bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of host weight on the distribution of Argulus foliaceus (L.) (Crustacea, Branchiura) within a fish community
Authors: Walker Peter , Harris Jack , Velde Gerard , Wendelaar Bonga Sjoerd
Published: June 2008

Spatial heterogeneity is a feature common to many ecosystems. Aquatic organisms typically exhibit this heterogeneous distribution but to date little is known about the distribution of many common parasite species within water bodies. In this study the distribution of Argulus foliaceus (L.), an ectoparasitic crustacean, on different sized hosts within a mixed species fish community was determined. Different fish species exhibited differences in their louse burdens (prevalence and intensity). The highest prevalence of A. foliaceus was observed on fish species dominated by larger individuals (i.e. Cyprinus carpio, Abramis brama and Tinca tinca). C. carpio and A. brama also exhibited the highest mean louse intensities. Infested fish were generally heavier than uninfested conspecifics. Differences in the weight of uninfested and infested fish were significant (P<0.05) for the whole fish community samples and the Scardinius erythrophthalmus, A. brama and C. carpio samples. There was also a general pattern of increasing infestation intensity with an increase in host body weight, with significant correlations for the whole fish community for S. erythrophthalmus, A. brama and C. carpio samples. In addition there were significant differences in parasite prevalence and intensity between different host weight groups and larger (heavier) fish appeared to be more prone to infestation by A. foliaceus.
Two new species of the quill mite genus Aulobia Kethley, 1970 (Acari, Syringophilidae) associated with sunbirds (Passeriformes, Nectariniidae)
Authors: Skoracki Maciej , Głowska Eliza
Published: June 2008

Two new quill mite species parasitizing sunbirds (Nectariniidae) are described: Aulobia nectariniae sp. nov. from the Olive-backed Sunbird Cinnyris jugularis (L.), from the Black Sunbird Leptocoma sericea (Lesson), and Aulobia anthreptes sp. nov. from Plain-throated Sunbird Anthreptes malacensis. The family Nectariniidae is a new host group for syringophilid mites.
Experimental hymenolepiasis of rats: preliminary data on histopathological changes of visceral organs
Authors: Movsesyan Sergey , Jivanyan Karine , Chubaryan Flora , Malczewski Andrzej , Terenina Nadezhda , Petrossyan Rosa , Ter-Oganyan Karine
Published: June 2008

Pathomorphological changes of intestine, liver, spleen and adrenals of rats experimentally infected with Hymenolepis diminuta are described 24 days post infection. Major structural alterations in intestinal wall include lesions of the mucosa, fusions of villi, damage of the epithelial layer and its replacement by flattened cells with pycnotic nuclei. In addition, tunica muscularis and tunica submucosa become thicker and there are numerous lymphocytes among enterocytes. At moderate infections, the changes in the spleen indicate activation of the lymphopoiesis and enhanced protective functions while, in heavily infected rats, the B zone of the spleen showed signs of emaciation. Liver histology of infected rats showed dilatation of sinusoids and the presence of destructive alterations in the parenchyma, necrotic cells and cells with pycnotic nuclei; in heavily infected animals, the necrotic cells were grouped in foci. In adrenal glands, alterations concern mostly zona fascicularis, which is interpreted as mobilization of cytoplasmic lipid inclusions in order to increase the intensity of the steroid hormone synthesis. The degree and character of histopathological changes depended on the intensity of infection.
Studies on the development and role of some cell-mediated immune responses in experimental toxocarosis in mice
Authors: Wnukowska Natalia , Dzbeński Tadeusz
Published: June 2008

The studies were undertaken to investigate the development of some cell-mediated immune responses in experimental toxocarosis in mice and to assess the influence of these responses on the course of infection. Mice were infected orally with 350 eggs of Toxocara canis and reinfected with the same dose of parasites after 8 weeks. Groups of infected animals were killed each week of the experiments to obtain spleens, livers and brains for further studies. Lymphocytes from removed spleens were analysed by flow-cytometry for CD4 and CD8 expression and cultured in vitro to measure their responses to Concanavalin A and excretory-secretory (ES) antigen of T. canis in a lymphocyte transformation test. Pieces of livers were used to prepare paraffin sections to be stained later with haematoxylin and eosin, whereas whole brains of the infected animals were examined for the presence of parasite larvae. The results of the studies showed depression of T-cell responses to ConA in early stages of infection and significant increase in the blastogenic responses to the ES antigen from week 4 following infection. The depression of T-cell responses was accompanied by lowered CD4+/CD8+ ratio resulting from increased percentages of CD8+ T cells. Histopathological examination of liver sections revealed trapping of larvae in T. canis reinfected mice. The intensity of infection as measured by larval recoveries from the brains of mice increased gradually up to the 8th week of infection, but did not show significant changes after reinfection, testifying to the development of long-lasting protective immunity during primary infection.
Oligopeptidase B-2 from Leishmania amazonensis with an unusual C-terminal extension
Authors: Matos Guedes Herbert , Carvalho Rafael , Oliveira Gomes Daniel , Rossi-Bergmann Bartira , De-Simone Salvatore
Published: June 2008

