Insights into the Nature of Synergistic Effects in Proton-Conducting 4,4−1H,1H-Bitriazole-Poly(ethylene oxide) Composites

A nitrogen-containing heterocycle (NCH), 4,4-1H-1H-bi-1,2,3-triazole (bitriazole), capable of mimicking the hydrogen bonding of water in the solid state is synthesized and its ability to conduct protons in the presence of poly(ethylene oxides) under anhydrous conditions is investigated. Bitriazole is shown to have sufficient thermal and electrochemical stability for fuel cell applications. The composites formed between bitriazole and poly(ethylene oxides) give proton conductivities that can be described by the Vogel−Tamman−Fulcher (VTF) equation. These characteristics suggest coupling between polymer segmental motion and ion transport. The bitriazole N-H proton is shown to be the source of conductivity, and bitriazole and poly(ethylene oxides) function synergistically through specific intermolecular interactions and polymer-induced segmental motion to create a pathway for proton transport via structural diffusion

EXPERIMENTAL INVESTIGATION OF THE POTENTIAL OF LIQUIFIED PETROLEUM GAS IN VAPOUR COMPRESSION REFRIGERATION SYSTEM

The essence of refrigeration systems cannot be overemphasized especially in this part of the globe. Perishable items are to be preserved for some periods before usage while human comfort should also be also be paramount since we are in the northern hemisphere of the globe. The device hat doe this uses refrigerants as working fluids which are traditional harmful to human beings through depletion of the ozone layer. Majorly Ozone layer protects the earth from warming which could lead to flooding. Common economical refrigerants like CFCs (Chlorofluorocarbons) have been discovered to be harmful to the earth. This article therefore, experimented the quantity replacement of CFCs with Liquefied Petroleum Gas in various mixes. The LPG (Liquefied Petroleum Gas) used consists a mixture of propane and butane in the ratio 6:4 by mass. The blend of the two refrigerants were shaped essentially by blending at least two single-part refrigerants, the GWP (Global Warming Potentials) of a refrigerant mix is the mass-weighted normal of GWPs of individual parts in the mix. That is, to compute the GWP of a mix, one essentially adds the GWP of the singular parts with respect to their (GWP (LPG) x M (LPG)) + (GWP(R-134a) x M(R-134a)) = GWP (blend). From the evaluated GWP of the 6 different % mass composition, the % mass of (100%/0%) was the only refrigerant to adhere to the preferred GWP<150. The mass composition of blend (100%/0%) LPG/R-134a was first performed. In-order to achieve this, 8kg of each of the refrigerant was used. The blend was formed in an empty cylinder which was measured as 2482g with the aid of a digital beam balance, by gradually injecting LPG into the empty cylinder till the mass percentage of the 2000g entered, making the mass read as 4,482g (i.e., 2482g of the empty cylinder + 2000g of LPG). Based on the above observations, it could be inferred that the COP (Coefficient of Performance) of mixed refrigerants blends was higher than that of R-134a indicating that each of the blend exhibit higher performance. The experiment discovered that LPG could be used in the place of R134a without affecting the operation efficiency of a vapor compression refrigeration system. The study concludes that LPG offers the best alternative when the COP and flammability are combined as performance metric

Development of a Proactive Fault Diagnosis for Critical System

Large-scale network environments, such as the Internet, are characterized by the presence of various devices connected at various remote locations. There is a scenario of main office connected to different branch offices in another town and cities, with the presence of central administrative system at the main office. Any problem at branches is reported to the main office, due to availability of enough resources there. However, few support tools have been developed to allow the administrators at the central office to remotely control and monitor the computers at the branches. Even, in local area network environment, diagnosing the computers on the network is always a big problem for the administrator, as he/she moves from one computer to another, running the diagnostic program and collecting report for each machine tested. This is strenuous and time consuming. To help address these problems, I have employed the concept of mobile agent to design an architecture that can remotely perform various checks and tests on computers on network, and report its findings to the server administrator as central location. This architecture was implemented with Java, using Jini lookup service to establish communication between the computers. The agent tasks were implemented in C programming language. The result of this research work shows that the use of mobile agent for remote maintenance of computers on network was found to provide an improved, efficient, and dynamic diagnostic management system. All the same, it has proven to be a substantive contributor to efficient network management

