Biocorrosion and Cytotoxicity Studies on Biodegradable Mg-Based Multicomponent Alloys.

Magnesium-based multicomponent alloys with different compositions, namely Mg60Al20Zn5Cu10Mn5 (Mg60 alloy), Mg70Al15Zn5Cu5Mn5 (Mg70 alloy), and Mg80Al5Cu5Mn5Zn5 (Mg 80) alloys, were prepared using the disintegrated melt deposition technique. The DMD technique is a distinctive method that merges the benefits from gravity die casting and spray forming. This approach facilitates high solidification rates, process yields, and reduced metal wastage, resulting in materials with a fine microstructure and minimal porosity. Their potential as biodegradable materials was assessed through corrosion in different simulated body fluids (SBFs), microstructure, and cytotoxicity tests. It was observed that the Mg60 alloy exhibited low corrosion rates (~× 10-5 mm/year) in all SBF solutions, with a minor amount of corrosive products, and cracks were observed. This can be attributed to the formation of the Mg32(AlZn)49 phase and to its stability due to Mg(OH)2 film, leading to excellent corrosion resistance when compared to the Mg70 and M80 alloys. Conversely, the Mg80 alloy exhibited high corrosion rates, along with more surface degradation and cracks, due to active intermetallic phases, such as Al6Mn, Al2CuMg, and Al2Cu phases. The order of corrosion resistance for the Mg alloy was found to be ASS > HBSS > ABP > PBS. Further, in vitro cytotoxicity studies were carried out using MDA-MB-231 tumor cells. By comparing all three alloys, in terms of proliferation and vitality, the Mg80 alloy emerged as a promising material for implants, with potential antitumor activity.

Differential expression of PEA3 in odontogenic cysts and tumors.

BACKGROUND: PEA3 transcription factor has been identified as a downstream target of the MAPK and PI3K pathways, and PEA3 overexpression has been observed in a variety of tumor types. We aimed to evaluate PEA3 expression in odontogenic cysts and tumors and compare the expression among odontogenic lesions. In addition, the correlations between PEA3 expression and clinicopathological characteristics of conventional ameloblastoma and unicystic ameloblastoma were investigated. METHODS: This study was performed on 165 samples of odontogenic cysts and tumors including 20 dentigerous cysts, 20 odontogenic keratocysts, 16 adenomatoid odontogenic tumors, 5 ameloblastic fibromas, 45 unicystic ameloblastomas, and 59 conventional ameloblastomas. The sections were immunohistochemically stained with mouse monoclonal anti-PEA3 antibody and PEA3 expression was evaluated as the immunoreactive score. RESULTS: PEA3 expression was absent in all dentigerous cysts (DCs) and odontogenic keratocysts, while all adenomatoid odontogenic tumors showed either no (75%) or low (25%) expression of PEA3. Most of the ameloblastic fibromas (60%) displayed no PEA3 expression. A high expression of PEA3 was observed in a substantial number of unicystic ameloblastomas (48.9%) and conventional ameloblastomas (49.2%) in our study. PEA3 expression in DCs, odontogenic keratocysts and adenomatoid odontogenic tumors were significantly different from that in conventional ameloblastomas and that in unicystic ameloblastomas (p < 0.05). The expression of PEA3 was significantly different in the age groups of unicystic ameloblastomas and histological subtypes of conventional ameloblastomas (p < 0.05). CONCLUSION: PEA3 overexpression is predominant in unicystic ameloblastomas and conventional ameloblastomas compared to other odontogenic lesions, indicating a pivotal role of PEA3 as a downstream effector of MAPK pathway in these two odontogenic lesions.

Measurement properties of all versions of the Stroke Specific Quality of Life Scale (SS-QOL) 2.0: a systematic review protocol.

OBJECTIVE: The aim of this review is to critically appraise and summarize the quality of the measurement properties of all versions of the Stroke Specific Quality of Life Scale (SS-QOL) version 2.0. INTRODUCTION: The Stroke Specific Quality of Life Scale version 2.0 was developed as a comprehensive measure in assessing the quality of life of stroke survivors. The shortened version and cross-culturally translated versions are further developed in different countries. A systematic review will clarify the levels of reliability and validity of all versions. INCLUSION CRITERIA: The population of interest for this review will include adult stroke survivors of either sex diagnosed with a stroke (ischemic or hemorrhagic) who have no other comorbidities affecting their quality of life. The SS-QOL version 2.0 will be the specific instrument of interest, and the quality of life of stroke survivors will be the construct of interest in this review. The measures of reliability, validity, and responsiveness will be assessed as outcomes. Only the studies evaluating the reliability, validity, and responsiveness of all versions of the SS-QOL 2.0 will be included in the review. METHODS: A literature search will be conducted for published studies in MEDLINE and Embase, and unpublished data in Google Scholar and ProQuest Dissertations and Theses. After a three-step search strategy, study selection will be done by two reviewers independently. Then, the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) methodology will be applied for assessment of methodological quality, data extraction, and synthesis. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO CRD42020211727.

