bluuebunny/crossref_metadata_2025 huggingface dataset:
Implementation of a fuzzy inference system to support the evaluation of sphygmomanometers for river inspection activities in the area of legal, scientific and compliance metrology
Authors: Brito Marcio André Oliveira , Leite Jandecy Cabral , Nascimento Manoel Henrique Reis , Brito Junior Jorge de Almeida
Published: April 2024

The Amazon region has characteristics that point to logistical difficulties in meeting the demands whose inspection goal is to contribute to the economic development of the craft industry and commerce in the interior of the state, making regional products competitive, by providing technical metrological advice on procedures for verifying weighing and measuring instruments, using river vessels equipped with laboratories for testing pre-measured products, service rooms, IT and training. The Management Model for Basic River Units (UBF), aimed at carrying out inspection activities in the area of legal and scientific metrology and conformity assessment using fuzzy logic for decision-making, proposes an innovative management system for river units, focused on IPEM-AM's inspection activities using INMETRO's methodology. The approach uses fuzzy logic to improve decision-making, making it more accurate and efficient. The aim of the research is to evaluate a pressure device (sphygmomanometer) in order to fulfil inspection activities in the area of legal and scientific metrology and compliance, using fuzzy inference to support decision-making. The methodology used aims to improve the efficiency and effectiveness of inspection activities in these areas, reducing errors and optimising resources. Fuzzy logic is a suitable tool for dealing with the uncertainty and imprecision present in this context, allowing the system to make decisions that are closer to reality in accordance with the legislation. The results of the proposed model can be applied to different types of river units, helping to improve inspection processes and ensuring compliance with current rules and regulations. In addition, the use of fuzzy logic can provide more intelligent management that can be adapted to the changing conditions of the river environment according to the logistical purposes of the region.
Vitamin D Levels among Chronic Kidney Disease Patients at a Tertiary Care Hospital: A Cross-sectional Study
Authors: Sreevani M , Rao B Srinivasa , Srivanvani S
Published: April 2024

Introduction: In patients with Chronic Kidney Disease (CKD), a high prevalence of metabolite abnormalities has been observed. Numerous studies have demonstrated that individuals with reduced Glomerular Filtration Rate (GFR) are more susceptible to severe vitamin D deficiency compared to those with normal kidney function. Aim: To investigate the association between vitamin D levels and the severity of CKD among patients at Siddhartha Medical College, GGH in Vijayawada, Andhra Pradesh, India. Materials and Methods: The present hospital-based cross- sectional study was conducted at Siddhartha Medical College, GGH, Vijayawada, Andhra Pradesh, India from December 2021 to February 2022. A total of 100 CKD patients with a GFR of less than 60 mL/min/1.72 m2 were included in the study. Vitamin D levels were assessed using Chemiluminescence immunoassay (Access 2, Beckman Coulter), and vitamin D deficiency was defined as 25-OH vitamin D levels of less than 10 ng/mL, while insufficiency was defined as levels between 10 to 30 ng/mL. Statistical analysis was performed using Analysis of Variance (ANOVA) test and Pearson’s correlation test. Results: The mean age of the study population was 53.25±7.6 years, with the majority (32%) belonging to the 51-60 years age group. In terms of gender distribution, approximately three-fourths (72%) of the subjects were male. Hypertension was present in 44% of CKD patients, diabetes in 38%, and cardiovascular disease in 38%. Total 53% of CKD patients were classified as stage 4 on the Kidney Disease: Improving Global Outcome (KDIGO) CKD staging. Vitamin D deficiency was observed in 26% of patients, while 39% had insufficiency. A statistically significant association was found between the severity of CKD staging and mean vitamin D levels, with lower mean levels observed in stages 4 and 5. Conclusion: Vitamin D deficiency was present in one-fourth of the CKD patients, and it was more pronounced in advanced stages of CKD.
Analysis of Trends in Dengue Infection among Patients Attending a Tertiary Care Teaching Hospital: A Retrospective Observational Study
Authors: Jethwa Dipal K , Panwala Tanvi H , Gandhi Purvi V
Published: April 2024

Introduction: Dengue, a common mosquito-borne arboviral infection in tropical countries, presents cyclical epidemics and seasonal variations with diverse clinical outcomes. Over the past three decades, it has become endemic in India, leading to a rising mortality trend, primarily due to its severity and antibody-dependent enhancement in secondary dengue cases. Therefore, understanding the trend of dengue infection in specific geographical areas is crucial for more efficient prophylaxis. Aim: To provide a comprehensive overview of the seroprevalence of dengue virus infection in Surat district, including the trends in gender, age distribution, and seasonal variations of dengue infection from 2014 to 2021. Materials and Methods: The present retrospective observational analysis was conducted in the Department of Microbiology, Government Medical College (tertiary care teaching New Civil Hospital), Surat, Gujarat, India. A total of 31,683 blood samples were received from patients with clinical suspicion of dengue-like illness from January 2014 to December 2021. Data collection took place from March 2022 to May 2022, and the analysis was conducted in June and July 2022. All samples underwent dengue infection detection using the Enzyme-linked Immunosorbent Assay (ELISA) method by Non structural 1 (NS1) antigen detection and Immunoglobulin M (IgM) antibody detection by Mac capture ELISA. Demographic and clinical details were obtained and recorded from laboratory request forms using a structured data sheet in using Microsoft Excel software version 2013. The data were entered and analysed using EpiInfo software version 3.5.1. Results: Among the 31,683 blood samples tested, 5,994 (18.91%) cases were confirmed for dengue infection through ELISA testing. The highest number of positive cases (33.6%) was observed in the 20-29 years age group, with males outnumbering females in terms of dengue positivity at a ratio of 1.37:1. The maximum number of dengue cases occurred during the postmonsoon and early winter periods, with 96.5% of cases reported from Surat district, India. Conclusion: The rising trend of dengue infection in different age groups over the years underscores the need for continued implementation of surveillance and preventive strategies before the monsoon, aiming to reduce severe dengue infections in the future.
Morphometric Studies of Tobacco Caterpillar, [Spodoptera litura (Fabricius)] on Different Host Plants
Authors: Kumar Rishabh , Sharma S.K. , Goswami Tarak Nath , Jigyasa  , Ahmad Nawazish
Published: April 2024

