bluuebunny/crossref_metadata_2025 huggingface dataset:
Paint It Black: Staining of the Yeast Cryptococcus Neoformans with India Ink
Authors: Siagian Forman Erwin
Published: May 2024

Aims: To rectify the application of negative staining using India Ink dye in order to visualize the opportunistic yeast, Cryptococcus neoformans and its capsule.
Discussion: The yeast C. neoformans is generally considered an opportunistic fungal pathogen due to its propensity to infect immunocompromised hosts, particularly those with HIV (+). This yeast responsible for causing severe disseminated Cryptococcus meningoencephalitis (CM) in humans. The type of clinical sample commonly sent for laboratory analysis of suspected patients is the cerebrospinal fluid (CSF) that usually obtained from spinal tap or lumbar puncture procedure. laboratory analysis to confirm CM initially by direct visualization of Cryptococci via light microscopy. Visualization of capsule, as the hallmark of C. neoformans is easy when appropriate number of yeasts are available in the clinical sample. India Ink is the dye of choice to stain C. neoformans and its capsule. The pathognomonic resemblance of its capsule is that of a halo appearance, whether thin or thick, surrounding the cell made visible by suspending the yeast in India ink preparations.
Conclusion: India ink stain is still widely used for the detection of cryptococci in CSF, particularly in resource-limited laboratory/health service. Its sensitivity can be improved.
Insights from Morpho-Physiological Traits Imparting Tolerance for Preharvest Sprouting of Mungbean Genotypes
Authors: Ambhore Arti Manohar , Solanke Amol P. , Lipane Rajendra R. , Adagale Rahul V. , Shamkuwar G.R.
Published: May 2024

Due to the absence of fresh seed dormancy (FSD) in mung bean seeds makes them susceptible to pre-harvest sprouting (PHS). Mung bean yield has been proved to be 60–70% reduced in response to PHS, an abiotic stress. By understanding this problem present study was carried out at at experimental field, Department of Agricultural Botany (Plant Physiology) (20.70060N, 77.03710E), PGI, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola during kharif (rainy) season 2012-13. The experiment entitled “Insights from morpho-physiological traits imparting tolerance for preharvest sprouting of munbean genotypes”. The design of experiment is Randomized block design in three replications with sixteen genotypes. It was observed that on the basis of morpho-physiological traits viz., high hard seed %, pod pubescence, lower germination in pod and seed, less seed and pod moisture genotype AKM-9801, AKM-9907, BM-2002-1 and AKM-10-05, genotypes were found to be tolerant to preharvest sprouting. And more interesting fact is the seed yield per hector found efficient in AKM-8802 and AKM-9907. So, it was found that AKM 9907 is best suitable variety of mungbean in kharif season to prevent crop from whether damage and improve yield also.
Gram Positive Cocci Associated Urinary Tract Infections, their Prevalence and Antibiotic Susceptibility Patterns
Authors: Afolabi Obe Oluwadamilare , Mutiu Wasiu Bamidele , Odulate Ibrahim Oladipupo , Akingbola Adewunmi
Published: May 2024

Background: Urinary tract infections (UTIs) are the third most common type of infection in humans globally. Gram-positive bacteria are said to be responsible for ten percent of urinary tract (UTI) infections. The study's goal was to profile gram-positive cocci-associated UTIs and their antibiogram, as they were observed at LASUTH.
Methods: This was a retrospective assessment of the Medical Microbiology Laboratory records of the LASUTH to review the in vitro antibiotic susceptibility patterns of gram-positive urinary bacterial isolates between April 2020 and March 2021. The bacteria were isolated and identified from routine urine samples using standard bacteriological methods and the API. In vitro antibiotic susceptibility test (AST) was routinely performed by the modified Kirby-Bauer disk diffusion test and susceptibility breakpoints were determined using the Clinical and Laboratory Standards Institute (CLSI) guidelines.
Results: 2,253 urine samples were processed in the medical microbiology laboratory over the one year and 662 (29.4%) samples yielded Positive cultures. Of the 662 isolates, 494 (74.6%) were gram-negative bacteria. 164 (24.8%) were gram-positive cocci while 4 (0.6%) were gram positive rod. Among the gram-positive cocci’s isolated Enterococcus faecalis had the highest frequency 58 (35.4%). Aminoglycosides (Gentamycin and Amikacin) and Linezolid antibiotics were found to be the most effective drugs against gram-positive cocci bacteria except Enterococcus spp.  For empirical treatment of Enterococcus spp in our facility Fosfomycin and Tigecycline are the best options, while for Streptococcus agalactiae associated UTI, Amikacin, Cefuroxime, Linezolid, and levofloxacin can be used for empirical treatment.
Conclusion: The prevalence rate of gram-positive cocci associated UTI in this study was 7.3% (164/2253). The emergence of drug resistance in these pathogens to commonly used antibiotics is a thing of concern. Therefore, efficient antimicrobial stewardship programmes must be in place.
The Quality Learning System Interface Factor of Success Blended Learning
Authors: Duhaim Saif M. , Taleb Dunea , Ghadhban Zahraa H.
Published: May 2024

In order to effectively deliver the learning process to both educators and learners, a high-quality LMS interface design is essential. This research's primary goal is to present a thorough understanding of the quality interface elements that influence a blended learning environment's performance. A quantitative research approach, using a questionnaire, was used. A total of 70 participants were surveyed using the questionnaire. This study shows that the fundamental predictors of quality interface were the most significant positive factor and more critical to the success of blended learning.
Tactical Aircraft Aerodynamic Integration
Authors: Hamstra Jeffrey W. , McCallum Brent N.
Published: September 2010