The oligopeptidase B serine protease is an important virulence factor and therapeutic target in Trypanosoma infections. Recently, the Leishmania major Genome Project identified a new oligopeptidase B that was denominated oligopeptidase B-like, herein named oligopeptidase B-2. In this study, a complete open reading frame of oligopeptidase B-2 from Leishmania amazonensis (PH8 strain) was amplified by PCR using primers designed for the oligopeptidase B-2 gene of L. major. The 2,715 bp fragment coded for a protein of 905 amino acids with a predicted molecular mass of 103,918.9 Da and theoretical pI of 5.82. The encoded protein displayed ∼96% identity with L. major and ∼75% identity with Trypanosoma cruzi and T. brucei oligopeptidases B-2, and ∼21% identity with Escherichia coli and L. amazonensis classical oligopeptidase B. An unusual C-terminal extension was found in relation to the classical trypanosomatid oligopeptidase B. By sequence alignment, we determined a catalytic triad (Ser 629, Asp 717 and His 758), S1 subsite (Glu 674 and Glu 676) and suggest a difference in the S2 subsite of L. amazonensis oligopeptidase B-2. We also found that the oligopeptidase B-2 gene is expressed in all cycle stages of L. amazonensis. A phylogenetic analysis indicated that oligopeptidase B-2 is a new member of oligopeptidase B.
Helminth parasites of two sympatric lizards, Enyalius iheringii and E. perditus (Leiosauridae), from an Atlantic Rainforest area of southeastern Brazil
Authors: Vrcibradic Davor , Anjos Luciano , Vicente Joaquim , Bursey Charles
Published: June 2008

We present data on helminths harboured by two sympatric species of Enyalius Wagler, 1830 (E. iheringiii Boulenger, 1885 and E. perditus Jackson, 1978) from the Atlantic Rainforest of the Ilha de São Sebastião, in São Paulo state, southeastern Brazil. Six helminth species were found in the hosts: five nematodes (Cosmocerca sp., Oswaldocruzia burseyi Durette-Desset, Anjos et Vrcibradic, 2006, Oswaldocruzia fredi Durette-Desset, Anjos et Vrcibradic, 2006, Rhabdias sp., and Strongyluris oscari Travassos, 1923), and one acanthocephalan (Acanthocephalus sp.). Overall helminth prevalences were relatively high for both species [6/6 (100%) for E. iheringii and 9/14 (64%) for E. perditus]. The helminth assemblages from both host species were depauperate and dominated by generalist helminths with direct life-cycles.
Identification and characterization of 31 isolates of Borrelia burgdorferi (Spirochaetales, Spirochaetaceae) obtained from various hosts and vectors using PCR-RFLP and SDS-PAGE analysis
Authors: Žákovská Alena , Janouškovcová Eva , Pejchalová Kateřina , Halouzka Jiří , Dendis Miloš
Published: June 2008

Borrelia burgdorferi sensu lato, the etiologic agent of Lyme borreliosis, circulates between ticks and vertebrate hosts. Two main genospecies typically occur in the Czech Republic Borrelia garinii and Borrelia afzelii, transmitted generally by Ixodes ricinus (L., 1758) ticks. The aim of our study was to identify spirochaete isolates focusing on Borrelia burgdorferi acquired from different sources: vectors (ticks), potential vectors (mosquitoes, small mites) and hosts (wild rodents). In the years 1996–2001 a total of 2398 ticks, 72 mites (from wild rodents), 2700 mosquito adults, 1798 mosquito larvae and organ parts (kidney and spleen) of 216 wild rodents were collected from seven localities in the Czech Republic. A total of 31 spirochaete strains were isolated: 13 strains from ticks, 1 strain from mite (Haemogamasus sp.), 15 strains from rodents, 1 strain from mosquito adults and 1 strain from mosquito larva. For the genospecies identification of these isolates PCR, PCR-RFLP was used and their characterization was also performed by SDS-PAGE. By nested PCR method all except one isolated strains were detected as Borrelia burgdorferi s.l. Following PCR-RFLP molecular analysis results, tick isolates were identified as B. garinii and B. afzelii, the strain isolated from the mite was identified as B. afzelii. This is the first isolated strain of B.b.s.l. from a different mite of infraorder Parasitiformes than tick. All of rodent isolates were identified as B. afzelii; mosquito adult isolate was identified as B. afzelii. Larval isolate from mosquito is spirochaete, but does not belong to Borrelia burgdorferi sensu lato group.
In search of mitochondrial markers for resolving the phylogeny of cyclophyllidean tapeworms (Platyhelminthes, Cestoda) — a test study with Davaineidae
Authors: Littlewood D. , Waeschenbach Andrea , Nikolov Pavel
Published: June 2008

The most species rich order of tapeworms is the Cyclophyllidea and prior to wide-scale sampling of these worms for phylogenetics, we wished to develop reliable PCR primers that would capture fragments of mitochondrial (mt) DNA with phylogenetic utility across the order. Nuclear ribosomal RNA gene sequences are well-established and valuable markers for resolving flatworm interrelationships spanning a wide range of taxonomic divergences, but fail to provide resolution amongst recently diverged lineages. Entire mt genomes of selected cyclophyllidean tapeworms are available on GenBank, and we used these to design PCR primers to amplify mtDNA from cox1, rrnL and nad1 for a range of cyclophyllideans (7 davaineids, 1 hymenolepidid and 1 dilepidid) and selected outgroups (Tetrabothrius sp. and Mesocestoides sp.). A combined nuclear and mt gene data set was used to estimate a reference phylogeny and the performance of the individual genes was compared to this. Although nuclear and mt genes each contributed to the structure and stability of the phylogenetic estimate, strongest nodal support was provided by nuclear data amongst the basal lineages and by mt data amongst the most recently diverged lineages. The apparent complementarity afforded by combining nuclear and mt data was compromised by these data partitions providing conflicting signal at poorly supported nodes. Nevertheless, we argue for a combined evidence approach. PCR primers that amplify rrnL were designed and tested successfully against a diversity of cyclophyllideans; rrnL and nad1 appeared to be more informative than the fragment of cox1. The genus Raillietina was not supported by molecular evidence. The new primers will likely provide considerable resolution to estimates of cyclophyllidean interrelationships in future studies.
Dentostomella translucida Schulz et Krepkorgorskaya, 1932 (Nematoda, Heteroxynematidae), a new species for the European nematofauna
Authors: Zaleśny Grzegorz , Hildebrand Joanna , Popiołek Marcin , Okulewicz Anna
Published: June 2008

