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We realized a simple approach involving the 1,6‐conjugate addition (regioselective thiolation) of para‐quinone methides (p‐QMs) with easily available thio‐based nucleophiles. Through ring‐closing metathesis (RCM), this procedure delivered a variety of para‐ and meta‐thiaoxacyclophanes as E‐isomers in good yields. A simple thiol‐free one‐pot approach is reported for the direct synthesis of sulfides and sulfones under green reaction conditions without the use of any metal catalysts. Low‐cost and easily accessible compounds such as p‐QMs and benzyl bromides are used as starting materials in the presence of potassium thioacetate (PTA) and Oxone®. Novel thiaoxacyclophanes were assembled in three simple steps including conjugate addition of PTA, Grignard addition, and RCM sequence. [ABSTRACT FROM AUTHOR]

A stereoselective [3+2] cycloaddition approach to functionalized pentaquinanes starting from cis‐syn‐cis triquinanes, derived from Cookson's diones, is reported. This transformation involves generation of six new stereocenters in a single step leading to cis‐anti‐cis‐syn‐cis‐anti‐cis polyquinane systems. Our method prevents transannular cyclizations which are prevalent in these moieties. The structure and stereochemistry of target molecules are well‐characterized based on NMR data and X‐ray diffraction studies. [ABSTRACT FROM AUTHOR]

We report an efficient synthetic strategy to diverse hydantoins and thiohydantoins involving a three‐component reaction with the aid of deep eutectic solvent. Here, N,N′‐dimethyl urea and N,N′‐dimethyl thiourea play a dual role as reactant and reaction medium along with l‐(+)‐tartaric acid. The three‐component reaction provides an easy access to 5‐amino‐1,3‐dialkyl‐substituted hydantoins and thiohydantoins in good yields. [ABSTRACT FROM AUTHOR]

This paper investigates a two-part architecture for a Knudsen vacuum pump with no moving parts. This type of pump exploits the thermal transpiration that results from the free-molecular flow in nonisothermal channels. For a high compression ratio, 162 stages are serially cascaded. The two-part architecture uses 54 stages designed for the pressure range from 760 to ≈ 50 Torr, and 108 stages designed for lower pressures. This approach provides greater compression ratio and speed than using a uniform design for each stage. Finite element simulations and analytical design analysis are presented. A five-mask single-wafer fabrication process is used for monolithic integration of the Knudsen pump that has a footprint of 12 × 15 mm2. The pressure levels of each stage are measured by integrated Pirani gauges. Experimental evaluation shows that, using an input power of ≈ 0.39 W, the evacuated chamber is reduced from 760 to ≈ 0.9 Torr, resulting in a compression ratio of ≈ 844. The vacuum levels are sustained during 37 days of continuous operation. [ABSTRACT FROM AUTHOR]

This paper describes the use of low-temperature atomic layer deposition (ALD) of Al2O3, for vacuum seals in wafer-level vacuum packaging and other applications. The conformal coverage provided by ALD Al2O3 is shown to seal circular micromachined cavities. The cavities are 0.8 lm in height, 400 lm in diameter, and are capped by porous plasma-enhanced chemical vapor deposited dielectrics that form a membrane. The ALD Al2O3 film, of thickness ≈0.2 lm, is deposited at a temperature of 250 °C on this membrane. The retention of vacuum is indicated by the deflection of the membrane. Lifetime tests extending out to 19 months are reported. [ABSTRACT FROM AUTHOR]

Introduction: Irrigating solutions are used for cleaning and removing dentinal debris, and the other remains from pulpal space during biomechanical preparation. Therefore, we evaluated the impact of various irrigating agents on root fracture at 5-minute time exposure., Materials and Methods: We sectioned 60 permanent maxillary premolars with fully formed root structures transversely maintaining the root length of approximately 14 mm. Five study groups were made comprising ethylenediaminetetraacetic acid (EDTA), cetrimide, citric acid, and so on as various irrigating agents. A universal force test machine was used to calculate the force which was enough to fracture each root. Analysis of variance (ANOVA) test was used to access the level of significance., Results: About 10% citric acid solution as an irrigating agent showed minimal fracture opposing results, whereas 10% EDTA solution showed the maximum fracture resistance of root portion., Clinical Significance: Selection of suitable EDTA concentration that has minimal adverse effect on the mechanical properties of the tooth is very important for the successful management of tooth fracture., Conclusion: About 10% EDTA provided the highest fracture resistance, necessitating the use of irrigating solution in root canal therapy (RCT). Further research with higher and different study groups is required to search for more efficient irrigating solution to improve the outcome of RCT.

Diagnosis of acute myocardial infarction (AMI) has to be made early in the emergency triage since maximal mortality occurs within first hour and the benefits of all interventions are greater once these are instituted early. Diagnosis is easy and based on simple principals of good history, physical examination, early and complete 12 lead electrocardiogram and use of echocardiography which should be available in the emergency triage area. Subsequently biomarkers are also available for documentation and risk stratification. The other causes of acute severe chest pain should be kept in mind and ruled out. The role of myocardial perfusion imaging for diagnosis of AMI is limited. The diagnosis also involves an estimation of the size of infarct, duration since onset of the process, any acute complications of AMI and the likely vessel involved since these have significant therapeutic implications.

Many cases of progressive heart failure due to cardiac amyloidosis remain undiagnosed due to the rarity and lack of suspicion on part of physician. Treatment options are limited and patients are also poor responders in later stages. Hence, early diagnosis by recognition of syndromic presentation and diagnostic modalities is helpful in retarding the disease process.