An overview of tactical aircraft inlet and nozzle aerodynamic integration is provided, tracing from the mid‐1970s designs, characterized by the F‐15 and F‐16, to the most current designs, characterized by the F‐22 and F‐35. Emphasis is placed on how evolving systems engineering requirements such as survivability and affordability, coupled with new technologies and development techniques, have driven changes in the form and function of inlet and nozzle systems.
Thigh muscle strength, functional capacity, and self‐reported function in patients at high risk of knee osteoarthritis compared with controls
Authors: Thorlund Jonas Bloch , Aagaard Per , Roos Ewa M.
Published: September 2010

Objective

Reduced muscle strength is suggested as a risk factor for knee osteoarthritis (OA). Meniscectomy patients have an increased risk of developing knee OA. The aim of this study was to identify reductions in different aspects of muscle strength as well as objectively measured and self‐reported lower extremity function in middle‐aged patients who had undergone a meniscectomy compared with controls.

Methods

Thirty‐one patients who had undergone surgery in 2006 and 2007 (mean ± SD age 46 ± 6 years, mean ± SD body mass index [BMI] 26 ± 4 kg/m2, and mean ± SD postsurgery 21 ± 6 months) and 31 population‐based controls (mean ± SD age 46 ± 6 years and mean ± SD BMI 26 ± 4 kg/m2) were examined for maximal muscle strength and rapid force capacity, distance achieved during the one‐leg hop test, and the maximum number of knee bends performed in 30 seconds. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was used to determine self‐reported outcomes.

Results

No differences were detected in any muscle strength variables between the operated and nonoperated leg (mean ± SD quadriceps maximum voluntary contraction of 2.80 ± 0.10 for the operated leg and 2.88 ± 0.10 for the nonoperated leg), between patients and controls (mean ± SD torque of 2.70 ± 0.09 Nm × kg‐1 for the controls; P = 0.26 for main effect leg), or in objectively measured function (P ≥ 0.27). Patients reported 10–26 points worse KOOS scores in all 5 subscales (P < 0.001).

Conclusion

Thigh muscle strength is not impaired in middle‐aged adults 2 years after resection of a degenerative tear. Our findings indicate that factors other than muscle strength are responsible for the perceived functional limitations and suggest that training to improve strength alone may not be sufficient to improve self‐reported function in patients at high risk of knee OA.
The Prospects of Carrying and Releasing Drugs Via Biodegradable Magnesium Foam
Authors: Aghion Eli , Yered Tal , Perez Yifat , Gueta Yael
Published: September 2010

Powder metallurgy technology was used to produce magnesium foams in order to evaluate their ability to perform as a solid biodegradable platform for drug delivery. The amount and delivery time of the released drug (gentamicin) was controlled by the level of space‐holding particles (spacer) that was mixed with the magnesium powder prior to the sintering process. Metallurgical examination of the magnesium foams was carried out using optical and scanning electron microscopy (SEM) and X‐ray diffraction analysis. Microtomography CT analysis was used to evaluate the structural characteristics of the magnesium foams and their internal interconnected porosity configuration. The corrosion behavior of the magnesium foams was evaluated by immersion test in a simulated physiological environment (PBS solution). The absorption of gentamicin was obtained by immersing magnesium foams in concentrated gentamicin solutions within a vacuum chamber, followed by water evaporation. The detection of gentamicin in PBS solution was carried out using a Fluorescence Polarimetry analyzer. The results show that the release profile of gentamicin from magnesium foam with 10 and 25% spacer in PBS solution was in accord with common dissolution kinetics of an active ingredient from polymeric drug delivery systems.
Conjugated Polymers: High‐Resolution Scanning Near‐Field Optical Lithography of Conjugated Polymers (Adv. Funct. Mater. 17/2010)
Authors: Credgington Daniel , Fenwick Oliver , Charas Ana , Morgado Jorge , Suhling Klaus , Cacialli Franco
Published: September 2010

The fabrication of high‐resolution nanostructures in both poly(p‐phenylene vinylene), PPV, and a crosslinkable derivative of poly(9,9′‐dioctylfluorene), F8, using scanning near‐field optical lithography, is reported. The ability to draw complex, reproducible structures with 65000 pixels and lateral resolution below 60 nm (< λ/5) is demonstrated over areas up to 20 μm × 20 μm. Patterning on length‐scales of this order is desirable for realizing applications both in organic nanoelectronics and nanophotonics. The technique is based on the site‐selective insolubilization of a precursor polymer under exposure to the confined optical field present at the tip of an apertured near‐field optical fiber probe. In the case of PPV, a leaving‐group reaction is utilized to achieve insolubilization, whereas the polyfluorene is insolubilized using a photoacid initiator to create a crosslinked network in situ. For PPV, resolubilization of the features is observed at high exposure energies. This is not seen for the crosslinked F8 derivative, r‐F8Ox, allowing us to pattern structures up to 200 nm in height.
Beyond Intercalation‐Based Li‐Ion Batteries: The State of the Art and Challenges of Electrode Materials Reacting Through Conversion Reactions (Adv. Mater. 35/2010)
Authors: Cabana Jordi , Monconduit Laure , Larcher Dominique , Palacín M. Rosa
Published: September 2010