A nematode Dentostomella translucida was found during parasitological examination of a pet Mongolian gerbil Meriones unguiculatus. Gerbils in the wild are known as hosts of this parasite in Asia, pet gerbils — in the USA and Brazil. Our record is the first in Europe. Complete descriptions of male and female individuals are given.
Cymothoidae and Aegidae (Crustacea, Isopoda) from Algeria
Authors: Ramdane Zouhir , Trilles Jean-Paul
Published: June 2008

Three species of Cymothoidae (Crustacea, Isopoda), Emetha audouini, Ceratothoa collaris and C. steindachneri are here reported from Algeria. The presence of E. audouini and C. collaris is confirmed there and these two species are reported for the first time from Béjaïa, Jijel and Annaba. Ceratothoa steindachneri is new for the Algerian fauna. Ceratothoa oestroides, C. parallela, C. oxyrrhynchaena, Anilocra frontalis, A. physodes and Nerocila bivittata are also recorded. New hosts are identified for C. parallela, C. steindachneri, A. frontalis and A. physodes as well as those of E. audouini. Three species of Aegidae, Aega rosacea, A. deshaysiana and Aega sp. are recorded. The presence of the first is reported for the first time in Algeria and that of the second is confirmed there. For each one of these species, potential preys are identified.
Synthesis and properties of high tilted antiferroelectric esters with partially fluorinated alkoxyalkoxy terminal chains
Authors: Żurowska M. , Dąbrowski R. , Dziaduszek J. , Czupryński K. , Skrzypek K. , Filipowicz M. , Bennis N. , Otón J.
Published: June 2008

Novel chiral esters with partially fluorinated alkoxyalkoxy terminal chains are described. Their phase transition temperatures, enthalpies, and electrooptical properties are reported. A helical pitch in pure compounds and their mixtures based on selective reflection of light is also characterized.
Oriental behaviour of some homologues of 4-n-pentyl-phenylthio-4′-n-alkoxybenzoate doped with dichroic dye
Authors: Bauman D. , Zięba A. , Mykowska E.
Published: June 2008

The long-range orientational order of three members of 4-n-pentylphenylthio-4′-n-alkoxybenzoate $$ (\bar nS5) $$ series doped with a dichroic dye was studied by means of electronic absorption and fluorescence measurements. The order parameters  and  as well as the orientational distribution function were determined on the basis of absorption and emission spectra of linearly polarized light recorded as a function of temperature in the nematic, smectic A, and smectic C phases. An influence of the dye molecular structure on the orientational order of the dye/liquid crystal mixture was observed. Moreover, the dependence of the order parameter values on the length of the alkoxy chain in liquid crystal molecules was found. It was shown that the order parameter , obtained from fluorescence measurements, can be helpful in recognizing the second-order or weakly first-order transitions between various liquid crystalline phases.
Modelling metamaterial transmission lines: a review and recent developments
Authors: Aznar F. , Gil M. , Bonache J. , Martín F.
Published: June 2008

This review paper is devoted to the discussion and comparison of the lumped element equivalent circuit models of the different types of metamaterial transmission lines that have been proposed so far, namely the CL-loaded lines, and those lines based on the resonant type approach. The latter category comprises both artificial lines loaded with split ring resonators (SRRs), or related topologies, and metamaterial transmission lines based on complementary split ring resonators (CSRRs). It will be the main aim of this paper to clearly justify the circuit elements of the models (and link such elements to the line physics and topology), to compare the different lines to the light of these models, and to point out the advantages and drawbacks of the different metamaterial transmission lines. As long as metamaterial transmission lines are exhaustively used for the design of compact microwave and millimeter wave components with improved performance and/or based on new functionalities, and their synthesis is based on the lumped element equivalent circuits, this paper is of actual interest for RF/microwave engineers and in general to those readers involved in metamaterial research and applications.
Morphological and anatomical investigations in Desmodium tortuosum (Sw.) DC. (Fabaceae): A new addition to the Egyptian flora
Authors: Shaheen Abdel Samai Moustafa
Published: June 2008

The morphological, anatomical and micromorphological features of Desmodium tortuosum (Sw.) DC. were investigated to assist in the identification of the species as a new record for Egypt. Specimens collected from different places in the Egyptian Nubia (Nubian Nile Valley) confirmed the presence of D. tortuosum as a naturalized species in the country. In general, the results obtained from the morphological studies were consistent with the previous studies on this species. However, the present investigation into leaf, petiole and stem anatomy and the seed and the leaf patterns under light and scanning electron microscopes, respectively, is the first such study on the species.Keywords: Adaxial bundle, Abaxial bundle, Seed pattern, Micromorphology, Desmodium tortuosumDOI: 10.3329/bjpt.v15i1.908Bangladesh J. Plant Taxon. 15(1): 21-29, 2008 (June)
Brackish water Oscillatoriaceae from North 24-Parganas, West Bengal, India
Authors: Naskar Nurmohammad , Naskar K.R. , Sen C.R.
Published: June 2008

The present communication enumerates 40 taxa of Oscillatoriaceae from the brackish water wetlands of North 24-Parganas district of West Bengal. Out of the reported taxa, 12 are from each of Lyngbya and Oscillatoria, 6 from each of Phormidium and Spirulina, 2 belong to Schizothrix, and Hydrocoleum and Katagnymene are represented by one species each. A close relationship was observed between seasonal water temperature and salinity levels of the wetlands in enhancing algal population.Keywords: Brackish water, species diversity, ecosystem, Oscillatoriaceae, North 24-Parganas, West BengalDOI: 10.3329/bjpt.v15i1.909Bangladesh J. Plant Taxon. 15(1): 31-38, 2008 (June)
Taxonomic study of the genus Ziziphus Mill. (Rhamnaceae) of Bangladesh
Authors: Ara Hosne , Hassan Md. Abul , Khanam Mahbuba
Published: June 2008

