Evolution of a localized thermal explosion in a reactive gas

Experimental observations of ignition in premixed gaseous reactants indicate that perfectly homogeneous initiation is practically unrealizable. Instead, combustion first sets in, as a rule, at small, discrete sites where inherent inhomogeneities cause chemical activity to proceed preferentially and lead to localized explosions. Combustion waves propagating away from these hot spots or reaction centers eventually envelop the remaining bulk. This study examines the spatial structure and temporal evolution of a hot spot for a model involving Arrhenius kinetics. The hot spot, characterized by peaks in pressure and temperature with little diminution in local density, is shown to have one of two possible self-similar structures. The analysis employs a combination of asymptotics and numerics, and terminates when pressure and temperature in the explosion have peaked

Ignition of thermally sensitive explosives between a contact surface and a shock

The dynamics of ignition between a contact surface and a shock wave is investigated using a one-step reaction model with Arrhenius kinetics. Both large activation energy asymptotics and high-resolution finite activation energy numerical simulations are employed. Emphasis is on comparing and contrasting the solutions with those of the ignition process between a piston and a shock, considered previously. The large activation energy asymptotic solutions are found to be qualitatively different from the piston driven shock case, in that thermal runaway first occurs ahead of the contact surface, and both forward and backward moving reaction waves emerge. These waves take the form of quasi-steady weak detonations that may later transition into strong detonation waves. For the finite activation energies considered in the numerical simulations, the results are qualitatively different to the asymptotic predictions in that no backward weak detonation wave forms, and there is only a weak dependence of the evolutionary events on the acoustic impedance of the contact surface. The above conclusions are relevant to gas phase equation of state models. However, when a large polytropic index more representative of condensed phase explosives is used, the large activation energy asymptotic and finite activation energy numerical results are found to be in quantitative agreement

Evaluation of juxta-apical radiolucency in cone beam CT images

OBJECTIVES: The aim of this study was to analyse the position and relationship of juxta-apical radiolucency (JAR) to the mandibular canal and buccal and/or lingual cortical plates using cone beam CT (CBCT). METHODS: A retrospective study was carried out to analyse the JAR on CBCT for 27 patients. These findings were compared with 27 age- and sex-matched patients without the presence of JAR, which acted as the control group. The CBCT images were analysed according to a checklist, to evaluate the position of the JAR and its relationship to the mandibular canal. Then, any thinning or perforation of either the buccal or lingual cortical plate due to JAR was noted, and a classification to quantify the thinning of cortical plates was proposed. The findings in the two groups were analysed using a paired comparison by McNemar test. RESULTS: A statistical increased thinning of cortical plates was seen in the JAR group compared with the control group, and most of the cases were in the J3 group. None of the patients in either the JAR or the control group showed perforation of the buccal and/or lingual cortical plate on CBCT images. CONCLUSIONS: A classification to quantify the thinning of cortical plates was proposed, which may be used for objective evaluation of the thinning of the cortical plates in future studies. The present study gives an insight into the relationship of the juxta-apical area with the mandibular canal and cortical plates in the mandible using CBCT.published_or_final_versio

Reactive-diffuse System with Arrhenius Kinetics: Peculiarities of the Spherical Goemetry

The steady reactive-diffusive problem for a non isothermal permeable pellet with first-order Arrhenius kinetics is studied. In the large activation-energy limit, asymptotic solutions are derived for the spherical geometry. The solutions exhibit multiplicity and it is shown that a suitable choice of parameters can lead to an arbitrarily large number of solutions, thereby confirming a conjecture based upon past computational experiments. Explicit analytical expressions are given for the multiplicity bounds (ignition and extinction limits). The asymptotic results compare very well with those obtained numerically, even for moderate values of the activation energy

Bis(di-n-butoxyphosphato) cobalt (II) & Its Complexes with Lewis Bases

500-50

Expression and Characterization of Chandipura Virus Proteins

Chandipura virus (CHPV) has recently emerged as an extremely lethal human pathogen in the family Rhabdoviridae and is linked to significant encephalitis outbreaks in different parts of India. The biology of CHPV remains less studied to date and the availability of reagents such as purified proteins can enhance research in this direction. In this study, we have overexpressed four of the CHPV proteins namely Nucleoprotein (N), Phosphoprotein (P), Matrix protein (M) and Glycoprotein (G) using three  distinct tags in bacterial system and with changes in inducer concentration, growth and solubilisation conditions successfully purified M and G proteins for the first time along with N and P. Furthermore, the interactions of CHPV M protein with other viral proteins (G, N and P) was investigated using ELISA and GST pull down assays to show the utility of olubilised proteins. The results of both the assays demonstrated that M protein interacts with both G and N proteins, while it does not interact with P protein, in a similar  manner as reported for Vesicular Stomatitis Virus

Interpreting a Diagnosis of Atypical Squamous Cells of Undetermined Significance in Cervical Cytology and its Association with Human Papillomavirus: A retrospective analysis of 180 cases in Kuwait

