Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) profoundly impacts hemostasis and microvasculature. In the light of the dilemma between thromboembolic and hemorrhagic complications, in ...the present paper, we systematically investigate the prevalence, mortality, radiological subtypes, and clinical characteristics of intracranial hemorrhage (ICH) in coronavirus disease (COVID-19) patients.
Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we performed a systematic review of the literature by screening the PubMed database and included patients diagnosed with COVID-19 and concomitant ICH. We performed a pooled analysis, including a prospectively collected cohort of critically ill COVID-19 patients with ICH, as part of the PANDEMIC registry (Pooled Analysis of Neurologic Disorders Manifesting in Intensive Care of COVID-19).
Our literature review revealed a total of 217 citations. After the selection process, 79 studies and a total of 477 patients were included. The median age was 58.8 years. A total of 23.3% of patients experienced the critical stage of COVID-19, 62.7% of patients were on anticoagulation and 27.5% of the patients received ECMO. The prevalence of ICH was at 0.85% and the mortality at 52.18%, respectively.
ICH in COVID-19 patients is rare, but it has a very poor prognosis. Different subtypes of ICH seen in COVID-19, support the assumption of heterogeneous and multifaceted pathomechanisms contributing to ICH in COVID-19. Further clinical and pathophysiological investigations are warranted to resolve the conflict between thromboembolic and hemorrhagic complications in the future.
The general term of CAD/CAM technology (i.e., Computer-Aided Design/Compute-Aided Manufacturing) comprises several aspects, such as subtractive manufacturing processes, like milling (soft and hard ...milling), and additive manufacturing processes, like Selective Laser Melting (SLM), which refers to metallic materials, or Selective Laser Sintering (SLS), which refers to glasses/glass-ceramics/ceramic, or polymeric, or related composite materials produced via powder metallurgy technique. In biomaterials fabrications, the first step in SLM or SLS technology is the digital design of the prosthetic restoration, whereby the patient's individual anatomical and morphological features are precisely described. Afterwards laser-aided melting or sintering is repeated (layer-by-layer) until the complete restoration item is fabricated. A wide range of dental materials can be produced by SLM or SLS technology, e.g., metals and alloys, thermoplastic polymers, glasses/ceramics, waxes, and thermoplastic composites. Thus, it is a promising technology for producing a variety of dental restorations, such as metal-ceramic restorations, all-ceramic restorations, maxillofacial prostheses, functional skeletons, individual scaffolds for tissue engineering, etc. SLM technology is already widely applied for fabricating metal objects for dental (e.g., Co-Cr alloy) and orthopedic prostheses. As a subsequence, in the last decade, researchers' interest has been shifted to SLS of ceramic powders, such as SiO2, Al2O3, SiO2/Al2O3, and ZrO2/Y2O3. This article comprehensively reviews the SLS process and its prospects for producing glasses/glass-ceramic/ceramic materials for biomedical/dental applications. The experimental results clearly show that this very modern additive manufacturing technology does not jeopardize the properties of the ceramic biomaterials' properties.
This paper reports on synthesis and characterization (sintering, crystallization, microstructure and mechanical properties) of novel alumina-containing (1 mol%) bioactive glass-ceramics (GCs) in ...CaO-MgO-SiO2 system with additives of K2O, Na2O, P2O5, CaF2, and Al2O3. Dense and well-sintered GCs were produced by glass-melt quenching and glass-powder compact sintering. The K-free GCs were comprised of diopside, wollastonite, and fluorapatite, and the K-containing ones consisted of diopside, fluorapatite, and alpha-potassium magnesium silicate (α-PMS). The mechanical properties of the produced GCs were better than those of the titanium and zirconia dental implant materials, and their modulus of elasticity (27–34 GPa), microhardness (6.0–6.7 GPa), and fracture toughness (2.1–2.6 MPa m0.5) are a good match to those of human jaw bone and dentine. The produced GCs were also bioactive, which was witnessed by the formation of hydroxyapatite on their surface after their immersion in simulated body fluid at 37 °C.
Despite increasing recognition that mentoring is essential early in medical careers, little is known about the prevalence of mentoring programs for medical students. We conducted this study to survey ...all medical schools in Germany regarding the prevalence of mentoring programs for medical students as well as the characteristics, goals and effectiveness of these programs.