A taxonomic account of six species of Ziziphus Mill., viz. Z. funiculosa Buch.-Ham. ex Lowson, Z. glabrata Heyne ex Roth, Z. mauritiana Lam., Z. oenoplia (L.) Mill., Z. rugosa Lam., and Z. xylopyrus (Retz.) Willd. occurring in the flora of Bangladesh has been given. A dichotomous key to the species has been furnished. An updated nomenclature including important synonyms, selected references, description of the taxa along with illustrations, ecological notes, specimens examined and geographical distribution have been provided. Bangla and English names, flowering and fruiting periods, chromosome number and economic importance have also been presented where available.Keywords: Ziziphus; Taxonomy; BangladeshDOI: 10.3329/bjpt.v15i1.917Bangladesh J. Plant Taxon. 15(1): 47-61, 2008 (June)
Marine algae from St. Martins Island, Bangladesh. V. Antithamnionella floccosa (Müller) Whittick (Rhodophyceae), a new record
Authors: Aziz Abdul , Islam A.K.M. Nurul
Published: June 2008

Not available.Keywords: Antithamnionella floccosa, Red alga, Rhodophyceae, Marine algae, BangladeshDOI: 10.3329/bjpt.v15i1.918Bangladesh J. Plant Taxon. 15(1): 63-65, 2008 (June)
Medico-botanical report on the Chakma community of Bangladesh
Authors: Roy Snigdha , Uddin Mohammad Zashim , Hassan Md. Abul , Rahman M. Matiur
Published: June 2008

Not available.DOI: 10.3329/bjpt.v15i1.929Keywords: Chakma tribe; Ethnobotany; BangladeshBangladesh J. Plant Taxon. 15(1): 67-72, 2008 (June)
Validation of the name Paraphlomis hispida C.Y. Wu (Lamiaceae)
Authors: Chunlei Xiang , Hua Peng
Published: June 2008

Not available.Keywords: Paraphlomis hispida; Lamiaceae; Nomenclature; Validation; ChinaDOI: 10.3329/bjpt.v15i1.930Bangladesh J. Plant Taxon. 15(1): 73-74, 2008 (June)
Doubtful occurrence of Solanum nigrum L. in Bangladesh
Authors: Hassan Md. Abul
Published: June 2008

Not available.Keywords: Solanum nigrum, Doubtful occurrence, BangladeshDOI: 10.3329/bjpt.v15i1.931Bangladesh J. Plant Taxon. 15(1): 75-76, 2008 (June)
Trichothecium roseum Link - A new record of hyphomycetous fungus for Bangladesh
Authors: Shamsi Shamim , Sultana Razia
Published: June 2008

Not available.  Keywords: Trichothecium roseum; Hyphomycetes; BangladeshDOI: 10.3329/bjpt.v15i1.932  Bangladesh J. Plant Taxon. 15(1): 77-80, 2008 (June)
Effects of Process Parameters on Tensile Strength of Jute Fiber Reinforced Thermoplastic Composites
Authors: Rashed HMMA , Islam MA , Rizvi FB
Published: June 2008

For Environmental concern on synthetic fibers (such as glass, carbon, ceramic fibers, etc.) natural fibers such as flax, hemp, jute, kenaf, etc. are widely used. In this research work, jute fiber reinforced polypropylene matrix composites have been developed by hot compression molding technique with varying process parameters, such as fiber condition (untreated and alkali treated), fiber sizes (1, 2 and 4 mm) and percentages (5%, 10% and 15% by weight). The developed jute fiber reinforced composites were then characterized by tensile test, optical and scanning electron microscopy. The results show that tensile strength increases with increase in the fiber size and fiber percentage; however, after a certain size and percentage, the tensile strength decreases again. Compared to untreated fiber, no significant change in tensile strength has been observed for treated jute fiber reinforcement. Fractographic observation suggests the fracture behavior to be brittle in nature. Keywords: Natural fiber, Jute fiber, Polypropylene, Composite, Tensile strength.  DOI: 10.3329/jname.v3i1.923 Journal of Naval Architecture and Marine Engineering 3(2006) 1-6
Thermal Radiation Interaction with Unsteady MHD Flow Past a Vertical Porous Plate Immersed in a Porous Medium
Authors: Samad Md Abdus , Mansur-Rahman Mohammad
Published: June 2008

A study of unsteady MHD free convection flow through a porous vertical flat plate immersed in a porous medium in presence of magnetic field with radiation has been analyzed. Introducing a time dependent suction to the plate, a similarity procedure has been adopted by taking a time dependent similarity parameter. In this analysis we consider a Darcy-Forchhemier model and the corresponding momentum and energy equations have been solved numerically, for cooling and heating of the plate by employing Nachtsheim-Swigert iteration technique along with the sixth order Runge-Kutta integration scheme. Non-dimensional velocity and temperature profiles are then presented graphically for different values of the parameter entering into the problem. During the process of numerical computations the skin-friction coefficient (viscous drag) and the rate of heat transfer (Nusselt number), which are of physical interest, are sorted out and presented in the form of tables. Keywords: Thermal radiation, MHD, Unsteady, Suction, Porous medium   DOI: 10.3329/jname.v3i1.924Journal of Naval Architecture and Marine Engineering 3(2006) 7-14
Effect of Microstructure and Notches on the Fracture Toughness of Medium Carbon Steel
Authors: Nath SK , Das Uttam Kr
Published: June 2008

Fracture toughness (K1C) of medium carbon steel (0.5% C) has been determined by round notched tensile specimen. Two notch diameters (5.6mm and 4.2mm) and three notch angles (α) namely 45°, 60° and 75° have been used to observe the effect of notch diameters and notch angle on fracture toughness of the steel. By heat treatment the microstructure of the steel is also varied and its effect on the fracture toughness is also observed. It has been found that fine grained structure improves fracture toughness. Lower notch diameter and higher notch angle show higher value of K1C. Keywords: Fracture toughness, microstructure, notch, heat treatmentDOI: 10.3329/jname.v3i1.925 Journal of Naval Architecture and Marine Engineering 3(2006) 15-22
Effect of Turret Location on the Dynamic Behaviour of an Internal Turret Moored FPSO System
Authors: Kannah T Rajesh , Natarajan R
Published: June 2008

