High-fidelity scaling relationships for determining dissipative particle dynamics parameters from atomistic molecular dynamics simulations of polymeric liquids.

An optimized Dissipative Particle Dynamics (DPD) model with simple scaling rules was developed for simulating entangled linear polyethylene melts. The scaling method, which can be used for mapping dimensionless (reduced units) DPD simulation data to physical units, was based on scaling factors for three fundamental physical units; namely, length, time, and viscosity. The scaling factors were obtained as ratios of equilibrium Molecular Dynamics (MD) simulation data in physical units and equivalent DPD simulation data for relevant quantities. Specifically, the time scaling factor was determined as the ratio of longest relaxation times, the length scaling factor was obtained as the ratio of the equilibrium end-to-end distances, and the viscosity scaling factor was calculated as the ratio of zero-shear viscosities, each as obtained from the MD (in physical units) and DPD (reduced units) simulations. The scaling method was verified for three MD/DPD model liquid pairs under several different nonequilibrium conditions, including transient and steady-state simple shear and planar elongational flows. Comparison of the MD simulation results with those of the scaled DPD simulations revealed that the optimized DPD model, expressed in terms of the proposed scaling method, successfully reproduced the computationally expensive MD results using relatively cheaper DPD simulations.

The American Orthopaedic Association's Own the Bone® database: a national quality improvement project for the treatment of bone health in fragility fracture patients.

The American Orthopaedic Association initiated the Own the Bone (OTB) quality improvement program in 2009. Herein we show that the data collected through this program is similar to that collected in other large studies. Thus, the OTB registry functions as an externally valid cohort for studying fragility fracture patients. INTRODUCTION: The American Orthopedic Association initiated the Own the Bone (OTB) quality improvement program in 2009 to improve secondary prevention of fragility fractures. In this study, we present a summary of the data collected by the OTB program and compare it to data from other large fragility fracture registries with an aim to externally validate the OTB registry. METHODS: The OTB registry contained 35,038 unique cases of fragility fracture as of September, 2016. We report the demographics, presenting fracture characteristics, past fracture history, and bone mineral density (BMD) data and compare these to data from large fragility fracture studies across the world. RESULTS: Seventy-three percent of the patients in the OTB registry were female, Caucasian, and post-menopausal. In 54.4% of cases, patients had a hip fracture; spine fractures were the second most common fracture type occurring in 11.1% of patients. Thirty-four percent of the patients had a past history of fragility fracture, and the most common sites were the spine and hip. The average femoral neck T-score was - 2.06. When compared to other studies, the OTB database showed similar findings with regard to patient age, gender, race, BMI, BMD profile, prior fracture history, and family history of fragility fractures. CONCLUSION: OTB is the first and largest multi-center voluntary fragility fracture registry in the USA. The data collected through the OTB program is comparable to that collected in international studies. Thus, the OTB registry functions as an externally valid cohort for further studies assessing the clinical characteristics, interventions, and outcomes achieved in patients who present with a fragility fracture in the USA.

Elevated incidence of fractures in women with invasive breast cancer.

UNLABELLED: This study evaluates the incidence of bone fractures in women with BC.We found that women with invasive breast cancer are at an increased risk for bone fractures, with fractures most commonly occurring at lower extremity and vertebral sites. The risk is further increased in women undergoing cancer therapy. INTRODUCTION: Bone loss and fractures in breast cancer have generally been attributed to aromatase inhibitor use. This study assessed the incidence of fractures after invasive breast cancer diagnosis and evaluated bone density and FRAX risk calculation at time of fracture occurrence. METHODS: Retrospective cohort study of women with invasive breast cancer [June 2003-December 2011] who participated in an academic hospital based genetic biobank. Demographic and clinical characteristics were abstracted from the electronic medical record (EMR). RESULTS: A total of 422 women with invasive breast cancer were assessed; 79 (28 %) sustained fractures during the observation period; fractures occurred at multiple skeletal sites in 27 cases (116 fractures). The incidence of fractures was 40 per 1000 person-years. Women who sustained fractures were mostly white and had a family history of osteoporosis (36.9 %, p = 0.03) or history of a prior fracture (6/79, p = 0.004). Fractures occurred 4.0 years (range 0-12 years) after cancer diagnosis. Fracture cases had femoral neck bone mineral density (BMD) of 0.72 + 0.12 g/cm(2), T-score of -1.2, that is, within the low bone mass range. Fractures most commonly occurred in lower extremities, vertebral, and wrist sites. Hip fractures accounted for 11 % of fractures, occurring at a median age of 61 years. CONCLUSIONS: Fractures occur shortly after commencing cancer therapy. Rapid bone loss associated with cancer therapy may precipitate fractures. Fractures occur at relatively higher BMD in BC. Occurrence of fractures in invasive breast cancer raises the possibility of cancer-induced impairment in bone quality.

