bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear Finite Element Analysis for Concrete Deep Beam Reinforced with GFRP Bars
Authors: Said Mohamed , EL-Rakeeb Tamer Mahmoud , Salah Ahmed , Mohammed Nourhan Magdy
Published: March 2022

This work investigates the behavior of concrete deep beams reinforced with GFRP bars by conducting an experimental test on a half-scale GFRP deep beam and evaluating the findings by ANSYS software. Also, ANSYS was used to perform nonlinear finite element analysis NLFEA on five specimens with different reinforcement ratios of GFRP bars (0.15%, 0.41%, 0.53%, 0.67%, and 0.79%) to examine the influence of the GFRP reinforcement ratio on the behavior of deep beams. The outcomes of the experiment were sufficiently reflected in the analysis. The program's viability was confirmed by comparing it to accessible experimental data, and the agreement was found to be acceptable. Throughout the loading stages, the NLFEA produced a reasonable estimate of the center deflection for the test specimen. It was established that raising the specimen's reinforcement ratio led to an increase in beam capacity by (10 %, 18%, 31% and 47%) for reinforcement ratios (0.41%, 0.53%, 0.67% and 0.79%) and also the ultimate stiffness increased by (6%, 7%, 29%, and 44%) compared to specimen B1. Also found that the energy absorption enhanced by (23 %, 38 %, 106 %, and 152 %), on the opposite, this increase causes the specimen's deflection to decrease by (11 %, 17%, 52%, and 66%) by comparing to specimen B1. From the outputs results, it was found that the code provision was more conservative than the analytical model. For future work, Significant and cost-effective improvements to the manufacture of GFRP bars from locally sourced raw materials. Also, Extensive experimental work to investigate the long-term behavior of GFRP-reinforced concrete beams in harsh situations. The performance of GFRP reinforced specimens subjected to shear, fatigue, and cyclic stresses in service must be evaluated.
Indirect Vector Control of Squirrel-Cage Induction Generator
Authors: I. Alkafrawi Hussam M. , Al Aga Tarek R. S. , A. Shaheen Yaser S. , Elkafrawi Ismail M. , Ben Abdelmula Haitham Saleh Ali
Published: March 2022

Aims: This paper presents the control of the output torque of SCIG using indirect vector control (IVC) technique.

Study Design: IVC is very popular in industrial applications, which doesn’t rely on the measurement of the airgap flux because the devices that used to measure the air-gap flux is inaccurate in low speed. The IVC technique has been presented to control the torque of the generator and maintain the flux unchanged.

Methodology: The performance of the proposed system is tested using MATLAB/SIMULINK.

Results and Conclusion: Simulation results are introduced showing improvement control system performance.
Personal Life, Working Time and Job Stress on Employees’ Performance in Selected Nigerian Banks
Authors: Inemesit N. Ebito, , Moses J. Akpan, , Victoria S. Umana,
Published: March 2022

Work-life balance has become an important area of concern for employers and employees in most organizations all over the world. In this study, effort was made to investigate the influence of three variables of work-life balance namely personal life, working time and job stress on employees’ performance in select Nigerian banks. Four banks were selected for the study based on their ranking as top Nigerian banks by the Corporate Finance Institute, namely; Zenith bank, GTB, Ecobank Nigeria and First Bank of Nigeria Plc. Primary data was collected using structured questionnaire. Population of the study was 401 bankers in 21 branches of the banks, located in Akwa Ibom State. A sample size of 200 bankers was drawn from the population size using Taro Yamene’s formula for sample determination. Chebyshev Proportionate formula was further used to determine the sample proportion of each branch. Hypothesis was tested using multiple regression analysis. Computations were done by means of Statistical Package for Social Science (SPSS). Findings revealed that there was significant effect of employees’ personal life, working time and job stress on workers performance in the selected Nigerian banks. It was concluded that work-life balance variables relate to and have influence on workers performance in Nigerian banks. As such, it was recommended that Nigerian banks should establish and maintain a work family culture that encompasses personal life activities, and also implement working time options and stress management programmes as workplace support measures that include family friendly policies to help resolve work-life balance problems.
Incidence of Traumatic Ulcer among the Patients Visiting Private Dental Hospital- Retrospective Study
Authors: Selvi V. T. Thamarai , Ramani Pratibha
Published: March 2022

Introduction: Oral mucosal ulcers are one of the most common types of ulcer of which Traumatic ulcers are common and acute in nature, caused by some form of trauma to the mucous membrane in the oral cavity. It is most commonly seen in the Buccal Mucosa, Lips, and occasionally in the Palate and Lateral border of tongue. It is caused by physical, chemical or thermal trauma resulting in damage and ulcer formation.

Materials and Methods: The data for the present study n = 345 patients was collected by analysing case sheets of patients who visited Saveetha Dental College from June 2019- February 2021.  The  collected  data was  subjected  to  statistical analysis  using  the  SPSS  software  by  IBM  of  version  23.

