Magnetic Field Structure and Stochastic Reconnection in a Partially Ionized Gas

We consider stochastic reconnection in a magnetized, partially ionized medium. Stochastic reconnection is a generic effect, due to field line wandering, in which the speed of reconnection is determined by the ability of ejected plasma to diffuse away from the current sheet along magnetic field lines, rather than by the details of current sheet structure. We consider the limit of weak stochasticity, so that the mean magnetic field energy density is greater than either the turbulent kinetic energy density or the energy density associated with the fluctuating component of the field. We consider field line stochasticity generated through a turbulent cascade, which leads us to consider the effect of neutral drag on the turbulent cascade of energy. In a collisionless plasma, neutral particle viscosity and ion-neutral drag will damp mid-scale turbulent motions, but the power spectrum of the magnetic perturbations extends below the viscous cutoff scale. We give a simple physical picture of the magnetic field structure below this cutoff, consistent with numerical experiments. We provide arguments for the reemergence of the turbulent cascade well below the viscous cut-off scale and derive estimates for field line diffusion on all scales. We note that this explains the persistence of a single power law form for the turbulent power spectrum of the interstellar medium, from scales of tens of parsecs down to thousands of kilometers. We find that under typical conditions in the ISM stochastic reconnection speeds are reduced by the presence of neutrals, but by no more than an order of magnitude.Comment: Astrophysical Journal in pres

A clinical study of displaced clavicle fractures treated with precontoured locking compression plate

Background: Fractures which involve the clavicle are very common and account for almost 5-10% of all the fractures and up to around 45% of those which involve the shoulder girdle. Most of these fractures occur due to a direct blow to the anterior chest wall or by falling on the outstretched hand. Traditionally, clavicular fractures have been treated with conservative methods, but the outcome was poor, leading to patient dissatisfaction. An option is the precontoured locking plates which provide immediate relief, stabilization and early mobilization, more so because they do not require further bending.Methods: 50 patients, above 18 years of age, with closed displaced clavicular fractures were included in the study. Clinical evaluation was done for all the patients using the Constant-Murley score. Precontoured locking compression plate was inserted surgically for the treatment of the fracture and follow-up was done for 6 months postoperatively.Results: Out of the 50 patients studied, 42 were males (84%) and 8 (16%) were females. Most of the patients belonged to 21-50 years of the age group. Road traffic accidents were the most common cause (98%) for this type of fractures. Most of the fractures were united by 11-12 weeks of duration (42%), closely followed by a time period of 9-10 weeks (40%). Most of the patients showed full range of movement (84%), while 6% showed movements which were restricted by 200 and 10% showed 300 restrictions. In 32% of the cases, the outcome was excellent while only 6% of the patients showed a fair outcome. Conclusions: Displaced mid-shaft clavicle fractures treated with precontoured locking compression plates gave good functional outcome and patient satisfaction with excellent reunion rates

Case studies to enhance online student evaluation: Bond University – Surveying students online to improve learning and teaching

One of the most sensible ways of improving learning and teaching is to ask the students for feedback. At the end of each teaching period (i.e. semester or term) all universities and many schools survey their students. Usually these surveys are managed online. Questions ask for student perceptions about teaching, assessment and workload. The survey administrators report four common problems

Inhibitory properties of ibuprofen and its amide analogues towards the hydrolysis and cyclooxygenation of the endocannabinoid anandamide

A dual-action cyclooxygenase (COX)–fatty acid amide hydrolase (FAAH) inhibitor may have therapeutic usefulness as an analgesic, but a key issue is finding the right balance of inhibitory effects. This can be done by the design of compounds exhibiting different FAAH/COX-inhibitory potencies. In the present study, eight ibuprofen analogues were investigated. Ibuprofen (1), 2-(4-Isobutylphenyl)-N-(2-(3-methylpyridin-2-ylamino)-2-oxoethyl)propanamide (9) and N-(3-methylpyridin-2-yl)-2-(4′-isobutylphenyl)propionamide (2) inhibited FAAH with IC50 values of 134, 3.6 and 0.52 µM respectively. The corresponding values for COX-1 were ~29, ~50 and ~60 µM, respectively. Using arachidonic acid as substrate, the compounds were weak inhibitors of COX-2. However, when anandamide was used as COX-2 substrate, potency increased, with approximate IC50 values of ~6, ~10 and ~19 µM, respectively. Compound 2 was confirmed to be active in vivo in a murine model of visceral nociception, but the effects of the compound were not blocked by CB receptor antagonists. Read More: http://informahealthcare.com/doi/abs/10.3109/14756366.2011.64330

Golgi Associated HIF1a Serves as a Reserve in Melanoma Cells

Hypoxia-inducible factor-1alpha (HIF1a) is a key transcriptional regulator that enables cellular metabolic adaptation to low levels of oxygen. Multiple mechanisms, including lysosomal degradation, control the levels of HIF1a protein. Here we show that HIF1a protein degradation is resistant to lysosomal inhibition and that HIF1a is associated with the Golgi compartment in melanoma cells. Although pharmacological inhibitors of prolyl hydroxylation, neddylation and the proteasome inhibited degradation of HIF1a, attenuation of lysosomal activity with chloroquine did not alter the levels of HIF1a or its association with Golgi. Pharmacological disruption of Golgi resulted in nuclear accumulation of HIF1a. However, blockade of ER-Golgi protein transport in hypoxia reduced the transcript levels of HIF1a target genes. These findings suggest a possible role for the oxygen-dependent protein folding process from the ER-Golgi compartment in fine-tuning HIF1a transcriptional output

