bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Effluents Derived from Palm Oil Extraction Plants on Soil Microbial Community
Authors: Akubuenyi F. C. , Sylvanus K. H.
Published: February 2023

In order to know the consequences of the effluent on the microflora of the soil and its respective fertility, the size of the experimental sample was defined, which was represented by five locations, from which ten portions of soil were collected for microbiological analysis. Unimpacted soil samples served as controls. Total counts of heterotrophic bacteria, coliforms, and fungi were assessed using the pour plate and spread plate method. The result showed that the counts of total heterotrophic bacteria, total coliforms and total fungi (3.8x103CFU/mL, 3.5x103CFU/mL and 3.4x102CFU/mL respectively) of the impacted soils were lower compared to the values (3.6x106 CFU/mL, 3.6x106CFU/mL and 2.6x104UFC/mL respectively) of the non-impacted soils that served as control. Bacterial genera involved in margarine production processes include Bacillus spp, Micrococcus spp, Klebsiella spp, Pseudomonas spp, Staphylococcus spp, Salmonella spp. The genera of fungi isolated from soils with effluents from palm oil extracting plants include Aspergillus spp, Rhizopus spp and Mucor spp. The results obtained indicate that effluents from palm oil extracting plants have an immediate negative impact on the microbiota of the soil, since its application could cause changes that affect the microbial communities. Therefore, it is recommended that adequate guidelines be established for the possible pre-treatment and safe discharge of effluents from palm oil mills, in addition to avoiding their effect on the microbiota and soil fertility.
Challenges and Experiences of Pre-service Teachers in Teaching Internship during the New Normal
Authors: Pattung Agustina G. , Caban Reymarie M.
Published: February 2023

Teacher Education Institutions (TEIs) in the Philippines were enjoined to implement the necessary modifications in the delivery of teaching internship given their context and available resources during the global Covid- 19 pandemic. Teaching internship courses were made experiential, using the different new normal learning modalities; developmental through coaching and mentoring, and aligned with the Learning Continuity Plan (LCP) and Most Essential Learning Competencies (MELCs). This study aimed to determine the challenges and experienced encountered by the Apayao State College (ASC) pre- service teachers in their internship during the pandemic. The study made use of the mixed approach or combination of qualitative and quantitative approach of research. Results revealed that the mean age of the respondents is 24 years old and pre- dominantly female respondents. They were involved in the various activities of the schools during their internship. They had encountered challenges such as ICT integration, new modalities of teaching- learning, social interactions, internet connectivity and instructional material preparations. Furthermore, they identified positive learning experiences during their internship but encountered problems along ICT skills and usage, time management, skills of the students with new platforms and adjustment to no face-to-face classes during their teaching internship.
Postpartum Hemorrhage: Integrative Healthcare Services: A Comprehensive Review
Authors: Nomani Ibtesam
Published: February 2023

Background: Postpartum bleeding (PPB) and its clinical management (i.e., skin-to-skin contact and breastfeeding) are the essential parameters in which healthcare services are mandatory to promote maternal and fetal well-being. Aim: The researcher aims to investigate the broader perspectives regarding immediate skin-to-skin initial contact between baby and mother. Besides, breastfeeding significance would encourage the development of clinical outcomes' well-being. Across various institutions and globally, several integrative practices are established to promote and preserve maternal and fetal mortality and morbidity. Hence, comprehensive literature aimed to probe the cause-and-effect relationship association. Methods: The literature search was adopted using appropriate keywords and followed a standard scientific data search system. The search included PubMed and Google Scholar databases. All publications associated with immediate newborn care and bonding with mothers were the highlights of this paper. Results: The results indicate that newborn close bonding through skin-to-skin contact and breastfeeding are the cost-effective paradigm to prevent bleeding after delivery. It was also explored that the critical stages of the PPH are the transitional and fourth stages of labor.
Metal-Salen Complexes: Structural Characterization and Antibacterial Activity
Authors: Salma Ummay , Rana Md. Sohel , Ferdous Jannatul , Hossen Md. Faruk , Kudrat-E-Zahan Md. , Zamir Rausan , Asraf Md. Ali
Published: February 2023

The ligand, N,N'-bis(salicylidine)ethylenediamine or salen (L), and its complexes 1-3 with Ni(II), Cu(II) and Mn(II) were synthesized. Various analytical methods such as microanalysis, 1H-NMR, 13C-NMR, ESI-MS and FT-IR spectroscopy has been used to characterize the synthesized compounds. Antibacterial activity of the prepared compounds were tested against two Gram-positive bacteria Staphylococcus aureus and Bacillus subtillus and two Gram-negative bacteria Pseudomonas aeroginosa and Escherichia coli by agar well diffusion method. Antibacterial screening results indicate that the metal compounds are more biologically active than the free ligand. The variation of metal ions appears to influence their antibacterial activity toward different organisms. The mode of action of the synthesized metal complexes as antibacterial agents have also been explained.
Independent Semitotal Domination in the Join of Graphs
Authors: Susada Bryan L. , Eballe Rolito G.
Published: February 2023

A subset W \(\subseteq\) V (G) of a graph G is an independent semitotal dominating set of G, abbreviated ISTd-set of G, if W is an independent dominating set of G and every element of W is exactly of distance 2 from at least one other element of W. The independent semitotal domination number of G, denoted by \(\gamma\)it2(G), is the minimum cardinality of an ISTd-set of G. In this paper, we study the concept of independent semitotal domination in graphs and investigate the conditions for graphs on which the ISTd-sets exist. Further, the ISTd-sets of the join of any two graphs are examined. Consequently, the corresponding independent semitotal domination number of these graphs are obtained.
Evaluation of Performance for the Quantitative Traits in Tomato (Solanum lycopersicon L.) Over Seasons
Authors: Yadav Shalu , Yadav G. C.
Published: February 2023