Results: From the results of the study, Traumatic Ulcer has Male predilection with incidence rate of 62.2% compared to females with incidence of 37.7%. Most of them were in the age group of 21-30 years age group  (34.5%) and least  in the 71-85 years age group  (2.9%). Traumatic ulcer was most  common  in the Alveolar mucosa  (32.2% )

Conclusion: From the present study it can be concluded that Traumatic ulcer is more common in Males. However, Gender, Age, Oral Hygiene, Usage of Tobacco products were not significantly influencing the rate of incidence of Traumatic Ulcer.
A Study Protocol for Assessing the Effect of Pre-Emptive Oral Clonidine on Intraoperative Hemodynamics and Surgical Field Quality during Functional Endoscopic Sinus Surgery (FESS) under General Anesthesia
Authors: Khandelwal Kapil K. , Sen Jayashree
Published: March 2022

Background: Typically, endoscopic sinus surgery is reserved for patients with documented rhinosinusitis. The nasal mucosa is impregnated with supply of highly rich blood vessels, so excessive occurrence of bleeding during the procedure may obscure the visibility of the surgical area which might lead into complications. So to control the intraoperative blood loss, controlled hypotension during the surgery can be adopted. Clonidine, a centrally acting α2 agonist has antihypertensive property with decreasing sympathetic outflow. Clonidine given orally judiciously prior to surgery would potentiate the inhalation agents for hypotensive action during the anaesthetic procedure without having the disadvantages of vasodilators given intravenously. This study to assess the effects of clonidine as an oral premedicant in patients who are undergoing Functional Endoscopic Sinus Surgery.

Methodology: This prospective randomized double blinded placebo controlled study will be conducted in the department of Anaesthesia, Acharya Vinoba Bhave Rural Hospital, (DMIMS) Jawaharlal Nehru Medical College Sawangi Wardha, within the period of time of December 2020 to November 2022. Total 60 patients will be enrolled and randomized in two groups: Group C (n= 30): Patients will be given Clonidine (200 μgm); Group P (n= 30) will be Placebo group. To shrink nasal mucosal vessels, all patients will receive nasal packing of 2% xylocaine with 1:200000 adrenaline. Then, 60 minutes after study drugs are given, patients will be shifted for procedure. Using Six-point Average Category Scale, the grading of surgical field in terms of bleeding, will be done by the operating surgeon. Qualitative data will be documented with the help of percentage table, quantitative data will be presented as mean and standard deviation, student t-test will be taken for comparison among the study groups, Chi-square test will be utilized for comparison of categorical data. SPSS (Statistical Package for Social Sciences) 20.0 version will be the Software used in the analysis and p < 0.05 will be considered significant statistically.

Expected Results: Oral clonidine when used as premedicant will be effective in reducing bleeding during the procedure of Functional Endoscopic Sinus Surgery.
The convergence‐divergence duality in lectin domains of selectin family and its implications
Authors: Chou Kuo-Chen
Published: July 2002

A comparison of the three‐dimensional structures of P‐, L‐, and E‐selectin lectin domains reveals that there is a convergence‐divergence duality for the 77–107 polypeptide in the three domains; i.e. part of the peptide is folded into a closely similar conformation, and part of it into a highly different one. Since the 77–107 residues are associated with the putative binding sites of the selectin family for ligands, this kind of duality might well reflect the common character of ligands to the selectin family as well as the specificity to each of their respective receptors. The finding may be of use for rationally designing selectin inhibitors with a given specificity and possible antiadhesion drugs.
SNAREs and targeted membrane fusion
Authors: Söllner Thomas
Published: July 2002

Intracellular vesicular transport involves targeting of vesicles to their correct destination and subsequent fusion with the target membrane. These processes employ unique compartment‐specific proteins in combination with general components which act at several transport steps. This review will summarize recent progress made in identifying such a machinery whose assembly and activity is modulated by a variety of regulatory proteins.
From the Editor Vol 3 No 2
Authors: Mandell Lewis
Published: July 2002

NA
Coupon Resets Versus Poison Puts
Authors: Fields Joseph A. , Kidwell David S. , Klein Linda S.
Published: July 2002

This paper examines the valuation of the two major types of event risk indenture provisions, poison puts and coupon resets, on the debt of industrial companies. In contrast with earlier work by Crabbe (1991), we find that protection provided by poison put type ofcovenants is not valued by investors. The inclusion of coupon reset provisions, however, lowers the yield spread of new issued industrial bonds by 32 basis points. The yields on bonds with low credit quality ratings are reduced by including coupon reset provisions in the bond indentures.
MAPK‐dependent expression of p21WAF and p27kip1 in PMA‐induced differentiation of HL60 cells
Authors: Das Dipak , Pintucci Giuseppe , Stern Arnold
Published: July 2002

Treatment of HL60 cells with phorbol 12‐myristate 13‐acetate (PMA) results in growth arrest and differentiation towards the macrophage lineage. PMA‐induced changes are easily monitored by morphological changes while cells in suspension start adhering onto substrate. PMA induces rapid activation of the extracellular signal‐regulated kinases (ERKs). Activation of the ERK pathway is essential to PMA‐induced differentiation of HL60 cells. PMA also induces the expression of the cyclin‐dependent kinase inhibitors p21WAF and p27kip1, which is modulated by the use of an inhibitor of the ERK cascade. This implies that a link exists between ERK activation and p21WAF and p27kip1 induction in the process of terminal differentiation.
Characterization of tBid‐induced cytochrome c release from mitochondria and liposomes
Authors: Zhai Dayong , Huang Xingxu , Han Xuehai , Yang Fuyu
Published: July 2002

tBid, the cleaved form of Bid, can induce cytochrome c (Cyt. c) release from rat heart mitochondria more efficiently and reproducibly than that from liver or brain mitochondria. Unlike Bax, such release was not prevented by cyclosphorin A, an inhibitor of the opening of permeability transition pore. Carbonyl‐cyanide m‐chlorophenyl‐hydrazone or oligomycin also have no obvious effect on the release of Cyt. c. In contrast to ceramide, tBid‐mediated Cyt. c release from mitochondria is independent of the redox state of Cyt. c. Furthermore, Bid or tBid can directly trigger the efflux of encapsulated Cyt. c or trypsin within liposomes without involvement of other protein factors.
Adenylylsulfate reductases from archaea and bacteria are 1:1 αβ‐heterodimeric iron–sulfur flavoenzymes – high similarity of molecular properties emphasizes their central role in sulfur metabolism
Authors: Fritz Günter , Büchert Thomas , Huber Harald , Stetter Karl O. , Kroneck Peter M.H.
Published: July 2002

