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This paper quantifies the impacts of the airframe configuration change on the performance differences between a tube-and-wing and a blended wing body aircraft. Both are sized for a 5,000 nmi design range carrying 225 passengers, initially using the same engine. Parametric geometry is created for both concepts based on relevant public information. The tube-and-wing notional geometry is derived from the existing Boeing 767-300ER, whereas JetZero’s concept inspires the blended wing body. These geometries are optimised using computational fluid dynamics and gradient-free approaches. Drag polars for each optimised model, spanning the expected operating envelope, are generated using computational fluid dynamics simulations and multi-fidelity surrogate models. Mission analysis is performed for the blended wing body, a conventional tube-and wing variant with metallic structures, and an advanced tube-and-wing with composite structures. The results show that the blended wing body operates with 15-20% higher lift-over-drag during the cruise, 24% lower fuel burn for the design mission, and 15% reduction in ramp weight relative to the conventional tube-and-wing. These differences drop to 20% for the design mission fuel burn and 10% for the ramp weight relative to the advanced tube-and-wing. When the engines are re-sized and optimised separately for each configuration, the blended wing body demonstrates a 25% improvement in block fuel and 16% reduction in ramp weight relative to the conventional tube-and-wing, which decreases to 21% and 10% relative to the advanced tube-and-wing. In both comparisons, the fuel efficiency advantage of the blended wing body decreases as the mission range is reduced.
This study examined the association between willingness-to-respond (WTR) and behavioral factors among emergency department health care workers (HCWs) during a pandemic situation in Pakistan.
Methods
A cross-sectional survey was conducted between August and September 2022, involving health care workers from 2 hospitals located in Karachi, Pakistan. Participants were recruited using a non-probability purposive sampling method. The survey instrument was designed based on Witte’s Extended Parallel Process Model (EPPM). Multivariate logistic regression analyses were used to investigate the relationship between WTR and HCWs’ attitudes, beliefs, and EPPM profiles.
Results
Health workers’ overall willingness to respond was 52.57% if required and 52.26% if asked. Female health workers showed 1.78 greater odds of WTR if required, compared to male health workers. Health workers who reported high efficacy were 21 times more likely to report to work during pandemics when required and 6 times more likely to report if asked compared to those with low efficacy.
Conclusion
This study explored health care workers’ willingness to respond during a pandemic. Female health care workers and those in clinical roles were more likely to be willing to respond during an influenza pandemic. Enhancing self-efficacy, knowledge, and addressing perceived risks can significantly improve workforce preparedness for future pandemics.
Developmental adversities early in life are associated with later psychopathology. Clustering may be a useful approach to group multiple diverse risks together and study their relation with psychopathology. To generate risk clusters of children, adolescents, and young adults, based on adverse environmental exposure and developmental characteristics, and to examine the association of risk clusters with manifest psychopathology. Participants (n = 8300) between 6 and 23 years were recruited from seven sites in India. We administered questionnaires to elicit history of previous exposure to adverse childhood environments, family history of psychiatric disorders in first-degree relatives, and a range of antenatal and postnatal adversities. We used these variables to generate risk clusters. Mini-International Neuropsychiatric Interview-5 was administered to evaluate manifest psychopathology. Two-step cluster analysis revealed two clusters designated as high-risk cluster (HRC) and low-risk cluster (LRC), comprising 4197 (50.5%) and 4103 (49.5%) participants, respectively. HRC had higher frequencies of family history of mental illness, antenatal and neonatal risk factors, developmental delays, history of migration, and exposure to adverse childhood experiences than LRC. There were significantly higher risks of any psychiatric disorder [Relative Risk (RR) = 2.0, 95% CI 1.8–2.3], externalizing (RR = 4.8, 95% CI 3.6–6.4) and internalizing disorders (RR = 2.6, 95% CI 2.2–2.9), and suicidality (2.3, 95% CI 1.8–2.8) in HRC. Social-environmental and developmental factors could classify Indian children, adolescents and young adults into homogeneous clusters at high or low risk of psychopathology. These biopsychosocial determinants of mental health may have practice, policy and research implications for people in low- and middle-income countries.
To assess the overall burden and outcomes of acute respiratory infections in paediatric inpatients with congenital heart disease (CHD).
Methods:
This is a retrospective cross-sectional study of non-neonates <1 year with CHD in the Kid’s Inpatient Database from 2012. We compared demographics, clinical characteristics, cost, length of stay, and mortality rate for those with and without respiratory infections. We also compared those with respiratory infections who had critical CHD versus non-critical CHD. Multi-variable regression analyses were done to look for associations between respiratory infections and mortality, length of stay, and cost.
