bluuebunny/crossref_metadata_2025 huggingface dataset:
The organization development consultancy agenda for development programmes in Ghana
Authors: Darko N. Darko
Published: April 2024

Despite its humanistic values, organisation development consultancy practice appears to be facing implementation challenges, especially regarding development programmes in the public and private sectors. OD's agenda for development programmes is to ensure its values yield benefits that could be translated into effective programmes. This is because all the development programmes involve change, which in one way or the other had not been managed effectively in the past, given the many fads of change management. The main objective of this study was to assess the benefits and challenges of OD as a consultancy practice, and create the needed awareness to enable consultants; policy makers and managers encourage its use in development programmes. This case study, through snowball sampling procedure, recorded the perceptions of 35 respondents, 16 of which are OD practitioners and 19 non OD practitioners. The findings confirmed that OD as a consultancy methodology has enormous potentials to facilitate development programmes in Ghana. However, challenges such as reliance on 'expert' consultants and opposition by policy makers need to be overcome through education and awareness creation ifOD is to survive as a consultancy practice. Far reaching implications for OD practice were provided.
Despite its humanistic values, organisation development consultancy practice appears to be facing implementation challenges, especially regarding development programmes in the public and private sectors. OD's agenda for development programmes is to ensure
Authors: Danquah P. Danquah
Published: April 2024

Fundamental to the Network Administrator's consideration of risk on a network are issues of security namely; confidentiality, integrity and availability of information assets. The ability to effectively and efficiently manage the network and make room for growth without degradation in network performance are equally considerable concerns. The segmentation of a significantly large Local Area Network with a possible annual growth rate of over 10% is undoubtedly the surest way to effectively manage the network, ensure security of information assets and make it scalable. This paper seeks to assess the Pentecost University College(PUC) campus network at Sowutuom to determine how optimally segmented it is and the most practical option of using Virtual LANs to optimize the segmentation for effective and efficient security, management and scalability. Based on the information gathered and analysis carried out on the network, a proposal is advanced to enhance the segmentation of the campus network with an eye towards the future growth.
Service quality and customer satisfaction in healthcare delivery: A comparative study of public and private hospitals in Ghana
Authors: Andoh-Quainoo L. Andoh-Quainoo , Asante R. Asante , Ofori-Amanfo J. Ofori-Amanfo , Ofori-Nyarko E. Ofori-Nyarko , Antwi-Boasiako A. Antwi-Boasiako
Published: April 2024

The 21st century has witnessed a dramatic growth in the services sector. One service sector that has advanced significantly is the health sector. In Ghana, health care delivery, particularly infrastructural development, has improved significantly over the past 10 to 15 years. However, its reflection in quality health service to the customer and customer satisfaction has not received much attention. This study was carried out to explore how satisfied the health service customer is and the quality of services delivered. It was also to compare public and private hospitals on these variables. A survey instrument on variables of service quality and customer satisfaction was used to collect data from some selected private and public hospitals within the Accra Metropolis. It was hypothesized that there would be no significant differences between public and private hospitals on service quality and customer satisfaction. The study however, found that there are differences in sendee quality and customer satisfaction dimensions between public and private hospitals. The findings suggest that in general quality of service delivery and customer satisfaction are relatively better in private hospitals than public hospitals, and that public hospitals need more improvement in service quality and customer satisfaction.
The Concept of Using the Excess Rate of Return in the Study of the Impact of EU ETS on the Value of Enterprises
Authors:   University of Szczecin, Poland Institute of Economics and Finance, Witkowski Paweł
Published: April 2024

The aim of the study is to assess the impact of the EU ETS on the profitability and the excess rate of return (ERR), which is the difference between profitability and the cost of capital. The study was conducted between 2008 and 2016 on a sample of 91 very large companies covered by the EU ETS. Models for panel data were used for the analysis. No statistically significant relationship between emission allowances and return on equity was found. However, a statistically significant relationship between emission allowances and ERR was detected. This could mean that companies were able to pass on the cost of emission allowances to their counterparties. However, greenhouse gas emissions entail greater exposure to the price risk of emission allowances, which the companies were unable to diversify, resulting in an increase in the cost of equity. Moreover, the study shows that the effect of emission allowances on the value of companies may not be symmetrical, as the variable under study was only statistically significant when it took on positive values (GHG emissions were higher than the allocation). As proven, an analysis of the excess returns can help to explain some of the inconsistencies and contribute to a better understanding of the impact of the EU ETS on the value of companies. The research carried out helps to answer the question of who bears the costs of reducing greenhouse gases and is it true that there are no costs for companies and therefore the introduction of the EU ETS has not affected their value. The conclusions of this study may be of interest to policymakers, investors but also to the public.
Rastros documentales de la (des)aparición de cuerpos: inhumaciones irregulares y antropología forense en un cementerio público de Córdoba
Authors: Paiaro Melisa , Sánchez Ana
Published: April 2024

