Triclinic form of bis­{di-μ-hydroxidobis[fac-aqua­tribromido­tin(IV)]} hepta­hydrate

The asymmetric unit of the title hydrate, 2[Sn(H2O)2(OH)2Br6]·7H2O, comprises two [Br3(H2O)Sn(μ-OH)2SnBr3(OH2)] units, but three independent mol­ecules as two of these are disposed about inversion centres, and seven water mol­ecules. In common with the monoclinic polymorph [Howie et al. (2005 ▶). Inorg. Chim. Acta, 358, 3283–3286], each of the dinuclear species features a central Sn2O2 core, distorted octa­hedral Sn atom geometries defined by a Br3O3 donor set, and an anti-disposition of the coordinated water mol­ecules. In the crystal, Oh—H⋯Ow, Oa—H⋯Ow, Ow—H⋯Ow, and Ow—H⋯Br (h = hydroxyl, a = aqua, w = water) hydrogen-bonding inter­actions generate a three-dimensional network

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

The Role of Damping in the Suppression of Parametric Resonances in Nonlinear Systems

Parametrically excited systems are not uncommon in the many structures and systems built today. Classical analysis shows that the presence of viscous damping in a linear system does not limit the infinite amplitude of the parametric resonance. In this paper we investigate the role of damping in the suppression of both fundamental and principal parametric resonances in nonlinear systems. The results show that critical values of damping are required to suppress a parametric resonance. In some cases, the nonlinearity causes a multivalued response that allows nontrivial responses to exist at levels of damping that exceed the critical threshold of damping for stability predicted by linear theory. For small values of damping, chaotic responses were observed

Enhanced Huffman Coded OFDM with index modulation

In this paper, we propose an enhanced Huffman coded orthogonal frequency-division multiplexing with index modulation (EHC-OFDM-IM) scheme. The proposed scheme is capable of utilizing all legitimate subcarrier activation patterns (SAPs) and adapting the bijective mapping relation between SAPs and leaves on a given Huffman tree according to channel state information (CSI). As a result, a dynamic codebook update mechanism is obtained, which can provide more reliable transmissions. We take the average block error rate (BLER) as the performance evaluation metric and approximate it in closed form when the transmit power allocated to each subcarrier is independent of channel states. Also, we propose two CSI-based power allocation schemes with different requirements for computational complexity to further improve the error performance. Subsequently, we carry out numerical simulations to corroborate the error performance analysis and the proposed dynamic power allocation schemes. By studying the numerical results, we find that the depth of the Huffman tree has a significant impact on the error performance when the SAP-to-leaf mapping relation is optimized based on CSI. Meanwhile, through numerical results, we also discuss the trade-off between error performance and data transmission rate and investigate the impacts of imperfect CSI on the error performance of EHC-OFDM-IM