Despite the imminent commercial introduction of Li‐ion batteries in electric drive vehicles and their proposed use as enablers of smart grids based on renewable energy technologies, an intensive quest for new electrode materials that bring about improvements in energy density, cycle life, cost, and safety is still underway. This Progress Report highlights the recent developments and the future prospects of the use of phases that react through conversion reactions as both positive and negative electrode materials in Li‐ion batteries. By moving beyond classical intercalation reactions, a variety of low cost compounds with gravimetric specific capacities that are two‐to‐five times larger than those attained with currently used materials, such as graphite and LiCoO2, can be achieved. Nonetheless, several factors currently handicap the applicability of electrode materials entailing conversion reactions. These factors, together with the scientific breakthroughs that are necessary to fully assess the practicality of this concept, are reviewed in this report.
Simultaneous heat integration and the synthesis of biogas processes from animal waste
Authors: Drobež Rozalija , Novak Pintarič Zorka , Pahor Bojan , Kravanja Zdravko
Published: September 2010

The objective of this work was to perform simultaneous heat integration and the synthesis of biogas process based on the mixed‐integer nonlinear programming (MINLP) model. A synthesis model recently developed by Drobež et al. [R. Drobež, Z. Novak Pintarič, B. Pahor, Z. Kravanja. Chem. Biochem. Eng. Q, 2009; 23, 445–459] has been upgraded for simultaneous heat integration. An industrial case study was solved in order to describe the mathematical model and to illustrate the heat‐integrated MINLP synthesis approach. The optimal solution indicates that during the synthesis of biogas process and when selecting the best auxiliary facilities significant benefit can be obtained if the selected process and auxiliary facilities are heat integrated. In this way almost the complete consumption of hot utility and 1/3 of cold utility can be saved, and thus most of the electricity and heat produced in the cogeneration system from biogas can be sold as surplus to the distribution networks. The proposed optimal synthesis of heat‐integrated biogas process may improve a company's economic performance and significantly reduce its environmental impact by converting environmentally harmful organic and animal wastes into valuable products. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
The relationship between poly(lactide‐co‐glycolide) monomer ratio, molecular weight and hollow fibre membrane scaffold morphology
Authors: Ellis Marianne J. , Chaudhuri Julian B.
Published: September 2010

The morphological characteristics of hollow fibre membrane scaffolds are fundamental to their use for cell culture in regenerative medicine applications. This paper evaluates the morphologies of hollow fibre membrane scaffolds fabricated from six commercial poly(lactide‐co‐glycolide) (PLGA) polymers with lactide : glycolide (PLA : PGA) molar ratios of 45:55, 50:50, 65:35, 75:25, 85:15 and 100:0. For polymers 65:35 to 100:0 (weight‐averaged molecular weight, Mw = 109–124 kDa), viscosity and effective porosity were inversely proportional to PLA content; surface roughness was proportional to PLA content and no conclusive trend was seen with outer skin thickness or mean pore size. 50:50 (Mw = 74 kDa) did not fit these trends while 45:55 (Mw = 12 kDa) was too inviscid to form a membrane. Effective porosity was also seen to be proportional to the polydispersity index (PDI). Further studies are required to investigate how the polymer properties at the molecular scale, i.e. transesterification and tacticity affect the membrane characteristics. The Mw, PLA : PGA ratio and PDI are key factors which can be selected to obtain the desired PLGA membrane morphology. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
A protocol for stocking hatchery reared freshwater pearl musselMargaritifera margaritifera
Authors: Bolland J. D. , Bracken L. J. , Martin R. , Lucas M. C.
Published: September 2010

Freshwater pearl mussel (Margaritifera margaritiferaL.) populations are under serious threat of extinction throughout their geographical range and only a few remnant populations are recruiting to adulthood. Consequently,M. margaritiferais classified as endangered on the International Union for Conservation of Nature Red List.

Several institutions across many countries have set up Ark sites at hatcheries to culture and rear youngM. margaritiferafrom population remnants, with the intention of stocking these juveniles into rivers. The release location must fulfill the habitat requirements for the full life‐cycle of the species, so they can contribute to the next generation and thus the long‐term recovery of the species. However, little research or advice exists about how to decide if river environments are suitable for stocking.

A protocol is presented for determining whether aM. margaritiferapopulation will benefit from stocking hatchery reared juveniles and how to identify suitable areas. Stocking locations are considered from catchment scale to microscale using water quality (reach), macrohabitat (site) and microhabitat, including physicochemical properties of the substratum (spots).

A case study of the River Esk in north‐east England, is incorporated to exemplify the myriad of considerations surrounding attempts to conserveM. margaritifera, and describes how implementation of the protocol can structure and assist stocking programmes. Copyright © 2010 John Wiley & Sons, Ltd.
Design, Synthesis, and Biological Evaluation of 1,5‐Diaryl‐1,2,4‐triazole Derivatives as Selective Cyclooxygenase‐2 Inhibitors
Authors: Jiang Bo , Zeng Yi , Li Meng‐Jie , Xu Jin‐Yi , Zhang Yong‐Na , Wang Qiu‐Juan , Sun Ni‐Yue , Lu Tao , Wu Xiao‐Ming
Published: September 2010

