bluuebunny/crossref_metadata_2025 huggingface dataset:
Bayesian hierarchical approach to estimate insulin sensitivity by minimal model
Authors: AGBAJE Olorunsola F. , LUZIO Stephen D. , ALBARRAK Ahmed I. S. , LUNN David J. , OWENS David R. , HOVORKA Roman
Published: October 2003

We adopted Bayesian analysis in combination with hierarchical (population) modelling to estimate simultaneously population and individual insulin sensitivity (SI) and glucose effectiveness (SG) with the minimal model of glucose kinetics using data collected during insulin-modified intravenous glucose tolerance test (IVGTT) and made comparison with the standard non-linear regression analysis. After fasting overnight, subjects with newly presenting Type II diabetes according to World Health Organization criteria (n=65; 53 males, 12 females; age, 54±9 years; body mass index, 30.4±5.2 kg/m2; means±S.D.) underwent IVGTT consisting of a 0.3 g of glucose bolus/kg of body weight given at time zero for 2 min, followed by 0.05 unit of insulin/kg of body weight at 20 min. Bayesian inference was carried out using vague prior distributions and log-normal distributions to guarantee non-negativity and, thus, physiological plausibility of model parameters and associated credible intervals. Bayesian analysis gave estimates of SI in all subjects. Non-linear regression analysis failed in four cases, where Bayesian analysis-derived SI was located in the lower quartile and was estimated with lower precision. The population means of SI and SG provided by Bayesian analysis and non-linear regression were identical, but the interquartile range given by Bayesian analysis was tighter by approx. 20% for SI and by approx. 15% for SG. Individual insulin sensitivities estimated by the two methods were highly correlated (rS=0.98; P<0.001). However, the correlation in the lower 20% centile of the insulin-sensitivity range was significantly lower than the correlation in the upper 80% centile (rS=0.71 compared with rS=0.99; P<0.001). We conclude that the Bayesian hierarchical analysis is an appealing method to estimate SI and SG, as it avoids parameter estimation failures, and should be considered when investigating insulin-resistant subjects.
Angiotensinogen gene M235T polymorphism and reduction in wall thickness in response to antihypertensive treatment
Authors: BOZEC Erwan , FASSOT Céline , TROPEANO Anne-Isabelle , BOUTOUYRIE Pierre , JEUNEMAITRE Xavier , LACOLLEY Patrick , DABIRE Hubert , LAURENT Stéphane
Published: October 2003

The angiotensinogen M235T polymorphism has been linked to hypertension and cardiovascular disease. Carotid intima-media thickness (IMT) is an early marker of atherosclerosis. The objectives of the present study were to determine in previously untreated essential hypertensive patients whether carotid IMT was associated with the M235T polymorphism, and to determine whether the M235T polymorphism could influence the reduction of carotid IMT by antihypertensive treatment. Common carotid artery IMT was determined with a high-definition echotracking system in 98 previously untreated hypertensive patients in a cross-sectional study. A subgroup of 56 patients was included in a randomized double-blind parallel group study comparing the effect of the angiotensin-converting-enzyme-inhibitor enalapril with that of the β-blocker celiprolol during a 5 month period. In the cross-sectional study, a multivariate analysis showed that the M235T genotype was a significant independent determinant of carotid IMT, explaining 7% of the variance. Carotid IMT was higher in patients homozygous for the T allele than in MM patients. In the longitudinal study, the reduction in carotid IMT after antihypertensive treatment was significantly (P<0.01) higher in patients carrying the TT genotype than in patients carrying the MM genotype, despite similar reductions in blood pressure and independently of drug type. In conclusion, these data suggest that the angiotensinogen TT genotype at position 235 is a genetic marker for early carotid atherosclerosis in a hypertensive population and its regression under antihypertensive treatment.
Ketorolac attenuates cardiopulmonary derangements in sheep with combined burn and smoke inhalation injury
Authors: ENKHBAATAR Perenlei , MURAKAMI Kazunori , SHIMODA Katsumi , SALSBURY John , COX Robert , HAWKINS Hal , TRABER Lillian , HERNDON David , TRABER Daniel
Published: October 2003

Massive cutaneous burn combined with smoke inhalation causes high mortality in fire victims. Cyclo-oxygenase (COX) and inducible nitric oxide (NO) synthase (iNOS) have been shown to be up-regulated in burn injury. Ketorolac, a non-steroidal, anti-inflammatory agent (NSAID), inhibits prostaglandin and thromboxane synthesis through inhibition of COX. NSAIDs have been shown to down-regulate iNOS. Thus we hypothesized that treatment with ketorolac would attenuate burn/smoke-related cardiopulmonary derangements. We conducted a fully controlled long-term laboratory investigation in an Intensive Care Unit setting. Eighteen female sheep were surgically prepared for chronic study. After a recovery period of 5 days, a tracheotomy was performed under ketamine/halothane anaesthesia. Sheep were given a 40% total body surface third-degree burn and insufflated with cotton smoke (48 breaths, <40 °C). Sheep were divided into three groups: sham (not injured and not treated; n=6), control (injured, but not treated; n=6) and treated (injured and administered ketorolac 60 mg/day; n=6). The sham group had stable cardiopulmonary and systemic haemodynamics. Control animals showed depressed cardiopulmonary function, decreased pulmonary gas exchange, increased pulmonary microvascular leakage and decreased left ventricle stroke work index with elevated left atrial pressure. Systemic vascular leak in control animals was evidenced by robust haemoconcentration (haematocrit and fluid net balance). Treatment with ketorolac prevented all of these morbidities. Post-treatment with ketorolac also resulted in significant inhibition of elevated plasma nitrite/nitrate levels in control animals. These results suggest that ketorolac may ameliorate cardiopulmonary morbidity, at least in part, by inhibiting excessive NO.
Selective induction of human beta‐defensin mRNAs by Actinobacillus actinomycetemcomitans in primary and immortalized oral epithelial cells
Authors: Feucht E. C. , DeSanti C. L. , Weinberg A.
Published: October 2003