Traumatic Tympanic Membrane perforation: An aetiological profile

<p>Abstract</p> <p>Background</p> <p>Traumatic perforation of the tympanic membrane may be due to direct or indirect source. The aim of the study is to profile the various aetiologies of traumatic tympanic membrane perforation in Ilorin, north central Nigeria.</p> <p>A retrospective review of 64 patients seen at the University of Ilorin Teaching hospital, Ilorin, Nigeria over a ten year period (January 1998 to Dec 2007) with history of traumatic tympanic membrane perforation from various causes, these also included multiply injured patients with bleeding from middle ear as part of their presentations. The data retrieved included the biodata, the clinical presentations, source of injury, the clinical findings and the treatment outcome. The data were entered into an SPSS version 11 computer soft ware and analyzed descriptively.</p> <p>Findings</p> <p>Sixty four (64) ears were analysed, Age range 6 months to 50 yrs, mean age of 29.2 yrs 7.9% of them were ≤5 years, 29.7% between 21-34 years, and 37.7% were 35 years and above. The male to female ratio was 2.5:1.0. Commonest aetiology was from slaps, then road traffic injury (RTI) in 35.9% and 23.5%, Majority of the slap injury were from fights (30.5%), security agents, senior students and cultists at schools (17.4% each). Sudden hearing loss was a typical presentation (95.3%), majority of the patient defaulted from follow up once the symptoms of bleeding and pain subsided. Only 7.8% had neomembrane formation on follow up</p> <p>Conclusion</p> <p>Traumatic perforation of the tympanic membrane is an uncommon injury that is under-reported, there is the need to educate on alternative punitive measure among students and security agents, unskilled removal of foreign body, early identification, evaluation and referral of patients reduces the attendant morbidity.</p

Development of siRNA-probes for studying intracellular trafficking of siRNA nanoparticles

One important barrier facing the delivery of short interfering RNAs (siRNAs) via synthetic nanoparticles is the rate of nanoparticle disassembly. However, our ability to optimize the release kinetics of siRNAs from nanoparticles for maximum efficacy is limited by the lack of methods to track their intracellular disassembly. Towards this end, we describe the design of two different siRNA-based fluorescent probes whose fluorescence emission changes in response to the assembly state of the nanoparticle. The first probe design involves a redox-sensitive fluorescence-quenched probe that fluoresces only when the nanoparticle is disassembled in a reductive environment. The second probe design is based on a FRET-labeled siRNA pair that fluoresces due to the proximity of the siRNA pair when the nanoparticle is intact. In both approaches, the delivery vehicle need not be labeled. The utility of these probes was investigated with a lipidoid nanoparticle (LNP) as proof-of-concept in both extracellular and intracellular environments. Fluorescence kinetic data from both probes were fit to a two-phase release and decay curve and subsequently quantified to give intracellular disassembly rate constants. Quantitative analysis revealed that the rate constant of siRNA release measured via the fluorescence-quenched probe was almost identical to the rate constant for nanoparticle disassembly measured via the FRET-labeled probes. Furthermore, these probes were utilized to determine subcellular localization of LNPs with the use of automated high-resolution microscopy as they undergo dissociation. Interestingly, this work shows that large amounts of siRNA remain inside vesicular compartments. Altogether, we have developed new siRNA probes that can be utilized with multiple nanocarriers for quantitative and qualitative analysis of nanoparticle dissociation that may serve as a design tool for future delivery systems.National Institutes of Health (U.S.) (Grant R37-EB000244)National Institutes of Health (U.S.) (Grant R01-CA132091)National Institutes of Health (U.S.) (Grant R01-CA132091)National Institutes of Health (U.S.) (Postdoctoral Fellowship

Degradable Terpolymers with Alkyl Side Chains Demonstrate Enhanced Gene Delivery Potency and Nanoparticle Stability

Degradable, cationic poly(β-amino ester)s (PBAEs) with alkyl side chains are developed for non-viral gene delivery. Nanoparticles formed from these PBAE terpolymers exhibit significantly enhanced DNA transfection potency and resistance to aggregation. These hydrophobic PBAE terpolymers, but not PBAEs lacking alkyl side chains, support interaction with PEG-lipid conjugates, facilitating their functionalization with shielding and targeting moieties and accelerating the in vivo translation of these materials.National Heart, Lung, and Blood InstituteNational Institutes of Health (U.S.) (Program of Excellence in Nanotechnology (PEN) Award, Contract #HHSN268201000045C)National Institutes of Health (U.S.) (NIH Grant R01-EB000244-27)National Institutes of Health (U.S.) (NIH Grant 5-R01-CA132091-04)National Institutes of Health (U.S.) (NIH Grant R01-DE016516-03)National Science Foundation (U.S.) (Graduate Research Fellowship)Juvenile Diabetes Research Foundation International (Grant 17–2007-1063

