Convergence of Time-Derivative Nonadiabatic Couplings in Plane-Wave DFT Calculations.

Accurate prediction of charge carrier relaxation rates is essential to design molecules and materials with the desired photochemical properties for applications like photocatalysis and solar energy conversion. Nonadiabatic molecular dynamics allows one to simulate the relaxation process of excited charge carriers. Plane-wave density functional theory (DFT) calculations make the time-derivative nonadiabatic couplings (TNACs) simple to compute because the basis is independent of the atomic positions. However, the effect of the kinetic energy cutoff for the plane-wave basis on the accuracy of the dynamics has not been studied. Here, we examine the effect of the kinetic energy cutoff on the TNACs and decay time scales for the prototypical model system of tetracene. These calculations show that the choice of kinetic energy cutoff can change the relaxation time by up to 30%. The relaxation times of states that have small TNACs to other states or are far from degenerate are more sensitive to the kinetic energy cutoff than those of states with large TNACs or near degeneracies. A kinetic energy cutoff of 60 Ry is sufficient for all states to reach semiquantitative agreement (absolute error <10%) with the decay times of our 110 Ry reference data, and a cutoff of 80 Ry is required for all states to reach quantitative agreement (absolute error <2%).

Evolution of plasmon-like excited states in silver nanowires and nanorods.

Silver nanowires and nanorods are useful prototypical systems to study the emergence of plasmons within a quantum mechanical context because their high aspect ratios enable plasmons to emerge in smaller systems than for roughly spherical nanoclusters. Here, we quantify the plasmon-like character of the excited states of silver nanorods and nanowires based on three nearly orthogonal criteria: (1) collectivity, (2) dipole additivity, and (3) superatomic character. Based on these three criteria, we classify the excited states as plasmon-like, collective, single-particle, interband, or as intermediate between these categories. We show that linear nanowires have a longitudinal absorption peak that has single-particle character and a transverse absorption peak that evolves from a single-particle to plasmon-like to a mix of plasmon-like and interband with increasing length. Increasing the width tends to increase the plasmon-like character of the longitudinal excited state. In contrast, increasing the nanorod width tends to decrease the length at which interband transitions start mixing significantly into the transverse plasmon-like excited states.

Cutaneous inoculation tuberculosis in a healthcare worker: Case report and literature review.

In all health care settings, particularly those in developing countries, healthcare workers have a high risk for exposure to tuberculosis. Tuberculosis can involve any organ, including the skin. Cutaneous tuberculosis is uncommon and may be secondary to an exogenous inoculation. We report the case of a surgical resident at a tertiary care hospital in Lima, Peru who developed cutaneous inoculation tuberculosis after sustaining a needlestick injury while performing a diagnostic cervical lymph node aspiration from a patient with HIV infection and tuberculous cervical lymphadenopathy.

The use of dual-energy X-ray absorptiometry to assess the impact of Eimeria infections in broiler chicks.

A number of parameters have been used to assess the impact ofcoccidiosis on chickens in clinical settings as well as in experimental studies. However, a rapid way to determine body composition would be useful to evaluate or compare responses to coccidia and could give further insight into the metabolic impact of infection. The current study evaluates the use of dual X-ray absorptiometry (DEXA) to determine the impact of coccidiosis on body composition in chicks receiving inoculations with single or mixed species of Eimeria. Chicks infected with Eimeria maxima, Eimeria acervulina, or Eimeria tenella had altered parameters of body composition as measured by DEXA at 6 days postinfection (PI). The greatest effects were noted in birds infected with E. acervulina or E. maxima, where lean mass and fat were reduced from control values about 75% and 85%, respectively. In chicks infected with E. tenella, tissue and fat were reduced about 10%. Bone mineral content (BMC) was about 75% of control values in birds infected with E. acervulina or E. maxima, but only E. acervulina altered bone mineral density (BMD). The decreases in BMC and BMD are likely due to malabsorption. In chicks receiving a mixed coccidian infection, all DEXA parameters were significantly decreased at 8 days PI compared with age-matched controls. As with single infections, BMD and BMC were significantly depressed (P < 0.05). Values of all DEXA parameters were near 92% of control values by day 16 PI. Analysis of all birds in the current study indicates DEXA tissue weight slightly underestimated the gravimetrically measured weight by about 3%. The current results demonstrate that DEXA is a potentially important tool for the rapid evaluation of the effect of coccidiosis on broiler chicks and suggest it can be useful for evaluation of vaccines and other disease controls.

Transgenic overexpression of bone morphogenetic protein 11 propeptide in skeleton enhances bone formation.

