Enhanced thermal, mechanical and fire-retarding properties of polystyrene sulphonate-grafted-nanosilica/polypropylene composites

The addition of pSS-grafted-nanosilica to PP showed enhanced fire retardancy as assessed by mass loss, cone calorimetry and LOI measurements.

Flow Analyses in a Spiral Mandrel Die Assuming Wall Slip

It is often observed in industrial practice that the thickness uniformity of blown film obtained with a given die varies with the type of polymer. We have shown in previous works the importance of the wall slip of polymer melt in the film uniformity. Currently available models of polymer melt flow through spiral mandrel dies neglect the wall slip. The present work considers the slip in flow analyses and predicts the effects of rheological properties on the uniformity; the decreases in melt viscosity and wall slip and the increases in shear thinning and the stress dependence of wall slip reduce the uniformity. The predictions agree well with the experimental results obtained in our previous studies.

Effect of Pressure and Shear Stress on Crystallization Behaviors in Injection Molding

We studied in detail the effects of pressure and shear stress on the crystallization behaviors during injection molding process. Crystallization of isotactic-polypropylene (iPP) was simulated for various injection flow rates. The crystallization started during the filling stage under long filling condition. Moreover, the crystallization in some layers showed two -step growth behavior, while in other layers the crystallization does not progress during the packing -cooling stage. Since pressure becomes very high during molding process under long filling time condition, the change of pressure is the most important factor governing the crystallization.

Study on Viscoelastic Behavior and Extrusion Blow Molding Processability of PP/PE Blends

In this study, extrusion blow molding processability of polypropylene/polyethylene (PP/PE) blends was related to their viscoelastic behavior and morphology under shear flow. The propylene block-copolymer (PP-B) and blends comprising the PP-B and the linear low-density polyethylene (PE), weight fraction of the PE (ϕPE) was up to 20 wt.%, were mainly used for this study. Viscoelastic behavior under shear flow and swelling ratio of the extruded strands were measured by using a capillary type rheometer. Morphology of the strands was observed by TEM. In case of the PP-B, swelling ratio highly depended on shear rate. Coarse aggregated droplets were observed irrespective of shear rate under the measurement. The droplets were ethylene-propylene copolymers (EP) included in the PP-B aggregated at conversing section of the capillary. However, in case of the PP-B/PE blends, swelling ratio showed lower dependence on shear rate as the ϕPE was higher. When the shear rate was low, large droplets were observed and they were highly deformed in the flow direction. On the other hand, when shear rate was high, the droplets were smaller and showed no deformation in the flow direction because the droplets were broken up due to occurrence of high shear stress. Wall thickness of blow molded bottles produced from the PP-B/PE blends was not affected by the throughput rate. It was proportional to the die-core gap. On the other hand, wall thickness of bottles of the PP-B depended on the throughput rate and it was not proportional to the die-core gap. These results suggest that extrusion blow molding processability of polymer blends is good when the dependence of swelling ratio on shear rate is low.

Effect of Material Species on Flash Generation of PPS/GF Composites

Reduction of flash in injection molding is of great concern for manufacturers of electrical parts. In a previous report we have proposed a theoretical model for flash generation. The present study prepares five different poly(phenylene sulfide)/glass fiber composites using three different PPS; linear, branched and crosslinked PPS and measures the length of flash generated in the molding of the composites. Then, we have compared the flash data with a flash parameter defined in the model. This comparison has elucidated that flash length can be related with the flash parameter irrespective of PPS structure, as long as GF content is the same and the clearance of a gas vent is almost identical.

ROS evaluation for a series of CNTs and their derivatives using an ESR method with DMPO

Carbon nanotubes (CNTs) are important materials in advanced industries. It is a concern that pulmonary exposure to CNTs may induce carcinogenic responses. It has been recently reported that CNTs scavenge ROS though non-carbon fibers generate ROS. A comprehensive evaluation of ROS scavenging using various kinds of CNTs has not been demonstrated well. The present work specifically investigates ROS scavenging capabilities with a series of CNTs and their derivatives that were physically treated, and with the number of commercially available CNTs. CNT concentrations were controlled at 0.2 through 0.6 wt%. The ROS scavenging rate was measured by ESR with DMPO. Interestingly, the ROS scavenging rate was not only influenced by physical treatments, but was also dependent on individual manufacturing methods. Ratio of CNTs to DMPO/ hydrogen peroxide is a key parameter to obtain appropriate ROS quenching results for comparison of CNTs. The present results suggest that dangling bonds are not a sole factor for scavenging, and electron transfer on the CNT surface is not clearly determined to be the sole mechanism to explain ROS scavenging.

