bluuebunny/crossref_metadata_2025 huggingface dataset:
β-catenin inhibition disrupts the homeostasis of osteogenic/adipogenic differentiation leading to the development of glucocorticoid-induced osteonecrosis of femoral head
Authors: Xia Chenjie , Xu Huihui , Fang Liang , Chen Jiali , Yuan Wenhua , Fu Danqing , Wang Xucheng , He Bangjian , Xiao Luwei , Wu Chengliang , Tong Peijian , Chen Di , Wang Pinger , Jin Hongting
Published: January 2024

Glucocorticoid-induced osteonecrosis of the femoral head (GONFH) is a common refractory joint disease characterized by bone damage and the collapse of femoral head structure. However, the exact pathological mechanisms of GONFH remain unknown. Here, we observed abnormal osteogenesis and adipogenesis associated with decreased β-catenin in the necrotic femoral head of GONFH patients. In vivo and in vitro studies further revealed that glucocorticoid exposure disrupted osteogenic/adipogenic differentiation of bone marrow mesenchymal cells (BMSCs) by inhibiting β-catenin signaling in glucocorticoid-induced GONFH rats. Col2
+
lineage largely contributes to BMSCs, and was found an osteogenic commitment in the femoral head through 9 months of lineage trace. Specific deletion of
β-catenin
in Col2
+
cells shifted their commitment from osteoblasts to adipocytes, leading to a full spectrum of disease phenotype of GONFH in adult mice. Overall, we uncover that β-catenin inhibition disrupting the homeostasis of osteogenic/adipogenic differentiation contributes to the development of GONFH, and identify an ideal genetic modified mouse model of GONFH.
FBXO24 deletion causes abnormal accumulation of membraneless electron-dense granules in sperm flagella and male infertility
Authors: Kaneda Yuki , Miyata Haruhiko , Xu Zoulan , Shimada Keisuke , Kamoshita Maki , Nakagawa Tatsuya , Emori Chihiro , Ikawa Masahito
Published: January 2024

Ribonucleoprotein (RNP) granules are membraneless electron-dense structures rich in RNAs and proteins, and involved in various cellular processes. Two RNP granules in male germ cells, intermitochondrial cement and the chromatoid body (CB), are associated with PIWI-interacting RNAs (piRNAs) and are required for transposon silencing and spermatogenesis. Other RNP granules in male germ cells, the reticulated body and CB remnants, are also essential for spermiogenesis. In this study, we disrupted FBXO24, a testis-enriched F-box protein, in mice and found numerous membraneless electron-dense granules accumulated in sperm flagella. Fbxo24 knockout (KO) mice exhibited malformed flagellar structures, impaired sperm motility, and male infertility, likely due to the accumulation of abnormal granules. The amount and localization of known RNP granule-related proteins were not disrupted in Fbxo24 KO mice, suggesting that the accumulated granules were distinct from known RNP granules. Further studies revealed that RNAs and two importins, IPO5 and KPNB1, abnormally accumulated in Fbxo24 KO spermatozoa and that FBXO24 could ubiquitinate IPO5. In addition, IPO5 and KPNB1 were recruited to stress granules, RNP complexes, when cells were treated with oxidative stress or a proteasome inhibitor. These results suggest that FBXO24 is involved in the degradation of IPO5, disruption of which may lead to the accumulation of abnormal RNP granules in sperm flagella.
Hyperglycemia-induced cathepsin L maturation: Implications for diabetic comorbidities and COVID-19 susceptibility
Authors: He Qiong , Zhao Miao-Miao , Li Ming-Jia , Li Xiao-Ya , Jin Jian-Min , Feng Ying-Mei , Zhang Li , Huang Wei-Jin , Yang Fang-Yuan , Yang Jin-Kui
Published: January 2024

Diabetes is the second most frequent chronic comorbidity for COVID-19 mortality, yet the underlying mechanism remains unclear. Previous studies suggest that Cathepsin L (CTSL) is implicated in diabetic complications such as nephropathy and retinopathy. Our previous research identified CTSL as a critical protease that promotes SARS-CoV-2 infection and a potential drug target. Here, we show that individuals with diabetes have elevated blood CTSL levels, which facilitates SARS-CoV-2 infection. Chronic hyperglycemia, as indicated by HbA1c levels, is positively correlated with CTSL concentration and activity in diabetic patients. Acute hyperglycemia induced by a hyperglycemic clamp in healthy individuals increases CTSL activity.
In vitro,
high glucose, but not high insulin, promotes SARS-CoV-2 infection in wild-type (WT) cells, while
CTSL
knockout (KO) cells show reduced susceptibility to high glucose-promoted effects. Using lung tissue samples from diabetic and non-diabetic patients, as well as db/db diabetic and control mice, our findings demonstrate that diabetic conditions increase CTSL activity in both humans and mice. Mechanistically, high glucose levels promote CTSL maturation and CTSL translocation from the endoplasmic reticulum (ER) to the lysosome via the ER-Golgi-lysosome axis. This study emphasizes the significance of hyperglycemia-induced cathepsin L maturation in the development of diabetic comorbidities and complications.
PURA syndrome-causing mutations impair PUR-domain integrity and affect P-body association
Authors: Proske Marcel , Janowski Robert , Bacher Sabrina , Kang Hyun-Seo , Monecke Thomas , Koehler Tony , Hutten Saskia , Tretter Jana , Crois Anna , Molitor Lena , Varela-Rial Alejandro , Fino Roberto , Donati Elisa , De Fabritiis Gianni , Dormann Dorothee , Sattler Michael , Niessing Dierk
Published: January 2024