Traditional bone setting: an avoidable cause of major limb amputations

Background: Despite the availability of modern health care services, patients in Nigeria still seek treatment by traditional bone setters. One of the major complications of this type of native fracture treatment is limb gangrene necessitating amputations. The objective of this study was to determine the role of traditional bone setting in major limb amputations.Methods:  This retrospective study was carried out at a government orthopedic referral hospital. The study involved all patients who underwent major limb amputation between January 2015 and December 2019 in our center. Data were retrieved from medical records and operation registers. Information regarding age, sex, indications and levels of amputation and complications were studied.Results: During the study period; of the 297 major limb amputations performedd, 194 (65.3%) were due to traditional bone setting. The median age of the patients was 11.0 years (1 to 45 years) and the interquartile range was 10 years. Majority of the patients 86 (44.3%) affected were children less than 10 years of age. Male were more affected than female (M:F=1:2). Lower limb is more affected than the upper limb. The commonest amputation done was below knee amputation in 79 (40.7%) of cases. The commonest complication was surgical site infection which occurred in 32 (16.5%) patients.Conclusions: Traditional bone setting is a leading cause of major limb loss especially in children

Effect of molecular weight of amine end-modified poly(β-amino ester)s on gene delivery efficiency and toxicity

Amine end-modified poly(β-amino ester)s (PBAEs) have generated interest as efficient, biodegradable polymeric carriers for plasmid DNA (pDNA). For cationic, non-degradable polymers, such as polyethylenimine (PEI), the polymer molecular weight (MW) and molecular weight distribution (MWD) significantly affect transfection activity and cytotoxicity. The effect of MW on DNA transfection activity for PBAEs has been less well studied. We applied two strategies to obtain amine end-modified PBAEs varying in MW. In one approach, we synthesized four amine end-modified PBAEs with each at 15 different monomer molar ratios, and observed that polymers of intermediate length mediated optimal DNA transfection in HeLa cells. Biophysical characterization of these feed ratio variants suggested that optimal performance was related to higher DNA complexation efficiency and smaller nanoparticle size, but not to nanoparticle charge. In a second approach, we used preparative size exclusion chromatography (SEC) to obtain well-defined, monodisperse polymer fractions. We observed that the transfection activities of size-fractionated PBAEs generally increased with MW, a trend that was weakly associated with an increase in DNA binding efficiency. Furthermore, this approach allowed for the isolation of polymer fractions with greater transfection potency than the starting material. For researchers working with gene delivery polymers synthesized by step-growth polymerization, our data highlight the potentially broad utility of preparative SEC to isolate monodisperse polymers with improved properties. Overall, these results help to elucidate the influence of polymer MWD on nucleic acid delivery and provide insight toward the rational design of next-generation materials for gene therapy.Alnylam Pharmaceuticals (Firm)National Institutes of Health (U.S.) (Grant R01-EB000244-27)National Institutes of Health (U.S.) (Grant 5-R01-CA132091-04)National Science Foundation (U.S.). Graduate Research FellowshipNational Institutes of Health (U.S.). Ruth L. Kirschstein National Research Service Award (F32-EB011867

Mapping of aquifer units in a complex geologic terrain using natural electric field and electrical resistivity techniques

Aquifer mapping in a typical complex geologic terrain like Kobape, Southwestern Nigeria is essential to meet the needs of freshwater for domestic and industrial purposes. Natural Electric Field (NEF) measurements over eight traverses and Vertical Electrical Sounding (VES) at ten points were carried out for aquifer mapping in the area. PQWT-TC150 model of a typical water detector, which works by integrating the principle of nuclear magnetic resonance, magnetotelluric and induced polarization methods is used for the NEF measurement. It images the subsurface to a depth of 150 m while the VES was carried out to show the geoelectric layers. The results of NEF revealed the presence of confined aquifer units while the VES showed the subsurface structure to be of 3 to 4 layers viz: topsoil, sandstone, fractured layer, and fresh basement. The corresponding resistivity ranges of the geoelectric layers are 341–3596 Ωm, 1378–4333 Ωm, 635–1000 Ωm, and 3721–56382 Ωm while their thicknesses ranged from 0.5–1.6 m, 0.8–25.4 m, 2.2–19.8 m, and undeterminable fresh basement. The overall aquifer mapping in the complex geologic terrain that straddles the boundary of crystalline basement rocks and a sedimentary basin using integrated technique of NEF and VES revealed various confined aquifers. The NEF significantly showed station twenty on traverse three has a good aquifer within a fractured zone at a depth of 15 m and the same region is verified by the result obtained at VES 3, which has a fractured layer of 19.8 m thickness