Paint/Polymer Interface Structure for ABS Injection Moldings

Structure of paint/polymer interface was investigated for the injection molded and compression molded ABS specimens. For the interface of the injection molded specimen, a peculiar “zigzag” structure formation of several tens μm in size was observed. In contrast, the interface structure was not observed for the compression molded specimen and injection molded specimen annealed above the glass transition temperature (Tg). These facts indicate that the interface structure is related to the residual stress and molecular orientation at the surface of the injection molding specimen, because both surface structures would be removed by annealing at temperatures above Tg. The interface structure was strongly dependent on the curing agent concentration. The depth of the structure decreased with increasing curing agent concentration because of decreasing in curing time. At painting temperature between 70°C and 130°C, the depth and pitch were constant. However, below 60°C and above 140°C, the depth and pitch were changed. These results strongly suggest that the interface structure is attributable to relaxation of the surface residual stress and molecular orientation by paint soaking.

Effect of Electric Current on Beads Formation in Electrospinning of Poly(Vinyl Alcohol)

We investigate effects of electric current on formations of beads in electrospinning by changing an electric conductivity of a poly(vinyl alcohol) (PVA) aqueous solution and spinning conditions, such as applied voltage, distance between a tip of needle and a collector, and relative humidity. From the results of experiments done by changing the conductivity of PVA aqueous solution and spinning conditions, we found that a beads formation is suppressed at a lower electric current. Furthermore, when the electrospinnings are performed at a certain constant electric current in various spinning conditions where the applied voltage and tip-collector distance are changed so as to give the same constant electric current, resultant PVA fibers have no beads and almost the same distribution of fiber diameter.

Development of Polymer Extrusion Extruder for Evaluating with a Small Amount of Polymeric Material

We developed the extrusion system to evaluate the extrusion behavior such as the shear viscosity, which is one of basic properties, and the processability of mono/multilayer film with a small amount of polymeric material. In order to measure the shear viscosity, the gear pump, the return path and the pressure sensors were introduced into the extruder with intermeshing co-rotating twin screws. The viscosity could be evaluated on-line from the volumetric flow rate of molten polymer and the pressure drop in the return path before film processing. The capacity of gear pump, the shape and size of return path were optimized to evaluate the viscosity of polymeric material, which generally undergoes shear rate of 10 ∼ 1000 s−1 in the film processing. The apparatus for mono and multilayer film processing consisted of two extruders including the multichannel feedblock and T-die with the manifold and land section. The compact feedblock was designed to receive two feedstreams, so that the product can have two layers. We investigated the on-line viscosity measurement methodology and the processability, which is the neck-in phenomenon for monolayer film and the interface stability for multilayer film, using typical polymer material of 30 grams at once. The viscosity evaluated with our system corresponded with the result of commercial rheometer. It was also confirmed that the processability of mono and multilayer film could be evaluated quantitatively with our system.

Radiological abnormalities and low back pain in gymnasts

Several studies have shown a higher prevalence of radiological abnormalities among gymnasts. However, the types of radiological abnormalities associated with low back pain (LBP) have not been clarified. The hypothesis was that significant relationships between radiological abnormalities and LBP may be revealed by discriminating between the types of MRI abnormalities while considering confounding factors. The subjects were 104 Japanese collegiate gymnasts (men, 70; women, 34). The presence of LBP was evaluated using the questionnaire developed by Osaka City University (OCU Test). Magnetic resonance imaging (MRI) abnormalities were evaluated using T1- and T2-weighted MRI. The prevalence of more than 1 MRI abnormality in gymnasts was 47.1% (49/104). The chi-square test showed that the incidence of lumbar disc degeneration (LDDG) and limbus vertebra was significantly greater in gymnasts with LBP than in gymnasts without LBP. By using logistic regression analysis to analyze the concomitant environmental variables, only LDDG (odds ratio, 2.70; 95% confidence interval, 1.10-6.66) was selected as a statistically significant variable accounting for LBP. In conclusion, LDDG is a predictor for LBP in Japanese collegiate gymnasts.