Mutations in the human PURA gene cause the neurodevelopmental PURA syndrome. In contrast to several other monogenetic disorders, almost all reported mutations in this nucleic acid-binding protein result in the full disease penetrance. In this study, we observed that patient mutations across PURA impair its previously reported co-localization with processing bodies. These mutations either destroyed the folding integrity, RNA binding, or dimerization of PURA. We also solved the crystal structures of the N- and C-terminal PUR domains of human PURA and combined them with molecular dynamics simulations and nuclear magnetic resonance measurements. The observed unusually high dynamics and structural promiscuity of PURA indicated that this protein is particularly susceptible to mutations impairing its structural integrity. It offers an explanation why even conservative mutations across PURA result in the full penetrance of symptoms in patients with PURA syndrome.
An arms race under RIG-I loss: 5’ppp-RNA and its alternative recognition receptor MDA5
Authors: Geng Shang , Lv Xing , Zheng Weiwei , Xu Tianjun
Published: January 2024

The incessant arms race between viruses and hosts has led to numerous evolutionary innovations that shape the evolution of life. During this process, the interactions between viral receptors and viruses have garnered significant interest since viral receptors are cell surface proteins exploited by viruses to initiate infection. To further understand the interaction between viruses and receptors, our study sheds light on the arms race between the MDA5 receptor and 5’ppp-RNA in vertebrates. Firstly, the frequent and independent loss events of RIG-I in vertebrates prompted us to search for alternative immune substitutes, with homology-dependent genetic compensation response (HDGCR) being the main pathway. Our further analysis suggested that MDA5, the homolog of RIG-I, can replace RIG-I in recognizing 5’ppp-RNA and bind STING for signal transduction, which may lead to redundancy of RIG-I and loss from the species genome during evolution. Secondly, as an adversarial strategy, 5’ppp-RNA SCRV can utilize the m
6
A methylation mechanism to degrade MDA5 and weaken its antiviral immune ability, thus promoting its own replication and immune evasion. In summary, our study has revealed the molecular mechanisms underlying the interaction and coevolution between vertebrate and virus, which providing valuable insights into the ecological and evolutionary factors that contribute to the diversity of the immune system.
Endividamento: um estudo do pré e pós da crise empresarial brasileira na pandemia do COVID-19
Authors: Dias Marlysandra Machado , De Oliveira Michele Ribeiro , Araújo Maria Beatriz de Sousa , Gomes Arone Maria , Carvalho Aline Kárem Santos , Viana Marcelo Melo , De Lemos Jane Gabriela Soares , De Morais Silvia Piva Rosal , Toscano Thais Sales Barreto , Veras Sabrina Maria Parente , De Moura Ana Gabriella Moreira , Silva Poena Livia Bonfim , Araujo Marcus Vinícius Freire Uchôa
Published: January 2024

A economia brasileira, desde antes da pandemia, vinha passando por um processo de desaceleração, enfrentando dificuldades para o seu crescimento. Com o cenário pandêmico da Covid-19, as empresas sofreram ainda mais com esse momento de crise, devido a paralisação das atividades presenciais. Dessa forma, para a obtenção dos resultados da pesquisa, teve-se como objetivo geral do presente estudo, analisar e comparar o estado econômico das empresas brasileiras, listadas na B3. Neste estudo, foram aplicados sete indicadores financeiros, os quais são ferramentas utilizadas pelos gestores na compreensão dos números das suas empresas. Quanto à metodologia, decorreu de uma pesquisa descritiva e quantitativa utilizado o teste T de Student e o teste F de Levene. A partir das informações extraídas dos testes estatísticos há indícios de que houve um aumento significativo, do ponto de vista estatístico, do endividamento geral da empresa contribuindo para o aumento do risco dos negócios.
Abordagem centrada na pessoa e suas possíveis articulações na prevenção ao uso de drogas em contextos militares
Authors: De Souza Junior Sidnei Nogueira , Cruz Annebelle Pena Lima Magalhães , Cruz Luiz Marcelo Magalhães
Published: January 2024

O artigo tem como objetivo abordar a temática da dependência química no contexto militar através de pesquisas sobre bibliografias publicadas, diretas ou indiretas, relacionadas a Força Terrestre e a partir da Abordagem Centrada na Pessoa. Além buscar referências acerca da importância da Abordagem Centrada na Pessoa como possibilidade de articulaçoa frente a perspectiva psioeducativa e como forma de intervenção, que vá além do modelo de doença, considerando aspectos morais, ético-legais, psicológicos, psicossociais e socioculturais. Justificando-se como pesquisa, pois a dependência química é descrita como um fenômeno multifatorial ligado a problemas sociais e de saúde pública, representando um desafio para os serviços de cuidado devido ao preconceito e discriminação, carecendo sempre de constantes discusões. A metodologia foi realizada por meio de pesquisa qualitativa, exploratória, bibliográfica e documental. Utilizando-se ainda, de A pesquisa por meio de descritores do Google Acadêmico. Concluindo-se que ainda há a necessidade de maiores estudos sobre prevenção à dependência química, visando estratégias de intervenção eficazes para militares e seus familiares. Apontando ainda, o instrumento "ASSIST" para triagem do uso de substâncias psicoativas e propõe a subdivisão do tema em duas vertentes: acolhimento individual e abordagem centrada nas particularidades da profissão militar. Além disso, sugere lentes que se direcionem para aumentar os trabalhos acerca da prevenção e do acolhimento acerca do problema.
Stock Assessment and Virtual Population Analysis of Carassius auratus (Linnaeus, 1758) in the Al-Diwaniya River, Middle of Iraq
Authors: Mohamed Abdul-Razak M.
Published: January 2024