A series of 1,5‐diaryl‐1,2,4‐triazole derivatives were synthesized and evaluated as cyclooxygenase‐2 (COX‐2) inhibitors. The results of the preliminary biological assays in vivo showed that eight compounds 5b, 6b, 6c, 7c, 8b, 8d, 9c, and 9d have potent anti‐inflammatory activity (P < 0.01), while compounds 6b, 6c, and 9c exhibit marked potency. Compound 6c was then selected for further investigation. In the COX inhibition assay in vitro, compound 6c was identified as a potent and selective inhibitor of COX‐2 (COX‐2 IC50 = 0.37 µM; SI = 0.018), being equipotent to celecoxib (COX‐2 IC50 = 0.26 µM; SI = 0.015). In a rat carrageenan‐induced paw edema assay, 6c exhibited moderate anti‐inflammatory activity (35% inhibition of inflammation) at 2 h after administration of 15 mg/kg as an oral dose. A docking study also revealed that compound 6c binds in the active site of COX‐2 in a similar mode to that of the known selective COX‐2 inhibitor SC‐558.
Zur Anwendung der logarithmischen Normalverteilung in der Materialprüfung
Authors: Schäper Michael
Published: September 2010

Die Anwendung der logarithmischen Normalverteilung LNV in der Materialprüfung ist sinnvoll bei niedrigem Werteniveau und bei hoher Standardabweichung, wie es z. B. bei Baustoffprüfungen von Mauerwerk im Bestand häufig gegeben ist. Durchzuführen ist dabei in der Regel der Toleranzgrenzennachweis, der von der Stichprobe zum charakteristischen Wert der geprüften Baustoffeigenschaft führt.

Anwendungsnormen und ‐richtlinien führen diesen Nachweis auf Basis der LNV falsch durch, wobei sich gegenüber dem geforderten Vertrauensniveau von 75 % zu günstige charakteristische Werte ergeben. Nicht berücksichtigt wird, dass die Mengen der Merkmale sowie die der Losmittelwerte der Merkmale unterschiedliche Schiefen in der Verteilung aufweisen. Der Fehler wird in Beispielen dargelegt. Es wird eine pragmatische Zwischenlösung für die Benutzung der LNV bis zum Vorliegen der fälligen überarbeitung der Normen angegeben.

Application of the logarithmic normal distribution in material testing — Misleading norm statements resulting in faulty analyses. The application of the logarithmic normal distribution (LND) in material testing is useful in cases of large variation coefficients. The general task is, to gain from a sample an information of the characteristic value of the tested material property. For that in ge neral the one‐sided lower tolerance limit is calculated.

German application standards and norms regulate this calculation for the use of the LND not in a correct way — the resulting characteristic values for the regular demanded confidence level of 75 % are too favourable. These calculations do not respect the different distributions with different obliquity of the tested attributes in the sample on one hand and of the mean values of all samples on the other one. This mistake in using the LND is shown in examples. A pragmatic intermediate solution is given, up to the necessary revision in the norms.
Chemiluminescent Reactions of Major Importance for the Upper Atmosphere
Authors: Harteck Paul , Reeves Robert R.
Published: September 2010

A huge reservoir of oxygen atoms (and to a minor extent nitrogen atoms) is present in the upper atmosphere, extending upward from about 100 kilometers. This abundance of atoms would be sufficient for substantial illumination of the night sky if appropriate reactions could be found. In the pressure region of 1 millimeter to an atmosphere, the 2‐body collision reactions yielding light play a minor role. At pressures substantially below one millimeter, these reactions become dominant and may be the answer for this problem. A series of reactions, including nitrogen and sulfur compounds, the resulting light emission, and related problems are discussed.
Improved seeding of chondrocytes into polyglycolic acid scaffolds using semi‐static and alginate loading methods
Authors: Shahin Kifah , Doran Pauline M.
Published: September 2010

Cell seeding and attachment in three‐dimensional scaffolds is a key step in tissue engineering with implications for cell differentiation and tissue development. In this work, two new seeding methods were investigated using human chondrocytes and polyglycolic acid (PGA) fibrous mesh scaffolds. A simple semi‐static seeding method using culture plates and tissue flasks was developed as an easy‐to‐perform modification of static seeding. An alginate‐loading method was also studied, using alginate hydrogel as an adjuvant for entrapping cells within PGA scaffolds. Both the semi‐static and PGA–alginate methods produced more homogeneous cell distributions than conventional static and dynamic seeding. Using 20 × 106 cells, whereas the seeding efficiency for static seeding was only 52%, all other techniques produced seeding efficiencies of ≥ 90%. With 40 × 106 cells, the efficiency of semi‐static seeding declined to 74% while the dynamic and PGA–alginate methods retained their ability to accommodate high cell numbers. The seeded scaffolds were cultured in recirculation bioreactors to determine the effect of seeding method on cartilage production. Statically seeded scaffolds did not survive the 5‐week cultivation period. Deposition of extracellular matrix in scaffolds seeded using the semi‐static and PGA–alginate methods was more uniform compared with scaffolds seeded using the dynamic method. The new semi‐static and PGA–alginate seeding methods developed in this work are recommended for tissue engineering because they provide substantial benefits compared with static seeding in terms of seeding efficiency, cell distribution, and cartilage deposition while remaining simple and easy to execute. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Design and characterization of a new bioreactor for continuous ultra‐slow uniaxial distraction of a three‐dimensional scaffold‐free stem cell culture
Authors: Weiss S. , Henle P. , Roth W. , Bock R. , Boeuf S. , Richter W.
Published: September 2010