Rate and Modifiable Predictors of 30-Day Readmission in Patients with Acute Respiratory Distress Syndrome in the United States.

Background The 30-day readmission rates are being used as a quality measure by Centers for Medicare and Medicaid Services (CMS) for specific medical and surgical conditions. Acute respiratory distress syndrome (ARDS) is one of the important causes of morbidity and mortality in the United States (US). The characteristics and predictors of 30-day readmission in ARDS patients in the US are not widely known, which we have depicted in our study. Objective The aim of this study is to identify 30-day readmission rates, characteristics, and predictors of ARDS patients using the largest publicly available nationwide database. Methods We used the National Readmission Database from the year 2013 to extract the patients with ARDS by primary discharge diagnosis with ICD9-CM codes. All-cause unplanned 30-day readmission rates were calculated for patients admitted between January and November 2013. The independent predictors for unplanned 30-day readmission were identified by survey logistic regression. Results After excluding elective readmission, the all-cause unplanned 30-day readmission rate for ARDS patients was 18%. Index admissions readmitted within 30-day had a significantly higher baseline burden of comorbidities with a Charlson Comorbidity Index (CCI) ≥1 as compared to those who were not readmitted within 30 days. In multivariate regression analysis, several predictors associated with 30-day readmission were self-pay/no charge/other (OR 1.19, 95%CI: 1.02-1.38; p = 0.02), higher-income class (OR 0.86, 95%CI:0.79-0.99; p = 0.03), private insurance (OR 0.81, 95%CI:0.67-0.94; p = 0.01), and teaching metropolitan hospital (OR 0.72, 95%CI:0.61-0.94; p = 0.01). Conclusion The unplanned 30-day readmission rates are higher in ARDS patients in the US. Several modifiable factors such as insurance, socioeconomic status, and hospital type are associated with 30-day readmission among ARDS patients.

Development of Novel Lightweight Metastable Metal-(Metal + Ceramic) Composites Using a New Powder Metallurgy Approach.

In the current study, metal-(metal + ceramic) composites composed of biocompatible elements, magnesium (Mg), zinc (Zn), calcium (Ca) and manganese (Mn) were synthesized using a sinter-less powder metallurgy method. The composite has a composition of Mg49Zn49Ca1Mn1 (wt.%) in which the compositional ratio between Mg and Zn was chosen to be near eutectic Mg-Zn composition. The synthesis method was designed to avoid/minimize intermetallic formation by using processing temperatures lower than the Mg-Zn binary eutectic temperature (~ 340 °C). The synthesis process involved extrusion of green compacts at two different temperatures, 150 °C and 200 °C, without sintering. Extrusion was performed directly on the green compacts as well as on the compacts soaked at temperatures of 150 °C and 200 °C, respectively. Microstructure and mechanical properties of the materials synthesized under various processing conditions were investigated. Effect of extrusion temperature as well as soaking temperature on the materials' properties were also evaluated in details and different properties showed an optimum under different conditions. All the synthesized materials showed no evidence of intermetallic formation which was confirmed by SEM/EDS, XRD, and Differential Scanning Calorimetry (DSC) techniques. The study establishes development of unconventional metal-(metal + ceramic) eco-friendly composites and provides important insight into realizing certain properties without using sintering step thus to minimize the energy consumption of the process. The study also highlights the use of magnesium turnings (recyclability) to develop advanced materials.

Postoperative handover among nurses in an orthopedic surgical setting in Myanmar: a best practice implementation project.

OBJECTIVES: The aim of this project was to improve the postoperative handover practice within the local context of an orthopedic surgical setting by implementing best practice. INTRODUCTION: Clinical handover is a communicative process where the responsibility of patient care is transferred through the exchange of patient information between the care providers. Postoperative handover is an important phase of perioperative care that presents challenges to handover personnel due to transitions in care throughout the perioperative period and the inability of surgical patients to participate in their own care. This paper reports on the best practice implementation project conducted in the field of postoperative handover among nurses in a 500-bed orthopedic surgical setting in Myanmar in 2017. METHODS: The project used the JBI Practical Application of Clinical Evidence System and the Getting Research into Practice audit tool to conduct a baseline audit and two follow-up audits. A total of 120 postoperative handovers were observed and data were collected. Education sessions and a series of discussion and engagement efforts were employed to increase the compliance with evidence-based postoperative handover practice. RESULTS: Baseline audit showed low compliance in audit criteria 3, 5 and 6, whereas varying compliance was observed in criteria 1, 2 and 4. Improvement was seen with five criteria in follow-up audits except for criterion 1. Compliance with criterion 1 was inconclusive because staff attendance at postoperative handovers varied, depending on patients' different handover needs. Nurses attendance, however, improved through engagement efforts and education sessions. CONCLUSION: We were able to make significant improvements in the underperforming areas related to postoperative patient handover. This project confirms that an SBAR (Situation, Background, Assessment, Recommendation) checklist has been implemented to navigate and document every postoperative handover at the main operating theater; the handover process at the intensive care unit complies with the COLD (Connect, Observe, Listen, Delegate) process; and attendance of handovers by nurses has increased. It is recommended that regular audits be conducted to sustain the change and improve where required.

