Publications by authors named "Khoa D"

We report an experimental measurement of giant group index in the Rb atomic medium at room temperature via a four-level V-type scheme on the D line. Our experiment uses co-propagation configuration of probe and coupling lasers through an atomic sample. In this configuration, three sharp EIT windows with significant transparency depths are observed on the probe absorption spectrum.

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In this paper, we study the formation of optical bistability (OB) and optical multistability (OM) in a degenerate four-level atomic system by an external magnetic field that is excited by a probe laser field, a coupling laser field and a signal laser field. The coupling field can cause electromagnetically induced transparency (EIT) for the probe field in the atomic medium, while the signal field and/or external magnetic field can switch between single-EIT and two-EIT regimes. Based on these properties, OB and OM effects can be formed at two different frequency regions of the probe field (two channels).

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Patients with severe COVID-19 disease require monitoring with pulse oximetry as a minimal requirement. In many low- and middle- income countries, this has been challenging due to lack of staff and equipment. Wearable pulse oximeters potentially offer an attractive means to address this need, due to their low cost, battery operability and capacity for remote monitoring.

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Background: Chronic limb-threatening ischemia (CLTI) is the most severe clinical form of peripheral artery disease (PAD), accounting for approximately 11%, and is strongly associated with the incidence of amputation, cardiovascular events, and mortality. The Global Vascular Guideline (GVG) proposed a new Global Anatomic Staging System (GLASS) for evaluating the anatomic complexity of arterial lesions. However, more research is required to evaluate outcomes after endovascular intervention in CLTI patients using the GLASS.

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Idiopathic pulmonary fibrosis (IPF) is a severe and progressive chronic fibrosing interstitial lung disease with causes that have remained unclear to date. Development of effective treatments will require elucidation of the detailed pathogenetic mechanisms of IPF at both the molecular and cellular levels. With a biomedical corpus that includes IPF-related entities and events, text-mining systems can efficiently extract such mechanism-related information from huge amounts of literature on the disease.

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We studied the development and persistence of neutralizing antibodies against SARS-CoV-2 ancestral strain, and Delta and Omicron (BA.1 and BA.2) variants in Vietnamese healthcare workers (HCWs) up to 15 weeks after booster vaccination.

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Objectives: This study aimed to compare the efficacy and the safety of ultrasound-guided continuous thoracic paravertebral block (CTPB) to the continuous thoracic epidural block (CTEB) for pain relief in patients undergoing lung surgery.

Material And Methods: Our study included 102 patients after lung surgery at the 74 Central Hospital from 9/2013 to 12/2017. Patients were divided into 2 groups: CTPB group (n= 51) and CTEB group (n= 51).

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Background: Data on breakthrough SARS-CoV-2 Delta variant infections in vaccinated individuals are limited.

Methods: We studied breakthrough infections among Oxford-AstraZeneca vaccinated healthcare workers in an infectious diseases hospital in Vietnam. We collected demographic and clinical data alongside serial PCR testing, measurement of SARS-CoV-2 antibodies, and viral whole-genome sequencing.

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Raw or undercooked fish dishes are the major sources of human infection of fishborne trematodes (FBT) and the situation of metacercarial infection in fish greatly affect the prevalence in humans, especially those fish that are commonly used for raw consumption. To investigate the situation of infection with metacercaria of FBT in fish often used to prepare raw fish dishes by local people to assess the risk of infection to humans in Ninh Binh province, Vietnam. 345 fish belonging to five species of freshwater and one species of brackish water fish were collected from fishermen or small-scale fish dealers in Kim Son and Yen Khanh districts, Ninh Binh province between May 2017 and May 2018.

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Due to the coexistence of Dirac and triplet fermions, monolayer β12-borophene has recently attracted both experimental and theoretical researchers. In particular, various phase transitions have been recently reported in the structure, in the presence of dilute charged impurity and a perpendicular electric field, leading to interesting electronic heat capacity (HC). In this paper, we systematically examine the effects of charged impurity doping and electric field on the HC of monolayer β12-borophene.

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Article Synopsis
  • Ungulate protoparvovirus 1 (PPV1) is a leading cause of reproductive issues in pig farms, with several other related parvoviruses (PPV2, PPV3, PPV4) also identified but less studied in pigs.
  • A study tested 231 lung and serum samples from slaughterhouses in Vietnam, finding a prevalence of 54.5% for PPV1, 28.0% for PPV2, 17.7% for PPV3, and 7.8% for PPV4, with co-infections primarily involving PPV1 and PPV2.
  • The research documented nearly complete genomic sequences of PPV4, revealing high genetic similarity
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Injectable interferon-based therapies have been used to treat hepatitis C virus (HCV) infection since 1991. International guidelines have now moved away from interferon-based therapy towards direct-acting antiviral (DAA) tablet regimens, because of their superior efficacy, excellent side-effect profiles, and ease of administration. Initially DAA drugs were prohibitively expensive for most healthcare systems.

