Magnetic and Tunable Sound Absorption Properties of an In-Situ Prepared Magnetorheological Foam

Conventional polyurethane foam has non-tunable sound absorption properties. Here, a magneto-induced foam, called magnetorheological (MR) foam, was fabricated with the feature of being able to tune sound absorption properties, primarily from the middle- to higher-frequency ranges. Three different samples of MR foams were fabricated in situ by varying the concentration of Carbonyl Iron Particles (CIPs) (0, 35, and 75 wt.%). The magnetization properties and tunable sound absorption characteristics were evaluated. From the magnetic saturation properties, the results showed very narrow and small coercivity of hysteresis loops relative to the soft magnetic properties of the CIPs. MR foam with 75 wt.% CIPs showed a higher magnetic saturation at 91.350 emu/g compared to MR foam with 35 wt.% CIPs at 63.896 emu/g. For tunable sound absorption testing, the effect of ‘shifting’ to higher frequency was also observed when the magnetic field was applied, which was ~10 Hz for MR foam with 35 wt.% CIPs and ~130 Hz for MR foam with 75 wt.% CIPs. As the latest evolution of semi-active noise control materials, the results from this study are valuable guidance for the advancement of MR-based devices.     

Interleukin-23 and its correlation with disease activity,joint damage,and functional disability in rheumatoid arthritis

The purpose of this study was to compare the serum interleukin (IL)-23 levels between rheumatoid arthritis (RA) patients and healthy controls and to determine the correlation of IL-23 levels with disease activity, joint damage and functional disability in RA. Serum samples were obtained from 45 patients with RA and 45 healthy controls. The enzyme-linked immunosorbent assay method was used for quantitative analysis of IL-23. All the RA patients were assessed for disease activity based on the 28-joint disease activity score, joint damage based on modified Sharp score, and functional ability using the Health Assessment Questionnaire–Disability Index. The mean serum IL-23 level was much higher among the RA patients (24.50 ± 13.98 pg/mL) compared to the controls (5.98 ± 3.40 pg/mL; p < 0.01). There was a significant positive relationship between IL-23 levels and disease activity and questionnaire scores (p = 0.003 and 0.020, respectively). On logistic regression analysis, IL-23 levels were significantly higher in patients with moderate to high disease activity (p = 0.008, odds ratio = 1.073, 95% confidence interval = 1.019–1.130) and patients with significant functional disability (p = 0.008, odds ratio = 1.085, 95% confidence interval = 1.021–1.153). RA patients have significantly higher levels of serum IL-23. The IL-23 levels correlate well with disease activity and functional disability but not with radiographic joint damage.     

Oppositely Synchronized Lamellar Bending in Poly(l‐lactic acid) Versus Poly(d‐lactic acid) Blended with Poly(1,4‐butylene adipate)

Lamellar bending habits, as influenced by molecular‐chain chirality, in packing into dendritic spherulites with specific optical patterns are discussed using two model polymers of opposite chirality that are blended with a common polymer as examples: i) poly(l ‐lactic acid)/poly(butylene adipate) (PLLA/PBA) and ii) poly(d ‐lactic acid)/PBA (PDLA/PBA) blends. The bending habits in the spherulites of PLLA or PDLA blended with PBA are dictated by the chirality, specifically the counterclockwise and clockwise directions for the PLLA/PBA (50:50) and PDLA/PBA (50:50) blends, respectively. Straight lamellae in spiral lozenge crystals are packed with crystal aggregates of PLLA on top of the flat‐on lamellae plates acting as a basal plane during crystallization at T_c; spiral lozenge‐crystal frameworks are surrounded by needle‐like crystals resembling PBA crystals.

     

Impact of a Spatial Repellent on Malaria Incidence in Two Villages in Sumba,Indonesia

A randomized, double-blinded, placebo-controlled study was conducted to examine the effect of spatial repellent (SR) in households at risk of malaria in Indonesia. Following presumptive radical cure for malaria in 180 adult men representing sentinels of new infection in four clusters within two villages, all households were given either metofluthrin or placebo mosquito coils. Weekly blood smear screening and human-landing mosquito catches were done throughout the 6 months intervention. Malaria infections occurred in 61 subjects living in placebo households and 31 subjects living in SR coil households, suggesting a 52% protective effect of SR. Likewise, anopheles indoor human landing rates were 32% lower in homes receiving SR coils. Differences in the malaria attack rate between SR- and placebo-treated homes was significant when not accounting for the effects of clustering. When the analysis was adjusted for intra-cluster correlation, the differences between SR- and placebo-treated homes were not statistically significant. The findings provide evidence of SR public health benefit and support a larger trial statistically powered to detect those effects.     

The protective effect of aqueous extracts of roselle (Hibiscus sabdariffa L. UKMR-2) against red blood cell membrane oxidative stress in rats with streptozotocin-induced diabetes

OBJECTIVES:

The aim of this study was to investigate the protective effects of aqueous extracts of roselle (Hibiscus sabdariffa L. UKMR-2) against red blood cell (RBC) membrane oxidative stress in rats with streptozotocin-induced diabetes.

METHODS:

Forty male Sprague-Dawley rats weighing 230-250 g were randomly divided into four groups (n = 10 rats each): control group (N), roselle-treated control group, diabetic group, and roselle-treated diabetic group. Roselle was administered by force-feeding with aqueous extracts of roselle (100 mg/kg body weight) for 28 days.