Tobacco caterpillar, Spodoptera litura (Fabricius) is an economically important polyphagous pest inflicting significant economic damage to numerous field and horticultural crops. Research was conducted at the Department of Entomology, Bihar Agricultural University, Sabour, Bhagalpur, Bihar, in laboratory settings to validate the presence of this pest. The investigation involved detailed measurements of the various larval stages, pupa, adult male, and female, of tobacco caterpillar including the wingspan. The first to sixth instars of S. litura exhibited significantly greater length and width as well as width of head capsule, when reared on the tomato as a host. The pupae of S. litura reached at their maximum length and width when raised on marigold (16.75 mm and 4.36 mm), while the minimum pupal measurements (14.10 mm and 4.42 mm) was observed in case of maize. In regards to the adult moths, both male and female specimens displayed the longest length and wing span when associated with tomato (16.71 mm and 18.22 mm for length, 38.47 mm and 38.73 mm for wingspan, respectively), whereas the smallest measurements were recorded for those associated with maize (14.35 mm and 16.95 mm for length, 35.10 mm and 35.12 mm wingspan respectively). The present study confirmed the presence of S. litura that require immense attention to prepare the management strategy against it.
A Temporal Study on Incidence of Bovine Mastitis in Haryana, India
Authors: Manoj Jinu , Chhabra Rajesh , Singh Mahavir , Singh Manoj Kumar
Published: April 2024

Mastitis affects dairy animal’s productivity and causes financial losses for dairy farmers in India and across the world. In this study, a total of 52,494 quarter milk samples from 14,381 bovines were screened for the primary microorganisms causing mastitis in Hisar and adjoining districts of Haryana and their antibiotic sensitivity patterns were analyzed. The cultural positivity from subclinical form of mastitis was observed as 86.32% and 87.73% from cows and buffaloes, respectively while that from clinical mastitis was 87.36% and 87.57%. The major Gram positive bacterial pathogens associated with mastitis in the entire study period were found as Staphylococcus species with an average incidence rate of 45.53% and 44.1% from cows and buffaloes, respectively. The Streptococcus species were found to be 33.76% and 29.94% of total isolates. Escherichia coli were the most predominant Gram negative bacteria isolated (17.37% and 13.85%), thereafter Klebsiella spp. (5.54% and 5.19%) from both cows and buffaloes. A significant proportion of clinical cases of mastitis were chronic in nature from both the species of bovines. The incidence of mastitis with respect to different lactation number and lactation months was found as significant. The highest incidences of mastitis was observed in the first lactation among buffaloes (20.69%), while the maximum incidences were observed in second and third lactation in cows with 16.59% and 16.99%, respectively. However, in both the species maximum occurrence of mastitis was observed during the first lactational month. The antibiotic sensitivity patterns of most of the isolates had shown higher sensitivity towards enrofloxacin and gentamicin, while the penicillin had shown least sensitivity. The knowledge regarding the mastitis causing pathogens and their sensitivity pattern in Hisar and adjoining districts of Haryana enables the veterinarians to adopt for the proper treatment protocols and dairy farmers to assure optimal health, welfare and productivity of bovines in the State, in turn reducing antimicrobial resistance.
Design of Free-space Optical Communication Terminal Considering for Korean Domestic Weather Conditions
Authors: Song Hajun , Jang Heesuk , Yoon Taehyun
Published: April 2024

Modern military operations rely heavily on broadband communication and data transmission. Recently, the rising use of intelligent unmanned technology necessitates more frequencies. Free-space optical(FSO) communication can offer high-data-rate communications with high security and no need for licensing. Therefore, the FSO communication holds significant interest and potential in the defense industry. In this paper, we present design of a FSO communication terminal taking Korean domestic weather conditions into account. The domestic atmospheric attenuation is analyzed using several models and two-year meteorological information for a city in Korea, and this analysis is utilized to design the FSO communication terminal. The design results were verified using an FSO communication test bed, and we achieved an Ethernet bandwidth of approximately 1.86 Gbps at a distance of 1.3 km with the optical amplifier output power of the test bed set to about 20 dBm.
Copper‐Catalyzed Oxybromination and Oxychlorination of Primary Aromatic Amines Using LiBr or LiCl and Molecular Oxygen
Authors: Menini Luciano , da Cruz Santos Joyce C. , Gusevskaya Elena V.
Published: August 2008

Nuclear oxybromination of unprotected aromatic primary amines catalyzed by copper(II) acetate [Cu(OAc)2] under mild conditions has been developed, in which bromide ions are used as halogenating agents and dioxygen as a final oxidant. The catalyst shows not only high regioselectivity for para‐ or ortho‐isomers but also a remarkable chemoselectivity for monobromination. Oxychlorination of aniline can also be performed under similar conditions, albeit with lower selectivities, with N‐phenylacetamide being the main by‐product. This simple catalytic method represents ecologically benign and economically attractive synthetic pathway to expensive low‐volume aromatic haloamines.
Biphasic Hydrogenation of Olefins by Functionalized Ionic Liquid‐Stabilized Palladium Nanoparticles
Authors: Hu Yu , Yu Yinyin , Hou Zhenshan , Li Huan , Zhao Xiuge , Feng Bo
Published: August 2008