This article reflects on the extensive use of irregular burials in public cemeteries as a method of disappearance/elimination of bodies during the last civic-military dictatorship in Argentina. Drawing on a historical-anthropological perspective, it investigates a paradigmatic case: the discovery of one of the largest mass graves in Latin America, located in the San Vicente Cemetery in the city of Córdoba, Argentina. The underlying assumption guiding the analysis is that irregular burial involved the intervention of bureaucratic-administrative instances linked to the regular handling of corpses—hospitals, morgues, and public cemeteries—resulting in the existence of documentary traces that currently account for its use and extent. The article begins with the description of a letter written in 1980 by morgue workers and a newspaper article about the first identification in Córdoba, serving as temporal markers of a lengthy search process. The geographical and historical reconstruction of San Vicente and its burial practices configure it as a territory of marginalities and impurities, as a receiver of bodies of the sick, the poor, and also “subversive delinquents.” Analyzed as cultural artifacts, the morgue's entry books and the 1980 letter reveal different aspects of the irregular burial practice and how the bodies of the murdered were incorporated into the routines of state agencies. Such records were crucial in the forensic anthropological work of searching for and locating the large mass grave. The article is framed among studies focusing on the “legal” and “administrative” forms of state repression and terror. It seeks to highlight the importance of preliminary investigation and interdisciplinarity in the application of forensic anthropology, not only in the analyzed geographical area but also in clarifying the multiple violences that permeate the region.
The MODY-associated KCNK16 L114P mutation increases islet glucagon secretion and limits insulin secretion resulting in transient neonatal diabetes and glucose dyshomeostasis in adults
Authors: Nakhe Arya Y. , Dadi Prasanna K. , Kim Jinsun , Dickerson Matthew T. , Behera Soma , Dobson Jordyn R. , Shrestha Shristi , Cartailler Jean-Philippe , Sampson Leesa , Magnuson Mark A. , Jacobson David A.
Published: April 2024

The gain-of-function mutation in the TALK-1 K
+
channel (p.L114P) is associated with maturity-onset diabetes of the young (MODY). TALK-1 is a key regulator of β-cell electrical activity and glucose-stimulated insulin secretion. The
KCNK16
gene encoding TALK-1 is the most abundant and β-cell–restricted K
+
channel transcript. To investigate the impact of
KCNK16
L114P on glucose homeostasis and confirm its association with MODY, a mouse model containing the
Kcnk16
L114P mutation was generated. Heterozygous and homozygous
Kcnk16
L114P mice exhibit increased neonatal lethality in the C57BL/6J and the CD-1(ICR) genetic background, respectively. Lethality is likely a result of severe hyperglycemia observed in the homozygous
Kcnk16
L114P neonates due to lack of glucose-stimulated insulin secretion and can be reduced with insulin treatment.
Kcnk16
L114P increased whole-cell β-cell K
+
currents resulting in blunted glucose-stimulated Ca
2+
entry and loss of glucose-induced Ca
2+
oscillations. Thus, adult
Kcnk16
L114P mice have reduced glucose-stimulated insulin secretion and plasma insulin levels, which significantly impairs glucose homeostasis. Taken together, this study shows that the MODY-associated
Kcnk16
L114P mutation disrupts glucose homeostasis in adult mice resembling a MODY phenotype and causes neonatal lethality by inhibiting islet insulin secretion during development. These data suggest that TALK-1 is an islet-restricted target for the treatment for diabetes.
Early acquisition of S-specific Tfh clonotypes after SARS-CoV-2 vaccination is associated with the longevity of anti-S antibodies
Authors: Lu Xiuyuan , Hayashi Hiroki , Ishikawa Eri , Takeuchi Yukiko , Dychiao Julian Vincent Tabora , Nakagami Hironori , Yamasaki Sho
Published: April 2024

SARS-CoV-2 vaccines have been used worldwide to combat COVID-19 pandemic. To elucidate the factors that determine the longevity of spike (S)-specific antibodies, we traced the characteristics of S-specific T cell clonotypes together with their epitopes and anti-S antibody titers before and after BNT162b2 vaccination over time. T cell receptor (TCR) αβ sequences and mRNA expression of the S-responded T cells were investigated using single-cell TCR- and RNA-sequencing. Highly expanded 199 TCR clonotypes upon stimulation with S peptide pools were reconstituted into a reporter T cell line for the determination of epitopes and restricting HLAs. Among them, we could determine 78 S epitopes, most of which were conserved in variants of concern (VOCs). After the 2nd vaccination, T cell clonotypes highly responsive to recall S stimulation were polarized to follicular helper T (Tfh)-like cells in donors exhibiting sustained anti-S antibody titers (designated as “sustainers”), but not in “decliners”. Even before vaccination, S-reactive CD4
+
T cell clonotypes did exist, most of which cross-reacted with environmental or symbiotic bacteria. However, these clonotypes contracted after vaccination. Conversely, S-reactive clonotypes dominated after vaccination were undetectable in pre-vaccinated T cell pool, suggesting that highly-responding S-reactive T cells were established by vaccination from rare clonotypes. These results suggest that
de novo
acquisition of memory Tfh-like cells upon vaccination may contribute to the longevity of anti-S antibody titers.
Hammerhead-type FXR agonists induce an enhancer RNA Fincor that ameliorates nonalcoholic steatohepatitis in mice
Authors: Chen Jinjing , Wang Ruoyu , Xiong Feng , Sun Hao , Kemper Byron , Li Wenbo , Kemper Jongsook
Published: April 2024