A total of 1128 individuals of C. auratus were collected from the Diwaniyah River, Iraq. Samples were collected between November 2016 and October 2017 using different fishing gears aiming to assess the stock assessment and virtual population analysis. Fish length ranged from 8.0 to 33.0 cm, with a length-weight relationship exhibiting positive allometric growth. Asymptotic length (L∞) was estimated at 33.0 cm, the growth coefficient (K) was 0.16, and the growth performance index (Ǿ) was 2.241. The values of total (Z), natural (M) and fishing (F) mortality rates were 0.89, 0.47, and 0.42, respectively. The exploitation rate (E) was 0.48. Length with a 50% probability of capture (LC50) was estimated at 18.7 cm and was higher than the length at first maturity (Lm50). The recruitment consisted of one seasonal pulse from April to July. The exploitation rate (E) was below the biological target reference points (E0.1 and Emax), indicating the stock was under exploitation state. The result of the virtual population analysis revealed that most of the fishing mortality happened in mid-lengths (18-26 cm) with a maximum rate at a length of 25 cm. Natural losses were highest among individuals within the length range of 8.0 to 15 cm and then decreased gradually to the length group of 30. For management purposes, this study suggests that more yields can be obtained by increasing the fishing activities on this invasive species, such as increasing the number of fishing boats and decreasing the mesh size to decline its abundance in the long term.
Sexual Invigorating Potentials of a Combined Extract of Sabicea calycina and Carpolobia lutea on Male Wistar Rats in Crude Oil Challenged Environment
Authors: Kpomah E. D.  , Osioma E.  , Agoro E. S.
Published: January 2024

The effect of 50, 100 and 200 mg/kg of combined ethanol extract of S. calycina and C. lutea were investigated on mating behavioural parameters and sex/reproductive hormone boosting potentials in both non-bonny light crude oil (NBLCO) and bonny light crude oil (BLCO) environmentally challenged rats. Forty sexually experienced rats weighing 120-135g were arbitrarily allocated into two groups of twenty rats as NBLCO and BLCO respectively, each group were further subdivided into four groups of five rats and administered orally with 50 mL distilled water (control) and the extract of S. calycina and C. lutea at doses of 50, 100 and 200 mg/kg body weight. After 21 days of treatment protocols, the animals were observed for both precopulatory and copulatory activities, sex hormone was also evaluated. The copulatory activities monitored showed that mount latency, intromission latency and post ejaculatory intervals were significantly decreased by the 100 and 200 mg/kg of the extract in both the NBLCO and BLCO-challenged rats (P < 0.05). All doses significantly increased (P < 0.05) the mount frequency, intromission frequency, and ejaculatory frequency in the NBLCO groups while only the 100 and 200 mg/kg body weight was able. Copulatory efficiency was significantly increased (P < 0.05) by all doses in a dose-related manner in the NBLCO groups while only the 200 mg/kg dose level was able to significantly increase (P < 0.05) the copulatory efficiency in the BLCO groups. The hormonal assay showed that all doses produced a significant increase (P < 0.05) in testosterone, luteinizing hormone, follicle-stimulating hormone, and progesterone, with a concomitantly significant decrease (P < 0.05) in prolactin in the NBLCO groups, however, only the 100 and 200 mg/kg was able to able to achieve significant change (P < 0.05) in these hormonal levels in the BLCO groups. Findings from this study showed that the extract has aphrodisiac potentials and also the ability to restore hyposexual activity in rats challenged with crude oil.
Study on Sexual Behaviour Parameters of Marwari Stallions during Breeding Season
Authors: Yadav Vishal , Dholpuria Sandeep , Talluri Thirumala Rao , Joshi Abhishek , Khandelwal Shivali , Kumar Ashok
Published: January 2024

The ejaculation and mounting times of a stallion, as well as the amount of time it takes for the stallion to respond to an oestrus mare, are all elements that might affect the libido of the horse. In order to gain an understanding of how tropical horses adapt to potentially difficult climatic circumstances in terms of their sexual performance, it is necessary to study their reproductive behaviour. The present investigation was carried out on six healthy Marwari stallions (aged between 50 to 140 months) to evaluate and to analyse their sexual behaviour during the breeding season in the arid region. The study was carried out for a period of three weeks and sexual behaviour parameters were recorded at the time of semen collection. Parameters observed and analysed in the present study include erection time, reaction time, ejaculation time, number of mounts and number of thrusts. Erection time, reaction time and ejaculation time of stallions was 19.02±1.18 sec, 29.11±1.37 sec, 26.86±0.95 sec, respectively. The number of mounts and number of thrusts of stallions was 1.39±0.09 and 10.00±0.17 respectively. The above study describes the normal sexual behaviour parameters of Marwari stallions in the arid region and analysed that non-significant (P>0.05) difference exists among the horses for various sexual behaviour parameters.
Distribution, Diversity and Biochemical Analysis of Endophytic Fungi Associated with Chromolaena odorata
Authors: Nongthombam Kistu Singh , Mutum Shyamkesho Singh , Pandey Radha Raman
Published: January 2024

