120 research outputs found

    Home exposure to Arabian incense (bakhour) and asthma symptoms in children: a community survey in two regions in Oman

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    <p>Abstract</p> <p>Background</p> <p>Incense burning has been reported to adversely affect respiratory health. The aim of this study was to explore whether exposure to bakhour contributes to the prevalence of asthma and/or triggers its symptoms in Omani children by comparing two Omani regions with different prevalence of asthma.</p> <p>Methods</p> <p>A randomly selected sample of 10 years old schoolchildren were surveyed using an Arabic version of ISAAC Phase II questionnaires with the addition of questions concerning the use and effect of Arabian incense on asthma symptoms. Current asthma was defined as positive response to wheeze in the past 12 months or positive response to "ever had asthma" together with a positive response to exercise wheeze or night cough in the past 12 months. Simple and multivariable logistic regression analyses were performed to estimate the effect of bakhour exposure and other variables on current asthma diagnosis and parents' response to the question: "Does exposure to bakhour affect your child breathing?"</p> <p>Results</p> <p>Of the 2441 surveyed children, 15.4% had current asthma. Bakhour use more than twice a week was three times more likely to affect child breathing compared to no bakhour use (adjusted OR 3.01; 95% CI 2.23–4.08) and this effect was 2.55 times higher in asthmatics (adjusted OR 2.55; 95% CI 1.97–3.31) compared to non-asthmatics. In addition, bakhour caused worsening of wheeze in 38% of the asthmatics, making it the fourth most common trigger factor after dust (49.2%), weather (47.6%) and respiratory tract infections (42.2%). However, there was no significant association between bakhour use and the prevalence of current asthma (adjusted OR 0.87; 95% CI 0.63–1.20).</p> <p>Conclusion</p> <p>Arabian incense burning is a common trigger of wheezing among asthmatic children in Oman. However, it is not associated with the prevalence asthma.</p

    The carbohydrate-linked phosphorylcholine of the parasitic nematode product ES-62 modulates complement activation

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    Parasitic nematodes manufacture various carbohydratelinked phosphorylcholine (PCh)-containing molecules, including ES-62, a protein with an N-linked glycan terminally substituted with PCh. The PCh component is biologically important because it is required for immunomodulatory effects. We showed that most ES-62 was bound to a single protein, C-reactive protein (CRP), in normal human serum, displaying a calcium-dependent, high-avidity interaction and ability to form large complexes. Unexpectedly, CRP binding to ES-62 failed to efficiently activate complement as far as the C3 convertase stage in comparison with PCh-BSA and PCh-containing Streptococcus pneumoniae cell wall polysaccharide. C1q capture assays demonstrated an ES-62-CRP-C1q interaction in serum. The three ligands all activated C1 and generated C4b to similar extents. However, a C2a active site was not generated following ES-62 binding to CRP, demonstrating that C2 cleavage was far less efficient for ES-62-containing complexes. We proposed that failure of C2 cleavage was due to the flexible nature of carbohydrate-bound PCh and that reduced proximity of the C1 complex was the reason that C2 was poorly cleaved. This was confirmed using synthetic analogues that were similar to ES-62 only in respect of having a flexible PCh. Furthermore, ES-62 was shown to deplete early complement components, such as the rate-limiting C4, following CRP interaction and thereby inhibit classical pathway activation. Thus, flexible PCh-glycan represents a novel mechanism for subversion of complement activation. These data illustrate the importance of the rate-limiting C4/C2 stage of complement activation and reveal a new addition to the repertoire of ES-62 immunomodulatory mechanisms with possible therapeutic applications

    Escrow-Free Encryption Supporting Cryptographic Workflow

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    Since Boneh and Franklin published their seminal paper on identity based encryption (IBE) using the Weil pairing , there has been a great deal of interest in cryptographic primitives based on elliptic-curve pairings. One particularly interesting application has been to control access to data, via possibly complex policies. In this paper we continue the research in this vein. We present an encryption scheme such that the receiver of an encrypted message can only decrypt if it satisfies a particular policy chosen by the sender at the time of encryption. Unlike standard IBE, our encryption scheme is escrow free in that no key-issuing authority (or colluding set of key-issuing authorities) is able to decrypt ciphertexts itself. In addition we describe a security model for the scenario in question and provide proofs of security for our scheme (in the random oracle model)