A definition of mentoring was established and program inclusion criteria were determined based on a review of the literature. The literature defined mentoring as a steady, long-lasting relationship designed to promote the mentee's overall development. We developed a questionnaire to assess key characteristics of mentoring programs: the advocated mentoring model, the number of participating mentees and mentors, funding and staff, and characteristics of mentees and mentors (e.g., level of training). In addition, the survey characterized the mentee-mentor relationship regarding the frequency of meetings, forms of communication, incentives for mentors, the mode of matching mentors and mentees, and results of program evaluations. Furthermore, participants were asked to characterize the aims of their programs. The questionnaire consisted of 34 questions total, in multiple-choice (17), numeric (7) and free-text (10) format. This questionnaire was sent to deans and medical education faculty in Germany between June and September 2009. For numeric answers, mean, median, and standard deviation were determined. For free-text items, responses were coded into categories using qualitative free text analysis.
We received responses from all 36 medical schools in Germany. We found that 20 out of 36 medical schools in Germany offer 22 active mentoring programs with a median of 125 and a total of 5,843 medical students (6.9 - 7.4% of all German medical students) enrolled as mentees at the time of the survey. 14 out of 22 programs (63%) have been established within the last 2 years. Six programs (27%) offer mentoring in a one-on-one setting. 18 programs (82%) feature faculty physicians as mentors. Nine programs (41%) involve students as mentors in a peer-mentoring setting. The most commonly reported goals of the mentoring programs include: establishing the mentee's professional network (13 programs, 59%), enhancement of academic performance (11 programs, 50%) and counseling students in difficulties (10 programs, 45%).
Despite a clear upsurge of mentoring programs for German medical students over recent years, the overall availability of mentoring is still limited. The mentoring models and goals of the existing programs vary considerably. Outcome data from controlled studies are needed to compare the efficiency and effectiveness of different forms of mentoring for medical students.
The Save ChildS Study demonstrated that endovascular thrombectomy (EVT) is a safe treatment option for pediatric stroke patients with large vessel occlusions (LVOs) with high recanalization rates. ...Our aim was to determine the long-term cost, health consequences and cost-effectiveness of EVT in this patient population.
In this retrospective study, a decision-analytic Markov model estimated lifetime costs and quality-adjusted life years (QALYs). Early outcome parameters were based on the entire Save ChildS Study to model the EVT group. As no randomized data exist, the Save ChildS patient subgroup with unsuccessful recanalization was used to model the standard of care group. For modeling of lifetime estimates, pediatric and adult input parameters were obtained from the current literature. The analysis was conducted in a United States setting applying healthcare and societal perspectives. Probabilistic sensitivity analyses were performed. The willingness-to-pay threshold was set to $100,000 per QALY.
The model.
yielded EVT as the dominant (cost-effective as well as cost-saving) strategy for pediatric stroke patients. The incremental effectiveness for the average age of 11.3 years at first stroke in the Save ChildS Study was determined as an additional 4.02 lifetime QALYs, with lifetime cost-savings that amounted to $169,982 from a healthcare perspective and $254,110 when applying a societal perspective. Acceptability rates for EVT were 96.60% and 96.66% for the healthcare and societal perspectives.
EVT for pediatric stroke patients with LVOs resulted in added QALY and reduced lifetime costs. Based on the available data in the Save ChildS Study, EVT is very likely to be a cost-effective treatment strategy for childhood stroke.
Among different silicate systems, CaO−MgO−SiO2 is the one of the most promising due to abundance of reagents, easier fabrication, improved performance, and wide range of application. Analysis of the ...current literature sources denotes that phase diagram of CaO−MgO−SiO2 system is regularly used by researchers worldwide as constitutive model for synthesis glass-ceramic materials (GCs) possessing an adequate combination of high chemical durability, mechanical and electrical properties. In recent years, materials from this system attracted extra interest for applications in bone tissue repair owing to their ability to induce hydroxyapatite formation in contact with body fluids and to be resorbed in controllable degradation rate.
In this brief review diopside containing compositions are specifically discussed. The main goal is to provide critical analysis of the experimental trials directed on synthesis of GC materials in the CaO−MgO−SiO2 system. Glass compositions were analysed through the standpoint of their location in the relevant region, or phase field, within a phase diagram to guide GC production and to make educated choices of compositions and processing parameters.
Apart from Introduction and Conclusions this review comprises five consecutive parts. In the first part, constitution of phase diagram of CaO−MgO−SiO2 system is comprehensively discussed with connection to melts’ crystallization path and crystalline phase formation. In the second part, special attentiveness is drawn towards diopside- containing GCs produced from wastes and non-expensive natural raw materials. In this regard and taking into consideration presence of Al2O3 in the majority types of wastes, cross sections of CaO−MgO−SiO2−Al2O3 system with 10, 15 and 20% of Al2O3 are suggested to utilize when anticipating ultimate crystalline phase(s) formation. The following parts of this review are mostly addressed to recent advancement in producing optimized diopside-containing glass–ceramic biomaterials for bone repair as well as innovative sealants for solid oxide fuel cells (SOFC). Likewise, some other active areas of research and application for diopside containing GC compositions are briefly discussed.