Chromolaena odorata is a medicinal plant that possesses several properties, including antibacterial, antifungal, anti-inflammatory, anticancer, antioxidant, etc., and has been used in traditional medicine in various parts of the world. Medicinal plants are associated with endophytic fungi that have potential biological activities as well as protect the plant from biotic and abiotic agents. In this study, endophytic fungi were isolated from the leaves, stems, roots, and inflorescence of C. odorata and identified morphologically. Nineteen sporulating endophytic fungi belonging to 9 genera, 8 families and 4 classes, and three sterile forms were obtained. The isolation data recorded were used to calculate Isolation rate, Colonization frequency, Infection rate and Relative occurrence of different groups of fungi. The highest Isolation rate was found in the stem part (34.75%); the highest overall Colonization frequency (%) was shown by Chaetomium globosum (8.51%); the maximum Infection rate was found in root segments (77.86%); and the maximum isolate belongs to Sordariomycetes, showing 43.50%. Simpson’s dominance index, Simpson’s diversity index, Species richness, Shannon-Wiener index and Evenness (E) index were calculated to reveal diversity indices. The maximum diversity was recorded in the leaf part (0.99), and the maximum number of endophytic fungal species was observed in stem segments. The production of biochemicals was analyzed qualitatively, and it was observed that all the isolates produce flavonoids and phenols. This indicates that endophytic fungi are a storehouse of natural compounds and can be applied in agriculture, medicine, and pharmaceutical industries.
A memory and decision model for eyewitness identification
Authors: Clark Steven E.
Published: September 2003

A computer simulation model of eyewitness identification called WITNESS is proposed and fit to data from three experiments: Juslin et al. (1996), Tunnicliff and Clark (2000), and Wells et al. (1993). These three experiments directly compared two procedures for selecting foils for lineups: by selecting foils that either match the photograph of the suspect or match the description of the perpetrator given by the witness. The model assumes that (a) memory of a perpetrator is incomplete and error‐prone, (b) lineup alternatives are matched to this error‐prone memory trace, (c) identification decisions are based on a combination of relative and absolute match information, and (d) lineup rejections are based solely on absolute match information. The model provided good fits to data, although with important deviations between the model and data. Implications and limitations of the model, as well as future development of the model, are discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Exploring the time prediction process: the effects of task experience and complexity on prediction accuracy
Authors: Thomas Kevin E. , Newstead Stephen E. , Handley Simon J.
Published: September 2003

Whilst considerable research shows that people tend to underestimate their task completion times, there is little research concerning factors that mediate the time prediction process. In Experiments 1 to 3 a simple, well‐structured task, the 3‐disk Tower of Hanoi, showed no evidence of underestimation; in fact, participants consistently overestimated the duration of this task. However, predictions were more accurate among participants who acquired some task experience beforehand. Task complexity was also found to be an important factor since the more cognitively complex 4‐ and 5‐disk versions produced less biased predictions. Using a cognitively undemanding disk movement task, we found a general temporal overestimation in Experiment 4, thus suggesting that task duration might be responsible for the general lack of underestimation in the present studies. These results have implications for the planning of tasks in everyday life, and also suggest conditions under which time prediction accuracy can be improved. Copyright © 2003 John Wiley & Sons, Ltd.
Splintered memories or vivid landmarks? Qualities and organization of traumatic memories with and without PTSD
Authors: Berntsen Dorthe , Willert Morten , Rubin David C.
Published: September 2003

One hundred and eighty‐one students answered a standardized questionnaire on Post‐Traumatic Stress Disorder (PTSD): 25 reported trauma(s) and indicated a pattern of after‐effects that matched a PTSD symptom profile, whereas 88 indicated trauma(s) but no PTSD symptom profile. Both groups answered a questionnaire addressing the recollective quality, integration and coherence of the traumatic memory that currently affected them most. Participants with a PTSD symptom profile reported more vivid recollection of emotion and sensory impressions. They reported more observer perspective in the memory (seeing themselves ‘from the outside’), but no more fragmentation. They also agreed more with the statement that the trauma had become part of their identity, and perceived more thematic connections between the trauma and current events in their lives. The two groups showed different patterns of correlations which indicated different coping styles. Overall, the findings suggest that traumas form dysfunctional reference points for the organization of other personal memories in people with PTSD symptoms, leading to fluctuations between vivid intrusions and avoidance. Copyright © 2003 John Wiley & Sons, Ltd.
Memory biases in gymnastic judging: differential effects of surface feature changes
Authors: Ste‐Marie Diane
Published: September 2003

An Erratum has been published for this article in Applied Cognitive Psychology 18 (3) 2004, 371.

Three experiments examined whether changes in stimuli features would affect the pattern of memory biases reported by Ste‐Marie and colleagues (1991, 1996, 2001). Experiment 1 served as a replication of Ste‐Marie and colleagues' findings with new stimuli. In Experiments 2 and 3, surface features of the gymnastic stimuli were altered from that presented in the study phase for both perceptual (implicit memory test) and recognition test (explicit memory test) phases. In Experi‐ment 2, the bodysuit that was worn by the gymnast was changed between the study phase and test phase presentation, whereas it was the gymnast who performed the gymnastic element that was changed in Experiment 3. Memory biases were still evident, despite the stimulus feature change of the bodysuit. In contrast, memory biases were significantly reduced when there was a change in the gymnast performing the element. Discussion is focused on the activation of memory representations underlying these effects and the nature of task relevance for memory biases in gymnastic judging. In addition, specific recommendations for the gymnastic competition setting are included as the findings suggest that judges' objectivity can be compromised by these memory biases. Copyright © 2003 John Wiley & Sons, Ltd.
Memory bias in the recall of pre‐exam anxiety: the influence of self‐enhancement
Authors: Dewhurst Stephen A. , Marlborough Michelle A.
Published: September 2003

