Lower Unit Research Articles

Effect of steel fiber reinforced concrete on the heavy-weight floor impact sound performance

ABSTRACT In South Korea, where apartment buildings in which the slabs of each unit are shared by the upper and lower floor units have become common, noises due to the floor impact sound from slabs between upper and lower floor units are coming to the fore as a serious social problem. The purpose of this study is to develop a method to improve the heavy- weight impact sound performance by increasing the stiffness of structural members using steel fiber reinforced concrete in order to reduce the impact sound of building floor slabs. Steel fiber reinforced concrete can increase the effective stiffness compared to ordinary reinforced concrete by suppressing cracks under the service load and is expected to reduce the heavy-weight impact sound in proportion to the stiffness through the foregoing. In this study, heavy-weight floor impact sound experiments were conducted using the compressive strength of concrete, the shape and amount of steel fibers included, and whether cracks occurred in the slab or not as variables, and the effects of the variables were analyzed. A total of nine slab specimens were fabricated, and floor impact sound experiments were conducted twice with each specimen, once before cracks occurred and once after cracks were caused by applying the service load. Therefore, a total of 18 floor impact sound experiments were conducted. As a result of the experiments, the inclusion of steel fibers was evaluated to enable the suppression of cracks under the service load, and the resultant increase in the effective stiffness was evaluated to enable the reduction of the heavy-weight impact sound of the bare slabs by up to 2 dB. The results of this study are judged to be a more efficient construction method than the existing method that increases the slab thickness, which is generally used as a method for reducing the heavy-weight floor impact sound of buildings.

An Empirical Study on the Determinants of Housing Prices in Beijing and Model Optimization

This paper aims to investigate the potential factors influencing housing prices in Beijing and optimize the prediction model. Using the Kaggle dataset "Housing Price in Beijing", multiple factors affecting housing prices were examined, including square footage, bedroom count, bathroom count, follower count, the presence of an elevator, and subway proximity. The study initially established a multiple linear regression model (MLR) and then optimized the model through variable selection and hypothesis testing. The final model indicates that square footage, bathroom count, follower count, elevator presence, and subway accessibility significantly impact housing prices. Additionally, subway proximity positively correlates with housing prices, while increased square footage is negatively associated with price, possibly due to lower unit costs for larger properties and the higher market demand for smaller homes. By validating the model's performance using a test dataset, the final model demonstrates effective predictive capability and offers insights for future model improvements.

Cost of integrated immunization campaigns in Nigeria and Sierra Leone: bottom-up costing studies

BackgroundTo improve the efficient use of scarce resources, low- and middle-income countries and development partners are increasingly encouraged to deliver multiple vaccines and other interventions in a single integrated campaign. However, little is known regarding the cost of delivering vaccines through integrated campaigns, and the extent to which efficiencies are achieved. To fill this evidence gap, we estimated the cost of integrated immunization campaigns in Nigeria and Sierra Leone, and the potential savings from integration.MethodsWe conducted a retrospective ingredients-based costing study from a payer perspective of a campaign held in 2019 in Sierra Leone with measles-rubella vaccine and oral polio vaccine, during which nutrition supplements were also offered in part of the country, and yellow fever campaigns held in three states in Nigeria in 2019 and 2020, where in one state (Anambra) meningococcal A vaccines were co-delivered. We collected data from 108 health facilities, all relevant administrative levels, and implementing partners. We estimated the full financial and economic cost of each campaign, the average unit cost of delivery, as well as the cost by activity and resource type. We also estimated the cost savings from integration in Anambra state by modelling out the cost of the alternative of two standalone campaigns.ResultsThe average financial delivery cost was $0.34 per dose in Sierra Leone, and the economic cost was $0.73 per dose. In Nigeria, the financial cost per dose was $0.29–$0.35 across the three states, and the economic cost per dose was $0.62–$0.85. Facilities and wards delivering more doses achieved a lower financial and economic unit cost of delivery, demonstrating evidence of economies of scale. We estimated that Anambra may have saved at least $1,204,133 in financial resources by integrating yellow fever and meningitis A vaccine delivery, amounting to $0.17 per dose delivered. When including opportunity costs, the economic cost saving was estimated at $0.34 per dose delivered.ConclusionsThe study offers evidence on what it costs to deliver integrated campaigns, and shows that integrated delivery is likely to result in significant cost savings. Where high delivery volumes can be achieved, integrated campaigns can benefit from economies of scale. The findings can be used to inform planning and budgeting for immunization campaigns in low- and middle-income countries.