Background: Neurologic symptom severity and deterioration at 24 hours (h) predict long-term outcomes in patients with acute large vessel occlusion (LVO) stroke of the anterior circulation. We aimed ...to examine the association of baseline multiparametric CT imaging and clinical factors with the course of neurologic symptom severity in the first 24 h after endovascular treatment (EVT). Methods: Patients with LVO stroke of the anterior circulation were selected from a prospectively acquired consecutive cohort of patients who underwent multiparametric CT, including non-contrast CT, CT angiography and CT perfusion before EVT. The symptom severity was assessed on admission and after 24 h using the 42-point National Institutes of Health Stroke Scale (NIHSS). Clinical and imaging data were compared between patients with and without early neurological deterioration (END). END was defined as an increase in ≥4 points, and a significant clinical improvement as a decrease in ≥4 points, compared to NIHSS on admission. Multivariate regression analyses were used to determine independent associations of imaging and clinical parameters with NIHSS score increase or decrease in the first 24 h. Results: A total of 211 patients were included, of whom 38 (18.0%) had an END. END was significantly associated with occlusion of the internal carotid artery (odds ratio (OR), 4.25; 95% CI, 1.90–9.47) and the carotid T (OR, 6.34; 95% CI, 2.56–15.71), clot burden score (OR, 0.79; 95% CI, 0.68–0.92) and total ischemic volume (OR, 1.01; 95% CI, 1.00–1.01). In a comprehensive multivariate analysis model including periprocedural parameters and complications after EVT, carotid T occlusion remained independently associated with END, next to reperfusion status and intracranial hemorrhage. Favorable reperfusion status and small ischemic core volume were associated with clinical improvement after 24 h. Conclusions: The use of imaging parameters as a surrogate for early NIHSS progression in an acute LVO stroke after EVT reached limited performance with only carotid T occlusion as an independent predictor of END. Reperfusion status and early complications in terms of intracranial hemorrhage are critical factors that influence patient outcome in the acute stroke phase after EVT.
The present in vitro study aims at characterizing dental zirconia ceramics, which are stabilized with a high amount of Y2O3. Two groups of specimens were fabricated by computer‐aided ...design/computer‐aided manufacturing technique. The specimens of each group were divided into two subgroups (SGs): SGs 1a and 2a contained a relatively low amount of Y2O3 (6–8 wt.%), whereas SGs 1b and 2b contained a higher amount of Y2O3 (8–10 wt.%). The influence of yttria content on their microstructure and mechanical properties was experimentally determined. The statistical significance of the differences in the mechanical properties between the SGs was evaluated by the t‐test (p < 5% was considered statistically significant). Homogeneous and dense ceramics with fine nanostructure, comprising grains of yttria‐stabilized tetragonal and cubic zirconia, sized between ∼160 and ∼800 nm, were produced. The increase of yttria content, which causes an increase in grain size, favors the formation of cubic zirconia, resulting in mechanical properties’ slight reduction; yet, the differences were not statistically significant. Consequently, the mechanical properties (HV 11.74–12.91 GPa, and KIC 2.66–4.25 MPa m0.5) and the good esthetics of the investigated zirconia ceramics stabilized with high yttria content qualify these zirconia materials for fabricating dental restorations, because they can approach the properties and the esthetics of dental hard tissues as well as the tooth structure.
The aim of the present work was to evaluate six commercially available abutment screws by characterising roughness parameters, microstructure and mechanical properties.
Six abutment screws from each ...implant system, were used. The surface roughness parameters (Sa, Sq, Ssk, Sku, Spk, Sk and Svk) were identified by an optical interferometric profiler. Microstructural observations and crystallographic analysis were performed using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectroscopy (EDX) device for elemental analysis and an X-ray diffractometer (XRD), respectively. The Martens Hardness (HM), Indentation Modulus (EIT), elastic index (ηIT) and Vickers hardness (HV) of all specimens were determined by instrumented indentation testing (IIT). The results were analyzed by one-way ANOVA and Tukey multiple-comparison tests (a=0.05).
EDX and XRD showed the abutment screws to be mixed α- and β-phase titanium alloys. Microstructural analysis revealed a fine homogeneous microstructure without porosity, consisting of fine dispersoid rods of β-phase embedded in a continuous α-phase matrix. Statistically significant differences were found among the mechanical properies and surface roughness parameters apart from Sq, Spk and Svk.
The tested abutment screws showed significant differences in the probed properties, and, thus, differences in their clinical behaviour are anticipated.
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