An experimental investigation on the motions and mooring forces of a typical internal turret moored Floating Production Storage and Offloading (FPSO) system under regular sea waves for different loading conditions i.e., 40%DWT, 70%DWT and 100%DWT with different turret locations viz forward, midships and semi- aft positions is reported in this paper. A 1:100 scale model of 140000 DWT turret moored FPSO system was tested in a 2m wide wave flume at a water depth of 1m for the wave frequencies from 0.55Hz to 1.25Hz in steps of 0.04Hz. The motions were measured by rotary type potentiometers and proving ring type load cells were used to measure the mooring forces. From the analysis of the experimental results, it is found that among the three turret locations, the forward turret position is the best suited position for the internal turret moored FPSO system, so as to have favourable and safe working environment. In this turret location, the surge, heave and pitch motions are about 20% to 30% less in comparison with mid ship and semi-aft positions for all loading conditions. Keywords: FPSO system, internal turret, CALM, motions, mooring forces  DOI: 10.3329/jname.v3i1.926Journal of Naval Architecture and Marine Engineering 3(2006) 23-37
Underwater Welding - Present Status and Future Scope
Authors: Majumdar Jyotsna Dutta
Published: June 2008

Welding in offshore and marine application is an area of research and understanding where, many problems are still unsolved. In the present paper, a brief description of the different commercial underwater techniques has been made. The problems in underwater welding have also been discussed in context to the existing welding techniques. Detailed description of a few advanced welding techniques has also been made. Finally, the scope of further research has been recommended. Key words: Under water welding, TIG, MIG, SAW, laser, frictionDOI: 10.3329/jname.v3i1.927Journal of Naval Architecture and Marine Engineering 3(2006) 39-48
Synthesis and Characterization of Some New Tetraaldehyde and Tetraketone Derivatives and X-ray Structure of 1,1'-(4,4'-(2- (1,3-bis(4-Acetylphenoxy)propan-2-ylidene)propane-1,3-diyl) bis(oxy)bis(4,1-phenylene))diethanone
Authors: Er Mustafa , Ustabaş Reşat , Çoruh Ufuk , Sancak Kemal , Vázquez-López Ezequiel
Published: June 2008

Tetraketone and tetraaldehyde derivatives 2a-d were synthesized via the reaction of ethene-1,1,2,2,-tetra-yl-tetramethylene tetrabromide (1) with hydroxyketone and aldehyde derivatives. The molecular structures were identifed by IR, 1H-NMR, 13CNMR and MS analysis. The crystal structure of the title compound 2a, C38H36O8, is reported. Its crystal data are: monoclinic, space group P 2(1)/n with cell dimensions of a= 9.0395(12) Å ,b= 12.6114(17) Å, c = 13.8166(18) Å, β= 95.875(3), V= 1566.8(4) Å3, F.W.= 620.67, ρcalc =1.316 gcm3 for Z=2, μ=0.092 mm-1
Acetaminophen Use During Pregnancy and Children’s Risk of Autism, ADHD, and Intellectual Disability
Authors: Ahlqvist Viktor H. , Sjöqvist Hugo , Dalman Christina , Karlsson Håkan , Stephansson Olof , Johansson Stefan , Magnusson Cecilia , Gardner Renee M. , Lee Brian K.
Published: April 2024

Importance

Several studies suggest that acetaminophen (paracetamol) use during pregnancy may increase risk of neurodevelopmental disorders in children. If true, this would have substantial implications for management of pain and fever during pregnancy.

Objective

To examine the associations of acetaminophen use during pregnancy with children’s risk of autism, attention-deficit/hyperactivity disorder (ADHD), and intellectual disability.

Design, Setting, and Participants

This nationwide cohort study with sibling control analysis included a population-based sample of 2 480 797 children born in 1995 to 2019 in Sweden, with follow-up through December 31, 2021.

Exposure

Use of acetaminophen during pregnancy prospectively recorded from antenatal and prescription records.

Main Outcomes and Measures

Autism, ADHD, and intellectual disability based on International Classification of Diseases, Ninth Revision and International Classification of Diseases, Tenth Revision codes in health registers.

Results

In total, 185 909 children (7.49%) were exposed to acetaminophen during pregnancy. Crude absolute risks at 10 years of age for those not exposed vs those exposed to acetaminophen were 1.33% vs 1.53% for autism, 2.46% vs 2.87% for ADHD, and 0.70% vs 0.82% for intellectual disability. In models without sibling control, ever-use vs no use of acetaminophen during pregnancy was associated with marginally increased risk of autism (hazard ratio [HR], 1.05 [95% CI, 1.02-1.08]; risk difference [RD] at 10 years of age, 0.09% [95% CI, −0.01% to 0.20%]), ADHD (HR, 1.07 [95% CI, 1.05-1.10]; RD, 0.21% [95% CI, 0.08%-0.34%]), and intellectual disability (HR, 1.05 [95% CI, 1.00-1.10]; RD, 0.04% [95% CI, −0.04% to 0.12%]). To address unobserved confounding, matched full sibling pairs were also analyzed. Sibling control analyses found no evidence that acetaminophen use during pregnancy was associated with autism (HR, 0.98 [95% CI, 0.93-1.04]; RD, 0.02% [95% CI, −0.14% to 0.18%]), ADHD (HR, 0.98 [95% CI, 0.94-1.02]; RD, −0.02% [95% CI, −0.21% to 0.15%]), or intellectual disability (HR, 1.01 [95% CI, 0.92-1.10]; RD, 0% [95% CI, −0.10% to 0.13%]). Similarly, there was no evidence of a dose-response pattern in sibling control analyses. For example, for autism, compared with no use of acetaminophen, persons with low (<25th percentile), medium (25th-75th percentile), and high (>75th percentile) mean daily acetaminophen use had HRs of 0.85, 0.96, and 0.88, respectively.

