Book Reviews

The legal profession is to be congratulated that men of the great erudition of Dean Wigmore and the editors associated with him are devoting themselves so unselfishly to the heavy labor of presenting in fitting English form the masterpieces of continental legal literature. Though much may be said about the insufficiency of translations as a basis of scholarly work in -any subject, the fact remains that the great bulk of the legal profession, even those of a scholarly habit of mind, have not the linguistic ability necessary to use the original sources of knowledge. On the other hand the need of knowledge of European law is a most insistent one. Our continual round of precedent-grinding, on the basis of the naive political philosophy of the eighteenth century, has long since proved its inadequacy. The profession, or at least the better part of it, is beginning to look for some enlarging and enfranchising ideas, and is ready to welcome them from any source. Though much remains to be done in The detail of working out the history of our own system, we nevertheless have a solid basis of historical knowledge of the common law, thanks to the investigations of our scholars, English and American, in that field: The careful study of cases and the building up of our admirable series of casebooks have made the results of these historical investigations available to the student of our day. The next step forward must be to enlarge the basis of our scholarship by comparative study of other systems in their historical development and to get new points of view as to the meaning and tendency of legal concepts from the legal philosophies of other countries. The translation will give to the average member of the profession and to the ordinary student of law a chance to participate in or at least to keep up with the progress in the comparative and philosophic fields, and will serve the same \u27purpose in this new movement that the casebooks have served in interpreting and passing on the historical knowledge of our own system

Perfect interferenceless absorption at infrared frequencies by a van der Waals crystal

Citation: Baranov, D. G., Edgar, J. H., Hoffman, T., Bassim, N., & Caldwell, J. D. (2015). Perfect interferenceless absorption at infrared frequencies by a van der Waals crystal. Physical Review B, 92(20), 6. doi:10.1103/PhysRevB.92.201405Traditionally, efforts to achieve perfect absorption have required the use of complicated metamaterial-based structures as well as relying on destructive interference to eliminate back reflections. Here, we have demonstrated both theoretically and experimentally that such perfect absorption can be achieved using a naturally occurring material, hexagonal boron nitride (hBN) due to its high optical anisotropy without the requirement of interference effects to absorb the incident field. This effect was observed for p-polarized light within the mid-infrared spectral range, and we provide the full theory describing the origin of the perfect absorption as well as the methodology for achieving this effect with other materials. Furthermore, while this is reported for the uniaxial crystal hBN, this is equally applicable to biaxial crystals and more complicated crystal structures. Interferenceless absorption is of fundamental interest to the field of optics; moreover, such materials may provide additional layers of flexibility in the design of frequency selective surfaces, absorbing coatings, and sensing devices operating in the infrared

Characterization of bulk hexagonal boron nitride single crystals grown by the metal flux technique

The optical and physical properties of hexagonal boron nitride single crystals grown from a molten metal solution are reported. The hBN crystals were grown by precipitation from a nickel-chromium flux with a boron nitride source, by slowly cooling from 1500 °C at 2-4°C/h under a nitrogen flow at atmospheric pressure. The hBN crystals formed on the surface of the flux with an apparent crystal size up to 1 to 2 mm in diameter. Individual grains were as large as 100-200 µm across. Typically, the flakes removed from the metal were 6 to 20 µm thick. Optical absorption measurements suggest a bandgap of 5.8 eV by neglecting the binding energy of excitons in hBN. The highest energy photoluminescence peak was at 5.75 eV at room temperature. The hBN crystals typically had a pit density of 5 x 10⁶ cm⁻² after etching in a molten eutectic mixture of potassium hydroxide and sodium hydroxide. The quality of these crystals suggests they are suitable as substrates for two dimensional materials such as graphene and gallium nitride based devices

Nature of exciton transitions in hexagonal boron nitride

Citation: Li, J., Cao, X. K., Hoffman, T. B., Edgar, J. H., Lin, J. Y., & Jiang, H. X. (2016). Nature of exciton transitions in hexagonal boron nitride. Applied Physics Letters, 108(12), 4. doi:10.1063/1.4944696In contrast to other III-nitride semiconductors GaN and AlN, the intrinsic (or free) exciton transition in hexagonal boron nitride (h-BN) consists of rather complex fine spectral features (resolved into six sharp emission peaks) and the origin of which is still unclear. Here, the free exciton transition (FX) in h-BN bulk crystals synthesized by a solution method at atmospheric pressure has been probed by deep UV time-resolved photoluminescence (PL) spectroscopy. Based on the separations between the energy peak positions of the FX emission lines, the identical PL decay kinetics among different FX emission lines, and the known phonon modes in h-BN, we suggest that there is only one principal emission line corresponding to the direct intrinsic FX transition in h-BN, whereas all other fine features are a result of phonon-assisted transitions. The identified phonon modes are all associated with the center of the Brillouin zone. Our results offer a simple picture for the understanding of the fundamental exciton transitions in h-BN. (C) 2016 AIP Publishing LLC