Human beta‐defensin‐2, and ‐3 (hBD‐2, ‐3) are small inducible antimicrobial peptides involved in host defense. Actinobacillus actinomycetemcomitans, a gram‐negative facultative anaerobe, is frequently associated with oral disease in humans. A. actinomycetemcomitans, strain JP2, was examined for its ability to modulate hBD‐2 and ‐3 gene expression in normal human oral epithelial cells (NHOECs) and in OKF6/Tert cells, an immortalized cell line derived from human oral epithelial cells. Stimulation of both cell types by live bacteria, at a minimal bacteria/cell ratio of 500 : 1, resulted in increased hBD‐3 gene expression. This was not evinced for hBD‐2 in either cell type with live bacteria, even at bacteria/cell ratios exceeding 500 : 1. The increased hBD‐3 gene expression was dependent upon viable bacteria, and not their lipopolysaccharides (LPS), since heat‐killed A. actinomycetemcomitans did not induce hBD‐3 transcript expression. The overall similarity between results obtained in OKF6/Tert cells and NHOECs suggest that the OKF6/Tert cell line may be a useful tool in the study of beta‐defensin expression in oral epithelium.
Susceptibility of oral bacteria to Melaleuca alternifolia (tea tree) oil in vitro
Authors: Hammer K. A. , Dry L. , Johnson M. , Michalak E. M. , Carson C. F. , Riley T. V.
Published: October 2003

The in vitro activity of Melaleuca alternifolia (tea tree) oil against 161 isolates of oral bacteria from 15 genera was determined. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) ranged from 0.003 to 2.0% (v/v). MIC90 values were 1.0% (v/v) for Actinomyces spp., Lactobacillus spp., Streptococcus mitis and Streptococcus sanguis, and 0.1% (v/v) for Prevotella spp. Isolates of Porphyromonas, Prevotella and Veillonella had the lowest MICs and MBCs, and isolates of Streptococcus, Fusobacterium and Lactobacillus had the highest. Time kill studies with Streptococcus mutans and Lactobacillus rhamnosus showed that treatment with ≥0.5% tea tree oil caused decreases in viability of >3 log colony forming units/ml after only 30 s, and viable organisms were not detected after 5 min. These studies indicate that a range of oral bacteria are susceptible to tea tree oil, suggesting that tea tree oil may be of use in oral healthcare products and in the maintenance of oral hygiene.
Agrobacterium tumefaciens mediated transformation of the oomycete plant pathogen Phytophthora infestans
Authors: Vijn Irma , Govers Francine
Published: October 2003

Agrobacterium tumefaciens is widely used for plant DNA transformation and, more recently, has also been used to transform yeast and filamentous fungi. Here we present a protocol for Agrobacterium‐mediated DNA transformation of the oomycete Phytophthora infestans, the causal agent of potato late blight. Binary T‐DNA vectors containing neomycin phosphotransferase (npt) and β‐glucuronidase (gus) fused to oomycete transcriptional regulatory sequences were constructed. Seven days of co‐cultivation followed by transfer to a selective medium containing cefotaxim to kill Agrobacterium and geneticin to select for transformants, resulted in geneticin resistant colonies. Under optimal conditions with Agrobacterium supplemented with a ternary plasmid carrying a constitutive virG gene and in the presence of acetosyringone as inducer, up to 30 transformants per 107 zoospores could be obtained. The majority of these transformants contained a single T‐DNA copy randomly integrated at a chromosomal locus. Using a similar protocol, geneticin resistant transformants of two other oomycetes species were obtained, Phytophthora palmivora and Pythium ultimum.
Active defence responses associated with non‐host resistance of Arabidopsis thaliana to the oomycete pathogen Phytophthora infestans
Authors: Huitema Edgar , Vleeshouwers Vivianne G. A. A. , Francis David M. , Kamoun Sophien
Published: October 2003

The molecular basis of non‐host resistance, or species‐specific resistance, remains one of the major unknowns in the study of plant–microbe interactions. In this paper, we describe the characterization of a non‐host pathosystem involving the model plant Arabidopsis thaliana and the economically important and destructive oomycete pathogen Phytophthora infestans. Cytological investigations into the early stages of this interaction revealed the germination of P. infestans cysts on Arabidopsis leaves, direct penetration of epidermal cells, formation of infection vesicles and occasionally secondary hyphae, followed by a typical hypersensitive response. P. infestans biomass dynamics during infection of Arabidopsis was monitored using kinetic PCR, revealing an increase in biomass during the first 24 h after inoculation, followed by a decrease in the later stages. Transgenic reporter lines and RNA blot analyses were used to characterize the defence responses induced following P. infestans infection. Significant induction of PDF1.2 was observed at 48 h after inoculation, whereas elevated levels of PR gene expression were detected three days after inoculation. To further characterize this defence response, DNA microarray analyses were carried out to determine the expression profiles for c. 11 000 Arabidopsis cDNAs 16 h after infection. These analyses revealed a significant overlap between Arabidopsis non‐host response and other defence‐related treatments described in the literature. In particular, non‐host response to P. infestans was clearly associated with activation of the jasmonate pathway. The described Arabidopsis–P. infestans pathosystem offers excellent prospects for improving our understanding of non‐host resistance.
Dietary cholic acid lowers plasma levels of mouse and human apolipoprotein A‐I primarily via a transcriptional mechanism
Authors: Srivastava Rai Ajit K. , Srivastava Neelam , Averna Maurizio
Published: October 2003

