5,232 research outputs found
Seasonal and spatial dynamics of the primary vector of plasmodium knowlesi within a major transmission focus in Sabah, Malaysia
Background
The simian malaria parasite Plasmodium knowlesi is emerging as a public health problem in Southeast Asia, particularly in Malaysian Borneo where it now accounts for the greatest burden of malaria cases and deaths. Control is hindered by limited understanding of the ecology of potential vector species.
Methodology/Principal Findings
We conducted a one year longitudinal study of P. knowlesi vectors in three sites within an endemic area of Sabah, Malaysia. All mosquitoes were captured using human landing catch. Anopheles mosquitoes were dissected to determine, oocyst, sporozoites and parous rate. Anopheles balabacensis is confirmed as the primary vector of. P. knowlesi (using nested PCR) in Sabah for the first time. Vector densities were significantly higher and more seasonally variable in the village than forest or small scale farming site. However An. balabacensis survival and P. knowlesi infection rates were highest in forest and small scale farm sites. Anopheles balabacensis mostly bites humans outdoors in the early evening between 1800 to 2000hrs.
Conclusions/Significance
This study indicates transmission is unlikely to be prevented by bednets. This combined with its high vectorial capacity poses a threat to malaria elimination programmes within the region.
Author Summary
The first natural infection of Plasmodium knowlesi was reported 40 years ago. At that time it was perceived that the infection would not affect humans. However, now P. knowlesi is the predominant malaria species (38% of the cases) infecting people in Malaysia and is a notable obstacle to malaria elimination in the country. Plasmodium knowlesi has also been reported from all countries in Southeast Asia with the exception of Lao PDR and Timor Leste. In Sabah, Malaysian Borneo cases of human P. knowlesi are increasing. Thus, a comprehensive understanding of the bionomics of the vectors is required so as to enable proper control strategies. Here, we conducted a longitudinal study in Kudat district, Sabah, to determine and characterize the vectors of P. knowlesi within this transmission foci. Anopheles balabacensis was the predominant mosquito in all study sites and is confirmed as vector for P. knowlesi and other simian malaria parasites. The peak biting time was in the early part of the evening between1800 to 2000. Thus, breaking the chain of transmission is an extremely challenging task for the malaria elimination programme
Competitive Fixed-Bed Adsorption of Pb(II), Cu(II), and Ni(II) from Aqueous Solution Using Chitosan-Coated Bentonite
Distinct roles of NMB and GRP in itch transmission
A key question in our understanding of itch coding mechanisms is whether itch is relayed by dedicated molecular and neuronal pathways. Previous studies suggested that gastrin-releasing peptide (GRP) is an itch-specific neurotransmitter. Neuromedin B (NMB) is a mammalian member of the bombesin family of peptides closely related to GRP, but its role in itch is unclear. Here, we show that itch deficits in mice lacking NMB or GRP are non-redundant and Nmb/Grp double KO (DKO) mice displayed additive deficits. Furthermore, both Nmb/Grp and Nmbr/Grpr DKO mice responded normally to a wide array of noxious stimuli. Ablation of NMBR neurons partially attenuated peripherally induced itch without compromising nociceptive processing. Importantly, electrophysiological studies suggested that GRPR neurons receive glutamatergic input from NMBR neurons. Thus, we propose that NMB and GRP may transmit discrete itch information and NMBR neurons are an integral part of neural circuits for itch in the spinal cord
Two-dimensional amine and hydroxy functionalized fused aromatic covalent organic framework
Ordered two-dimensional covalent organic frameworks (COFs) have generally been synthesized using reversible reactions. It has been difficult to synthesize a similar degree of ordered COFs using irreversible reactions. Developing COFs with a fused aromatic ring system via an irreversible reaction is highly desirable but has remained a significant challenge. Here we demonstrate a COF that can be synthesized from organic building blocks via irreversible condensation (aromatization). The as-synthesized robust fused aromatic COF (F-COF) exhibits high crystallinity. Its lattice structure is characterized by scanning tunneling microscopy and X-ray diffraction pattern. Because of its fused aromatic ring system, the F-COF structure possesses high physiochemical stability, due to the absence of hydrolysable weak covalent bonds
