A formulation for calculating the translational velocity of a vortex ring or pair

Cephalopods, among other marine animals, use jet propulsion for swimming. A simple actuator is designed to loosely mimic pulsatile jet formation in squid and jellyfish. The actuator is comprised of a cavity with an oscillating diaphragm and an exit orifice. Periodic oscillation of the diaphragm results in the formation of an array of vortex rings and eventually could generate a periodic pulsatile jet. A general formulation for calculating the velocity of a steadily translating vortical structure in two-dimensional and axi-symmetric shear flows is presented. This technique is based on taking the variational derivative of an energetic function at its critical point. This technique is general, applicable to vortices in liquid and gas media, with no limitation on the relative size of the vortex core. The technique is then implemented to estimate the translational velocity of a vortex ring in a Helmholtz vortex ring generator.     

Lessons from peroxisome-deficient Chinese hamster ovary (CHO) cell mutants

Cells with a genetic defect affecting a biological activity and/or a cell phenotype are generally called "cell mutants" and are a highly useful tool in genetic, biochemical, as well as cell biological research. To investigate peroxisome biogenesis and human peroxisome biogenesis disorders, more than a dozen complementation groups of Chinese hamster ovary (CHO) cell mutants defective in peroxisome assembly have been successfully isolated and established as a model system. Moreover, successful PEX gene cloning studies by taking advantage of rapid functional complementation assay of CHO cell mutants invaluably contributed to the accomplishment of isolation of pathogenic genes responsible for peroxisome biogenesis diseases. Molecular mechanisms of peroxisome assembly are currently investigated by making use of such mammalian cell mutants.     

Gastric xanthoma: a diagnostic problem on brushing cytology smears

OBJECTIVE: To describe the cytologic findings of gastric xanthomas and to compare them with the findings of signet-ring adenocarcinoma because atypical xanthoma cells can be easily confused with signet-ring adenocarcinoma cells. STUDY DESIGN: Five cases of gastric xanthoma that were confirmed by biopsy reports were selected for study. The patients' ages ranged between 50 and 58 years; 4 were men and 1 was a woman. Twenty-one cases of signet-ring adenocarcinoma confirmed by biopsy reports were selected for comparison. Special staining was performed. RESULTS: The brushing cytology smears of the 5 cases of xanthoma revealed atypical cells, so initially they were reported as suspicious for signet-ring adenocarcinoma and biopsy examination advised. After learning of the histologic diagnosis of xanthoma, we performed special staining. The xanthoma cells were negative with periodic acid-Schiff (PAS) stain but showed a positive reaction with Oil red 0 and weakly positive reaction with Masson trichrome. Signet-ring adenocarcinoma cells showed a strongly positive reaction with PAS stain. CONCLUSION: Gastric brushing cytology findings of xanthomas have not been described before. At times the differentiation of atypical xanthoma cells from signet-ring adenocarcinoma cells is very difficult on brushing cytology smears. In this study the nuclear changes and special stains helped differentiate the 2 lesions.     

Detection of gender differences in rat lens proteins using 2-D-DIGE

The glass-like transparency of the human eye lens is achieved by the tight packing of abundant crystallin proteins. However, the precise role of the accessory non-crystallin proteins is not well understood. We have carried out 2-DE mapping of these proteins in rat lens. This showed the presence of the high molecular weight filamentous structural proteins spectrin, filensin, tubulin, vimentin, actin and phakinin as well as several forms of potential crystallin oligomers comprised of alphaA, betaB1, betaA1 and betaA4 chains. Other proteins that were present include, heat shock protein 71, WD repeat protein 1, and several enzymes including alpha-enolase, pyruvate kinase, transketolase and aldose reductase. 2-D-DIGE analysis revealed several expression differences between the lens proteomes of male and female rats. Female rat lenses contained lower levels of aldose reductase, increased proteolyic fragments of the structural proteins filensin, vimentin and phakinin and higher levels of potential alphaA, betaB1 and betaA1 crystallin oligomers. Taken together these findings suggest that there are potential differences in oxidative stress regulation between male and female rat lenses, which may have implications on susceptibility to cataract formation. Future studies aimed at elucidating pre-cataractic changes in the non-crystallin proteins described here may facilitate identification of novel markers involved in cataractogenesis.     

Disease forecasting model for newly emerging bacterial seed and boll rot of cotton disease and its vector (Dysdercus cingulatus)

Bacterial seed and boll rot disease is a newly emerging threat to the cotton growers. Disease prediction model was devised to predict the disease progression impacted by the vector (Dysdercus cingulatus) and environmental variables (maximum air temperature, minimum air temperature, relative humidity and rainfall) on four varieties to minimise its losses and disease management cost. Impact of a-biotic environmental variables (maximum and minimum air temperature, relative humidity and rainfall) was assessed on bacterial seed and rot of cotton disease and its vector (D. cingulatus) on FH-941, FH-942, MNH-886 and FH-114 cotton varieties. Maximum red cotton bug population was assessed at 29–31 °C maximum temperature and at 15–17 °C minimum temperature. Disease severity was noticed maximum when maximum and minimum temperature was measured at 28–29 °C and 13–14.5 °C, respectively. Vector population was maximum when relative humidity and rainfall were 63–66% and 1.50–2.5 mm, respectively. Relative humidity at 66–68% and 0.5–1.5 mm rainfall favoured disease development. With increase in number of bugs, increase in disease severity was noted, maximum disease severity 45–48% noticed when 7–8 bugs were recorded. Red cotton bug (Dysdercus cingulatus) population prediction model was devised based on a-biotic factors (maximum and minimum air temperature, relative humidity and rainfall) on four cotton varieties. Disease forecasting model was developed based on biotic (D. cingulatus) and a-biotic factors. A close resemblance between observed and the predicted red cotton bugs and disease severity was seen.     