Highly active adenylylsulfate (APS) reductase was isolated under N2/H2 from sulfate‐reducing and sulfide‐oxidizing bacteria and archaea. It was a 1:1 αβ‐heterodimer of molecular mass ≈95 kDa, and two subunits (α≈75, β≈20 kDa). The specific activity was 11–14 μmol (min mg)−1; cofactor analysis revealed 0.96±0.05 FAD, 7.5±0.1 Fe and 7.9±0.25 S2−. The photochemically reduced enzyme had a multiline EPR spectrum resulting from two interacting [4Fe–4S] centers. The properties of the different APS reductases were remarkably similar, although the enzyme is involved in different metabolic pathways and was isolated from phylogenetically far separated organisms. A structural model is proposed, with FAD bound to the α‐subunit, and two [4Fe–4S] centers located in close proximity on the β‐subunit.
Molecular cloning, characterization and evolution of the gene encoding a new group of short‐chain α‐neurotoxins in an Australian elapid, Pseudonaja textilis
Authors: Gong NanLing , Armugam Arunmozhiarasi , Jeyaseelan Kandiah
Published: July 2002

The structure and organization of five genes responsible for the synthesis of six isoforms of short‐chain α‐neurotoxins in Pseudonaja textilis venom are reported in this paper. This also forms the first report which describes the synthesis of two neurotoxin mRNA variants from one of these genes (Pt‐sntx1) as a result of alternative splicing. Each gene consists of three exons which are separated by two introns and each has a functional promoter. The promoter activity was confirmed by both CAT assay and Real‐Time PCR. A transcription initiation site, two putative TATA boxes, one CCAAT box and the transcription factor binding consensus sites for AP‐1, GATA‐2, c/EBPb were identified in the 5′ non‐coding region of each gene. Phylogenetic analysis showed that these five genes from P. textilis constituted a distinct group which has evolved by gene duplication followed by accelerated evolution from an ancestral gene.
An investigation into the mechanisms mediating plasma lipoprotein‐potentiated β‐amyloid fibrillogenesis
Authors: Stanyer Lee , Betteridge D.John , Smith Christopher C.T
Published: July 2002

The toxicity of the β‐amyloid (Aβ) peptide of Alzheimer's disease may relate to its polymerisation state (i.e. fibril content). We have shown previously that plasma lipoproteins, particularly when oxidised, greatly enhance Aβ polymerisation. In the present study the nature of the interactions between both native and oxidised lipoproteins and Aβ1–40 was investigated employing various chemical treatments. The addition of ascorbic acid or the vitamin E analogue, trolox, to lipoprotein/Aβ coincubations failed to inhibit Aβ fibrillogenesis, as did the treatment of lipoproteins with the aldehyde reductant, sodium borohydride. The putative lipid peroxide‐derived aldehyde scavenger, aminoguanidine, however, inhibited Aβ‐oxidised lipoprotein‐potentiated polymerisation, but in a manner consistent with an antioxidant action for the drug. Lipoprotein treatment with the reactive aldehyde 4‐hydroxy‐2‐trans‐nonenal enhanced Aβ polymerisation in a concentration‐dependent fashion. Incubation of Aβ with lipoprotein fractions from which the apoprotein components had been removed resulted in extents of polymerisation comparable to those observed with Aβ alone. These data indicate that the apoprotein components of plasma lipoproteins play a key role in promoting Aβ polymerisation, possibly via interactions with aldehydes.
Oxidative stress‐induced apoptosis of cochlear sensory cells: otoprotective strategies
Authors: Huang Tina , Cheng Alan G. , Stupak Howard , Liu Wei , Kim Ana , Staecker Hinrich , Lefebvre Philippe P. , Malgrange Brigitte , Kopke Richard , Moonen Gustave , Van De Water Thomas R.
Published: July 2002

Apoptosis is an important process, both for normal development of the inner ear and for removal of oxidative‐stress damaged sensory cells from the cochlea. Oxidative‐stressors of auditory sensory cells include: loss of trophic factor support, ischemia‐reperfusion, and ototoxins. Loss of trophic factor support and cisplatin ototoxicity, both initiate the intracellular production of reactive oxygen species and free radicals. The interaction of reactive oxygen species and free radicals with membrane phospholipids of auditory sensory cells creates aldehydic lipid peroxidation products. One of these aldehydes, 4‐hydroxynonenal, functions as a mediator of apoptosis for both auditory neurons and hair cells. We present several approaches for the prevention of auditory sensory loss from reactive oxygen species‐induced apoptosis: 1) preventing the formation of reactive oxygen species; (2) neutralizing the toxic products of membrane lipid peroxidation; and 3) blocking the damaged sensory cells’ apoptotic pathway.
Regional pre‐ and postsynaptic sympathetic system in the failing human heart — regulation of βARK‐1
Authors: Ungerer Martin , Weig Hans‐Jörg , Kübert Susanne , Overbeck Matthias , Bengel Frank , Schömig Albert , Schwaiger Markus
Published: July 2002

Objectives:

Regional presynaptic sympathetic innervation varies considerably in the cardiomyopathic human heart, as shown in previous studies in vivo and in vitro. The goal of the present study was to correlate markers of presynaptic sympathetic innervation with local measurement of the postsynaptic β‐adrenergic system in failing human hearts.