Study on heat storage characteristics and carbon optimisation in the sintering process

In response to the phenomenon of automatic heat storage during the sintering process of iron ore, heat balance analysis concerning the main chemical reactions and physical heat carried by gas and solid materials was conducted. A unit heat storage model for the sintering process was established. Further, a mathematical model to solve the heat transfer characteristics between different sintering layer units was proposed and established based on temperature–time curves of the gas and solid phases. Using these models, the heat storage of each layer unit was calculated under the condition of uniform carbon allocation. Subsequently, the optimisation of carbon allocation at each layer unit for maximising the utilisation of heat storage was investigated. The heat required for sintering by the layer unit was taken as the constraint, and the maximum utilisation of heat stored in each layer unit was taken as the goal to optimise the carbon allocation in the height direction. The calculation results show that as the unit thickness is 100 mm and the total thickness of the layer is 600 mm, the heat transfer ratio of the upper unit to the lower unit is 34.22%, 30.29%, 14.74%, 9.49%, and 1.17%, respectively. The heat storage and available heat storage rate increase with the increase of layer height, with heat storage ranging from 0.69 × 104 to 5.14 × 104 KJ/t and heat storage rate ranging from 11.63% to 49.37%. After optimising carbon allocation, the unit achieved a maximum carbon reduction of 60.04%, resulting in an overall reduction in carbon allocation of 46.20%. This adjustment aligns more closely with the industrial processes.

CO2 delivery techniques in mini-sternotomy surgery and neurological events: a multicentric study

BackgroundThe impact of air bubbles into the cerebral circulation after open heart surgery has been a topic of discussion since the introduction of the heart-lung machine. The aim of the study was to evaluate whether the use of a dedicated commercial sponge diffuser is better than a custom-made narrow section cannula or the absence of CO2 in preventing neurological events after aortic valve replacement via J mini-sternotomy.MethodsThree cohorts of J-shaped mini-sternotomy performed at three different centers were prospectively compared: CO2 supplied via sponge diffuser, CO2 supplied via cannula, and no CO2 supply. Propensity matching was used to obtain comparable groups. The primary endpoints were postoperative stroke, transitory ischemic attack, convulsions, and dizziness. Secondary endpoints were 30-day mortality, duration of mechanical ventilation, and intensive care unit length of stay.Results275 patients were enrolled in the study. After propensity matching, the sponge diffuser cohort had a significantly lower duration of mechanical ventilation (P < 0.001) and 30-day mortality (P = 0.05) when compared to the cannula cohort and the no-CO2 cohort, a lower incidence of all neurological events (P = 0.03) and dizziness (P = 0.05) when compare to the no-CO2 cohort, and a lower intensive care unit length of stay when compared to the cannula cohort (P = 0.001).ConclusionsThe sponge diffuser used to deliver the CO2 into the surgical field during aortic valve replacement via J mini-sternotomy has been demonstrated to guarantee better neurological outcomes compared to a custom-made narrow section cannula or the absence of CO2.