Evolution of Mechanisms that Control Mating in Drosophila Males.

Genetically wired neural mechanisms inhibit mating between species because even naive animals rarely mate with other species. These mechanisms can evolve through changes in expression or function of key genes in sensory pathways or central circuits. Gr32a is a gustatory chemoreceptor that, in D. melanogaster, is essential to inhibit interspecies courtship and sense quinine. Similar to D. melanogaster, we find that D. simulans Gr32a is expressed in foreleg tarsi, sensorimotor appendages that inhibit interspecies courtship, and it is required to sense quinine. Nevertheless, Gr32a is not required to inhibit interspecies mating by D. simulans males. However, and similar to its function in D. melanogaster, Ppk25, a member of the Pickpocket family, promotes conspecific courtship in D. simulans. Together, we have identified distinct evolutionary mechanisms underlying chemosensory control of taste and courtship in closely related Drosophila species.

Tensile and Compressive Responses of Ceramic and Metallic Nanoparticle Reinforced Mg Composites.

In the present study, room temperature mechanical properties of pure magnesium, Mg/ZrO2 and Mg/(ZrO2 + Cu) composites with various compositions are investigated. Results revealed that the use of hybrid (ZrO2 + Cu) reinforcements in Mg led to enhanced mechanical properties when compared to that of single reinforcement (ZrO2). Marginal reduction in mechanical properties of Mg/ZrO2 composites were observed mainly due to clustering of ZrO2 particles in Mg matrix and lack of matrix grain refinement. Addition of hybrid reinforcements led to grain size reduction and uniform distribution of hybrid reinforcements, globally and locally, in the hybrid composites. Macro- and micro- hardness, tensile strengths and compressive strengths were all significantly increased in the hybrid composites. With respect to unreinforced magnesium, failure strain was almost unchanged under tensile loading while it was reduced under compressive loading for both Mg/ZrO2 and Mg/(ZrO2 + Cu) composites.

Synthesis and Characterization of Nano Boron Nitride Reinforced Magnesium Composites Produced by the Microwave Sintering Method.

In this study, magnesium composites with nano-size boron nitride (BN) particulates of varying contents were synthesized using the powder metallurgy (PM) technique incorporating microwave-assisted two-directional sintering followed by hot extrusion. The effect of nano-BN addition on the microstructural and the mechanical behavior of the developed Mg/BN composites were studied in comparison with pure Mg using the structure-property correlation. Microstructural characterization revealed uniform distribution of nano-BN particulates and marginal grain refinement. The coefficient of thermal expansion (CTE) value of the magnesium matrix was improved with the addition of nano-sized BN particulates. The results of XRD studies indicate basal texture weakening with an increase in nano-BN addition. The composites showed improved mechanical properties measured under micro-indentation, tension and compression loading. While the tensile yield strength improvement was marginal, a significant increase in compressive yield strength was observed. This resulted in the reduction of tension-compression yield asymmetry and can be attributed to the weakening of the strong basal texture.

A clinical and epidemiological study of an epidemic of non-A non-B hepatitis in Rangoon.

A total of 519 cases of viral hepatitis were admitted to the Infectious Diseases Hospital from June to October 1982 during an epidemic in Rangoon; 399 cases were found to be hepatitis non-A non-B, 84 cases were hepatitis B and 36 cases were hepatitis A. A clinical study was done of the 399 non-A non-B hepatitis cases. Also a prospective study of 434 households made up of 217 non-A non-B hepatitis cases with their families, together with 217 matched control families were followed up for a period of seven months to detect secondary cases among the family members. Non-A non-B hepatitis was found to occur most in adults of 20-40 years. Non-A non-B hepatitis is indistinguishable from the other two types of viral hepatitis. Case fatality rate was the highest in pregnant women with non-A non-B hepatitis. The field study suggested non-A non-B hepatitis can be transmitted by intrafamily spread. No evidence of sexual or syringe transmission of non-A non-B hepatitis was found.