Advancing pharmacovigilance through academic-legal collaboration: the case of gadolinium-based contrast agents and nephrogenic systemic fibrosis-a Research on Adverse Drug Events and Reports (RADAR) report.

OBJECTIVE: To compare and contrast three databases, that is, The International Centre for Nephrogenic Systemic Fibrosis Registry (ICNSFR), the Food and Drug Administration Adverse Event Reporting System (FAERS) and a legal data set, through pharmacovigilance and to evaluate international nephrogenic systemic fibrosis (NSF) safety efforts. METHODS: The Research on Adverse Drug events And Reports methodology was used for assessment-the FAERS (through June 2009), ICNSFR and the legal data set (January 2002 to December 2010). Safety information was obtained from the European Medicines Agency, the Danish Medicine Agency and the Food and Drug Administration. RESULTS: The FAERS encompassed the largest number (n = 1395) of NSF reports. The ICNSFR contained the most complete (n = 335, 100%) histopathological data. A total of 382 individual biopsy-proven, product-specific NSF cases were analysed from the legal data set. 76.2% (291/382) identified exposure to gadodiamide, of which 67.7% (197/291) were unconfounded. Additionally, 40.1% (153/382) of cases involved gadopentetate dimeglumine, of which 48.4% (74/153) were unconfounded, while gadoversetamide was identified in 7.3% (28/382) of which 28.6% (8/28) were unconfounded. Some cases involved gadobenate dimeglumine or gadoteridol, 5.8% (22/382), all of which were confounded. The mean number of exposures to gadolinium-based contrast agents (GBCAs) was gadodiamide (3), gadopentetate dimeglumine (5) and gadoversetamide (2). Of the 279 unconfounded cases, all involved a linear-structured GBCA. 205 (73.5%) were a non-ionic GBCA while 74 (26.5%) were an ionic GBCA. CONCLUSION: Clinical and legal databases exhibit unique characteristics that prove complementary in safety evaluations. Use of the legal data set allowed the identification of the most commonly implicated GBCA. ADVANCES IN KNOWLEDGE: This article is the first to demonstrate explicitly the utility of a legal data set to pharmacovigilance research.

Reporting of serious adverse events during cancer clinical trials to the institutional review board: an evaluation by the research on adverse drug events and reports (RADAR) project.

Global introspection is considered an unreliable method for attribution of causality of serious adverse events (SAEs), yet remains widely used for cancer drug clinical trials. Here, we compare structured case abstraction (SCA) to the routine method for detecting, evaluating, and reporting ADEs during cancer drug clinical trials to an Institutional Review Board (IRB). We obtained all SAE reports (2001-2008) received by one IRB for six clinical trials involving bevacizumab or oxaliplatin for treatment of gastrointestinal cancers. We compared the routine IRB SAE method to SCA for adverse event detection and causality attribution. Of 205 adverse events, 182 events (75%) were not reported; of these, 6 (20%) of 30 SAEs requiring an IRB report were unreported. For the 10 item Naranjo score, the amount of information useful for causality attribution was higher with SCA than the routine method (6.0 vs. 2.4 items, P < .0001). One-fifth of SAEs requiring an IRB report were unreported to the IRB via the routine method. SCA provided more useful information as to whether an SAE was caused by a cancer drug exposure. Our results suggest that SCA may improve SAE detection and the accuracy of attribution of causality during cancer drug clinical trials.

Development of an electronic medical record based intervention to improve medical care of osteoporosis.

