169 research outputs found

    The Impact of Stealthy Attacks on Smart Grid Performance: Tradeoffs and Implications

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    The smart grid is envisioned to significantly enhance the efficiency of energy consumption, by utilizing two-way communication channels between consumers and operators. For example, operators can opportunistically leverage the delay tolerance of energy demands in order to balance the energy load over time, and hence, reduce the total operational cost. This opportunity, however, comes with security threats, as the grid becomes more vulnerable to cyber-attacks. In this paper, we study the impact of such malicious cyber-attacks on the energy efficiency of the grid in a simplified setup. More precisely, we consider a simple model where the energy demands of the smart grid consumers are intercepted and altered by an active attacker before they arrive at the operator, who is equipped with limited intrusion detection capabilities. We formulate the resulting optimization problems faced by the operator and the attacker and propose several scheduling and attack strategies for both parties. Interestingly, our results show that, as opposed to facilitating cost reduction in the smart grid, increasing the delay tolerance of the energy demands potentially allows the attacker to force increased costs on the system. This highlights the need for carefully constructed and robust intrusion detection mechanisms at the operator.Comment: Technical report - this work was accepted to IEEE Transactions on Control of Network Systems, 2016. arXiv admin note: substantial text overlap with arXiv:1209.176

    Viral Hepatitis A to E in South Mediterranean Countries

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    Viral hepatitis represents an important health problem in the South Mediterranean countries, Egypt, Libya, Tunisia, Algeria and Morocco. Emerging natural history and epidemiological information reveal differences in the overall epidemiology, risk factors and modes of transmission of viral hepatitis A, B, C, D, E infections in the South Mediterranean region. The differences in the in incidence and prevalence of viral hepatitis across North African countries is attributed to variations in health care and sanitation standards, risk factors and immunization strategies. The active continuous population movement through travel, tourism and migration from and to the South Mediterranean countries contribute to the spread of infections due to hepatitis viruses across borders leading to outbreaks and emergence of new patterns of infection or introduction of uncommon genotypes in other countries, particularly in Europe

    EFFECT OF PRE-SOWING TREATMENTS, SEED ORIENTATION AND THEIR INTERACTIONS ON SEED GERMINATION AND SEEDLING GROWTH OF AFRICAN MAHOGANY (KHAYA SENEGALENSIS (DESR.) A. JUSS) TREE

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    An investigation was consummated under shade condition at the nursery of Orman Botanical Garden, Giza, Egypt during 2020 and 2021 seasons to study the effect of pre-sowing treatments; i.e. seeds without any treatment (as control), soaking in tap water for 24 h at ambient temperature and soaking in hot water (70-80 °C) for 24 h, seed orientation treatments; horizontal with the micropyle oriented laterally and vertical with the micropyle positioned either upwards or downwards and their interactions on germination characters and seedling growth traits of African mahogany timber tree (Khaya senegalensis (Desr.) A. Juss) seeds. The results indicated that seeds soaked in hot water for 24 h failed to germinate in both seasons, while those soaked in tap water at room temperature for 24 h gave the highest percent of germination, the least No. days to either maximum or 50% germination as well as the best means of germination rate index, vigour index, seed viability and plumule length compared to control in the two seasons. Horizontal sowing method recorded the maximal germination percent, quickest germination, strongest vigour index and seed viability as well as the longest plumule length and followed by vertical one, in which the micropyle oriented upwards. So, the best results at all were obtained from combining soaking the seeds in tap water treatment and positioned them horizontally. A similar trend to that of germination characteristics was also occurred regarding seedling growth parameters. Accordingly, it can be proposed to soak Khaya senegalensis seeds in ordinary water pre-sowing for 24 h at ambient temperature and embedding them horizontally at 2 cm depth with the micropyle positioned laterally to obtain better germination and the best growth traits of the seedling

    Methods for selecting the best evidence to inform a NICE technology appraisal on selective internal radiation therapies for hepatocellular carcinoma