To induce dietary atherosclerosis in mice, high‐fat/high‐cholesterol (HF) diets are frequently supplemented with cholic acid (CA). This diet produces low plasma levels of high‐density lipoprotein (HDL) and high levels of low‐density lipoprotein (LDL). However, HF diets without any added CA, which more closely resemble human diets, increase levels of both HDL and LDL, suggesting that CA may be responsible for the lowering of HDL. Our aim was to examine the potential mechanism responsible for the lowering of HDL. Nontransgenic (NTg) C57BL mice and apoA‐I‐transgenic (apoAI‐Tg) mice, with greatly increased basal apoA‐I and HDL levels, were used. Mice were fed the following four diets: control (C), high‐fat/high‐cholesterol (HF), control and 1% cholate (CA) and HF + CA. Dietary CA reduced plasma HDL levels by 35% in NTg and 250% in apoAI‐Tg mice, independent of the fat or cholesterol content of the diet. Hepatic apoA‐I mRNA decreased 30% in NTg and 180% in apoAI‐Tg mice. Hepatic apoA‐I synthesis and apoA‐I mRNA transcription rates also decreased in parallel with apoA‐I mRNA levels, suggesting that the CA‐induced decreases in plasma apoA‐I levels occurred primarily via decreasing apoA‐I mRNA transcription rates. An HF diet increased HDL levels 1.8‐fold in NTg and 1.5‐fold in apoAI‐Tg mice. Addition of CA to the HF diet lowered HDL levels by 1.6‐fold in NTg and 2.5‐fold in apoAI‐Tg mice. Transfection studies with the apoA‐I promoter suggested the presence of a putative cis‐acting element responsible for the CA‐mediated down‐regulation of the apoA‐I promoter activity. Measurements of apoA‐I regulatory protein‐1 (ARP‐1) mRNA, a negative regulator of the apoA‐I gene in the mouse liver showed that CA increased the ARP‐1 mRNA levels. Because apoA‐I gene transcription alone was not sufficient to account for the lowering of plasma HDL levels, scavenger receptor‐B1 (SR‐B1) and hepatic lipase (HL) mRNAs levels were quantitated. The levels of SR‐B1 and HL mRNA were not changed by dietary CA. These studies suggest that dietary cholate regulates plasma levels of apoA‐I primarily by a transcriptional mechanism via a putative bile acid response element involving a negative regulator of apoA‐I, and partly by an unidentified post‐transcriptional mechanism.
The evolutionarily conserved porcupine gene family is involved in the processing of the Wnt family
Authors: Tanaka Kimiko , Okabayashi Koji , Asashima Makoto , Perrimon Norbert , Kadowaki Tatsuhiko
Published: October 2003

The Drosophila segment polarity gene product Porcupine (Porc) was first identified as being necessary for processing Wingless (Wg), a Drosophila Wnt (Wnt) family member. Mouse and Xenopus homologs of porc (Mporc and Xporc) were identified and found to encode endoplasmic reticulum (ER) proteins with multiple transmembrane domains. In contrast with porc, four different types of Mporc and Xporc mRNA (A–D) are generated from a single gene by alternative splicing. Mporc mRNA is differentially expressed during embryogenesis and in various adult tissues, demonstrating that the alternative splicing is regulated to synthesize the specific types of Mporc. In transfected mammalian cells, all Mporc types affect the processing of mouse Wnt 1, 3A, 4, 6, and 7B but not 5A. Furthermore, all Mporc types are co‐immunoprecipitated with various Wnt proteins. These results suggest that Mporc may function as a chaperone‐like molecule for Wnt. Interestingly, all Mporc types can substitute for Porc, as they are able to rescue the phenotypes of Drosophila porc embryos. Consistent with this observation, Mporc, like Porc, modifies the processing of Wg expressed in mammalian cells. These results demonstrate that the porc gene family encodes the multitransmembrane ER proteins, which are evolutionarily well conserved and involved in processing the Wnt family.
Diverse microbial communities inhabiting ferromanganese deposits in Lechuguilla and Spider Caves
Authors: Northup Diana E. , Barns Susan M. , Yu Laura E. , Spilde Michael N. , Schelble Rachel T. , Dano Kathleen E. , Crossey Laura J. , Connolly Cynthia A. , Boston Penelope J. , Natvig Donald O. , Dahm Clifford N.
Published: October 2003