Present investigations were carried out in tomato assess the mean performance, general mean and range for nineteen quantitative characters. Forty-five tomato hybrids were generated by crossing ten parents in randomized complete block design with three replications at the Main Experiment Station, Department of Vegetable Science, ANDUA&T, Kumarganj, Ayodhya, during winter (Rabi) season 2020-2021 and 2021-2022. The pooled estimates of mean performance for total fruit yield per plant varied from 2.35 to 3.24 kg for parents and 1.87 to 3.43 kg fruit for hybrids. The mean values over the parents and F1 hybrids were 2.51 and 2.68 kg, respectively. The highest mean performance for most desirable traits fruit yield per plant was exhibited by P6 (3.24 kg) followed by P9 (3.23 kg), P10 (3.09 kg), P5 (2.99 kg) and P4 (2.81 kg) for the parent. Among the hybrids, the highest fruit yield per plant was exhibited by P2× P5 (3.43 kg) followed by P4× P9 (3.41 kg), P4× P7 (3.30 kg), P1× P5(3.22 kg) and P4× P8 (3.20 kg) in descending order.
Temperature Effect on Biogas Production from Co-digestion of Food Waste, Potash and Cow Dung
Authors: Adamma C. E. Ibeaja, , Ify L. Nwaogazie, , N. U. Udeh,
Published: February 2023

Temperature influence on biogas production from co-digestion of substrate (food waste, potash and cow dung) was investigated. Different concentrations of the substrate (4% to 12%) were mixed and loaded into the anaerobic digesters to produce biogas. Results of temperature effects on the biogas volume indicated that as the days of production increased, the temperature in the digesters increases and the volume of the biogas produced also increased. For digester B1 to B5, the temperature increase ranged from 10.1 to 44.5oC while the volume of the biogas produced increased from 11.3 to 25.9; 15.3 to 30.9; 10.1 to 34.5; 18.5 to 36.0 and 18.8 to 36m3/day for digesters B1, B2, B3, B4 and B5 respectively. For digesters B6 to B9, the temperature increase ranged from 20.6 to 48.4oC while the volume of the biogas produced increased from 22.1 to 40.2; 20.6 to 41.5; 24.9 to 42.0 and 24.2 to 42.5m3/day for digesters B6, B7, B8 and B9 respectively. A total 17859.6m3 of biogas was generated for a period of 90 days. Average temperature ranges from 29.30 ± 3.00oC for digester B1 (4% concentration of sample) to 41.46 ± 4.33oC of digester B8 (11% concentration of sample). This result was further clarified from the Analysis of variance and multiple comparisons of the temperature which revealed that digesters B5, B8 and B9 had no significant difference among them. The correlation of temperature and volume of biogas generated by each digester revealed that temperature significantly influenced the quantity of biogas generated at P= 0.01 and r = 0.760 (B2G), r = 0.740(B3G), r = 0.721(B6G) and r = 0.650(B8G) showing relationship were significant and had a high relationship between temperature and the substrates.
Glioblastoma Multiforme: Molecular Biology and Updated Systematic Review on Natural Extract and Phytochemical Efficacy In-vitro
Authors: Cuschieri Andrea , Baron Byron
Published: February 2023

Glioblastoma multiforme (GBM) is the most prevalent primary malignant central nervous system tumours (CNST). Current treatment consists of surgical resection and adjuvant chemoradiotherapy, the gold-standard agent being Temozolomide (TMZ). Despite optimal treatment, GBM has an abysmal associated prognosis of approximately 15 months. The disproportionately high morbidity and mortality necessitate studies which strive to increase knowledge on putative therapeutic agents to confirm or deny their possible use against GBM Therefore, there is an urgent need to develop a deep understanding of GBM molecular biology upon which more effective therapeutic strategies may be developed.

Natural extracts and phytochemicals have shown promise as potential therapeutic agents against GBM. In this review, the molecular biology of GBM and molecular factors which contribute to therapeutic resistance are discussed in depth. The mechanisms by which phytochemicals and natural extracts exhibit can inhibit GBM growth and proliferation are discussed. Moreover, statistical analysis demonstrated that natural extracts and phytochemicals may be superior to TMZ in-vitro.

This review demonstrates that phytochemicals have great potential as novel therapeutic agents against GBM. Further preclinical and clinical studies are needed to determine the optimal doses, routes of administration, and potential toxicities of these agents, but their unique molecular targets and low toxicity profiles make them attractive candidates for further investigation.
EXPERIMENTAÇÕES ETNOGRÁFICAS EM UM AMBULATÓRIO PSIQUIÁTRICO PARA IMIGRANTES E REFUGIADAS DE SÃO PAULO
Authors: Branco Pereira Alexandre
Published: February 2023

A atuação de antropólogas em serviços de saúde não é algo usual, ao menos no Brasil. Se é possível apontar para uma profusão de pesquisas etnográficas realizadas em hospitais, o trabalho prático de antropólogas nesses ambientes costuma ser raro. Esse trabalho pretende discutir a atuação prática de um antropólogo em um serviço de saúde mental especializado em imigrantes e refugiadas localizado na cidade de São Paulo, Brasil, descrevendo as dificuldades inerentes à invenção - teórica e prática - de um exercício pouco imaginado da antropologia, pensando e propondo formas de "transformar o dado em cuidado". Além disso, pretende-se também discutir as bases epistemológicas na qual o serviço em questão repousa, problematizando a razão de o espaço para a antropologia em serviços de saúde se abrir justamente em serviços de saúde mental, em geral, e especializado no atendimento de imigrantes e refugiadas, em específico.
POÉTICAS NEGRAS NO ENCONTRO DA DANÇA COM A ANTROPOLOGIA (E VICE-VERSA):
Authors: Silveira Amanda Santos
Published: February 2023

