Passive cooling techniques through reflective and radiative roofs in tropical houses in Southeast Asia: A literture review

Cooling is one of the major concerns in building tropical houses. This problem is exacerbated by the heat gain of the roof, which constitutes 70% of the total heat gain. The passive cooling technique is one of the innovative practices and technologies that provide buildings with comfortable conditions through natural means. Reflective and radiative processes are the methods used to decrease heat gain by facilitating the elimination of excess heat in a building's interior to maintain a comfortable environment. Given that the potential of these techniques vary from region to region, their application in the tropics should be examined. Exploring these approaches in detail allows us to rethink how to effectively adapt these techniques to overcome the build-up of heat in modern tropical houses in Southeast Asia. This study reviews the physical characteristics of these approaches to guide architects and building designers. Results indicate a great reduction in operational cost. However, the significant differences in the performance of colour and material properties should be considered, given that the selected approach strongly affects the required thermal conditions of a building.     

Regulation of Proteolytic Activity to Improve the Recovery of Macrobrachium rosenbergii Nodavirus Capsid Protein

The causative agent of white tail disease (WTD) in the giant freshwater prawn is Macrobrachium rosenbergii nodavirus (MrNV). The recombinant capsid protein (CP) of MrNV was previously expressed in Escherichia coli, and it self-assembled into icosahedral virus-like particles (VLPs) with a diameter of approximately 30 nm. Extensive studies on the MrNV CP VLPs have attracted widespread attention in their potential applications as biological nano-containers for targeted drug delivery and antigen display scaffolds for vaccine developments. Despite their advantageous features, the recombinant MrNV CP VLPs produced in E. coli are seriously affected by protease degradations, which significantly affect the yield and stability of the VLPs. Therefore, the aim of this study is to enhance the stability of MrNV CP by modulating the protease degradation activity. Edman degradation amino acid sequencing revealed that the proteolytic cleavage occurred at arginine 26 of the MrNV CP. The potential proteases responsible for the degradation were predicted in silico using the Peptidecutter, Expasy. To circumvent proteolysis, specific protease inhibitors (PMSF, AEBSF and E-64) were tested to reduce the degradation rates. Modulation of proteolytic activity demonstrated that a cysteine protease was responsible for the MrNV CP degradation. The addition of E-64, a cysteine protease inhibitor, remarkably improved the yield of MrNV CP by 2.3-fold compared to the control. This innovative approach generates an economical method to improve the scalability of MrNV CP VLPs using individual protease inhibitors, enabling the protein to retain their structural integrity and stability for prominent downstream applications including drug delivery and vaccine development.     

An optimized forwarding protocol for lifetime extension of wireless sensor networks

Optimized routing (from source to sink) in wireless sensor networks (WSN) constitutes one of the key design issues in prolonging the lifetime of battery‐limited sensor nodes. In this paper, we explore this optimization problem by considering different cost functions such as distance, remaining battery power, and link usage in selecting the next hop node among multiple candidates. Optimized selection is carried out through fuzzy inference system (FIS). Two differing algorithms are presented, namely optimized forwarding by fuzzy inference systems (OFFIS), and two‐layer OFFIS (2L‐OFFIS), that have been developed for flat and hierarchical networks, respectively. The proposed algorithms are compared with popular routing protocols that are considered as the closest counterparts such as minimum transmit energy (MTE) and low energy adaptive clustering hierarchy (LEACH). Simulation results demonstrate the superiority of the proposed algorithms in extending the WSN lifetime. Copyright © 2008 John Wiley & Sons, Ltd.     

Chemical and functional properties of the native banana (Musaacuminata × balbisiana Colla cv. Awak) pseudo-stem and pseudo-stem tender core flours

This research was conducted to evaluate the differences in chemical composition and functional profiles of native banana pseudo-stem flour (NBPF) and boiled tender core of the banana pseudo-stem flour (TCBPF). Chemical analyses indicated that the proximate contents (moisture, fat, protein and ash), were significantly higher in TCBPF than in NBPF. The levels of total dietary fibre, insoluble dietary fibre, lignin, hemicellulose and cellulose were all higher in NBPF than TCBPF, while there was no significant difference in soluble dietary fibre. NBPF also had higher contents of polyphenols and flavonoids than TCBPF. Both the antioxidant capacity and the free radical-scavenging capacity were higher in NBPF than in TCBPF. On the other hand, the TCBPF showed significantly higher swelling power, water holding capacity and solubility, although its oil holding capacity was lower than NBPF. We conclude that banana pseudo-stem flour is a potential functional food ingredient for products containing high dietary fibre.     

