Factors Influencing the Exterior Design of Autonomous Passenger Drones: Literature Review

Electric vertical take-off and landing aircraft (eVTOLs) have been accessed on various configurations over the past decade. This literature review deals with the issue of determining the appropriate design for an Autonomous Passenger Drone (APD). APDs have been compared with VTOLs on their pros and cons. The authors analysed aerodynamics and propulsion systems of multiple APDs. Further, the comparative analysis aids in designing the best framework for the exterior form of APDs based on human capacity, flying technology, fuel type, travel distance, door type, size, material, safety, cost, etc. © The Author(s), 2022

Thermoelectric Cooling to Survive Commodity DRAMs in Harsh Environment Automotive Electronics

Today, more and more commodity hardware devices are used in safety-critical applications, such as advanced driver assistance systems in automotive. These applications demand very high reliability of electronic components even in adverse environmental conditions, such as high temperatures. Ensuring the reliability of microelectronic components is a major challenge at these high temperatures. The computing systems of these applications rely on DRAMs as working memory, which are built upon bit cells that store charges in capacitors. These commodity DRAMs are optimized for cost per bit and not for high reliability. Thus, very high temperatures impose an enormous challenge for commodity DRAMs as the data retention time and reliability decrease largely, affecting the data correctness. Data correctness can be ensured up to certain temperatures by increasing the refresh rate to counterbalance the retention time reduction. However, this severely degrades the access latencies and the usable DRAM bandwidth. To overcome these limitations, we present for the first time a Thermoelectric Cooling (TEC) solution for commodity DRAMs in harsh-environments, such as automotive. Our TEC solution enables the use of commodity off-the-shelf DRAMs in safety-critical applications by reducing the temperature conditions to a range where they can operate reliably. This TEC solution is applied a posteriori to the DRAM chips without using high-cost package solutions. Thus, it maintains the low-cost targets of such devices, improves the reliability, and at the same time, counterbalances the adverse effects of increasing the refresh rate. To quantitatively evaluate the benefits of TEC on commodity DRAMs in harsh-environments, we performed system-level evaluations with several applications backed up by the measured data on commodity DRAMs. Our experimental results, using accurate multi-physics simulations that employ finite element method, demonstrate that the TEC-based cooling ensures that the maxim..

Effect of semi-solid forging on microstructure and mechanical properties of in-situ cast Al-Cu-TiB2 composites

The present work deals with the effect of semisolid processing on microstructure and mechanical properties of Al-4.5% Cu – 5% TiB2 in-situ cast composites. The composite was prepared by flux assisted synthesis in which TiB2 particles were formed in-situ through an exothermic reaction between K2TiF6 and KBF4 halide salts. Al-4.5 wt% Cu alloy and Al-4.5% Cu-5% TiB2 composite samples were forged in semisolid state with 0.3 vol fraction of liquid. Semisolid forging was carried out for two forge reductions (30% and 50% forge reductions). Microstructure studies show that the semi-solid forging results in uniform distribution of TiB2 particles and Al2Cu particles in the composite. Further, TiB2 particles play a dual role as grain refiners as well as reinforcements of composites. EBSD and nano indentation studies shows that semisolid forging results in dynamic recrystallization of grains in the composite with significant grain refinement which leads to a marked increase in hardness and elastic modulus of the alloy as well as the composite

Sensory and chemical evaluation of laboratory ensiled hybrid Napier grass prepared using Lactobacillus plantarum and propionic acid as additives

The present study was undertaken to evaluate silage made from hybrid Napier grass (Pennisetum purpureum) ensiled in the laboratory using various additives with regard to sensory as well as chemical characteristics. Four different silages were prepared viz., grass ensiled without additives (GS) as control, and grass silage with Lactobacillus plantarum at 1 x 105 CFU per gram of fresh forage (GSL), grass silage with propionic acid at the rate 0.45 kg per ton of fodder (GSA), and grass silage with combination of Lactobacillus plantarum (1 x 105 CFU per gram of fresh forage) and propionic acid (0.45 kg per ton of fodder) (GSLA) in triplicates. One from each triplicate was opened on 21, 30 and 45 days of ensiling and was evaluated for sensory (colour, aroma, presence or absence of extraneous matter) and chemical (pH, lactic acid, proximate analysis and fibre fractions) characteristics. From the overall results, it could be concluded that hybrid Napier grass, ensiled for 21 days using L. plantarum was effective in preserving its nutritive value