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Importance of different parameterization changes for the updated dust cycle modeling in the Community Atmosphere Model (version 6.1)
The Community Atmosphere Model (CAM6.1), the atmospheric component of the Community Earth System Model (CESM; version 2.1), simulates the life cycle (emission, transport, and deposition) of mineral dust and its interactions with physio-chemical components to quantify the impacts of dust on climate and the Earth system. The accuracy of such quantifications relies on how well dust-related processes are represented in the model. Here we update the parameterizations for the dust module, including those on the dust emission scheme, the aerosol dry deposition scheme, the size distribution of transported dust, and the treatment of dust particle shape. Multiple simulations were undertaken to evaluate the model performance against diverse observations, and to understand how each update alters the modeled dust cycle and the simulated dust direct radiative effect. The model–observation comparisons suggest that substantially improved model representations of the dust cycle are achieved primarily through the new more physically-based dust emission scheme. In comparison, the other modifications induced small changes to the modeled dust cycle and model–observation comparisons, except the size distribution of dust in the coarse mode, which can be even more influential than that of replacing the dust emission scheme. We highlight which changes introduced here are important for which regions, shedding light on further dust model developments required for more accurately estimating interactions between dust and climate.</p
Holographic models for undoped Weyl semimetals
We continue our recently proposed holographic description of single-particle
correlation functions for four-dimensional chiral fermions with Lifshitz
scaling at zero chemical potential, paying particular attention to the
dynamical exponent z = 2. We present new results for the spectral densities and
dispersion relations at non-zero momenta and temperature. In contrast to the
relativistic case with z = 1, we find the existence of a quantum phase
transition from a non-Fermi liquid into a Fermi liquid in which two Fermi
surfaces spontaneously form, even at zero chemical potential. Our findings show
that the boundary system behaves like an undoped Weyl semimetal.Comment: 64 pages, 19 figure
Synthesis, Characterization and Electrochemical Analysis of V-Shaped Disubstituted Thiourea-Chlorophyll Thin Film as Active Layer in Organic Solar Cells
Conjugated thiourea system has attracted considerable attention as potential molecular framework to
construct molecular components for molecular electronics. To date, thiourea systems are surprisingly
unexplored although the well-known rigid π-systems enhance the development of molecular wire
architecture to be applied as potential organic solar cell (OSC). Regarding to this matter, a study on the
performance of conjugated V-shaped disubstituted thiourea compound systems to act as potential
active layer in OSC was carried out prior to form photovoltaic thin film. The compound namely
N
1
,N
3
-bis(4-(octyloxy)phenyl)-N-(benzene-1,3-dicarbonyl) thiourea was spectroscopically and
analytical characterized via Fourier Transform Infrared (FT-IR), UV-Visible Analysis (UV-Vis),
CHNS elemental analysis, 1H and 13C Nuclear Magnetic Resonance (NMR), Thermogravimetric
Analysis (TGA), Scanning Electron Microscopy (SEM) as well as Cyclic Voltammetry (CV) analysis.
In turn, it was fabricated on Indium Tin Oxide (ITO) substrate before its conductivity behaviour,
efficiency and OSC parameter were evaluated by Four Point Probe. From the electrical conductivity
study, it revealed that the layer of ITO/V-shaped thiourea thin film exhibits higher conductivity,
0.1377Scm-1 with the presence of chlorophyll (CHLO) under maximum light intensity of 100 Wm-2
.Therefore, further evaluation of this type of molecular framework featuring thiourea moiety should be
taken to enhance the development in the area of microelectronic devices
Automated quantification of mitral valve anatomy using anatomical intelligence in three-dimensional echocardiography
postprin
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