Palladium nanoparticles in the size range of 5–6 nm were prepared conveniently by reducing palladium(II) with atmospheric pressure hydrogen and stabilized by 2,2′‐dipyridylamine‐functionalized imidazolium cations according to our approach. The efficient catalytic conversion of cyclohexene into cyclohexane by the functionalized ionic liquid‐stabilized palladium nanoparticles has been performed under very mild hydrogen pressure (0.1 MPa) and at 35 °C. It was found that the concentration of palladium and the reaction temperature considerably affected the size and degree of aggregation of Pd nanoparticles in ionic liquid, which further changed the performance of the catalyst activity. The synthesized nanocatalysts can be recycled at least five times without any loss of the activity. Finally, the scope of substrates was also investigated. The excellent catalytic activity of the present system can be attributed to good stabilization and high dispersion of palladium nanoparticles.
Highly Efficient Chemoenzymatic Synthesis of Methyl (R)‐o‐Chloromandelate, a Key Intermediate for Clopidogrel, via Asymmetric Reduction with Recombinant Escherichia coli
Authors: Ema Tadashi , Ide Sayaka , Okita Nobuyasu , Sakai Takashi
Published: August 2008

Methyl (R)‐o‐chloromandelate [(R)‐1], which is an intermediate for a platelet aggregation inhibitor named clopidogrel, was obtained in >99% ee by the asymmetric reduction of methyl o‐chlorobenzoylformate (2) with recombinant Escherichia coli overproducing a versatile carbonyl reductase. A remarkable temperature effect on productivity was observed in the whole‐cell reduction of 2, and the optimum productivity as high as 178 g/L was attained at 20 °C on a 2‐g scale (1.0 M). The optimized reaction could be scaled up easily to transform 20 g of 2 in 100 mL of buffer. Three synthetic methods for 2 are compared.
Synthesis of Stereodefined Substituted Cycloalkenes by a One‐Pot Catalytic Boronation–Allylation–Metathesis Sequence
Authors: Selander Nicklas , Szabó Kálmán J.
Published: August 2008

Stereodefined cyclohexene and cyclopentene derivatives were prepared by the coupling of allylic alcohols and other allylic precursors with unsaturated aldehydes. These reactions are based on a multicatalytic one‐pot approach involving palladium pincer complex‐catalyzed boronation, allylation and ring‐closing metathesis reactions. This reaction sequence can be performed in an operationally simple procedure affording the cycloalkene products in high overall yields and excellent regio‐ and stereoselectivities. The presented procedure has a broad synthetic scope and high functional group tolerance, which allows the synthesis of bicyclic lactone and spirane skeletons and various substitution patterns including hydroxy, silyl, vinyl, allyl, and sulfonyl groups. The studied catalytic one‐pot reactions involve up to three individual processes performed by up to four acid‐ and transition metal‐catalyzed events.
Efficient Biocatalytic Synthesis of (R)‐Pantolactone
Authors: Pscheidt Beate , Liu Zhibin , Gaisberger Richard , Avi Manuela , Skranc Wolfgang , Gruber Karl , Griengl Herfried , Glieder Anton
Published: August 2008

Screening for stereoselective cyanohydrin synthesis in 96‐well plates was employed in the development of an efficient, pH‐stable hydroxynitrile lyase for the conversion of sterically hindered aliphatic aldehydes. Site‐saturation mutagenesis (SSM) resulted in a powerful catalyst for the stereoselective conversion of hydroxypivalaldehyde and pivalaldehyde to their corresponding (R)‐cyanohydrins (ee >97%) which are used as chiral building blocks (e.g., for pantothenic acid production). Furthermore, redesigning the PaHNL5 gene and improving its expression by Pichia pastoris with the help of a new PAOX1 promoter variant and the helper protein PDI (protein disulfide isomerase) led to elevated amounts of today’s most efficient biocatalyst for vitamin B5 synthesis.
Impact of Incorporating Substituents onto the P‐o‐Anisyl Groups of DiPAMP Ligand on the Rhodium(I)‐Catalyzed Asymmetric Hydrogenation of Olefins
Authors: Zupančič Borut , Mohar Barbara , Stephan Michel
Published: August 2008

The introduction of 1,2‐bis[(o‐anisyl)(phenyl)phosphino]ethane (DiPAMP) as a P‐stereogenic ligand for rhodium(I)‐catalyzed hydrogenation by Knowles et al. came after their evaluation of several diphosphines. However, no in‐depth study was carried out on incorporating various substituents on its P‐o‐anisyl groups. In this work, we have prepared a large series of enantiopure and closely related DiPAMP analogues possessing various substituents (MeO, TMS, t‐Bu, Ph, fused benzene ring) on the o‐anisyl rings. The new ligands were evaluated in rhodium‐catalyzed hydrogenation of several model substrates: methyl α‐acetamidoacrylate, methyl (Z)‐α‐acetamidocinnamate, methyl (Z)‐β‐acetamidocrotonate, dimethyl itaconate, and atropic acid. They displayed enhanced activities and increased enantioselectivities, particularly the P‐(2,3,4,5‐tetra‐MeO‐C6H)‐substituted ligand (4MeBigFUS). Interestingly enough, 88% ee was obtained in the hydrogenation of atropic acid using the Rh‐(4MeBigFUS) catalyst under mild conditions (10 bar H2, room temperature) versus 7% ee using Rh‐DiPAMP. Conversely, the ligand possessing P‐(2,6‐di‐MeO‐C6H3) groups proved to slow down considerably the hydrogenation. X‐Ray structures of their corresponding Rh complexes are presented and discussed.
Gold Catalysis: Synthesis of 3‐Acylindenes from 2‐Alkynylaryl Epoxides
Authors: Hashmi A. Stephen K. , Bührle Miriam , Salathé Ralph , Bats Jan W.
Published: August 2008