Loss of ZNF677 Expression Is an Independent Predictor for Distant Metastasis in Middle Eastern Papillary Thyroid Carcinoma Patients

Thyroid cancer incidence has increased in recent decades. Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Approximately 30% of PTC patients develop recurrence or distant metastasis and tend to have poor prognosis. Therefore, the identification of targetable biomarkers in this subset of patients is of great importance. Accumulating evidence indicates that zinc finger protein 677 (ZNF677), which belongs to the zinc finger protein family, is an important effector during the progression of multiple malignancies. However, its role in Middle Eastern PTC patients has not been fully illustrated. Here, we uncovered the molecular mechanism and the clinical impact of ZNF677 expression in a large cohort of more than 1200 Middle Eastern PTC and 15 metastatic tissues. We demonstrated that ZNF677 is frequently downregulated in primary PTC (13.6%, 168/1235) and showed that complete loss of expression of ZNF677 is significantly associated with aggressive clinico-pathological markers such as extrathyroidal extension (p = 0.0008) and distant metastases (p < 0.0001). We also found a significantly higher incidence of ZNF677 loss in primary tumors with distant metastases (33.3%; p < 0.0001) as well as in distant metastatic tissues (46.7%; p = 0.0002) compared to the overall cohort (13.6%). More importantly, PTC with loss of ZNF677 expression showed significantly lower metastasis-free survival (p = 0.0090). Interestingly, on multivariate logistic regression analysis, ZNF677 loss was an independent predictor of distant metastasis in PTC (Odds ratio = 2.60, 95% Confidence interval = 1.20–5.62, p = 0.0155). In addition, we found a significant association between ZNF677 loss and phospho-AKT expression (p < 0.0001). Our functional molecular results suggest that ZNF677 acts as a tumor suppressor, mediating its effect by inhibiting AKT phosphorylation. Taken together, our results highlight the pivotal role played by ZNF677 during carcinogenesis and metastasis formation in Middle Eastern PTC patients.     

Flow rank based probabilistic fair scheduling for wireless ad hoc networks

Fair scheduling is an ideal candidate for fair bandwidth sharing and thereby achieving fairness among the contending flows in a network. It is particularly challenging for ad hoc networks due to infrastructure free operation and location dependent contentions. As there is no entity to serve coordination among nodes, we need a mechanism to overcome inherent unreliability of the network to provide reduced collision and thereby higher throughput and adequate fair allocation of the shared medium among different contending flows. This paper proposes a flow rank based probabilistic fair scheduling technique. The main focus is to reduce the collision probability among the contending flows while maintaining the prioritized medium access for those flows, which ensures a weighted medium access control mechanism based on probabilistic round robin scheduling. Each flow maintains a flow-table upon which the rank is calculated and backoff value is assigned according to the rank of the flow, i.e., lower backoff interval to lower ranked flow. However, flow-table instability due to joining of a new flow, partially backlogged flow, hidden terminal and partially overlapped region exhibits a challenging problem that needs to be mitigated for our mechanism to work properly. We take appropriate measures to make the flow-table stabilized under such scenarios. Results show that our mechanism achieves better throughput and fairness compared to IEEE 802.11 MAC and existing ones.     