Social epidemiology of urban COVID-19 inequalities in Latin America and Canada

BackgroundThe COVID-19 pandemic has spread through pre-existing fault lines in societies, deepening structural barriers faced by precarious workers, low-income populations, and racialized communities in lower income sub-city units. Many studies have quantified the magnitude of inequalities in COVID-19 distribution within cities, but few have taken an international comparative approach to draw inferences on the ways urban epidemics are shaped by social determinants of health.MethodsGuided by critical epidemiology, this study quantifies sub-city unit-level COVID-19 inequalities across eight of the largest metropolitan areas of Latin America and Canada. Leveraging new open-data sources, we use concentration indices to quantify income- and vulnerability-related inequalities in incidence, test positivity, and deaths over the first 125 weeks of the pandemic between January 2020 and May 2022.ResultsOur findings demonstrate that incidence, deaths, and test positivity are all less concentrated in low-income sub-city units than would be expected, with incidence ranging concentration in lower income neighbourhoods in Toronto (CI = -0.07) to concentration in higher income neighbourhoods in Mexico City (CI = 0.33). Drawing on relevant studies and evaluations of data reliability, we conclude that the best available public surveillance data for the largest cities in Latin America are likely not reliable measures of the true COVID-19 disease burden. We also identify recurring trends in the evolution of inequalities across most cities, concluding that higher income sub-city units were frequent early epicentres of COVID-19 transmission across the Latin America and Canada.ConclusionsJust as critical epidemiology points to individuals biologically embodying the material and social conditions in which we live, it may be just as useful to think of cities reifying their material and social inequities in the form of sub-city unit-level infectious disease inequities. By shifting away from a typical vulnerability-based social determinants of health frame, policymakers could act to redress and reduce externalities stemming from sub-city unit-level income inequality through redistributive and equity-promoting policies to shift the centre of gravity of urban health inequalities before the next infectious disease epidemic occurs.

Палеотектонический анализ отложений нижнеапшеронской литофациальной пачки Астраханского Прикаспия

The paleotectonic analysis of the Apsheron deposits of the Astrakhan Caspian Sia is considered. The main at-tention is paid to the analysis of the deposits of the lower Apsheron lithofacies unit, which includes the study of the thickness of the deposits, the construction of maps of thicknesses and trend values, as well as the analysis of the wave pattern of seismic works carried out in the territory of the Astrakhan Caspian Sia. The results of the study showed that during the Lower Apsheron time, significant tectonic processes took place in the region, including the growth of salt domes and the formation of alluvial fans. These processes had a significant impact on sedimentation and the distribution of sediment thicknesses. The conclusions about the influence of salt dome tectonics on sedimentation, as well as the role of paleorelief in the formation of local thickness anomalies are presented as well. The results obtained are important for understanding the geological history of the region and assessing its oil and gas potential. The data presented in the article are based on the analysis of geological data, including seismic data, and the use of paleotectonic analysis methods. The article describes in detail the research methods and provides examples of specific results obtained during the work.

Examining Disparities in Regional Anesthesia Utilization, Opioid Prescriptions, and Pain Scores Among Patients Who Received Primary or Revision Total Knee Arthroplasty at a Veterans Affairs Medical Center: A Retrospective Cohort Study.

Total knee arthroplasty (TKA) is one of the most performed surgical operations in the United States. Managing postoperative pain after TKA is of vital importance, as it is positively associated with outcome measures related to recovery of function and quality of life. Two commonly used methods to control postoperative pain are regional anesthesia (RA), consisting of a single or a combination of peripheral nerve and epidural blocks, and pain medication, such as opioids. Our retrospective analysis sought to better understand whether revision versus primary TKA impacted previously discovered disparities in perioperative pain management and use of RA at the Atlanta Veterans Affairs Health Care System (AVAHCS). Before data collection, we hypothesized that revision TKA would have a higher proportion of Black and older patients and that revision TKA patients would have lower postoperative pain scores. This was a retrospective analysis of AVAHCS patients who underwent elective unilateral primary or revision TKA surgery between 2014 and 2020. After application of our exclusion criteria, data from 562 patients were analyzed. Data collected included demographics information, type of RA used, and pain scores. Statistical analyses included chi-square test, t-tests, multiple logistic regression, and multiple linear regression, as appropriate to the outcomes of interest. Revision TKA patients were more likely to be Black (P = .018) and younger (P = .023 for <50 years of age group, P = .006 for 50 to 64 years of age compared to the >65 years group). Black patients, compared to White patients, had significantly higher pain scores at baseline (P = .0086) and at 24 hours postsurgery (P = .0037). Older patients (≥50 years old) had significantly higher baseline pain scores (P = .021 for the 50 to 64 years group, P < .01 for the >65 years group) and significantly lower first postanesthesia care unit pain scores (P < .05). Black race (P < .01) and age > 65 years (P < .01) were associated with a significant decrease in total oral morphine equivalents (OME) prescribed at discharge. None of the predictor variables-race, age, type of surgery (primary versus revision), baseline, and first postanesthesia care unit pain scores-were significantly associated with the use of RA in our cohort. Sociodemographic disparities in pain management have been reported in all healthcare systems, including the VAHCS. This moderately sized retrospective study, conducted at a single veterans affairs site, yielded several noteworthy findings. One finding of particular interest was that, despite Black patients reporting higher baseline and 24-hour postoperative pain scores, they were prescribed fewer opioids at discharge. Our results highlight the presence of clinically significant disparities in perioperative TKA pain management, emphasizing the need for continuous investigation and focused mitigation efforts among Veterans.

