Investigation of thermoelectric properties of cadmium selenide CdnSen (n= 7, 11, 13) molecular junctions: a DFT study.

CONTEXT: The thermoelectric properties of cadmium selenide (CdnSen) molecular junctions (n = 7, 11, 13) were investigated before and after adding hydrogen atoms. The effects of hydrogen passivation on the transmission and thermopower curves were analyzed. CdSe-diamantane (Cd7Se7) and CdSe-tetramantane (Cd11Se11) junctions exhibited the best thermoelectric performance due to their low surface reconstruction energy, which is attributed to the number of dangling and unsaturated bonds. This study guides the design of new molecular junctions with desired thermoelectric properties. METHOD: The electrical and thermal properties of cadmium selenide (CdnSen) molecular junctions (n = 7, 11, 13) were investigated using a ballistic quantum transport method based on the non-equilibrium Green's function (NEGF) approach. Thermoelectric properties were calculated for the molecular junctions with different structures before and after hydrogen passivation. Density functional theory (DFT) calculations were performed at the B3LYP level with the 3-21G basis set for the Cd atoms and the 6-31G** basis set for the Se atoms. The SIESTA and GOLLUM codes were used to study the effect of changing the shape and size of each structure on its electrical and thermal characteristics.

Physiological impacts on construction workers under extremely hot and humid weather.

PURPOSE: Construction worker health and safety is a primary concern for construction companies and researchers. Arabian Gulf region, like Saudi Arabia, has been experiencing extremely hot and humid (EHH) weather, which directly affects construction workers' health and safety. This study aims to address the problem of EHH weather conditions and their impacts on construction workers' physiological status. METHODS: This study assesses the impacts of EHH weather on construction workers' physiological status through the measurement of workers' physical body parameters (age, height, and weight); type of activities; and assigned tasks. Thirty-five multinational workers participated in the measurements, which were conducted in real construction site conditions A quantitative analysis was then applied to quantify the physiological impacts of the weather conditions. Several hypotheses were tested to identify the significant impacts of individual and working aspects on the workers' physiological responses. RESULTS AND CONCLUSION: The results provide empirical evidence that the recorded Heart Rate (HR) exceeded the acceptable physiological zones for construction workers exposed to extremely hot and humid weather conditions. Physical body parameters, work activities, and worker status significantly influence construction workers' physiological responses. This study recommends adopting a continuous monitoring approach as an early warning system under extremely hot and humid weather conditions.

National Clinical Guidance for the Management of Cardiovascular Intervention in the COVID-19 Pandemic: From Bangladesh Society of Cardiovascular Interventions (BSCI).

Since the first recorded case of SARS-CoV-2 in Bangladesh on 8th March 2020, COVID-19 has spread widely through different regions of the country, resulting in a necessity to re-evaluate the delivery of cardiovascular services, particularly procedures pertaining to interventional cardiology in resource-limited settings. Given its robust capacity for human-to-human transmission and potential of being a nosocomial source of infection, the disease has specific implications on healthcare systems and health care professionals faced with performing essential cardiac procedures in patients with a suspected or confirmed diagnosis of COVID-19. The limited resources in terms of cardiac catheterization laboratories that can be designated to treat only COVID positive patients are further compounded by the additional challenges of unavailability of widespread rapid testing on-site at tertiary cardiac hospitals in Bangladesh. This document prepared for our nation by the Bangladesh Society of Cardiovascular Interventions (BSCI) is intended to serve as a clinical practice guideline for cardiovascular health care professionals, with a focus on modifying standard practice of care during the COVID-19 pandemic, in order to ensure continuation of adequate and timely treatment of cardiovascular emergencies avoiding hospital-based transmission of SARS-COV-2 among healthcare professionals and the patients. This is an evolving document based on currently available global data and is tailored to healthcare systems in Bangladesh with particular focus on, but not limited to, invasive cardiology facilities (cardiac catheterization, electrophysiology & pacing labs). This guideline is limited to the provision of cardiovascular care, and it is expected that specific targeted pharmaco-therapeutics against SARS-CoV-2 be prescribed as stipulated by the National Guidelines on Clinical Management of Corona virus Disease 2019 (COVID-19) published by the Director General of Health Services, Ministry of Health and Family Welfare of Bangladesh.