The nuclear receptor, farnesoid X receptor (FXR/NR1H4), is increasingly recognized as a promising drug target for metabolic diseases, including nonalcoholic steatohepatitis (NASH). Protein-coding genes regulated by FXR are well known, but whether FXR also acts through regulation of long non-coding RNAs (lncRNAs), which vastly outnumber protein-coding genes, remains unknown. Utilizing RNA-seq and global run-on sequencing (GRO-seq) analyses in mouse liver, we found that FXR activation affects the expression of many RNA transcripts from chromatin regions bearing enhancer features. Among these we discovered a previously unannotated liver-enriched enhancer-derived lncRNA (eRNA), termed FXR-induced non-coding RNA (Fincor). We show that Fincor is specifically induced by the hammerhead-type FXR agonists, including GW4064 and tropifexor. CRISPR/Cas9-mediated liver-specific knockdown of Fincor in dietary NASH mice reduced the beneficial effects of tropifexor, an FXR agonist currently in clinical trials for NASH and primary biliary cholangitis (PBC), indicating that amelioration of liver fibrosis and inflammation in NASH treatment by tropifexor is mediated in part by Fincor. Overall, our findings highlight that pharmacological activation of FXR by hammerhead-type agonists induces a novel eRNA, Fincor, contributing to the amelioration of NASH in mice. Fincor may represent a new drug target for addressing metabolic disorders, including NASH.
Guanidine production by plant homoarginine-6-hydroxylases
Authors: Funck Dietmar , Sinn Malte , Forlani Giuseppe , Hartig Jörg S
Published: April 2024

Metabolism and biological functions of the nitrogen-rich compound guanidine have long been neglected. The discovery of four classes of guanidine-sensing riboswitches and two pathways for guanidine degradation in bacteria hint at widespread sources of unconjugated guanidine in nature. So far, only three enzymes from a narrow range of bacteria and fungi have been shown to produce guanidine, with the ethylene-forming enzyme (EFE) as the most prominent example. Here, we show that a related class of Fe2+- and 2-oxoglutarate-dependent dioxygenases (2-ODD-C23) highly conserved among plants and algae catalyze the hydroxylation of homoarginine at the C6-position. Spontaneous decay of 6-hydroxyhomoarginine yields guanidine and 2-aminoadipate-6-semialdehyde. The latter can be reduced to pipecolate by pyrroline-5-carboxylate reductase but more likely is oxidized to aminoadipate by aldehyde dehydrogenase ALDH7B in vivo. Arabidopsis has three 2-ODD-C23 isoforms, among which Din11 is unusual because it also accepted arginine as substrate, which was not the case for the other 2-ODD-C23 isoforms from Arabidopsis or other plants. In contrast to EFE, none of the three Arabidopsis enzymes produced ethylene. Guanidine contents were typically between 10 and 20 nmol*(g fresh weight)-1 in Arabidopsis but increased to 100 or 300 nmol*(g fresh weight)-1 after homoarginine feeding or treatment with Din11-inducing methyljasmonate, respectively. In 2-ODD-C23 triple mutants, the guanidine content was strongly reduced, whereas it increased in overexpression plants. We discuss the implications of the finding of widespread guanidine-producing enzymes in photosynthetic eukaryotes as a so far underestimated branch of the bio-geochemical nitrogen cycle and propose possible functions of natural guanidine production.
Age-related decline in blood-brain barrier function is more pronounced in males than females in parietal and temporal regions
Authors: Shao Xingfeng , Shou Qinyang , Felix Kimberly , Ojogho Brandon , Jiang Xuejuan , Gold Brian T , Herting Megan M , Goldwaser Eric L , Kochunov Peter , Hong Elliot , Pappas Ioannis , Braskie Meredith , Kim Hosung , Cen Steven , Jann Kay , Wang Danny JJ
Published: April 2024

The blood-brain barrier (BBB) plays a pivotal role in protecting the central nervous system (CNS), and shielding it from potential harmful entities. A natural decline of BBB function with aging has been reported in both animal and human studies, which may contribute to cognitive decline and neurodegenerative disorders. Limited data also suggest that being female may be associated with protective effects on BBB function. Here, we investigated age and sex-dependent trajectories of perfusion and BBB water exchange rate (kw) across the lifespan in 186 cognitively normal participants spanning the ages of 8–92 years old, using a non-invasive diffusion-prepared pseudo-continuous arterial spin labeling (DP-pCASL) MRI technique. We found that the pattern of BBB kw decline with aging varies across brain regions. Moreover, results from our DP-pCASL technique revealed a remarkable decline in BBB kw beginning in the early 60 s, which was more pronounced in males. In addition, we observed sex differences in parietal and temporal regions. Our findings provide in vivo results demonstrating sex differences in the decline of BBB function with aging, which may serve as a foundation for future investigations into perfusion and BBB function in neurodegenerative and other brain disorders.
A detailed study of resampling algorithms for cyberattack classification in engineering applications
Authors: Mogollón Gutiérrez Óscar , Sancho Núñez José Carlos , Ávila Mar , Caro Andrés
Published: April 2024

