Generating Synthetic Rainfall Total Using Multivariate Skew-<Emphasis Type="Italic">t</Emphasis> and Checkerboard Copula of Maximum Entropy

This study aims to test the appropriateness of multivariate skew-t copula and checkerboard copula of maximum entropy in generating monthly rainfall total data. The generation of synthetic data is important, as it provides hypothetical data in areas for which data availability remains limited. Three selected meteorological stations in Kelantan, Malaysia, Stesen Pertanian Melor, Rumah Pam Salor, and Ladang Lepan Kabu, are considered in this study. Monthly rainfall total data for the driest and wettest months in the year are tested in this study. For these three stations, the identified month with the least total of rainfall received (driest) is May, while the month with the highest total of rainfall received (wettest) is November. The data is fitted to gamma distribution with the corresponding parameters estimated. The observed data will be transformed to be in unit uniform using the gamma marginal. The resulting data is compared to simulated uniform data generated using multivariate skew-t copula and checkerboard copula of maximum entropy models based on the correlation values of the observed and simulated data. Next, the Kolmogorov-Smirnov test is used to assess the fit between the observed and generated data. The results show that the values of simulated correlation coefficients do not differ much for gamma distribution, multivariate skew-t, and maximum entropy approaches. This implies that the multivariate skew-t and maximum entropy may be used to generate monthly rainfall total for cases in which actual data is unavailable.     

Recent Advances on the Role of Brain-Derived Neurotrophic Factor (BDNF) in Neurodegenerative Diseases

Neurotrophins, such as brain-derived neurotrophic factor (BDNF), are essential for neuronal survival and growth. The signaling cascades initiated by BDNF and its receptor are the key regulators of synaptic plasticity, which plays important role in learning and memory formation. Changes in BDNF levels and signaling pathways have been identified in several neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease, and have been linked with the symptoms and course of these diseases. This review summarizes the current understanding of the role of BDNF in several neurodegenerative diseases, as well as the underlying molecular mechanism. The therapeutic potential of BDNF treatment is also discussed, in the hope of discovering new avenues for the treatment of neurodegenerative diseases.     

Chondrosarcoma of the nasal septum

A case of chondrosarcoma of the nasal septum is presented with the result of treatment. The patient was admitted for a growth in the nose of four years' duration. Fine needle aspiration for cytological examination was suggestive of squamous cell carcinoma. She was treated with lateral rhinotomy and wide excision followed by septorhinoplasty. Histological examination showed that the lesion was chondrosarcoma. The patient remained free of disease 26 months after surgery.     

Calcium ion-selective electrode based on the facile synthesis of CuO over Cu wires

Here, we report a simple, cost-effective and repeatable process to grow copper(II) oxide (CuO) over a Cu wire. Characterization of the prepared CuO structures revealed a pure phase of CuO with high-density nanostructures. By applying dibenzo-18-crown-6 as an ionophore, CuO (as a solid contact, SC) was developed into a calcium (Ca²⁺) ion-selective electrode (ISE) with a linear activity range between 10 μM and 100 mM, an average Nernstian slope (sensitivity) of 32.3?±?1.3 mV/decade, and a lower limit of detection (LOD) of 10 μM. When tested for selectivity among three ions (magnesium, nickel, and sodium) in addition to the target ion, the electrode had better selectivity toward Ca²⁺ ions. We were able to demonstrate that the proposed Cu/CuO electrode was stable within the pH range from 5.0 to 9.0 for a period of 60 days. Our results of the proposed SC-ISE exhibit a good potential response and acceptable stability, and they show a clear indication that Cu/CuO nanostructures (SC-ISE) can be used as an ion-to-electron transducer for low-cost solid-state potentiometric sensors.

     

Effect of Applied Load in the Nanoindentation of Gold Ball Bonds

We have analyzed the effects of nanoindentation at applied loads of 10 mN and 20 mN on the micromechanical properties of gold (Au) ball bonds with and without cracks. The depth profile and the plastic zone size for each indentation were determined to identify the substrate effect and its relationship with the observed micromechanical properties. The substrate effect occurred for indentations at 20 mN applied load, but did not occur near cracks for either 10 mN or 20 mN loads. Because of the substrate effect and the presence of cracks, the average hardness or yield strength decreased for indentations on Au ball bonds. Therefore, to minimize the substrate effect, an applied load of 10 mN is best for characterizing Au ball bonds.     