RRAMSpec: A Design Space Exploration Framework for High Density Resistive RAM

Resistive RAM (RRAM) is a promising emerging Non-Volatile Memory candidate due to its scalability and CMOS compatibility, which enables the fabrication of high density RRAM crossbar arrays in Back-End-Of-Line CMOS processes. Fast and accurate architectural models of RRAM crossbar devices are required to perform system level design space explorations of new Storage Class Memory (SCM) architectures using RRAM e.g. Non-Volatile-DIMM-P (NVDIMM-P). The major challenge in architectural modeling is the trade-off between accuracy and computing intensity. In this paper we present RRAMSpec, an architecture design space exploration framework, which enables fast exploration of various architectural trade-offs in designing high density RRAM devices, at accuracy levels close to circuit level simulators. The framework estimates silicon area, timings, and energy for RRAM devices. It outperforms state-of-the-art RRAM modeling tools by conducting architectural explorations at very high accuracy levels within few seconds of execution time. Our evaluations show various trade-offs in designing RRAM crossbar arrays with respect to array sizes, write time and write energy. Finally we present the influence of technology scaling on different RRAM design trade-offs

Biodegradable microparticulate drug delivery system of diltiazem HCl

The efficacy of a drug in a specific application requires the maintenance of appropriate drug blood level concentration during a prolonged period of time. Controlled release delivery is available for many routes of administration and offers many advantages (as microparticles and nanoparticles) over immediate release delivery. These advantages include reduced dosing frequency, better therapeutic control, fewer side effects, and, consequently, these dosage forms are well accepted by patients. Advances in polymer material science, particle engineering design, manufacture, and nanotechnology have led the way to the introduction of several marketed controlled release products and several more are in pre-clinical and clinical development. The objective of this work is to prepare and evaluate diltiazem HCl loaded albumin microparticles using a factorial design. Albumin (natural polymer) microparticles were prepared by emulsion heat-stabilization method. Selected formulations were characterized for their entrapment efficiency, particle size, surface morphology, and release behavior. Analysis of variance for entrapment efficiency indicates that entrapment efficiency is best fitted to a response surface linear model. Surface morphology was studied by scanning electron microscopy. Scanning electron microscopy of the microparticles revealed a spherical, nonporous and uniform appearance, with a smooth surface. The geometric mean diameter of the microparticles was found to be 2-9 µm, which more than 75% were below 3.5 µm and drug incorporation efficiency of 59.74 to 72.48% (w/w). In vitro release profile for formulations containing diltiazem HCl loaded BSA microparticles with heat stabilization technique shows slow controlled the release of the drug up to 24 hours. The release pattern was biphasic, characterized by an initial burst effect followed by a slow release. All selected microparticles exhibited a prolonged release for almost 24 hours. On comparing regression-coefficient (r²) values for Hixson Crowel, Higuchi and Peppas kinetic models, different batches of microparticles showed Fickian, non-Fickian, and diffusion kinetics. The release mechanism was regulated by D:P ratio. From the statistical analysis it was observed that as the drug:polymer (D:P) ratio increased, there was a significant increase in the encapsulation efficiency. Based on the particle size, entrapment efficiency and physical appearance, DTM-3 formulations were selected for in vivo release study and stability study. The in vivo result of drug loaded microparticles showed preferential drug targeting to liver followed by lungs, kidneys and spleen. Stability studies showed that maximum drug content and closest in vitro release to initial data were found in the formulation stored at 4 ºC. In present study, diltiazem HCl loaded BSA microparticles were prepared and targeted to various organs to satisfactory level and were found to be stable at 4 ºC.A eficácia terapêutica de um fármaco depende da manutenção de seu nível plasmático adequado em determinado intervalo de tempo. Nesse sentido, a liberação modificada de fármacos está disponível em muitas vias de administração e oferece muitas vantagens (como micropartículas e nanopartículas) quando comparada às formulações de liberação imediata. Essas vantagens incluem reduzida frequência da dosagem, melhor controle terapêutico e menos efeitos colaterais. Assim sendo, esses produtos apresentam maior aceitação pelos pacientes. Os avanços na ciência dos materiais, na engenharia das partículas, em manufatura e em nanotecnologia permitiram a introdução no mercado de vários produtos de liberação modificada e vários outros se encontram em desenvolvimento pré-clínico e clínico. O objetivo do presente trabalho foi preparar e avaliar o fármaco cloridrato de diltiazem associado a micropartículas de albumina utilizando planejamento fatorial. As micropartículas de albumina, um polímero natural, foram preparadas por método de emulsão empregando estabilização por calor. As formulações selecionadas foram caracterizadas no que se refere à sua eficiência de encapsulamento, tamanho médio de partículas, morfologia de superfície e perfil de liberação do fármaco. A análise de variância relativa à eficiência de encapsulamento indicou superfície de resposta linear. Com referência à morfologia superficial, essa foi avaliada empregando microscopia eletrônica de varredura. Essa análise revelou micropartículas esféricas, não porosas e de aparência uniforme, com superfície lisa. O diâmetro médio das micropartículas foi entre 2 e 9 µm, sendo que mais de 75% das micropartículas se apresentaram abaixo de 3,5 µm. Além disso, a eficiência de encapsulamento foi entre 59,74 e 72,48%. Quanto ao ensaio para avaliação do perfil de liberação in vitro do fármaco associado às micropartículas, as formulações apresentaram liberação lenta até 24 horas. O comportamento foi caracterizado por liberação inicial (efeito burst) seguida por liberação lenta. Todas as fórmulas selecionadas apresentaram liberação prolongada por aproximadamente 24 horas. Na comparação entre os valores de coeficientes de regressão (R²), os modelos propostos por Hixson Crowel, Higuchi e Peppas, para diferentes formulações de micropartículas, demonstraram cinética de liberação de acordo com modelo Fickiano e não-Fickiano. O mecanismo de liberação do fármaco foi regulado pela razão entre o fármaco e o polímero. A análise estatística revelou significativo aumento da eficiência de encapsulamento quando essa razão aumentou. As avaliações relativas à análise dimensional das micropartículas, à eficiência de encapsulamento do fármaco e à morfologia permitiram a seleção da formulação DTM-3 para os ensaios de liberação in vivo e para o estudo da estabilidade. O ensaio de liberação in vivo do fármaco associado às micropartículas demonstrou sítio-alvo preferencial no fígado, seguido pelos pulmões rins e baço. No presente estudo, as micropartículas de albumina contendo cloridrato de diltiazem foram adequadamente preparadas e orientadas satisfatoriamente para vários órgãos. Além disso, a formulação selecionada apresentou estabilidade físico-química a 4 ºC