UNLABELLED: Osteoporosis is infrequently addressed during hospitalization for osteoporotic fractures. An EMR-based intervention (osteoporosis order set) was developed with physician and patient input. There was a trend toward greater calcium supplementation from July 2008 to April 2009 (s = 0.058); however, use of antiresorptives (13%) or discharge instructions for BMD testing and osteoporosis treatment (10%) remained low. INTRODUCTION: Osteoporosis is infrequently addressed during hospitalization for osteoporotic fractures. The study population consisted of patients over 50 years of age. METHODS: Northwestern Memorial Hospital is a tertiary care academic hospital in Chicago. This study was conducted from September 1, 2007 through June 30, 2009. RESULTS: Physicians reported that barriers to care comprised nonacute nature of osteoporosis, belief that osteoporosis should be addressed by the PCP, low awareness of recurrent fractures, and radiographs with terms such as "compression deformity", "wedge deformity", or "vertebral height loss" which in their opinion were not clearly indicative of vertebral fractures. An EMR-based intervention was developed with physician and patient input. Over the evaluation period, 295 fracture cases in individuals over the age of 50 years in the medicine floors were analyzed. Mean age was 72 ± 11 years; 74% were female. Sites of fracture included hip n = 78 (27%), vertebral n = 87 (30%), lower extremity n = 61 (21%), upper extremity n = 43 (15%) and pelvis n = 26 (9%). There was no increase in documentation of osteoporosis in the medical record from pre- to post-EMR implementation (p = 0.89). There was a trend toward greater calcium supplementation from July 2008 to April 2009 (p = 0.058); however, use of antiresorptives (13%) or discharge instructions for BMD testing and osteoporosis treatment (10%) remained low. CONCLUSION: An electronic medical record intervention without electronic reminders created with physician input achieves an increase in calcium supplementation but fails to increase diagnosis or treatment for osteoporosis at the time of hospitalization for a fragility fracture.

Elevated incidence of fractures in solid-organ transplant recipients on glucocorticoid-sparing immunosuppressive regimens.

This study was conducted to assess the occurrence of fractures in solid-organ transplant recipients. Methods. Medical record review and surveys were performed. Patients received less than 6 months of glucocorticoids. Results. Of 351 transplant patients, 175 patients provided fracture information, with 48 (27.4%) having fractured since transplant (2-6 years). Transplants included 19 kidney/liver (50% male), 47 kidney/pancreas (53% male), 92 liver (65% male), and 17 pancreas transplants (41% male). Age at transplant was 50.8 ± 10.3 years. Fractures were equally seen across both genders and transplant types. Calcium supplementation (n = 94) and bisphosphonate therapy (n = 52) were observed, and an association with a lower risk of fractures was noted for bisphosphonate users (OR = 0.45 95% C.I. 0.24, 0.85). Fracture location included 8 (16.7%) foot, 12 (25.0%) vertebral, 3 (6.3%) hand, 2 (4.2%) humerus, 5 (10.4%) wrist, 10 (20.8%) fractures at other sites, and 7 (14.6%) multiple fractures. The estimated relative risk of fracture was nearly seventeen-times higher in male liver transplant recipients ages 45-64 years compared with the general male population, and comparable to fracture rates on conventional immunosuppressant regimens. Conclusion. We identify a high frequency of fractures in transplant recipients despite limited glucocorticoid use.

Greater osteoporosis educational outreach is desirable among Chinese immigrants in Chinatown, Chicago.

UNLABELLED: Osteoporosis beliefs were assessed in immigrant Chinese women in Chinatown, Chicago. Results from a survey utilizing the Osteoporosis Health Belief Scale showed that women expressed concern about osteoporosis but lacked both knowledge of preventive care and health motivation. INTRODUCTION: The objective of this study was to assess osteoporosis beliefs in immigrant Chinese women in Chinatown, Chicago. METHODS: In a community-based health fair, osteoporosis knowledge and self-efficacy among postmenopausal Chinese immigrants were assessed using the translated Osteoporosis Health Belief Scale. Bone mineral density (BMD) was assessed with calcaneal ultrasound. RESULTS: The study population included 94 women with mean age of 51 +/- 9 years, mean length of residence in the United States of 9 +/- 7 years, and 73% (n = 76) of whom were recent immigrants. Women expressed concern about the seriousness of osteoporosis and their relative susceptibility to osteoporosis. In particular, women with a prior fracture reported higher seriousness to osteoporosis. Nonetheless, women exhibited low health motivation and low awareness of the benefits of calcium and exercise. Bone densitometry results corresponded to a T score of -1.2 +/- 1.5. Multiple regression analysis revealed that a younger age and longer length of residence in the USA were associated with higher BMD. CONCLUSION: Chinese immigrant women in Chicago exhibit concern regarding osteoporosis, but are unaware of the benefits of calcium and exercise, and exhibit low health motivation. Chinese women in Chinatown lack necessary knowledge about osteoporosis to develop adequate self-efficacy. Public health initiatives should be undertaken among recent immigrant Chinese women.