A series of 2‐alkynylaryl epoxides were prepared by a sequence of Sonogashira coupling, Wittig olefination and epoxidation or a Darzens’ glycid ester synthesis. The conversion of these substrates with gold(I) catalysts furnished 3‐acylindenes and, in occasional cases as side‐products, the products of an isomerization of the oxirane ring to a ketone. Isotope labelling of the epoxide oxygen indicates an intramolecular oxygen transfer.
Hydroxycarbamide‐induced changes in E/beta thalassemia red blood cells
Authors: Singer Sylvia T. , Vichinsky Elliott P. , Larkin Sandra , Olivieri Nancy , Sweeters Nancy , Kuypers Frans A.
Published: August 2008

In thalassemia, fetal hemoglobin (HbF) augmentation with hydroxycarbamide (also known as hydroxyurea) is not always successful. The expected parallel effects on red cell (RBC) membrane deformability, cell hydration, and membrane phospholipid organization, all important for extending RBC life span and increasing Hb, have been infrequently examined. We analyzed these characteristics in 15 nontransfused E/β0 thalassemia patients treated with HU (mean 10.2 months). Membrane deformability and cell hydration mildly improved in association with increased HbF levels approaching statistical significance (r = 0.51, P = 0.06). All measures improved considerably in splenctomized patients. These findings underscore the disappointing results of hydroxyurea treatment in clinical trials and the importance of examining the effect on RBC characteristics for the development and understanding of HbF‐enhancing agents. Am. J. Hematol., 2008. © 2008 Wiley‐Liss, Inc.
Trisomy 8 in an allogeneic stem cell transplant recipient representative of a donor‐derived constitutional abnormality
Authors: Frey Noelle V. , Leid Christopher E. , Nowell Peter C. , Tomczak Ewa , Strauser Honore T. , Kasner Margaret , Goldstein Steven , Loren Alison , Stadtmauer Edward , Luger Selina , Hexner Elizabeth , Hinkle Joanne , Porter David L.
Published: August 2008

Trisomy 8 is a common cytogenetic abnormality in myeloid malignancies. It can also be present constitutionally and is associated with a wide range of phenotypes. We report a case of a 20‐year‐old woman with acute myelogenous leukemia associated with the 11q23/MLL translocation who underwent allogeneic hematopoietic stem cell transplantation (HSCT) from a healthy, unrelated 26‐year‐old female. Cytogenetics on a bone marrow biopsy and aspirate performed 71 days after transplant to evaluate pancytopenia identified trisomy 8 in 6 of 7 cells examined. The bone marrow was hypocellular but normal by morphology and flow cytometry. Fluorescent in situ hybridization (FISH) for the original 11q23/MLL translocation was negative. Chimerism analysis using multiplex polymerase chain reaction to amplify an informative short tandem repeat demonstrated 97% donor cells. These findings were confirmed by repeat bone marrow biopsies at Day 110 after transplant and 1 year after transplant. With resolution of comorbid illness, the patient's peripheral blood counts recovered and remained normal at 1 year after HSCT. FISH analysis of a cryopreserved sample of the donor graft showed trisomy 8 in 120 of 200 cells examined. This represents the first reported case of a person with constitutional trisomy 8 mosaicism serving as a stem cell donor. The case illustrates the importance of identifying donor‐derived constitutional abnormalities to avoid the assumption that these cytogenetic abnormalities after HSCT are representative of malignant disease. Am. J. Hematol., 2008. © 2008 Wiley‐Liss, Inc.
Repeat instability in the 27–39 CAG range of the HD gene in the Venezuelan kindreds: Counseling implications
Authors: Brocklebank D. , Gayán J. , Andresen J.M. , Roberts S.A. , Young A.B. , Snodgrass S.R. , Penney J.B. , Ramos‐Arroyo M.A. , Cha J.J. , Rosas H.D. , Hersch S.M. , Feigin A. , Cherny S.S. , Wexler N.S. , Housman D.E. , Cardon L.R.
Published: August 2008

The instability of the CAG repeat size of the HD gene when transmitted intergenerationally has critical implications for genetic counseling practices. In particular, CAG repeats between 27 and 35 have been the subject of debate based on small samples. To address this issue, we analyzed allelic instability in the Venezuelan HD kindreds, the largest and most informative families ascertained for HD. We identified 647 transmissions. Our results indicate that repeats in the 27‐35 CAG range are highly stable. Out of 69 transmitted alleles in this range, none expand into any penetrant ranges. Contrastingly, 14% of alleles transmitted from the incompletely penetrant range (36‐39 CAGs) expand into the completely penetrant range, characterized by alleles with 40 or more CAG repeats. At least 12 of the 534 transmissions from the completely penetrant range contract into the incompletely penetrant range of 36‐39 CAG repeats. In these kindreds, none of the individuals with 27‐39 CAGs were symptomatic, even though they ranged in age from 11 to 82 years. We expect these findings to be helpful in updating genetic counseling practices. © 2008 Wiley‐Liss, Inc.
Studies on gas holdup in a bubble column using porous spargers with additives
Authors: Jha Abhishek , Raj Mohan B. , Chakraborty S. , Meikap B. C.
Published: August 2008