Insulinoma may mask the existence of Type 1 diabetes

BACKGROUND

Insulinoma is a tumour of insulin-producing cells of the pancreas and is known to be one of the causes of hypoglycaemia. Usually, appropriate removal of the insulinoma results in normalization of blood glucose levels. However, we found novel cases of insulinoma, in which hyperglycaemia developed soon after resection of the insulinoma.

CASE REPORT

We encountered two patients with repeated hypoglycaemia caused by insulinoma. Following removal of the insulinoma, unanticipated hyperglycaemia was observed in both patients. Thereafter, their blood tests revealed low levels of serum C-peptide and high titres of anti-glutamic acid decarboxylase antibody, indicating concomitant Type 1 diabetes. Indeed, histological examination of the resected specimen revealed that one patient showed insulitis in non-tumorous pancreatic tissue in which β-cells had already disappeared. Moreover, inflammatory cells infiltrated the insulinoma, as if it were insulitis of Type 1 diabetes, suggesting the existence of anti-islet autoimmunity.

CONCLUSION

These are first cases of insulinoma associated with underlying Type 1 diabetes. Physicians should be aware of the possibility that insulinoma may mask Type 1 diabetes, and measurement of anti-islet autoantibodies may be helpful to find underlying Type 1 diabetes, such as in these cases. It is pathologically interesting that the immune cell infiltration into insulinoma may be suggestive of anti-islet autoimmunity.

COL11A1 gene is associated with limbus vertebra in gymnasts

Several studies have shown higher frequencies of radiological abnormalities among gymnasts. Recently, the gene encoding the α1 chain of type XI collagen, (COL11A1) (rs 1676486), was associated with lumbar disc herniation in the Japanese population. We hypothesized that there was a significant relationship between abnormal magnetic resonance imaging (MRI) findings of the lumbar spine and the COL11A1 4603C/T gene polymorphism in collegiate gymnasts. Our study participants included 103 Japanese collegiate gymnasts (70 men and 33 women). Radiological abnormalities were evaluated using T1- and T2-weighted MRI. Genotyping for COL11A1 was performed for all the participants. By using logistic regression analysis, we observed significant associations between limbus vertebra and age (adjusted odds ratio=0.51, 95% confidence interval: 0.27-0.96), sporting experience (adjusted odds ratio=1.49, 95% confidence interval: 1.14-1.94), and a TT genotype (adjusted odds ratio=7.83, 95% confidence interval: 1.33-46.03). We conclude that a TT genotype of COL11A1 polymorphism may be a significant risk factor for limbus vertebra in Japanese collegiate gymnasts.

Analyses of laboratory data and establishment of reference values and intervals for healthy elderly people

OBJECTIVE

Protein-energy malnutrition is a common disorder in the elderly. Although serum albumin is commonly used as a nutritional marker, data is lacking on serum albumin levels in the elderly. The purpose of this study was to determine whether serum albumin levels decrease with advancing age and to establish reference value and interval of laboratory data for elderly people (75 years and over).

PARTICIPANTS

Blood samples from 13821 healthy people, 42064 outpatients, and 15959 inpatients were collected during 2008. Blood from 127 of our nutrition support team (NST) patients was also collected during August 2006 and May 2009, and analyzed.

MEASUREMENTS

Serum albumin, hemoglobin, total cholesterol levels and lymphocyte count were determined. We analyzed the change in each parameter in accordance with age, compared the data for elderly people with younger people, and established new reference values. Clinical outcomes were examined depending on the improved reference values.

RESULTS

Albumin was lower in older persons than in younger persons. The estimated reference value and interval were 42 (48-36) g/l in older persons and was much lower in NST patients. Hemoglobin was decreased while cholesterol and lymphocyte count were not changed in older persons: all were markedly decreased in NST patients. Terms of hospital stay were significantly longer and mortality rates were significantly higher in older persons, comparing from above to below using a new reference value of albumin (36 g/l).

CONCLUSIONS

The serum albumin level decreases with advancing age, but it was maintained to some extent in healthy older people. Serum albumin levels related to the clinical outcome. Hemoglobin and cholesterol levels and lymphocyte count were all lower in NST patients. These measurements may be valuable markers of nutritional status and can help in guiding the need for nutritional support.

Cell surface biotinylation by azaelectrocyclization: easy-handling and versatile approach for living cell labeling

Versatile method for living cell labeling has been established. Cell surfaces are initially biotinylated by azaelectrocyclization, and then treated with the fluorescence-labeled avidin or the anti-biotin antibody.