Secondary contributors to bone loss in osteoporosis related hip fractures.

UNLABELLED: Osteoporosis treatment of patients with hip fractures is necessary to prevent subsequent fractures. Secondary causes for bone loss are present in more than 80% of patients with hip fractures, and therefore, assessment of Vitamin D status, disorders in calcium absorption and excretion, monoclonal gammopathies, and renal function should be performed. Identifying and managing these disorders will improve detection and enhance treatment aimed at reducing the risk of recurrent fractures in older adults. INTRODUCTION: The purpose of this study was to determine the prevalence of disorders affecting bone and mineral metabolism in individuals with osteoporotic hip fractures. METHODS: Community dwelling individuals with hip fractures (HFx) 50 years of age and older. Assessment for vitamin D, renal and parathyroid status, calcium absorption, and plasma cell disorders. RESULTS: Of 157 HFx, mean age 70 +/- 10 years, HFx had higher creatinine (p = 0.002, 95% C.I. -0.09, 0.05); lower 25 OH vitamin D (p = 0.019, 95% C.I. 6.5, 2.7), albumin (p = 0.007, 95% C.I. 0.36, 0.009), and 24-h urine calcium (p = 0.024, 95% CI 51, 21) as compared to controls. More than 80% of HFx had at least one previously undiagnosed condition, with vitamin D insufficiency (61%), chronic kidney disease (16%) (CKD), monoclonal gammopathy (6%), and low calcium absorption (5%) being the most common. One case each of multiple myeloma and solitary plasmocytoma were identified. CONCLUSIONS: Osteoporosis treatment of HFx is necessary to prevent subsequent fractures. Secondary causes for bone loss are remarkably common in HFx; therefore, assessment of vitamin D status, disorders in calcium absorption and excretion, protein electrophoresis, and renal function should be performed. Identifying and correcting these disorders will improve detection and enhance treatment aimed at reducing the risk of recurrent fractures in older adults.

Visualization of conformational changes of linear short-chain polyethylenes under shear and elongational flows.

We have performed nonequilibrium molecular dynamic simulations of the linear short-chain polyethylene liquids C(24)H(50), C(50)H(102), C(78)H(158), and C(128)H(258) under homogenous shear and elongational flows. We present visualizations of the molecular structure of each of the four liquids under shear and elongation, and compare them with their equilibrium static structures. These graphics provide a structural understanding of the various statistical measures that have been used in the literature to characterize the change in chain conformation as a function of strain rate and chain length. Moreover, these graphics allow a visualization of the inherent chain dynamics and orientation induced by shear and elongational flows. We discuss the molecular-level mechanisms apparent in the graphics.

A validation of the p-SLLOD equations of motion for homogeneous steady-state flows.

A validation of the p-SLLOD equations of motion for nonequilibrium molecular dynamics simulation under homogeneous steady-state flow is presented. We demonstrate that these equations generate the correct center-of-mass trajectory of the system, are completely compatible with (and derivable from) Hamiltonian dynamics, satisfy an appropriate energy balance, and require no fictitious external force to generate the required homogeneous flow. It is also shown that no rigorous derivation of the SLLOD equations exists to date.

Rheological and structural studies of linear polyethylene melts under planar elongational flow using nonequilibrium molecular dynamics simulations.

We present various rheological and structural properties of three polyethylene liquids, C50H102, C78H158, and C128H258, using nonequilibrium molecular dynamics simulations of planar elongational flow. All three melts display tension-thinning behavior of both elongational viscosities, eta1 and eta2. This tension thinning appears to follow the power law with respect to the elongation rate, i.e., eta approximately epsilon(b), where the exponent b is shown to be approximately -0.4 for eta1 and eta2. More specifically, b of eta1 is shown to be slightly larger than that of eta2 and to increase in magnitude with the chain length, while b of eta2 appeared to be independent of the chain length. We also investigated separately the contribution of each mode to the two elongational viscosities. For all three liquids, the intermolecular Lennard-Jones (LJ), intramolecular LJ, and bond-stretching modes make positive contributions to both eta1 and eta2, while the bond-torsional and bond-bending modes make negative contributions to both eta1 and eta2. The contribution of each of the five modes decreases in magnitude with increasing elongation rate. The hydrostatic pressure shows a clear minimum at a certain elongation rate for each liquid, and the elongation rate at which the minimum occurs appears to increase with the chain length. The behavior of the hydrostatic pressure with respect to the elongation rate is shown to correlate with the intermolecular LJ energy from a microscopic viewpoint. On the other hand, R(ete)2 and R(g)2 appear to be correlated with the intramolecular LJ energy. The study of the effect of the elongational field on the conformation tensor c shows that the degree of increase of tr(c)-3 with the elongation rate becomes stronger as the chain length increases. Also, the well-known linear reaction between sigma and c does not seem to be satisfactory. It seems that a simple relation between sigma and c would not be valid, in general, for arbitrary flows.