Desejos e necessidades norteiam esta escrita. O desejo de relatar a experiência de ser artista-pesquisadora e realizar um estudo etnográfico na pós-graduação. A necessidade de dançar, desta vez, com as palavras escritas. O estudo que dá origem e sustenta o presente artigo é uma pesquisa de mestrado realizada em 2018 e 2019, que teve como objetivo compreender os processos identitários de artistas negros nas graduações em Dança na Universidade Federal de Santa Maria (UFSM). Como via para compartilhar o trabalho de campo de forma que extrapola as modalidades de apresentação consideradas mais tradicionais e formais, utilizei a etnografia como uma potência para a criação artística e performática, permitindo explorar e ampliar as interfaces entre a área artística e a antropológica. Com esse estudo, é possível concluir que o impacto causado durante as apresentações performáticas diz respeito ao caráter inovador e subversivo do uso do corpo no diálogo entre dança e etnografia.
MONTAGEM COMO PROCESSO/PERCURSO, DESMONTAGEM COMO EVENTO/RUPTURA:
Authors: Vianna Luciano von der Goltz
Published: February 2023

O presente artigo visa apresentar algumas experiências etnográficas a partir do meu trabalho de campo no Hotel da Loucura/ RJ, as quais organizam-se em torno de algumas crises epistêmicas na Antropologia sobre o método etnográfico. A partir dessas experiências esboço algumas reflexões sobre os protocolos e os treinamentos existentes para um(a) antropólogo(a) realizar seu trabalho de campo e sua etnografia, pensando-as como montagens e desmontagens de cenas, experiências, conhecimentos e sentimentos os quais parecem nunca compor um quebra-cabeça que tenha um conjunto finito de peças. Argumento que as montagens são parte de um processo de aprendizagem que compõem um percurso à deriva e a desmontagem é um evento de ruptura com o estabelecido e com o conhecido. A fim de dar corpo a esse argumento, exemplifico com algumas passagens do trabalho de campo, como tais (des)montagens podem ser produzidas no texto. Por fim, discuto sobre as relações entre jogos de montagem e suas correlações com um regime epistêmico moderno, do qual o projeto disciplinar antropológico, centrado na etnografia, é herdeiro.
VIOLÊNCIA E SUSPEIÇÃO:
Authors: Leal Jose Luis dos Santos
Published: February 2023

Fruto das reflexões do trabalho de conclusão de curso, o presente artigo discute as ações policiais que visam à busca pessoal em jovens sob a utilização motivadora da suspeição policial, suas análises partem mais especificamente para o campo simbólico e subjetivo que confronta o policial e o jovem. A pesquisa analisa a partir de elementos que compõem a “tríplice da suspeição” os mecanismos e critérios da construção do discurso para fundamentar a suspeição policial, buscando compreender a possível articulação entre acusados e a influência de filtros sociais na seleção e criminalização dos indivíduos.  A pesquisa foi realizada no ano de 2015 na comunidade da Baixada do Ambrósio, na cidade de Santana/AP, e desenvolveu-se a partir das seguintes vertentes: 1) pesquisa bibliográfica que possibilitou o contado com a literatura pertinente; 2) pesquisa etnográfica com a realização de entrevistas abertas e semiestruturadas com moradores do bairro e policiais militares da UPC (Unidade de Policiamento Comunitário). A pesquisa analisa ainda, como os policiais constroem o discurso que define quem é, ou não um suspeito. Assim, parte-se da hipótese que a suspeição não é aleatória, mas sim, seletiva e sistemática. É um processo inquisitório pelo qual identidades são construídas e/ou atribuídas para habitar adequadamente no que é representado como um suspeito.
ÁGUA, PAISAGENS E CONFLITOS:
Authors: Nascimento Renato
Published: February 2023

Este artigo tem por objetivo tecer algumas reflexões etnográficas sobre os modos de vida dos habitantes do Vale do Rio Salitre, localizado no semiárido baiano.  Apoiado em narrativas locais e tendo o Projeto Salitre de Irrigação como referência de descaso planejado e de violência administrada, faço uma descrição das trajetórias de vidas, modos de ser, viver e habitar dos salitreiros, buscando evidenciar as conexões que essas vidas estabelecem com o rio, a água, as comunidades e povoados localizados ao longo do Vale. Para isso, concebo metodologicamente a água como fato social total, analisando sua presença nos diferentes domínios da vida social dos agricultores familiares do Vale do Rio Salitre.
Structure and differential response to abscisic acid of two promoters for the cytosolic copper/zinc‐ superoxide dismutase genes, SodCcl and SodCc2, in rice protoplasts
Authors: Sakamoto Atsushi , Okumura Takekazu , Kaminaka Hironori , Sumi Kazuhiko , Tanaka Kunisuke
Published: July 2002

We determined the 5′‐flanking sequences of two nuclear genes (SodCcl and SodCcl) encoding cytosolic copper/zinc‐superoxide dismutase in rice (Oryza sativa L.). Utilizing transient β‐glucuronidase (GUS) reporter assays, functional promoter—GUS analysis was performed in rice protoplasts exposed to the phytohormone abscisic acid (ABA) or the antioxidant sulfhydryl reagent, dithiothreitol (DTT). Transcriptional activities from both SodCc—GUS fusions were stimulated by DTT, which induces the promoter activity of the tobacco SodCc gene [Proc. Natl. Acad. Sci. USA 90 (1993) 3108–3112]. ABA had no effect on SodCcl—GUS expression but specifically induced the gene expression of the SodCcl—GUS fusion. The simultaneous application of ABA and gibberellin A3, however, abolished the enhancing effect of ABA. These results indicated that two rice SodCc promoters differentially respond to externally supplied ABA and that one of the regulatory factors for plant SodCc expression is ABA in addition to cellular redox‐modulating antioxidants.
Evaluation of combinations of procedures in cesarean section
Authors: Stark M. , Chavkin Y. , Kupfersztain C. , Guedj P. , Finkel A.R.
Published: July 2002