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    Background: Systematic reviews of medical devices are particularly challenging as the quality of evidence tends to be more limited than evidence on pharmaceutical products. This article describes the methods used to identify, select and critically appraise the best available evidence on selective internal radiation therapy devices for treating hepatocellular carcinoma, to inform a technology appraisal for the National Institute for Health and Care Excellence. Methods: A comprehensive search of ten medical databases and six grey literature sources was undertaken to identify studies of three devices (TheraSphere®, SIR-Spheres® and QuiremSpheres®) for treating hepatocellular carcinoma. The large evidence base was scoped before deciding what level of evidence to include for data extraction and critical appraisal. The methodological quality of the included studies was assessed using criteria relevant to each study design. Results: Electronic searches identified 4755 records; over 1000 met eligibility criteria after screening titles and abstracts. A hierarchical process was used to scope these records, prioritising comparative studies over non-comparative studies, where available. 194 full papers were ordered; 64 met the eligibility criteria. For each intervention, studies were prioritised by study design and applicability to current UK practice, resulting in 20 studies subjected to critical appraisal and data extraction. Only two trials had a low overall risk of bias. In view of the poor quality of the research evidence, our technology appraisal focused on the two higher quality trials, including a thorough critique of their reliability and generalisability to current UK practice. The 18 poorer quality studies were briefly summarised; many were very small and results were often contradictory. No definitive conclusions could be drawn from the poorer quality research evidence available. Conclusions: A systematic, pragmatic process was used to select and critically appraise the vast quantity of research evidence available in order to present the most reliable evidence on which to develop recommendations

    Paper-based sensors for rapid detection of virulence factor produced by Pseudomonas aeruginosa

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    Pyocyanin is a toxin produced by Pseudomonas aeruginosa. Here we describe a novel paper-based electrochemical sensor for pyocyanin detection, manufactured with a simple and inexpensive approach based on electrode printing on paper. The resulting sensors constitute an effective electrochemical method to quantify pyocyanin in bacterial cultures without the conventional time consuming pretreatment of the samples. The electrochemical properties of the paper-based sensors were evaluated by ferri/ferrocyanide as a redox mediator, and showed reliable sensing performance. The paper-based sensors readily allow for the determination of pyocyanin in bacterial cultures with high reproducibility, achieving a limit of detection of 95 nM and a sensitivity of 4.30 ÎĽA/ÎĽM in standard culture media. Compared to the similar commercial ceramic based sensors, it is a 2.3-fold enhanced performance. The simple in-house fabrication of sensors for pyocyanin quantification allows researchers to understand in vitro adaptation of P. aeruginosa infections via rapid screenings of bacterial cultures that otherwise are expensive and time-consuming

    Inhibition by anandamide of gap junctions and intercellular calcium signalling in striatal astrocytes

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    Anandamide, an endogenous arachidonic acid derivative that is released from neurons and activates cannabinoid receptors, may act as a transcellular cannabimimetic messenger in the central nervous system. The biological actions of anandamide and the identity of its target cells are, however, still poorly documented. Here we show that anandamide is a potent inhibitor of gap-junction conductance and dye permeability in striatal astrocytes. This inhibitory effect is specific for anandamide as compared to co-released congeners or structural analogues, is sensitive to pertussis toxin and to protein-alkylating agents, and is neither mimicked by cannabinoid-receptor agonists nor prevented by a cannabinoid-receptor antagonist. Glutamate released from neurons evokes calcium waves in astrocytes that propagate via gap junctions, and may, in turn, activate neurons distant from their initiation sites in astrocytes. We find that anandamide blocks the propagation of astrocyte calcium waves generated by either mechanical stimulation or local glutamate application. Thus, by regulating gap-junction permeability, anandamide may control intercellular communication in astrocytes and therefore neuron-glial interactions

    Liver transplantation is a preferable alternative to palliative therapy for selected patients with advanced hepatocellular carcinoma

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    Background: Patients with hepatocellular carcinoma (HCC) beyond the traditional criteria (advanced HCC) are typically offered palliation, which is associated with a 3-year survival rate lower than 30%. This study aimed to describe the outcomes for a subset of patients with advanced HCC who satisfied the Extended Toronto Criteria (ETC) and were listed for liver transplantation (LT). Materials & Methods: All patients listed in the Toronto liver transplant program with HCC beyond both the Milan and University of California, San Francisco criteria were included in this study. Data were extracted from the prospectively collected electronic database. All radiological images were reviewed by two independent radiologists. The primary endpoint was patient survival. Results: Between January 1999 and August 2014, 96 patients with advanced HCC were listed for LT, and 62 (65%) of these patients received bridging therapy while on the waiting list. Bridging therapy led to a significant reduction in tumor progression (p=0.02) and tumor burden (p <0.001). The majority of those listed underwent LT (n=69, 72%). Both tumor progression on waiting list (HR 4.973 [1.599 – 15.464], p=0.006) and peak AFP ≥400ng/ml (HR 4.604 [1.660 – 12.768], p=0.003) were independently associated with waiting list dropout. Post-LT HCC recurrence occurred in 35% (n=24). Among those with HCC recurrence, survival was significantly better for those who received curative treatment (p=0.004). The overall actuarial survival rates from the listing were 76% at 1 year, 56% at 3 years, and 47% at 5 years, and the corresponding rates from LT were 93%, 71%, and 66%. Conclusion: LT provides significantly better survival rates than palliation for patients with selected advanced HCC

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Background: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. // Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. // Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. // Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030
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