The evolution of engineering applications is highly relevant in the context of protecting industrial systems. As industries are increasingly interconnected, the need for robust cybersecurity measures becomes paramount. Engineering informatics not only provides tools for knowledge representation and extraction but also affords a comprehensive spectrum of developing sophisticated cybersecurity solutions. However, safeguarding industrial systems poses a unique challenge due to the inherent heterogeneity of data within these environments. Together with this problem, it’s crucial to acknowledge that datasets that simulate real cyberattacks within these diverse environments exhibit a high imbalance, often skewed towards certain types of traffics. This study proposes a system for addressing class imbalance in cybersecurity. To do this, three oversampling (SMOTE, Borderline1-SMOTE, and ADASYN) and five undersampling (random undersampling, cluster centroids, NearMiss, repeated edited nearest neighbor, and Tomek Links) methods are tested. Particularly, these balancing algorithms are used to generate one-vs-rest binary models and to develop a two-stage classification system. By doing so, this study aims to enhance the efficacy of cybersecurity measures ensuring a more comprehensive understanding and defense against the diverse range of threats encountered in industrial environments. Experimental results demonstrates the effectiveness of proposed system for cyberattack detection and classification among nine widely known cyberattacks.
Studies on Seasonal Variation of Zooplankton Population in Elanthakulam, Palayamkottai, Tirunelveli District, India
Authors: Kumar Ananth , Manikandaraja .
Published: April 2024

A study of the zooplankton population in Elanthakulam pond, Tirunelveli District, and the plankton samples were collected during the winter season (August 2017–October 2017). Seasonal changes in the pattern of the zooplankton population have been driven by a combination of abiotic and biotic factors. Hence, the present study was undertaken to assess the zooplankton population in the Elanthakulam pond. The results indicate that 10 species belonging to four genera were recorded during the period of study. Out of 10 species, 4 belonged to rotifers, 3 belonged to caldoserans, 2 belonged to copepods, and one species belonged to Ostracoda. The present study concludes that zooplankton were not at their maximum in the monsoon season because of unfavourable environmental conditions, and they also slightly declined in August and September and increased again in October.
Hydrochar Derived from Sewage Sludge and Water Hyacinth and Its Characterization
Authors: S Paul Sebastian, , Parameswari E , Kalaiselvi P. , Davamani V. , Vijayakumar M.
Published: April 2024

Population and urbanization increase the sewage generation. Sewage treatment plant (STP) generates the sewage sludge. Agricultural runoff and sewage water discharge into water bodies proliferates the growth of water hyacinth and creates environmental issues. Managing the sewage sludge and water hyacinth are difficult task because of high water content, environmental concerns, regulatory measures and high operational cost. Hydrothermal carbonization (HTC) converts the wet biomass into condensed solid product called hydrochar at moderate temperature range of 180 – 250°C under auto generated pressure. Through HTC process, the sewage sludge and water hyacinth were mixed and converted into hydrochar @ temperature of 200℃ and 4h resident time with L/S ratio of 9:1. The produced hydrochar showed desired functional groups viz., CH – methyl groups, C-O-C – alcohol groups, esters, ethers and Oxygenic functional groups (-C=O, -OH, -CO-O, C-O-C) with particle size of 494.8 nm, BET surface area of 369.70 m2 g-1, Zeta Potential of -27.9 mV. The hydrochar recorded slightly acidic pH (5.8) with appreciable levels of C (24.4%), N (2.51%), P (0.44%), K (0.98%), Ca (1.24%), Mg (0.68%). These properties of sewage sludge and water hyacinth derived hydrochar exhibits its potential use in agricultural and environmental applications.
Application Analysis of New Civil Engineering Materials
Authors: Hengjin Gao
Published: April 2024

In recent years, with the continuous development of the technical level in the field of construction, new civil engineering materials have a wide range of applications in various fields, the limitations of traditional building materials lead to the need for more sustainable and cost-effective alternative materials to meet the construction needs of civil engineering. This paper analyzes the new civil engineering materials, discusses the characteristics of high-performance concrete, new steel and composite materials, and analyzes the application strategies of new civil engineering materials in practical application fields, aiming to provide constructive suggestions for improving the construction quality of civil engineering and the application efficiency of new materials.
High‐Performance Liquid Chromatography/Mass Spectrometry in Peptide and Protein Analysis
Authors: Shen Tun‐Li
Published: October 2008

Since the 1970s, high‐performance liquid chromatography/mass spectrometry (HPLC/MS) has gone through many stages of development. The main technical challenge has been the coupling of liquid chromatography (LC) systems with mass spectrometers. Soft ionization techniques that have contributed to HPLC/MS for peptide and protein study include fast atom bombardment (FAB), matrix‐assisted laser desorption/ionization (MALDI), and electrospray ionization (ESI). Among these techniques, FAB was developed first and used extensively in the 1980s; it lacked the sensitivity of the other two more recent techniques. MALDI and ESI are comparable in terms of sensitivity and the types of biomolecules that can be analyzed. However, MALDI has the slight advantage of being more tolerant to salts and able to analyze complex mixtures. On the other hand, the ability of ESI to interface mass spectrometry (MS) directly with LC makes it extremely useful for protein and peptide analysis. Another advantage that ESI offers is its ability to produce multiply charged protein ions, which allows the observation of large proteins with mass analyzers of limited mass range. In this article, we discuss the experimental parameters that are important in HPLC/MS and the considerable progress made in ESI source design and capillary HPLC/MS.