DIFFERENTIAL EFFECTS OF VARYING DOSES OF DIETARY NITRATE ON MUSCLE FUNCTION AND BLOOD PRESSURE IN OLDER SUBJECTS

We have recently demonstrated that dietary nitrate, a source of nitric oxide via the enterosalivary pathway, can improve muscle contractile function in healthy older men and women. Nitrate ingestion has also been shown to reduce blood pressure in older individuals. However, the optimal dose for eliciting these beneficial effects is unknown. We therefore performed a randomized, double-blind, crossover study to determine the effects of ingesting 3.3 mL/kg of beetroot juice (BRJ) containing 0, 212, or 425 µmol/kg of nitrate in six healthy older (age 69±3 y) subjects. Maximal knee extensor speed (Vmax) and power (Pmax) were measured 2 h after BRJ ingestion using isokinetic dynamometry; blood pressure was monitored periodically throughout each study. Mean arterial pressure (in mmHg) was lower (P<0.05) after the high (80±4) vs. the low (84±3) or placebo (88±2) doses. Vmax (in rad/s), however, was higher (P<0.05) after the low dose (11.7±0.8), but not the high dose (10.8±1.0), compared to the placebo (10.5±1.0). Pmax (in W/kg) also tended to be higher (P=0.11) in the low (3.9±0.5) compared to the placebo (3.7±0.5) or high (3.7±0.5) trials. Five out of six subjects achieved a higher Vmax and Pmax after the low vs. the high dose. We conclude that dietary nitrate has differential effects on muscle function and blood pressure in older individuals. A high dose of nitrate intake further lowers blood pressure but does not enhance muscle contractility as much as a lower dose. Supported by Indiana University Purdue University Indianapolis and by the NIA (R21 AG053606)

Physical performance and glycemic control under SGLT-2-inhibitors in patients with type 2 diabetes and established atherosclerotic cardiovascular diseases or high cardiovascular risk (PUSH): Design of a 4-week prospective observational study.

Background Type 2 diabetes (T2D) is associated with limitation in physical performance. Results from animal studies report enhancement of physical performance in T2D rodents treated with sodium glucose cotransporter 2 inhibitors (SGLT2is). However, in human patients with T2D and established atherosclerotic cardiovascular disease (ASCVD) or high cardiovascular risk, the impact of guideline directed SGLT2i medication on physical performance has not been sufficiently examined. Objectives The main objectives of this study are thus firstly, to assess the changes in physical performance after 4 weeks of exercise therapy in patients with established ASCVD or high cardiovascular risk categorized into three groups according to their glycemic control at baseline. Secondly, to investigate the association of glycemic control at baseline and new guideline directed antidiabetic treatment (inadequate glycemic control and diabetes + new SGLT2i vs. adequate glycemic control and diabetes vs. no diabetes) with change in physical performance. Methods and design This is a 4-week prospective observational study of 450 participants with established ASCVD or high cardiovascular risk with or without T2D and without previous SGLT2i medication undergoing exercise therapy during inpatient rehabilitation in a single center in Switzerland. Upon admission, participants are categorized into 3 groups of 150 participants each according to their glycemic control. Group I consisting of participants with inadequately controlled T2D defined as mean fasting plasma glucose (FPG) of ≥7 mmol/L, who are consequently administered new treatment with an SGLT2i. Group II comprises of participants with adequately controlled T2D with mean FPG of <7 mmol/L requiring no antidiabetic medication change. Group III consists of participants with no diabetes and mean FPG of ≤ 5.5 mmol/L. Primary outcomes are 6-min walk distance and rate of perceived exertion. Secondary outcomes are echocardiographic parameters (left ventricular mass index; global longitudinal strain average; end-diastolic volume), fatigue, muscle, metabolic, and anthropometric measures. Ethics and dissemination This study is conducted in accordance with the Declaration of Helsinki with ethical approval from the Cantonal Ethical Commission of Bern, Switzerland. The results will be published in a peer-reviewed journal. The implementation and reporting will be according to the SPIRIT guidelines. Study protocol registration https://www.clinicaltrials.gov/, identifier: NCT03422263

Single photon emission from plasma treated 2D hexagonal boron nitride

© 2018 The Royal Society of Chemistry. Artificial atomic systems in solids are becoming increasingly important building blocks in quantum information processing and scalable quantum nanophotonic networks. Amongst numerous candidates, 2D hexagonal boron nitride has recently emerged as a promising platform hosting single photon emitters. Here, we report a number of robust plasma and thermal annealing methods for fabrication of emitters in tape-exfoliated hexagonal boron nitride (hBN) crystals. A two-step process comprising Ar plasma etching and subsequent annealing in Ar is highly robust, and yields an eight-fold increase in the concentration of emitters in hBN. The initial plasma-etching step generates emitters that suffer from blinking and bleaching, whereas the two-step process yields emitters that are photostable at room temperature with emission wavelengths greater than ∼700 nm. Density functional theory modeling suggests that the emitters might be associated with defect complexes that contain oxygen. This is further confirmed by generating the emitters via annealing hBN in air. Our findings advance the present understanding of the structure of quantum emitters in hBN and enhance the nanofabrication toolkit needed to realize integrated quantum nanophotonic circuits

HIF-1–dependent repression of equilibrative nucleoside transporter (ENT) in hypoxia

Extracellular adenosine (Ado) has been implicated as central signaling molecule during conditions of limited oxygen availability (hypoxia), regulating physiologic outcomes as diverse as vascular leak, leukocyte activation, and accumulation. Presently, the molecular mechanisms that elevate extracellular Ado during hypoxia are unclear. In the present study, we pursued the hypothesis that diminished uptake of Ado effectively enhances extracellular Ado signaling. Initial studies indicated that the half-life of Ado was increased by as much as fivefold after exposure of endothelia to hypoxia. Examination of expressional levels of the equilibrative nucleoside transporter (ENT)1 and ENT2 revealed a transcriptionally dependent decrease in mRNA, protein, and function in endothelia and epithelia. Examination of the ENT1 promoter identified a hypoxia inducible factor 1 (HIF-1)–dependent repression of ENT1 during hypoxia. Using in vitro and in vivo models of Ado signaling, we revealed that decreased Ado uptake promotes vascular barrier and dampens neutrophil tissue accumulation during hypoxia. Moreover, epithelial Hif1α mutant animals displayed increased epithelial ENT1 expression. Together, these results identify transcriptional repression of ENT as an innate mechanism to elevate extracellular Ado during hypoxia