Development of Nanocomposite Powders for the SLS Process to Enhance Mechanical Properties

In an effort to fabricate prototypes with improved mechanical properties in the dual laser sintering process, functionalized graphite nanoplatelets were added to the PA-12 powder to produce a nanocomposite powder. The PA-12 powder was chosen as the matrix polymer because it has features conducive to laser sintering such as relatively low melting temperature and high mechanical properties. The GNPs were oxidized through a nitric acid treatment to improve the interfacial bonding. The resulting nanocomposite powder was layered and sintered by laser without any sign of agglomeration. Although the result is preliminary, it nevertheless shows the suitability of the nanocomposite powder for the laser sintering process.Mechanical Engineerin

Comparison of volume-controlled and pressure-controlled ventilation using a laryngeal mask airway during gynecological laparoscopy

Background: Several publications have reported the successful, safe use of Laryngeal Mask Airway (LMA)-Classic devices in patients undergoing laparoscopic surgery. However, there have been no studies that have examined the application of volume-controlled ventilation (VCV) or pressure-controlled ventilation (PCV) using a LMA during gynecological laparoscopy. The aim of this study is to compare how the VCV and PCV modes and using a LMA affect the pulmonary mechanics, the gas exchange and the cardiovascular responses in patients who are undergoing gynecological laparoscopy. Methods: Sixty female patients were randomly allocated to one of two groups, (the VCV or PCV groups). In the VCV group, baseline ventilation of the lung was performed with volume-controlled ventilation and a tidal volume of 10 ml/kg ideal body weight (IBW). In the PCV group, baseline ventilation of the lung using pressure-controlled ventilation was initiated with a peak airway pressure that provided a tidal volume of 10 ml/kg IBW and an upper limit of 35 cmH2O. The end-tidal CO2, the peak airway pressures (Ppeak), the compliance, the airway resistance and the arterial oxygen saturation were recorded at T1: 5 minutes after insertion of the laryngeal airway, and at T2 and T3: 5 and 15 minutes, respectively, after CO2 insufflation. Results: The Ppeak at 5 minutes and 15 minutes after CO2 insufflation were significantly increased compared to the baseline values in both groups. Also, at 5 minutes and 15 minutes after CO2 insufflation, there were significant differences of the Ppeak between the two groups. The compliance decreased in both groups after creating the pneumopertoneim (P < 0.05). Conclusions: Our results demonstrate that PCV may be an effective method of ventilation during gynecological laparoscopy, and it ensures oxygenation while minimizing the increases of the peak airway pressure after CO2 insufflation. ��� the Korean Society of Anesthesiologists, 2011

Alpha-tocopherol exerts protective function against the mucotoxicity of particulate matter in amphibian and human goblet cells

Exposure to particulate matter (PM) in ambient air is known to increase the risk of cardiovascular disorders and mortality. The cytotoxicity of PM is mainly due to the abnormal increase of reactive oxygen species (ROS), which damage cellular components such as DNA, RNA, and proteins. The correlation between PM exposure and human disorders, including mortality, is based on long-term exposure. In this study we have investigated acute responses of mucus-secreting goblet cells upon exposure to PM derived from a heavy diesel engine. To this end, we employed the mucociliary epithelium of amphibian embryos and human Calu-3 cells to examine PM mucotoxicity. Our data suggest that acute exposure to PM significantly impairs mucus secretion and results in the accumulation of mucus vesicles in the cytoplasm of goblet cells. RNA-seq analysis revealed that acute responses to PM exposure significantly altered gene expression patterns; however, known regulators of mucus production and the secretory pathway were not significantly altered. Interestingly, pretreatment with alpha-tocopherol nearly recovered the hyposecretion of mucus from both amphibian and human goblet cells. We believe this study demonstrates the mucotoxicity of PM and the protective function of alpha-tocopherol on mucotoxicity caused by acute PM exposure from heavy diesel engines

Endovascular Therapy for Acute Ischemic Stroke of Intracranial Atherosclerotic Origin—Neuroimaging Perspectives

Large vessel occlusion (LVO) due to intracranial atherosclerosis (ICAS) is a common cause of acute ischemic stroke (AIS) in Asians. Endovascular therapy (EVT) has been established as the mainstay of treatment in patients with AIS and LVO. However, only a few patients of Asian descent with ICAS-related LVO (ICAS-LVO) were included in recent randomized controlled trials of EVT for AIS. Therefore, the findings of these trials cannot be directly applied to Asian patients with ICAS-LVO. In embolic LVO due to thrombus from the heart or a more proximal vessel, rapid, and complete recanalization can be achieved in more than 70–80% of patients, and it is important to exclude patients with large cores. In contrast, patients with ICAS-LVO usually have favorable hemodynamic profiles (good collateral status, small core, and less severe perfusion deficit), but poor response to EVT (more rescue treatments and longer procedure times are required for successful recanalization due to higher rates of reocclusion). Patients with ICAS-LVO may have different anatomic (plaque, angioarchitecture), hemodynamic (collateral status), and pathophysiologic (thrombus composition) features on neuroimaging compared to patients with embolic LVO. In this review, we discuss these neuroimaging features, their clinical implications with respect to determination of EVT responses, and the need for development of specific EVT devices and procedures for patients with ICAS-LVO