In the study of natural and synthetic peptides, HPLC/MS has been used to separate, characterize, and sequence the peptides being investigated. In protein analysis, HPLC/MS is most useful in characterizing protein posttranslation modification such as glycosylation and phosphorylation. We discuss specific HPLC/MS methods for detecting glycopeptides and phosphopeptides during chromatographic separation by monitoring marker ions: Hex
+
(
m
/
z
163), HexNAc
+
(
m
/
z
204), NeuAc
+
(
m
/
z
292), and HexHexNAc
+
(
m
/
z
366) for glycopeptides, and PO
2
−
(
m
/
z
63) and PO
3
−
(
m
/
z
79) for phosphopeptides. Another important application of HPLC/MS is in proteomic analysis. Here, the most significant development in the first decade of proteomics analysis has been the implementation of MS as the primary analytical technique to identify proteins separated by two‐dimensional polyacrylamide gel electrophoresis (2‐D/PAGE). Additionally, the need to identify gel‐separated proteins has promoted various MS‐based protein database search strategies. These include peptide mass mapping using proteolytic peptide masses for database search and using peptide fragmentation data obtained from tandem mass spectrometry (MS/MS) to search protein sequence databases. Finally, we examine the more recent advances in proteomics in integrating multidimensional LC–MS/MS and the analysis of large‐scale proteomics datasets.
Fluorescence in Organized Assemblies
Authors: Memon Najma , Balouch Aamna , Hinze Willie L.
Published: October 2008

This article provides an overview of the general properties of organized assembly (ordered media) systems, such as aqueous surfactant and bile salt micelles, lipid (liposomes) and surfactant vesicles, and cyclodextrins (CDs), and summarizes their utilization to enhance the performance of analytical fluorescence measurements. In many instances, organic molecules and metal complex species when included within a CD cavity or solubilized and bound to surfactant aggregates exhibit enhanced fluorescence, improving detectability of such analytes. The altered microenvironment within the organized medium can impede the interfering action of other species (inorganic or organic) present in the sample matrix, which often improves the selectivity of the analytical method. These benefits of improved sensitivity and selectivity arise from the compartmentalization, isolation, and shielding of the excited singlet state of the guest analyte from quenching and nonradiative decay processes, as well as preventing side reactions that otherwise can occur in bulk solution (or sample matrix). Organic solvents or time‐consuming extraction steps can also be avoided, owing to the increased solubility of nonpolar organic or inorganic reagents and/or analyte molecules in water in the presence of the organized medium, allowing the use of an aqueous medium to perform the procedure. The possibility of conducting reactions and forming fluorescent organic or metal chelates in micellar (or other organized) media that are not observed in a bulk homogeneous solvent system serves to expand the scope of possible chemistries for design/development of new, unique, and improved fluorescent assays. Examples of fluorescent methods for determination of both organic and inorganic analytes are provided, which serve to illustrate the advantages and benefits accrued from the use of the micelles, vesicles, liposomes, or CDs in such procedures, along with experimental considerations and cautions in utilizing organized media.
Nuclear Magnetic Resonance Instrumentation
Authors: Bai Shi
Published: October 2008

The nuclear magnetic resonance (NMR) spectrometer consists of a superconducting magnet, a sample probe, a radio‐frequency (RF) transmitter, a receiver, and a computer for instrument control and data processing. The superconducting magnet provides an ultrastable magnetic field in the central volume of the magnet. To maintain the current, the solenoid that produces the field is immersed in liquid helium to maintain the superconducting state. Surrounding the magnet volume is a set of vacuum jackets and a liquid nitrogen–filled volume to isolate the low‐temperature regions from room temperature. The magnet has a bore to house the sample probe and a room‐temperature shim (RTS) coil assembly to reduce inhomogeneity of the magnetic field across the active sample volume. The sample to be analyzed is usually dissolved in a deuterated solvent and is contained in a specially ground glass tube that is inserted into the volume of the probe coil. RF pulses, from one or a set of high‐power transmitters, are applied to the sample through the RF coil that surrounds the active sample area to perturb the sample. The RF pulses are controlled to ensure precise frequency, phase, duration, and amplitude of the RF voltage. The response of the sample is gathered by recording the induced voltage across the RF coil. The response (the signal) is digitized as a so‐called free induction decay (FID) with a high‐performance RF receiver including a preamplifier, an amplifier, and an analog‐to‐digital converter (ADC). By using Fourier transformation (FT), the time‐domain FID is converted into the frequency‐domain spectrum, often known as the NMR spectrum.
Activation Analysis of Large Samples
Authors: Bode Peter
Published: October 2008

There is a trend in many analytical techniques towards the use of smaller sizes of the test portion, and sometimes submilligram amounts are being used. The limitation to the size of the test portion can pose the analyst with problems when the amount of material collected is large. Subsampling and preparation of a representative test portion may be difficult if homogenization is impossible or extremely expensive, or if homogenization introduces contamination. An alternative approach has been introduced in the 1990s by the development of large sample neutron activation analysis (LSNAA), later followed by large sample photon activation analysis. These techniques are capable of direct analysis of samples with masses of hundreds of grams to several kilograms. Though the principles and physics of large sample activation analysis are thoroughly understood, the method is still not as versatile or applicable as, for example, normal small sample neutron activation analysis. In this article, the physics of LSNAA is described, including methods of calibration. Examples are given of irradiation and counting facilities and the special aspects of quality control are discussed. Several examples are given of applications of large sample analysis, e.g., for studies related to electronic waste, complete archaeological and cultural artifacts, high‐purity materials, and materials of irregular shape.
Activity Determination and Localization of Radioactive Point Source in a Large Medium
Authors: Alfassi Zeev B.
Published: October 2008