Methods and results:

In nine left ventricular regions of hearts explanted from patients suffering from dilated cardiomyopathy, we measured the density of uptake1 carriers ([3H]mazindol binding) as a marker of presynaptic function as well as β‐receptor density ([3H]CGP 12177 binding) and βARK‐1 levels as the pivotal compounds of postsynaptic adrenergic signal transduction. Additionally, a subgroup of the patients was examined in vivo by HED‐PET prior to heart transplantation. The density of uptake1 was related to local hydroxyephedrine (HED) retention (as determined by pre‐operative PET, r=0.65), whereas it was inversely correlated to regional βARK‐1 levels (r=−0.61, P=0.04). In contrast, β‐adrenergic receptor density was not significantly correlated either to uptake1 density or to local HED retention (r=0.15 and r=0.21).

Conclusions:

Regional βARK‐1 levels rather than β‐adrenergic receptor density were correlated with presynaptic alterations in cardiomyopathic human left ventricles. It can be assumed that in the cardiomyopathic human heart, regional β‐adrenergic desensitization might be determined by differences in local βARK levels rather than by changes in β‐receptor density.
Process Design and Costing of Bioethanol Technology: A Tool for Determining the Status and Direction of Research and Development
Authors: Wooley Robert , Ruth Mark , Glassner David , Sheehan John
Published: July 2002

Bioethanol is a fuel‐grade ethanol made from trees, grasses, and waste materials. It represents a sustainable substitute for gasoline in today's passenger cars. Modeling and design of processes for making bioethanol are critical tools used in the U.S. Department of Energy's bioethanol research and development program. We use such analysis to guide new directions for research and to help us understand the level at which and the time when bioethanol will achieve commercial success. This paper provides an update on our latest estimates for current and projected costs of bioethanol. These estimates are the result of very sophisticated modeling and costing efforts undertaken in the program over the past few years. Bioethanol could cost anywhere from $1.16 to $1.44 per gallon, depending on the technology and the availability of low cost feedstocks for conversion to ethanol. While this cost range opens the door to fuel blending opportunities, in which ethanol can be used, for example, to improve the octane rating of gasoline, it is not currently competitive with gasoline as a bulk fuel. Research strategies and goals described in this paper have been translated into cost savings for ethanol. Our analysis of these goals shows that the cost of ethanol could drop by 40 cents per gallon over the next ten years by taking advantage of exciting new tools in biotechnology that will improve yield and performance in the conversion process.
Modifications of the cyclic mu receptor selective tetrapeptide Tyr‐c[d‐Cys‐Phe‐d‐Pen]NH2 (Et): effects on opioid receptor binding and activation
Authors: McFadyen I.J. , Ho J.C. , Mosberg H.I. , Traynor J.R.
Published: July 2002

Abstract: The previously described cyclic mu opioid receptor‐selective tetrapeptide Tyr‐c[d‐Cys‐Phe‐d‐Pen]NH2 (Et) (JOM‐6) was modified at residues 1 and 3 by substitution with various natural and synthetic amino acids, and/or by alteration of the cyclic system. Effects on mu and delta opioid receptor binding affinities, and on potencies and efficacies as measured by the [35S]‐GTPγS assay, were evaluated. Affinities at mu and delta receptors were not influenced dramatically by substitution of Tyr1 with conformationally restricted phenolic amino acids. In the [35S]‐GTPγS assay, all of the peptides tested exhibited a maximal response comparable with that of fentanyl at the mu opioid receptor, and all showed high potency, in the range0.4–9 nm. However, potency changes did not always correlate with affinity, suggesting that the conformation required for binding and the conformation required for activation of the opioid receptors are different. At the delta opioid receptor, none of the peptides were able to produce a response equivalent to that of the full delta agonist BW 373,U86 and only one had an EC50 value of less than 100 nm. Lastly, we have identified a peptide, d‐Hat‐c[d‐Cys‐Phe‐d‐Pen]NH2 (Et), with high potency and > 1000‐fold functional selectivity for the mu over delta opioid receptor as measured by the [35S]‐GTPγS assay.
Two conserved domains in regulatory B subunits mediate binding to the A subunit of protein phosphatase 2A
Authors: Li Xinghai , Virshup David M
Published: July 2002

Protein phosphatase 2A (PP2A) is an abundant heterotrimeric serine/threonine phosphatase containing highly conserved structural (A) and catalytic (C) subunits. Its diverse functions in the cell are determined by its association with a highly variable regulatory and targeting B subunit. At least three distinct gene families encoding B subunits are known: B/B55/CDC55, B′/B56/RTS1 and B″/PR72/130. No homology has been identified among the B families, and little is known about how these B subunits interact with the PP2A A and C subunits. In vitro expression of a series of B56α fragments identified two distinct domains that bound independently to the A subunit. Sequence alignment of these A subunit binding domains (ASBD) identified conserved residues in B/B55 and PR72 family members. The alignment successfully predicted domains in B55 and PR72 subunits that similarly bound to the PP2A A subunit. These results suggest that these B subunits share a common core structure and mode of interaction with the PP2A holoenzyme.
Identification and characterization of a novel gene that is upregulated in leukaemia cells by nitric oxide
Authors: Shami Paul J. , Kanai Nobuko , Wang Lai Y. , Vreeke Theresa M. , Parker Charles J.
Published: July 2002

