274 research outputs found
Manipulation of photoluminescence of two-dimensional MoSe₂ by gold nanoantennas
Monolayer molybdenum diselenide (MoSe₂), a member of the TMDCs family, is an appealing candidate for coupling to gold plasmonic nanostructures as it has smaller bandgap and higher electron mobility in comparison to frequently studied molybdenum disulfide (MoS₂). The PL of MoSe₂ occurs in the near-infrared spectral range where the emissive properties do not suffer from the enhanced dissipation in the gold due to inter-band transitions. Here, we study the interaction between monolayer MoSe₂ and plasmonic dipolar antennas in resonance with the PL emission of MoSe₂. By varying the thickness of the spacer between the MoSe₂ layer and nanoantenna, we demonstrate manipulation of the PL intensity from nearly fourfold quenching to approximately threefold enhancement. Furthermore, we show that the coupled TMDC-nanoantenna system exhibits strong polarization-dependent PL, thus offering the possibility of polarization-based emission control. Our experimental results are supported by numerical simulations as well. To the best of our knowledge, this is the first study of Au-MoSe₂ plasmonic hybrid structures realizing flexible PL manipulation
Performance of rapid influenza H1N1 diagnostic tests: a meta-analysis: Accuracy of rapid H1N1 diagnostic tests
Following the outbreaks of 2009 pandemic H1N1 infection, rapid influenza diagnostic tests have been used to detect H1N1 infection. However, no meta-analysis has been undertaken to assess the diagnostic accuracy when this manuscript was drafted
Programmable and Multifunctional DNA-Based Materials for Biomedical Applications
DNA encodes the genetic information; recently, it has also become a key player in material science. Given the specific Watson–Crick base‐pairing interactions between only four types of nucleotides, well‐designed DNA self‐assembly can be programmable and predictable. Stem‐loops, sticky ends, Holliday junctions, DNA tiles, and lattices are typical motifs for forming DNA‐based structures. The oligonucleotides experience thermal annealing in a near‐neutral buffer containing a divalent cation (usually Mg2+) to produce a variety of DNA nanostructures. These structures not only show beautiful landscape, but can also be endowed with multifaceted functionalities. This Review begins with the fundamental characterization and evolutionary trajectory of DNA‐based artificial structures, but concentrates on their biomedical applications. The coverage spans from controlled drug delivery to high therapeutic profile and accurate diagnosis. A variety of DNA‐based materials, including aptamers, hydrogels, origamis, and tetrahedrons, are widely utilized in different biomedical fields. In addition, to achieve better performance and functionality, material hybridization is widely witnessed, and DNA nanostructure modification is also discussed. Although there are impressive advances and high expectations, the development of DNA‐based structures/technologies is still hindered by several commonly recognized challenges, such as nuclease instability, lack of pharmacokinetics data, and relatively high synthesis cost. </p
IsoDOT Detects Differential RNA-isoform Expression/Usage with respect to a Categorical or Continuous Covariate with High Sensitivity and Specificity
We have developed a statistical method named IsoDOT to assess differential
isoform expression (DIE) and differential isoform usage (DIU) using RNA-seq
data. Here isoform usage refers to relative isoform expression given the total
expression of the corresponding gene. IsoDOT performs two tasks that cannot be
accomplished by existing methods: to test DIE/DIU with respect to a continuous
covariate, and to test DIE/DIU for one case versus one control. The latter task
is not an uncommon situation in practice, e.g., comparing paternal and maternal
allele of one individual or comparing tumor and normal sample of one cancer
patient. Simulation studies demonstrate the high sensitivity and specificity of
IsoDOT. We apply IsoDOT to study the effects of haloperidol treatment on mouse
transcriptome and identify a group of genes whose isoform usages respond to
haloperidol treatment
Primary Study for the Therapeutic Dose and Time Window of Picroside II in Treating Cerebral Ischemic Injury in Rats