Four novel Loci (19q13, 6q24, 12q24, and 5q14) influence the microcirculation in vivo

There is increasing evidence that the microcirculation plays an important role in the pathogenesis of cardiovascular diseases. Changes in retinal vascular caliber reflect early microvascular disease and predict incident cardiovascular events. We performed a genome-wide association study to identify genetic variants associated with retinal vascular caliber. We analyzed data from four population-based discovery cohorts with 15,358 unrelated Caucasian individuals, who are members of the Cohort for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium, and replicated findings in four independent Caucasian cohorts (n = 6,652). All participants had retinal photography and retinal arteriolar and venular caliber measured from computer software. In the discovery cohorts, 179 single nucleotide polymorphisms (SNP) spread across five loci were significantly associated (p<5.0×10(-8)) with retinal venular caliber, but none showed association with arteriolar caliber. Collectively, these five loci explain 1.0%-3.2% of the variation in retinal venular caliber. Four out of these five loci were confirmed in independent replication samples. In the combined analyses, the top SNPs at each locus were: rs2287921 (19q13; p = 1.61×10(-25), within the RASIP1 locus), rs225717 (6q24; p?=?1.25×10(-16), adjacent to the VTA1 and NMBR loci), rs10774625 (12q24; p = 2.15×10(-13), in the region of ATXN2,SH2B3 and PTPN11 loci), and rs17421627 (5q14; p?=?7.32×10(-16), adjacent to the MEF2C locus). In two independent samples, locus 12q24 was also associated with coronary heart disease and hypertension. Our population-based genome-wide association study demonstrates four novel loci associated with retinal venular caliber, an endophenotype of the microcirculation associated with clinical cardiovascular disease. These data provide further insights into the contribution and biological mechanisms of microcirculatory changes that underlie cardiovascular disease.     

Cell-penetrating peptide induces leaky fusion of liposomes containing late endosome-specific anionic lipid

Cationic cell-penetrating peptides (CPPs) are a promising vehicle for the delivery of macromolecular drugs. Although many studies have indicated that CPPs enter cells by endocytosis, the mechanisms by which they cross endosomal membranes remain elusive. On the basis of experiments with liposomes, we propose that CPP escape into the cytosol is based on leaky fusion (i.e., fusion associated with the permeabilization of membranes) of the bis(monoacylglycero)phosphate (BMP)-enriched membranes of late endosomes. In our experiments, prototypic CPP HIV-1 TAT peptide did not interact with liposomes mimicking the outer leaflet of the plasma membrane, but it did induce lipid mixing and membrane leakage as it translocated into liposomes mimicking the lipid composition of late endosome. Both membrane leakage and lipid mixing depended on the BMP content and were promoted at acidic pH, which is characteristic of late endosomes. Substitution of BMP with its structural isomer, phosphatidylglycerol (PG), significantly reduced both leakage of the aqueous probe from liposomes and lipid mixing between liposomes. Although affinity of binding to TAT was similar for BMP and PG, BMP exhibited a higher tendency to support the inverted hexagonal phase than PG. Finally, membrane leakage and peptide translocation were both inhibited by inhibitors of lipid mixing, further substantiating the hypothesis that cationic peptides cross BMP-enriched membranes by inducing leaky fusion between them.     

Contrast‐enhanced optical coherence tomography for melanoma detection: An in vitro study

Optical coherence tomography (OCT), with a high‐spatial resolution (<10 microns), intermediate penetration depth (~1.5 mm) and volumetric imaging capability is a great candidate to be used as a diagnostic‐assistant modality in dermatology. At this time, the accuracy of OCT for melanoma detection is lower than anticipated. In this letter, we studied for the first time, the use of a novel contrast agent consist of ultra‐small nanoparticles conjugated to a melanoma biomarker to improve the accuracy of OCT for differentiation of melanoma cells from nonmelanoma cells, in vitro. We call this approach SMall nanoparticle Aggregation‐enhanced Radiomics of Tumor (SMART)‐OCT imaging. This initial proof of concept study is the first step toward the broad utilization of this method for high accuracy all types of tumor detection applications.     

CRISPR/Cas9-mediated engineering of Escherichia coli for n-butanol production from xylose in defined medium

Journal of Industrial Microbiology & Biotechnology - Butanol production from agricultural residues is the most promising alternative for fossil fuels. To reach the economic viability of...