Previous research has shown that students asked to recall the anxiety levels they reported prior to an exam exaggerate how anxious they had been. The present study investigated the effect of current emotions on this memory bias by comparing the recall of pre‐exam anxiety in students who either achieved or failed to achieve their target grades. Participants rated their anxiety levels 48 hours prior to the exam and were asked to recall these levels after receiving their exam results. The exaggerated recall of pre‐exam anxiety was observed only in students who surpassed their target grade. Students who failed to achieve their target grade significantly underestimated their pre‐exam anxiety levels. The findings are attributed to self‐enhancement motives that bias the recall of pre‐exam anxiety in the direction that maximizes self‐esteem. Copyright © 2003 John Wiley & Sons, Ltd.
The role of perspective in locating position in a real‐world, unfamiliar environment
Authors: Iachini Tina , Logie Robert H.
Published: September 2003

This paper reports an exploration of how perspective information contributes to localizing and orienting oneself in a real‐world, unfamiliar environment. Participants were asked to recognize their positions on a three‐dimensional map by observing real buildings from different perspectives set at viewpoints between 0° and 180° from a starting position. Results showed that participants were able to use remembered perspective information to locate their subsequent, different position in the correct area of space. They also showed a linear increase in rotation times as the angular distance increased between initially perceived perspective and test position. This finding suggests that the representation of the spatial information acquired from a real world large‐scale environment is orientation dependent. Copyright © 2003 John Wiley & Sons, Ltd.
Unravelling the effects of sequential presentation in culprit‐present lineups
Authors: Memon Amina , Gabbert Fiona
Published: September 2003

It is well established that sequential presentation of faces in an eyewitness situation can reduce false identification rates. The effect of a sequential presentation on the probability of accurately identifying a culprit when present in a lineup is less clear. The current study examined the efficacy of the sequential procedure in culprit present lineups approximating the real life condition where a person's appearance has changed between the time they were seen and the identification. Young (17–33 years) and older (58–80 years) witnesses viewed a video of a crime and then engaged in some filler tasks. Later they viewed a culprit‐present lineup presented in a simultaneous or sequential format. Some witnesses viewed lineups in which target appearance (hairstyle) had changed and some where it had not. Sequential testing was associated with fewer choices (hits and foil choices) as compared to simultaneous testing. A change of appearance lowered hit rates in sequential test conditions among young adults. Finally, participants in sequential conditions were more likely to report that they expected the target to be present in the lineup. We advise policy makers not to advocate sequential testing until we have a full understanding of the conditions under which the sequential‐superiority effect may be observed. Copyright © 2003 John Wiley & Sons, Ltd.
Patterning of Gold Substrates by Surface‐Initiated Polymerization
Authors: Dyer D.J.
Published: September 2003

The design and synthesis of durable and functional organic coatings is an important topic in contemporary polymer science. The well‐defined patterning of inorganic substrates is highlighted with an emphasis on planar gold. New advances in contact printing and surface initiated polymerization promise unprecedented control of the polymer architecture in the micrometer and nanometer range.
A Highly Stable, New Electrochromic Polymer: Poly(1,4‐bis(2‐(3′,4′‐ethylenedioxy) thienyl)‐2‐methoxy‐5‐2″‐ethylhexyloxybenzene)
Authors: Sonmez G. , Meng H. , Zhang Q. , Wudl F.
Published: September 2003

A highly stable new electrochromic polymer, poly(1,4‐bis(2‐(3′,4′‐ethylenedioxy)thienyl)‐2‐methoxy‐5‐2″‐ethylhexyloxybenzene) (P(BEDOT‐MEHB)) was synthesized and its electrochemical and electrochromic properties are reported. P(BEDOT‐MEHB) showed a very well defined electrochemistry with a relatively low oxidation potential of the monomer at + 0.44 V versus Ag/Ag+, E1/2 at – 0.35 V versus Ag/Ag+ and stability to long‐term switching up to 5000 cycles. A high level of stability to over‐oxidation has also been observed as this material shows limited degradation of its electroactivity at potentials 1.4 V above its half‐wave potential. Spectroelectrochemistry showed that the absorbance of the π–π* transition in the neutral state is blue‐shifted compared to PEDOT, displaying a maximum at 538 nm (onset at 640 nm), thus giving an almost colorless, highly transparent oxidized polymer with a bandgap of 1.95 eV. Different colors observed at different oxidation levels and strong absorption in the near‐IR make this polymer a good candidate for several applications.
Nanocomposite Electrolytes with Fumed Silica and Hectorite Clay Networks: Passive versus Active Fillers
Authors: Walls H.J. , Riley M.W. , Singhal R.R. , Spontak R.J. , Fedkiw P.S. , Khan S.A.
Published: September 2003

The use of nanocomposites constitutes a versatile and robust approach in the development of novel electrolytes with tailored electrochemical and mechanical characteristics. In this study, we examine the morphology, rheology, and ion‐transport properties of two types of nanocomposite electrolyte gels, one consisting of branched silica nanoparticles and the other composed of hectorite clay. In the first system with hydrophobic (fumed) silica, oligomers of poly(ethylene oxide) (PEO), and lithium salt, the silica acts as a passive filler and does not participate in ion transport. The electrochemical properties are controlled by the salt–PEO electrolyte, allowing for ionic conductivities greater than 10–3S cm–1at ambient temperature. At sufficiently high concentrations, the silica forms an elastic gel possessing a large open network structure that provides for unimpeded ion mobility. In the second system composed of lithium‐exchanged hectorite filler, the nanoscale platelets serve as the anion. This active filler yields ionic conductivities in excess of 10–4S cm–1and lithium transference numbers approaching unity. Similar to fumed silica, the hectorite clay also forms an elastic gel network. However, the morphologies of the two systems are distinctively different both in terms of network structure and characteristic length scale. These morphological differences manifest themselves in different rheological responses with regard to gel modulus and yield stress.
High‐Performance, Monolithic Polyaniline Electrochemical Actuators
Authors: Sansiñena J.‐M. , Gao J. , Wang H.‐L.
Published: September 2003