On the organic carbon maximum on the continental slope of the eastern Arabian Sea

The sedimentary organic carbon maximum on the continental slope off western India is widely believed to be due to the preferential preservation of deposited organic matter at water depths where the intense oxygen minimum intersects the sea floor. This region is considered to constitute one of the modern analogues for the environment of formation of organic-rich sedimentary facies that are common in the geological record. We critically examine the hypothesis that the oxygen minimum in the eastern Arabian Sea is the site of enhanced organic matter accumulation and preservation using analyses of suites of samples with wide geographical coverage along this margin. Organic carbon and nitrogen reach maximum concentrations between 200 and 1600 m depth, whereas the lowest dissolved oxygen contents in the oxygen minimum lie between 200 and 800 m depth. The Corganic/N ratios and the δ13Corganic values show that the organic matter is overwhelmingly marine, and Rock-Eval pyrolysis data demonstrate that the hydrogen indices of the sediments are similar in the sediments accumulating within and outside the oxygen minimum. Thus, the organic carbon maximum extends over a larger depth range than the oxygen minimum (as is also evident on some other slopes), and there is no evidence for preferential preservation of the organic matter within the oxygen minimum. The distribution of organic matter on the western Indian continental margin is controlled by (1) variations in supply (decreasing westward away from the centers of coastal upwelling and also decreasing with increasing water depth), (2) dilution by other sedimentary components, and (3) the texture of the sediments (coarser-grained sediments having lower carbon contents), which is controlled in turn by sediment supply and reworking. The evidence available suggests that the organic carbon maximum on this slope is not related to the position of the oxygen minimum and, consequently, that oxygen minima cannot be used to explain the distribution of organic carbon at intermediate palaeodepths in the geological record

Correlation between malondialdehyde (MDA) and uric acid levels in preeclampsia

Background: Hypertensive disorders of human pregnancy, such as preeclampsia, complicates a sizeable percentage of all pregnancies, need its early indication and warning. The aim of present study was to determine the association between lipid peroxidation product, serum malondialdehyde (MDA) and serum uric acid levels in preeclampsia and find out any association between these two parameters in preeclampsia. Methods: Thirty preeclampsia and thirty gestational age matched normotensive pregnant women attending Narayana General Hospital, Nellore were included in the study. Serum MDA levels were measured by Thiobarbituric acid reactive substances(TBARS) method and serum uric acid levels were estimated by automated chemistry analyser using commercial kits. Results: Serum MDA (Mean±SEM 24.4±2.38 vs 7.9± 0.28 nmol/ml, p value < 0.000) and serum uric acid levels (7.2 ± 0.25 vs 3.9 ± 0.14 mg/dl, p value <0.000) were significantly elevated in preeclampsia cases when compared with that of normotensive pregnant women. A weak positive correlation between serum uric acid and serum MDA (r value 0.065, p value 0.734) was noticed in preeclampsia.Conclusion: Serum MDA and uric acid may be included as additional markers for screening and progression of preeclampsia, thereby helpful in effectively treating the condition at an early stage.

Performance of titanium salts compared to conventional FeCl<inf>3</inf> for the removal of algal organic matter (AOM) in synthetic seawater: Coagulation performance, organic fraction removal and floc characteristics

© 2017 Elsevier Ltd During algal bloom periods, operation of seawater reverse osmosis (SWRO) pretreatment processes (e.g. ultrafiltration (UF)) has been hindered due to the high concentration of algal cells and algal organic matter (AOM). The present study evaluated for the first time the performance of titanium salts (i.e. titanium tetrachloride (TiCl4) and polytitanium tetrachloride (PTC)) for the removal of AOM in seawater and results were compared with the conventional FeCl3 coagulant. Previous studies already demonstrated that titanium salts not only provide a cost-effective alternative to conventional coagulants by producing a valuable by-product but also minimise the environmental impact of sludge production. Results from this study showed that both TiCl4 and PTC achieved better performance than FeCl3 in terms of turbidity, UV254 and dissolved organic carbon (DOC) removal at similar coagulant dose. Liquid chromatography – organic carbon detection (LC-OCD) was used to determine the removal of AOM compounds based on their molecular weight (MW). This investigation revealed that both humic substances and low MW organics were preferentially removed (i.e. up to 93% removal) while all three coagulants showed poorer performance for the removal of high MW biopolymers (i.e. less than 50% removal). The detailed characterization of flocs indicated that both titanium coagulants can grow faster, reach larger size and present a more compact structure, which is highly advantageous for the design of smaller and more compact mixing and sedimentation tanks. Both titanium coagulants also presented a higher ability to withstand shear force, which was related to the higher amount of DOC adsorbed with the aggregated flocs. Finally, TiCl4 had a better recovery after breakage suggesting that charge neutralization may be the dominant mechanism for this coagulant, while the lower recovery of both PTC and FeCl3 indicated that sweep flocculation is also a contributing mechanism for the coagulation of AOM