Universal Cycles for Minimum Coverings of Pairs by Triples, with Application to 2-Radius Sequences

A new ordering, extending the notion of universal cycles of Chung {\em et al.} (1992), is proposed for the blocks of $k$-uniform set systems. Existence of minimum coverings of pairs by triples that possess such an ordering is established for all orders. Application to the construction of short 2-radius sequences is given, with some new 2-radius sequences found through computer search.Comment: 18 pages, to appear in Mathematics of Computatio

Synthesis of heat integrated resource conservation networks

Huge amount of energy and fresh resources (i.e. water, chemicals, solvents) are consumed by process industries to achieve the desired product throughput and quality. The current drive toward sustainability and business competitiveness has driven the process industries to effectively use these resources. Thus, resource conservation activities have become the centre of attention as compared to conventional end-of-pipe waste treatment system. Process integration has been commonly used as an effective tool for resource conservation and waste reduction. One of the most established areas of process integration is concentration- and property-based resource conservation networks (RCNs). Most works in RCNs synthesis do not consider temperature as part of process constraints. However, in many cases, temperature is an important design parameter. Thus, simultaneous consideration of mass/property and heat recovery should be addressed. Earlier works in this area have been mainly focusing on heat integrated water networks (HIWNs).However, these methods cannot be applied for property-based RCNs, as they are limited to “chemo-centric” system. Clearly, a more generic approach is needed for the synthesis of concentration- and property-based heat integrated resource conservation networks (HIRCNs). This thesis presents novel and generic methodologies for the synthesis of concentration- and property-based HIRCNs with variable operating parameters (i.e. flowrates, temperatures and properties). Firstly, a new generic overall methodology for concentration- and property-based HIRCNs is established. Next, a general framework for synthesis of HIRCNs with and without heat of mixing is presented. Based on this framework, new methodology for the synthesis of HIRCNs with and without heat of mixing are established respectively. Moreover, a revised floating pinch method is developed for utilities targeting in heat exchanger networks (HENs) with varying temperature range, and it is incorporated in the new methodologies for the synthesis of HIRCNs with and without heat of mixing. Various case studies are solved to illustrate the developed methodologies

Can oil prices predict the direction of exchange rate movements? An empirical and economic analysis for the case of India

This study investigates whether oil prices have enough predictive information to predict the direction of the movement of exchange rate by examining the type of cointegration relationship between exchange rate and oil prices in India between 1991Q1 and 2013Q1. Our findings suggest the existence of cointegration relationship between exchange rate and oil prices using both Engle–Granger two-step cointegration test and Johansen cointegration test. Using a momentum threshold autoregressive consistent model, we find evidence in favour of asymmetric cointegration between the two variables. Nevertheless we find no evidence to support asymmetric cointegration relationship between the two variables when threshold autoregressive, threshold autoregressive consistent, and momentum threshold autoregressive models are used. Thus, the results suggest that for certain time period, the adjustment process between exchange rate and oil price is constant, which makes it conducive for predicting the direction of exchange rate movement. However, evidence of asymmetric cointegration suggests that the stable relationship is likely to be interrupted with intervals of structural change implying correction in the dynamics of influencing factor

High-Efficiency Transduction of Primary Human Hematopoietic Stem/Progenitor Cells by AAV6 Vectors: Strategies for Overcoming Donor-Variation and Implications in Genome Editing.

We have reported that of the 10 commonly used AAV serotype vectors, AAV6 is the most efficient in transducing primary human hematopoietic stem/progenitor cells (HSPCs). However, the transduction efficiency of the wild-type (WT) AAV6 vector varies greatly in HSPCs from different donors. Here we report two distinct strategies to further increase the transduction efficiency in HSPCs from donors that are transduced less efficiently with the WT AAV6 vectors. The first strategy involved modifications of the viral capsid proteins where specific surface-exposed tyrosine (Y) and threonine (T) residues were mutagenized to generate a triple-mutant (Y705 + Y731F + T492V) AAV6 vector. The second strategy involved the use of ex vivo transduction at high cell density. The combined use of these strategies resulted in transduction efficiency exceeding ~90% in HSPCs at significantly reduced vector doses. Our studies have significant implications in the optimal use of capsid-optimized AAV6 vectors in genome editing in HSPCs

Consumer personality, privacy concerns and usage of location-based services (LBS)