RESULTS:

The results demonstrated that the malondialdehyde levels of the red blood cell membranes in the diabetic group were significantly higher than the levels in the roselle-treated control and roselle-treated diabetic groups. The protein carbonyl level was significantly higher in the roselle-treated diabetic group than in the roselle-treated control group but lower than that in the diabetic group. A significant increase in the red blood cell membrane superoxide dismutase enzyme was found in roselle-treated diabetic rats compared with roselle-treated control rats and diabetic rats. The total protein level of the red blood cell membrane, osmotic fragility, and red blood cell morphology were maintained.

CONCLUSION:

The present study demonstrates that aqueous extracts of roselle possess a protective effect against red blood cell membrane oxidative stress in rats with streptozotocin-induced diabetes. These data suggest that roselle can be used as a natural antioxidative supplement in the prevention of oxidative damage in diabetic patients.     

Peripheral blood gene expression profile of atherosclerotic coronary artery disease in patients of different ethnicity in Malaysia

The molecular basis of coronary artery disease (CAD) has been widely studied in the western world but there is no published work on the Malaysian population. This study looked at the global gene expression profiling of the peripheral blood of patients with CAD from the 3 main ethnic groups in Malaysia. Male subjects selected were based on angiographically confirmed CAD (≥50% stenosis) and normal control subjects (0% stenosis) with age range of 55.6±5.3 and 51.0±5.5years, respectively. The global gene expression of 12 angiographically documented CAD patients and 11 matched control subjects were performed. The combined group samples identified 6 up regulated differential expression (DE) genes (GHRL, LTA, CBS, HP, ITGA2B, and OLR1) and 12 down regulated DE genes (IL18R1, ITGA2B, IL18RAP, HP, OLR1, SOD2 ITGB3, IL1B, MMP9, PLA2G7, UTS2, and CBS) to be involved in CAD at the fold change of 1.3 with fault discovery rate (FDR) of 1%. Three genes, MMP9, IL1B, and SOD2 were down regulated in all the 3 ethnic groups making them potential biomarker candidates for CAD across all three ethnicities. Further verification in a cohort study is needed.     

Risk modification of colorectal cancer susceptibility by interleukin-8 -251T>A polymorphism in Malaysians

AIM: To investigate the allele and genotype frequencies and associated risk of interleukin (IL)-8 -251T>A polymorphism on colorectal cancer (CRC) susceptibility risk.METHODS: Peripheral blood samples of 255 normal controls and 255 clinically and histopathologically confirmed CRC patients were genotyped for IL-8 -251T>A polymorphism employing allele-specific polymerase chain reaction. The relative association of variant allele and genotypes with CRC susceptibility risk was determined by calculating the odds ratios (ORs). Corresponding χ² tests on the CRC patients and controls were carried out and 95% confidence intervals (CIs) were determined using Fisher’s exact test. The allele frequencies and its risk association were calculated using FAMHAP, haplotype association analysis software.RESULTS: On comparing the frequencies of genotypes of patients and controls, the homozygous variant AA was significantly higher in CRC patients (P = 0.002) compared to controls. Investigation on the association of the polymorphic genotypes with CRC susceptibility risk, showed that the homozygous variant IL-8 -251AA had a significantly increased risk with OR 3.600 (95% CI: 1.550-8.481, P = 0.001). In the case of allele frequencies, variant allele A of IL-8 -251 showed a significantly increased risk of CRC predisposition with OR 1.32 (95% CI: 1.03-1.69, P = 0.003).CONCLUSION: Variant allele and genotype of IL-8 (-251T>A) was significantly associated with CRC susceptibility risk and could be considered as a high-risk variant for CRC predisposition.     

Bi-doping improves the magnetic properties of zinc oxide nanowires

Room-temperature ferromagnetism in the large and direct bandgap diluted magnetic semiconductor zinc oxide (ZnO) is attributed to the intrinsic defects and p-orbital–p-orbital (p–p) coupling interaction. However, due to oxidation, the ferromagnetism induced by defects is unstable. In the present work, the solution process synthesis route was utilized to grow pristine and bismuth-doped, highly crystalline ZnO nanowire (ZnO NW)-based samples. The FE-SEM images showed that the grown ZnO NWs have a preferred orientation along the c-axis in the (001) direction due to the anisotropic crystal nature of ZnO. X-ray photoelectron spectroscopy (XPS) confirmed the presence of Bi, and at a higher doping content, the bismuth oxide phase appeared. The XRD patterns showed the wurtzite crystal structure, and the large intensity of the (002) peak suggests that most of the reflection was from the top hexagonal face of the NWs, and thus, the wires are predominantly aligned along the c-axis. The TEM analysis further confirmed the crystal growth direction along the (001) direction. The UV-Visible absorption and PL measurements also showed a decrease in the bandgap with an increase in doping concentration, which may be associated with the sp–d exchange interaction between the localized d-electrons and band electrons of the Bi ions. Bi-doping tended to increase the PL intensity in the visible region. The magnetic properties measured by SQUID at 4 and 300 K showed ferromagnetic behaviour for both the pristine and Bi-doped samples. However, the saturation magnetization for the Bi-doped samples was higher compared to that of the pristine ZnO samples until the threshold doping value. The obtained results demonstrated that Bi-doping can be used to tune both the optical and magnetic properties of ZnO NWs, hence paving the way for future spintronics and spin-polarized optoelectronics applications.

Room-temperature ferromagnetism in the large and direct bandgap diluted magnetic semiconductor zinc oxide (ZnO) is attributed to the intrinsic defects and p-orbital–p-orbital (p–p) coupling interaction.