Nitric oxide (NO) inhibits growth and induces differentiation in acute myeloid leukaemia (AML) cells. To identify genes associated with these processes, we studied the effect of NO on AML gene expression using the technique of Representational Difference Analysis. Exposure of HL‐60 cells to the NO donor DETA‐NO for 24 h induced the expression of a novel gene that was named rno (regulated by nitric oxide). Treatment of HL‐60 cells with dimethyl sulphoxide induced expression of rno, but treatment with Vitamin D3 or all‐trans retinoic acid did not. Upregulation of rno by NO was cGMP independent. Northern blot analysis indicated that constitutive expression of the novel gene was limited to leucocytes. Three isoforms of rno were identified. An rno cDNA clone was obtained by screening a human leucocyte library. The nucleotide sequence of the open reading frame shared significant homology with that of the human ribonuclease/angiogenin inhibitor (RI). The predicted amino acid sequence indicated that, like RI, rno is leucine and cysteine rich and is comprised of a series of repetitive elements (leucine‐rich repeats) that may mediate macromolecular interactions. Enhancement of expression of rno may be a component of the process by which differentiation and growth inhibition of leukaemia cells is induced by NO.
Cord blood leptin concentrations in relation to intrauterine growth
Authors: Varvarigou Anastasia , Mantzoros Christos S. , Beratis Nicholas G.
Published: July 2002

OBJECTIVE

Leptin, a hormone that signals the amount of energy stores to the brain, has recently been shown to play a role in the regulation of several hypothalamic pituitary axes, including the growth hormone axis. To investigate a potential association between cord blood leptin concentrations and intrauterine growth we measured leptin concentrations in the cord blood of small for gestational age (SGA), appropriate for gestational age (AGA) and large for gestational age (LGA) healthy newborns.

PATIENTS AND MEASUREMENTS

Cord blood leptin concentrations were evaluated in 25 SGA,100 AGA, and 45 LGA, neonates.

RESULTS

Leptin was detectable in all newborns in concentrations comparable with those found in adults. Moreover, SGA newborns had lower leptin concentrations (3.70 ± 1.81 μg/l) than AGA (5.65 ± 4.98 μg/l) and LGA newborns (11.99 ± 7.06 μg/l)(P < 0.01). Cord blood leptin concentrations were significantly associated with ponderal index, cord blood insulin concentrations, placental weight and maternal serum leptin concentrations. Importantly, the association between cord blood leptin concentrations and intrauterine growth status persisted after adjusting for adiposity, placental weight, maternal serum leptin concentrations and cord blood insulin concentrations.

CONCLUSIONS

Cord blood leptin concentrations are independently associated with intrauterine growth. Future studies are needed to elucidate the underlying mechanism and clarify the role of leptin in regulating growth and controlling appetite in newborns.
Functional hypothalamic amenorrhoea: a partial and reversible gonadotrophin deficiency of nutritional origin
Authors: Couzinet Beatrice , Young Jacques , Brailly Sylvie , Le Bouc Yves , Chanson Philippe , Schaison Gilbert
Published: July 2002

OBJECTIVE

Functional hypothalamic amenorrhoea (FHA) is a consequence of low dietary intake as observed in two major pathophysiological conditions, anorexia nervosa and/or intensive physical exercise. The aim of the present study was to assess in women with FHA and normal body mass index (BMI) and apparently normal daily activities, the degree of impairment of GnRH secretion, its nutritional origin and its reversibility.

PATIENTS

Twelve women (22–35 years) with FHA not related with exercise and 12 age and BMI matched menstruating controls (NC) were studied. Six women with congenital hypothalamic hypogonadism (CHH), representative of complete gonadotrophin deficiency, were also enrolled for comparison.

DESIGN

Plasma oestradiol (E2) and androstenedione (A) levels were measured and the pulsatile profile of LH was studied. A GnRH agonist test, using 100 μg S/C of DTrp6 GnRH (Triptorelin) was performed (sampling every 2 h for 24 h). Dietary intake, body composition and nutritional markers (FT3, ferritin, retinol binding protein (RBP), SHBG, IGF‐I and leptin) were measured. All the women with FHA were advised to normalize their diet during four months. The same studies were performed if nutritional markers and body composition were normalized.

RESULTS

In FHA, mean plasma E2 and A levels were low. LH pulse frequency and amplitude were significantly reduced compared to NC (P < 0.005). FSH/LH ratio increased rapidly after triptorelin with a significant increase in plasma E2 levels between 18 and 24 h. In contrast, no response to triptorelin was observed in women with CHH.

The fat body mass was lower and the lean body mass higher in FHA than in NC. Marked differences in nutritional intake were identified, with altered dietary composition. FHA consumed significantly less fat (P < 0.001) and less carbohydrate (P = NS) than the BMI‐matched controls. Mean plasma levels of SHBG were increased whereas mean plasma levels of FT3, ferritin, RBP, IGF‐I, and leptin were significantly decreased. Only three patients with FHA kept a balanced diet and improved their body composition after 4 months. LH pulsatile profile and response to triptorelin challenge were normalized in these patients.

CONCLUSION

Mild dieting, close to normal but prolonged and characterized by an important fat restriction, is able to interfere with gonadotrophin secretion. Assessment of nutritional markers allows recognition of mild nutritional insufficiency as a common cause of FHAs. The gonadotrophin deficiency is partial and may be reversible after improvement of nutritional intake and body composition.
Multidrug resistance in oncology: diagnostic and therapeutic approaches
Authors: Robert J.
Published: July 2002

