaded into sericin hydrogel. SEM micrographs revealed that the outer surface was solid-like and smooth. According to DSC thermograms, the developed polymeric network was thermally stable. Amorphous nature of acyclovir was observed in XRD. The pH of medium and reactants’ concentration affected swelling dynamics and acyclovir release pattern. In addition, drug release occurred through a diffusion-controlled process. Sericin hydrogel suspension was well tolerable up to 3800 mg/kg of rabbits’ body weight. Haematology and serum chemistry results were well within the range signifying normal liver and kidney functions. Similarly, histopathology slides of the rabbit’s vital organs were also in normal condition without causing any histopathological change. It was concluded from the findings that sericin-co-AA polymeric matrices are ideal for the pH-dependent delivery of acyclovir.
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Ahner, Regine, Petra Kub-Csizi, Harald Heinzl, Diana Bikas, Michaela Rabl, Peter Wagenbichler, and Peter Husslein. "The fast-reacting fetal fibronectin test: A screening method for better prediction of the time of delivery." American Journal of Obstetrics and Gynecology 177, no. 6 (December 1997): 1478–82. http://dx.doi.org/10.1016/s0002-9378(97)70094-2.
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Fenin, Vikas, Vijay S. Kachawa, and Chandra P. Jain. "Optimization of Colon Specific Drug Delivery System for Ornidazole using Modified Gum." International Journal of Pharmaceutical Sciences and Drug Research 13, no. 02 (March 30, 2020): 176–82. http://dx.doi.org/10.25004/ijpsdr.2021.130210.
Повний текст джерелаАнотація:
The present study aimed to optimize a colon-specific formulation of ornidazole for the treatment of Crohn's disease and intestinal amoebiasis. Firstly carboxymethyl xanthan gum was prepared from xanthan gum reacting with monochloroacetic acid in alkaline conditions using the Williamson synthesis method. Fourier transform infrared spectrophotometer (FTIR) spectroscopy confirmed the formation of carboxymethyl xanthan gum. The differential scanning calorimetry (DSC) revealed the crystalline nature of carboxymethyl xanthan gum. A 32 full factorial design was used for optimization. The independent variables employed were the amount of Carboxymethyl Xanthan gum and the amount of hydroxy propyl methyl cellulose (HPMC), each at three levels. Drug release studies were carried out in various media [pH 1.2, 7.4, and 6.8]. The optimized formulation consisting of Carboxymethyl Xanthan gum (66 %) and HPMC (22%) released a small fraction of drug at pH 1.2 and pH 7.4, whereas significant drug release was observed at pH 6.8. The results of the study established Carboxymethyl Xanthan gum compression coated tablet to be a promising system for the colon-specific delivery of ornidazole to treat active Crohn's disease and intestinal amoebiasis.
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Kumar, Arun, Bimlesh Kumar, Sachin Kumar Singh, Barinder Kaur, and Saurabh Singh. "A REVIEW ON PHYTOSOMES: NOVEL APPROACH FOR HERBAL PHYTOCHEMICALS." Asian Journal of Pharmaceutical and Clinical Research 10, no. 10 (September 1, 2017): 41. http://dx.doi.org/10.22159/ajpcr.2017.v10i10.20424.
Повний текст джерелаАнотація:
The poor oral bioavailability of polyphenolic compound can be enhanced through the incorporation of them into phospholipid based self-assembled delivery system, i.e. popularly known as phytosome. “Phyto” means plants and “some” resembles a covering around/or a structure. Phytosome is generally prepared by reacting one or two moles of polyphenolic phytoconstituents and phospholipid. It may be either in the ratio of 1:1 and 1:2. By using phytosomes, one can also achieve enhanced rate and extent of the passage of lipophilic herbal constituents across lipid membrane that explains its character as a carrier as well as acid labile herbal drugs could also be protected in gastrointestinal tract. There are number of products available in the market that contains phytosomal drug delivery system such as Ginkgo biloba, Silybum marianum, and Camellia sinensis. The present review describes an updated overview of preparation of phytosomes, advancement in phytosomes technology, various herbal drugs for which phytosomes have been used as a carrier, its commercial availability and applications.
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Kalb, Jochen R., and Thomas Sattelmayer. "Lean Blowout Limit and NOx Production of a Premixed Sub-ppm NOx Burner With Periodic Recirculation of Combustion Products." Journal of Engineering for Gas Turbines and Power 128, no. 2 (March 1, 2004): 247–54. http://dx.doi.org/10.1115/1.2061267.