New polyaniline (PANI) asymmetric membranes were fabricated using a phase‐inversion technique with hexane as the coagulation bath. These membranes exhibit a dense structure with macrovoids distributed asymmetrically throughout the cross‐section. A stress–strain study demonstrated that the Young's modulus (1.421 GPa) and strain at break (7.6 %) of the new PANI asymmetric membranes prepared from hexane are approximately 12 and 4 times higher, respectively, than the values reported previously for the PANI integrally skinned asymmetric membranes (ISAMs) (123 MPa Young's modulus and 1.8 % strain at break). Furthermore, monolithic electrochemical actuators based on a single PANI asymmetric membrane were constructed, and a bending movement of up to 20 Hz was experimentally recorded in a hydrochloric acid aqueous solution. A lifetime of over 329 500 cycles was determined for these actuators at a ± 2° angular displacement (5 Hz). The lifetime is limited by a bending fatigue that creates a transversal crack on the PANI membrane at the air–water interface. Control over the actuator movement is also manifested by the linear dependences of the bending angle on the charge and of the angular velocity on the current. These relationships are independent of both the kind of applied electric signal and the frequency used.
Assembly of Photopolymerizable Discotic Molecules on an Aligned Polyimide Layer Surface to Form a Negative Retardation Film with an Oblique Optical Axis
Authors: Ge J.J. , Hong S.‐C. , Tang B.Y. , Li C.Y. , Zhang D. , Bai F. , Mansdorf B. , Harris F.W. , Yang D. , Shen Y.‐R. , Cheng S.Z.D.
Published: September 2003

Ultraviolet (UV) polymerizable discotic liquid‐crystalline (DLC) molecules (2,3,6,7,10,11‐hexakis(4′‐acryloy‐m‐alkyloxybenzoyoxy)triphenylene [HAHBT‐m, where m was the number of methylene units, and here m = 6 (HAHBT‐6)]) were assembled to form a negative retardation film with an oblique optical axis on a specifically designed rubbing‐aligned polyimide layer surface [6FDA‐11CBBP (where 11 is the number of methylene units in the side chains)]. The side chains of this polyimide were terminated by cyanobiphenyl groups. Surface‐enhanced Raman scattering (SERS) and optical second harmonic generation results showed that rubbing caused a surface structural re‐arrangement in the alignment layer resulting in a negative pre‐tilt angle (θs) of –8.5° (which was in the direction opposite to the rubbing direction). The molecular topology at the rubbed surface was governed by a stable fold‐like bent structure of the cyanobiphenyl side chains, in which the CN groups preferentially pointed down towards the surface. When the DLC molecules were deposited onto the alignment surface and polymerized via UV irradiation to generate a new optical film, an oblique optical axis with an average tilt angle of –18.6° with respect to the film normal was detected using ellipsometric measurements. This tilted optical axis was developed by the DLC molecules being wedged on top of the cyanobiphenyl groups when in the bent conformation. Furthermore, the tilt angle difference between the θs at the alignment surface and at the air interface of the DLC molecules was attributed to a splay deformation of the DLC molecules along the film surface normal. Optical modeling has also confirmed our experimental observations.
Block Copolymer Surface Reconstuction: A Reversible Route to Nanoporous Films
Authors: Xu T. , Stevens J. , Villa J.A. , Goldbach J.T. , Guarini K.W. , Black C.T. , Hawker C.J. , Russell T.P.
Published: September 2003

Thin films of block copolymers have been used as templates and scaffolds for the fabrication of arrays of nanostructured materials. In general, a chemical modification of the film or the removal of one of the components by photodegradative methods is required to produce a nanoporous film that serves as a template or scaffold. Here, however, the preferential interaction of one of the components with a solvent is shown to produce a reconstruction of the block copolymer film that, upon drying, leads to the generation of a nanoporous template. The area density of the pores is identical to that of the original copolymer thin film. Since no chemical reactions occurr, the process is fully reversible. Upon heating the copolymer film above its glass‐transition temperature, mobility is imparted to the copolymer and the original copolymer film with oriented domains is recovered. The film reconstruction significantly simplifies the generation of nanoporous templates.
Synthesis of New Europium Complexes and Their Application in Electroluminescent Devices
Authors: Sun P.P. , Duan J.P. , Lih J.J. , Cheng C.H.
Published: September 2003

Several substituted phenanthrolines (L = pyrazino[2,3‐f][1,10]phenanthroline (PyPhen), 2‐methylpyrazino[2,3‐f][1,10]phenanthroline (MPP), dipyrido[3,2‐a:2′,3′‐c]phenazine (DPPz), 11‐methyldipyrido[3,2‐a:2′,3′‐c]phenazine (MDPz), 11,12‐dimethyldipyrido[3,2‐a:2′,3′‐c]phenazine (DDPz), and benzo[i]dipyrido[3,2‐a:2,3‐c]phenazine (BDPz)) were successfully prepared and europium complexes Eu(TTA)3L (Eu‐L) based on these ligands were synthesized from EuCl3, 2‐thenoyltrifluoroacetone (TTA) and L in good yields. Irradiation at the absorption band between 320–390 nm of all these europium complexes, except Eu‐BDPz, in solution or in the solid state leads to the emission of a sharp red band at ∼ 612 nm, a characteristic Eu3+ emission due to the transition 5D0 → 7F2. No emission from the ligands was found. The result indicates that complete energy transfer from the ligand to the center Eu3+ ion occurs for these europium complexes. In contrast, the photoluminescence spectrum of Eu‐BDPz exhibits a strong emission at around 550 nm from the coordinated BDPz ligand and a weak emission at 612 nm from the central europium ion. Incomplete energy transfer from the ligand to the central Eu3+ ion was observed for the first time. Several electroluminescent devices (A–I) using Eu‐PyPhen, Eu‐MPP, Eu‐DPPz, and Eu‐DDPz as dopant emitters with the device configuration: TPD or NPB (50 nm)/Eu:CBP (1.7–7 %, 30 nm)/BCP (20–30 nm)/Alq (25–35 nm) (where TPD: 4,4′‐bis[N‐(p‐tolyl)‐N‐phenylamino]biphenyl; NPB: 4,4′‐bis[1‐naphthylphenylamino]biphenyl; CBP: 4,4′‐N,N′‐dicarbazole biphenyl; BCP: 2,9‐dimethyl‐4,7‐diphenyl‐1,10‐phenanthroline; Alq: tris[8‐hydroxyquinoline]aluminum) were fabricated. Some of these devices emit saturated red light and are the only europium complex‐based devices that show a brightness of more than 1000 cd m–2.
Functionalization of Poly(ethylene terephthalate) Film by Pulsed Plasma Deposition of Maleic Anhydride
Authors: Hu J. , Yin C. , Mao H.‐Q. , Tamada K. , Knoll W.
Published: September 2003