Structure formation under steady-state isothermal planar elongational flow of n-eicosane: a comparison between simulation and experiment.

We use nonequilibrium molecular dynamics simulations to investigate the structural properties of an oriented melt of n-eicosane under steady-state planar elongational flow. The flow-induced structure was evaluated using the structure factor s(k) taken as the Fourier transform of the total pair correlation function g(r). We found that the equilibrium liquid structure factor is in excellent agreement with the one determined via x-ray diffraction. Moreover, a new x-ray diffraction experiment has been performed on a crystalline n-eicosane sample. The resulting intramolecular contribution to the structure factor was found to be in very good agreement with the simulated one at a high elongation rate, indicating the existence of a possible crystalline precursor structure.

Effects of daytime ingestion of melatonin on short-term athletic performance.

The immediate effects of ingesting melatonin in the daytime include decreased alertness and body temperature. To date, no researcher has examined whether daytime ingestion of melatonin leads to impairments in variables relevant to short-term (<10 min) athletic performance. Twelve physically active participants (mean +/- s age = 25.2 +/- 5.0 years, body mass = 81.4 +/- 12.1 kg and chronotype = 33.8 +/- 6.3 units) ingested 5 mg of melatonin or placebo at 11:45 hours in a double-blind experiment. At 13:00 and 17:00 hours, subjective alertness was measured, together with intra-aural temperature, reaction time (two-, four- and eight-choice), short-term memory recall and grip strength. Performance, ratings of perceived exertion (RPE) and heart rate were also recorded during a 4-km cycling time trial. At 13:00 hours, the mean +/- s intra-aural temperature was 0.49 +/- 0.79 degrees C lower after ingestion of melatonin than after placebo (p = 0.015), but this difference was not apparent at 17:00 hours. At both 13:00 and 17:00 hours, melatonin reduced (p < 0.05) alertness, short-term memory and exercise heart rate by 1.5 +/- 1.8 units, 1 +/- 1 digits and 6 +/- 9 beats.min(-1), respectively (mean +/- s). Eight-choice reaction time was also slower at both times of day after ingesting melatonin. Melatonin did not influence time trial performance or RPE (p > 0.05). The effects of 5 mg of melatonin seem more pronounced for mental rather than physical components of short-term athletic performance, although the cardiovascular responses to exercise are affected. Some effects of melatonin were apparent 5 h after ingestion when the hypothermic effects of melatonin had dissipated.

Can cycling performance in an early morning, laboratory-based cycle time-trial be improved by morning exercise the day before?

The normal circadian rhythm in exercise performance may be altered by the habitual timing of training. We have investigated if morning time trial performance is affected by the time at which moderate exercise is performed on the previous day. Eight male cyclists undertook two separate exercise sessions of sub-maximal cycle ergometry (60% V.O2peak for 30 min) at 07:00 h and 12:00 h the day before a 16.1-km time trial at 07:00 h. Heart rate, power output, ratings of perceived exertion, and rectal temperature were measured at rest and every 5 min in the pre-time trial exercises, and every 1.61 km during the time trial. Blood samples were taken at rest and immediately after the time trial for the measurement of lactate concentration. The time trial performed the day after the 07:00 h sub-maximal exercise was completed in 1672+/-135 s, compared to 1706+/-159 s for the time trial performed the day after the noon pre-time trial exercise (p=0.027). The time trial after exercise the previous morning was associated with higher work-rates (p=0.031), a higher net lactate accumulation after the time trial (p=0.018), and a trend for higher heart rates (p=0.093) compared to the time trial after exercise the previous noon. These findings suggest that cycling performance in an early morning time trial is improved if an athlete participates in early-morning rather than noontime moderate exercise the day before. This finding cannot be attributed to the physiological responses to the exercise on the pre-time trial day or to environmental factors. It is suggested that it might partly reflect an advantage gained by performing exercise in the day(s) immediately beforehand at the same time as the competition.