Повний текст джерелаАнотація:
The technological objective of this work is the development of a lean-premixed burner for natural gas. Sub-ppm NOx emissions can be accomplished by shifting the lean blowout limit (LBO) to slightly lower adiabatic flame temperatures than the LBO of current standard burners. This can be achieved with a novel burner concept utilizing spatially periodic recirculation of combustion products: Hot combustion products are admixed to the injected premixed fresh mixture with a mass flow rate of comparable magnitude, in order to achieve self-ignition. The subsequent combustion of the diluted mixture again delivers products. A fraction of these combustion products is then admixed to the next stream of fresh mixture. This process pattern is to be continued in a cyclically closed topology, in order to achieve stable combustion of, for example, natural gas in a temperature regime of very low NOx production. The principal ignition behavior and NOx production characteristics of one sequence of the periodic process was modeled by an idealized adiabatic system with instantaneous admixture of partially or completely burnt combustion products to one stream of fresh reactants. With the CHEMKIN-II package, a reactor network consisting of one perfectly stirred reactor (PSR, providing ignition in the first place) and two plug flow reactors (PFR) has been used. The effect of varying burnout and the influence of the fraction of admixed flue gas has been evaluated. The simulations have been conducted with the reaction mechanism of Miller and Bowman and the GRI-Mech 3.0 mechanism. The results show that the high radical content of partially combusted products leads to a massive decrease of the time required for the formation of the radical pool. As a consequence, self-ignition times of 1 ms are achieved even at adiabatic flame temperatures of 1600 K and less, if the flue gas content is about 50–60% of the reacting flow after mixing is complete. Interestingly, the effect of radicals on ignition is strong, outweighs the temperature deficiency and thus allows stable operation at very low NOx emissions.
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Thiruwana Kankanamage, Rumasha, John Hena Jr, Jie He, and James Rusling. "(Digital Presentation) Biocatalytic Synthesis of Chiral Compounds in Microemulsions Using Electrode-Driven Enzyme Activation." ECS Meeting Abstracts MA2022-01, no. 43 (July 7, 2022): 1870. http://dx.doi.org/10.1149/ma2022-01431870mtgabs.
Повний текст джерелаАнотація:
Biocatalysis in bicontinuous microemulsions is a promising approach for synthetic routes to regio- and stereoselective and efficient synthetic processes. Redox enzymes such as peroxidases and monooxygenases can be attached to surfaces for biocatalysis and operated in low toxicity microemulsions to enhance the dissolution of non-polar reactants, but still provide a water rich environment for the enzyme catalysis resulting in high product yield and chiral products. Here we report a new hybrid electrocatalyst system for biocatalysis using a synthetic Cu-polymer catalyst deposited on an electrode and cross-linked films of poly(L-lysine) (PLL) and redox enzymes horseradish peroxidase (HRP) and cytochrome P450 (Cyt P450) in films on oxidized pyrolytic graphite (PG) electrodes or carboxylate functionalized magnetic particles. Enzymes in these catalytic films are activated by O2 conversion to H2O2 by the Cu polymer. In microemulsions, enzyme reactions occur in a water-rich film environment with delivery of non-polar reactants from the oil-rich regions of the microemulsion. Reactions can be achieved that cannot be run in water due to lack of reactants solubility. Rotating-disk voltammetry (RDV) was used to assess catalytic activity of cross-linked enzyme/PLL films in the presence of H2O2. Activity of cross-linked HRP on magnetic particles was similar to that of 3 mg/mL of free HRP, and these HRP-beads can be used for synthesis up to 95 °C. Oxidation of 2-naphthol by HRP/PLL coated magnetic particles in microemulsions resulted in (R)- and (S)-1,1’-Bi-2-naphthol with chiral ratio determined by chiral HPLC. High product yields of oxidation products were achieved at 80 °C than 20 °C, with product analysis suggesting increasing catalytic efficiency and selectivity at higher temperatures. Additional chiral HRP reactions will be described, and cross-linked Cytochrome P450s are also being explored for stereoselective oxidation and hydroxylation of substrates including styrene, ethyl benzene and 1-tetralone.
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Zheng, Jun, and Wei Zhou. "Membrane Separation Assisted One-Pot Synthesis of Hydroxyapatite Nanorods." Advanced Materials Research 779-780 (September 2013): 251–54. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.251.
Повний текст джерелаАнотація:
In the current paper, hydroxyapatite (HAP) nanorods have been synthesized via a precipitation method with membrane separation technique assisted. The reactants were Ca(NO3)2 ·4H2O, NH4H2PO4 and ammonia water. The synthesized HAP nanocrystals were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements. Patterns of XRD exhibit that the products are indexed high-quality hexagonal crystal system nanocrystals. Though the TEM pictures, large quantities of HAP nanorods could be observed with a length of about 50-80nm and a diameter of about 10-20 nm. Preliminary study on the membrane based purifing process is also discussed by comparion the membrane of molecular weight cut-off 6000 to 10000. The resulting HAP nanorods have extensive use in biomedical area such as the bone graft substitute, drug delivery system, carrier for gene transfection, and etc.
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Chen, Peng, Hong Wang, Hongjing Liu, Zilin Ni, Jieyuan Li, Ying Zhou, and Fan Dong. "Directional electron delivery and enhanced reactants activation enable efficient photocatalytic air purification on amorphous carbon nitride co-functionalized with O/La." Applied Catalysis B: Environmental 242 (March 2019): 19–30. http://dx.doi.org/10.1016/j.apcatb.2018.09.078.
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