The activity and localization of a small‐sized radioactive source in a large medium was studied for various cases by the simultaneous use of several detectors. The γ‐emitting source and the neutron‐emitting source were both studied. This also led to an α‐emitting source, which cannot be detected from outside of the medium unless the neutrons from their (α,n) reaction with low Z elements are detected. A special actual case of commercial lung counter with four semiplanar HPGe detectors is described in detail. For large boxes, NaI(Tl) detectors were used for γ measurements measuring only the full‐energy peaks. For neutrons, only thermal neutrons were measured with3He detectors. To increase the fraction of the thermal neutrons and to protect the measurer, the sample was surrounded by a fence made of 5‐cm polypropylene.
Microwave‐assisted synthesis, spectroscopy and biological aspects of binuclear titanocene chelates of isatin‐2,3‐bis(thiosemicarbazones)
Authors: Banerjee Priyanka , Pandey Om P. , Sengupta Soumitra K.
Published: October 2008

The reactions of bis(cyclopentadienyl)titanium(IV) chloride with a new class of bis(thiosemicarbazones) (H2L), derived by condensing isatin with different N(4)‐substituted thiosemicarbazides, have been studied both by a conventional stirring method and also using microwave technology. Binuclear products of type [{(η5‐C5H5)2TiCl} 2(L)] have been isolated in both cases. Tentative structural conclusions are drawn for the reaction products based upon analysis, electrical conductance, magnetic moment and spectral (UV‐visible, IR, 1H NMR and 13C NMR) data. FAB mass spectra of these compounds were also recorded to confirm the binuclear structures. Studies were conducted to assess the growth inhibiting potential of the ligands and complexes against various fungal, viral and bacterial strains. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis, structural characterization and cytotoxic activity of diorganotin(IV) complexes of N‐(5‐halosalicylidene)tryptophane
Authors: Tian Laijin , Yang Hongjun , Zheng Xiaoliang , Ni Zhonghai , Yan Dongmei , Tu Linglan , Jiang Jianzhuang
Published: October 2008

Four new diorganotin(IV) complexes of N‐(5‐halosalicylidene)tryptophane, R2Sn[5‐X‐2‐OC6H3CHNCH(CH2Ind)COO] [Ind = 3‐indolyl; R, X = Et, Cl (1); Et, Br(2); n‐Bu, Cl (3); n‐Bu, Br (4)], were synthesized and characterized by elemental analysis, IR and NMR (1H, 13C and 119Sn) spectra. The crystal structures of complexes 1–3 were determined by X‐ray single crystal diffraction and showed that the tin atoms are in a distorted trigonal bipyramidal geometry and form five‐ and six‐membered chelate rings with the tridentate ligand. Intermolecular weak interactions in 1–3 link molecules, respectively, into a two‐dimensional array, a one‐dimensional infinite chain and a one‐dimensional double‐chain supramolecular structure. Bioassay results of the compounds indicated that the dibutyltin complexes 3 and 4 have potent in vitro cytotoxic activity against two human tumor cell lines, CoLo205 and Bcap37, while the diethyltin complexes 1 and 2 display weak cytotoxic activity. Copyright © 2008 John Wiley & Sons, Ltd.
Solvent vapor‐induced self assembly and its influence on optoelectronic conversion of poly(3‐hexylthiophene): Methanofullerene bulk heterojunction photovoltaic cells
Authors: Zhao Yun , Guo Xiaoyang , Xie Zhiyuan , Qu Yao , Geng Yanhou , Wang Lixiang
Published: October 2008

Nanoscale‐phase separation of electron donor/acceptor blends is crucial for efficient charge generation and collection in polymer bulk heterojunction photovoltaic cells. We investigated solvent vapor annealing effect of poly(3‐hexylthiophene) (P3HT)/methanofullerene (PCBM) blend on its morphology and optoelectronic properties. The organic solvents of choice for the treatment have a major effect on the morphology of P3HT/PCBM blend and the device performance. Ultraviolet‐visible absorption spectroscopy shows that specific solvent vapor annealing can induce P3HT self‐assembling to form well‐ordered structure; and hence, the absorption in the red region and the hole transport are enhanced. The solvent that has a poor solubility to PCBM would cause large PCBM clusters and result in a rough blend film. By combining an appropriate solvent vapor treatment and post‐thermal annealing of the devices, the power conversion efficiency is enhanced. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A Feasibility Study on the Use of Li4V3O8 as a High Capacity Cathode Material for Lithium‐Ion Batteries
Authors: Ng See‐How , Tran Nicolas , Bramnik Kirill G. , Hibst Hartmut , Novák Petr
Published: October 2008