    An assistive and research framework methodology for ships’ upkeep and repair organisational learning performance

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    The Omani Dockyard (OD) requires the development of a research methodology, which encompasses an assistive framework to maintain the research boundary to support a research framework. A research framework is developed to understand the behaviour of variables. A deductive/quantitative – survey questionnaire is employed in the main research to statistically understand the ‘mindsets/opinions’ of a large population and an inductive/qualitative – semi-structured interview using selected senior managers for the total research. Another questionnaire was used to critically learn from the agreement of the senior managers if the proposed contributions were in line with the ships’ upkeep and repair ‘organisational performance’. The initial and most definitive requirement is also to understand the strength of independent and mediation constructs applicability for the enhancement of performance. The problem is in the area of ‘enhancement of organisational learning on knowledge and competencies’ to underpin ships’ upkeep and repair support performance for better availability of operational ships. This research methodology was designed for a ‘major piece of research’ involving a doctorate dissertation in ships’ support performance. The conclusion and recommendation for a ‘major piece of research’ formulated the framework/model to underpin performance. This study concentrates on the research methodology that was used for ships’ upkeep and repair performance of the Omani dockyard with a compressive description of the total results, which can be generalized for other studies

    The helminth product, ES-62, protects against airway inflammation by resetting the Th cell phenotype

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    We previously demonstrated inhibition of ovalbumin (OVA)-induced allergic airway hyper-responsiveness in the mouse using ES-62, a phosphorylcholine-containing glycoprotein secreted by the filarial nematode, Acanthocheilonema viteae. This inhibition correlated with ES-62-induced mast cell desensitisation, although the degree to which this reflected direct targeting of mast cells remained unclear as suppression of the Th2 phenotype of the inflammatory response, as measured by eosinophilia and IL-4 levels in the lungs, was also observed. We now show that inhibition of the lung Th2 phenotype is reflected in ex vivo analyses of draining lymph node recall cultures and accompanied by a decrease in the serum levels of total and OVA-specific IgE. Moreover, ES-62 also suppresses the lung infiltration by neutrophils that is associated with severe asthma and is generally refractory to conventional anti-inflammatory therapies, including steroids. Protection against Th2-associated airway inflammation does not reflect induction of regulatory T cell (Treg) responses (there is no increased IL-10 or Foxp3 expression) but rather a switch in polarisation towards increased T-bet expression and IFNÎł production. This ES-62-driven switch in the Th1/Th2 balance is accompanied by decreased IL-17 responses, a finding in line with reports that IFNÎł and IL-17 are counter-regulatory. Consistent with ES-62 mediating its effects via IFNÎł-mediated suppression of pathogenic Th2/Th17 responses, we found that neutralising anti-IFNÎł antibodies blocked protection against airway inflammation in terms of pro-inflammatory cell infiltration, particularly by neutrophils and lung pathology. Collectively, these studies indicate that ES-62, or more likely small molecule analogues, could have therapeutic potential in asthma, in particular for those subtypes of patients (e.g. smokers, steroid-resistant) who are refractory to current treatments

    Molecular characterization of glucose-6-phosphate dehydrogenase deficient variants in Baghdad city - Iraq