Lechuguilla Cave is an ancient, deep, oligotrophic subterranean environment that contains an abundance of low‐density ferromanganese deposits, the origin of which is uncertain. To assess the possibility that biotic factors may be involved in the production of these deposits and to investigate the nature of the microbial community in these materials, we carried out culture‐independent, small subunit ribosomal RNA (SSU rRNA) sequence‐based studies from two sites and from manganese and iron enrichment cultures inoculated with ferromanganese deposits from Lechuguilla and Spider Caves. Sequence analysis showed the presence of some organisms whose closest relatives are known iron‐ and manganese‐oxidizing/reducing bacteria, including Hyphomicrobium, Pedomicrobium, Leptospirillum, Stenotrophomonas and Pantoea. The dominant clone types in one site grouped with mesophilic Archaea in both the Crenarchaeota and Euryarchaeota. The second site was dominated almost entirely by lactobacilli. Other clone sequences were most closely related to those of nitrite‐oxidizing bacteria, nitrogen‐fixing bacteria, actinomycetes and β‐ and γ‐Proteobacteria. Geochemical analyses showed a fourfold enrichment of oxidized iron and manganese from bedrock to darkest ferromanganese deposits. These data support our hypothesis that microorganisms may contribute to the formation of manganese and iron oxide‐rich deposits and a diverse microbial community is present in these unusual secondary mineral formations.
Dissecting cellulitis of the scalp with associated spondylarthropathy: case report and review
Authors: Salim A , David J , Holder J
Published: October 2003

Arthritis is a well‐recognized but uncommon accompaniment to several chronic cutaneous inflammatory conditions in which severe acne is one component. We report the case of a man with dissecting cellulitis of the scalp who developed severe peripheral and axial arthritis.
Job's syndrome – a case report
Authors: Verma S , Wollina U
Published: October 2003

Job's syndrome is a rare immune disorder characterized by atopic dermatitis‐like skin lesions, elevated serum IgE‐levels, repeated occurrence of skin and respiratory tract infections, and skeletal abnormalities. We report on a 12‐year‐old boy with Job's syndrome from Gujarat State, India. He disclosed the characteristic face, eczematous skin reactions and skin and lung infections. Long‐term chemoprophylaxis was realized with oral penicillins that dramatically improved the course of his disease. Other treatment options are discussed but not all meet the needs of developing countries.
Undifferentiated connective tissue disease and its cutaneous manifestations
Authors: Pestelli E , Volpi W , Giomi B , Caproni M , Fabbri P
Published: October 2003

Undifferentiated connective tissue disease (UCTD, also named UCT syndrome, latent lupus or incomplete lupus) is regarded as an autoimmune disorder in which signs and symptoms are widely variable and evocative for connectivitis but not sufficiently evolved to fulfil any of the accepted classification criteria for the defined connective tissue diseases. In this paper we describe the case of a 47‐year‐old woman affected by UCTD according to the preliminary classification criteria supplied by Mosca et al. in 1999.
A new surgical approach for the treatment of severe epithelial skin sun‐induced damage
Authors: Pianigiani E , Cherubini Di Simplicio F , Ierardi F , Taddeucci P , Andreassi A , Fimiani M
Published: October 2003

Background  Cutaneous photoageing is a complex biological process affecting all layers of the skin. Skin damage resulting from intrinsic ageing and extrinsic photoageing may trigger skin cancer. In patients with advanced photoageing and/or diffuse actinic damage, local therapy is often inadequate and the possibility of combined therapy needs to be assessed.

Subjects  Here we report three cases of patients over 75 years of age with advanced diffuse epithelial skin damage of photoexposed areas consisting of several superficial actinic keratoses, ipermelanotic lesions and multiple skin cancers.

Methods  Neoplastic lesions and damaged skin were removed by superficial erbium laser ablation and the epidermis reconstructed with autologous epidermal sheets expanded in vitro from healthy cells obtained from unexposed areas of the body.

Results  Our initial studies show that this procedure is very effective in the short term for treating and preventing the UV‐induced skin cancer and precancerous lesions, and also suggest good long‐term control of the disease with very interesting aesthetic results.
Langerhans’ cell histiocytosis and haemophagocytic lymphohistiocytosis in an elderly patient
Authors: Ioannidou D , Krasagakis K , Panayiotidis J , Stefanidou M , Alexandrakis M , Tosca A
Published: October 2003

We present a case of a 78‐year‐old man suffering from a chronic psoriasiform eruption, with rapid deterioration over the previous 8 weeks. Langerhans’ cell histiocytosis with skin and bone involvement was diagnosed, and there was evidence of liver and lung dysfunction. The patient was treated with prednisolone and etoposide, and initially experienced a partial improvement. Three weeks later, haemophagocytic lymphohistiocytosis and subsequently a large pulmonary abscess with sepsis attributed to opportunistic gram‐negative enterobacteriaceae Serratia marcescens developed, and the patient died. The present case of Langerhans’ cell histiocytosis is of particular interest because of the previously unreported development of haemophagocytic lymphohistiocytosis in the elderly population.
Comparative population dynamics of Eucalyptus cladocalyx in its native habitat and as an invasive species in an urban bushland in south‐western Australia
Authors: Ruthrof Katinka X. , Loneragan William A. , Yates Colin J.
Published: October 2003

Abstract.  Eucalyptus cladocalyx F. Muell., is a tree with a restricted distribution in the Southern Flinders Ranges, South Australia. It was originally introduced into the urban bushland of Kings Park, Perth, Western Australia in 1932 as an ornamental. Since its planting, E. cladocalyx has become invasive, spreading into the bushland up to 70 m away from planting sites. Anecdotal evidence suggests that the E. cladocalyx population is increasing at a greater rate than the two principal native tree species, E. gomphocephala DC. and E. marginata Donn ex Smith, but little is known about the factors influencing its invasion, or its biology. This study describes the population structure of E. cladocalyx, E. gomphocephala and E. marginata in Kings Park and the role of fire in the recruitment process. The study indicated that the three species have characteristics common to temperate Eucalyptus species that mass recruit seedlings following fire, with high numbers of seedlings found in recently burnt areas and low numbers in unburnt areas. Seedling survival in E. cladocalyx was higher than either of the native species. Furthermore, E. cladocalyx adults showed higher rates of canopy recovery following fires. It is argued that although fire in Kings Park is providing opportunities for E. cladocalyx, E. gomphocephala and E. marginata recruitment, the E. cladocalyx population is more resilient in an environment frequently disturbed by fire compared with the native populations.
Age, Vascular Risk, and Cognitive Decline in an Older, British, African‐Caribbean Population
Authors: Stewart Robert , Prince Martin , Mann Anthony
Published: October 2003

Objectives: To investigate associations between baseline factors and subsequent cognitive decline in an older African‐Caribbean population.

