433 research outputs found

    Perverse coherent t-structures through torsion theories

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    Bezrukavnikov (later together with Arinkin) recovered the work of Deligne defining perverse tt-structures for the derived category of coherent sheaves on a projective variety. In this text we prove that these tt-structures can be obtained through tilting torsion theories as in the work of Happel, Reiten and Smal\o. This approach proves to be slightly more general as it allows us to define, in the quasi-coherent setting, similar perverse tt-structures for certain noncommutative projective planes.Comment: New revised version with important correction

    The Use of Ceramic Waste Powder (CWP) in Making Eco-Friendly Concretes

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    The global production of ceramic waste powder (CWP), which is produced during the final polishing process of ceramic tiles, exceeds 22 billion tons. The disposal of CWP in landfills will cause significant environmental problems (i.e., soil, air, and groundwater pollution). CWP is characterized by its chemical composition that is mainly composed of silica (SiO2) and alumina (Al2O3). Both minerals represent more than 80% of the CWP composition. CWP has potentials to be used as an ingredient to partially or entirely replacing Portland cement to make eco-friendly concretes. This chapter summarizes the effect of using CWP in making eco-friendly concretes, with a particular focus on using CWP as a partial cement replacement in conventional-vibrated concrete (CVC) and self-compacting concrete (SCC), and the production of zero-cement alkali-activated concrete (AAC)

    Tunable H-Shaped Microstrip Antenna with Dual Feeding

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    The design of a frequency reconfigurable dual-band H-shaped microstrip antenna fed by two coaxial probes is presented. Each probe excites one of the two fundamental modes of the antenna which are linearly polarized and orthogonal to each other. The antenna is symmetrically loaded with four varactor diodes to simultaneously tune these two modes. Simulation results show that the tunable range of the first mode is between 1.69 and 2.19 GHz (1.3 : 1 tuning ratio), whereas it is between 1.94 and 2.72 GHz (1.4 : 1 tuning ratio) for the second mode. In the range between 1.94 and 2.19 GHz, the radiation of the proposed antenna can be switched between two orthogonal linear polarizations by a simple adjustment to the capacitance of the varactor diodes. The proposed antenna achieves a good performance in terms of port-to-port isolation, directivity, and cross-polarization.</jats:p

    Effects of Electrohydraulic Therapy of Shock Waves on Pain and Lymphedema Measurement Post-Radical Mastectomy

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    Background: Lymphedema post-mastectomy remains a challenging problem. This study aimed to investigate the efficacy of shock wave electrohydraulic treatment (ESWT) for patients with pain and lymphedema. Methods: Thirty patients (30 women) with pain & lymphedema post-radical mastectomy were evaluated to participate in this Clinical trial. They were recruited from the Minia Cancer Institute- Minia University and Deraya University outpatient clinics. Their ages varied between the ages of 40 and 50 years. They were divided into two groups. Group (1) 'Group of studies': 15 patients seeking ESWT in addition to conventional medical care. Group (2) 'Control group': 15 people seeking conventional medical care only. Patients of the study group (1) were treated with a number of impulses, at least 500 shocks at E2 at 4Hz (equivalent to 0.11mJ/mm square energy). Treatment sessions were delivered twice weekly for six treatments (3 weeks). The assessment used a Visual analogue scale (VAS) for pain and arm circumference midway between the shoulder and elbow for lymphedema measurement. Results: showed that (ESWT) on pain and lymphedema measurement post-radical mastectomy effectively decreased pain as evidenced by the highly significant decreases in the visual analogue scale. These results revealed a substantial VAS reduction (P<0.0001). Effects of the ESWT on lymphedema measurement via the arm circumference measurement at the point where the shoulder and the elbow meet post-radical mastectomy were investigated. These results revealed a notable reduction in the mean value of the arm circumference measurement (ACM) (P<0.0001). Conclusion: The significant reductions in VAS and assessment of the ACM arm range show that the ESWT, in addition to conventional therapy, significantly impacted upper limb structural components following radical mastectomy

    Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

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    Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

    Evaluation of Inactivated Avian Influenza Virus and Newcastle Disease Virus Bivalent Vaccination Program Against Newly Circulated H5N8 and NDV Strains

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    Avian influenza virus (AIV) and Newcastle disease virus (NDV) are respiratory illness syndromes that have recently been detected in vaccinated flocks and are causing major financial losses in the chicken farming industry. The objective was to evaluate the efficacy of Valley Vac H5Plus NDVg7 vaccine in protecting chickens against the H5N8 and NDV strains that have recently been circulating in comparison with the efficacy of the commercially available bivalent H5+ND7 vaccine. In contrast to the H5+ND7 vaccine, which was made of genetically distinct H5N8/2018 clade 2.3.4.4b genotype group (G5), H9N2/2016, H5N1/2017, and genetically comparable NDV genotype VII 1.1/2019 of the recently circulating challenge viruses, the Valley Vac H5Plus NDVg7 vaccine consisted of the recently isolated (RG HPAI H5N1 AIV/2015 Clade 2.2.1.2, RG HPAIV H5N8/2020 Clade 2.3.4.4b genotype group 6 (G6), and NDV genotype VII 1.1/2012) which were genetically similar to challenged strains. To determine the effectiveness of the Valley Vac H5Plus NDVg7 vaccine, a total of 70-day-old commercial chicks were divided into 7 groups of 10 birds each. Groups (G1 and G4) received Valley Vac H5Plus NDVg7 vaccine. Groups (G2 and G5) groups received commercial H5+ND7 vaccine. While groups (G3 and G6) were kept nonvaccinated, and group (G7) was kept as a nonchallenged and nonvaccinated. After 3-wk post vaccination (WPV), groups G1, G2, and G3 were challenged with A/Duck/ Egypt/SMG4/2019(H5N8) genotype G6. On the other hand, groups G4, G5, G6 were challenged with NDV/EGYPT/18629F/2018 genotype VII 1.1 with an intranasal injection of 0.1 mL. Antibody titer was calculated at the first 3 wk after vaccination, and the viral shedding titer was calculated at 3-, 5-, and 7-days post challenge. Mortality and morbidity rates were monitored daily during the experiment, and for the first 10 d after the challenge, to provide an estimate of the protection rate. The results showed that a single dosage of 0.5 mL per bird of Valley Vac H5Plus NDVg7 vaccine provides 80% protection against both H5N8 and NDV, compared to the bivalent H5+ND7 vaccine, which provided 20 and 80% protection against H5N8 and NDV, respectively. In addition, 0.5 mL per bird of Valley Vac H5Plus NDVg7 vaccine produced a greater immune response against both viruses than commercial vaccination at 1 to 3 WPV with a significant difference at 1 WPV for H5N8 and a comparatively higher immune response for NDV. Furthermore, it reduced virus shedding of H5N8 on the third, fifth, seventh, and tenth days lower than H5+ND7 vaccine with a significant difference on the third day for H5N8 and relatively lower than bivalent H5+ND7 vaccine for NDV with a significant difference on the fifth day. The Valley vaccinated group demonstrated more tissue intactness compared to the commercially vaccinated group against the H5N8 challenge, however the bivalent commercially vaccinated group showed the similar level of tissue integrity against NDV. In conclusion, Valley Vac H5Plus NDVg7 that contains the genetically similar strain to recently circulating challenged virus (H5N8 genotype G6) provided better protection with greater immune response and decreased the amount of virus shed against H5N8 genotype G6 and showed less histopathological alteration than the commercial bivalent H5+ND7 vaccine that contain genetically distinct (H5N8 genotype G5). However the Valley Vac H5Plus NDVg7 provided the same protection with relatively high immune response and relatively decreased the amount of virus shed and showed equal tissue integrity than the commercial bivalent H5+ND7 vaccine against NDV genotype VII 1.1 that contain the same genotype of NDV genotype VII 1.1