High gas holdup and uniform fine bubble generation is very essential in froth floatation cell of mineral‐based process industries. In this work, to generate uniform fine bubbles a bubble column with porous sparger have been used. The bubble column was characterized to study the effect of gas flow rate and concentration of additive solution on the performance of bubble column with porous spargers. Various types of spargers namely poly par sparger, refractory brick sparger and ceramic sparger were used to produce air bubbles in the liquid phase water and the gas holdup is estimated. The variation of gas holdup with respect to gas flow rate for different spargers and for different conditions is presented in this paper. It has been found that the gas holdup with addition of surfactants was in the range of 25–40%. The behavior of gas holdup is consistent with the existing theory and shows improvement over previous results. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd.
Frontside versus Backside SN2 Substitution at Group 14 Atoms: Origin of Reaction Barriers and Reasons for Their Absence
Authors: Bento A. Patrícia , Bickelhaupt F. Matthias
Published: August 2008

We have theoretically studied the gas‐phase nucleophilic substitution at group‐14 atoms (SN2@A) in the model reactions of Cl−+AH3Cl (A=C, Si, Ge, Sn, and Pb) using relativistic density functional theory (DFT) at ZORA‐OLYP/TZ2P. Firstly, we wish to explore and understand how the reaction coordinate ζ, and potential energy surfaces (PES) along ζ, vary as the center of nucleophilic attack changes from carbon to the heavier group‐14 atoms. Secondly, a comparison between the more common backside reaction (SN2‐b) and the frontside pathway (SN2‐f) is performed. The SN2‐b reaction is found to have a central barrier for A=C, but none for the other group‐14 atoms, A=Si–Pb. Relativistic effects destabilize reactant complexes and transition species by up to 10 kcal mol−1 (for SN2‐f@Pb), but they do not change relative heights of barriers. We also address the nature of the transformation in the frontside SN2‐f reactions in terms of turnstile rotation versus Berry‐pseudorotation mechanism.
Total Synthesis of Potent Antitumor Agent (−)‐Lasonolide A: A Cycloaddition‐Based Strategy
Authors: Ghosh Arun K. , Gong Gangli
Published: August 2008

A detailed account of the enantioselective total synthesis of (−)‐lasonolide A is described. Our initial synthetic route to the top tetrahydropyran ring involved Evans asymmetric alkylation as the key step. Initially, we relied on the diastereoselective alkylation of an α‐alkoxyacetimide derivative containing an α′ stereogenic center and investigated such an asymmetric alkylation reaction. Although alkylation proceeded in good yield, the lack of diastereoselectivity prompted us to explore alternative routes. Our subsequent successful synthetic strategies involved highly diastereoselective cycloaddition routes to both tetrahydropyran rings of lasonolide A. The top tetrahydropyran ring was constructed stereoselectively by an intramolecular 1,3‐dipolar cycloaddition reaction. The overall process constructed a bicyclic isoxazoline, which was later unravelled to a functionalized tetrahydropyran ring as well as a quaternary stereocenter present in the molecule. The lower tetrahydropyran ring was assembled by a Jacobsen catalytic asymmetric hetero‐Diels–Alder reaction as the key step. The synthesis also features a Lewis acid catalyzed epoxide opening to form a substituted ether stereoselectively.
Synthesis of Recyclable Fluorous Chiral Ligands and Evaluation of Their Catalytic Activity toward Asymmetric Addition of Dimethylzinc to Aldehydes
Authors: Sokeirik Yasser S. , Hoshina Akiko , Omote Masaaki , Sato Kazuyuki , Tarui Atsushi , Kumadaki Itsumaro , Ando Akira
Published: August 2008

The asymmetric addition of Me2Zn to aldehydes is very slow and mostly gives low ee values. Previously, we reported the synthesis of a fluorous chiral ligand, (4R,5S,α′R)‐2,2‐dimethyl‐α,α,α′‐tris(perfluorooctyl)‐2,3‐dioxolane‐4,5‐dimethanol (1 a), derived from tartarate as a chiral pool. Ligand 1 a showed high activity toward the addition of Me2Zn to aldehydes with high enantiomeric excess. However, the very high content of fluorine makes 1 a difficult to dissolve in common solvents; hence, much solvent is required, which limits its use. This report describes the modification of 1 a by replacing either the perfluorooctyl groups with shorter perfluoroalkyl ones or the acetone ketal part with cyclohexanone ketal. The perfluorobutyl analogue 1 c is much more soluble than 1 a and shows comparable asymmetric induction toward the addition of Me2Zn to aldehydes. Furthermore, 1 c has a much lower molecular weight than 1 a. This means that 1 c is used in smaller amounts (weight) than 1 a. The cyclohexanone ketal analogue 1 d is more soluble than 1 a and more easily synthesized owing to its high solubility and ease of crystallization. Ligand 1 d showed much higher asymmetric induction toward cyclohexanecarbaldehyde, a branched aldehyde, than 1 a. Thus, 1 a was modified into ligands with higher performance.
Capturing the portrait of isolated individual natural cellulose molecules
Authors: Wan Zhenzhen , Li Lu , Cui Shuxun
Published: August 2008