Objective: To evaluate a procedure for cesarean section, consisting of a number of surgical techniques adopted from various sources and further developed. Methods: The principal elements of the cesarean section procedure followed were: the Joel‐Cohen method for opening the abdomen, suturing the uterus in one layer, and non‐closure of the visceral and parietal peritoneal layers. The postoperative recovery of women who underwent this procedure (JCl−− group) was compared with that of women who had undergone a Pfannenstiel incision, in which the uterus is sutured in two layers, and both peritoneal layers sutured (Pf2++ group). Results: The incidence of postoperative febrile morbidity was 7.7% in the JCl−− group compared with 19.8% in the Pf2++ group (P < 0.05). Adhesions were found in 6.3% of repeat operations after the JCl−− operation compared with 28.8% after the Pf2++ operation (P < 0.05), and there was a non‐significant trend toward fewer postoperative analgesics in the JCl−− group. Conclusion: The cesarean section procedure we have devised is not only safe, but has a lower risk of long‐ and short‐term complications.
Deficiency of a STE20/PAK family kinase LOK leads to the acceleration of LFA‐1 clustering and cell adhesion of activated lymphocytes
Authors: Endo Junji , Toyama-Sorimachi Noriko , Taya Choji , Kuramochi-Miyagawa Satomi , Nagata Kisaburo , Kuida Keisuke , Takashi Tohru , Yonekawa Hiromichi , Yoshizawa Yasuyuki , Miyasaka Nobuyuki , Karasuyama Hajime
Published: July 2002

Lymphocyte‐oriented kinase (LOK) is a member of the STE20/p21‐activated kinase (PAK) family and expressed predominantly in lymphoid organs. Generation of LOK‐deficient mice revealed that the leukocyte‐function‐associated antigen (LFA‐1)/intercellular adhesion molecules (ICAM)‐mediated aggregation of mitogen‐stimulated T cells was greatly enhanced in the absence of LOK. Though levels of total LFA‐1 and ICAMs as well as the active form of LFA‐1 on T cell blasts were comparable in the presence and absence of LOK, clustering of active LFA‐1 detected by binding of soluble ICAM‐1 was accelerated in the absence of LOK. These results suggest that LOK is potentially involved in the regulation of LFA‐1‐mediated lymphocyte adhesion.
Inactivation of glycogen synthase kinase‐3 by protein kinase C δ: implications for regulation of τ phosphorylation
Authors: Tsujio Ichiro , Tanaka Toshihisa , Kudo Takashi , Nishikawa Takashi , Shinozaki Kazuhiro , Grundke-Iqbal Inge , Iqbal Khalid , Takeda Masatoshi
Published: July 2002

The role of the phosphatidylinositol 3‐kinase (PI3K) pathway in the hyperphosphorylation of τ was investigated in SY5Y human neuroblastoma cells. Wortmannin, an inhibitor of PI3K, induced transient (after 1 h) activation of glycogen synthase kinase‐3 (GSK‐3), hyperphosphorylation of τ and dose‐dependent cytotoxicity. However, continuous inactivation of protein kinase (PK) B was observed from 1 to 24 h, suggesting the involvement of protein kinase(s) other than PKB in the phosphorylation and inactivation of GSK‐3 after 3 h. In cells treated with wortmannin, PKC δ fragments were observed, and the PKC activity increased after 3 h, whereas treatment of cells with z‐DEVD‐fmk, an inhibitor of caspase 3, also inhibited fragmentation of PKC δ and induced continuous activation of GSK‐3. It is suggested that fragmentation of PKC δ during the process of apoptosis results in the phosphorylation and inactivation of GSK‐3 and consequently inhibition of the phosphorylation of τ.
ASchistosomaprotein, Sh‐TOR, is a novel inhibitor of complement which binds human C2
Authors: Inal Jameel M. , Sim Robert B.
Published: July 2002

Human complement regulatory (also called inhibitory) proteins control misdirected attack of complement against autologous cells. Trypanosome and schistosome parasites which survive in the host vascular system also possess regulators of human complement. We have shown Sh‐TOR, a protein with three predicted transmembrane domains, located on theSchistosomaparasite surface, to be a novel complement regulatory receptor. The N‐terminal extracellular domain, Sh‐TOR‐ed1, binds the complement protein C2 from human serum and specifically interacts with the C2a fragment. As a result Sh‐TOR‐ed1 pre‐incubated with C2 inhibits classical pathway (CP)‐mediated haemolysis of sheep erythrocytes in a dose‐dependent manner. In CP‐mediated complement activation, C2 normally binds to C4b to form the CP C3 convertase and Sh‐TOR‐ed1 has short regions of sequence identity with a segment of human C4b. We propose the more appropriate name for TOR of CRIT (complement C2 receptor inhibitory trispanning).
Biophysical characterization of interactions between the core binding factor α and β subunits and DNA
Authors: Tang Yen-Yee , Crute Barbara E. , Kelley John J. , Huang Xuemei , Yan Jiangli , Shi Jianxia , Hartman Kari L. , Laue Thomas M. , Speck Nancy A. , Bushweller John H.
Published: July 2002