Objectives: Atypical squamous cells of undetermined significance (ASC-US) represent a diagnostic challenge during cervical cytology. This study aimed to review and identify high-risk human papillomavirus (HR-HPV) genotypes among previously diagnosed ASC-US cases in Kuwait. Methods: This retrospective study analysed 180 cases diagnosed as ASC-US between June 2017 and May 2018 at the Mubarak Al-Kabeer Hospital, Kuwait. Cervical specimens were assayed to determine the presence of HR-HPV DNA; subsequently, positive cases underwent genotyping and were categorised into three groups (HPV 16, HPV 18/45 and other HR-HPV types). Results: In total, ASC-US was confirmed in only 105 cases (58.3%), with the remaining cases reclassified as negative for intraepithelial lesions or malignancy (NILM; 32.2%) and epithelial cell abnormalities (ECA; 9.4%). Of these, HRHPV DNA was present in 20 ASC-US (19%), one NILM (1.7%) and six ECA (35.3%) cases. There were 62 Kuwaiti and 43 non-Kuwaiti women with confirmed ASC-US; of these, three (4.8%), six (9.7%) and four (6.5%) Kuwaitis and one (2.3%), one (2.3%) and five (11.6%) non-Kuwaitis had HPV 16, both HPV 16 and 18/45 and other HRHPV genotypes, respectively. Of those with HR-HPV DNA, the NILM case had the HPV 18/45 genotype, while the six ECA cases had the HPV 16 (n = 1), both HPV 16 and 18/45 (n = 1) and other HR-HPV (n = 4) genotypes. Conclusion: Overall, HR-HPV DNA was present in 19% of ASC-US cases compared to 1.7% of NILM cases initially misdiagnosed as ASC-US. Re-review of cervical cytology diagnoses may reduce unnecessary costs associated with HR-HPV genotyping. Keywords: Cervical Smears; Atypical Squamous Cells of Undetermined Significance; Human Papilloma Virus; Cytological Techniques; Papanicolaou Test; Kuwait

Evaluation of formulated diets with different levels of marine protein mixtures in aquariculture of koi carp Cyprinus carpio var. koi (Linnaeus, 1758)

A marine protein mixture of fish, squid, shrimp and clam meal in equal proportion was incorporated at different levels in the diets formulated and designated as P16, P19, P26, P33, P40, P47, P53 and P59 for koi carp. Triplicate groups of 10 fish each were fed with the experimental diets for 12 weeks and assessed for growth and body composition. On physical evaluation of the extruded feeds, above 80% dry matter retention for 4 h was evident in feeds P26 to P47. Feeds with more starch (wheat) P19 and P16 had stability of more than 90% and feeds with less starch, P53 and P59 had a stability of less than 70%. The body tissue of the experimental animals fed with P59 and P53 had significantly (p<0.05) high levels of polyunsaturated fatty acids (PUFA). Total ash in the body decreased with proportionate decrease in nutrient density. Biomass gain was similar with feeds P33, P40, P47 and P53. Growth as a function of incremental levels of marine protein mixtures in diet was linear. Diets containing 250, 300 and 350 g kg-1 protein is advocated for normal growth and 400 to 450 g kg-1 protein mixture are recommended to promote faster growth

Evaluation of pulmonary infiltrates in patients with haematological malignancies using fibreoptic bronchoscopy and bronchoalveolar lavage

Background : Chest infection is the major cause of morbidity and mortality among patients with haematological malignancies. Conventional diagnostic methods - chest x-ray , blood and sputum culture have limited yield . We used fibreoptic bronchoscopy and bronchoalveolar lavage to evaluate nature of pulmonary infiltrates on chest x-ray. Patients and Methods : 25 patients with haematological malignancies with fever and pulmonary infiltrates were studied. Patients median age was 32 years, ranging from 16 to 65 years. There were 21 males and 4 females. Initial evaluation included - detailed physical examination including chest to see for any focus of infection. In all patients , base line blood counts (total and differential), chest x-ray and cultures from blood and other body fluids were taken before starting broad spectrum antibiotics . Those not responding over next 48-72 hours received gram positive coverage followed by amphotericin-B therapy . Patients with persistent fever and pulmonary infiltrates were subjected to fibre-optic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) and samples were collected for bacterial, fungal, AFB and viral studies. The findings were correlated with Chest x-ray and CT scan. Results The median time for FOB and BAL was 16 days (range, 3 to 32 days) after the clinical diagnosis of chest infection.. BAL fluid examination/culture grew microbial isolates in 21 of 25 patients (84%). Of thesebacteria alone were present in 10, fungi alone in 1 and polymicrobial isolates were seen in 10 patients (40%). Later included- a combination of bacteria and fungi - in 2 patients, bacteria and AFB - 6 and a combination of bacteria, AFB and fungi were seen in 2 patients. BAL changed the radiological diagnosis in 14 patients (56% diagnostic utility). Therapy was modified according to BAL results in 6 patients (therapeutic utility of 24 %). Concordance between radiological and BAL findings were found only in 5 patients (20%). FOB procedure was tolerated well, with mild and reversible complications (throat pain, transient hypoxia, tachycardia) in some patients. Conclusions: Infections are the main cause of pulmonary infiltrates in patients with haematological malignancies. Bacterial , fungal and mycobacterium tubercular organisms are the main isolates. Isolation of ESBL positive organisms and polymicrobial isolates suggest inclusion of appropriate initial empirical antibiotics in these patients to prevent development of resistant organisms. Higher frequency of AFB isolates (32%) was the surprising finding and need to be confirmed in future studies