Poly(ethylene terephthalate) (PET) films have been functionalized with carboxyl groups by pulsed plasma polymerization of maleic anhydride (MA). The preserved anhydride groups of MA were converted to carboxyl groups by subsequent hydrolysis. Fourier‐transform infrared spectroscopy (FTIR) and X‐ray photoelectron spectroscopy (XPS) were used to determine the chemical composition of the deposited MA plasma polymers. Atomic force microscopy (AFM) observations visually confirmed the coverage of the PET surface with plasma polymers after water treatment of the processed PET substrate, and the functionality in the XPS spectra of samples before and after water treatment indicated the persistence of functional groups and the good adhesion of the deposited layers on the PET substrate. In accordance with FTIR and XPS results, the density of carboxyl groups increased with decreasing plasma duty cycle. Compared with the pristine PET substrate, a higher roughness was observed on the modified PET surface by AFM. The roughness decreased sharply with decreasing plasma duty cycle.
Photoreplicated Anisotropic Liquid‐Crystalline Lenses for Aberration Control and Dual‐Layer Readout of Optical Discs
Authors: Stapert H.R. , del Valle S. , Verstegen E.J.K. , van der Zande B.M.I. , Lub J. , Stallinga S.
Published: September 2003

This work describes the functional characterization of novel photoreplicated anisotropic lenses obtained from molds with different curvatures. These lenses were prepared by the photopolymerization of mixtures of a reactive liquid‐crystalline bisacrylate and non‐reactive derivatives of liquid‐crystalline cyanobiphenyl. The phase diagrams, the polymerization kinetics as a function of temperature, and the birefringence as a function of temperature for various mixtures were determined. For the fabrication of lenses, the average liquid‐crystal (LC) director of the mixtures has to be aligned in a single direction. Photoalignment and rubbing techniques were investigated to create a monodomain of the reactive material. Finally, optimal mixtures were used for the fabrication of anisotropic lenses. Aberrations were below 20 mλ root mean square (rms), which makes these LC lenses interesting for application in light paths, for example, as spherical aberration correction devices for dual‐ (or multiple‐) layer optical storage.
Structural and Spectroscopic Studies on Mesoporous Tantalum Oxide–Sodium Fulleride Composites with Conducting Fulleride Columns in the Pores
Authors: Skadtchenko B.O. , Trudeau M. , Schurko R.W. , Willans M.J. , Antonelli D.
Published: September 2003

Mesoporous tantalum oxide–sodium fulleride composites were synthesized by solution impregnation and characterized by elemental analysis, X‐ray diffraction (XRD), Raman spectroscopy, nitrogen adsorption–desorption, X‐ray electron photoelectron spectroscopy (XPS), superconducting quantum interference device (SQUID) magnetometry, variable‐temperature electron transport measurements, and solid‐state 13C and 23Na NMR spectroscopy. The room temperature conductivity pattern as a function of sodium reduction level displayed a minimum at n = 3.0 and a maximum at n = 4.5, where n is the formal charge on the fulleride. The variable‐temperature conductivity measurements demonstrated that the n = 0.5 and n = 4.5 materials were semiconductors. Solid‐state 23Na NMR spectroscopy of the n = 0.5 composite exhibited three Na environments in the composites: two associated with the tantalum oxide walls and a third associated with the fulleride. The n = 3.0 and n = 4.5 materials showed a large build‐up of Na ions in the wall with no visible Na resonances associated with the fulleride, suggesting a structure in which the fulleride units exist as naked anions in one‐dimensional chains surrounded first by a layer of Na ions and then by a layer of mesoporous tantalum oxide. Solid‐state 13C NMR experiments showed more than one fulleride species in both the n = 0.5 and the n = 4.5 composites, as well as pure C60 in the n = 0.5 material, but almost exclusively C603– in the n = 3.0 material. The retention of carbon throughout reduction suggests that polymerization may have occurred, however this could not be verified by 13C NMR spectroscopy, because the region where sp3 fullerene resonances normally appear was obscured by solvent peaks.
Surface Polymerization of Hydrophilic Methacrylates from Ultrafine Silica Sols in Protic Media at Ambient Temperature: A Novel Approach to Surface Functionalization Using a Polyelectrolytic Macroinitiator
Authors: Chen X. , Armes S.P.
Published: September 2003