A computer controlled dynamic bioreactor for continuous ultra‐slow uniaxial distraction of a scaffold‐free three‐dimensional (3D) mesenchymal stem cell pellet culture was designed to investigate the influence of stepless tensile strain on behavior of distinct primary cells like osteoblasts, chondroblasts, or stem cells without the influence of an artificial culture matrix. The main advantages of this device include the following capabilities: (1) Application of uniaxial ultra‐slow stepless distraction within a range of 0.5–250 μm/h and real‐time control of the distraction distance with high accuracy (mean error −3.4%); (2) tension strain can be applied on a 3D cell culture within a standard CO2‐incubator without use of an artificial culture matrix; (3) possibility of histological investigation without loss of distraction; (4) feasibility of molecular analysis on RNA and protein level. This is the first report on a distraction device capable of applying continuous tensile strain to a scaffold‐free 3D cell culture within physiological ranges of motion comparable to distraction ostegenesis in vivo. We expect the newly designed microdistraction device to increase our understanding on the regulatory mechanisms of mechanical strains on the metabolism of stem cells. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2011
N‐Heterocyclic Carbene Mediated Activation of Tetravalent Silicon Compounds: A Critical Evaluation
Authors: Fuchter Matthew J.
Published: September 2010

An overview of the recent bibliography concerning the N‐heterocyclic carbene (NHC)‐mediated activation of tetravalent silicon compounds is presented. Diverse reactions are discussed, such as the NHC‐mediated addition of silyl pronucleophiles to a variety of electrophiles, NHC‐promoted organic and inorganic polymerisation and the reduction of CO2 by hydrosilanes as facilitated by NHCs. The review concludes with a discussion of the current knowledge regarding the role of Lewis acid–base NHC–Si interactions in the mechanistic course of these reactions.
Reversible Photoswitching of Rotaxane Character and Interplay of Thermodynamic Stability and Kinetic Lability in a Self‐Assembling Ring–Axle Molecular System
Authors: Baroncini Massimo , Silvi Serena , Venturi Margherita , Credi Alberto
Published: September 2010

We have designed, synthesized, and investigated a self‐assembling system that can be reversibly interconverted between thermodynamically stable (pseudorotaxane) and kinetically inert (rotaxane) forms by light irradiation. The system is composed of a dibenzo[24]crown‐8 ring and an axle comprised of a dibenzylammonium recognition site and two azobenzene end groups. The isomeric form of the azobenzene units of the axle has a little influence on the stability constants of the respective pseudorotaxanes but greatly affects the threading–dethreading rate constants. In fact, equilibration of the ring and the axle in its EE isomeric form occurs within seconds in acetonitrile at room temperature, whereas the ZZ axle threads–dethreads the ring at least four orders of magnitude slower. Moreover, we show that a change in the stability of the complex, achieved by deprotonating the dibenzylammonium recognition site on the axle, affects its kinetic behavior. We compare the results of these experiments with those observed upon dethreading the (pseudo)rotaxane by using a competitive guest for the ring, an approach which does not inherently destabilize the ring–axle interaction. This study outlines a general strategy for the reversible photochemical control of motion kinetics in threaded and interlocked compounds and constitutes a starting point for the construction of multicomponent structures that can behave as photochemically driven nanomachines.
ChemInform Abstract: An Efficient One‐Pot Synthesis of Substituted 2‐Aminothiophenes via Three‐Component Gewald Reaction Catalyzed by L‐Proline.
Authors: Wang Tao , Huang Xian‐Gui , Liu Jia , Li Bo , Wu Jin‐Jin , Chen Kai‐Xian , Zhu Wei‐Liang , Xu Xiao‐Yong , Zeng Bu‐Bing
Published: September 2010

A simple procedure is developed for the synthetically important scaffolds.
ChemInform Abstract: Synthesis, Anticonvulsant and Toxicity Screening of Newer Pyrimidine Semicarbazone Derivatives.
Authors: Alam Ozair , Mullick Pooja , Verma S. P. , Gilani Sadaf J. , Khan Suroor A. , Siddiqui Nadeem , Ahsan Waquar
Published: September 2010

Pyrimidine incorporated semicarbazones can be regarded as a newer class of anticonvulsants.
Oxidative dehydrogenation of propane to propene, 1: Kinetic study on V/MgO
Authors: Ramos Raquel , Pina M. Pilar , Menéndez Miguel , Santamaría Jesús , Patience Gregory S.
Published: September 2010

The reaction kinetics of the oxidative dehydrogenation of propane to propene over a V/MgO catalyst were studied. Both propane and propene oxidation kinetics were measured independently to quantify the rates of the parallel and consecutive reactions to propene and carbon oxides. Specific experiments to evaluate reaction products effects showed that water inhibited reaction rates but co‐feeding CO2or propene had no measurable effect on selectivity or conversion. Kinetic data generated under integral reactor conditions and over an inert membrane reactor have also been used to estimate the kinetic parameters. Selectivity decreased as the oxygen partial pressure increased; however, propene yield was relatively insensitive to oxygen concentration. A dual site Mars‐van Krevelen model characterizes the reaction kinetics well. The role of lattice oxygen was established by alternating pulses of propane and oxygen. This redox model is able to predict the experimental tendencies observed in the three types of reactor studied.
Synthesis of Ag/Polypyrrole Core‐Shell Nanospheres by a Seeding Method
Authors: Feng Xiaomiao
Published: September 2010

Ag/polypyrrole (PPy) core‐shell nanospheres were fabricated through the redox reaction between pyrrole monomer and silver nitrate in the presence of polyvinylpyrrolidone (PVP) and by using the Ag colloidal nanoparticles acting as the seedings. The prepared nanospheres with a shell thickness of 10–12 nm and a core diameter of 20–40 nm are uniform in size and well dispersed. The morphologies, compositions, and electrochemical activities of Ag/PPy composites were characterized by TEM, XRD, FTIR, TGA and CV. The synthetic route employed here is gentle and can be extended to prepare other conducting polymer/inorganic nanocomposites.
Evaluating the Thermal Hazard of Double‐Base Propellant SQ‐2 by Using Microcalorimetry Method
Authors: Xing Xiaoling , Xue Liang , Zhao Fengqi , Gao Hongxu , Pei Qing , Hu Rongzu
Published: September 2010