Use of Ultra Wide Band Real-Time Location System on Construction Jobsites: Feasibility Study and Deployment Alternatives.

Ultra wide band (UWB)-based real-time location systems (RTLSs) have been widely adopted in the manufacturing industry for tracking tools, materials, and ensuring safety. Researchers in the construction domain have investigated similar uses for UWB-based RTLSs on construction jobsites. However, most of these investigations comprised small-scale experiments using average accuracy only to demonstrate use cases for the technology. Furthermore, they did not consider alternative deployment scenarios for practically feasible deployment of the technology. To overcome these limitations, a series of experiments were performed to study the feasibility of a commercially available RTLS on the construction jobsites. The focus of the work was on feasibility in terms of accuracy analysis of the system for a large experimental site, the level of effort requirements for deployment, and the impact of deployment alternatives on the accuracy of the system. The results found that average accuracy was found to be a misleading indicator of the perceived system performance (i.e., 95th percentile values were considerably higher than average values). Moreover, accuracy is significantly affected by the deployment alternatives. Collectively, the results arising from the study could help construction/safety managers in decision making related to the deployment of UWB-based RTLSs for their construction sites.

Synthetic Control of Quantum Interference by Regulating Charge on a Single Atom in Heteroaromatic Molecular Junctions.

A key area of activity in contemporary molecular electronics is the chemical control of conductance of molecular junctions and devices. Here we study and modify a range of pyrrolodipyridines (carbazole-like) molecular wires. We are able to change the electrical conductance and quantum interference patterns by chemically regulating the bridging nitrogen atom in the tricyclic ring system. A series of eight different N-substituted pyrrolodipyridines has been synthesized and subjected to single-molecule electrical characterization using an STM break junction. Correlations of these experimental data with theoretical calculations underline the importance of the pyrrolic nitrogen in facilitating conductance across the molecular bridge and controlling quantum interference. The large chemical modulation for the meta-connected series is not apparent for the para-series, showing the competition between (i) meta-connectivity quantum interference phenomena and (ii) the ability of the pyrrolic nitrogen to facilitate conductance, that can be modulated by chemical substitution.

Study of Angiographic Relationship between Peripheral Arterial Diseases with the Involvement of Specific Coronary Artery Lesion.

The purpose of this study was to investigate magnitude, pattern and involvement of previously unheralded coronary artery disease in patients suffering from clinically significant peripheral artery disease of lower limbs. This cross sectional study was carried out in National Institute of Cardiovascular Diseases, Dhaka, Bangladesh from January 2014 to February 2015. Total 58 patients with clinically diagnosed peripheral arterial disease of lower limb undergoing angiographic evaluation. Selective CAG in addition to peripheral arteriography was performed in all the study population as per ACC/AHA guidelines for CAG (class IIa recommendation).In this study, it was documented that the proportion of coronary arterial disease was highest in LAD (63.9%) followed by LCX (55.6%), RCA (52.8%), and lowest LM (11.1%) in lesion with aorto-iliac segment. But the proportion of coronary arterial disease was highest in LCX (41.9%) followed by LAD (38.7%), RCA (35.5%), and lowest LM (12.9%) in lesion with femero-popliteal blood vessels. Similarly, the proportion of coronary arterial disease was highest in LCX (36.4%) followed by RCA (27.3%) and equal percentage in LAD and lowest in LM (9.1%) in tibioperoneal segment. Patients of peripheral arterial disease (PAD) having no symptoms of coronary artery disease (CAD) are more likely to have severe coronary artery involvement. Coronary angiogram should be done in patient with PAD to detect previously undetected CAD and pattern of PAD reflects the severity and involvement of coronary arteries.

Oscillating Seebeck coefficients in π-stacked molecular junctions.