Effects of Intraoperative Opioid Use and a Combined Anesthesia Protocol in Patients Undergoing Radical Cystectomy for Urothelial Carcinoma of the Bladder—A Single-Center Experience

Background: An increased intraoperative opioid dose seems to lead to worse outcomes in several types of cancer. We assessed the effect of intraoperatively administered opioids as well as the type of anesthesia on survival, recurrence rates and major perioperative outcomes in patients who underwent radical cystectomy (RC) for urothelial carcinoma of the urinary bladder. Methods: We included patients who underwent open RC at our center between 2015 and 2022. The role of the type and dosage of intraoperative opioid agents, such as remifentanil, sufentanil and morphine milligram equivalents (MME), as well as the type of anesthesia (intravenous only versus intravenous/epidural), was assessed regarding perioperative and long-term outcomes after RC. Results: A total of 508 patients with a median age of 73 years (IQR: 64–78) were included. Overall, 92 (18%) patients received intravenous anesthesia, whereas 416 (82%) received combined anesthesia. At a median follow-up of 270 days (IQR: 98–808), 108 (21%) deaths and 106 (21%) recurrences occurred. Combined anesthesia was associated with better survival (HR:0.63, 95% CI: 0.4–0.97, p = 0.037) and lower intensive care unit admission rates (OR: 0.49, 95% CI: 0.31–0.77, p = 0.002) in the univariate analysis (unadjusted). The type and dosage of intraoperative opioid agents did not affect long-term survival and recurrence rates, as well as major perioperative outcomes. Nevertheless, the findings of our study were limited by its single-center, retrospective design. Conclusion: The use of intraoperative opioids was not associated with worse outcomes in our cohort, while the use of additional epidural anesthesia seems to be beneficial in terms of overall survival and intensive care unit admissions. Nevertheless, further research is mandatory to validate the safety of opioids in patients undergoing RC.

Improving Performance in Surgical department through Communicating Information to Decision Makers: Intervention Study in a tertiary Hospital

Hospital performance evaluation is crucial for early detection of pitfalls, and problem-solving. Data shouldn’t be passively collected. They must be measured and understood through an underlying conceptual framework. Purpose: The General Surgical Department in collaboration with the Public Health Department had the objective of developing a module for periodic monitoring and evaluation of the eight general surgical units based on calculated key performance indicators (KPIs), Composite Indices (CIs) and communication of growing out information through policy briefs directed to the heads of units for better resources allocation and evidence based decision making. Methodology: An operations research using pre-post intervention design. The exploratory component was completed in six months in the 8 units of the department. Pretest service statistical data analyzed KPIs derived from hospital bed and surgical room utilization. Data were utilized for the calculation of 5 CIs for each unit. Study intervention included the development of policy briefs (PB) that were submitted to the head of the department. Informed decisions were made guided by the info-graph data in the form of traffic color coded ranking matrix to promote various services and to improve performance in the department units particularly lower ranked units. The post-test included reanalyzing of the service statistical data. Findings: Comparing pre-posttest figures revealed improvement in the calculated KPIs and CIs. Originality and practical implications: Bringing up a novel, feasible monitoring and evaluation model using refitted tools would support surgical unit heads in evidence-based decision-making and eventually improve performance efficiency.