The thermal decomposition behavior of double‐base rocket propellant SQ‐2 was studied by a Calvet microcalorimeter at four different heating rates. The kinetic and thermodynamic parameters were obtained from the analysis of the heat flow curves. The critical temperature of thermal explosion (Tb), the self acceleration decomposition temperature (TSADT), the adiabatic decomposition temperature rise (ΔTad), the time‐to‐explosion of adiabatic system (t), critical temperature of hot‐spot initiation (Tcr), critical thermal explosion ambient temperature (Tacr), safety degree (SD) and thermal explosive probability (PTE) were presented to evaluate the thermal hazard of SQ‐2.
Ab initio Study of Mechanism of Forming a Germanic Hetero‐Polycyclic Compound between Germylidene (H2C=Ge:) and Acetone
Authors: Lu Xiuhui , Xu Yuehua , Lian Zhenxia , Li Yongqing
Published: September 2010

The mechanism of the cycloaddition reaction of forming a germanic hetero‐polycyclic compound between singlet germylidene (R1) and acetone (R2) has been investigated with CCSD(T)//MP2/6‐31G* method. From the surface energy profile, it can be predicted that the dominant reaction pathway for this reaction consists of three steps: (1) the two reactants (R1, R2) firstly form a twisted four‐membered ring intermediate (INT2); (2) the intermediate (INT2) reacts further with acetone (R2) to give another intermediate (INT4); (3) intermediate (INT4) isomerizes to a hetero‐polycyclic germanic compound (P4) via a transition state TS4. The presented rule of this reaction: the [2+2] cycloaddition effect between the π orbital of germylidene and the π orbital of π‐bonded compounds leads to the formation of four‐membered ring intermediate (INT2). The 4p unoccupied orbital and the lone‐pair sp electrons of Ge in the four‐membered ring intermediate (INT2) react with the π orbital and the antibonding π* orbital of π‐bonded compounds, respectively, forming the π→p and sp→ π* cyclic donor‐acceptor bonds, resulting in the generation of a stable germanic hetero‐polycyclic compound (P4).
Synthesis of Tridentate Ligands Based on Chiral Diamines and Their Application to Enantioselective Friedel‐Crafts Alkylation of Indoles with Nitroalkenes
Authors: Wu Mei , Wang Shoufeng , Xia Chungu , Sun Wei
Published: September 2010

A new type of chiral tridentate ligands were prepared and their Zn complexes were examined for the asymmetric Friedel‐Crafts alkylation of indoles with nitroalkenes, which gave rise to good yields and moderate enantioselectivities.
Copper‐Catalyzed Coupling of Thiourea with Aryl Iodides: The Direct Synthesis of Aryl Thiols
Authors: Qiao Shu , Xie Kun , Qi Junsheng
Published: September 2010

A general, economical and efficient protocol for the direct copper‐catalyzed coupling of thiourea with aryl iodides is developed and it will be potentially applied in large‐scale industry as a preferred process.
Analysis of the Volatile Components in the Leaves of Cinnamomum camphora by Static Headspace Gas Chromatography Mass Spectrometry Combined with Accurate Weight Measurement
Authors: Zhu Fengjun , Guo Yinlong
Published: September 2010

The volatile components in the leaves of C. camphora were analyzed by static headspace‐gas chromatography/mass spectrometry (HS‐GC‐MS) combined with accurate weight measurement. Accurate weight measurement obtained by Time‐of‐Flight mass spectrometry (TOF‐MS) helped to confirm the identification of volatiles in the analysis. 59 volatile components in the leaves of C. camphora were identified, which mainly included cis‐3‐hexen‐1‐ol (5.6%), 3‐hexen‐1‐ol, acetate (Z) (11.1%), β‐caryophyllene (15.4%), bicyclogermarene (8.4%), trans‐nerolidol (19.5%) and 9‐oxofarnesol (7.7%). The results show that method using HS‐GC‐MS combined with accurate weight measurement achieves reliable identification and has extensive application in the analysis of volatile components present in complex samples.
Simultaneous Determination of Caffeine and Theophylline in Human Plasma with a Weak Cation Monolithic SPE‐column
Authors: Zhu Tao , Row Kyung Ho
Published: September 2010

A simple reversed‐phase high performance liquid chromatography (RP‐HPLC) method was developed to determine the level of caffeine and theophylline in human plasma samples. The sample clean‐up step involved the on‐line solid‐phase extraction (SPE) of the analytes from plasma samples into a weak cation monolithic column using a column switching system. Separation was performed on a C18 column (5 µm, 150 mm×4.6 mm) with ultraviolet detection at 274 nm. The mobile phase consisted of methanol‐water (32/68, V/V) under isocratic conditions at a flow rate of 0.6 mL·min−1. The measured concentration of caffeine and theophylline showed a good linear relationship over the concentrations range, 0.1–80.0 µg·mL−1. The absolute recoveries ranged from 77.10% to 85.39%, and the inter‐day and intra‐day relative standard deviations (RSD) were all less than 5%. This method avoids a tedious pretreatment and provides an economic, repeatable and effective method for assaying trace drugs in biological samples.
Diagnostic Value of Poor R‐Wave Progression in Electrocardiograms for Diabetic Cardiomyopathy in Type 2 Diabetic Patients
Authors: Bildirici Ulas , Ural Dilek , Acar Eser , Agacdiken Aysen , Ural Ertan
Published: September 2010

Background

Diabetic cardiomyopathy (DCMP) is a common complication of diabetes and is associated with increased mortality. It has been suggested that a poor R‐wave progression in a resting electrocardiogram (ECG) could be a sign of cardiomyopathy.