Resistance to anticancer drugs is often mediated by the overexpression of a membrane pump able to extrude many xenobiotics out of the tumour cells. The most frequently expressed of these pumps is called P‐glycoprotein and is encoded by a gene called MDR1 (for multidrug resistance). There could be great clinical interest for investigating the expression of this gene or of its product in patients' tumours, as well as in developing ways of circumventing this mechanism of resistance. Multidrug resistance can be diagnosed in tumours by molecular biology techniques (gene expression at the mRNA level), by immunological techniques (quantification of P‐glycoprotein itself) or by functional approaches (measuring dye exclusion). Numerous studies have tried to use the MDR status of tumours as a predictor of response to treatment, but they have not yet reached definitive conclusions to allow the use of this approach in routine determinations. This is because no consensus has emerged concerning the optimal technique and the best conditions for MDR determination. Continuous efforts are still required for defining appropriate standardization of the techniques. The development of MDR modulators for the treatment of resistant tumours is a promising approach requiring rigorous clinical trials with successive phase I, phase II and phase III studies. Phase I can be omitted when the reverter is already being used in therapeutics; phase II should be performed using a sequential design, in order to prove the inefficacy of the anticancer therapy before combining it to a modulator; and phase III must only be undertaken after the demonstration that responders can be recruited by the combination. However, the effect of some reverters on anticancer drug pharmacokinetics may hamper rapid evaluation. Several drugs are good candidates for MDR modulation, but definitive results are still lacking for the introduction of such combinations in standard therapeutic protocols.
Hepatitis C virus testing of plasma pools by nucleic acid amplification technology: external quality assessment
Authors: Gentili G. , Pisani G. , Bisso G. , Cristiano K. , Wirz M. , Mele C. ,   the EQA Participants
Published: July 2002

Background and Objectives

Since 1 July 1999, in accordance with European regulations, only batches of blood products obtained from plasma pools tested and found to be non‐reactive for hepatitis C virus (HCV) RNA are being released. As monitoring the performance of manufacturers involved in plasma pool testing is important to ensure reliable amplification techniques, the Istituto Superiore di Sanità, as the Italian regulatory authority, organized an external quality assessment study.

Materials and Methods

A reference HCV RNA panel calibrated in international units (IU) was sent to each participant to be tested according to the validated procedure they routinely used in plasma pool testing. The panel consisted of 20 coded samples, four of which were obtained from a negative plasma pool. The remaining 16 samples, prepared by diluting the national reference preparation (ISS HCV RNA 0498), represented four half‐log dilution series, each consisting of four samples containing 100, 32, 10 and 3·2 IU/ml of HCV RNA.

Results

The overall performance of the laboratories was very satisfactory. All laboratories correctly identified the negative samples. The 100‐ and 32‐IU/ml samples were both detected in 98·4% of the assays, while the 10‐ and 3·2‐IU/ml samples were detected in 73·4 and 50·0% of the assays, respectively. No substantial differences were observed between in‐house procedures and commercial kits.

Conclusion

This external quality assessment study showed that manufacturers of blood products have reached a high level of proficiency that fully complies with the European Pharmacopoeia requirements. This finding is reassuring in the context of the safety of blood products.
Refractive error changes in mixed astigmatism
Authors: Goss David A.
Published: July 2002

The purpose of this note is to examine refractive error changes in children who change from mixed astigmatism to myopic astigmatism. Data were collected for 16 children who changed from mixed astigmatism to simple myopic or compound myopic astigmatism. Children with mixed astigmatism showed minimal refractive changes until they converted to myopic astigmatism, at which time refractive changes increased.
Physician‐Patient Congruence Regarding Medication Regimens
Authors: Bikowski Richard M. , Ripsin Cynthia M. , Lorraine Viki L.
Published: July 2002

OBJECTIVES:

To characterize the degree of disparity between physicians' perceptions of older patients' medication regimen and patients' perceptions of their regimen.

DESIGN:

Prospective observational. Physicians and patients were blinded at index visit; after, trained medical students made home visits, collecting information about medications that was compared with physician questionnaires.

SETTING:

Community family medicine residency program.

PARTICIPANTS:

Patients age 65 and older presenting for routine visit, taking at least four prescription medications, and seen by index physician three or more times in the past year. Physicians were family medicine faculty and second‐ and third‐year residents.

MEASUREMENTS:

Fifty physician‐patient pairs were analyzed. Average age was 75 (standard deviation (SD) ±5.5); patients averaged 7.0 prescription medications (range 3–17, SD ±2.89). Three hundred seventy‐five prescription medications were identified; the most commonly prescribed were antihypertensives (134/375; 36%).

RESULTS:

Congruence, defined as agreement between physician and patient regarding all prescription medications, dosages, and frequency, averaged 70% for faculty (range 53–89%) and 58% for residents (range 41–81%) (P = .08). Fourteen percent (7/50) demonstrated complete congruence; 74% (37/50) had at least one medication that either the physician was unaware the patient was taking or the physician thought the patient was taking but that was not part of the patient's regimen; 12% (6/50) had dose and/or frequency discrepancies.

CONCLUSIONS:

This study demonstrates significant disparity in a population where it is crucial for healthcare providers and patients to be in close agreement about intended medication regimens. J Am Geriatr Soc 49:1353–1357, 2001.
High coupled power 1.3 μm edge-emitting light-emitting diode with a rear window and an integrated absorber
Authors: Gen-ei K. , Tanioka A. , Suhara H. , Chinen K.
Published: July 2002

An InGaAsP edge-emitting light-emitting diode with a rear window and an integrated absorber is developed. Over 220 μW of coupled power is achieved, for the first time, without the use of antireflection front facet coating. Even at low ambient temperature of −40 °C the stimulated emission is well suppressed.
Boron redistribution in doping superlattices grown by silicon molecular beam epitaxy using B2O3
Authors: Jackman T. E. , Houghton D. C. , Denhoff M. W. , Kechang Song , McCaffrey J. , Jackman J. A. , Tuppen C. G.
Published: July 2002