Conclusions and Relevance

Acetaminophen use during pregnancy was not associated with children’s risk of autism, ADHD, or intellectual disability in sibling control analysis. This suggests that associations observed in other models may have been attributable to familial confounding.
Firearm Ownership and Support for Political Violence in the United States
Authors: Wintemute Garen J. , Crawford Andrew , Robinson Sonia L. , Tomsich Elizabeth A. , Reeping Paul M. , Schleimer Julia P. , Pear Veronica A.
Published: April 2024

Importance

Little is known about support for and willingness to engage in political violence in the United States. Such violence would likely involve firearms.

Objective

To evaluate whether firearm owners’ and nonowners’ support for political violence differs and whether support among owners varies by type of firearms owned, recency of purchase, and frequency of carrying a loaded firearm in public.

Design, Setting, and Participants

This cross-sectional nationally representative survey study was conducted from May 13 to June 2, 2022, among US adult members of the Ipsos KnowledgePanel, including an oversample of firearm owners.

Exposure

Firearm ownership vs nonownership.

Main Outcomes and Measures

Main outcomes concern (1) support for political violence, in general and to advance specific political objectives; (2) personal willingness to engage in political violence, by severity of violence and target population; and (3) perceived likelihood of firearm use in political violence. Outcomes are expressed as weighted proportions and adjusted prevalence differences, with P values adjusted for the false-discovery rate and reported as q values.

Results

The analytic sample comprised 12 851 respondents: 5820 (45.3%) firearm owners, 6132 (47.7%) nonowners without firearms at home, and 899 (7.0%) nonowners with firearms at home. After weighting, 51.0% (95% CI, 49.9%-52.1%) were female, 8.5% (95% CI, 7.5%-9.5%) Hispanic, 9.1% (95% CI, 8.1%-10.2%) non-Hispanic Black, and 62.6% (95% CI, 61.5%-63.8%) non-Hispanic White; the mean (SD) age was 48.5 (18.0) years. Owners were more likely than nonowners without firearms at home to consider violence usually or always justified to advance at least 1 of 17 specific political objectives (owners: 38.8%; 95% CI, 37.3%-40.4%; nonowners: 29.8%; 95% CI, 28.5%-31.2%; adjusted difference, 6.5 percentage points; 95% CI, 4.5-9.3 percentage points; q < .001) but were not more willing to engage in political violence. Recent purchasers, owners who always or nearly always carry loaded firearms in public, and to a lesser extent, owners of assault-type rifles were more supportive of and willing to engage in political violence than other subgroups of firearm owners.

Conclusions and Relevance

In this study of support for political violence in the United States, differences between firearm owners and nonowners without firearms at home were small to moderate when present. Differences were greater among subsets of owners than between owners and nonowners. These findings can guide risk-based prevention efforts.
Top Factors in Nurses Ending Health Care Employment Between 2018 and 2021
Authors: Muir K. Jane , Porat-Dahlerbruch Joshua , Nikpour Jacqueline , Leep-Lazar Kathryn , Lasater Karen B.
Published: April 2024

Importance

The increase in new registered nurses is expected to outpace retirements, yet health care systems continue to struggle with recruiting and retaining nurses.

Objective

To examine the top contributing factors to nurses ending health care employment between 2018 and 2021 in New York and Illinois.

Design, Setting, and Participants

This cross-sectional study analyzed survey data (RN4CAST-NY/IL) from registered nurses in New York and Illinois from April 13 to June 22, 2021. Differences in contributing factors to ending health care employment are described by nurses’ age, employment status, and prior setting of employment and through exemplar nurse quotes.

Main Outcomes and Measures

Nurses were asked to select all that apply from a list of contributing factors for ending health care employment, and the percentage of nurse respondents per contributing factor were reported.

Results

A total of 7887 nurses (mean [SD] age, 60.1 [12.9] years; 7372 [93%] female) who recently ended health care employment after a mean (SD) of 30.8 (15.1) years of experience were included in the study. Although planned retirement was the leading factor (3047 [39%]), nurses also cited burnout or emotional exhaustion (2039 [26%]), insufficient staffing (1687 [21%]), and family obligations (1456 [18%]) as other top contributing factors. Among retired nurses, 2022 (41%) ended health care employment for reasons other than planned retirement, including burnout or emotional exhaustion (1099 [22%]) and insufficient staffing (888 [18%]). The age distribution of nurses not employed in health care was similar to that of nurses currently employed in health care, suggesting that a demographically similar, already existing supply of nurses could be attracted back into health care employment.

Conclusions and Relevance

In this cross-sectional study, nurses primarily ended health care employment due to systemic features of their employer. Reducing and preventing burnout, improving nurse staffing levels, and supporting nurses’ work-life balance (eg, childcare needs, weekday schedules, and shorter shift lengths) are within the scope of employers and may improve nurse retention.
A Mn2+‐Assisted Nanofiber‐Hydrogel Adjuvant for Simultaneous Enhancement of Humoral and Cellular Immune Responses
Authors: Jia Haixue , Lin Jia , Wang Dianyu , Lv Xue , Wang Qian , Wang Zhongyan , Liu Jinjian , Yang Lijun , Liu Jianfeng
Published: April 2024