Results:
Of the 28,696 infants with CHD in our sample, 26% had respiratory infections. Respiratory infection-associated hospitalisations accounted for $440 million in costs (32%) for all CHD patients. After adjusting for confounders including severity, mortality was higher for those with respiratory infections (OR 1.5, p = 0.003), estimated mean length of stay was longer (14.7 versus 12.2 days, p < 0.001), and estimated mean costs were higher ($53,760 versus $46,526, p < 0.001). Compared to infants with respiratory infections and non-critical CHD, infants with respiratory infections and critical CHD had higher mortality (4.5 versus 2.3%, p < 0.001), longer mean length of stay (20.1 versus 15.5 days, p < 0.001), and higher mean costs ($94,284 versus $52,585, p < 0.001).
Conclusion:
Acute respiratory infections are a significant burden on infant inpatients with CHD and are associated with higher mortality, costs, and longer length of stay; particularly in those with critical CHD. Future interventions should focus on reducing the burden of respiratory infections in this population.
Background: High volumes, ill patients, and steep learning curves can make neurosurgical rotations challenging for medical students. Furthermore, existing rotations often lack neurosurgery-specific orientation materials and level-appropriate pre-reading resources reducing the educational yield of short rotations. This is compounded by the lack of mandatory neurosurgical rotations across medical schools. We hypothesized that a “Neurosurgery Clerkship Manual” covering key orientation, knowledge, and practical topics would enhance educational experiences and generate sustained knowledge retention. Methods: Students rotating through neurosurgery at three hospitals were randomized to receive(intervention) or not receive(control) free access to the manual before their rotation. Participants completed surveys before, immediately after, and 4-weeks after the rotation assessing expectations, experiences, and clinically-relevant knowledge. Results: 61 participants were randomized between 2014 and 2017 with 43(70.5%) completing all three questionnaires. Baseline demographics, characteristics, and experiences were not significantly different. Those receiving the manual reported increased rotation enjoyment(p=0.02), decreased stress levels (p=0.05), and a greater feeling of being “part of the team”(p=0.01). There were also reductions in feeling like they were “not learning” (p=0.01). Finally, those receiving the manual demonstrated significantly better knowledge after the rotation (91.6%vs80.9%;p=0.04) which was sustained at 4-weeks post-rotation (89.2%vs79.0%;p=0.05). Conclusions: A simple and inexpensive clerkship manual can improve the neurosurgery rotation experience and knowledge retention for medical students.
Background: Human induced pluripotent stem cell-derived neural stem cells (hiPS-NSCs) represent an exciting therapeutic approach for traumatically spinal cord injury (SCI). Unfortunately, most patients are the in chronic injury phase where a dense perilesional chondroitin sulfate proteoglycan (CSPG) scar significantly hinders regeneration. CSPG-degrading enzymes can enhance NSC-mediated recovery, however, nonspecific intrathecal administration causes off-target effects. We aimed to genetically engineer hiPS-NSCs to express a scar-degrading ENZYME into their local environment to enhance functional recovery. Methods: A bicistronic scar-degrading ENZYME and RFP reporter vector was non-virally integrated into hiPS-NSCs and monoclonalized. ENZYME activity was assessed by WST-1 and DMMB biochemical assays and an in vitro CSPG spot assay with hiPS-NSC-derived neurons. To assess in vivo efficacy, T-cell deficient rats (N=60) with chronic (8wk) C6-7 SCIs were randomized to receive (1)SMaRT cells, (2)hiPS-NSCs, (3)vehicle, or (4)sham surgery. Results: SMaRT cells retained key hiPS-NSC characteristics while stably expressing ENZYME. The expressed ENZYME could appropriately degrade in vitro and ex vivo CSPGs. While blinded neurobehavioural and immunohistochemical assessments are ongoing at 40wks post-injury, an interim analysis demonstrated human cells extending remarkably long (≥20,000µm) axons along host white matter tracts. Conclusions: This work provides exciting proof-of-concept data that genetically-engineered SMaRT cells can degrade CSPGs and human NSCs can extend long-distance processes in chronic SCI.
