Dithienocarbazole‐Based Ladder‐Type Heptacyclic Arenes with Silicon,Carbon, and Nitrogen Bridges: Synthesis,Molecular Properties,Field‐Effect Transistors,and Photovoltaic Applications

A new class of ladder‐type dithienosilolo‐carbazole ( DTSC ), dithienopyrrolo‐carbazole ( DTPC ), and dithienocyclopenta‐carbazole ( DTCC ) units is developed in which two outer thiophene subunits are covalently fastened to the central 2,7‐carbazole cores by silicon, nitrogen, and carbon bridges, respectively. The heptacyclic multifused monomers are polymerized with the benzothiadiazole ( BT ) acceptor by palladium‐catalyzed cross‐coupling to afford three alternating donor‐acceptor copolymers poly(dithienosilolo‐carbazole‐alt‐benzothiadiazole) ( PDTSCBT) , poly(dithienocyclopenta‐carbazole‐alt‐benzothiadiazole) ( PDTCCBT), and poly(dithienopyrrolo‐carbazole‐alt‐benzothiadiazole) ( PDTPCBT) . The silole units in DTSC possess electron‐accepting ability that lowers the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of PDTSCBT , whereas stronger electron‐donating ability of the pyrrole moiety in DTPC increases the HOMO and LUMO energy levels of PDTPCBT . The optical bandgaps (E_g^opt) deduced from the absorption edges of thin film spectra are in the following order: PDTSCBT (1.83 eV) > PDTCCBT (1.64 eV) > PDTPCBT (1.50 eV). This result indicated that the donor strength of the heptacyclic arenes is in the order: DTPC > DTCC > DTSC . The devices based on PDTSCBT and PDTCCBT exhibited high hole mobilities of 0.073 and 0.110 cm² V^?1 s^?1, respectively, which are among the highest performance from the OFET devices based on the amorphous donor‐acceptor copolymers. The bulk heterojunction photovoltaic device using PDTSCBT as the p‐type material delivered a promising efficiency of 5.2% with an enhanced open circuit voltage, V_oc, of 0.82 V.     

Risk factors associated with elevated serum pancreatic amylase levels during hemodialysis

Elevated levels of serum pancreatic enzymes are frequently observed in hemodialysis (HD) patients. The complex hemodynamic, biochemical, and physiological alterations in uremia were speculated to cause excessive release of pancreatic enzymes beyond decreased renal clearance. However, hemodynamic factors are seldom explored in this aspect. We performed the study to evaluate the association between intradialytic hemodynamic change and elevated serum pancreatic amylase (SPA). Eighty‐three prevalent HD patients without any clinical evidence of acute pancreatitis underwent pre‐HD and post‐HD blood sampling for serum pancreatic enzyme levels. Demographic, biochemical, and hematological data were collected from patient record review. Hemodialysis information including intradialytic blood pressure changes and ultrafiltration (UF) amount were collected and averaged for 1 month before the blood sampling day. Patients with elevated SPA during the HD session had greater mean systolic blood pressure and mean arterial pressure reduction, greater UF volume, greater pre‐HD blood urea nitrogen and serum creatinine, higher serum phosphorus, lower pre‐HD serum total CO₂, and lower left ventricle ejection fraction (LVEF). Using multivariate linear and logistic regression analysis, the independent predictors of elevated SPA were determined to be mean arterial pressure reduction during HD, mean UF amount, pre‐HD serum total CO₂, and LVEF. Greater blood pressure reduction during HD, greater UF volume, lower pre‐HD serum total CO₂, and lower LVEF were significantly associated with elevated SPA during HD. This suggests that hemodynamic factors contribute to elevated serum pancreatic enzymes in HD patients.     

Sonochemical synthesis and shape change of colloidal CdSe nanocrystals by high-intensity ultrasound

In this article, we have developed the synthesis of CdSe nanocrystals by the introduction of high-intensity ultrasound combined with an anionic surfactant (sodium dodecyl sulfate, SDS). TEM, XRD, and SEM EDS confirmed the successful synthesis of CdSe nanoparticles with zinc blende crystal phase. UV, PL, and TEM revealed that large particles settled to the bottom of the reaction flask. In the lower part precipitate, nanorods of different aspect ratios were also observed. The CdSe nanorods were formed by self-assembly due to the SDS surfactant and high-intensity ultrasound. A three-stage mechanism for the synthesis of CdSe nanorods was proposed. The effect of SDS concentration on the shape of nanorods was also investigated. At medium concentrations of SDS (0.2 M), one-dimensional CdSe nanorods with different aspect ratios were obtained. When using low concentrations of SDS (0.1 M), two-dimensional square-like crystals were observed due to all growth crystal faces having roughly the same surface energy.     

Bipolar switching characteristics of low-power Geo resistive memory

We reported an ultra low-power resistive random access memory (RRAM) combining a low-cost Ni electrode and covalent-bond GeO_x dielectric. This cost-effective Ni/GeO_x/TaN RRAM device has very small set power of 2 μW, ultra-low reset power of 130 pW, greater than 1 order of magnitude resistance window, and stable retention at 85 °C. The current flow at low-resistance state is governed by Poole-Frenkel conduction with electrons hopping via defect traps, which is quite different from the filament conduction in metal-oxide RRAM.     

Foam Filters Used in Gravity Casting

Ceramic foam filters are normally used for reducing the velocity of liquid metal in the design of runner systems. In this study, four designs of the runner system with various orientations of foam filters were explored, and their effect on the velocity of the melt was estimated by a casting experiment and computational modeling. In the casting experiment, the free-fall trajectory and metal weighing methods were employed for measuring apparent velocity and flow rate, respectively. Using Forchheimer’s equation, a porous material such as a foam filter was simulated. The modeling result was validated by the experiment. For the efficient use of a foam filter in a running system with a high flow rate but low exit velocity, an optimized design is recommended.     