When a linear aromatic molecule within a nanogap is bound only to a source electrode, and an adjacent molecule is bound only to a drain electrode, the two molecules can interact via pi-pi stacking, which allows electrons to flow from the source to the drain, via pi-pi bonds. Here we investigate the thermoelectric properties of such junctions, using mono-thiol oligo-phenylene ethynylene (OPE3)-based molecules as a model system. For molecules which are para-connected to the electrodes, we show that the Seebeck coefficient is an oscillatory function of the length L of the pi-pi overlap region and exhibits large positive and negative values. This bi-thermoelectric behavior is a result of quantum interference within the junction, which behaves like a molecular-scale Mach-Zehnder interferometer. For junctions formed from molecular monolayers sandwiched between planar electrodes, this allows both hole-like and electron-like Seebeck coefficients to be realized, by careful control of electrode separation On the other hand for meta-connected molecules, the Seebeck coefficient is insensitive to L, which may be helpful in designing resilient junctions with more stable and predictable thermoelectric properties.

Side-Group-Mediated Mechanical Conductance Switching in Molecular Junctions.

A key target in molecular electronics has been molecules having switchable electrical properties. Switching between two electrical states has been demonstrated using such stimuli as light, electrochemical voltage, complexation and mechanical modulation. A classic example of the latter is the switching of 4,4'-bipyridine, leading to conductance modulation of around 1 order of magnitude. Here, we describe the use of side-group chemistry to control the properties of a single-molecule electromechanical switch, which can be cycled between two conductance states by repeated compression and elongation. While bulky alkyl substituents inhibit the switching behavior, π-conjugated side-groups reinstate it. DFT calculations show that weak interactions between aryl moieties and the metallic electrodes are responsible for the observed phenomenon. This represents a significant expansion of the single-molecule electronics "tool-box" for the design of junctions with electromechanical properties.

Revisiting Hemicraniectomy: Late Decompressive Hemicraniectomy for Malignant Middle Cerebral Artery Stroke and the Role of Infarct Growth Rate.

Objective and Methods. The outcome in late decompressive hemicraniectomy in malignant middle cerebral artery stroke and the optimal timings of surgery has not been addressed by the randomized trials and pooled analysis. Retrospective, multicenter, cross-sectional study to measure outcome following DHC under 48 or over 48 hours using the modified Rankin scale [mRS] and dichotomized as favorable ≤4 or unfavorable >4 at three months. Results. In total, 137 patients underwent DHC. Functional outcome analyzed as mRS 0-4 versus mRS 5-6 showed no difference in this split between early and late operated on patients [P = 0.140] and mortality [P = 0.975]. Multivariate analysis showed that age ≥ 55 years, MCA with additional infarction, septum pellucidum deviation ≥1 cm, and uncal herniation were independent predictors of poor functional outcome at three months. In the "best" multivariate model, second infarct growth rate [IGR2] >7.5 ml/hr, MCA with additional infarction, and patients with temporal lobe involvement were independently associated with surgery under 48 hours. Both first infarct growth rate [IGR1] and second infarct growth rate [IGR2] were nearly double [P < 0.001] in patients with early surgery [under 48 hours]. Conclusions. The outcome and mortality in malignant middle cerebral artery stroke patients operated on over 48 hours of stroke onset were comparable to those of patients operated on less than 48 hours after stroke onset. Our data identifies IGR, temporal lobe involvement, and middle cerebral artery with additional infarct as independent predictors for early surgery.

Solidification of cinnarizine self-nanoemulsifying drug delivery systems by fluid bed coating: optimization of the process and formulation variables.

Self-nanoemulsifying drug delivery systems (SNEDDS) offer an efficient choice to improve the poor dissolution and erratic bioavailability of poorly-water soluble drugs. However, liquid SNEDDS experience some manufacturing and stability limitations. To overcome these limitations, the current study aims to investigate and optimize the solidification of cinnarizine (CN) liquid SNEDDS onto pellets by fluid bed coating. The study involved optimization of process and formulation variables. The coated self-nanoemulsifying pellets (SNEP) were characterized, their droplet size and dissolution profiles were compared to the corresponding liquid SNEDDS. Higher spray/microclimate air pressure led to minimal agglomeration and minimal spray drying. However, slight increase in inlet air volume above 35 m3/h led to extensive spray drying. The optimized coating formula included oleic acid/Imwitor308/Cremophor El (25/25/50) as liquid SNEDDS, HPMC E3 as coating polymer and Plasacryl™T20 as anti-tacking agent. The optimum concentration of coating solution was 15% and optimum SNEDDS proportion in the coating layer was 40%. The droplet size of reconstituted SNEP was significantly (p < 0.05) higher than liquid SNEDDS, yet the SNEP aqueous dispersion was still within the nano-metric scale. Pure CN showed sharp precipitation upon shifting the media from pH 1.2 to 6.8. In contrast, Both SNEP and liquid SNEDDS maintained >85% CN in solution, even at pH 6.8. Therefore, CN-SNEP seems to be an excellent dosage form that maintains the solubilization benefits of liquid SNEDDS, overcomes their limitations along with the additional benefits of solid dosage form.

