The effect of hole localization on photocatalytic activity of Pt-tipped semiconductor nanocrystals is investigated. By tuning the energy balance at the semiconductor–ligand interface, we demonstrate ...that hydrogen production on Pt sites is efficient only when electron-donating molecules are used for stabilizing semiconductor surfaces. These surfactants play an important role in enabling an efficient and stable reduction of water by heterostructured nanocrystals as they fill vacancies in the valence band of the semiconductor domain, preventing its degradation. In particular, we show that the energy of oxidizing holes can be efficiently transferred to a ligand moiety, leaving the semiconductor domain intact. This allows reusing the inorganic portion of the “degraded” nanocrystal-ligand system simply by recharging these nanoparticles with fresh ligands.
Core/thick-shell giant quantum dots (gQDs) possessing type II electronic structures exhibit suppressed blinking and diminished nonradiative Auger recombination. We investigate CdSe/ZnSe and ZnSe/CdS ...as potential new gQDs. We show theoretically and experimentally that both can exhibit partial or complete spatial separation of an excited-state electron–hole pair (i.e., type II behavior). However, we reveal that thick-shell growth is challenged by competing processes: alloying and cation exchange. We demonstrate that these can be largely avoided by choice of shelling conditions (e.g., time, temperature, and QD core identity). The resulting CdSe/ZnSe gQDs exhibit unusual single-QD properties, principally emitting from dim gray states but having high two-exciton (biexciton) emission efficiencies, whereas ZnSe/CdS gQDs show characteristic gQD blinking suppression, though only if shelling is accompanied by partial cation exchange.
Despite being vaccine preventable, the global burden of dog rabies remains significant, and historically it is the rural and marginalized communities in developing countries of Africa and Asia that ...are most threatened by the disease. In recent years, the developing world has been experiencing unprecedented increases in urbanization, with a correspondingly massive increase in municipal solid waste generation, among other things. Inefficient and inadequate waste collection and management, due to lack of resources and planning, led to significant increases in the volumes of waste on the streets and in open dumps, where it serves as food sources for free-roaming dogs. In this commentary, we discuss examples of poor waste management and the likely impact on rabies control efforts through the sustenance of free-roaming dogs in some dog rabies-endemic countries. We aim to stress the importance of implementing strategies that effectively address this particular issue as an important component of humane dog population management, as it relates to aspirations for the control and elimination of dog rabies per se.
Antimicrobial Resistance in Nepal Acharya, Krishna Prasad; Wilson, R Trevor
Frontiers in medicine,
05/2019, Volume:
6
Journal Article
Peer reviewed
Open access
Antimicrobial resistance (AMR) is a global problem to animal and public health. It has drawn the attention of public health experts, stakeholders, and medical science due to the substantial economic ...loss that it causes to individuals and nation as a whole. Various cross-sectional studies and some national surveys in developing countries have shown increase in the burden of antimicrobial resistance. Nepal is one of the major contributors to the growing burden of AMR due to widespread irrational use of antibiotics along with poor health care systems poor infection control and prevention measures. This review was conducted to summarize the situation of AMR in Nepal, determinants of AMR, current government intervention strategies and the way forward to reduce the AMR burden in Nepal. Available cross sectional reports warn that bacterial pathogens are becoming highly resistant to most first- and some second-line antibiotics. The irrational and injudicious use of high doses of antibiotics for therapy and sub-optimal doses as growth promoters are leading causes of AMR in Nepal. Establishment of a surveillance programme and a national plan for containment of AMR, following the National Antibiotics Treatment Guideline 2014 and generation of awareness among veterinarians, technicians, and medical physicians on prudent use of antimicrobial drugs in Nepal could reduce the burden of AMR. In addition, there is a need to develop a national laboratory strategic plan to provide guidance and governance to national laboratories.
Injury and death from wildlife attacks often result in people feeling violent resentment and hostility against the wildlife involved and, therefore, may undermine public support for conservation. ...Although Nepal, with rich biodiversity, is doing well in its conservation efforts, human-wildlife conflicts have been a major challenge in recent years. The lack of detailed information on the spatial and temporal patterns of human-wildlife conflicts at the national level impedes the development of effective conflict mitigation plans. We examined patterns of human injury and death caused by large mammals using data from attack events and their spatiotemporal dimensions collected from a national survey of data available in Nepal over five years (2010-2014). Data were analyzed using logistic regression and chi-square or Fisher's exact tests. The results show that Asiatic elephants and common leopards are most commonly involved in attacks on people in terms of attack frequency and fatalities. Although one-horned rhinoceros and bears had a higher frequency of attacks than Bengal tigers, tigers caused more fatalities than each of these two species. Attacks by elephants peaked in winter and most frequently occurred outside protected areas in human settlements. Leopard attacks occurred almost entirely outside protected areas, and a significantly greater number of attacks occurred in human settlements. Attacks by one-horned rhinoceros and tigers were higher in the winter, mainly in forests inside protected areas; similarly, attacks by bears occurred mostly within protected areas. We found that human settlements are increasingly becoming conflict hotspots, with burgeoning incidents involving elephants and leopards. We conclude that species-specific conservation strategies are urgently needed, particularly for leopards and elephants. The implications of our findings for minimizing conflicts and conserving these imperiled species are discussed.
The nature of exciton−plasmon interactions in Au-tipped CdS nanorods has been investigated using femtosecond transient absorption spectroscopy. The study demonstrates that the key optoelectronic ...properties of composite heterostructures comprising electrically coupled metal and semiconductor domains are substantially different from those observed in systems with weak interdomain coupling. In particular, strongly coupled nanocomposites promote mixing of electronic states at semiconductor−metal domain interfaces, which causes a significant suppression of both plasmon and exciton excitations of carriers.
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