Comparing genotype results of tuberculosis (TB) isolates from individuals diagnosed with TB can support or refute transmission; however, these conclusions are based upon the criteria used to define a genotype match. We used a genotype-match definition which allowed for variation in IS6110 restriction fragment length polymorphism (RFLP) to support transmission between epidemiologically linked persons. Contacts of individuals with infectious TB (index cases) diagnosed in New York City from 1997 to 2003 who subsequently developed TB (contact cases) from 1997 to 2007 were identified. For each contact case and index case (case-pair), isolate genotypes (spoligotype and RFLP results) were evaluated. Isolates from case-pairs were classified as exact or non-exact genotype match. Genotypes from non-exact match case-pairs were reviewed at the genotyping laboratory to determine if the isolates met the near-genotype-match criteria (exactly matching spoligotype and similar RFLP banding patterns). Of 118 case-pairs identified, isolates from 83 (70%) had exactly matching genotypes and 14 (12%) had nearly matching genotypes (supporting transmission), while the remaining 21 (18%) case-pairs had discordant genotypes (refuting transmission). Using identical genotype-match criteria for isolates from case-pairs epidemiologically linked through contact investigation may lead to underestimation of transmission. TB programmes should consider the value of expanding genotype-match criteria to more accurately assess transmission between such cases.
Literature surrounding the burden of and factors associated with hepatitis B virus (HBV) and hepatitis C virus (HCV) infection in persons with tuberculosis (TB) disease remains limited and focused on populations outside the USA. Cross-matched New York City (NYC) TB and viral hepatitis surveillance data were used to estimate the proportion of NYC adults diagnosed with TB from 2000 to 2010 with a report of viral hepatitis infection and to describe the impact of viral hepatitis infection on TB treatment completion and death. For 9512 TB patients, HCV infection was reported in 4·2% and HBV infection in 3·7%; <1% of TB patients had both HCV and HBV infection. The proportion of TB patients with HCV infection to die before TB treatment completion was larger than in TB patients without a viral hepatitis report (21% vs. 9%); this association remained when stratified by HIV status. There was no significant difference in death before treatment completion for TB patients with HBV infection compared to TB patients without a viral hepatitis report when stratified by HIV status. These findings reinforce the importance of hepatitis testing and providing additional support to TB patients with viral hepatitis infection.
We report an interesting case of a right temporal pre-auricular arteriovenous fistula (cirsoid aneurysm) causing intractable tinnitus successfully managed by transarterial n-butyl cyanoacrylate glue embolisation.
Case report:
A 52-year-old female presented with a one-year history of tinnitus and pulsatile swelling in the right pre-auricular region. A colour Doppler ultrasound test and magnetic resonance angiography revealed a high-flow scalp arteriovenous fistula with a feeder vessel from the distal superficial temporal artery, which drained into the corresponding, dilated, tortuous vein. The patient underwent diagnostic digital subtraction angiography. This was followed by transarterial embolisation of the fistula using a 50 per cent mixture of n-butyl cyanoacrylate glue and Lipiodol®, with manual distal venous occlusion. A successful outcome was achieved with instant relief of symptoms.
Conclusion:
Cirsoid aneurysms of the facial region, an uncommon cause of tinnitus, can be effectively managed by endovascular embolisation. This treatment obviates the need for surgery, which is associated with an increased risk of complications such as scarring, deformity and bleeding.
Presence of fever in psychiatric patients may signify a number of potentially fatal conditions. Several of these are related to treatments (e.g. neuroleptic malignant syndrome with antipsychotics, serotonin syndrome with serotonergic antidepressants, and malignant hyperpyrexia with anaesthesia used for administration of electroconvulsive therapy) or exacerbated by them (e.g. malignant catatonia with antipsychotics). New classes of drug treatment may be changing the epidemiology of these disorders. We suggest that an initial diagnosis of hyperthermia syndrome is clinically useful as there are some important commonalities in treatment. We outline a systematic approach to identify a particular subtype of hyperthermia syndrome and the indications for more specific treatments where available.
The primary objective of this investigation is to determine experimentally the sources of jet mixing noise. In the present study, four different approaches are used. It is reasonable to assume that the characteristics of the noise sources are imprinted on their radiation fields. Under this assumption, it becomes possible to analyse the characteristics of the far-field sound and then infer back to the characteristics of the sources. The first approach is to make use of the spectral and directional information measured by a single microphone in the far field. A detailed analysis of a large collection of far-field noise data has been carried out. The purpose is to identify special characteristics that can be linked directly to those of the sources. The second approach is to measure the coherence of the sound field using two microphones. The autocorrelations and cross-correlations of these measurements offer not only valuable information on the spatial structure of the noise field in the radial and polar angle directions, but also on the sources inside the jet. The third approach involves measuring the correlation between turbulence fluctuations inside a jet and the radiated noise in the far field. This is the most direct and unambiguous way of identifying the sources of jet noise. In the fourth approach, a mirror microphone is used to measure the noise source distribution along the lengths of high-speed jets. Features and trends observed in noise source strength distributions are expected to shed light on the source mechanisms. It will be shown that all four types of data indicate clearly the existence of two distinct noise sources in jets. One source of noise is the fine-scale turbulence and the other source is the large turbulence structures of the jet flow. Some of the salient features of the sound field associated with the two noise sources are reported in this paper.
