Power-Law Scaling Relating the Average Charge State and Kinetic Energy in Expanding Laser-Driven Plasmas.

A universal power-law scaling z[over ¯]∝E^{0.4} in the correlation between the average ion charge state z[over ¯] and kinetic energy E in expanding laser-driven tin plasmas is identified. Universality here refers to an insensitivity to all experimental conditions: target geometry, expansion direction, laser wavelength, and power density. The power law is accurately captured in an analytical consideration of the dependence of the charge state on temperature and the subsequent transfer of internal to kinetic energy in the expansion. These analytical steps are individually, and collectively, validated by a two-dimensional radiation-hydrodynamic simulation of an expanding laser-driven plasma. This power-law behavior is expected to hold also for dense plasma containing heavier, complex ions such as those relevant to current and future laser-driven plasma light sources.

Increased gene expression of the cardiac endothelin system in obese mice.

Obesity is a well-known risk factor of atherosclerosis and heart failure. In the human heart, a local endothelin system containing prepro-endothelin-1, endothelin-converting enzyme-1, and endothelin receptors A and B has been described. The endothelin system is activated in heart failure; however, the impact of obesity on the cardiac endothelin system is unknown. In this study, 18-week-old male C57BL/6 mice fed either a control diet or a high-fat diet for 10 weeks were analyzed. High-fat diet significantly increased the body weight of the animals and augmented low-density lipoprotein, high-density lipoprotein, and cholesterol plasma levels, compared to control. The animal groups showed no significant differences in left ventricular size or function (heart rate, ejection fraction, fractional shortening, left ventricular posterior wall thickness, cardiac output) after control or high-fat diet. We did not observe signs of cardiac hypertrophy or changes in markers of cardiac fibrosis in these heart samples. The cardiac expression of prepro-endothelin-1 mRNA, endothelin-converting enzyme-1 mRNA, and protein and endothelin receptors A and B mRNA was increased in 18-week-old obese C57BL/6 mice compared to animals with normal weight (p<0.05 vs. control). Furthermore, endothelin-1 plasma levels showed an increasing trend. In conclusion, an increased expression of genes of the endothelin system was observed in the hearts of 18-week-old mice after high-fat diet, possibly contributing to later cardiovascular complications of obesity.

Semiconducting-to-metallic photoconductivity crossover and temperature-dependent Drude weight in graphene.

We investigate the transient photoconductivity of graphene at various gate-tuned carrier densities by optical-pump terahertz-probe spectroscopy. We demonstrate that graphene exhibits semiconducting positive photoconductivity near zero carrier density, which crosses over to metallic negative photoconductivity at high carrier density. These observations can be accounted for by the interplay between photoinduced changes of both the Drude weight and carrier scattering rate. Our findings provide a complete picture to explain the opposite photoconductivity behavior reported in (undoped) graphene grown epitaxially and (doped) graphene grown by chemical vapor deposition. Notably, we observe nonmonotonic fluence dependence of the photoconductivity at low carrier density. This behavior reveals the nonmonotonic temperature dependence of the Drude weight in graphene, a unique property of two-dimensional massless Dirac fermions.

Trion-induced negative photoconductivity in monolayer MoS2.

Optical excitation typically enhances electrical conduction and low-frequency radiation absorption in semiconductors. We, however, observe a pronounced transient decrease of conductivity in doped monolayer molybdenum disulfide (MoS(2)), a two-dimensional (2D) semiconductor, using ultrafast optical-pump terahertz-probe spectroscopy. In particular, the conductivity is reduced to only 30% of its equilibrium value at high pump fluence. This anomalous phenomenon arises from the strong many-body interactions in the 2D system, where photoexcited electron-hole pairs join the doping-induced charges to form trions, bound states of two electrons and one hole. The resultant increase of the carrier effective mass substantially diminishes the conductivity.

Spin-induced optical conductivity in the spin-liquid candidate herbertsmithite.