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    Background: Although G6PD deficiency is the most common genetically determined blood disorder among Iraqis, its molecular basis has only recently been studied among the Kurds in North Iraq, while studies focusing on Arabs in other parts of Iraq are still absent. Methods: A total of 1810 apparently healthy adult male blood donors were randomly recruited from the national blood transfusion center in Baghdad. They were classified into G6PD deficient and non-deficient individuals based on the results of methemoglobin reduction test (MHRT), with confirmation of deficiency by subsequent enzyme assays. DNA from deficient individuals was studied using a polymerase chain reaction-Restriction fragment length polymorphism (PCR-RFLP) for four deficient molecular variants, namely G6PD Mediterranean (563 CÂźT), Chatham (1003 GÂźA), A- (202 GÂźA) and Aures (143 TÂźC). A subset of those with the Mediterranean variant, were further investigated for the 1311 (CÂźT) silent mutation. Results: G6PD deficiency was detected in 109 of the 1810 screened male individuals (6.0%). Among 101 G6PD deficient males molecularly studied, the Mediterranean mutation was detected in 75 cases (74.3%), G6PD Chatham in 5 cases (5.0%), G6PD A- in two cases (2.0%), and G6PD Aures in none. The 1311 silent mutation was detected in 48 out of the 51 G6PD deficient males with the Mediterranean variant studied (94.1%). Conclusions: Three polymorphic variants namely: the Mediterranean, Chatham and A-, constituted more than 80% of G6PD deficient variants among males in Baghdad. Iraq. This observation is to some extent comparable to othe

    Correlates of physical activity and sitting time in adults with type 2 diabetes attending primary health care in Oman

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    Abstract Background Despite evidence of the benefits of physical activity in the management of type 2 diabetes, it is poorly addressed in diabetes care. This study aimed to identify the prevalence and correlates of meeting ≄600MET-min/wk. (150 min/wk) of physical activity and sitting time in adults with type 2 diabetes in Oman. Approaches to encourage physical activity in diabetes care were explored. Methods A cross-sectional study using the Global Physical Activity Questionnaire was conducted in 17 randomly selected primary health centres in Muscat. Clinical data including co-morbidities were extracted from the health information system. Questions on physical activity preferences and approaches were included. Patients were approached if they were ≄18 years, and had been registered in the diabetes clinic for >2 years. Results The questionnaire was completed by 305 people (females 57% and males 43%). Mean age (SD) was 57 (10.8) years and mean BMI (SD) was 31.0 (6.0) kg/m2. Duration of diabetes ranged from 2 to 25 (mean 7.6) years. Hypertension (71%) and dyslipidaemia (62%) were common comorbidities. Most (58.4%) had an HbA1c ≄7% indicating poor glycaemic control (55% in males vs 61% in females). Physical activity recommendations were met by 21.6% of the participants, mainly through leisure activities. Odds of meeting the recommendations were significantly higher in males (OR 4.8, 95% CI 2.5–9.1), individuals ≀57 years (OR 3.0, 95% CI 1.6–5.9), those at active self-reported stages of change for physical activity (OR 2.2, 95% CI 1.2–4.1) and those reporting no barriers to performing physical activity (OR 2.7, 95% CI 1.4–4.9). Median (25th, 75th percentiles) sitting time was 705 (600, 780) min/d. Older age (>57 years) was associated with longer sitting time (>705 min/d) (OR 2.8, 95% CI 1.7–4.6). Preferred methods to support physical activity in routine diabetes care were consultations (38%), structured physical activity sessions (13.4%) and referrals to physical activity facilities (5.6%) delivered by a variety of health care providers. Conclusions The results suggest that intervention strategies should take account of gender, age, opportunities within daily life to promote active behaviour and readiness to change. Offering physical activity consultations is of interest to this study population, thus development and evaluation of interventions are warranted