Novel epoxidized natural rubber toughened polyamide 6/halloysite nanotubes nanocomposites

A novel ternary epoxidized natural rubber (ENR-50) toughened polyamide 6/halloysite nanotubes (PA6/HNTs) nanocomposites were successfully prepared by extrusion followed by injection molding. The HNTs revealed a favourable interaction with the PA6 matrix as seen by the improvement in mechanical properties and presence of a new FTIR vibrational peak. The ENR-50 showed an improvement of the impact strength up to 300% with a super tough characteristic at only 15 wt% ENR-50. The naturally occurring nanotubes proved to be a suitable candidate to replace other synthetic nanotubes.     

Thermal properties and processability of talc‐ and calcium carbonate‐filled poly(vinyl chloride) hybrid composites

The main objective of this investigation was to study and compare the thermal rigidity, thermal stability, and processability of poly(vinyl chloride) (PVC) composites filled with single fillers of talc and uncoated ground CaCO₃ (SM 90) or a hybrid filler consisting of talc/SM 90. To produce the composites, the PVC resin, fillers, and other additives were dry‐blended in a laboratory mixer before being milled into sheets by using a two‐roll mill. Test specimens were prepared by compression molding, after which the thermal properties and processability of the composites were determined. Single and hybrid filler loadings used were fixed at 30 phr (parts per hundred parts of resin). Talc‐filled PVC composite showed slightly better thermal stability and rigidity than the composite filled with SM 90, and its thermal stability and rigidity slightly decreased with SM 90 content increasing from 5 to 25 phr in order to replace talc filler in the hybrid composites. The fusion time of talc‐filled PVC composite was shorter than that of SM 90‐filled PVC composite; thus, the fusion time of hybrid composites increased with increasing SM 90. The fusion torque showed an opposite behavior. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers     

Study of processability of poly(vinyl chloride): Effects of acrylic and chlorinated polyethylene impact modifiers,oil palm empty fruit bunch fiber,and mixing temperature

The influence of acrylic impact modifier, chlorinated polyethylene (CPE) impact modifier, oil palm empty fruit bunch (OPEFB) fiber, and mixing temperature on the processability of poly(vinyl chloride) (PVC) compounds was investigated. The acrylic impact modifier was the most efficient additive in reducing the fusion time of the PVC, followed by the OPEFB fiber and the CPE impact modifier, whereas OPEFB was the most efficient in decreasing the melt viscosity of the compounds, followed by CPE and acrylic. A PVC compound containing 9 phr of CPE and 40 phr of OPEFB had high values of fusion time and end torque. The fusion time and melt viscosity of all of the PVC compounds decreased with increasing mixing temperature. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers.     

Thermo-mechanical and antioxidant properties of eugenol-loaded carrageenan-cellulose nanofiber films for sustainable packaging applications

This study aimed to investigate the thermomechanical and antioxidant properties of an active film composed of carrageenan and cellulose nanofibers incorporating (0.1%v/v–0.5%v/v) eugenol (Eu), intended for active packaging applications. The mechanical, physical, morphology, and thermal properties of the active film were extensively characterized, and the antioxidant activity was monitored over a 34-day-storage period. Broido's model was employed to assess the thermomechanical properties and activation energy of the films towards the Eu structure in carrageenan and cellulose nanofiber film. The findings revealed that the addition of Eu had a negative impact on the activation energy of the film's decomposition while positively affecting the release of antioxidants during storage. The film containing 0.4% Eu demonstrated optimal physical and mechanical characteristics, including a tensile strength of 38.08 ± 2.06 MPa and elongation at break of 21.95% ± 9.02%. Furthermore, the SGC-0.4% (SGC stand for Semi refined carragenan + Glycerol + Cellulose nanofiber) Eu film exhibited a higher activation energy (365.82 kJ/mol), suggesting enhanced stability and durability compared with other films. The film with 0.4% Eu content showed the highest release rate of polyphenols (614.9290 mg gallic acid/L sample) up to 28 days of storage. Additionally, it exhibited a 58% efficiency of radical scavenging activity. Overall, these results highlight the potential of the SGC-0.4% Eu film as a biodegradable packaging solution that offers prolonged food shelf life.