The aim of this study was to explore the optimal therapeutic dose and time window of picroside II for treating cerebral ischemic injury in rats according to the orthogonal test. The middle cerebral artery occlusion (MCAO) models were established by intraluminally inserting a thread into middle cerebral artery (MCA) from left external carotid artery (ECA). The successful rat models were randomly divided into 16 groups according to the orthogonal layout of [L16(45)] and treated by injecting picroside II intraperitoneally with different doses at various times. The neurological behavioral function was evaluated by Bederson’s test and the cerebral infarction volume was measured by tetrazolium chloride (TTC) staining. The expressions of neuron specific enolase (NSE) and neuroglial mark-protein S-100 were determined by immunohistochemisty assay. The results indicated that the optimal compositions of the therapeutic dose and time window of picroside II in treating cerebral ischemic injury were ischemia 1.5 h with 20 mg/kg body weight according to Bederson’s test, 1.0 h with 20 mg/kg body weight according to cerebral infarction volume, 1.5 h with 20 mg/kg body weight according to the expressions of NSE and S-100 respectively. Based on the principle of the minimization of medication dose and maximization of therapeutic time window, the optimal composition of the therapeutic dose and time window of picroside II in treating cerebral ischemic injury should be achieved by injecting picroside II intraperitoneally with 20 mg/kg body weight at ischemia 1.5 h
Design of Wide-Spectrum Inhibitors Targeting Coronavirus Main Proteases
The genus Coronavirus contains about 25 species of coronaviruses (CoVs), which are important pathogens causing highly prevalent diseases and often severe or fatal in humans and animals. No licensed specific drugs are available to prevent their infection. Different host receptors for cellular entry, poorly conserved structural proteins (antigens), and the high mutation and recombination rates of CoVs pose a significant problem in the development of wide-spectrum anti-CoV drugs and vaccines. CoV main proteases (M(pro)s), which are key enzymes in viral gene expression and replication, were revealed to share a highly conservative substrate-recognition pocket by comparison of four crystal structures and a homology model representing all three genetic clusters of the genus Coronavirus. This conclusion was further supported by enzyme activity assays. Mechanism-based irreversible inhibitors were designed, based on this conserved structural region, and a uniform inhibition mechanism was elucidated from the structures of M(pro)-inhibitor complexes from severe acute respiratory syndrome-CoV and porcine transmissible gastroenteritis virus. A structure-assisted optimization program has yielded compounds with fast in vitro inactivation of multiple CoV M(pro)s, potent antiviral activity, and extremely low cellular toxicity in cell-based assays. Further modification could rapidly lead to the discovery of a single agent with clinical potential against existing and possible future emerging CoV-related diseases
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Caspase polymorphisms and prognosis of hepatocellular carcinoma
The aim of our study was to determine the impact of genetic polymorphisms in the caspase (CASP) genes on prognosis of hepatocellular carcinoma (HCC). We genotyped 7 potentially functional polymorphisms in CASP3, CASP7, CASP8, CASP9, CASP10 genes in 362 HCC patients of receiving surgical resection of HCC tumor. The associations of genotype and haplotype with overall survival (OS) and disease free survival (DFS) were analyzed by using the Cox proportional hazards model. We found that the CASP9 rs4645981 C allele was significantly associated with positive effect on DFS (P = 0.011 and 0.016 for CT+CC vs. TT in univariate and multivariate analysis, respectively), CT genotype was associated with a better OS of HCC than the TT genotype both in univariate and multivariate analysis (P = 0.048 and 0.041, respectively). Moreover, the CASP3 rs2705897 GT genotype showed marginally significant association with decreased OS and DFS, compared with the GG genotype. One haplotype TT/TG in CASP3 (constructed by rs12108497 T>C and rs2705897 T>G) was significantly associated with decreased OS and DFS, compared to the common haplotype TT/TT both in univariate analysis (P = 0.021 and 0.026, respectively) and multivariate analysis (P = 0.025 and 0.030, respectively). The haplotype GT/GT in CASP9 (constructed by rs4645978 A>G and rs4645981 C>T) was significantly associated with decreased DFS both in univariate and multivariate analysis (P = 0.012 and 0.010, respectively). In conclusion, the CASP9 rs4645981 polymorphism, CASP3 and CASP9 haplotypes may be useful prognosis markers for HCC patients with surgical resection of tumor
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