Hypothesis

The aim of this study was primarily to analyze the relationship between poor R‐wave progression and DCMP, and the effect of poor R‐wave progression on cardiac functions in long‐term follow‐up.

Methods

Seventy type 2 normotensive diabetics (33 female, 37 male; mean age, 52.9 ± 10.4 years) were included in the study. Poor R‐wave progression in an ECG was defined as an R wave < 3 mm in V1‐3 derivations. The patients were randomized in 2 groups, which were those without (group I, n = 34) and those with poor R‐wave progression (group II, n = 36). All patients underwent conventional and tissue Doppler echocardiography and were followed in an outpatient clinic setting for 4 years.

Results

Demographic variables were similar between the 2 groups. In group II, left ventricular (LV) relaxation abnormality was more prevalent, the Tei index was higher, and in tissue Doppler mitral annulus Em velocities were significantly lower and Am velocities were higher than those with normal R‐wave progression. At the end of the 4‐year follow‐up period, LV ejection fraction was decreased in group II, whereas LV mass index and Tei index were significantly increased.

Conclusions

LV diastolic dysfunction is more frequently observed in diabetic patients with poor R‐wave progression in ECG, which may be an early sign of LV dysfunction and DCMP in diabetics. Copyright © 2010 Wiley Periodicals, Inc.

The authors have no funding, financial relationships, or conflicts of interest to disclose.
Guidelines for European workplace drug and alcohol testing in hair
Authors: Agius Ronald , Kintz Pascal
Published: September 2010

Drug and alcohol abuse is a concern for many European companies, especially those having safety‐critical jobs. It is not uncommon for European companies to establish a drug policy with little or no provision for drug testing. The European Union (EU) has launched a number of initiatives in its fight against drugs. There is, however, no specific EU legislation and no generally accepted guidelines. Since the outcome of workplace drug testing (WDT) can have serious consequences for the employee, it is of utmost importance that WDT be performed in a defined quality standard and in a legally secured way. In order to fulfil this, the European Workplace Drug Testing Society (EWDTS) has formulated WDT guidelines in order to ensure that the entire drug testing process is of high quality, accredited, and legally defensible, hence giving accurate and reliable information about employee drug use while respecting the privacy of the employee. The aim of this paper is to present the recently formulated guidelines for workplace drug testing in hair. Copyright © 2010 John Wiley & Sons, Ltd.
Simultaneous determination of nitroaromatic compounds in water using capillary electrophoresis with amperometric detection on an electrode modified with a mesoporous nano‐structured carbon material
Authors: Nie Dongxia , Li Ping , Zhang Dan , Zhou Tianshu , Liang Ying , Shi Guoyue
Published: September 2010

In this article, a carbon disk electrode modified with mesoporous carbon material (CMK‐3) was used in CE with amperometric detection system for the simultaneous determination of four types of important nitroaromatic compounds, including 2,4,6‐trinitrotoluene (TNT), 1,3,5‐trinitrobenzene (TNB), 2,4‐dinitrotoluene (DNT) and 1,3‐dinitrobenzene (DNB). Compared with the bare carbon electrode, the CMK‐3 modified electrode greatly improved the sensitivity at a relatively positive detection potential due to its excellent electrocatalytic activities, high conductivity and large effective surface area. The four analytes could be well separated and detected within 480 s. A good linear response was obtained for TNB, DNB, TNT and DNT from 8.4 to 5.0×103 μg/L, with correlation coefficients higher than 0.9992. And the detection limits were established between 3.0 and 4.7 μg/L for the four investigated nitroaromatic compounds (S/N=3). The CMK‐3‐modified electrode was successfully employed to analyze coking wastewater, tap water and river samples with recoveries in the range of 94.8–109.0%, and RSDs less than 5.0%. The presented results demonstrated that the CMK‐3‐modified carbon electrode used in CE with amperometric detection was of convenient preparation, high sensitivity and good repeatability, which could be employed in the rapid determination of practical samples.
Code acquisition in DS‐SSMA systems in the presence of multiple access interference and data modulation
Authors: Corazza Giovanni E. , Esposti Vittorio Degli
Published: September 2010

Direct‐Sequence Spread Spectrum Multiple Access (DS‐SSMA) techniques are being proposed for modern personal and mobile radio communication networks. Fast and accurate acquisition of synchronism between the received code sequence and the locally generated sequence plays a fundamental role in the successful utilization of any code division multiple access technique. In this paper, the performance of the code acquisition sub‐system is analysed in the presence of multiple access interference, data modulation and noise. The effect of interference from other codes is analysed without resorting to a Gaussian approximation; this approach allows the evaluation of the properties of different families of codes. Results of the analysis are presented for Maximal Length Shift Register (MLSR), Gold and Kasami sequences, with and without verification mode, with absorbing and non absorbing false alarm state.
Simulation analysis of loss characteristics in ATM switching systems by R1022
Authors: Habermann Reinhard
Published: September 2010