Natural cellulose molecules have a strong tendency of being aggregated into larger structures. Thus, the imaging of isolated individual cellulose molecules is hampered for a long time. In this work, we manage to observe, for the first time, the isolated individual natural cellulose chains on a sample surface by means of atomic force microscope. The advantage of the ionic liquid, in which natural cellulose can be molecularly dispersed, is considered to be the key point for the successful imaging. Moreover, we find that the surface charge can influence the morphology of the single cellulose chains upon adsorption. That is, on the positively charged surface, individual cellulose chains adopt an extended conformation; whereas on the negatively charged surface, a compact globule conformation is observed. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 1170–1173, 2008.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Antimicrobial peptide RP‐1 structure and interactions with anionic versus zwitterionic micelles
Authors: Bourbigot Sarah , Dodd Erin , Horwood Chrystal , Cumby Nichole , Fardy Liam , Welch William H. , Ramjan Zachary , Sharma Shantanu , Waring Alan J. , Yeaman Michael R. , Booth Valerie
Published: August 2008

Topologically, platelet factor‐4 kinocidins consist of distinct N‐terminal extended, C‐terminal helical, and interposing γ‐core structural domains. The C‐terminal α‐helices autonomously confer direct microbicidal activity, and the synthetic antimicrobial peptide RP‐1 is modeled upon these domains. In this study, the structure of RP‐1 was assessed using several complementary techniques. The high‐resolution structure of RP‐1 was determined by NMR in anionic sodium dodecyl sulfate (SDS) and zwitterionic dodecylphosphocholine (DPC) micelles, which approximate prokaryotic and eukaryotic membranes, respectively. NMR data indicate the peptide assumes an amphipathic α‐helical backbone conformation in both micelle environments. However, small differences were observed in the side‐chain orientations of lysine, tyrosine, and phenylalanine residues in SDS versus DPC environments. NMR experiments with a paramagnetic probe indicated differences in positioning of the peptide within the two micelle types. Molecular dynamics (MD) simulations of the peptide in both micelle types were also performed to add insight into the peptide/micelle interactions and to assess the validity of this technique to predict the structure of peptides in complex with micelles. MD independently predicted RP‐1 to interact only peripherally with the DPC micelle, leaving its spherical shape intact. In contrast, RP‐1 entered deeply into and significantly distorted the SDS micelle. Overall, the experimental and MD results support a preferential specificity of RP‐1 for anionic membranes over zwitterionic membranes. This specificity likely derives from differences in RP‐1 interaction with distinct lipid systems, including subtle differences in side chain orientations, rather than gross changes in RP‐1 structure in the two lipid environments. © 2008 Wiley Periodicals, Inc. Biopolymers 91: 1–13, 2009.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Inter‐residue interactions in protein structures exhibit power‐law behavior
Authors: Gao Jun , Li Zhijun
Published: August 2008

Inter‐residue interactions play an essential role in driving protein folding, and analysis of these interactions increases our understanding of protein folding and stability and facilitates the development of tools for protein structure and function prediction. In this work, we systematically characterized the change of inter‐residue interactions at various sequence separation cutoffs using two protein datasets. The first set included 100 diverse, nonredundant and high‐resolution soluble protein structures, covering all four major structural classes, all‐α, α/β, α+β, and all‐β; and the second set included 20 diverse, nonredundant and high‐resolution membrane protein structures, representing 19 unique superfamilies. It was shown that the average number of inter‐residue interactions in structures of both datasets displays the power‐law behavior. Fitting parameters of the power‐law function are directly related to the structural classes analyzed. These findings provided further insight into the distribution of short‐, medium‐, and long‐range inter‐residue interactions in both soluble and membrane proteins and could be used for protein structure prediction. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 1174–1178, 2008.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Ruthenium(II) Pyridylamine Complexes with Diimine Ligands Showing Reversible Photochemical and Thermal Structural Change
Authors: Kojima Takahiko , Morimoto Tsuyoshi , Sakamoto Taisuke , Miyazaki Soushi , Fukuzumi Shunichi
Published: August 2008

Ruthenium(II)–TPA–diimine complexes, [Ru(TPA)(diimine)]2+ (TPA=tris(2‐pyridylmethyl)amine; diimine=2,2′‐bipyridine (bpy), 2,2′‐bipyrimidine (bpm), 1,10‐phenanthroline (phen)) were synthesized and characterized by spectroscopic and crystallographic methods. Their crystal structures demonstrate severe steric hindrance between the TPA and diimine ligands. They exhibit drastic structural changes on heating and photoirradiation at their MLCT bands, which involve partial dissociation of the tetradentate TPA ligand to exhibit a facially tridentate mode accompanied by structural change and solvent coordination to give [Ru(TPA)(diimine)(solvent)]2+ (solvent=acetonitrile, pyridine). The incoming solvent molecules are required to have π‐acceptor character, since σ‐donating solvent molecules do not coordinate. The thermal process is irreversible dissociation to give the solvent‐bound complexes, which takes place by an interchange associative mechanism with large negative activation entropies. The photochemical process is a reversible reaction reaching a photostationary state, probably by a dissociative mechanism involving a five‐coordinate intermediate to afford the same product as obtained in the thermal reaction. Quantum yields of the forward reactions to give dissociated products were lower than those of the backward reactions to recover the starting complexes. In the photochemical process, the conversions of the forward and backward reactions depend on the absorption coefficients of the starting materials and those of the products at certain wavelength, as well as the quantum yields of those reactions. The reversibility of the motions can be regulated by heating and by photoirradiation at certain wavelength for the recovery process. In the bpm system, we could achieve about 90 % recovery in thermal/photochemical structural interconversion.
Characterisation of Nanohybrids of Porphyrins with Metallic and Semiconducting Carbon Nanotubes by EPR and Optical Spectroscopy
Authors: Cambré Sofie , Wenseleers Wim , Čulin Jelena , Van Doorslaer Sabine , Fonseca Antonio , Nagy Janos B. , Goovaerts Etienne
Published: August 2008