Selection-Free Zinc-Finger Nuclease Engineering by Context-Dependent Assembly (CoDA)

Engineered zinc-finger nucleases (ZFNs) enable targeted genome modification. Here we describe Context-Dependent Assembly (CoDA), a platform for engineering ZFNs using only standard cloning techniques or custom DNA synthesis. Using CoDA ZFNs, we rapidly altered 20 genes in zebrafish, Arabidopsis, and soybean. The simplicity and efficacy of CoDA will enable broad adoption of ZFN technology and make possible large-scale projects focused on multi-gene pathways or genome-wide alterations

Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

The impact of immediate breast reconstruction on the time to delivery of adjuvant therapy: the iBRA-2 study

Background: Immediate breast reconstruction (IBR) is routinely offered to improve quality-of-life for women requiring mastectomy, but there are concerns that more complex surgery may delay adjuvant oncological treatments and compromise long-term outcomes. High-quality evidence is lacking. The iBRA-2 study aimed to investigate the impact of IBR on time to adjuvant therapy. Methods: Consecutive women undergoing mastectomy ± IBR for breast cancer July–December, 2016 were included. Patient demographics, operative, oncological and complication data were collected. Time from last definitive cancer surgery to first adjuvant treatment for patients undergoing mastectomy ± IBR were compared and risk factors associated with delays explored. Results: A total of 2540 patients were recruited from 76 centres; 1008 (39.7%) underwent IBR (implant-only [n = 675, 26.6%]; pedicled flaps [n = 105,4.1%] and free-flaps [n = 228, 8.9%]). Complications requiring re-admission or re-operation were significantly more common in patients undergoing IBR than those receiving mastectomy. Adjuvant chemotherapy or radiotherapy was required by 1235 (48.6%) patients. No clinically significant differences were seen in time to adjuvant therapy between patient groups but major complications irrespective of surgery received were significantly associated with treatment delays. Conclusions: IBR does not result in clinically significant delays to adjuvant therapy, but post-operative complications are associated with treatment delays. Strategies to minimise complications, including careful patient selection, are required to improve outcomes for patients