Elastic and vibrational properties of group IV semiconductors in empirical potential modelling

We have developed an interatomic potential that with a single set of parameters is able to accurately describe at the same time the elastic, vibrational and thermodynamics properties of semiconductors. The simultaneous inclusion of radial and angular forces of the interacting atom pairs (short range) together with the influence of the broken crystal symmetry when the atomic arrangement is out of equilibrium (long range) results in correct predictions of all of the phonon dispersion spectrum and mode-Grüneisen parameters of silicon and germanium. The long range interactions are taken into account up to the second nearest neighbours, to correctly influence the elastic and vibrational properties, and therefore represent only a marginal computational cost compared to the full treatment of other proposed potentials.Results of molecular dynamics simulations are compared with those of ab initio calculations, showing that when our proposed potential is used to perform the initial stages of the structural relaxation, a significant reduction of the computational time needed during the geometry optimization of density functional theory simulations is observed.

Incidence of serious side effects with intravenous bisphosphonate: a clinical audit

BACKGROUND

Bisphosphonates (BP) have been associated with osteonecrosis of the jaw (ONJ) and atypical femoral fractures (AFF). The prevalence of these side effects in intravenous (IV) BP-treated subjects is not well understood.

AIM

This audit aimed to delineate the prevalence of ONJ, thigh pain and AFF in patients having regular IV BP and its effect on bone mineral density (BMD). Design and

METHODS

Patients attending for IV BP over a 3-month period completed a questionnaire about thigh pain and dental health. Data concerning BMD, treatment indication and treatment history were obtained from medical records.

RESULTS

There were 201 patients between 28 and 94 years (74.1% female) mostly on zoledronate (ZOL) (102) or pamidronate (PAM) (97). Osteoporosis (75.6%) and Paget's disease (16.5%) were the main indications for treatment; median length of IV BP was 4 years (range 0.25-25). One patient had ONJ (0.5%) while oral pain was reported by 6.5% and 12.7% noted tooth loosening. Twenty-seven subjects (13.4%) complained of current thigh pain. AFF occurred in four patients (2%), none of whom had idiopathic osteoporosis. At time of AFF, only one patient had a femoral neck T-score less than -2.5. All four had received pamidronate treatment; median 12.5 years (range 7-22). IV BP treatment significantly increased lumbar spine BMD but not femoral neck BMD.

CONCLUSION

Classical ONJ was rare (0.5%), although tooth loss was more frequent. Thigh pain was frequent while AFF occurred in 2.0% of subjects and was associated with long treatment periods and non-osteoporotic bone.

Observation of public health risk behaviours, risk communication and hand hygiene at Kansas and Missouri petting zoos--2010-2011

Outbreaks of human illness have been linked to visiting settings with animal contact throughout developed countries. This study details an observational study of hand hygiene tool availability and recommendations; frequency of risky behaviour; and handwashing attempts by visitors in Kansas (9) and Missouri (4), USA, petting zoos. Handwashing signs and hand hygiene stations were available at the exit of animal-contact areas in 10/13 and 8/13 petting zoos, respectively. Risky behaviours were observed being performed at all petting zoos by at least one visitor. Frequently observed behaviours were as follows: children (10/13 petting zoos) and adults (9/13 petting zoos) touching hands to face within animal-contact areas; animals licking children's and adults' hands (7/13 and 4/13 petting zoos, respectively); and children and adults drinking within animal-contact areas (5/13 petting zoos each). Of 574 visitors observed for hand hygiene when exiting animal-contact areas, 37% (n = 214) of individuals attempted some type of hand hygiene, with male adults, female adults and children attempting at similar rates (32%, 40% and 37%, respectively). Visitors were 4.8× more likely to wash their hands when a staff member was present within or at the exit to the animal-contact area (136/231, 59%) than when no staff member was present (78/343, 23%; P < 0.001, OR = 4.863, 95% CI = 3.380-6.998). Visitors at zoos with a fence as a partial barrier to human-animal contact were 2.3× more likely to wash their hands (188/460, 40.9%) than visitors allowed to enter the animals' yard for contact (26/114, 22.8%; P < 0.001, OR = 2.339, 95% CI = 1.454-3.763). Inconsistencies existed in tool availability, signage and supervision of animal contact. Risk communication was poor, with few petting zoos outlining risks associated with animal contact, or providing recommendations for precautions to be taken to reduce these risks.

A critical role of dendritic cells in CD8 T cell IL-10 expression during inflammatory response triggered by CD40-activated B cells (159.16)

CD40LBTg mice, expressing a CD40 ligand (CD40L) transgene on B cells, represent a model for human diseases where B cells aberrantly express CD40L or receive excess CD40/CD40L signaling under inflammatory conditions. Here, we show that B cells expressing transgenic CD40L are capable of priming CD8 T cells and generate strong antigen-specific cytotoxicity. Adoptively transferred SIINFEKL peptide-loaded B cells from CD40LBTg but not wild type mice were able to activate self-reactive OT-I CD8 T cells upon immunization with OVA plus alum and trigger diabetes in RIP-OVA mice by enhancing the help of endogenous self-reactive CD4 T cells. CD40L expressing B cells also trigger spontaneous activation of splenic CD8 T cells, which rapidly up-regulate PD-1, Blimp-1 and LAG-3 and lose cytotoxicity along with IL-10 expression via interaction with PDL-1hi CD11c+ dendritic cells in T cell zones. Thus, CD11c+ dendritic cells from CD40LBTg mice exhibit regulatory phenotype, which block granzyme B expression and preferentially induce IL-10 expression in activated CD8 T cells. These results demonstrate that constitutive CD40 signaling on B cells under inflammation increases the risk of breaking peripheral CD8 T cell tolerance. However, the presence of CD40-activated B cells results in PDL-1hi CD11c+ dendritic cells, which exhibit a regulatory role to dampen harmful self-reactive cytotoxicity by promoting IL-10 expression in CD8 T cells.