Bone morphogenetic protein 11 (BMP11) is a key regulatory protein in skeletal development. BMP11 propeptide has been shown to antagonize GDF11 activity in vitro. To explore the role of BMP11 propeptide in skeletal formation in vivo, we generated transgenic mice with skeleton-specific overexpression of BMP11 propeptide cDNA. The mice showed a transformation of the seventh cervical vertebra into a thoracic vertebra in our previous report. Presently, further characterizations of the transgenic mice indicated that ossification in calvatia was dramatically enhanced in transgenic fetuses at 16.5 dpc in comparison with their wild-type littermates. At 10 weeks of age, bone mineral content and bone mineral density were significantly (P<0.05) higher in transgenic mice than that in their wild-type littermates based on dual energy X-ray absorptiometry analysis. The relative trabecular bone volume measured by histological analysis was dramatically increased in transgenic mice compared with their wild-type littermates. The enhanced bone formations in the transgenic mice appear to result from increase osteoblast activities as the expressions of four osteoblast markers - α1 type 1 collagen, osteocalcin, alkaline phosphatase and phex were significantly higher in transgenic fetuses than that in their wild-type littermates. These results suggest that over-expression of BMP11 propeptide stimulates bone formation by increasing osteoblast cell functions.

Validation of quantitative magnetic resonance body composition analysis for infants using piglet model.

A study was conducted to validate the use of a quantitative magnetic resonance (QMR) device for measuring the body composition of infants and neonates weighing < 12 kg using the pig as a model. A total of 25 piglets weighing between 2 and 12 kg were studied. Body composition was assessed by QMR, dual-energy x-ray absorptiometry (DXA), and whole-body chemical analysis (CA) of carcass for lipid and water content. The precision, mean and SD of repeated measurements, of QMR to estimate fat mass (FM), lean mass (LM), and total body water (TBW) for five consecutive scans with reposition was 12.5, 32.0, and 36.0 g, respectively. QMR measures of FM, LM, and TBW were highly and significantly correlated with CA of carcass. In terms of accuracy, mean difference between QMR and CA (percent of mean value for CA), QMR overestimated FM by 40 g (4.7%), overestimated LM by 114.9 g (2.1%), and underestimated TBW by 134.6 g (3.1%). This study concludes that QMR provides precise and accurate measures of FM, LM, and TBW in piglet weighing up to 12 kg. These results suggest that QMR can provide valuable body composition data in longitudinal studies in infants.

Calibration and validation of EchoMRI™ whole body composition analysis based on chemical analysis of piglets, in comparison with the same for DXA.

A study was conducted to appraise a new EchoMRI™ device for body composition analysis (BCA) of infants and to compare it with dual energy X-ray absorptiometry (DXA), using chemical analysis as a reference method.The calibration part of the study included cross-validation comparisons between EchoMRI™ measurements of awake, anesthetized and dead piglets of the calibration set. It also included comparison of two different approaches to refining the calibration of EchoMRI™, by low- or by high-dimensional linear regressions. Only the low-dimensional approach was applied to DXA.The validation part yielded EchoMRI™ accuracy of 27 g and 70 g for fat and total water, respectively, on piglets scanned while anesthetized, as compared with 24 g and 57 g, respectively, for DXA.EchoMRI™ precision was found to be 4 g and 7 g for fat and total water, respectively, for anesthetized piglets, as compared to 16 g and 14 g, respectively, for DXA. The differences between fat measurements of awake, anesthetized and dead piglets can be statistically significant, but are comparable in magnitude to random errors.To summarize: Characterization of random errors by CV, especially that of fat, is not suitable for BCA, whereas absolute errors or errors relative to total body weight can be applicable. Low- and high-dimensional regressions offer nearly the same accuracy improvements. Improved DXA and EchoMRI™ offer nearly the same accuracy, within 1% of weight in fat, while EchoMRI™ has better precision, within 0.2 % of weight in fat for anesthetized and dead piglets as compared to DXA's 0.5-0.6%.

Evidence based medicine and effective interventions of pharmacological therapy for the prevention of osteoporotic fractures.

Osteoporosis and fractures associated with it constitute a real and serious socio-medical problem, which only recently has come to the forefront of social consciousness. The authors are carrying out a critical re-examination of the medical literature of osteoporosis pharmacological treatment. Particular attention has been paid to studies which show a clear reduction of the primary endpoint that, in the case of this pathology, consists of a reduction of the fracturing event. According to the examination of the clinical studies introduced, antiresorptive bone agents, such as alendronate and risenderonate, turn out to be molecules with higher levels of evidence implicated on the reduction of the main osteoporotic fractures, in particular the reduction of vertebral and femoral fractures. The 10 years long-term extension studies, in particular those that have seen the employment of alendronate, found a positive outcome regarding densitometry data and a favorable trend in antifracture effectiveness. Ibandronate is another amino-bisphosphonate which was recently validated as an effective drug for the treatment of osteoporosis with its documented ability to meaningfully reduce vertebral fractures. Also ranelate of strontium, a drug that seems to explain its own result in a different way from the other antiresorptive bone agents, constitutes another valid alternative in the treatment of this pathology. Both of these molecules however, need further studies in order to estimate their antifracture effectiveness in the long term, particularly those related to femoral fractures. Teriparatide and the entire molecule paratohormone are usually not prescribed for its high cost in treatment and because, typically, patients with high-risk level fractures that are already affected, produce more vertebral fractures from moderate to severe intensity.