Rheological and structural studies of liquid decane, hexadecane, and tetracosane under planar elongational flow using nonequilibrium molecular-dynamics simulations.

We report for the first time rheological and structural properties of liquid decane, hexadecane, and tetracosane using nonequilibrium molecular-dynamics (NEMD) simulations under planar elongational flow (PEF). The underlying NEMD algorithm employed is the so-called p-SLLOD algorithm [C. Baig, B. J. Edwards, D. J. Keffer, and H. D. Cochran, J. Chem. Phys. 122, 114103 (2005)]. Two elongational viscosities are measured, and they are shown not to be equal to each other, indicating two independent viscometric functions in PEF. With an appropriate definition, it is observed that the two elongational viscosities converge to each other at very low elongation rates, i.e., in the Newtonian regime. For all three alkanes, tension-thinning behavior is observed. At high elongation rates, chains appear to be fully stretched. This is supported by the result of the mean-square end-to-end distance of chains (R(ete2)) and the mean-square radius of gyration of chains (R(g2)), and further supported by the result of the intramolecular Lennard-Jones (LJ) potential energy. It is also observed that (R(ete2)) and (R(g2)) show a different trend as a function of strain rate from those in shear flow: after reaching a plateau value, (R(ete2)) and (R(g2)) are found to increase further as elongation rate increases. A minimum in the hydrostatic pressure is observed for hexadecane and tetracosane at about epsilon(msigma2/epsilon)1/2=0.02. This phenomenon is shown to be associated with the intermolecular LJ potential energy. The bond-bending and torsional energies display similar trends, but a different behavior is observed for the bond-stretching energy. An important observation common in these three bonded-intramolecular interactions is that all three modes are suppressed to a small value at high elongation rates. We conjecture that a liquid-crystal-like, nematic structure is present in these systems at high elongation rates, which is characterized by a strong chain alignment with a fully stretched conformation.

A proper approach for nonequilibrium molecular dynamics simulations of planar elongational flow.

We present nonequilibrium molecular dynamics simulations of planar elongational flow (PEF) by an algorithm proposed by Tuckerman et al. [J. Chem. Phys. 106, 5615 (1997)] and theoretically elaborated by Edwards and Dressler [J. Non-Newtonian, Fluid Mech. 96, 163 (2001)], which we shall call the proper-SLLOD algorithm, or p-SLLOD for short. [For background on names of algorithms see W. G. Hoover, D. J. Evans, R. B. Hickman, A. J. C. Ladd, W. T. Ashurst, and B. Moran, Phys. Rev. A 22, 1690 (1980) and D. J. Evans and G. P. Morriss, Phys. Rev. A 30, 1528 (1984).] We show that there are two sources for the exponential growth in PEF of the total linear momentum of the system in the contracting direction, which has been previously observed using the so-called SLLOD algorithm. The first comes from the SLLOD algorithm itself, and the second from the implementation of the Kraynik and Reinelt [Int. J. Multiphase Flow 18, 1045 (1992)] boundary conditions. Using the p-SLLOD algorithm (to eliminate the first source) implemented with our simulation strategy (to eliminate the second) in PEF simulations, we no longer observe the exponential growth. By analyzing the equations of motion, we also demonstrate that both the SLLOD and the DOLLS algorithms are intrinsically unsuitable for representing a nonequilibrium system with elongational flow. However, the p-SLLOD algorithm has a rigorously canonical structure in laboratory phase space, and thus can represent a nonequilibrium system not only for elongational flow but also for a general flow.

Frequency of low bone mass in elderly males attending an academic geriatric clinic: a pilot study.