Core binding factors (CBFs) play key roles in several developmental pathways and in human disease. CBFs consist of a DNA binding CBFα subunit and a non‐DNA binding CBFβ subunit that increases the affinity of CBFα for DNA. We performed sedimentation equilibrium analyses to unequivocally establish the stoichiometry of the CBFα:β:DNA complex. Dissociation constants for all four equilibria involving the CBFα Runt domain, CBFβ, and DNA were defined. Conformational changes associated with interactions between CBFα, CBFβ, and DNA were monitored by nuclear magnetic resonance and circular dichroism spectroscopy. The data suggest that CBFβ ‘locks in’ a high affinity DNA binding conformation of the CBFα Runt domain.
Observations of rotation within the FoF1‐ATP synthase: deciding between rotation of the Foc subunit ring and artifact
Authors: Tsunoda Satoshi P. , Aggeler Robert , Noji Hiroyuki , Kinosita Kazuhiko , Yoshida Masasuke , Capaldi Roderick A.
Published: July 2002

FoF1‐ATP synthase mediates coupling of proton flow in Fo and ATP synthesis/hydrolysis in F1 through rotation of central rotor subunits. A ring structure of Fo
c subunits is widely believed to be a part of the rotor. Using an attached actin filament as a probe, we have observed the rotation of the Fo
c subunit ring in detergent‐solubilized FoF1‐ATP synthase purified from Escherichia coli. Similar studies have been performed and reported recently [Sambongi et al. (1999) Science 286, 1722–1724]. However, in our hands this rotation has been observed only for the preparations which show poor sensitivity to dicyclohexylcarbodiimde, an Fo inhibitor. We have found that detergents which adequately disperse the enzyme for the rotation assay also tend to transform FoF1‐ATP synthase into an Fo inhibitor‐insensitive state in which F1 can hydrolyze ATP regardless of the state of the Fo. Our results raise the important issue of whether rotation of the Fo
c ring in isolated FoF1‐ATP synthase can be demonstrated unequivocally with the approach adopted here and also used by Sambongi et al.
Apelin peptides block the entry of human immunodeficiency virus (HIV)
Authors: Zou Min-Xu , Liu Hui-Yu , Haraguchi Yuji , Soda Yasushi , Tatemoto Kazuhiko , Hoshino Hiroo
Published: July 2002

The orphan G protein‐coupled receptor APJ has been shown to be a coreceptor for human and simian immunodeficiency virus (HIV and SIV) strains. We have determined that some HIV and SIV strains use APJ as a coreceptor to infect the brain‐derived NP‐2/CD4 cells. Because apelin is an endogenous ligand for the APJ receptor, we examined the inhibitory effects of apelin peptides on HIV infection, and found that the apelin peptides inhibit the entry of some HIV‐1 and HIV‐2 into the NP‐2/CD4 cells expressing APJ. The inhibitory efficiency has been found to be in the order of apelin‐36>apelin‐17>apelin‐13>apelin‐12.
Conformational mapping of the N‐terminal segment of surfactant protein B in lipid using 13C‐enhanced Fourier transform infrared spectroscopy
Authors: Gordon L.M. , Lee K. Y. C. , Lipp M.M. , Zasadzinski J.A. , Walther F.J. , Sherman M.A. , Waring A.J.
Published: July 2002

Abstract: Synthetic peptides based on the N‐terminal domain of human surfactant protein B (SP‐B1−25; 25 amino acid residues; NH2‐FPIPLPYCWLCRALIKRIQAMIPKG) retain important lung activities of the full‐length, 79‐residue protein. Here, we used physical techniques to examine the secondary conformation of SP‐B1−25 in aqueous, lipid and structure‐promoting environments. Circular dichroism and conventional, 12C‐Fourier transform infrared (FTIR) spectroscopy each indicated a predominateα‐helical conformation for SP‐B1−25 in phosphate‐buffered saline, liposomes of 1‐palmitoyl‐2‐oleoyl phosphatidylglycerol and the structure‐promoting solvent hexafluoroisopropanol; FTIR spectra also showed significant β‐ and random conformations for peptide in these three environments. In further experiments designed to map secondary structure to specific residues, isotope‐enhanced FTIR spectroscopy was performed with 1‐palmitoyl‐2‐oleoyl phosphatidylglycerol liposomes and a suite of SP‐B1−25 peptides labeled with 13C‐carbonyl groups at either single or multiple sites. Combining these 13C‐enhanced FTIR results with energy minimizations and molecular simulations indicated the following model for SP‐B1−25 in 1‐palmitoyl‐2‐oleoyl phosphatidylglycerol: β‐sheet (residues 1–6), α‐helix (residues 8–22) and random (residues 23–25) conformations. Analogous structural motifs are observed in the corresponding homologous N‐terminal regions of several proteins that also share the ‘saposin‐like’ (i.e. 5‐helix bundle) folding pattern of full‐length, human SP‐B. In future studies, 13C‐enhanced FTIR spectroscopy and energy minimizations may be of general use in defining backbone conformations at amino acid resolution, particularly for peptides or proteins in membrane environments.
Solution structure of the amino acid sequence coded by the rarely expressed exon 26A of human elastin: theN‐terminal region
Authors: Bisaccia F. , Castiglione‐Morelli M.A. , Serafini‐Fracassini A. , Tamburro A.M. , Spisani S.
Published: July 2002