6861 Pre- And Peri-Operative Predictors Of Glycemic Outcomes From Total Pancreatectomy And Islet Auto-Transplantation

Abstract Disclosure: E.N. Haddad: None. M. Lansang: None. H. Xiao: None. R. Walsh: None. R. Simon: None. B.A. Hatipoglu: None. K. Zhou: None. Background: There is a lack of information regarding the immediate post-operative period as a predictor of early and long-term insulin independence after total pancreatectomy and islet auto-transplantation (TPIAT). This study examined the baseline and peri-operative variables that are associated with one-year and longer-term insulin independence following TPIAT. Methods: This was a retrospective study of 46 TPIAT patients in a single hospital system between 2010 and 2022. Perioperative variables were compared between short- (one year) and long-term (last follow up outside of year one) insulin-independent versus dependent patients. Multivariable models were used to adjust for clinically important variables. Results: The median age of the cohort at time of TPIAT was 38.5 years (IQR 30, 49). Patients were predominantly white (91%) and 50% were female. Nine (20%) and seven (15%) patients achieved short- and long-term insulin independence, respectively. The patients were followed for a median of 2.8 years (IQR 1.0, 4.7). There were no significant differences in patient demographics (age, sex, ethnicity), duration of pancreatitis, HbA1c, or mixed meal testing results (area under c-peptide curve from 0 to 4 hours) between those achieving insulin independence and those who did not. Short term insulin-independence was associated with higher median transplanted islet equivalents (IEQ)/kg (6,981 vs 4,493, p=0.02), lower units of basal insulin on discharge (7 vs 12, p=0.009), and lower rates of discharge from the hospital with an insulin regimen (67% vs 100%, p=0.006). Short-term insulin independence was also associated with decreased median insulin use in the immediate 24-hour post-operative period (14.3 vs 45.3 units, p=0.03), though this was not statistically significant when adjusting for patient weight (0.23 vs 0.56 units/kg, p=0.13). The odds of having short term insulin independence increased by 80% for every 1,000 increase in IEQ/kg (OR 1.80, CI 1.18 to 3.12, p=0.005) and decreased by 32% for every additional basal unit of insulin on discharge (OR 0.68, CI 0.42 to 0.91, p=0.003). This was no longer statistically significant after adjusting for sex, age, mixed meal testing area under c-peptide curve at 4 hours, and HbA1c. Long-term insulin independence was also associated with transplanted IEQ/kg and basal insulin units at discharge in univariable analysis. None of the patients on insulin or any other antihyperglycemic medication prior to surgery achieved short- or long-term insulin independence. Conclusion: Short- and long-term insulin independence after TPIAT is associated with a higher transplanted IEQ/kg and fewer units of basal insulin at discharge. Immediate post-operative variables can be used to inform the discussions clinicians have with their patients regarding glycemic prognosis following TPIAT. Presentation: 6/2/2024

Design of Intelligent Firefighting and Smart Escape Route Planning System Based on Improved Ant Colony Algorithm.

Due to the lack of real-time planning for fire escape routes in large buildings, the current route planning methods fail to adequately consider factors related to the fire situation. This study introduces a real-time fire monitoring and dynamic path planning system based on an improved ant colony algorithm, comprising a hierarchical arrangement of upper and lower computing units. The lower unit employs an array of sensors to collect environmental data in real time, which is subsequently transmitted to an upper-level computer equipped with LabVIEW. Following a comprehensive data analysis, pertinent visualizations are presented. Capitalizing on the acquired fire situational awareness, a propagation model for fire spreading is developed. An enhanced ant colony algorithm is then deployed to calculate and plan escape routes by introducing a fire spread model to enhance the accuracy of escape route planning and incorporating the A* algorithm to improve the convergence speed of the ant colony algorithm. In response to potential anomalies in sensor data under elevated temperature conditions, a correction model for data integrity is proposed. The real-time depiction of escape routes is facilitated through the integration of LabVIEW2018 and MATLAB2023a, ensuring the dependability and safety of the path planning process. Empirical results demonstrate the system's capability to perform real-time fire surveillance coupled with efficient escape route planning. When benchmarked against the traditional ant colony algorithm, the refined version exhibits expedited convergence, augmented real-time performance, and effectuates an average reduction of 17.1% in the length of the escape trajectory. Such advancements contribute significantly to enhancing evacuation efficiency and minimizing potential casualties.