Li4V3O8 materials have been prepared by chemical lithiation by Li2S of spherical Li1.1V3O8 precursor materials obtained by a spray‐drying technique. The over‐lithiated vanadates were characterised physically by using scanning electron microscopy (SEM) and X‐ray diffraction (XRD), and electrochemically using galvanostatic charge‐discharge and cyclic voltammetry measurements in both the half‐cell (vs. Li metal) and full‐cell (vs. graphite) systems. The Li4V3O8 materials are stable in air for up to 5 h, with almost no capacity drop for the samples stored under air. However, prolonged exposure to air will severely change the composition of the Li4V3O8 materials, resulting in both Li1.1V3O8 and Li2CO3. The electrochemical performance of these over‐lithiated vanadates was found to be very sensitive to the conductive additive (carbon black) content in the cathode. When sufficient carbon black is added, the Li4V3O8 cathode exhibits good cycling behaviour and excellent rate capabilities, matching those of the Li1.1V3O8 precursor material, that is, retaining an average charge capacity of 205 mAh g−1 at 2800 mA g−1 (8C rate; 1C rate means full charge or discharge of a battery in one hour), when cycled in the potential range of 2.0–4.0 V versus Li metal. When applied in a non‐optimised full cell system (vs. graphite), the Li4V3O8 cathode showed promising cycling behaviour, retaining a charge capacity (Li+ extraction) above 130 mAh g−1 beyond 50 cycles, when cycled in the voltage range of 1.6–4.0 V, at a specific current of 117 mA g−1 (C/3 rate).
In vivo conversion of BM plasmacytoid DC into CD11b+ conventional DC during virus infection
Authors: Liou Li‐Ying , Blasius Amanda L. , Welch Megan J. , Colonna Marco , Oldstone Michael B. A. , Zuniga Elina I.
Published: October 2008

DC are a highly heterogeneous population that plays a critical role in host defense. We previously demonstrated that virus infection induces BM plasmacytoid DC (pDC) differentiation into CD11b+ conventional DC (cDC) upon in vitro culture with Fms‐like tyrosine kinase 3 ligand (Flt3L). Here we use immunoglobulin D‐J rearrangements and pDC adoptive transfer to provide definitive proof supporting BM pDC conversion into CD11b+ cDC during in vivo viral infection. We show that in vivo BM pDC conversion into CD11b+ cDC relates to enhanced ability to prime virus‐specific T cells. Furthermore, we demonstrate that in vivo pDC conversion does not rely on viral infection of BM pDC, but instead is mediated by type I IFN signaling. Finally, by exploiting recently identified pDC‐specific Ab, we provide further characterizations of the BM pDC fraction that exhibits this broader developmental plasticity. Collectively, these data indicate that BM pDC actively contribute to the CD11b+ cDC pool during in vivo viral infection and delineates molecular, functional, and phenotypic features of this novel developmental pathway.
NK cells and Treg cells: A fascinating dance cheek to cheek
Authors: Zimmer Jacques , Andrès Emmanuel , Hentges François
Published: October 2008

NK cells and Treg cells are both a major focus of current immunological interest. It is therefore not surprising that their interactions have been and continue to be investigated. New and challenging studies have been published in the past couple of years that confirm and extend previous knowledge in this area. In this Viewpoint, we will briefly review and comment on the recent literature
regarding NK/Treg interactions.
Non‐cytotoxic protection by human NK cells in mucosal secondary lymphoid tissues
Authors: Münz Christian
Published: October 2008

Even though NK cells have been named for their spontaneous cytotoxicity, a large subpopulation of human NK cells primarily responds to activation with cytokine secretion and not killing. These CD56brightCD16− NK cells are abundant in secondary lymphoid tissues, can restrict pathogens that have breached mucosal barriers, and assist Th1 polarization during immune response priming. This exciting new aspect of NK‐cell biology is discussed in this viewpoint.
Killers and beyond: NK‐cell‐mediated control of immune responses
Authors: Andoniou Christopher E. , Coudert Jérôme D. , Degli‐Esposti Mariapia A.
Published: October 2008

Effective immunity requires coordinated activation of innate and adaptive immune responses. NK cells are principal mediators of innate immunity, able to respond to challenge quickly and generally without prior activation. The most acknowledged functions of NK cells are their cytotoxic potential and their ability to release large amounts of cytokines, especially IFN‐γ. Recently, it has become clear that NK cells are more than assassins. Indeed, NK cells play critical roles in shaping adaptive immunity.
Cobalt and Copper Coordination Polymers Containing Acetylacetonato‐Derived Ligands and Bidentate Pyridine Coligands: Synthesis, Crystal Structures and Magnetic Properties
Authors: Atienza Javier , Gutiérrez Angel , Felisa Perpiñán M. , Sánchez Ana E.
Published: October 2008

One‐dimensional chain derivatives of the general formula [M(acac)2(μ‐bipyridine)] were obtained from (acetylacetonato)cobalt(II) or (trifluoromethylacetylacetonato)copper(II) derivatives and bipyridine‐like bridging ligands: 1,2‐bis(4‐pyridyl)ethane, 4,4′‐bpa (1, Co; 2, Cu), trans‐1,2‐bis(4‐pyridyl)ethylene, 4,4′‐bpe (3, Co; 4, Cu), 1,2‐bis(2‐pyridyl)ethylene, 2,2′‐bpe (5, Co) or pyrazine (7, Cu). The reaction of the copper parent derivative with 2,2′‐bpe gives rise, however, to a dimeric species [{Cu(tfacac)2}2(μ‐2,2′‐bpe)] (6). Derivatives 4–7 were characterized by X‐ray crystallography, which showed linear (4, 7) or zigzag chains (5), depending on the bipyridine ligand shape. In the chain complexes, the metal centre is six‐coordinate; the oxygen donor atoms of the acetylacetonato ligands occupy the equatorial positions and the bridging bipyridine ligands are in trans axial positions. Compound 6 forms a dimer with the two copper atoms in a square pyramidal environment, in which the nitrogen atoms of the bridging 2,2′‐bpe ligand occupy the apical position in each pyramid. Magnetic susceptibility studies of the cobalt compounds are dominated by the spin–orbit coupling characteristic of this metal ion. At low temperatures and in the copper derivatives, weak antiferromagnetic interactions along the chain were observed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Recent Advances in the Design and Coordination Chemistry of Heteroscorpionate Ligands Bearing Stereogenic Centres
Authors: Otero Antonio , Fernández‐Baeza Juan , Lara‐Sánchez Agustín , Tejeda Juan , Sánchez‐Barba Luis Fernando
Published: October 2008