Abstract: We previously reported the structural and biological properties of the C‐terminal sequence (REGDPSSSQHLPSTPSSPRV) coded by the rarely expressed exon 26A of human elastin. It assumes a stable type II β‐turn structure spanning the REGD sequence and possesses chemotactic and immunological properties. Here the structural characterization of the sequence coded by this exon was completed. Nuclear magnetic resonance and circular dichroism studies on the N‐terminal amino acid sequence (GADEGVRRSLSPELREGD) showed the presence of an α‐helix within VRRSL and a type II β‐turn within SPEL. The smaller peptides GADEGVRRSLSP and LSPELREGD revealed structural features similar to those identified in the parent peptide. No β‐turn was found in the REGD sequence of these peptides and no chemotactic activity was detected, thereby demonstrating that this biological activity is conformation dependent. Structural studies on additional peptides such as LREGD, ELREGD and LSPELREGDPSS showed that the presence of a Glu residue two positions before the Arg residue inhibits the β‐turn formation in the REGD sequence.
The global epidemic of obesity
Authors: Tp Gill PhD, Srd, Vj Antipatis  , Wpt James
Published: July 2002

Obesity is at last being recognized as a major public health problem of global significance. More quality national obesity prevalence data are urgently needed but it is clear that rates are already high and increasing in most parts of the world. Current estimates of the global prevalence exceed 250 million. The first formal World Health Organization Consultation on obesity concluded that the global epidemic is an unintended consequence of modernization, economic development, urbanization and other societal changes. These have led to widespread reductions in spontaneous and work‐related physical activity and to excessive consumption of energy dense foods. Links between reduced growth in utero and increased risk of ill health in later life may partly explain why populations in many developing countries are especially susceptible to obesity, diabetes and heart disease when exposed to modern sedentary living. The International Obesity TaskForce has launched a global initiative for coherent action to tackle the epidemic.
Ablation of polytetrafluoroethylene (Teflon) with femtosecond UV excimer laser pulses
Authors: Küper S. , Stuke M.
Published: July 2002

Experiments on the ablation of undoped polytetrafluoroethylene (Teflon) with 300 fs UV excimer laser pulses at 248 nm are reported for the first time. In contrast to standard excimer laser pulses, these ultrashort pulses ablate Teflon with good edge quality and no signs of thermal damage for fluences down to 0.5 J/cm2 with removal rates on the order of 1 μm per pulse.
Junction field-effect transistor single quantum well optical waveguide modulator employing the two-dimensional Moss–Burstein effect
Authors: Abeles J. H. , Chan W. K. , Colas E. , Kastalsky A.
Published: July 2002

A modulation-doped junction field-effect transistor incorporating an optical waveguide under the gate modulates light by the carrier band-filling effect (two-dimensional Moss–Burstein effect) in a single quantum well, achieving a 5:1 extinction ratio in a 250-μm-long waveguide for 4 V reverse gate-source bias Vgs swing and 0 V drain-source bias Vds. Similar performance is obtained over a 16 nm spectral range. A novel band-edge transparency effect is observed for Vds>0 allowing an extinction ratio of 10:1, corresponding to a change in absorption of 92 cm−1 to be obtained through band-gap dilation by hot electrons at biases of Vds =8 V. Below-band-gap refractive index modulation of 1.6×10−3 is obtained for a Vgs swing of 2.4 V. The novel junction field-effect transistor optical modulator also functions as a photovoltaic or photoconductive optical detector, a transistor, and a light-emitting diode.
Efficient simulation technique to compute effective properties of heterogeneous media
Authors: Torquato S. , Kim In Chan
Published: July 2002

We present a new simulation technique to ‘‘exactly’’ yield effective transport properties of disordered heterogeneous media in which the transport process is governed by a steady-state diffusion equation. Hence, the algorithm, which is based upon simulating the Brownian motion of a diffusing particle, can be applied to determine the effective electrical and thermal conductivity, dielectric constant, magnetic permeability, diffusion coefficient associated with flow past fixed obstacles, and the trapping rate associated with diffusion-controlled reactions among sinks. The simulation method is shown to have a very fast execution time. The technique is illustrated by computing the trapping rate associated with diffusion-controlled reactions; it is demonstrated to have an execution time that is at least an order of magnitude faster than previous simulation methodologies.
Intersubband absorption in Si1−xGex/Si multiple quantum wells
Authors: Karunasiri R. P. G. , Park J. S. , Mii Y. J. , Wang K. L.
Published: July 2002

The intersubband infrared absorption of holes in Si1−xGex/Si multiple quantum wells is observed. The quantum well structure consists of 10 periods of 40−Å−thick Si0.6Ge0.4 wells and 300−Å−thick Si barriers. The samples are prepared using molecular beam epitaxy. In the experiment, the infrared absorption as a function of wavelength is measured using a waveguide geometry. An absorption peak near 8.1 μm has been observed, which is due to the transition between first two heavy hole bound states. The polarization dependence spectra are in good agreement with the selection rules for the intersubband transition.
Multicomponent structure in the temperature-dependent persistent photoconductivity due to different DX centers in AlxGa1−xAs:Si
Authors: Brunthaler G. , Köhler K.
Published: July 2002

The persistent photoconductivity of Si-doped AlGaAs has been investigated by temperature-dependent resistance and Hall effect measurements. After illuminating the samples at low temperature, we observe for the first time distinct structures in the temperature-dependent carrier concentration during the subsequent heating process. These structures are interpreted in terms of the existence of different DX levels below the conduction-band edge.
GaAs-based diode lasers on Si with increased lifetime obtained by using strained InGaAs active layer
Authors: Choi H. K. , Wang C. A. , Karam N. H.
Published: July 2002

Strained InGaAs/AlGaAs quantum well diode lasers have been fabricated on Si substrates for the first time. A GaAs buffer layer was grown on each Si wafer by temperature-cycled organometallic vapor phase epitaxy (OMVPE). The wafer was then transferred to a second reactor for OMVPE growth of a graded-index separate-confinement heterostructure single-quantum well laser structure. For lasers with a cavity length of 1000 μm, room-temperature pulsed threshold current densities as low as 174 and 195 A/cm2 have been obtained for active layer compositions of In0.02Ga0.98As and In0.05Ga0.95As, respectively. One laser with an In0.05Ga0.95As active layer operated cw for 56.5 h, a record lifetime for GaAs-based diode lasers on Si.
Influence of the delta doping position in the channel on the device performance of AlGaAs/InGaAs modulation-doped field-effect transistors
Authors: Dickmann J.
Published: July 2002