A convenient one‐pot synthesis of polymer‐grafted nano‐sized silica particles using atom transfer radical polymerization (see Figure) is described. Physical adsorption of a cationic macroinitiator allows polymerization of a range of hydrophilic methacrylates. A high degree of coverage of the silica sol particles by the grafted polymer chains was indicated.
Novel Silica Nanotubes with a High Aspect Ratio—Synthesis and Structural Characterization
Authors: Zygmunt J. , Krumeich F. , Nesper R.
Published: September 2003

Vanadium oxide hydrate has been used in a new, robust, and inexpensive shape‐templating synthesis leading to silica nanotubes (SiO2‐NTs, see Figure) with good chemical purity, a well‐defined morphology, and high aspect ratio. Unidimensional nanosized cavities or channels are made accessible through the open ends of the SiO2‐NTs, which can be functionalized, thus generating particles with magnetic, catalytic, or uptake/release behavior.
Controlling the Field‐Effect Mobility of Regioregular Polythiophene by Changing the Molecular Weight
Authors: Kline R.J. , McGehee M.D. , Kadnikova E.N. , Liu J. , Fréchet J.M.J.
Published: September 2003

A clear dependence of the hole mobility on molecular weight of poly(3‐hexylthiophene) in films is demonstrated. The charge carrier mobility of regioregular polythiophene is shown to increase by four orders of magnitude as the molecular weight is increased from ∼3 200 g mol–1 to 36 000 g mol–1. These observations could explain why the mobility values obtained in different labs vary so widely and suggest that optimizing the molecular weight of conjugated polymers could lead to significant improvements in device performance.
Optimizing DNA yield from buccal swabs in the elderly: Attempts to promote buccal cell growth in culture
Authors: Vandenbergh David J. , Anthony Kate , Whitfield Keith E.
Published: September 2003

Participation in genetic studies is often limited by a volunteer's reluctance to donate blood samples. We wished to determine if alternate, less painful, methods to venipuncture could be used to collect cells to provide DNA for genotyping, and whether the cells could be grown in culture for extraction of DNA. Volunteers in the study were comprised of two groups. Nine individuals from a university campus were recruited to provide samples for initial experiments. A second group of 710 twins and singletons from North Carolina and of African‐American descent were a part of an ongoing study of age‐related traits and participated in collection of buccal swabs via the mail. A protocol was generated that maximizes the recovery of DNA from buccal swabs, which are easier to handle than saline rinses. The DNA recovered is stable over several years, allowing genotype tests at a future date. Attempts to encourage growth of buccal epithelial cells recovered from swabs in tissue culture proved unsuccessful. Buccal swabs work well for the collection of DNA, especially from nonclinic‐based volunteers, and can be sent via the mail to the laboratory for DNA extraction. Thus, an inexpensive and efficient method exists for genetic studies of population‐based samples. Am. J. Hum. Biol. 15:637–642, 2003. © 2003 Wiley‐Liss, Inc.
Attention‐Deficit hyperactivity disorder (AD/HD) and fluctuating asymmetry (FA) in a college sample: An exploratory study
Authors: Burton C. , Stevenson J.C. , Williams D.C. , Everson P.M. , Mahoney E.R. , Trimble J.E.
Published: September 2003

Departures from normal development can be partly assessed by measuring fluctuating asymmetry (FA), that is, differences from perfect symmetry in traits that display bilateral symmetry. Attention‐deficit hyperactivity disorder (AD/HD), one of the most common psychiatric conditions, is diagnosed if there are developmentally inappropriate levels of inattention, hyperactivity, and impulsivity. The objective here is to measure whether AD/HD behaviors positively correlate with FA in head, hands, and fingerprints of a sample of college students (n = 176, 57 male, 119 female) not selected for AD/HD. FA was measured as the absolute value of the difference between right and left sides divided by group mean trait size. Average FAs (mean, SE) were lowest for finger lengths (e.g., male, 3rd, 0.011 ± 0.001; female, 3rd, 0.012 ± 0.001) and highest for digit ridge counts (e.g., male, 5th, 0.075 ± 0.007; female, 2nd, 0.069 ± 0.005). Average FAs were similar between the sexes and only one facial measure and the facial index (summed FAs) differed significantly between the sexes (F > M). The scores for measures of the adult AD/HD behavioral assessment instrument, the Wender Utah Rating Scale (WURS) were high overall in this sample and males exhibited higher rates of symptoms than females. A Rasch measurement model analysis of individual responses to the WURS produced a true interval score for each person that is a measure of individual “AD/HDness.” FA indices were then regressed on Rasch scores. A univariate analysis of all the variables demonstrated a significant interaction of sex. Hand, Dermatoglyphic, Face, and Total Indices were then regressed by sex on the Rasch values of “AD/HDness.” Only in males was there a trend for the Dermatoglyphic Index (F1,55 = 3.627, P = 0.062) and Total Index (F1,55 = 3.811, P = 0.056) to increase as AD/HDness increases. Am. J. Hum. Biol. 15:601–619, 2003.© 2003 Wiley‐Liss, Inc.
Male/female weight of internal organs: Examination across multiple populations
Authors: Spencer Richard P.
Published: September 2003

For internal organ weights in the 50th percentile, the male/female weight relationship was examined by use of autopsy data in eight populations. Values were closely coupled (P < 0.001), so that male organ weight could be expressed as a linear function of the corresponding female organ. A variant, in a reported population from India, was noted. The concept of “allometric mass exponent” was also applied to relating male/female organ weights, with close agreement. To examine if findings correlated with height and weight of the whole body, male height was expressed as a function of the female value in each population. There was close agreement. Correlation was also noted when male body weight was given as a function of female body weight. Am. J. Hum. Biol. 15:643–646, 2003. © 2003 Wiley‐Liss, Inc.