Design: Three‐year follow‐up of a community sample.

Setting: Registration lists for seven primary care services in south London, United Kingdom.

Participants: Of 290 Caribbean‐born people aged 55 to 75 recruited at baseline, 216 (75%) were reinterviewed after a 3‐year period. Sufficient data for analysis were present for 207.

Measurements: Tests of verbal memory (immediate and delayed), orientation, and attention were administered at baseline and at 3 years. A composite measure of cognitive change was derived through factor analysis. Participants in the lowest quintile were defined as having cognitive decline and were compared with the rest of the sample with respect to baseline characteristics.

Results: Cognitive decline was strongly associated with increased age, but not with sex, education, or occupation. It was also not directly associated with hypertension, diabetes mellitus, or exercise, but the age‐decline association was significantly stronger in people with diabetes mellitus and was lower in those reporting vigorous physical exercise at baseline. When cognitive decline was investigated separately for individual tests, both these patterns of association were particularly strong for decline in delayed verbal recall.

Conclusion: The association between increased age and cognitive decline, particularly decline in verbal recall, was stronger in people with diabetes mellitus (but not hypertension) and weaker in people who were more physically active.
Treatment of Elderly and Other Adult Patients for Depression in Primary Care
Authors: Fischer Lucy Rose , Wei Feifei , Solberg Leif I. , Rush William A. , Heinrich Richard L.
Published: October 2003

Objectives:To determine whether depression is treated differently in older and younger patients in primary care clinics.

Design:Administrative data were used to identify patients with a depression diagnosis code. The sources of data were baseline and 3‐month follow‐up surveys, the health plan electronic database, and chart audits.

Setting:Nine primary care clinics owned by a health maintenance organization in the Midwest.

Participants:The study sample (N=1,023) consisted of adult patients, aged 19 to 93, and was divided into six age groups, from young adult, under age 35, to old old, 75 or older.

Measurements:Independent variables were a series of dummy variables: age groups, baseline depression severity, sex, and incident depression. Outcomes were defined as care processes (assessment, resources) and improvement in depression symptoms (Center for Epidemiologic Studies—Depression scale short form). Univariate and multivariate logistic regression analyses were used to analyze patient characteristics, depression symptoms, and care process variables. Significance level was reported based on the chi‐square test of probability,P≤.05.

Results:The adjusted response rates to the baseline and follow‐up surveys were 69% and 82%. Elderly depressed patients were more likely than younger depressed patients to be widowed, have low levels of education, have fair or poor health, and have three or more comorbid health problems. There were no differences, by age, in number of depressive symptoms, antidepressant treatment, or recommendation for a follow‐up appointment. Younger patients were more likely than older patients to have a new diagnosis of depression and to report being depressed most of the past year. Providers were only 6% as likely to ask old‐old depressed patients about suicide risk, about one‐fourth as likely to referral them to a mental health therapist, about one‐fifth as likely to ask if they felt depressed, and one‐twentieth as likely to ask about a problem with alcohol as they were with young‐adult depressed patients. The old‐old were about one‐third as likely to report improvement in depression symptoms after 3 months as the young‐adult patients.

Conclusion:This study suggests a possible pattern of underattention to the oldest depressed patients. Failure to ask about suicide risk is especially of concern because of the high suicide rate of depressed geriatric patients. The finding that physicians are less likely to focus on depression with old‐old patients may be explained, in part, by the concept of invisibility of the ordinary.
Influence of Executive Function on Locomotor Function: Divided Attention Increases Gait Variability in Alzheimer's Disease
Authors: Sheridan Pamela L. , Solomont Judi , Kowall Neil , Hausdorff Jeffrey M.
Published: October 2003

Objectives: To evaluate how cognitive function and divided attention affect gait in Alzheimer's disease (AD).

Design: Cross‐sectional intervention study with subjects serving as their own controls.

Setting: Inpatient unit and outpatient clinic for patients with dementia located at a Veterans Affairs Medical Center.

Participants: Twenty‐eight patients diagnosed with probable AD.

Intervention: Performance of a cognitive task (repeating random digits) while walking.

Measurements: Neuropsychological measures includ‐ing clock drawing, verbal fluency, and digit span were obtained along with the Clinical Dementia Rating and Mini‐Mental State Examination, the measures of dementia severity. Gait speed and stride‐to‐stride variability of gait rhythm were measured, once during normal walking and once during dual‐task walking.

Results: During usual walking, subjects walked slowly and with greater gait variability than older adults without AD. Gait speed was significantly reduced (P<.012) and gait variability increased with dual‐task walking (P<.007). The effect on gait variability was larger than the effect on gait speed (P<.015). Executive and neuropsychological function were significantly (P<.02) associated with the increased gait variability that occurred when walking with divided attention but not with gait speed or usual, single‐task walking measures of gait.