Erbium-Doped Fluoroborate Glasses for Near Infrared Broadband Amplifiers

Erbium (Er³⁺)-doped alkali lead tellurofluoroborate (RLTB) glasses were prepared and characterized systematically through optical absorption and emission measurements. The emission spectra in the range 450–900 and 1400–1800 nm were recorded by exciting the samples with 532 nm (Nd : YVO₄ crystal) and 514.5 nm (Ar⁺ laser), respectively. Applying Judd–Ofelt analysis, the intensity parameters have been determined using experimental oscillator strengths of absorption bands. From the Judd–Ofelt intensity parameters, some important fluorescence properties such as spontaneous transition probabilities, radiative lifetimes and luminescence branching ratios for the ⁴S_3/2→⁴I_15/2 (0.55 μm), ⁴S_3/2→⁴I_13/2 (0.85 μm), and ⁴I_13/2→⁴I_15/2 (1.54 μm) emission transitions of Er³⁺ ion in RLTB glasses have been calculated. The continuous pumping of the samples results in fast nonradiative decay through ²H_11/2→⁴F_9/2 (~3500 cm⁻¹) transition, which in turn causes the population of Er³⁺ ions from ²H_11/2 state to the higher ⁴F_3/2 state. The emission cross sections determined for the ⁴I_13/2→⁴I_15/2 (1.54 μm) transition using the McCumber theory are in good agreement with the values obtained from the Judd–Ofelt analysis. From evaluated radiative parameters, it is suggested that these RLTB glasses are more suitable candidates for 0.85 and 1.54 μm broadband optical amplifiers.     

Fate of the antiretroviral drug tenofovir in agricultural soil

Tenofovir (9-(R)-(2-phosphonylmethoxypropyl)-adenine) is an antiretroviral drug widely used for the treatment of human immunodeficiency virus (HIV-1) and Hepatitis B virus (HBV) infections. Tenofovir is extensively and rapidly excreted unchanged in the urine. In the expectation that tenofovir could potentially reach agricultural lands through the application of municipal biosolids or wastewater, and in the absence of any environmental fate data, we evaluated its persistence in selected agricultural soils. Less than 10% of [adenine-8-¹⁴C]-tenofovir added to soils varying widely in texture (sand, loam, clay loam) was mineralized in a 2-month incubation under laboratory conditions. Tenofovir was less readily extractable from clay soils than from a loam or a sandy loam soil. Radioactive residues of tenofovir were removed from the soil extractable fraction with DT₅₀s ranging from 24 ± 2 to 67 + 22 days (first order kinetic model) or 44 + 9 to 127 + 55 days (zero order model). No extractable transformation products were detectable by HPLC. Tenofovir mineralization in the loam soil increased with temperature (range 4 °C to 30 °C), and did not occur in autoclaved soil, suggesting a microbial basis. Mineralization rates increased with soil moisture content, ranging from air-dried to saturated. In summary, tenofovir was relatively persistent in soils, there were no extractable transformation products detected, and the response of [adenine-8-¹⁴C]-tenofovir mineralization to soil temperature and heat sterilization indicated that the molecule was biodegraded by aerobic microorganisms. Sorption isotherms with dewatered biosolids suggested that tenofovir residues could potentially partition into the particulate fraction during sewage treatment.     

Determination of Porcine Contamination in Laboratory Prepared dendeng Using Mitochondrial D-Loop686 and cyt b Gene Primers by Real Time Polymerase Chain Reaction

The identifications of species in meat products have created interests since these foods became the target of forgery and fraud in the market. The presence of pork in food products is not allowed for the Muslim community. Hence, an analysis is necessary to detect the presence of pork in processed meat products, such as in dendeng (dried meat) product. Real time polymerase chain reaction using mitochondrial displacement loop686 and cytochrome b (cytb) gene primers was used to identify specific pork DNA among other four types of DNA species; namely beef, chicken, goat, and horse. This method was also used to identify pork DNA in the laboratory processed pork-beef dendeng as well as commercial dendeng from market. The results showed that real time polymerase chain reaction using displacement loop686 and cytb gene primers were able specifically to distinguish between pork DNA and the other species. The lowest concentration of 0.5% of pork DNA in a mixture of pork-beef processed products of dendeng was able to be detected by both primers with the product amplification of 114 and 134 bp (base pair) for the displacement loop686 and 149 bp for cytb gene, respectively. High sensitivity was also obtained when both primers were applied with the lowest detection limit of 5 pg/µL pork DNA. The results of the six commercial dendeng amplification using both primers showed no amplified products present, meaning that these products do not contain porcine DNA.