In this paper the results of a simulation analysis concerning the loss characteristics in ATM‐switching systems are presented. The basic model used for the simulation is able to cover a wide range of ATM‐traffic mixes and switching architectures. Due to special simulator techniques (parallel simulation) the model can be applied within a reasonable range of load and loss probability figures. A new set of global and connection‐related performance parameters has been defined in order to evaluate the distribution of loss cases over time. The obtained results show that bursty traffic influences directly the global and connection‐related loss characteristics. The burstiness of traffic mixes results in the accumulation of losses so that losses appear in bursts with long lossfree intervals between the bursts. It is also shown that the service‐related loss probability depends on the load parameters of the service.
Performance design of an ATM node on the basis of the experience from the BLNT RACE project
Authors: Heiss Herbert , Wallmeier Eugen , Rigolio Giancarlo , Toniatti Tiziana
Published: September 2010

This paper contains recent results of ATM traffic studies obtained by the project partners involved in the Broadband Local Network Technology (BLNT) RACE project 1012. These studies are concerned with congestion notification methods, problems in conjunction with Peak Cell Rate control and the analysis of multi‐stage switching systems. The implications of these studies on the design and performance of an ATM node are discussed.
A new approach to sequential detection
Authors: Metzger Kurt
Published: September 2010

The known suboptimal sequential detection methods need a minimum‐phase signal as input for achieving good performance. As a consequence the received signal must be first transformed to minimum‐phase by an adaptive prefilter if simplified detection methods are applied. This roundabout way is avoided in a novel algorithm for sequential detection, where the metric calculation itself is fitted to the special situation of the compare‐and‐select procedure. The detection method uses two different metrics, one for comparing paths, which have merged in a common trellis‐state, the other for comparing paths which have just emerged from a common state. In this way the usual adaptive prefilter can be saved, because the proposed detector does not require a minimum‐phase signal at its input. Simulation results show excellent management of distorted and noisy signals.
An algorithm for optimal load balancing in a multiple GI/G/1 queueing system
Authors: Zhang Zhigang , Hartmann Harro L. , He Hucang , Bai Zhe
Published: September 2010

The issue of optimal load balancing has been raised in several important engineering fields such as the file management in a data base, the job control in a multiple processor system or the flow assignment in a packet switched data network. By modeling the subsystems as multiple GI/G/1 queues and applying known approximations and decomposition methods, the system mean response time is expressed as a function of the load allocation. To find the optimal load balancing, the convexity property is first studied with respect to the type of the arrival process of the system. We give then an efficient algorithm which finds for the convex case the global and for the non‐convex case a local minimum. Some important properties of the multiple Gl/G/1 queueing system are revealed with several numerical examples.
Multiple cochannel interference effects in a first‐order phase‐locked loop
Authors: Hasan Pavel
Published: September 2010

The phase error statistics of a first‐order phase‐locked loop in the presence of multiple cochannel CW interference and additive noise is derived. An accurate numerical solution based on the nonlinear theory is outlined. Approximate analytical formulae are obtained from the linear theory for low interference‐to‐signal ratios. The linear analysis shows that the phase error statistics in the linear approximation depends only on the interference‐to‐signal ratio independent of the number of interferers and the interference power distribution. Errors appeared in some of the numerical results reported by Yoon and Lindsey [1] in the single interferer case are identified and corrected. Numerical examples for N = 2, 3, and 6 interferers of equal power are given. The effect of the interference power distribution is investigated.
Decision feedback equalization of HDSL using a generalized adaptive IIR delay filter
Authors: Ghavami Mohammad , Nader‐Esfahani Said , Rupprecht Werner
Published: September 2010

A decision feedback equalization scheme comprising of a generalized adaptive infinite impulse response delay filter in the feedback path is proposed and used for equalization of high‐rate digital subscriber loops including severe intersymbol interference and near‐end crosstalk colored noise. The feedback filter compensates the long postcursor intersymbol interference due to the high sampling rate and is composed of parallel sections having one, two or four coefficients and a delay element. The structures of the sections are determined adaptively and in a step‐by‐step procedure. Because of the parallel and, at most, two‐pole sections of the generalized adaptive infinite impulse response delay filter, the stability monitoring requires essentially no computations. To reduce the noise enhancement effect of the prefilter, an adaptive noise predictor is also used. Computer simulation results demonstrate the performance of the proposed structure compared to the conventional decision feedback equalizer with a finite impulse response feedback filter. The main advantage of the proposed system is the significant reduction in the number of coefficients and consequently the adaptation time.
Mean time to lose lock of the first‐and second‐order modified code tracking loop used in spread spectrum systems
Authors: Welti A. L. , Bernhard U. P.
Published: September 2010

Pseudonoise (PN) code tracking loops are essential in various direct‐sequence spread‐spectrum (DSSS) systems for both, communication and navigation applications. This paper shows how to optimize the so‐called modified code tracking loop (MCTL) of first‐ and second‐order by using the mean time to lose lock (MTLL) as a performance criterion. The state equation of the first‐order MCTL is related to the Smoluchowski ‐ Kramers approximation of a second‐order system described by the Langevin equation of motion. For such a specific system, the MTLL is known by the work of Kramers. In case of the second‐order type II loop (having two perfect integrators), which cannot be described by the Langevin equation, the computation of the MTLL is based on the singular perturbation method. Optimal parameters maximizing the MTLL under the constraint of Doppler effects and the channel noise are derived for both type of loops, resulting in very simple expressions that can be used immediately for a practical loop design. Measurements performed for the first‐order MCTL verify the theoretical optimal loop parameters and indicate that the time to lose lock is exponentially distributed. Monte Carlo simulations confirm also very well the theoretical results in case of a second‐order loop and hence, show that the application of the singular perturbation method yields an excellent approximation of the MTLL.