Conclusion: Divided attention markedly impairs the ability of patients with AD to regulate the stride‐to‐stride variations in gait timing. This susceptibility to distraction and its effect on stride time variability, a measure of gait unsteadiness, could partially explain the predilection to falling observed in patients with dementia. The results also support the concept that persons with AD have significant impairments in the cognitive domain of attention and that locomotor function relies upon cognitive, especially executive, function.
Differing Risk Factors for Falls in Nursing Home and Intermediate‐Care Residents Who Can and Cannot Stand Unaided
Authors: Lord Stephen R. , March Lynn M. , Cameron Ian D. , Cumming Robert G. , Schwarz Jennifer , Zochling Jane , Chen Jian Sheng (Charles) , Makaroff Jan , Sitoh Yih Yiow , Lau Tang Ching , Brnabic Alan , Sambrook Philip N.
Published: October 2003

Objectives: To determine fall risk factors in nursing home and intermediate‐care residents who can and cannot stand unaided.

Design: Prospective cohort study.

Setting: Residential elderly care facilities in Sydney, Australia.

Participants: One thousand people aged 65 to 103 (mean age ± standard deviation: 85.0 ± 7.4).

Measurements: Accidental falls.

Results: Fall rates were highest in those with fair standing balance, intermediate in those with the best standing balance, and lowest in those with the worst standing balance. This nonlinear pattern was even more striking when subjects were categorized according to their standing balance and ability to rise from a chair. Using this dual classification, fall rates were highest in those who could rise from a chair but could not stand unaided (81%) and lowest in those who could neither rise from a chair nor stand unaided (48%). In residents who could stand unaided, risk factors included increased age, male sex, higher care classifications, incontinence, psychoactive medication use, previous falls, and slow reaction times. In contrast, quite different risk factors were evident in residents who could not stand unaided, with a number of known fall risk factors (previous stroke, reduced ability to rise from a chair, slow reaction times) being associated with fewer falls. In this group, risk factors were intermediate versus nursing home care, poor health status, psychoactive medication use, Parkinson's disease, previous falls, and being able to get out of a chair.

Conclusion: The findings indicate that there are different risk factors for falls for people living in residential aged care facilities who can and cannot stand unaided. These findings provide important information for developing fall‐prevention strategies and suggest that those who can stand unaided but have multiple falls risk factors constitute the highest priority group for such interventions.
Behavioral and infectious disease risks in young blood donors: implications for recruitment
Authors: Damesyn Mark A. , Glynn Simone A. , Schreiber George B. , Ownby Helen E. , Bethel James , Fridey Joy , McMullen Quentin , Garratty George , Busch Michael P.
Published: October 2003

BACKGROUND:  Recruitment of young donors is critical to expand the donor base and sustain the blood supply. Nevertheless, there is concern that younger blood donors may have a higher risk profile than their older counterparts.

STUDY DESIGN AND METHODS:  The prevalence of behavioral risks associated with transfusion‐transmissible viral infections and the incidence of viral markers were compared between younger and older donors. Behavioral risks included unreported deferrable risks (UDRs) and HIV test seeking estimated from anonymous donor surveys administered in 1993 and 1998. The incidence of HIV, HCV, or HBV was estimated from donors giving at five US blood centers between 1996 and 2000.

RESULTS:  Donors younger than 25 years of age were significantly more likely to report a UDR or HIV test seeking than those 25 years or older. ORs comparing donors 18 to 19 and 20 to 24 years of age to those 25 years or older were 2.0 (95% CI, 1.5‐2.6) and 1.5 (95% CI, 1.2‐1.9) for UDR and 4.5 (95% CI, 3.0‐6.9) and 5.5 (95% CI, 4.2‐7.1) for test seeking, respectively. Although incidence estimates did not significantly differ between age groups, HIV incidence appeared to be highest in 18‐ to 19‐year‐old donors, whereas HBV incidence was highest in 20‐ to 24‐year‐old donors.

CONCLUSIONS:  Donors younger than 25 years of age appeared to have a higher behavioral risk profile than older donors. The message not to donate when a behavioral risk is present or for obtaining HIV tests needs to be reinforced in younger donors.
Laser‐assisted optical rotational cell analyzer measurements reveal early changes in human RBC deformability induced by photodynamic treatment
Authors: Hardeman Max R. , Besselink Geert A.J. , Ebbing Iwan , De Korte Dirk , Ince Can , Verhoeven Arthur J.
Published: October 2003

BACKGROUND:  The ability to deform is important for circulating RBCs in vivo, and earlier studies showed that this property can objectively be measured in vitro by the LORCA. In this study it was investigated whether photodynamic treatment of human RBCs (meant to inactivate contaminating pathogens) affects deformability.

STUDY DESIGN AND METHODS:  WBC‐reduced RBC suspensions (30% Hct) were treated with 1,9‐dimethylmethylene blue (DMMB) and red light. Changes in deformability were analyzed by LORCA measurements, in which elongation of the cells is measured at increasing shear stress. The effect of DMMB concentration and light dose was determined as well as the interfering effect of two scavengers of reactive oxygen species, that is, dipyridamole and Trolox.

RESULTS:  Photodynamic treatment with DMMB resulted in clear changes in RBC deformability. Deformability changes occurred before onset of hemolysis. Under relatively mild treatment conditions, especially deformability at low shear stress was decreased, whereas deformability changes at high shear stress only occurred under harsher treatment conditions. Inclusion of dipyridamole and/or Trolox primarily prevented deformability changes at high shear stress.