This paper examines the effects of the Big Five personality traits on concern for information privacy (CFIP) and the effects of the formulated concern for information privacy towards perceived risk, which in turn determine location-based services (LBS) usage intention. Data for this research was collected from 291 users and non-users of LBS. Result from Pearson correlation analysis indicated significant relationships exist between: (1) extraversion, and openness with collection; (2) extraversion, conscientiousness, and openness with improper access; (3) extraversion, conscientiousness, and openness with errors; (4) agreeableness, neuroticism, and openness with secondary use. All four dimensions of CFIP are found to have a significant direct relationship with perceived risk of using LBS. Implications for research and practice for location-based service providers are discussed

Pluripotent human embryonic stem cell derived neural lineages for in vitro modelling of enterovirus 71 infection and therapy

The incidence of neurological complications and fatalities associated with Hand, Foot & Mouth disease has increased over recent years, due to emergence of newly-evolved strains of Enterovirus 71 (EV71). In the search for new antiviral therapeutics against EV71, accurate and sensitive in vitro cellular models for preliminary studies of EV71 pathogenesis is an essential prerequisite, before progressing to expensive and time-consuming live animal studies and clinical trials. This study thus investigated whether neural lineages derived from pluripotent human embryonic stem cells (hESC) can fulfil this purpose. EV71 infection of hESC-derived neural stem cells (NSC) and mature neurons (MN) was carried out in vitro, in comparison with RD and SH-SY5Y cell lines. Results: Upon assessment of post-infection survivability and EV71 production by the various types, it was observed that NSC were significantly more susceptible to EV71 infection compared to MN, RD (rhabdomyosarcoma) and SHSY5Y cells, which was consistent with previous studies on mice. The SP81 peptide had significantly greater inhibitory effect on EV71 production by NSC and MN compared to the cancer-derived RD and SH-SY5Y cell lines. Hence, this study demonstrates that hESC-derived neural lineages can be utilized as in vitro models for studying EV71 pathogenesis and for screening of antiviral therapeutics

Japanese Encephalitis, Singapore

10.3201/eid1203.051251Emerging Infectious Diseases123525-52

Potential of condensed tannins from Leucaena leucocephala hybrid on methane mitigation in ruminants

Methane is the second most important greenhouse gas that contributes to global warming and climate change. It has a heat trapping potential 23 times that of carbon dioxide. Globally, ruminant livestock produce about 80 million metric tonnes of enteric methane annually, accounting to about 30% of global anthropogenic methane production. Methane produced during enteric fermentation also contributes to a loss of energy of up to 15% for the animal. Thus, mitigation of methane production by ruminants not only reduces greenhouse gas emission but also improves feed efficiency and reduces production cost. There has been considerable interest in use of plant extracts to mitigate enteric ruminal methane emissions. Condensed tannins are secondary plant metabolites that have been considered for mitigating methane production in ruminants, but they may also decrease digestibility of feed in ruminants. Leucaena leucocephala is a tree legume that has been used as a feed supplement for ruminants because of its high protein content. However, it also contains condensed tannins. The L. leucocephala hybrids in Malaysia have been found to have higher condensed tannin contents than the parent L. leucocephala. The effectiveness of condensed tannins from these L. leucocephala hybrids on reduction of methane has not been studied. Thus, this study was conducted to investigate the effects of pure condensed tannins, extracted from young leaves and shoots of L. leucocephala hybrid-Rendang on methane mitigation, rumen fermentation parameters such as pH, dry matter (DM) digestibility, nitrogen degradability and volatile fatty acids production, as well as populations of methanogens and protozoa. The “in vitro gas production test” was used in the investigation as it provides data on fermentation parameters of feed with a high correlation to its in vivo base. The results showed that the condensed tannin extract, at a low level of 30 mg/g DM could reduce methane production by 39% as compared to the control, without negatively affecting DM digestibility, nitrogen degradability, rumen pH and total volatile fatty acids production. Total populations of methanogens and protozoa were also reduced by about 55 and 38%, respectively. Populations of methanogens in the orders Methanomicrobiales and Methanobacteriales were reduced by 22 and 7%, respectively. The findings of the study indicated that condensed tannins at 30 mg/g DM has the potential to be used as a feed supplement to reduce methane production in ruminants, without adversely affecting rumen fermentation parameters