Limited ability to elicit cellular immune responses has restricted the effectiveness of conventional adjuvants in the context of cancers. Recent advancements in innate immune activation mechanism investigations have paved the way for the implementation of a “bottom‐up” approach in the development of novel adjuvants. Herein, a simple hydrogel adjuvant with a uniformly organized nanoscale microstructure, termed MnPgel is devised, by employing self‐assembling peptides incorporated with manganese ions (Mn2+). MnPgel exhibits Mn2+ sustained‐release properties in vivo and effectively promotes germinal center formation, thereby facilitating the generation of antibodies at levels comparable to conventional aluminum‐based adjuvants. Moreover, MnPgel transcends the scope of humoral immunity, demonstrating the ability to robustly trigger cellular immune responses and positioning it as a promising candidate for cancer prevention and treatments. In conclusion, the work has introduced a well‐defined hydrogel adjuvant as a proof‐of‐concept, simplifying vaccine adjuvant design and opening up new avenues for “on‐demand” immunomodulation strategies.
Orienting Electron Fillings in d Orbitals of Cobalt Single Atoms for Effective Zinc–Air Battery at a Subzero Temperature
Authors: Yan Yan , Wen Bihan , Liu Mingkai , Lei Hao , Yang Jifeng , He Siyuan , Qu Zehua , Xia Wei , Li Hongliang , Zeng Jie
Published: April 2024

The missions in extreme environments such as the moon, the Arctic/Antarctic, and the plateau require the operation of batteries at low temperatures even below the freezing point of water. Herein, it is reported that compressively stressed Co single atoms exhibit enhanced oxygen reduction reaction (ORR) activity and enable the effective operation of zinc–air battery at a subzero temperature. The compressive strain is generated by depositing Co single atoms on highly arced carbon layers with ultra‐small curvature radii ≈2 nm. The locally compressive strain on Co single atoms redistributes the electron fillings in d orbitals with different spatial orientations, thereby strengthening the adsorption of active intermediates and enhancing the activity toward ORR. As expected, compressively stressed Co single atoms outperform Co single atoms on a flat support without strain in terms of kinetic current density (31.09 mA cm−2 vs 0.35 mA cm−2) at 0.85 V during ORR. The integration of the catalyst into a Zn–air battery generates a superior power density of 54.8 mW cm−2 than the commercial Pt/C counterpart (24.1 mW cm−2) at −40 °C.
Reprogrammable Multi‐Responsiveness of Regenerated Silk for Versatile Soft Actuators
Authors: Xiao Jianliang , Liu Haitao , Wang Shan , Ma Shuqi , Zhang Lei , Qi Yizhou
Published: April 2024

Developing stimulus‐responsive materials (SRMs) with reversible, large, and reprogrammable multi‐responsiveness is crucial for soft actuators and intelligent devices, which remains challenging. In this study, regenerated silk fibroin with hierarchical structure is utilized to specially design a reprogrammable multi‐stimuli‐responsive protein film and versatile soft actuators. The freestanding fibroin films exhibit notable thermal contraction (−1383 ppm K−1) and humidity‐responsiveness that can be repeatedly regulated by easy post‐treatment with Ca2+ as desired. The actuating and regulating mechanisms involve reversible conformational change that is magnified into macroscopic deformations by hierarchical structure, and the roles of material structure and ambient conditions in determining actuating performances are analyzed based on thermodynamics. Driven by humidity gradient, the fibroin film demonstrates spontaneous flipping locomotion, self‐oscillation with tunable frequencies, bio‐butterfly wing flapping, and transformation from 2D to 3D structure. Moreover, reprogrammable deformations at specific regions are achieved in multi‐stimuli‐driven PET/fibroin film actuators owing to the straightforward Ca2+‐content‐based tunability of the responsiveness. The fibroin‐based actuators can be used as artificial muscles to drive the high‐frequency wing‐flapping of a bio‐dragonfly and soft gripper to grasp, lift, and transfer objects. The simple yet effective strategy presented herein provides valuable inspiration for designing advanced SRMs and soft actuators with reprogrammable multi‐responsiveness.
Superspreading of Polyelectrolyte Complex Solution for Constructing Hydrogel Coatings on Diverse Substrates
Authors: Wei Congying , Zhao Chuangqi , Ru Yunfei , Sun Yingzhi , Zhao Tianyi , Qi Shuanhu , Zhou Jiajia , Liu Mingjie
Published: April 2024

Injectable hydrogels have emerged as versatile materials with potential applications in various fields, including biomedicine, lubrication, adhesion, surface coatings, and tissue engineering. However, the critical aspect of spreading and wetting on various substrates, which is essential for obtaining significant interfacial properties, has not been adequately addressed. This work presents an approach to prepare hydrogel coatings on kinds of substrates through the superspreading of polyelectrolyte complex solution during its liquid‐liquid phase inversion process. Due to the low interfacial tension, the solution spreads and wets various surfaces underwater driven by osmotic pressure, improving the contact area and interface integration. Combined with the simultaneous sol‐gel transition through electrostatic interaction, it forms a stable and homogeneous hydrogel coating. The hydrogel coating possesses control thickness (4–8 µm), improved hydrophilicity (CA decrease from 102° to 10°), interfacial toughness (increase from 70 to 455 J m−2), and lubrication performance (coefficients of friction decrease from 0.712 to 0.112). The work provides an excellent opportunity to investigate the spreadability and wettability in a water/water/solid three‐phase system and develop functional hydrogel coatings for various applications.
New Understanding and Improvement in Sintering Behavior of Cerium‐Rich Perovskite‐Type Protonic Electrolytes
Authors: Wang Zehua , Luo Zhixin , Xu Hengyue , Zhu Tianjiu , Guan Daqin , Lin Zezhou , Chan Ting‐Shan , Huang Yu‐Cheng , Hu Zhiwei , Jiang San Ping , Shao Zongping
Published: April 2024