CONCLUSION:  LORCA measurements can effectively be used to detect changes in deformability that are induced by photodynamic treatment of human RBCs. A change in deformability represents an early marker of RBC damage under these conditions.
A theoretical study of the reaction of O(3P) with an allyl radical C3H5
Authors: Park Jong-Ho , Lee Hohjai , Choi Jong-Ho
Published: October 2003

Ab initio calculations of the reaction of ground-state atomic oxygen [O(3P)] with an allyl radical (C3H5) have been carried out using the density functional method and the complete basis set model. On the calculated lowest doublet potential energy surface, the barrierless association of O(3P) to C3H5 forms three energy-rich addition intermediates, which are predicted to undergo subsequent isomerization and decomposition steps leading to various products: C3H4O+H, CH2O+C2H3, C2H4+CHO, C2H2O+CH3, C2H5+CO, C3H4+OH, and C2H4O+CH. The respective reaction mechanisms through the three addition intermediates are presented, and it has been found that the barrier height, reaction enthalpy, and the number of intermediates involved along the reaction coordinate are of extreme importance in understanding such reactive scattering processes. With the aid of Rice–Ramsperger–Kassel–Marcus calculations, the major reaction pathway is predicted to be the formation of acrolein (C3H4O)+H, which is consistent with the previous gas-phase bulk kinetic experiment performed by Gutman et al. [J. Phys. Chem. 94, 3652 (1990)]. For the minor C3H4+OH channel, which has been newly found in the recent crossed beam investigations, a second barrierless, direct H-atom abstraction from the central carbon of C3H5 is calculated to compete with the addition process due to the little C–H bond dissociation energy and the formation of a stable allene product. The dynamic and kinetic characteristics of the reaction mechanism are discussed on the basis of the comparison of prior statistical calculations to the nascent internal distributions of the observed OH product.
Molecular structure and hydrophobic solvation thermodynamics at an octane–water interface
Authors: Patel Harshit A. , Nauman E. Bruce , Garde Shekhar
Published: October 2003

We present results from atomically detailed molecular dynamics simulation of an octane–water liquid–liquid interface. We specifically focus on water structure, orientation, coordination numbers, and hydrogen bonding at the interface. In addition, we probe the interface through insertions of different nonpolar solutes at various locations in the system. Several interesting details of the interface emerge from our calculations. We find that the number density profiles of both water and octane vary monotonically through the interface in a sigmoidal fashion over approximately 1 nm 1-99 interfacial width. Interestingly, the overall heavy-atom density profile shows a distinct minimum in the interfacial region that reflects the hydrophobic nature of the hydration at the octane–water interface. Furthermore, calculations of excess chemical potentials of attractive Lennard-Jones and purely repulsive hydrophobic solutes display an interfacial minimum, indicating the relative ease of cavity formation at the interface. The inhomogeneous nature of the interface affects the water structure and hydrogen-bonding properties at the interface. We find that water coordination number as well as the number of hydrogen bonds water molecules make with their neighbors decreases through the interface as we move from bulk water to the octane phase. As a result, we find populations of water with low coordination numbers, including monomeric water species in the interfacial region. Although the number of hydrogen bonds per water is low in the interfacial region, a larger fraction of coordination waters is hydrogen bonded to the central water in the interfacial region.
Time-dependent remanent coercivity in nanosecond switching in perpendicular media
Authors: Misra Arkajyoti , Visscher P. B. , Apalkov D. M.
Published: October 2003

We have simulated the time-dependent remanent coercivity of a perpendicular medium. The material parameters have been chosen to be consistent with the data from quasistatic magnetometry measurements on CoCrPt, and the pulse properties were obtained from stripline experiments. Our remanent coercivity results confirm the rise in coercivity at short times which had been found experimentally. We have also found a counterintuitive increase of coercive field with decreasing initial remanent magnetization—a partially switched sample requires a stronger reverse field for complete reversal.
Positron–electron autocorrelation function study of E-center in silicon
Authors: Ho K. F. , Ching H. M. , Beling C. D. , Fung S. , Ng K. P. , Biasini M. , Ferro G. , Gong M.
Published: October 2003

Two-dimensional angular correlation of annihilation radiation (2D-ACAR) spectra have been taken for 1019 cm−3 phosphorus-doped Si in the as-grown state after having been subjected to 1.8 MeV electron fluences of 1×1018 and 2×1018 cm−2. Positron annihilation lifetime spectroscopy confirms, in accordance with previous works, that positrons are saturation trapping into (VSi:P) pair defect (E-center) monovacancy sites in the electron irradiated samples. In the as-grown case, the positron–electron autocorrelation functions along the [111] and [1-10] directions, obtained through Fourier transformation of the 2D-ACAR data, reveal zero-crossings that deviate only slightly from the lattice points, in a manner consistent with positron–electron correlation effects. Conversely, in the spectra of the irradiated samples, the zero-crossing points are observed to move outward further by between 0.15 and 0.50 Å. This displacement is associated with positron annihilation with electrons in localized orbitals at the defect site. An attempt is made to extract just the component of the defect’s positron–electron autocorrelation function that relates to the localized defect orbitals. In doing this features are found that correspond to the expected atomic positions at the vacancy defect site suggesting that this real-space function may provide a convenient means for obtaining a mapping of localized orbitals. The observed approximate separability of positron and electron wave-function autocorrelates leads to an estimate of 0.22 eV for the positron binding energy to the E-center.
Formation of droplets on nonvolatile soluble particles
Authors: Talanquer V. , Oxtoby D. W.
Published: October 2003