Coevaporation of B2O3 during silicon molecular beam epitaxy has been used to prepare heavily doped superlattices (pipi’s). Full activation up to 3×1020 cm−3 (100 times the solid solubility limit) was obtained at growth temperatures below 700 °C. Significant boron redistribution has been observed into the undoped layers when the dopant level in the intentionally doped layers exceeds the solid solubility limit and the growth temperature is greater than 700 °C. Oxygen was not incorporated into the lattice for growth temperatures above 700 °C when using B2O3 as the source of boron, a Si growth rate for 0.5 nm s−1, and a B2O3 arrival rate of ∼2×1013 cm−2 s−1.
Raman scattering in InAs1−xSbx grown by organometallic vapor phase epitaxy
Authors: Cherng Y. T. , Ma K. Y. , Stringfellow G. B.
Published: July 2002

The first investigation of the lattice dynamics of the ternary alloy InAs1−xSbx has been made using Raman scattering. The InAs1−xSbx epilayers were grown by organometallic vapor phase epitaxy on (100) InAs and InSb substrates over the entire composition range. The spectra in the optical phonon frequency range show only one set of longitudinal- and transverse-optical (LO,TO) modes, which vary continuously with composition for x≤0.6, and two sets of LO modes for x>0.6. Both disorder-activated acoustic and optical phonon modes also appear.
Lack of temperature dependence of Fermi level pinning at the Cu/InP(110) interface: A comparison with Cu/GaAs and other systems
Authors: Cao Renyu , Miyano K. , Kendelewicz T. , Lindau I. , Spicer W. E.
Published: July 2002

Cu/GaAs(110) and Cu/InP(110) interfaces prepared at room temperature and 80 K low temperature have been studied using photoelectron spectroscopy. The temperature effect on the interface reactivity and the Fermi level pinning is quite different at these two interfaces despite the fact that the Cu overlayer morphology changes in the same way. For Cu/GaAs, the interfacial chemical reaction is suppressed at low temperature and the Fermi level pinning pattern varies significantly. In contrast, little change in the reaction for InP at low temperature, and consequently lack of temperature dependence of the Fermi level pinning is observed. The results provide insight into the Schottky barrier formation.
Interface growth with atoms and preformed clusters: Morphology and Schottky barrier variations for Au/InP(110)
Authors: Aldao C. M. , Vitomirov I. M. , Waddill G. D. , Weaver J. H.
Published: July 2002

With synchrotron radiation photoemission, we contrast the morphology and the Schottky barrier obtained when Au atoms are condensed onto InP(110) at 300 and ∼60 K to what is obtained when preformed, metallic Au clusters are deposited. Atom by atom deposition at either temperature leads to substrate disruption and Fermi level pinning 0.75 eV below the conduction-band minimum (CBM). Deposition of preformed Au clusters induces almost no disruption and a pinning position 0.42 eV below the CBM. Differences reflect the dependence upon the process, and therefore the energetics, of bringing dissimilar atoms in contact.
Growth of GaAs-Al-GaAs by migration-enhanced epitaxy
Authors: Tadayon Bijan , Tadayon Saied , Spencer M. G. , Harris G. L. , Rathbun L. , Bradshaw J. T. , Schaff W. J. , Tasker P. J. , Eastman L. F.
Published: July 2002

The GaAs-Al-GaAs structure is grown using migration-enhanced epitaxy (MEE) method at low temperature on a molecular beam epitaxy machine. With MEE the interdiffusion between Al and GaAs is reduced by a large amount, and the morphology is improved by a large degree. Still, Raman spectrum indicates poor crystallinity for the GaAs of the top layer. The effect of different annealing temperatures on the interdiffusion is also studied.
Kinetic model for gradual degradation in semiconductor lasers and light-emitting diodes
Authors: Khait Yu. L. , Salzman J. , Beserman R.
Published: July 2002

A new semiphenomenological statistical kinetic model for gradual degradation in semiconductor laser and light-emitting diodes is presented. In this model, the injection of a nonequilibrium electron-hole plasma increases the probability of structural changes and reduces their effective activation energy. Arrhenius-like expressions for the degradation rate with the pre-exponential factor and the effective activation energy as explicit functions of the material parameters are derived. Good agreement with experimental data is obtained.
Photoluminescence study on undoped single quantum well pseudomorphic structures
Authors: Kirby P. B. , Simpson M. B. , Wilcox J. D. , Smith R. S. , Kerr T. M. , Miller B. A. , Wood C. E. C.
Published: July 2002

In this letter, photoluminescence results obtained from two different undoped multilayered pseudomorphic structures grown by molecular beam epitaxy are compared. Intense and spectrally narrow emission was observed from both GaAs/InxGa1−xAs/GaAs and AlxGa1−xAs/InxGa1−xAs/GaAs structures. Excitonic emission from the quantum wells was confirmed by measurements of photoluminescence excitation spectra. The intensity and temperature dependences of the photoluminescence also revealed emission arising from bound excitons and impurities in the quantum wells. Intrinsic and extrinsic emission from confined levels was confirmed by the recorded photoluminescence excitation spectra along with intensity and temperature dependences. In the asymmetric AlxGa1−xAs/InxGa1−xAs/GaAs structure large changes were observed in the photoluminescence intensity under continuous optical excitation which are caused by the optical excitation of defects in the ternary AlxGa1−xAs on top of the pseudomorphically grown InxGa1−xAs.
Observation of optical field induced first-order electric Freedericksz transition and electric bistability in a parallel aligned nematic liquid-crystal film
Authors: Wu J. J. , Ong Gan-Sing , Chen Shu-Hsia
Published: July 2002