The Task-Dependent Efficacy of Shared-Control Haptic Guidance Paradigms

Shared-control haptic guidance is a common form of robot-mediated training used to teach novice subjects to perform dynamic tasks. Shared-control guidance is distinct from more traditional guidance controllers, such as virtual fixtures, in that it provides novices with real-time visual and haptic feedback from a real or virtual expert. Previous studies have shown varying levels of training efficacy using shared-control guidance paradigms; it is hypothesized that these mixed results are due to interactions between specific guidance implementations ("paradigms") and tasks. This work proposes a novel guidance paradigm taxonomy intended to help classify and compare the multitude of implementations in the literature, as well as a revised proxy rendering model to allow for the implementation of more complex guidance paradigms. The efficacies of four common paradigms are compared in a controlled study with 50 healthy subjects and two dynamic tasks. The results show that guidance paradigms must be matched to a task's dynamic characteristics to elicit effective training and low workload. Based on these results, we provide suggestions for the future development of improved haptic guidance paradigms.

Parathyroid Hormone in Human Plasma: IMMUNOCHEMICAL CHARACTERIZATION AND BIOLOGICAL IMPLICATIONS

Antigenic recognition of four anti-bovine parathyroid hormone antisera was characterized by their reactivity with bovine hormonal fragments (1-34, 1-13, 14-34, 19-34, 53-84) and human hormone extracted from parathyroid adenomas. All antisera were found to have antibody populations which recognized more than one antigenic determinant and all antisera differed in their specificity and reactivity for the fragments of bovine hormone. By modification of two antisera, GP-1 and GP-133, by preincubation with excess concentrations of 1-34 or 53-84 fragments, antigenic recognition was restricted to defined regions of the hormonal sequence.When assays using these modified antisera were applied to the study of hormones extracted from glands, greater immunochemical similarities were seen between bovine and human parathyroid hormone using assays that were specific for the measurement of amino-terminal portions of the hormones than of the carboxy-terminal portions.When assays using these antisera were applied to the study of endogenous parathyroid hormone in human plasma, the immunoreactive hormone in the general circulation was shown to substantially lack an amino-terminal portion of the sequence of the intact hormone, including an antigenic determinant requiring all or some of the 14-19 region. This deletion accounts, at least in part, for the immunochemical heterogeneity of plasma parathyroid hormone in man. Radioimmunoassay of fractions of peripheral plasma subjected to gel filtration confirms that the dominant form of the immunoreactive hormone in the general circulation of man is a hormonal fragment that is totally devoid of amino-terminal reactivity. Because of this deletion, it can be concluded that most of the immunoreactive parathyroid hormone in the general circulation of man must be biologically inactive.

Reproductive performance measures among Thoroughbred mares in central Kentucky, during the 2004 mating season

REASON FOR PERFORMING STUDY

To improve efficiency at the farm level, a better understanding of how farm management factors impact reproductive performance is important.

OBJECTIVE

To assess reproductive efficiency and effectiveness among Thoroughbred mares in central Kentucky.

METHODS

A cohort of 1011 mares on 13 farms in central Kentucky was followed during the 2004 mating and 2005 foaling season. Information on farm level practices was collected via interviews with farm managers. Reproductive records were collected for each mare mated to obtain information on mare characteristics. The influence of mare age and status (maiden, foaling, barren) on Days 15 and 40 post mating pregnancy rates, foaling rates and total effective length of the mating season were assessed. The influence of stallion book size on reproductive performance measures was also examined.

RESULTS

Per season pregnancy rates on Days 15 and 40 post mating and live foal rate were 92.1, 89.3 and 783%, respectively. Per cycle rates for the same time periods were 64.0, 583 and 50.8%. There were no significant associations between stallion book size and reproductive performance outcomes. The mean +/- s.d. interval from the beginning of the mating season to the last mating of the mare was 36.5 +/- 26.1 days.

CONCLUSIONS

Mare age had a significant impact on efficiency of becoming pregnant, maintaining pregnancy and producing a live foal. Overall, fertility did not decrease among stallions with the largest book sizes. Total interval length of the mating season can be reduced if managers ensure maiden and barren mares are mated at the beginning of the season and foaling mares are mated at the earliest oestrus after acceptable uterine involution has been achieved.

POTENTIAL RELEVANCE

Measures identified in the study can be used by owners, farm managers and veterinarians to improve mare reproductive performance and identify parameters to assist with the implementation of effective culling practices.