We report a direct measurement of the low-frequency optical conductivity of large-area single-crystal herbertsmithite, a promising spin-liquid candidate material, by means of terahertz time-domain spectroscopy. In the spectral range below 1.4 THz, we observe a contribution to the real part of the in-plane conductivity σ(ab)(ω) from the spin degree of freedom. This spin-induced conductivity exhibits a power-law dependence on frequency σ(ab)(ω) ~ ω(ß) with ß ≈ 1.4. Our observation is consistent with the theoretically predicted low-frequency conductivity arising from an emergent gauge field of a gapless U(1) Dirac spin liquid.

Effect of classroom air quality on students' concentration: results of a cluster-randomized cross-over experimental study.

UNLABELLED: To assess the effect of indoor air quality as indicated by the median carbon dioxide (CO2) level in the classroom on the concentration performance (CP) of students, a cross-over cluster-randomized experimental study was conducted in 20 classrooms with mechanical ventilation systems. Test conditions 'worse' (median CO2 level on average 2115 ppm) and 'better' (median CO2 level on average 1045 ppm) were established by the regulation of the mechanical ventilation system on two days in one week each in every classroom. Concentration performance was quantified in students of grade three and four by the use of the d2-test and its primary parameter 'CP' and secondary parameters 'total number of characters processed' (TN) and 'total number of errors' (TE). 2366 d2-tests from 417 students could be used in analysis. In hierarchical linear regression accounting for repeated measurements, no significant effect of the experimental condition on CP or TN could be observed. However, TE was increased significantly by 1.65 (95% confidence interval 0.42-2.87) in 'worse' compared to 'better' condition. Thus, low air quality in classrooms as indicated by increased CO2 levels does not reduce overall short-term CP in students, but appears to increase the error rate. PRACTICAL IMPLICATIONS: This study could not confirm that low air quality in classrooms as indicated by increased CO2 levels reduces short-term concentration performance (CP) in students; however, it appears to affect processing accuracy negatively. To ensure a high level of accuracy, good air quality characterized, for example, by low CO2 concentration should be maintained in classrooms.

Exploring ITM2A as a new potential target for brain delivery.

BACKGROUND: Integral membrane protein 2A (ITM2A) is a transmembrane protein expressed in a variety of tissues; little is known about its function, particularly in the brain. ITM2A was found to be highly enriched in human brain versus peripheral endothelial cells by transcriptomic and proteomic studies conducted within the European Collaboration on the Optimization of Macromolecular Pharmaceutical (COMPACT) Innovative Medicines Initiative (IMI) consortium. Here, we report the work that was undertaken to determine whether ITM2A could represent a potential target for delivering drugs to the brain. METHODS: A series of ITM2A constructs, cell lines and specific anti-human and mouse ITM2A antibodies were generated. Binding and internalization studies in Human Embryonic Kidney 293 (HEK293) cells overexpressing ITM2A and in brain microvascular endothelial cells from mouse and non-human primate (NHP) were performed with these tools. The best ITM2A antibody was evaluated in an in vitro human blood brain barrier (BBB) model and in an in vivo mouse pharmacokinetic study to investigate its ability to cross the BBB. RESULTS: Antibodies specifically recognizing extracellular parts of ITM2A or tags inserted in its extracellular domain showed selective binding and uptake in ITM2A-overexpressing cells. However, despite high RNA expression in mouse and human microvessels, the ITM2A protein was rapidly downregulated when endothelial cells were grown in culture, probably explaining why transcytosis could not be observed in vitro. An attempt to directly demonstrate in vivo transcytosis in mice was inconclusive, using either a cross-reactive anti-ITM2A antibody or in vivo phage panning of an anti-ITM2A phage library. CONCLUSIONS: The present work describes our efforts to explore the potential of ITM2A as a target mediating transcytosis through the BBB, and highlights the multiple challenges linked to the identification of new brain delivery targets. Our data provide evidence that antibodies against ITM2A are internalized in ITM2A-overexpressing HEK293 cells, and that ITM2A is expressed in brain microvessels, but further investigations will be needed to demonstrate that ITM2A is a potential target for brain delivery.