A Dosimetric Comparison Study for Blood Irradiation Employing Different Medium and Algorithms in Clinical Linear Accelerator.

To identify a suitable approach for blood irradiation other than the commonly used water medium and to study the impact of different algorithm dose computations. Water is the commonly used medium for blood irradiation. In this study computed tomography scans were taken with locally made blood irradiation phantoms other than water, by using air, rice powder and thermocole using parallel beam for 25 Gy. Plans were recalculated for different algorithms such as collapsed cone (CC), Monte Carlo (MC) and pencil beam (PB). The dose-volume parameters and measured doses were collected and analyzed for each medium and algorithm. The monitor unit (MU) for rice powder and water are close (2461±57 and 2469±61, respectively), with a maximum dose of 28.0±1.8 and 28.0±1.9 Gy. The PB algorithm resulted in lower monitor unit values regardless of the medium used, generating values of 2418, 2406, 2382, and 2362 for water, rice powder, air, and Thermocol, respectively. A significant increase in dose was observed irrespective of the medium used when the MC algorithm was employed, with a maximum of 30.26 Gy in rice powder; a smaller dose was used when the CC algorithm was employed, with 26.3 Gy in water medium. The average maximum doses of all groups were equal using the one-way Anova statistical test. Regarding the impact of field size, rice powder appears to have consistent doses across various field sizes, with slight increases as field size grows, which is similar to water. While water is the conventional medium, this study highlights the potential benefits of rice powder, such as eliminating the risks associated with bubble formation and water spillage, which can lead to equipment malfunction and safety hazards. Although previous studies have explored rice powder as a bolus and tissue-equivalent material, this study uniquely applies this knowledge to blood irradiation, an area where rice powder has not been thoroughly investigated.

Dynamic analysis of green hydrogen production integrated with storage tanks: An economical assessment for different demands

The current study aims to investigate green hydrogen production by wind and solar energy with different hydrogen storage scenarios, taking into account the economic factors. The considered renewable energy sources (RESs) are a 3 MW wind turbine and a 3.54 MW solar photovoltaic (PV) system. System modeling is performed in TRNSYS, supplying the energy required by an electrolyzer. The goal of this research is to determine an optimal economic scenario using sensitivity analysis under the same electrolyzer capacity and renewable energy generation. The calculations for various hydrogen storage scenarios are examined and evaluated for different hydrogen sale prices ranging from 3 to 15 $/kg. Hydrogen production is sized with different storage scenarios and various demands under 200 bar and 350 bar pressures and on-grid/off-grid scenarios. Results show that for a 15 $/kg hydrogen price, the optimal scenario for hydrogen demand is 350 Nm³/hr in the on-grid scenario with a pressure of 350 bar. Likewise, for the rest of the considered hydrogen sale prices, the results are presented through a comprehensive study of different approaches. The results show that for lower hydrogen unit prices, the smaller tanks will be preferred, while for higher hydrogen prices, bigger tanks are preferred. In terms of emissions, for the same amount of hydrogen production, there will be 6350 tons of CO2 emission reduction when renewable resources are used instead of fossil fuel-based hydrogen production systems.