We present an experimental and theoretical investigation of the influence of delta doping in the InGaAs channel on the device performance of Al0.25Ga0.75As/In0.2Ga0.8As/GaAs pseudomorphic modulation-doped field-effect transistors (MODFETs). Self-consistent calculations of the band structure were used to determine the optimum spike position to introduce the doping into the channel. The results of our calculations lead to a new device approach, the backside pulse-doped channel MODFET. The device uses a narrow doping pulse at the backside interface of the InGaAs layer. For this kind of layer structure, the calculations predict that the interaction between electrons and donors and thereby the transport properties of the electrons in the channel can be modulated with applied gate voltage. At positive gate voltage the device operates in the conventional high electron mobility transistor mode, whereas at lower voltages a metal-semiconductor field-effect transistor-like behavior is observed. This has been experimentally confirmed for devices with a 2-nm-wide doping pulse located at the backside interface of the InGaAs/GaAs layers. For these devices with 0.35-μm gate length we measured a maximum saturation current as high as 800 mA/mm with a transconductance of 430 mS/mm.
Ti/Ti-N Hf/Hf-N and W/W-N multilayer films with high mechanical hardness
Authors: Shih K. K. , Dove D. B.
Published: July 2002

Ti/Ti-N, Hf/Hf-N, and W/W-N multilayer films with very thin individual metal and metal-nitride layers were developed, with hardness of the structure much higher than that of single-layer nitride films. Hardnesses with value between 3500 and 5000 kg/mm2 or higher were observed in the multilayer films. This is an improvement over that of single-layer metal-nitride films where hardnesses between 2200 and 2800 kg/mm2 are typically achieved. The improvement is thought to be due to the fact that the grains are restricted to a very small size in the thin individual layers of the sandwich structure. The multilayer films, in general, have better adhesion and less defects than the single-layer films. These films were prepared on room-temperature substrates by a simple sputtering process and have potential applications, as in hard coatings.
Subpicosecond hot hole dynamics in highly excited GaAs
Authors: Gong T. , Fauchet P. M. , Young J. F. , Kelly P. J.
Published: July 2002

The buildup of band-edge gain is observed on a subpicosecond time scale in highly excited intrinsic GaAs. Using a kinetic model to fit the experimentally determined ‘‘gain time’’ at different wavelengths, the transient behavior of the optically injected hole temperature is determined. The data are not consistent with a simple decay of the hot hole temperature due to phonon emission processes. We show that a simple estimate of the energy transfer from electrons to holes via Coulomb scattering qualitatively accounts for the observed behavior of the hole temperature.
Improved microscratch hardness of ion-plated carbon film by nitrogen inclusion evaluated by atomic force microscope
Authors: Miyake S. , Watanabe S. , Miyazawa H. , Murakawa M. , Kaneko R. , Miyamoto T.
Published: July 2002

Nitrogen-containing carbon films where deposited by reactive ion plating under a pure nitrogen ambient. Knoop hardness, microindentation hardness, and microscratch hardness of these films were evaluated. Indentation hardness, such as Knoop hardness and microindentation hardness, is influenced by surface roughness and substrate hardness, so the effect of nitrogen inclusion on the hardness cannot be clearly evaluated. In contrast, an atomic force microscope can clearly evaluate the effect of nitrogen inclusion on scratched wear depth.
Strain relief in linearly graded composition buffer layers: A design scheme to grow dislocation-free (<105 cm−2) and unstrained epilayers
Authors: Molina S. I. , Pacheco F. J. , Araújo D. , García R. , Sacedón A. , Calleja E. , Yang Z. , Kidd P.
Published: July 2002

The strain relaxation in linearly graded composition InGaAs layers grown on (001) GaAs substrates by molecular beam epitaxy is studied by transmission electron microscopy (TEM) and double crystal x-ray diffraction (DCXRD). The dislocation distribution in these layers does not coincide with the predicted equilibrium dislocation distribution [J. Tersoff, Appl. Phys. Lett. 62, 693 (1993)]. The dislocation density in the dislocation-rich layer thickness is slightly smaller than the equilibrium density. The thickness of the dislocation-rich region is different in the [110] and [11̄0] directions. A good correspondence exists between the TEM and DCXRD strain measurements. The dislocation distribution observed by TEM has made it possible to design a scheme to grow dislocation-free and unstrained top layers on linearly graded composition buffer layers.
Growth mode transition and photoluminescence properties of Si1−xGex/Si quantum well structures with high Ge composition
Authors: Sunamura H. , Shiraki Y. , Fukatsu S.
Published: July 2002

Correlation between growth mode transition and photoluminescence (PL) properties of Si1−xGex/Si quantum wells (QWs) with high Ge composition grown by gas-source molecular beam epitaxy is investigated. With increasing Ge composition in the QWs, significant deviation from the theoretical calculation is observed for x≳0.4 in the emission energy and the activation energy obtained from the temperature dependence of integrated PL intensity. Transmission electron microscopy reveals emergence of islands for x≳0.4, implying strong correlation with the anomalous PL properties. Observed PL properties are shown to be well explained by the breakdown of two-dimensional growth. An attempt to grow luminescent QWs with flat interfaces is also presented.
Diagnostics of space plasmas (invited)
Authors: Bame S. J. , McComas D. J. , Young D. T. , Belian R. D.
Published: July 2002