Ablation of a resistant right atrial appendage tachycardia using a magnetic navigation system.

The right atrial appendage is an uncommon site of origin for ectopic atrial tachycardia. Right atrial appendage tachycardia (RAAT) has been noted to be prevalent in young males and responds well to radiofrequency ablation. We report a case of RAAT resistant to multiple attempts of ablation that responded to ablation using Stereotaxis Niobe™ Magnetic Navigation System (RMN, Stereotaxis, St. Louis, MO, USA).

Symptomatic and asymptomatic carotid artery plaque.

Carotid atherosclerotic plaques represent both stable and unstable atheromatous lesions. Atherosclerotic plaques that are prone to rupture owing to their intrinsic composition such as a large lipid core, thin fibrous cap and intraplaque hemorrhage are associated with subsequent thromboembolic ischemic events. At least 15-20% of all ischemic strokes are attributable to carotid artery atherosclerosis. Characterization of plaques may enhance the understanding of natural history and ultimately the treatment of atherosclerotic disease. MRI of carotid plaque and embolic signals during transcranial Doppler have identified features beyond luminal stenosis that are predictive of future transient ischemic attacks and stroke. The value of specific therapies to prevent stroke in symptomatic and asymptomatic patients with severe carotid artery stenosis are the subject of current research and analysis of recently published clinical trials that are discussed in this article.

Characteristics of Mohs practices in the United States: a recall survey of ACMS surgeons.

OBJECTIVE: The purpose of this study is to better characterize the typical Mohs practice in the United States and to generate data that may be useful in future practice models. METHODS: A survey was mailed in 2004 to all 599 members of the American College of Mohs Surgery with United States addresses listed in the 2003 directory. RESULTS: Most respondents were part of a single speciality group, in a suburban or urban setting, performed between 501-1,000 cases per year, and had been in practice from 0-5 years. The vast majority of Mohs excisions are for basal cell cancers and squamous cell cancers, followed by melanoma. Primary closure is the most common method of repair, followed by the use of flaps. Only 6% of cases were referred to other specialties for closure. Many surgeons augment their practice with non-Mohs cosmetic procedures. CONCLUSION: The characteristics of current Mohs surgery practices in the United States provides useful data for training programs, potential trainees, workforce issues, statistical modeling systems, and Mohs surgeons in the evaluation of their own practices.

Multicentric reticulohistiocytosis.

Multicentric reticulohistiocytosis is a rare granulomatous disease of unknown etiology, characterized by cutaneous nodules and destructive arthritis. Skin lesions can cause significant deformity, and approximately half of affected patients develop a severe disabling arthritis. The disease is often associated with malignancy; however, the paraneoplastic nature of multicentric reticulohistiocytosis is not established. The diagnosis is confirmed by the presence of oncocytic ("ground-glass") histiocytes and multinucleated giant cells on histopathology of the cutaneous nodules and the synovial membrane.

Proliferating multicentric reticulohistiocytosis associated with papillary serous carcinoma of the endometrium.

Multicentric reticulohistiocytosis (MRH) is a rare histocytic disease characterized by destructive arthritis in association with classic skin findings. Although MRH is not strictly a paraneoplastic disease, one quarter of cases are malignancy related. We report a case of MRH with an initial remission followed by an acute exacerbation several years later heralding the clinical presentation of endometrial carcinoma. During this flareup a skin biopsy specimen revealed a diffuse dermal infiltrate composed of histiocytes with ground-glass cytoplasm and multiple atypical mitoses. Approximately 40% of the cells stained with the proliferation marker Ki-67. Treatment of endometrial carcinoma resulted in improvement of skin and joint symptoms, and a repeat biopsy specimen no longer demonstrated mitotic figures. These findings support a reactive and proliferative cause of MRH.