Density functional theory is used to analyze the stability and structural properties of droplets formed by the condensation of a volatile solvent on a soluble fluid particle composed of a fixed number of molecules of a second species with extremely low volatility. Interaction parameters between the species are chosen to ensure that the soluble particle is completely wetted by the solvent. We study the properties of miscible and partially miscible mixtures. Droplets with a partially soluble core may exhibit a solubility transition at a vapor pressure above the vapor pressure of the bulk saturated solution. This transition resembles deliquescence in water soluble salts, but exhibits distinctive features. The soluble particle dissolves spontaneously at a well defined value of the supersaturation and the relative change in the droplet’s size at the transition is greater for the smaller particles. Comparisons of our results with the predictions of Köhler theory of activation show that the capillarity approximation overestimates the vapor pressure of the droplets, particularly in small systems.
Intramolecular solvation effects in the SN2 reaction Cl−+Cl(CH2)nCN
Authors: Pagliai Marco , Raugei Simone , Cardini Gianni , Schettino Vincenzo
Published: October 2003

The chemical reactions Cl−+Cl(CH2)nCN (n=2–5) have been studied with ab initio molecular dynamics. The effects of the cyano group on the energy profile of the reactions as the length of the alkilic chain increases have been discussed in terms of electrostatics of the systems. The thermal effects have been computed in the Blue Moon Ensemble showing a large influence on the energy barriers. It has been shown that six membered hydrogen-bonded pre-reactive complexes are stable even at room temperature. The results of the simulation allow for an explanation for the increased reactivity of these systems compared to the parent Cl−+Cl(CH2)nCH3 reactions.
Structural peculiarities of quench-condensed pure and argon-doped nitrous oxide
Authors: Solodovnik A. A. , Danchuk V. V.
Published: October 2003

Electron diffraction studies are carried out for condensed N2O and N2O–Ar films. Deposition is done at substrate temperatures of 10 and 20 K. The growth process of N2O deposits is studied. A strong effect of argon impurities on the structure of the nitrous oxide matrix is observed. The phase separation of the solutions is studied. The equilibrium solubility of argon atoms in nitrous oxide is very low. Introduction of a small amount of argon impurity into the molecular lattice destroys the crystal structure. An effect of the size of the sample on its structure is also studied.
The double exchange mechanism revisited: An ab initio study of the [Ni2(napy)4Br2]+ complex
Authors: Guihéry Nathalie , Malrieu Jean Paul
Published: October 2003

The results of extensive ab initio configuration interaction (CI) calculations of the spectrum of the [Ni2(napy)4Br2]+ complex are reported and analyzed. This complex can be seen as the simplest system exhibiting the so-called double-exchange phenomenon. This effect is usually rationalized in the minimal valence space defined by the partially occupied orbitals. The analysis reveals that the leading antiferromagnetic contributions implies the atomic excited (non-Hund) states through a mechanism proposed by Anderson et al. and Blondin et al. but the energy spacings deviate significantly from those predicted by the usually accepted model Hamiltonian. An analytic derivation explains these deviations and an alternative modelization of the spectrum is proposed. The extensive CI calculations also reveal the existence of another mechanism involving low-lying virtual orbitals with a large component on the 4s of the Ni atoms and that strongly stabilizes the upper excited states.
Magnetic properties of parabolic quantum dots in the presence of the spin–orbit interaction
Authors: Voskoboynikov O. , Bauga O. , Lee C. P. , Tretyak O.
Published: October 2003

We present a theoretical study of the effect of the spin–orbit interaction on the electron magnetization and magnetic susceptibility of small semiconductor quantum dots. Those characteristics demonstrate quite interesting behavior at low temperature. The abrupt changes of the magnetization and susceptibility at low magnetic fields are attributed to the alternative crossing between the spin–split electron levels in the energy spectrum, essentially due to the spin–orbit interaction (an analog of the general Paschen–Back effect). Detailed calculation using parameters of InAs semiconductor quantum dot demonstrates an enhancement of paramagnetism of the dots. There is an additional possibility to control the effect by external electric fields or the dot design.
Hexaferrite–FeCo nanocomposite particles and their electrical and magnetic properties at high frequencies
Authors: Sudakar C. , Subbanna G. N. , Kutty T. R. N.
Published: October 2003

Nanocomposites are realized by chemical reduction whereby the conducting magnetic particles of Fe–Co alloy are generated within the insulating ferrimagnetic BaCo2Fe16O27 or Ba2Co2Fe12O22 hexaferrite matrix. Transmission electron microscopy revealed that metal nanoparticles precipitate coherently as thin flakes along the a–b planes of the derivative magnetoplumbite lattice of the hexaferrites above the characteristic reduction temperature, TR>375 °C in H2 atmosphere. The coercivity increases with TR in the early stages of the solid-state precipitation and then decreases with the formation of larger fractions of Fe–Co alloy; a converse trend is noticed for magnetization. The complex permittivity increases with reduction to ∼50 in the broad frequency range of 4–18 GHz. The complex permeability is also enhanced with the content of Fe–Co nanoparticles. It is proposed that the spin reorientation at the Fe–Co/hexaferrite interface gives rise to broadband response, rendering these composite particles useful as electromagnetic microwave absorbers.