Edited by
A. T. Ahuja, Prince of Wales Hospital, Hong Kong,G. E. Antonio, Prince of Wales Hospital, Hong Kong,K. T. Wong, Prince of Wales Hospital, Hong Kong,H. Y. Yuen, Prince of Wales Hospital, Hong Kong
Laboratory studies have shown that the resistance of isolated LDL-cholesterol or linoleic acid to oxidation is increased in incubations with chilli extracts or capsaicin – the active ingredient of chilli. It is unknown if these in vitro antioxidative effects also occur in the serum of individuals eating chilli regularly. The present study investigated the effects of regular consumption of chilli on in vitro serum lipoprotein oxidation and total antioxidant status (TAS) in healthy adult men and women. In a randomised cross-over study, twenty-seven participants (thirteen men and fourteen women) ate ‘freshly chopped chilli’ blend (30g/d; 55% cayenne chilli) and no chilli (bland) diets, for 4 weeks each. Use of other spices, such as cinnamon, ginger, garlic and mustard, was restricted to minimum amounts. At the end of each dietary period serum samples were analysed for lipids, lipoproteins, TAS and Cu-induced lipoprotein oxidation. Lag time (before initiation of oxidation) and rate of oxidation (slope of propagation phase) were calculated. There was no difference in the serum lipid, lipoproteins and TAS at the end of the two dietary periods. In the whole group, the rate of oxidation was significantly lower (mean difference −0·23 absorbance ×10−3/min; P=0·04) after the chilli diet, compared with the bland diet. In women, lag time was higher (mean difference 9·61min; P<0·001) after the chilli diet, compared with the bland diet. In conclusion, regular consumption of chilli for 4 weeks increases the resistance of serum lipoproteins to oxidation.
We have investigated, theoretically and experimentally, the reduced and optical bandgap shift of Si-doped AlXGa1-XAs alloys as a function of both the Al composition and the Si concentration. The calculations were carried out within a framework of the many particle random phase approximation with the Hubbard local-field correction, considering electron populations in the conduction minima located at the Γ, X and L-points of the Brillouin zone. The experimental data have been obtained by means of photoluminescence spectroscopy. The theoretical predictions are found to be in good agreement with the experimental results.
The optical properties of SbBiI3 alloys have been investigated experimentally by absorption measurements and theoretically by a full-potential augmented plane wave (FPLAPW) method within the generalized gradient approximation. The fundamental band-gap energy of these alloys changes from BiI3- to SbI3-like with increasing percentage of Sb content. The calculated band-gap energies as well as the optical absorption were found to be in a very good qualitatively agreement with the experimental results. We present calculated density-of-states as well as the dielectric functions for evaluation of future experiments.
Peritonsillar infections include cellulitis and abscess (quinsy). Clinical diagnosis is often supplemented by diagnostic drainage (aspiration or incision) in an effort to distinguish abscess from cellulitis. In a prospective study of 14 patients we have shown that clinical impression alone is unreliable (sensitivity 78 per cent, specificity 50 per cent). Computerized tomography (CT) (sensitivity 100 per cent, specificity 75 per cent) and intraoral ultrasound (sensitivity 89 per cent, specificity 100 per cent) are much more reliable. We propose that intraoral ultrasound could play a useful role in the clinical assessment of peritonsillar infections helping to improve accuracy in distinguishing abscesses from cellulitis.
In the notation of Riordan ([5], p. 33), the Stirling numbers, s(n, k) and S(n, k), of the first and second kind respectively are defined by the relation where (x)n = x(x − 1) … (x − n + 1) is the factorial power function. They have been used by Jordan ([3], p. 184) to define the numbers C(m, k) and D(m, k), as linear combinations of s(n, k) and S(n, k) respectively, given by where and and where and D(m, O.
Let X1, X2, …, Xn be n independent and identically distributed random variables having the positive binomial probability function
1
where 0 < p < 1, and T = {1, 2, …, N}. Define their sum as Y=X1 + X2 + … +Xn. The distribution of the random variable Y has been obtained by Malik [2] using the inversion formula for characteristic functions. It appears that his result needs some correction. The purpose of this note is to give an alternative derivation of the distribution of Y by applying one of the results, established by Patil [3], for the generalized power series distribution.
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