[Maxillary and mandibular fractures. Treatment concepts in maxillofacial surgery]

Maxillary and mandibular fractures are a relatively frequent occurrence due to the exposed location of the jaws and are caused mainly by acts of violence, traffic and recreational accidents. Mandibular fractures can be treated conservatively with dental splints and intermaxillary fixation. Since Michelet, miniplate osteosynthesis via intraoral access has become the method of choice. Champy showed that the monocortical fixation of miniplates at the level of the linea obliqua results in stable osteosynthesis, despite postoperative micro-movements in the fracture gap, and postulated the principle of dynamic compression. Dislocated fractures of the mandibular collum are treated with stable osteosynthesis via an intra- or extraoral approach, while fractures of the mandibular joint are usually treated conservatively and early functional rehabilitation is favored. For mandibular fractures, the principle of load-bearing and load-sharing should be considered, i.e. in the case of sufficient bone and uncomplicated fractures, the bone can bear most of the force, such that miniplates are sufficient (load-sharing). If bones are weakened by atrophy or in the case of infected, comminuted or defect fractures osteosynthesis plates must bear the load alone (load-bearing).

Serum Amyloid a Low-Density Lipoprotein Levels and Smoking Status in Obese Japanese Patients

Serum amyloid A low-density lipoprotein (SAA-LDL) is formed by an oxidative interaction and is considered to be a new marker related to oxidative modification of LDL. As the effect of smoking on oxidized LDL is of concern, this study investigated the association between SAA-LDL and smoking status. A total of 578 Japanese obese outpatients (mean ± SD age 50.5 ± 14.3 years) were studied. Smoking status was examined via a self-reported questionnaire. Cardiometabolic variables, including high-sensitivity C-reactive protein (hsCRP), were analysed in addition to SAA-LDL. There was an increasing trend in SAA-LDL levels from non- to ex- to current smokers, and significantly higher SAA-LDL levels were observed in current smokers versus non-smokers (median SAA-LDL level 36 μg/ml versus 28 μg/ml, respectively). This significant difference was reduced after adjusting for multiple confounders, including lipid levels. Smoking may be associated with increased levels of SAA-LDL in an obese Japanese population, but further studies are needed.

Gas Source Silicon Molecular Beam Epitaxy

Gas source silicon molecular beam epitaxial (Si-MBE) growth is microscopically governed by a disociative adsorption of silicon hydrides, such as Si2H6 source gas molecules on Si surface. The dissociative adsorption generates SiH species on the surface. From this hydride phase, hydrogen desorbs thermaly. The temperature dependence of the growth rate indicated that the hydrogen desorption from the SiH is the rate limiting step. In HBO2 Knudsen cell doping, B adsorbates block the surface migration. Such a blocking effect can be avoided by B2H6 gas dopant, because of the similar incorpration mechanism of B2H6 to that of Si2H6. However, in PH3 gas doping, a crystal quality degradation was observed at a high doping range due to the preferentially high sticking coefficient of PH3 and the resulting surface dangling bond termination. The selective epitaxial growth of a B doped layer using Si2H6 and B2H6 was applied to a novel structured base fabrication for super self-aligned selectively grown base transistor (SSSBT). A successful achievement of the SSSBT fabrication indicates the high potentiality of gas source Si-MBE to the sub-micron size ultra-high speed bipolar large scale integrated (LSI) circuits.

Engulfment of spermatozoa by cumulus cells and the role of CD36

The function of cumulus cells after sperm penetration is not well understood. The present study examined the phagocytic action of cumulus cells on sperm after dispersion of cumulus-oocyte complexes. In a co-incubation system of cauda sperm and cumulus cells, the sperm heads were beginning to vanish after 2.5h and 77%±1.34 of sperm heads had disappeared at 30 h. Most of the sperm heads were engulfed by cumulus cells. Immunofluorescent studies showed that cumulus cells were expressing the CD36 molecule, and sperm were exposing phosphatidylserine (PS). Anti-CD36 antibody and annexin V inhibited the engulfment of sperm by cumulus cells by 26.0% and 40.5%, respectively. These results suggested that the cumulus cells recognized the PS molecules on sperm via CD36 and this molecular interaction possibly triggered the phagocytosis of sperm by cumulus cells. These results suggest that cumulus cells might play a role in inhibiting undesired immune reactions induced by sperm antigens.