Broadband PureB Ge-on-Si photodiodes

Broadband PureB Ge-on-Si photodiodes were fabricated by in-situ capping of n-type Ge-islands grown by chemical-vapor deposition on Si with a 10-nm-thick pure boron layer. Using deposition temperatures from 575°C - 700°C, the B-layer forms p+-like anodes with nm-shallow junctions and low dark currents, enabling close to ideal responsivities of 0.13, 0.37, 0.48, and 0.19 A/W at wavelengths 406, 670, 1310 and 1550 nm, respectively.</p

The Nature of Persistent Conformational Chirality, Racemization Mechanisms, and Predictions in Diarylether Heptanoid Cyclophane Natural Products

Restricted rotations of chemical bonds can lead to the presence of persistent conformational chirality in molecules 10 lacking stereocenters. We report the development of first-ofa- kind predictive rules that enable identification of conformational chirality and prediction of racemization barriers in the diarylether heptanoid (DAEH) natural products that do not possess stereocenters. These empirical 15 rules-of-thumb are based on quantum mechanical computations (SCS-MP2/∞//B3LYP/6-31G*/PCM) of racemization barriers of four representative DAEHs. Specifically, the local symmetry of ring B and the E/Z configuration of the vinylogous acid/ester are critical in 20 determining conformational chirality in the DAEH natural product family. Molecular chirality is of paramount importance to chemistry, biology, and medicine. Small molecules that are chiral by virtue of restricted rotations (atropisomerism), or conformational 25 chirality, are an underdeveloped territory with the potential for new developments of chiral ligands, medicinal compounds, catalysts, and materials. At present, there are no known methods to predict the presence of persistent conformational chirality in these compounds based solely on their molecular architecture 30 without resorting to total synthesis. Specifically in this report, we have developed predictive rules-of-thumb for the chiral properties of all members in a family of cyclophane natural products called the diarylether heptanoids (DAEHs). Additionally, we elucidate the atomistic and energetic details 35 related to the racemizations.This is an author's peer-reviewed final manuscript, as accepted by the publisher

MIDA boronates are hydrolysed fast and slow by two different mechanisms

MIDA boronates (N-methylimidodiacetic boronic acid esters) serve as an increasingly general platform for small-molecule construction based on building blocks, largely because of the dramatic and general rate differences with which they are hydrolysed under various basic conditions. Yet the mechanistic underpinnings of these rate differences have remained unclear, which has hindered efforts to address the current limitations of this chemistry. Here we show that there are two distinct mechanisms for this hydrolysis: one is base mediated and the other neutral. The former can proceed more than three orders of magnitude faster than the latter, and involves a rate-limiting attack by a hydroxide at a MIDA carbonyl carbon. The alternative 'neutral' hydrolysis does not require an exogenous acid or base and involves rate-limiting B-N bond cleavage by a small water cluster, (H2O)n. The two mechanisms can operate in parallel, and their relative rates are readily quantified by (18)O incorporation. Whether hydrolysis is 'fast' or 'slow' is dictated by the pH, the water activity and the mass-transfer rates between phases. These findings stand to enable, in a rational way, an even more effective and widespread utilization of MIDA boronates in synthesis

Perturbed myoepithelial cell differentiation in BRCA mutation carriers and in ductal carcinoma in situ.

Myoepithelial cells play key roles in normal mammary gland development and in limiting pre-invasive to invasive breast tumor progression, yet their differentiation and perturbation in ductal carcinoma in situ (DCIS) are poorly understood. Here, we investigated myoepithelial cells in normal breast tissues of BRCA1 and BRCA2 germline mutation carriers and in non-carrier controls, and in sporadic DCIS. We found that in the normal breast of non-carriers, myoepithelial cells frequently co-express the p63 and TCF7 transcription factors and that p63 and TCF7 show overlapping chromatin peaks associated with differentiated myoepithelium-specific genes. In contrast, in normal breast tissues of BRCA1 mutation carriers the frequency of p63+TCF7+ myoepithelial cells is significantly decreased and p63 and TCF7 chromatin peaks do not overlap. These myoepithelial perturbations in normal breast tissues of BRCA1 germline mutation carriers may play a role in their higher risk of breast cancer. The fraction of p63+TCF7+ myoepithelial cells is also significantly decreased in DCIS, which may be associated with invasive progression