Protonic ceramic cells show great promises for electrochemical energy conversion and storage, while one of the key challenges lies in fabricating dense electrolytes. Generally, the poor sinterability of most protonic ceramic electrolytes, such as BaZr0.1Ce0.7Y0.1Yb0.1O3‐δ, is attributed to the Ba evaporation at high temperatures. In a systematic and comparative study of BaCeO3 and BaZrO3, the results demonstrated that Ba tends to segregate to grain boundaries rather than evaporate. Additionally, thermal reduction of Ce4+ to Ce3+ promotes the displacement of Ce to the Ba‐site or the exsolution of CeO2 phase, leading to an abnormal lattice shrinkage of perovskite phase and hindering the electrolyte densification. Contrary to previous beliefs that Ba deficiency inhibits the electrolyte sintering, the findings indicate that it surprisingly promotes the sintering of BaZrO3 perovskites, while excess Ba negatively affects its sintering behavior due to the accumulation of Ba species at grain boundaries. As to BaCeO3, excess Ba improves electrolyte sintering by suppressing the Ce exsolution at high temperatures. Meanwhile, Co‐doping Zr and Ce in the B‐site of protonic perovskite can optimize the sintering characteristic. These findings offer new insights into sintering of protonic perovskites and provide guidance for the development of new protonic devices.
“Heterodimensional Structure” Integrated Defect and Interface Engineering for Efficiently EMI Shielding and Electrochemical Response
Authors: Liu Ting‐Ting , Wang Yu‐Chang , Wang Yu‐Ze , Cao Mao‐Sheng
Published: April 2024

Two colossal global challenges remain energy scarcity and environmental pollution, having evolved into problems that human society cannot ignore. Therefore, developing a material with efficient electromagnetic (EM) interference shielding and electrocatalytic properties has become imperative in promoting sustainable development and establishing environmental protection systems. Herein, a heterodimensional structure is prepared by assembling 3D spirally grown VS2 with 2D FeCo‐LDH, which precisely manipulates macroscopic EM and electrochemical characteristics through defect and interface engineering. The results show that the heterodimensional structure presents an efficient shielding effectiveness of 30.2 dB at 18 GHz. Heterodimensional structure exhibits a low overpotential of 279 mV, achieving a current density of 10 mA cm−2 and a desirable stability. In addition, based on the unique electrochemical properties and EM response characteristics of the material, a special protective helmet is innovated. The helmet incorporating an autonomous oxygen supply, advanced pressure surveillance, and dynamic stealth supports a more exhaustive safeguard for missions amidst noxious gases, and situations necessitating clandestine operations. This research provides a new idea for the development of multifunctional EM active materials, showing great application prospects in the fields of aerospace engineering, energy, and EM security protection.
Injectable, Electroconductive, Free Radical Scavenging Silk Fibroin/Black Phosphorus/Glycyrrhizic Acid Nanocomposite Hydrogel for Enhancing Spinal Cord Repair
Authors: Zhang Beichen , Wang Wanshun , Gao Peng , Li Xiang , Chen Lingling , Lin Zefeng , Chen Hu , Liang Wenhao , Kong Zhiyuan , Lin Dingkun , Wu Xiaona , Zhang Tao
Published: April 2024

Spinal cord injury (SCI) often leads to a severe permanent disability. A poor inflammatory microenvironment and nerve electric signal conduction block are the main reasons for difficulty in spinal cord nerve regeneration. In this study, black phosphorus (BP) and glycyrrhizic acid (GA) are integrated into methacrylate‐modified silk fibroin (SF) to construct a bifunctional injectable hydrogel (SF/BP/GA) with appropriate conductivity and the ability to inhibit inflammation to promote neuronal regeneration after SCI. This work discovers that the SF/BP/GA hydrogel can reduce the oxidative damage mediated by oxygen free radicals, promote the polarization of macrophages toward the anti‐inflammatory M2 phenotype, reduce the expression of inflammatory factors, and improve the inflammatory microenvironment. Moreover, it induces neural stem cell (NSC) differentiation and neurosphere formation, restores signal conduction at the SCI site in vivo, and ameliorates motor function in mice with spinal cord hemisection, revealing a significant neural repair effect. An injectable, electroconductive, free‐radical‐scavenging hydrogel is a promising therapeutic strategy for SCI repair.
Noble‐Metal‐Free High‐Entropy Alloy Nanoparticles for Efficient Solar‐Driven Photocatalytic CO2 Reduction
Authors: Huang Haowei , Zhao Jiwu , Guo Hele , Weng Bo , Zhang Hongwen , Saha Rafikul Ali , Zhang Menglong , Lai Feili , Zhou Yufan , Juan Rubio‐Zuazo , Chen Peng‐Cheng , Wang Sibo , Steele Julian A. , Zhong Fulan , Liu Tianxi , Hofkens Johan , Zheng Yu‐Ming , Long Jinlin , Roeffaers Maarten B. J.
Published: April 2024

Metal nanoparticle (NP) cocatalysts are widely investigated for their ability to enhance the performance of photocatalytic materials; however, their practical application is often limited by the inherent instability under light irradiation. This challenge has catalyzed interest in exploring high‐entropy alloys (HEAs), which, with their increased entropy and lower Gibbs free energy, provide superior stability. In this study, 3.5 nm‐sized noble‐metal‐free NPs composed of a FeCoNiCuMn HEA are successfully synthesized. With theoretic calculation and experiments, the electronic structure of HEA in augmenting the catalytic CO2 reduction has been uncovered, including the individual roles of each element and the collective synergistic effects. Then, their photocatalytic CO2 reduction capabilities are investigated when immobilized on TiO2. HEA NPs significantly enhance the CO2 photoreduction, achieving a 23‐fold increase over pristine TiO2, with CO and CH4 production rates of 235.2 and 19.9 µmol g−1 h−1, respectively. Meanwhile, HEA NPs show excellent stability under simulated solar irradiation, as well high‐energy X‐ray irradiation. This research emphasizes the promising role of HEA NPs, composed of earth‐abundant elements, in revolutionizing the field of photocatalysis.