Machinability Investigation of Nitronic 60 Steel Turning Using SiAlON Ceramic Tools under Different Cooling/Lubrication Conditions

The machining of nickel-based super alloys is challenging, owing to the generation of high cutting temperatures, as well as difficulty in maintaining dimensional accuracy and minimizing surface roughness, which compels the use of cutting fluids for reducing these issues due to efficient cooling/lubrication strategies. The present work investigates the comparative performance of four cooling/lubrication techniques: dry cutting, wet, minimum quantity lubricant (MQL) and compressed-air modes in turning Nitronic 60 steel using a new-generation SiAlON ceramic inserts. Several machinability parameters were analyzed for performance evaluation. For this purpose, 16 cycles of turning trials were performed based on Taguchi’s L₁₆ orthogonal array experimental design by varying cutting conditions and lubrication modes. MQL exhibits beneficial effects as compared to the other lubrication conditions concerning low cutting force, improved surface finish, decreased cutting temperature, longer tool life, and lower white layer thickness on machined surface. Burr formation on the saw-tooth chip surface, as well as friction, greatly influenced the tool flank wear due to improper cooling and poor lubrication approach in dry, wet, and compressed-air-cooled machining environments in comparison to MQL-machining. From an economical perspective, the tool life in MQL machining improved by 11%, 72%, and 138% in the comparison with flooded, compressed-air, and dry conditions, respectively. The results of the study demonstrate that using the MQL system can help with heat extraction capability, and provide some promising outcomes.     

Quantifying disease progression in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) exhibits characteristic variability of onset and rate of disease progression, with inherent clinical heterogeneity making disease quantitation difficult. Recent advances in understanding pathogenic mechanisms linked to the development of ALS impose an increasing need to develop strategies to predict and more objectively measure disease progression. This review explores phenotypic and genetic determinants of disease progression in ALS, and examines established and evolving biomarkers that may contribute to robust measurement in longitudinal clinical studies. With targeted neuroprotective strategies on the horizon, developing efficiencies in clinical trial design may facilitate timely entry of novel treatments into the clinic. Ann Neurol 2014;76:643–657     

Intranasal sumatriptan for acute migraine attacks: a systematic review and meta-analysis

We performed this systematic review and meta-analysis to evaluate the tolerability and efficacy of intranasal sumatriptan, a selective serotonin agonist, compared to placebo or other migraine therapeutics for the treatment of acute migraine attacks. We searched PubMed, SCOPUS, Embase, and Cochrane CENTRAL for relevant randomized controlled trials (RCTs). Data were extracted from eligible studies and pooled as risk ratios (RR), using RevMan software. We performed subgroup and meta-regression analyses for different doses and treatment endpoints. Sixteen RCTs (n = 5925 patients) matched our inclusion criteria. The overall effect-estimate showed that intranasal sumatriptan was superior to placebo in terms of pain relief (RR = 1.70, 95% CI [1.31, 2.21], p < 0.0001) and headache relief (RR = 1.58, 95% CI [1.35, 1.84], p < 0.00001) at 2 h. Although sumatriptan was superior to placebo in terms of headache relief at 30 min (RR = 1.31, 95% CI [1.08, 1.59], p = 0.005), no significant difference was found between both groups in terms of the frequency of pain-free participants at 30 min (RR = 1.18, 95% CI [0.49, 2.88], p = 0.71). Subgroup analysis and meta-regression models showed that increasing the dose of sumatriptan reduced the time needed for headache relief; however, this clinical improvement with higher doses was associated with more frequent adverse events in comparison to smaller doses. In conclusion, intranasal sumatriptan is effective for the treatment of acute migraine attacks. However, it was associated with a six-fold increase in the risk of taste disturbance, compared to the placebo. Future RCTs are recommended to provide head-to-head comparison of different administration routes and drug formulations of sumatriptan.     