A large-volume academic center retrospective audit of the temporal evolution of immediate breast reconstruction protocols and the effect on breast prosthetic infection

Complications of tissue expanders (TEs) in breast reconstruction are challenging. We sought to identify TE infection risks and acellular dermal matrix (ADM) and infection control protocol impacts on infection in a longitudinal study. We retrospectively analyzed TE/implant reconstructions in 2004 (no ADM), 2009 (TE and ADM), 2013 (TE, ADM, and infection control protocol), and 2015 (TE, ADM, and infection control protocol). We assessed demographic, disease, and operative factors and analyzed rates of seroma, hematoma, skin necrosis, and infection. Statistical analysis, including simple and multivariable logistic regression, was performed using Stata v13.1. 478 TEs were placed in 324 women, with a 30% overall patient complication rate (23% of breasts). A total of 14% of TEs became infected. Although unadjusted analysis showed no ADM and infection association (p = 0.269), multivariable logistic regression showed a significant association with more infections (OR: 3.21; 95% CI: 1.13–9.313; p = 0.029). The infection control protocol decreased infections by 28% (16% in 2009 vs 11% in 2013); however, this did not achieve statistical significance (unadjusted p = 0.192, adjusted p = 0.156). Seroma (p < 0.001), older age (p = 0.040), larger mastectomy volume (p = 0.001), smoking (p = 0.037), BMI (p < 0.001), vascular disorders (p = 0.007), and hypertension (p < 0.001) significantly increased infections. Identifiable risks exist in TE/implant breast reconstruction. ADM infection risk may mitigate some potential benefits. Anti-infection protocols may reduce infections, and further investigation may reveal the most effective prophylactic strategies. Absence of major changes in complications over time supports validity of studies examining large numbers of despite evolution of techniques

Efficacy of neurostimulation across mental disorders: systematic review and meta-analysis of 208 randomized controlled trials

Non-invasive brain stimulation (NIBS), including transcranial magnetic stimulation (TMS), and transcranial direct current stimulation (tDCS), is a potentially effective treatment strategy for a number of mental conditions. However, no quantitative evidence synthesis of randomized controlled trials (RCTs) of TMS or tDCS using the same criteria including several mental conditions is available. Based on 208 RCTs identified in a systematic review, we conducted a series of random effects meta-analyses to assess the efficacy of NIBS, compared to sham, for core symptoms and cognitive functioning within a broad range of mental conditions. Outcomes included changes in core symptom severity and cognitive functioning from pre- to post-treatment. We found significant positive effects for several outcomes without significant heterogeneity including TMS for symptoms of generalized anxiety disorder (SMD = −1.8 (95% CI: −2.6 to −1), and tDCS for symptoms of substance use disorder (−0.73, −1.00 to −0.46). There was also significant effects for TMS in obsessive-compulsive disorder (−0.66, −0.91 to −0.41) and unipolar depression symptoms (−0.60, −0.78 to −0.42) but with significant heterogeneity. However, subgroup analyses based on stimulation site and number of treatment sessions revealed evidence of positive effects, without significant heterogeneity, for specific TMS stimulation protocols. For neurocognitive outcomes, there was only significant evidence, without significant heterogeneity, for tDCS for improving attention (−0.3, −0.55 to −0.05) and working memory (−0.38, −0.74 to −0.03) in individuals with schizophrenia. We concluded that TMS and tDCS can benefit individuals with a variety of mental conditions, significantly improving clinical dimensions, including cognitive deficits in schizophrenia which are poorly responsive to pharmacotherapy