Single‐walled carbon nanotubes (SWCNTs) are noncovalently functionalised with octaethylporphyrins (OEPs) and the resulting nanohybrids are isolated from the free OEPs. Electron paramagnetic resonance (EPR) spectroscopy of cobalt(II)OEP, adsorbed on the nanotube walls by π–π‐stacking, demonstrates that the CNTs act as electron acceptors. EPR is shown to be very effective in resolving the different interactions for metallic and semiconducting tubes. Moreover, molecular oxygen is shown to bind selectively to nanohybrids with semiconducting tubes. Water solubilisation of the porphyrin/CNT nanohybrids using bile salts, after applying a thorough washing procedure, yields solutions in which at least 99 % of the porphyrins are interacting with the CNTs. Due to this purification, we observe, for the first time, the isolated absorption spectrum of the interacting porphyrins, which is strongly red‐shifted compared to the free porphyrin absorption. In addition a quasi‐complete quenching of the porphyrin fluorescence is also observed.
Cooperativity between the Dihydrogen Bond and the N⋅⋅⋅HC Hydrogen Bond in LiH–(HCN)nComplexes
Authors: Li Qing‐Zhong , Hu Ting , An Xiu‐Lin , Gong Bao‐An , Cheng Jian‐Bo
Published: August 2008

The cooperativity between the dihydrogen bond and the N⋅⋅⋅HC hydrogen bond in LiH–(HCN)n(n=2 and 3) complexes is investigated at the MP2 level of theory. The bond lengths, dipole moments, and energies are analyzed. It is demonstrated that synergetic effects are present in the complexes. The cooperativity contribution of the dihydrogen bond is smaller than that of the N⋅⋅⋅HC hydrogen bond. The three‐body energy in systems involving different types of hydrogen bonds is larger than that in the same hydrogen‐bonded systems. NBO analyses indicate that orbital interaction, charge transfer, and bond polarization are mainly responsible for the cooperativity between the two types of hydrogen bonds.
An area‐efficient switched‐capacitor relaxation oscillator with digitally controlled frequency tunability
Authors: Ausín José L. , Ramos J. , Torelli G. , Duque‐Carrillo J. F.
Published: August 2008

This paper describes a programmable low‐jitter switched‐capacitor (SC) square‐wave oscillator for the use in a variety of voice‐band signal‐processing applications. The core of the circuit is a relaxation oscillator whose oscillation frequency programmability does not resort to variations either in capacitor values or in the sampling frequency. As a result, total capacitance is reduced and, hence, silicon area is minimized while low phase jitter and high resolution programmability are achieved. Simulation results referred to the design of an SC oscillator in 0.35‐µm CMOS technology are presented to demonstrate the feasibility of the proposed approach. Copyright © 2008 John Wiley & Sons, Ltd.
The vesicular integral protein‐like gene is essential for development of a mechanosensory system in zebrafish
Authors: Chong Mabel , Liao Meijiang , Drapeau Pierre
Published: August 2008

The zebrafish hi472 mutation is caused by a retroviral insertion into the vesicular integral protein‐like gene, or zVIPL, a poorly studied lectin implicated in endoplasmic reticulum (ER)‐Golgi trafficking. A mutation in the shorter isoform of zVIPL (zVIPL‐s) results in a reduction of mechanosensitivity and consequent loss of escape behavior. Here we show that motoneurons and hindbrain reticulospinal neurons, which normally integrate mechanosensory inputs, failed to fire in response to tactile stimuli in hi472 larvae, suggesting a perturbation in sensory function. The hi472 mutant larvae in fact suffered from a severe loss of functional neuromasts of the lateral line mechanosensory system, a reduction of zVIPL labeling in support cells, and a reduction or even a complete loss of hair cells in neuromasts. The Delta‐Notch signaling pathway is implicated in cellular differentiation of neuromasts, and we observed an increase in Notch expression in neuromasts of hi472 mutant larvae. Treatment of hi472 mutant larvae with DAPT, an inhibitor of Notch signaling, or overexpression of the Notch ligand deltaB in hi472 mutant blastocysts produced partial rescue of the morphological defects and of the startle response behavior. We conclude that zVIPL‐s is a necessary component of Delta‐Notch signaling during neuromast development in the lateral line mechanosensory system. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008
Absence of arterial phenotype in mice with homozygous slc2A10 missense substitutions
Authors: Callewaert B.L. , Loeys B.L. , Casteleyn C. , Willaert A. , Dewint P. , De Backer J. , Sedlmeier R. , Simoens P. , De Paepe A.M. , Coucke P.J.
Published: August 2008

Arterial tortuosity syndrome (ATS, MIM# 208050) is a rare autosomal recessive connective tissue disease, mainly characterized by widespread arterial involvement with elongation, tortuosity, and aneurysms of the large and middle‐sized arteries (Callewaert et al., 2008, Hum Mutat 29:150–158). Recently, mutations were identified in the SLC2A10 gene encoding the facilitative glucose transporter GLUT10 (Coucke et al., 2006, Nat Genet 38:452–457). It was hypothesized that loss‐of‐function of the transporter results in upregulation of the transforming growth factor beta (TGFβ) signaling pathway (Coucke et al., 2006, Nat Genet 38:452–457). We anticipated that a mouse model would help to gain more insight in the complex pathophysiological mechanism of human ATS. Here, we report that two mouse models, homozygous respectively for G128E and S150F missense substitutions in glut10 do not present any of the vascular, anatomical, or immunohistological abnormalities as encountered in human ATS patients. We conclude that these mouse strains do not phenocopy human ATS and cannot help the further elucidation of pathogenetic mechanisms underlying this disease. genesis 46:385–389, 2008. © 2008 Wiley‐Liss, Inc.
Targeting of endothelin receptor‐B to the neural crest
Authors: Druckenbrod Noah R. , Powers Patricia A. , Bartley Christopher R. , Walker Jeffery W. , Epstein Miles L.
Published: August 2008