This review concerns the recent studies carried out by our research group and others aimed at the design of heteroscorpionate ligands based on bis(pyrazol‐1‐yl)methane‐containing stereogenic centres. The capability of these systems to stabilize chiral complexes from early to late transition metals, through their behaviour as multidentate hybrid ligands, is also described.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Construction of a Statistical Evaluation Model Based on Molecular Centrality to Find Retrosynthetically Important Bonds in Organic Compounds
Authors: Tanaka Akio , Kawai Takashi , Matsumoto Tsutomu , Fujii Mihoko , Takabatake Tetsuhiko , Okamoto Hideho , Funatsu Kimito
Published: October 2008

For the purpose of finding retrosynthetically important bonds in a molecule, a new evaluation score has been defined through a logistic regression analysis of known reactions stored in reaction databases. We conceived that reaction center bonds in reaction databases describe one of the most retrosynthetically important bonds for each product structure. The derived statistical equation consists of bond centrality and bond dissociation energy terms. The equation shows that synthetically useful bonds tend to be more central in a molecule and to be weaker bonds. Coefficients in two statistical equations derived from two different reaction data sets are quite similar to each other. From a comparison of molecular complexities and validation with 35 complicated organic compounds, the evaluation equation was proved to be useful. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis and NMDA Receptor Affinity of Ring and Side Chain Homologues of Dexoxadrol
Authors: Sax Michael , Fröhlich Roland , Schepmann Dirk , Wünsch Bernhard
Published: October 2008

Novel dexoxadrol derivatives with an expanded oxygenheterocycle (1,3‐dioxane instead of 1,3‐dioxolane), an enlarged distance between the two heterocycles, and an additional oxo group in the 4‐position of the piperidine ring were synthesized and pharmacologically evaluated. The synthesis comprises a hetero‐Diels–Alder reaction of imines with Danishefsky's diene (3), followed by a Lewis acid catalyzed conjugate reduction of the resulting dihydropyridones and hydrogenolytic debenzylation. The required aldehydes were synthesized by transacetalization of benzophenone dimethyl acetal (8) with pentane‐1,3,5‐triol (7), butane‐1,2,4‐triol (15), and 4‐benzyloxybutane‐1,3‐diol (31), respectively, and subsequent Swern oxidation. Homodexoxadrols39were synthesized by the Cagliotti method with the use ofp‐toluenesulfonylhydrazide and NaBH4for the removal of the oxo group. The diastereomers were separated and the relative configuration was assigned by X‐ray crystal structure analysis and comparison of spectroscopic and chromatographic data. Receptor binding studies with the radioligand [3H]‐(+)‐MK‐801 demonstrated that an expanded O‐heterocycle, an enlarged distance between the heterocycles, and an additional oxo group led to a considerable loss of affinity towards the phencyclidine binding site of the NMDA receptor.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
1,2,4,5‐Tetrakis(tetramethylguanidino)benzene: Synthesis and Properties of a New Molecular Electron Donor
Authors: Peters Anastasia , Kaifer Elisabeth , Himmel Hans‐Jörg
Published: October 2008

The molecular electron donor 1,2,4,5‐tetrakis(tetramethylguanidino)benzene (ttmgb) was synthesised by reaction between 1,2,4,5‐tetraaminobenzene and 2‐chloro‐1,1′,3,3′‐tetramethylformamidinium chloride. Protonation and oxidation of the molecule were analysed. In the course of titration of initially yellow‐coloured solutions of ttmgb with HCl intense and fully reversible colour changes were observed; the di‐ and tetraprotonated forms are green‐ and blue‐coloured, respectively. The tetraprotonated molecule crystallised with Cl–, and the diprotonated molecule crystallised with PF6– as counterions. Oxidation, which already occurs slowly in air, was followed by CV measurements. Oxidation with I2 leads to deeply green‐coloured solutions, from which purple‐black crystals of (ttmgb)(I3)2 of metallic appearance and a layer structure were obtained. The analysis of the molecular structure shows that the π system has rearranged with loss of the aromatic benzene system. Quantum chemical calculations suggest ttmgb to be an excellent two‐electron donor superior even to the “organic sodium” tetraazafulvalene in the gas phase. However, in polar solvents (modelled with the COSMO model) the situation changes (in line with the experimental results from CV measurements), as the dication of tetraazafulvalene is considerably more solvent stabilised than [ttmgb]2+. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)