Timing is essential: Humoral and cellular responses to SARS-CoV-2 vaccination in a cohort of patients with auto-immune diseases treated with rituximab

Rituximab (RTX), an anti CD20 monoclonal antibody, is now a gold standard treatment for several auto-immune and chronic inflammatory diseases. Receiving RTX exposes patients to more severe infections as vaccinations become virtually inefficient in terms of B cell responses. During the COVID-19 crisis, RTX–exposed patients exhibited more severe forms of the disease, and in some cases, the introduction of RTX was delayed or avoided to protect patients as much as possible against SARS-CoV-2 infections. We retrospectively collected cellular and humoral responses from thirteen patients with dermatological and rheumatological autoimmune diseases who had been vaccinated after receiving RTX. Memory T cells subsets from patients that exposed to RTX showed few differences when compared to a cohort of healthy donors. The IFNᵧ ELISpot assay using SARS-CoV-Prot_S1 showed that eight patients exhibited a positive response that was neither correlated to the time between RTX infusion and the sampling nor to the time between RTX and the vaccination. Conversely, analysis of the SARS-CoV-2 serology showed a clearly lower binding antibody units per mL in case of recent RTX infusion. The safe threshold forconsistently positive serology was to vaccinate at least 300 days after RTX infusion (p = 0.02). Our data illustrate the difficulty in obtaining a satisfactory response to vaccination after RTX treatment within almost a year after the latest infusion, and emphasize the need to better evaluate the risk of relapses in auto-immune diseases before administering RTX in order to maintain RTX only in patients whose medical situation requires it.

Less Is More: The Role of Mesh in Microsurgical Breast Reconstruction with Abdominal Flaps.

The use of mesh to reinforce the abdominal wall after abdominal flap harvest has been reported to decrease the risk of bulging and herniation. However, the impact of the plane of mesh placement in relation to the anterior rectus sheath (vs. no mesh) on postoperative abdominal complications remains unclear. We retrospectively analyzed the length of stay and clinical outcomes in 158 female patients who underwent breast reconstruction with 250 free abdominal flaps. Group 1 consisted of patients who underwent polypropylene sublay-onlay ("sandwich") mesh placement (N = 70) versus polypropylene sublay-only mesh (group 2; N = 54) versus primary fascial repair without mesh (group 3; N = 34). Patient demographics and comorbidities were comparable between study groups, except for rates of neoadjuvant chemotherapy (group 1: 53% vs. group 2: 33% vs. group 3: 24% [p < 0.01]), postoperative follow-up in months (group 1: 21.5; group 2: 11.5; group 3: 7.6 [p < 0.01]), and length of stay in days (group 1: 4.9 vs. group 2: 4.4 vs. group 3: 3.3 [p < 0.01]). No differences were observed in breast flap and donor-site complications between study groups. Patients in group 3 required significantly lower oral morphine equivalent units postoperatively compared with those in groups 1 and 2 (group 1:185.5 vs. group 2: 79.7 vs. group 3: 71.6 [p < 0.01]). Abdominal donor-site closure without mesh was associated with a shorter length of stay and less narcotic intake without an increase in donor-site complications. These findings should be considered when deciding to place mesh for donor-site closure after abdominal flap harvest.

Characteristics of medically attended influenza infection across age groups before the COVID-19 pandemic in Lebanon

BackgroundInfluenza represents a significant global health burden for individuals and society. This study assessed the burden of medically attended influenza at a tertiary medical center in Lebanon to describe the demographics, risk factors, and outcomes prior to the COVID-19 pandemic. MethodsThis was a retrospective review of patients who tested positive for the influenza virus during three seasons between July 1, 2016 to June 30, 2019, at the American University of Beirut Medical Center. ResultsA total of 2049 patients who tested positive for influenza were analyzed. Influenza A accounted for 79.6 % of cases, and influenza B for 19.7 %, with influenza activity starting in October/November and peaking in December/January. Older age above 65 years (AOR=3.584), obesity (AOR=2.183), and chronic conditions such as chronic lung diseases (AOR=1.832), and bacterial co-infection (AOR= 2.834) were found to be independent risk factors for developing complications. Viral co-infection increased the likelihood of death tenfold. Vaccinated patients had a shorter mean hospital stay duration and a lower intensive care unit admission rate. ConclusionThe burden of medically attended influenza at our tertiary medical center in Lebanon prior to the COVID-19 pandemic was high. Vaccination decreased the likelihood of complications leading to intensive care unit admission in patients at risk.