GMI,an Immunomodulatory Peptide from Ganoderma microsporum,Restrains Periprosthetic Joint Infections via Modulating the Functions of Myeloid-Derived Suppressor Cells and Effector T Cells

Periprosthetic joint infections (PJIs) caused by Staphylococcus aureus infection are difficult to treat due to antibiotic resistance. It is known that the biofilms from methicillin-resistant S. aureus (MRSA) promote expansion of myeloid-derived suppressor cells (MDSCs) to suppress T-cell proliferation and benefit bacterial infections. This study finds that GMI, a fungal immunomodulatory peptide isolated from Ganoderma microsporum, suppresses MDSC expansion to promote the proliferation of cytotoxic T cells. The enhancement is likely attributed to increased expression of IL-6 and TNF-α and reduction in ROS expression. Similar beneficial effects of GMI on the suppression of MDSC expansion and IL-6 expression are also observed in the whole blood and reduces the accumulation of MDSCs in the infected bone region in a mouse PJI infection model. This study shows that GMI is potentially useful for treating S. aureus-induced PJIs.     

A polynomial regression model for the response of various accelerating techniques on maize wine maturation

Statistical analysis was conducted to interpret the recently observed effects of various accelerating techniques on maize wine maturation (Chang, A. C. (2004). The effects of different accelerating techniques on maize wine maturation. Food Chemistry, 86, 61). Instead of the previously reported simple linear relationship between the concentrations of the key components of maize wine in the final product and the number of treatments or the dosage, various types of non-linear behaviours were observed. A general polynomial regression model is used to describe these behaviours, and the adjustable parameters were estimated from the experimental data. The performance of the proposed regression model, which plays a key role in the design of an efficient accelerating process, was satisfactory. Some specific variations of the key components of maize wine, as a function of the number of treatments or the dosage, were observed.     

Influence of fruit variety, harvest technique, quality sorting, and storage on the native microflora of unpasteurized apple cider

Apple variety, harvest, quality sorting, and storage practices were assessed to determine their impact on the microflora of unpasteurized cider. Seven apple varieties were harvested from the tree or the ground. The apples were used fresh or were stored at 0 to 4 degrees C for < or = 5 months and were pressed with or without quality selection. Cider yield, pH, Brix value, and titratable acidity were measured. Apples, postpressing apple pomace, and cider samples were analyzed for aerobic bacteria, yeasts, and molds. Aerobic bacterial plate counts (APCs) of ciders from fresh ground-picked apples (4.89 log CFU/ml) were higher than those of ciders made from fresh, tree-picked apples (3.45 log CFU/ml). Quality sorting further reduced the average APC to 2.88 log CFU/ml. Differences among all three treatment groups were significant (P < 0.0001). Apple and pomace microbial concentrations revealed harvest and postharvest treatment-dependent differences similar to those found in cider. There were significant differences in APC among apple varieties (P = 0.0001). Lower counts were associated with varieties exhibiting higher Brix values and higher titratable acidity. Differences in APC for stored and fresh apples used for cider production were not significant (P > 0.05). Yeast and mold counts revealed relationships similar to those for APCs. The relationship between initial microbial load found on incoming fruit and final cider microbial population was curvilinear, with the weakest correlations for the lowest apple microflora concentrations. The lack of linearity suggests that processing equipment contributed to cider contamination. Tree-picked quality fruit should be used for unpasteurized cider production, and careful manufacturing practices at cider plants can impact both safety and quality of the final product.     

Enhanced airborne polychlorinated biphenyl (PCB) concentrations and chlorination downwind of Lake Ontario

Air samples were collected simultaneously at three sites downwind of Lake Ontario and at a control site near Lake Erie from March to July of 1999. The Lake Erie site (Stockton, NY) had PCB concentrations similar to rural Integrated Atmospheric Deposition Network (IADN) sampling sites across the Great Lakes, exhibited limited seasonal variation, and approximates regional background. Samples taken along Lake Ontario's southeastern shore (Rice Creek and Sterling, NY) had elevated PCB concentrations averaging approximately 1 ng/m3 and were more chlorinated than air collected at IADN sites and at Stockton. Air samples from Potsdam (approximately 75 km inland) had similar concentrations but were less chlorinated. Clausius-Clapeyron plots revealed a strong correlation between PCB fugacity and temperature near Lake Ontario; however, the extent of chlorination of the air samples rules out volatilization from the lake as a major source. It is hypothesized that volatilization from local surfaces, enriched in higher chlorinated congeners by meteorological or geographic factors, drives both the concentration and composition of airborne PCBs along Lake Ontario's southeastern shore.     

Yam affects the antioxidative and gel‐forming properties of surimi gels

The antioxidative activities and textural properties of pollock surimi gels containing four different yams were determined to evaluate the potential of using yam as a health ingredient and an alternative source for starch in surimi‐based seafoods. Surimi gels containing 20% fresh yam showed higher α,α‐diphenyl‐β‐pricryl‐hydrazyl (DPPH) radicals scavenging activities and total phenolic contents than the gels without yam. Two tested cultivars, 70W34 and 70W35, did not show significant reductions in antioxidative activities when used in surimi gel while three other cultivars revealed species‐dependant declines in both the DPPH scavenging activities and total phenolic contents. The surimi gel containing the cultivar 70R20 showed the highest breaking forces and deformations. In general, 20% fresh yam could be used to form a yam‐containing surimi gel having similar textural properties with a potato starch containing pollock surimi gel. The dried yam powders might be used at the amount of 30% fresh yam equivalent without causing significant losses of the textural properties of pollock surimi gels. Copyright © 2005 Society of Chemical Industry