    Severe early onset preeclampsia: short and long term clinical, psychosocial and biochemical aspects

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    Preeclampsia is a pregnancy specific disorder commonly defined as de novo hypertension and proteinuria after 20 weeks gestational age. It occurs in approximately 3-5% of pregnancies and it is still a major cause of both foetal and maternal morbidity and mortality worldwide1. As extensive research has not yet elucidated the aetiology of preeclampsia, there are no rational preventive or therapeutic interventions available. The only rational treatment is delivery, which benefits the mother but is not in the interest of the foetus, if remote from term. Early onset preeclampsia (<32 weeks’ gestational age) occurs in less than 1% of pregnancies. It is, however often associated with maternal morbidity as the risk of progression to severe maternal disease is inversely related with gestational age at onset2. Resulting prematurity is therefore the main cause of neonatal mortality and morbidity in patients with severe preeclampsia3. Although the discussion is ongoing, perinatal survival is suggested to be increased in patients with preterm preeclampsia by expectant, non-interventional management. This temporising treatment option to lengthen pregnancy includes the use of antihypertensive medication to control hypertension, magnesium sulphate to prevent eclampsia and corticosteroids to enhance foetal lung maturity4. With optimal maternal haemodynamic status and reassuring foetal condition this results on average in an extension of 2 weeks. Prolongation of these pregnancies is a great challenge for clinicians to balance between potential maternal risks on one the eve hand and possible foetal benefits on the other. Clinical controversies regarding prolongation of preterm preeclamptic pregnancies still exist – also taking into account that preeclampsia is the leading cause of maternal mortality in the Netherlands5 - a debate which is even more pronounced in very preterm pregnancies with questionable foetal viability6-9. Do maternal risks of prolongation of these very early pregnancies outweigh the chances of neonatal survival? Counselling of women with very early onset preeclampsia not only comprises of knowledge of the outcome of those particular pregnancies, but also knowledge of outcomes of future pregnancies of these women is of major clinical importance. This thesis opens with a review of the literature on identifiable risk factors of preeclampsia

    Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

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    BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112

    Highly Pathogenic Avian Influenza Virus (H5N8) Clade 2.3.4.4 Infection in Migratory Birds, Egypt

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    We isolated highly pathogenic avian influenza virus (H5N8) of clade 2.3.4.4 from the common coot (Fulica atra) in Egypt, documenting its introduction into Africa through migratory birds. This virus has a close genetic relationship with subtype H5N8 viruses circulating in Europe. Enhanced surveillance to detect newly emerging viruses is warranted

    A template and tutorial for preregistering studies using passive smartphone measures

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    Passive smartphone measures hold significant potential and are increasingly employed in psychological and biomedical research to capture an individual's behavior. These measures involve the near-continuous and unobtrusive collection of data from smartphones without requiring active input from participants. For example, GPS sensors are used to determine the (social) context of a person, and accelerometers to measure movement. However, utilizing passive smartphone measures presents methodological challenges during data collection and analysis. Researchers must make multiple decisions when working with such measures, which can result in different conclusions. Unfortunately, the transparency of these decision-making processes is often lacking. The implementation of open science practices is only beginning to emerge in digital phenotyping studies and varies widely across studies. Well-intentioned researchers may fail to report on some decisions due to the variety of choices that must be made. To address this issue and enhance reproducibility in digital phenotyping studies, we propose the adoption of preregistration as a way forward. Although there have been some attempts to preregister digital phenotyping studies, a template for registering such studies is currently missing. This could be problematic due to the high level of complexity that requires a well-structured template. Therefore, our objective was to develop a preregistration template that is easy to use and understandable for researchers. Additionally, we explain this template and provide resources to assist researchers in making informed decisions regarding data collection, cleaning, and analysis. Overall, we aim to make researchers' choices explicit, enhance transparency, and elevate the standards for studies utilizing passive smartphone measures
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