Optical field induced first-order electric Freedericksz transition and electric bistability in a homogeneously aligned nematic film is first observed. It is experimentally demonstrated that an applied optical field can transform the electric Freedericksz transition from second order to first order. The molecular reorientation as a function of electric field is then characterized by a hysteresis loop which exhibits the electric bistability. The results are in good agreement with theoretical predictions.
Short-wavelength (≲6400 Å) room-temperature continuous operation of p-n In0.5(AlxGa1−x)0.5P quantum well lasers
Authors: Dallesasse J. M. , Nam D. W. , Deppe D. G. , Holonyak N. , Fletcher R. M. , Kuo C. P. , Osentowski T. D. , Craford M. G.
Published: July 2002

Data are presented demonstrating short-wavelength (≲6400 Å) continuous (cw) laser operation of p-n diode In0.5(AlxGa1−x)0.5P multiple quantum well heterostructure (QWH) lasers grown lattice matched on GaAs substrates using metalorganic chemical vapor deposition. In the range from −30 °C to room temperature (RT≊300 K, λ≊6395 Å) the threshold current density changes from 2.3×103 A/cm2 (−30 °C) to 3.7×103 A/cm2 (RT, 300 K). The cw 300 K photopumped laser operation of the same quaternary QWH crystal is an order of magnitude lower in threshold (7×103 W/cm2, Jeq∼2.9×103 A/cm2) than previously reported for this crystal system, and agrees with the successful demonstration of cw 300 K laser diodes at this short wavelength.
Highly efficient second-harmonic generation of picosecond pulses at 1.32 μm in 3-methyl-4-nitropyridine-1-oxide
Authors: Josse D. , Hierle R. , Ledoux I. , Zyss J.
Published: July 2002

Second-harmonic generation was observed in a 7-mm-thick 3-methyl-4-nitropyridine-1-oxide crystal at the 1.32 and 1.34 μm emission lines of a Q-switched, mode-locked Nd3+:YAG laser, emitting short pulses of duration of 160 ps. A remarkably high effective conversion rate of 50% was measured by pump depletion in a type-I phase-matched configuration.
Superconductivity in thin films of Bi-Sr-Ca-Cu oxide deposited via laser ablation of oxide pellets
Authors: Jaggi N. K. , Meskoob M. , Wahid S. F. , Rollins C. J.
Published: July 2002

We have grown superconducting films on the technologically important sapphire substrates by CO2 pulsed laser ablation from fully superconducting targets of Bi2Sr3−xCaxCu2Oy followed by appropriate post-annealing. The composition of the films was found to deviate slightly from the target. Nevertheless, films with metallic resistivity decreasing between room temperature and 95 K, Tc(onset) of about 90 K and Tc(zero) of 72 K have been obtained. Magnetoresistance measurements in fields up to 12.85 T give a value of dHc2/dT of 1.6 T/K, which is intermediate between reported values of parallel and perpendicular Hc2 of fully aligned thin films. The implied partial orientation is consistent with the morphology seen by scanning electron microscopy.
Structure of silicon carbide precipitates in oxygen-implanted and annealed silicon-on-insulator material
Authors: Krause S. J. , Jung C. O. , Wilson S. R.
Published: July 2002

The structure of silicon carbide precipitates in oxygen-implanted and annealed silicon-on-insulator material was directly studied by high-resolution transmission electron microscopy. Epitaxially aligned precipitates 5–25 nm in size were located in the matrix silicon above and below the buried oxide layer with a density of 1×1010 cm−3. Precipitate-matrix interface strain was minimized by twinning and stacking fault formation in the precipitate and by amorphous silicon dioxide at the interface. The wide range of depths of the precipitates suggests that they are formed from trace amounts of carbon that are accelerated along with oxygen after mass analysis.
Photoemission study of the surface electronic structure of Bi-Ca-Sr-Cu-O superconductors modified by Ne sputtering, Ag deposition, and heat treatment
Authors: Lindberg P. A. P. , Shen Z.-X. , Lindau I. , Spicer W. E. , Eom C. B. , Geballe T. H.
Published: July 2002

Photoelectron spectroscopy has been utilized to study the effect on the electronic structure of the Bi-Ca-Sr-Cu-O surface of Ne sputtering, deposition of Ag, and annealing in ultrahigh vacuum, aiming at gaining insight into the role of different processing parameters. The results show that all these treatments significantly reduce the valency of Cu in the superconductor, and strongly modify the electronic states in the valence band. In addition, Ne sputtering or annealing in ultrahigh vacuum gives rise to new features in both the O 1s core-level data and in the valence band. We conclude that the electronic structure of the Bi-Ca-Sr-Cu-O surface is very sensitive to different methods of preparation.
Erase process in a direct-overwrite magneto-optic recording material
Authors: Schultz Mark , Kryder Mark
Published: July 2002

The erase process in a directly overwritable magneto-optical material is shown to be a domain collapse dominated process, not a reversed domain growth process as previously suggested. The results of two experiments which support this conclusion are described. The first is a static evaluation of the residual domains of unsuccessful erase attempts. The second is actual high-speed observation of the dynamic process itself. Both experiments show that erasure in this material results from collapse of the previously written domain.
Broadband all-fiber filters for wavelength division multiplexing application
Authors: Gonthier François , Lacroix Suzanne , Daxhelet Xavier , Black Richard J. , Bures Jacques
Published: July 2002

In-line spectral filters are designed and realized using the tapering technique to provide additional isolation to the demultiplexing fused fiber couplers. The typical performances obtained are less than 1 dB loss with more than 15 dB isolation in a 40 nm range around the desired wavelengths.