Endothelin receptor B (Ednrb) plays a critical role in the development of melanocytes and neurons and glia of the enteric nervous system. These distinct neural crest‐derived cell types express Ednrb and share the property of intercalating into tissues, such as the intestine whose muscle precursor cells also express Ednrb. Such widespread Ednrb expression has been a significant obstacle in establishing precise roles for Ednrb in development. We describe here the production of an Ednrb allele floxed at exon 3 and its use in excising the receptor from mouse neural crest cells by use of Cre‐recombinase driven by the Wnt1 promoter. Mice born with neural crest‐specific excision of Ednrb possess aganglionic colon, lack trunk pigmentation, and die within 5 weeks due to megacolon. Ednrb receptor expression in these animals is absent only in the neural crest but present in surrounding smooth muscle cells. The absence of Ednrb from crest cells also results in a compensatory upregulation of Ednrb expression in other cells within the gut. We conclude that Ednrb loss only in neural crest cells is sufficient to produce the Hirschsprungs disease phenotype observed with genomic Ednrb mutations. genesis 46:396–400, 2008. © 2008 Wiley‐Liss, Inc.
Generation of a conditional mutant allele for Tab1 in mouse
Authors: Inagaki Maiko , Komatsu Yoshihiro , Scott Greg , Yamada Gen , Ray Manas , Ninomiya‐Tsuji Jun , Mishina Yuji
Published: August 2008

TAK1 binding protein 1 (TAB1) binds and induces autophosphorylation of TGF‐β activating kinase (TAK1). TAK1, a mitogen‐activated kinase kinase kinase, is involved in several distinct signaling pathways including non‐Smad pathways for TGF‐β superfamily members and inflammatory responses caused by cytokines. Conventional disruption of the murine Tab1 gene results in late gestational lethality showing intraventricular septum defects and underdeveloped lung alveoli. To gain a better understanding of the roles of TAB1 in different tissues, at different stages of development, and in pathological conditions, we generated Tab1 floxed mice in which the loxP sites flank Exons 9 and 10 to remove the C‐terminal region of TAB1 protein necessary for activation of TAK1. We demonstrate that Cre‐mediated recombination using Sox2‐Cre, a Cre line expressed in the epiblast during early embryogenesis, results in deletion of the gene and protein. These homozygous Cre‐recombined null embryos display an identical phenotype to conventional null embryos. This animal model will be useful in revealing distinct roles of TAB1 in different tissues at different stages. genesis 46:431–439, 2008. Published 2008 Wiley‐Liss, Inc.
Palladastannatrane – a PdII→SnIV Dative Bond
Authors: Wagler Jörg , Hill Anthony F. , Heine Thomas
Published: August 2008

The reaction of N‐methyl‐2‐mercaptoimidazole (methimazole, Hmt) with NaN(SiMe3)2, [PdCl2(L)2] (L = PPh3, NCMe) and SnCl4 provides the novel tetrabicyclo[3.3.3.3.0] lantern compound [PdSn(μ‐mt)4Cl2] (1) in which a dative PdII→SnIV bond is housed within the cage structure. Single‐crystal X‐ray diffraction analysis reveals a Pd–Sn separation of 2.605(1) Å in this compound, and the cation [PdSn(mt)4Cl]+ was detected by ESI‐MS analysis of an acetonitrile solution of [PdSn(μ‐mt)4Cl2]. Quantum chemical analysis of the Pd–Sn bonding situation revealed predominant electrostatic interactions between the positively charged Sn and the negatively charged Pd atom. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis and Hollow‐Sphere Nanostructures of Optically Active Metal‐Free Phthalocyanine
Authors: Lv Wei , Zhang Xiaomei , Lu Jitao , Zhang Yuexing , Li Xiyou , Jiang Jianzhuang
Published: August 2008

Optically active metal‐free phthalocyanine (1) decorated with four octyl chains linked through binaphthyl units to the phthalocyanine ring was designed and prepared. This compound was characterized by a wide range of spectroscopic methods in addition to elemental analysis. By employing a solution injection method, both the (R) and (S) enantiomers self‐assemble into nanoparticles. Surprisingly, with the addition of a small amount of cetyltrimethylammonium bromide (CTAB), nanostructures with hollow‐sphere morphologies were formed. The hollow‐spherical structure was determined by transmission electronic microscopy and scanning electronic microscopy. X‐ray photoelectron spectroscopy together with FTIR spectra indicates the supramolecular structures formed from the metal‐free phthalocyanine molecules. Low‐angle X‐ray diffraction reveals the stacked phthalocyanine molecules with a face‐to‐face configuration in the nanoscale hollow spheres formed with the help of CTAB surfactant. The formation of H‐aggregates in the nanoscale hollow spheres is further confirmed by electronic absorption spectroscopic result. This work, representing the first example of controllable organic nanostructures with a hollow sphere morphology fabricated from phthalocyanine provides an effective method towards phthalocyanine hollow nanospheres.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)