Soliton superlattices in twisted hexagonal boron nitride.

Properties of atomic van der Waals heterostructures are profoundly influenced by interlayer coupling, which critically depends on stacking of the proximal layers. Rotational misalignment or lattice mismatch of the layers gives rise to a periodic modulation of the stacking, the moiré superlattice. Provided the superlattice period extends over many unit cells, the coupled layers undergo lattice relaxation, leading to the concentration of strain at line defects - solitons - separating large area commensurate domains. We visualize such long-range periodic superstructures in thin crystals of hexagonal boron nitride using atomic-force microscopy and nano-infrared spectroscopy. The solitons form sub-surface hexagonal networks with periods of a few hundred nanometers. We analyze the topography and infrared contrast of these networks to obtain spatial distribution of local strain and its effect on the infrared-active phonons of hBN.

New aspects of boar semen freezing strategies.

Although cryopreserved boar semen has been available since 1975, a major breakthrough in commercial application has not yet occurred. There is ongoing research to improve sperm survival after thawing, to limit the damage occurring to spermatozoa during freezing, and to further minimize the number of spermatozoa needed to establish a pregnancy. Boar spermatozoa are exposed to lipid peroxidation during freezing and thawing, which causes damage to the sperm membranes and impairs energy metabolism. The addition of antioxidants or chelating agents (e.g. catalase, vitamin E, glutathione, butylated hydroxytoluene or superoxide dismutase) to the still standard egg-yolk based cooling and freezing media for boar semen, effectively prevented this damage. In general, final glycerol concentrations of 2-3% in the freezing media, cooling rates of -30 to -50 degrees C/min, and thawing rates of 1200-1800 degrees C/min resulted in the best sperm survival. However, cooling and thawing rates individually optimized for sub-standard freezing boars have substantially improved their sperm quality after cryopreservation. With deep intrauterine insemination, the sperm dose has been decreased from 6 to 1x10(9) spermatozoa without compromising farrowing rate or litter size. Minimizing insemination-to-ovulation intervals, based either on estimated or determined ovulation, have also improved the fertility after AI with cryopreserved boar semen. With this combination of different approaches, acceptable fertility with cryopreserved boar semen can be achieved, facilitating the use of cryopreserved boar semen in routine AI programs.

Utilization of frozen-thawed epididymal ram semen to preserve genetic diversity in Scrapie susceptible sheep breeds.

The European Union has introduced transmissible spongiform encephalopathy (TSE) resistance breeding programmes for several sheep breeds to cope with the genetic susceptibility to Scrapie infections. Due to the different allele frequencies among breeds, strong selection for ARR alleles is associated with a loss of genetic diversity in small populations and in larger populations with unfavourable ARR allele frequencies. To ensure maintenance of genetic diversity, an adhoc cryopreservation programme was initiated employing epididymal sperm from 109 rams representing 16 different breeds within one breeding season. Epididymal semen was chosen for this adhoc programme because time consuming training of rams for ejaculated semen collection via an artificial vagina was not possible. Prior to freezing, average sperm motility was 79.7% and acrosome integrity was 93.7%. After freezing, these levels were decreased to 60.5 and 72.8%, respectively. An insemination trial using frozen-thawed epididymal semen resulted in a lambing rate of 87.5%. Results show that this semen preservation method is robust and efficient and associated with high fertility. It may also be useful for other animal species.

The management of chronic tinnitus: comparison of an outpatient cognitive-behavioral group training to minimal-contact interventions.