Diverse plasmas have been observed in the magnetospheres of Earth and other planets, and in interplanetary space. Recently, measurements were made by a space probe at Comet Giacobini–Zinner. In these various plasma regimes investigated during the space era, plasma characteristics vary widely: particle densities range from <0.01 to 1000 per cc, energies from <1 eV to many MeV, temperatures from <1 eV to >1000 eV, and bulk flow speeds from near stationary to >1000 km/s. A variety of plasma-wave activity and instabilities characterize these plasmas. The measurements are made with several different generic types of instruments including electrostatic analyzers and systems which combine electrostatic analysis with time-of-flight or magnetic analysis in order to identify ions and their charge states. This paper outlines the plasma regimes found in space, discusses instrument design principles and constraints imposed by limited spacecraft resources, describes a few instruments, and highlights a small selection of scientific results derived from diagnostics of space plasmas.
Simple piezoelectric translation device
Authors: Niedermann Ph. , Emch R. , Descouts P.
Published: July 2002

We describe a piezoelectric device which allows continuous movement and high-resolution micropositioning, without distance limitation. Both mechanical construction and the electronics for the device are very simple. The movement is obtained via a stick-slip mechanism, and steps as small as 10 nm are obtained. A displacement speed of 0.4 mm/s has been attained, and the device was capable of carrying several times its own weight, exerting a horizontal force, or climbing a plane inclined by 7°. Due to its compact construction, the device shows prospects for miniaturization.
A double Michelson interferometer for accurate measurements of electrostrictive constants
Authors: Sterkenburg S. W. P. v. , Kwaaitaal Th. , van den Eijnden W. M. M. M.
Published: July 2002

The limitations of a Michelson He-Ne laser interferometer used to measure electrostrictive strains is analyzed. It is found that Coulomb forces from the electric leakage field lead to mechanical vibrations of the sample and sample holder to such an extent as to disturb the measurement. A new double He-Ne laser interferometer to measure the upper and the lower sides of the sample has been developed to eliminate the influence of mechanical vibrations of the sample holder. Experiments show that the error in electrostrictive expansion measurements carried out with a double interferometer can be more than a factor of 10 smaller than those resulting from measurements with a single Michelson interferometer. Noise characteristics of the double interferometer are minimized by the use of optical isolators, which leads to a decrease of the shot-noise contribution of the photodiode.
Imaging Bragg spectrometer for pinched plasma experiments
Authors: Hirano K. , Hisatome N. , Yamamoto T. , Shimoda K.
Published: July 2002

A compact Bragg spectrometer for monochromatic imaging in the soft x-ray region was designed and examined. With this spectrometer, a pinhole image is simultaneously recorded with a monochromatic image. This makes it possible to easily identify the wavelength when the location of the soft x-ray source fluctuates from shot to shot, such as in the plasma focus and Z-pinch plasma. An rubidium acid phtalate (RAP) flat crystal was examined and monochromatic images of the argon K lines around 4 Å were successfully obtained and displayed. The resolution power and dispersion obtained in situ were compared with the calculated values.
A new high-resolution two-dimensional micropositioning device for scanning probe microscopy applications
Authors: Smith A. R. , Gwo S. , Shih C. K.
Published: July 2002

We report on the development of a new two-dimensional micropositioning device, or walker, which is capable of moving across very large distances (in principle unlimited) and with a very small step size (as small as 100 Å/step) in both directions. Based on a unique tracking design, the motion is extremely orthogonal with very little crosstalk between the two directions. Additionally, there is no detectable backlash in either direction. The walker performance has been extensively tested by using a position-sensitive proximitor probe. Tests have been done between 77 and 300 K. However, we project that the walker will be able to operate at temperatures as low as 4 K. This walker system has shown extremely reliable performance in a UHV environment for use with scanning tunneling microscopy and has been especially useful for cross-sectional scanning tunneling microscopy and spectroscopy studies of semiconductor hetero- and homostructures. We show one example of results on the (AlGa)As/GaAs heterostructure system.
Scanning tunneling microscopy in UHV with an X,Y,Z micropositioner
Authors: Göken Mathias
Published: July 2002

The extremely high resolution of a scanning tunneling microscope (STM) or atomic force microscope allows the examination of local material faults like dislocations, grain boundaries, and cracks on an atomic scale. However, the visual field of a scanning probe microscope is small and, especially in UHV, it is difficult to position a probe tip directly above such faults since they are not very frequent on a specimen surface. Therefore, a STM for the quantitative examination of large areas in UHV was developed. A new three-dimensional micropositioner based on inertial slip-stick motion was built, where the vertical motion is achieved with a special seesaw-like construction. This device is very compact and allows positioning of the piezoscanner with steps down to 20 nm length. The microspositioner is designed with low weight drives and special materials for the bearings (ruby on sapphire) to avoid sticking in UHV. First applications of a STM built with this micropositioner are shown where atomic resolution is reached.
Effect of PZT and PMN actuator hysteresis and creep on nanoindentation measurements using force microscopy
Authors: Hues Steven M. , Draper Charles F. , Lee Kenneth P. , Colton Richard J.
Published: July 2002

Nanoindentation measurements performed using the atomic force microscope (AFM) are significantly affected, both with regard to indentation curve shape and quantitative values of the measurements (70% variation in measured modulus), by the well-known effects of hysteresis and creep in the lead zirconate titanate (PZT) piezoceramic actuators used to control the positioning and motion of the mechanical components of the AFM. A capacitance-based displacement calibrator has been built and it was discovered that the response of PZT ceramics may vary (up to 66%) depending upon the conditions under which the piezoceramic is calibrated. By replacing the PZT actuators with lead magnesium niobate (PMN) electrostrictive actuators, nanoindentation measurements have been obtained using the AFM that are both reproducible and quantitative.