Investigation on the Thermal–Mechanical Properties of YbRESiO5 (RE = Yb, Eu, Gd, Ho, Tm, Lu, Y, Sc): First-Principles Calculations and Thermal Performance Experiments

Environmental barrier coatings are critically needed in the future to safeguard SiC-based ceramic matrix composites (SiC CMCs) used in gas turbines. Element doping of rare earth monosilicates could further improve the properties of the coating. The crystal structure, elastic properties, and resistance to water vapor corrosion of Yb2SiO5 and YbRESiO5 (where RE = Sc, Y, Eu, Gd, Ho, Tm, Lu) were examined in this study using first-principles calculations. When RE is Yb, the material is Yb2SiO5. Based on the outcomes of the calculation, we prepared YbRESiO5 (RE = Sc, Yb, Eu) and studied the thermodynamic properties. The findings show that YbReSiO5’s resistance to water vapor corrosion is as follows: YbLuSiO5 &lt; YbEuSiO5 &lt; YbGdSiO5 &lt; YbYSiO5 &lt; Yb2SiO5 &lt; YbTmSiO5 &lt; YbHoSiO5 &lt; YbScSiO5. YbScSiO5 has a lower unit cell volume, average Re-O bond length, and thermal expansion coefficient than Yb2SiO5, while YbEuSiO5 has the reverse pattern. Moreover, of the eight materials, YbScSiO5 has the greatest elastic modulus and lattice distortion. After doping with Eu, YbEuSiO5 exhibits a decrease in thermal conductivity by nearly thirty percent compared to Yb2SiO5, due to the formation of oxygen vacancies. The development of environmental barrier coating materials may benefit from these discoveries.

Woody invaders of a temperate forest have unique root-associated fungal communities

Non-native, invasive plants are increasingly common in Eastern North American forests, but their impact on soil fungi remains unclear. We used DNA metabarcoding to investigate the effects of nativity, plant mycorrhizal type and soil factors on root-associated fungal communities. We focused on understory woody plants in a deciduous forest tract in central New York state, and included three plant types, invasive arbuscular mycorrhizal (AM), native AM, and native ectomycorrhizal (EM), each represented by 3–5 species. We found lower fungal operational taxonomic unit (OTU) diversity in EM than AM plants, but no OTU diversity difference between native and invasive AM species. Pathogen OTU richness and relative abundance were not distinct between plant types. OTU composition was influenced by host mycorrhizal type and by AM plant nativity, with mycorrhizal fungi being important drivers in both cases. The relationships of soil characteristics (e.g., pH) with OTU composition were independent of plant nativity and mycorrhizal type. Specific root length of native AM species was lower than that of invasive AM plants, while EM plants were intermediate. Irrespective of plant type, OTU composition was distinct among plant species, particularly in fungal communities associated with the invader Rhamnus cathartica. These results suggest that invasive AM plants may shift fungal composition relative to native AM and EM plants, with potential long-term consequences for soil biodiversity.

Fabrication of self‐supported catalysts via electrodeposition for proton exchange membrane water electrolysis: Emphasizing on the porous transport layers

AbstractThe potential of proton exchange membrane water electrolysis (PEMWE) is enormous in tackling worldwide environmental and energy issues in the face of increasing risks associated with climate change and energy scarcity. Nevertheless, the economic competitiveness of hydrogen production is hindered by the challenging operating conditions in acidic environments, resulting in a lower unit cost compared to alternative energy sources. Hence, numerous global research endeavors persist in enhancing the efficiency of essential components in PEMWE systems, specifically the porous transport layer (PTL). Additionally, investigating the interface between catalyst layer (CL) and PTL, which is directly associated with system performance, is imperative for future sustainability and cost reduction. This review focuses on the analysis of fabrication techniques, materials, and structural configurations to enhance the performance of PTLs. Additionally, we suggest the use of self‐supported catalysts as potential solutions to enhance mass and charge transfer at the interface between CLs and PTLs, hence facilitating the production of hydrogen on a wide scale. In the last section we provide an overview of the future trajectory and potential of next‐generation PEMWE in the context of efficient hydrogen production.