OBJECTIVE: Using a randomized group design, the efficacy of an outpatient cognitive-behavioral Tinnitus Coping Training (TCT) was compared to two minimal-contact (MC) interventions. METHODS: TCT was conducted in a group format with 11 sessions (total n=43). One MC [MC-E (education), n=16] consisted of two group sessions in which education on tinnitus was presented and self-help strategies were introduced. The second MC [MC-R (relaxation), n=16] comprised four sessions. Besides education, music-supported relaxation was suggested as self-help strategy and audiotapes with relaxing music were provided. Furthermore, a waiting-list control group was installed (WC, n=20). Data were assessed at baseline (pretherapy) and at posttherapy period. Only TCT was additionally evaluated at a 6-month and a 12-month follow-up. Several outcome variables (e.g., awareness of tinnitus) were recorded in a tinnitus diary. Tinnitus coping and disability due to tinnitus were assessed by questionnaires. Subjective ratings of improvement were also requested from the patients. Furthermore, inventories of psychopathology were given to the patients. RESULTS: Findings reveal highly significant improvements in TCT in comparison to the control group (WC). MC interventions do not differ significantly from each other, but are superior to WC in a few domains of outcome. Outcome in TCT is somewhat superior to combined MC interventions in two domains of data, but not regarding disability reduction. Effect sizes, nevertheless, indicate distinct differences in degree of improvement, with TCT achieving the best results. CONCLUSIONS: A sequential scheme for the treatment of chronic tinnitus is discussed on the basis of cost-effectiveness considerations.

The management of chronic tinnitus--comparison of a cognitive-behavioural group training with yoga.

Two non-medical treatment strategies for chronic idiopathic tinnitus were evaluated in a randomized control group design. A cognitive-behavioural tinnitus coping training (TCT) was developed and compared to yoga and a self-monitoring control condition. Forty-three chronic tinnitus patients, were assessed at baseline, directly after therapy, and at 3 months follow-up. For evaluation, differential psychoacoustic variables were registered, a tinnitus diary as well as the Tinnitus Questionnaire and different measures of general well-being were used. Statistical analyses showed effects favouring the TCT treatment in comparison to the control and yoga treatment. The TCT-treated patients reported more satisfaction with the training than the yoga group. Participants in the self-monitoring control group were treated either by TCT or yoga after a waiting period. The outcome in this group was even better than in the experimental groups while yoga again showed rather poor effects.

[Medical care in large camp grounds--a report of experiences]. / Die medizinische Versorgung auf grossen Zeltlagern--ein Erfahrungsbericht.

This paper reports on the experiences gathered in respect of medical care during a ten-day youth camp with members of German girl guide and boy scout associations in the summer of 1988 comparising 6,000 youngsters. Large-scale tent camping of children and adolescents lasting for several days requires a costly and complicated infrastructure for self-support. A medical aid unit where patients can also be looked after on an inpatient basis if necessary, is mandatory if there are more than approximately 300 campers. There should be a doctor-participants ratio of 1:500 or 1:800 for "around-the-clock" availability of medical aid. One of the doctors in the medical team should be a surgeon or a doctor particularly skilled in minor surgery. Every doctor should have three medical assistants at his disposal. Cooperation with hospitals and practising physicians in the neighbourhood should be clarified and organised beforehand. The most frequently occurring diseases in the tent camp were injuries (36% of the patient material), infectious diseases (30%) often of a viral nature and physically conditioned noxae (sunburn, solar dermatitis, burns). About 8% of the patients had to be treated on an inpatient basis in the medical camp unit. Severe lesions or injuries were very rare, probably mainly thanks to the disciplined behaviour of the participants in the camp.

High-Resolution Infrared Fourier-Transform Spectroscopy and Rotational Constants of the nu4 Band of BrNO2.

For the first time, high-resolution infrared gas-phase absorption spectra of the BrNO2 molecule were recorded using a Fourier-transform spectrometer. In this paper, the nu4 bands of the 79BrNO2 and 81BrNO2 isotopomers around 1670 cm-1 are investigated. Although the spectra are highly congested, rotational and centrifugal distortion constants for the ground and v4 = 1 states of 79BrNO2 and 81BrNO2 were determined. The results show that BrNO2 is a planar molecule of C2nu symmetry and confirm predictions from a recent ab initio study. Copyright 1998 Academic Press.