The objective of this prospective study was to evaluate the frequency of low bone density in elderly males seen in an academic geriatric practice and to evaluate physician awareness of male osteoporosis among academic geriatricians. The participants were elderly community-dwelling ambulatory males aged 65 years and older (n = 35). The mean age was 80.7 +/- 8.2 years, with eight subjects in the 65-74 years range, 16 in the 75-84 years range and 11 over 85 years. Only 5/35 utilized an assistive device for ambulation. Bone mineral density (BMD) was measured using a heel ultrasound (QUS-2 calcaneal ultrasonometer). Clinical risk factors, gait and balance were evaluated (Tinetti scale). Results of BMD were communicated to the attending geriatrician. In all 7/35 participants had a calcaneal T-score of < or = -2.5 indicating osteoporosis, of these 50% were > 85 years; 7/35 had t score of -1 to -2.5 indicating osteopenia, of these 50% were 75-84 years; and 21/35 had a T-score > -1 indicating normal BMD). Overall, 14 of the 35 subjects studied had low bone density. Gait disorders were seen in 18/35 subjects (p < 0.05), more commonly in the oldest subjects. Risk factors for osteoporosis-related fractures included smoking (n = 22, 63%, p = 0.57), gait abnormalities (n = 18, 51%, p < 0.05) and alcohol use (n = 13, 37%, p = 0.39). Low bone mass (osteopenia or osteoporosis) was not addressed (by record notations, request for DEXA, laboratory testing or medical treatment) within 6 months by the majority of geriatricians (3/5). This pilot study shows a high frequency of low bone density in elderly males seen in an academic geriatric practice. This frail population presents with significant balance and gait disorders, and the coexistence of these two risk factors predisposes them to the development of hip fracture. This study also underscores the importance of increasing awareness of osteoporosis in males among geriatricians. Limitations to this study are that bone density was measured with the QUS-2 calcaneal ultrasonometer, and that female reference values were utilized. These limitations potentially under-estimate the prevalence of bone loss in males.

Use of melatonin in recovery from jet-lag following an eastward flight across 10 time-zones.

Subjective, physiological and physical performance variables are affected following travel across multiple time-zones (jet-lag). The objective of the study was to examine the effects of oral melatonin in alleviating jet-lag by investigating its effects on subjects who had flown from London to Eastern Australia, 10 time-zones to the east. Melatonin (5 mg day(-1)) or placebo capsules were administered to 14 experimental (13 males and 1 female) and 17 control subjects (15 males and 2 females), respectively, in a double-blind study; the time of administration was in accord with the current consensus for maximizing its hypnotic effect. Grip strength and intra-aural temperature were measured on alternate days after arrival at the destination, at four different times of day (between the times 07:00 - 08:00 h, 12:00 - 13:00 h, 16:00 - 17:00 h and 19:00 - 20:00 h local time). In addition, for the first 6 - 7 days after arrival in Australia, subjective ratings of jet-lag on a 0 - 10 visual analogue scale and responses to a Jet-lag Questionnaire (incorporating items for tiredness. sleep, meal satisfaction and ability to concentrate) were recorded at the above times and also on retiring (at about midnight). Subjects continued normally with their work schedules between the data collection times. Subjects with complete data (13 melatonin and 13 placebo subjects), in comparison with published data, showed partial adjustment of the diurnal rhythm in intra-aural temperature after 6 days. A time-of-day effect was evident in both right and left grip strength during adjustment to Australian time; there was no difference between the group taking melatonin and that using the placebo. Right and left grip strength profiles on day 6 were adjusted either by advancing or delaying the profiles, independent of whether subjects were taking melatonin or placebo tablets. Subjects reported disturbances with most measures in the Jet-lag Questionnaire but, whereas poorer concentration and some negative effects upon sleep had disappeared after 3 - 5 days, ratings of jet-lag and tiredness had not returned to 'zero' (or normal values), respectively, by the sixth day of the study. Subjects taking melatonin showed no significant differences from the placebo group in perceived irritability, concentration, meal satisfaction, ease in getting to sleep and staying asleep, frequency of bowel motion and consistency of the faeces. These results suggest that, in subjects who, after arrival, followed a busy schedule which resulted in frequent and erratic exposure to daylight, melatonin had no benefit in alleviating jet-lag or the components of jet-lag, and it did not influence the process of phase adjustment.

Assistive technology for postsecondary students with learning disabilities.

An increasing number of students with learning disabilities are attending postsecondary institutions. To meet the educational demands of these students, support service providers will likely rely on assistive technology. This article lists types of assistive technology appropriate for use with persons with learning disabilities at the postsecondary level and discusses ways in which assistive technology enhances learning. Additionally, an overview of legislation that has had an impact on assistive technology at the postsecondary level is presented. Issues involving assistive technology programs at the postsecondary level are discussed. Postsecondary assistive technology program components, device selection, and training guidelines also are outlined.