Implementation of central line-associated bloodstream infection prevention bundles in a surgical intensive care unit using peer tutoring

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Abstract Background Central line-associated bloodstream infections (CLABSIs) can be prevented through well-coordinated, multifaceted programs. However, implementation of CLABSI prevention programs requires individualized strategies for different institutional situations, and the best strategy in resource-limited settings is uncertain. Peer tutoring may be an efficient and effective method that is applicable in such settings. Methods A prospective intervention was performed to reduce CLABSIs in a surgical intensive care unit (SICU) at a tertiary hospital. The core interventions consisted of implementation of insertion and maintenance bundles for CLABSI prevention. The overall interventions were guided and coordinated by active educational programs using peer tutoring. The CLABSI rates were compared for 9 months pre-intervention, 6 months during the intervention and 9 months post-intervention. The CLABSI rate was further observed for three years after the intervention. Results The rate of CLABSIs per 1000 catheter-days decreased from 6.9 infections in the pre-intervention period to 2.4 and 1.8 in the intervention (6 m; P = 0.102) and post-intervention (9 m; P = 0.036) periods, respectively. A regression model showed a significantly decreasing trend in the infection rate from the pre-intervention period (P < 0.001), with incidence-rate ratios of 0.348 (95% confidence interval [CI], 0.98–1.23) in the intervention period and 0.257 (95% CI, 0.07–0.91) in the post-intervention period. However, after the 9-month post-intervention period, the yearly CLABSI rates reverted to 3.0–5.4 infections per 1000 catheter-days over 3 years. Conclusions Implementation of CLABSI prevention bundles using peer tutoring in a resource-limited setting was useful and effectively reduced CLABSIs. However, maintaining the reduced CLABSI rate will require further strategies

Multimodal MRI-Based Triage for Acute Stroke Therapy: Challenges and Progress

Revascularization therapies have been established as the treatment mainstay for acute ischemic stroke. However, a substantial number of patients are either ineligible for revascularization therapy, or the treatment fails or is futile. At present, non-contrast computed tomography is the first-line neuroimaging modality for patients with acute stroke. The use of magnetic resonance imaging (MRI) to predict the response to early revascularization therapy and to identify patients for delayed treatment is desirable. MRI could provide information on stroke pathophysiologies, including the ischemic core, perfusion, collaterals, clot, and blood–brain barrier status. During the past 20 years, there have been significant advances in neuroimaging as well as in revascularization strategies for treating patients with acute ischemic stroke. In this review, we discuss the role of MRI and post-processing, including machine-learning techniques, and recent advances in MRI-based triage for revascularization therapies in acute ischemic stroke

A New Dual Circularly Polarized Feed Employing a Dielectric Cylinder-Loaded Circular Waveguide Open End Fed by Crossed Dipoles

This paper presents a new dual circularly polarized feed that provides good axial ratio over wide angles and low cross-polarized radiation in backward direction. A circular waveguide open end is fed with two orthogonally polarized waves in phase quadrature by a pair of printed crossed dipoles and a compact connectorized quadrature hybrid coupler. The waveguide aperture is loaded with a dielectric cylinder to reduce the cross-polarization beyond 90 degrees off the boresight. The fabricated feed has, at 5.5 GHz, 6.33-dBic copolarized gain, 3-dB beamwidth of 106°, 10-dB beamwidth of 195°, 3-dB axial ratio beamwidth of 215°, maximum cross-polarized gain of −21.4 dBic, and 27-dB port isolation. The reflection coefficient of the feed is less than −10 dB at 4.99–6.09 GHz

Effect of Diabetes Mellitus on Symptomatic Improvement After Surgery for Benign Prostatic Hyperplasia in Patients With Lower Urinary Tract Symptom and its Relations With Prostatic Urethral Angulation

Purpose To compare improvement of lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia in diabetic versus nondiabetic patients after transurethral resection of the prostate (TURP) or holmium laser enucleation of the prostate (HoLEP). Methods The medical records of 437 patients who underwent TURP or HoLEP at a tertiary referral center from January 2006 to January 2022 were retrospectively analyzed. Among them, 71 patients had type 2 diabetes. Patients in the diabetic mellitus (DM) and non-DM groups were matched 1:1 according to age, baseline International Prostate Symptom Score (IPSS), and ultrasound measured prostate volume. Changes in LUTS were assessed at 3 months after surgery using IPSS and evaluated by categorizing patients according to prostatic urethral angulation (PUA; <50° vs. ≥50°). Medication-free survival after surgery was also investigated. Results No significant differences were noted between the DM and non-DM groups in baseline characteristics except for comorbidities (i.e., hypertension, cerebrovascular disease, and ischemic heart disease, P=0.021, P=0.002, and P=0.017, respectively) and postvoid residual urine volume (115±98 mL vs. 76±105 mL, P=0.028). Non-DM patients showed significant symptomatic improvement regardless of PUA, while DM patients demonstrated improvement in obstructive symptoms only in those with large PUA (≥51°). Among patients with small PUA, DM patients had worse medication-free survival after surgery compared to controls (P=0.044) and DM was an independent predictor of medication reuse (hazard ratio, 1.422; 95% confidence interval, 1.285–2.373; P=0.038). Conclusions DM patients experienced symptomatic improvement after surgery only in those with large PUA. Among patients with small PUA, DM patients were more likely to reuse medication after surgery