A neurotropic route for Maize mosaic virus (Rhabdoviridae) in its planthopper vector Peregrinus maidis

To investigate the dissemination route of Maize mosaic virus (MMV, Rhabdoviridae) in its planthopper vector Peregrinus maidis (Delphacidae, Hemiptera), temporal and spatial distribution of MMV was studied by immunofluorescence confocal laser scanning microscopy following 1-week acquisition feeding of planthoppers on infected plants. MMV was detected 1-week post first access to diseased plants (padp) in the midgut and anterior diverticulum, 2-week padp in the esophagus, nerves, nerve ganglia and visceral muscles, and 3-week padp in hemocytes, tracheae, salivary glands and other tissues. MMV is neurotropic in P. maidis; infection was more extensive in the nervous system compared to other tissues. A significantly higher proportion of planthoppers had infected midguts (28.1%) compared to those with infected salivary glands (20.4%) or to those that transmitted MMV (15.7%), suggesting the occurrence of midgut and salivary gland barriers to MMV transmission in P. maidis. In this planthopper, the esophagus and anterior diverticulum are located between the compound ganglionic mass and the salivary glands. We postulate that MMV may overcome transmission barriers in P. maidis by proceeding from the midgut to the anterior diverticulum and esophagus, and from these to the salivary glands via the nervous system: a neurotropic route similar to that of some vertebrate-infecting rhabdoviruses.     

Novel prokaryotic diversity in sediments of Tunisian multipond solar saltern

The phylogenetic diversity of a sediment microbial community from two ponds having different salinities, 150–200 g/l (M2) and 250–300 g/l (TS38), of an Sfax (Tunisia) solar saltern, was investigated using 16S rRNA clone libraries. The 16S rRNA genes from 135 bacterial clones and 105 archaeal clones were sequenced and phylogenetically analyzed. 32 operational taxonomic units (OTUs) were generated for Bacteria and 64 for Archaea. The bacterial community in M2 sediment was affiliated only with Bacteroidetes, while that in TS38 sediment was dominated by clones affiliated with Bacteroidetes, (gamma, alpha, delta) Proteobacteria and unclassified bacteria; these represented 56.52, 26.08, 4.34, 4.34 and 8.7% of the OTUs, respectively. In the M2 and TS38 sediments, 44.44 and 43.47% of the bacterial OTUs, respectively, were novel. All archaeal sequences fell into the Euryarchaeota phylum. In both sediments, 38.46 and 72.55% of the OTUs had less than 97% 16S rRNA sequence identity, representing novel OTUs. Two sequences, retrieved from TS38 sediment, were found to be affiliated with the candidate division MSBL-1 defining two OTUs. The sediment phylogenetic study revealed the presence of a highly diverse microbial population in highly salty media.     

Anxiolytic-like effects of mitragynine in the open-field and elevated plus-maze tests in rats

The effects of mitragynine on anxiety-related behaviours in the open-field and elevated plus-maze tests were evaluated. Male Sprague–Dawley rats were orally treated with mitragynine (10, 20 and 40 mg/kg) or diazepam (10 mg/kg) 60 min before behavioural testing. Mitragynine doses used in this study were selected on the basis of approximately human equivalent doses with reference to our previous literature reports. Acute administration of mitragynine (10, 20 and 40 mg/kg) or diazepam (10 mg/kg) increased central zone and open arms exploration in the open-field and elevated plus-maze tests respectively. These anxiolytic-like effects of mitragynine were effectively antagonized by intraperitoneal administration of naloxone (2 mg/kg), flumazenil (10 mg/kg), sulpiride (0.5 mg/kg) or SCH 23390 (0.02 mg/kg) 15 min before mitragynine treatments. These findings reveal that the acute administration of mitragynine produces anxiolytic-like effects and this could be possibly attributed to the interactions among opioidergic, GABAergic and dopaminergic systems in brain regions involved in anxiety.     

Inflammatory pseudotumor of the spleen: two case reports

Inflammatory pseudotumor (IPT) of the spleen is an uncommon entity with debated etiology, characterized by a mixture of inflammatory cells and a component of myofibroblastic spindle cells. This lesion needs to be distinguished from the follicular dendritic cell tumor and the inflammatory myofibroblastic tumor. We report two cases of splenic PTI in a 69-year old and a 62-year old women. The tumors measured respectively 80 and 30 mn in greatest dimension. An inflammatory pseudotumor was histopathologically diagnosed following a splenectomy.