    Registration-Based Encryption: Removing Private-Key Generator from IBE

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    In this work, we introduce the notion of registration-based encryption (RBE for short) with the goal of removing the trust parties need to place in the private-key generator in an IBE scheme. In an RBE scheme, users sample their own public and secret keys. There will also be a ``key curator\u27\u27 whose job is only to aggregate the public keys of all the registered users and update the short public parameter whenever a new user joins the system. Encryption can still be performed to a particular ecipient using the recipient\u27s identity and any public parameters released subsequent to the recipient\u27s registration. Decryption requires some auxiliary information connecting users\u27 public (and secret) keys to the public parameters. Because of this, as the public parameters get updated, a decryptor may need to obtain a few additional auxiliary information for decryption. More formally, if nn is the total number of identities and Îș\kappa is the security parameter, we require the following. Efficiency requirements: (1) A decryptor only needs to obtain updated auxiliary information for decryption at most O(log⁥n)O(\log n) times in its lifetime, (2) each of these updates are computed by the key curator in time poly(Îș,log⁥n)poly(\kappa,\log n), and (3) the key curator updates the public parameter upon the registration of a new party in time poly(Îș,log⁥n)poly(\kappa,\log n). Properties (2) and (3) require the key curator to have \emph{random} access to its data. Compactness requirements: (1) Public parameters are always at most poly(Îș,log⁥n)poly(\kappa,\log n) bit, and (2) the total size of updates a user ever needs for decryption is also at most poly(Îș,log⁥n)poly(\kappa,\log n) bits. We present feasibility results for constructions of RBE based on indistinguishably obfuscation. We further provide constructions of \emph{weakly efficient} RBE, in which the registration step is done in poly(Îș,n)poly(\kappa, n), based on CDH, Factoring or LWE assumptions. Note that registration is done only once per identity, and the more frequent operation of generating updates for a user, which can happen more times, still runs in time poly(Îș,log⁥n)poly(\kappa,\log n). We leave open the problem of obtaining standard RBE (with poly(Îș,log⁥n)poly(\kappa,\log n) registration time) from standard assumptions

    Reproductive morbidity among Iranian women; issues often inappropriately addressed in health seeking behaviors

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    <p>Abstract</p> <p>Background</p> <p>Reproductive morbidity has a huge impact on the health and quality of life of women. We aimed to determine the prevalence of reproductive morbidities and the health seeking behavior of a nationally representative sample of Iranian urban women.</p> <p>Methods</p> <p>A sample of 1252 women, aged 18-45 years, was selected using the multi stage, stratified probability sampling procedure. Data were collected through interviews and physical, gynecological and ultrasonographic examinations.</p> <p>Results</p> <p>Reproductive tract infection (RTIs), pelvic organ prolapse (POP) and menstrual dysfunction were the three main groups of morbidities with a prevalence of 37.6%, 41.4% and 30.1%., respectively. Our study demonstrated that 35.1, 34.5 and 9.6 percent of women experienced one, two or these reproductive organ disorders mentioned, respectively, while 20.6 percent of participants had none of these disorders. Findings also showed that the majority of women who suffered from reproductive morbidities (on average two out of three) had not sought appropriate care for these except for infertility.</p> <p>Conclusions</p> <p>Reproductive health morbidities impose a large burden among Iranian women and have negative impact on their reproductive health and wellbeing.</p

    Estimating the prevalence of obstetric fistula: a systematic review and meta-analysis.

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    BACKGROUND: Obstetric fistula is a severe condition which has devastating consequences for a woman's life. The estimation of the burden of fistula at the population level has been impaired by the rarity of diagnosis and the lack of rigorous studies. This study was conducted to determine the prevalence and incidence of fistula in low and middle income countries. METHODS: Six databases were searched, involving two separate searches: one on fistula specifically and one on broader maternal and reproductive morbidities. Studies including estimates of incidence and prevalence of fistula at the population level were included. We conducted meta-analyses of prevalence of fistula among women of reproductive age and the incidence of fistula among recently pregnant women. RESULTS: Nineteen studies were included in this review. The pooled prevalence in population-based studies was 0.29 (95% CI 0.00, 1.07) fistula per 1000 women of reproductive age in all regions. Separated by region we found 1.57 (95% CI 1.16, 2.06) in sub Saharan Africa and South Asia, 1.60 (95% CI 1.16, 2.10) per 1000 women of reproductive age in sub Saharan Africa and 1.20 (95% CI 0.10, 3.54) per 1000 in South Asia. The pooled incidence was 0.09 (95% CI 0.01, 0.25) per 1000 recently pregnant women. CONCLUSIONS: Our study is the most comprehensive study of the burden of fistula to date. Our findings suggest that the prevalence of fistula is lower than previously reported. The low burden of fistula should not detract from their public health importance, however, given the preventability of the condition, and the devastating consequences of fistula
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