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To assess the effectiveness of extra-curricular activities in improving reproductive health knowledge of ethnic minority students in mountainous areas in Vietnam. The study was conducted on 400 ethnic minority students at Dien Bien Dong Ethnic Minority High School in Vietnam. The selected healthy students with a similar mix of study results and grades were divided into two groups: a control group had no the extra-curricular activities on reproductive health, and an experimental group participated extra-curricular activities on reproductive health.

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In this paper, the potential of engineering and manipulating the electronic heat capacity and Pauli susceptibility of pristine and perturbed hydrogenated AA-stacked graphene, SiC (silicon carbide), and h-BN (hexagonal boron nitride) bilayers is studied using a designed transverse Zeeman magnetic field and the dilute charged impurity. The tight-binding Hamiltonian model, the Born approximation and the Green's function method describe the carrier dynamics up to a certain degree. The unperturbed results show that the heat capacity and susceptibility of all bilayers increase with different hydrogenation doping configurations.

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β12-Borophene is a perfect planar nanolattice comprising of massless Dirac fermions and massless/massive triplet fermions considering the inversion symmetry lattice model. In this paper, a detailed study of the electric field and the effects of low concentrations of impurities on the electronic phase and the electrical conductivity of β12-borophene is presented. As a direct manner to judge the electronic features of pristine and perturbed monolayer β12-borophene, the five-band tight-binding Hamiltonian model, the T-matrix theory, the linear response theory, and the Green's function approach are investigated.

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Optical activity is one of the most fascinating fields in current physics. The strong anisotropic feature in monolayer phosphorene leads to the emergence of non-trivial optoelectronic physics. This paper is devoted to a detailed analysis of strain effects on the optical activity of phosphorene ranging from low-optical-field to high-optical-field.

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The brown planthopper (BPH), Nilaparvata lugens, is a serious threat to rice production in Vietnam and insecticides are widely used for its control. Migration of the BPH have one of its roots in tropical Vietnam in the Mekong River Delta and the insecticide resistance status of BPH populations from Vietnam is thus important for East Asia. In the present investigation, we evaluate the susceptibility of BPH populations from nine provinces from the Red River Delta, the Central Coastal region and the Mekong River Delta of eight insecticides during 2015-17.

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The complement system is a part of the natural immune regulation mechanism against invading pathogens. Complement activation from three different pathways (classical, lectin, and alternative) leads to the formation of C5-convertase, an enzyme for cleavage of C5 into C5a and C5b, followed by C6, C7, C8, and C9 in membrane attack complex. The C9 is the last complement component of the terminal lytic pathway, which plays an important role in lysis of the target cells depending on its self-polymerization to form transmembrane channels.

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Article Synopsis
  • PRRSV is a significant swine virus in Vietnam causing economic losses by reducing pig productivity, and this study analyzed 32 PRRSV isolates collected from 2008-2012.
  • The sequencing of the major envelope protein encoding gene (ORF5) revealed high genetic similarity among the isolates (94.8-100% nucleotide identity), particularly with North American and some Chinese strains.
  • Phylogenetic analysis classified the isolates into the North American genotype, specifically sub-lineage 8.7, which includes highly pathogenic strains, indicating the need for updated PRRS vaccine strategies in Vietnam.
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We cloned a cDNA encoding inhibitor of apoptosis (IAP) from the greater wax moth, Galleria mellonella. The deduced amino acid sequence showed that GmIAP contains two baculoviral IAP repeat (BIR) motifs, followed by a RING finger. The sequence comparison showed that GmIAP had high homology to lepidopteran IAPs and baculoviral IAPs, as well as dipteran IAPs.

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A 345 base pair cDNA encoding autophagy 8 (Atg8) of Galleria mellonella (GmAtg8) was cloned and sequenced. The deduced protein was estimated to be 118 amino acids long. Structural comparison and phylogenetic analysis showed that GmAtg8 belong to the Atg8 family of ubiquitin-like proteins.

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The cDNA encoding caspase-1, a main protease involved in apoptosis, was cloned and sequenced from the midgut of the greater wax moth, Galleria mellonella. The open reading frame contains 879 nucleotides, encodes 293 amino acids, and was registered as Gmcaspase-1. The sequence comparison showed a high homology to lepidopteran caspase-1, human caspase-3, and ced-3 of Caenorhabditis elegans.

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Background: The complement system is an evolutionary ancient mechanism that plays an essential role in innate immunity and contributes to the acquired immune response. Three modes of activation, known as classical, alternative and lectin pathway, lead to the initiation of a common terminal lytic pathway. The terminal complement components (TCCs: C6, C7, C8A, C8B, and C9) are encoded by the genes C6, C7, C8A, C8B, C8G, and C9.

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In order to obtain an approximate assessment of the public health burden that will be posed by the inherited disorders of haemoglobin in southern Vietnam, several thousand individuals were screened for these conditions. A smaller sample was screened for glucose-6-phosphate dehydrogenase (G6PD) deficiency. The important haemoglobin disorders identified were beta thalassaemia, haemoglobin E and a variety of different forms of alpha thalassaemia.

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Objective: Adenosine regulates inflammation and tissue repair, and adenosine A2A receptors promote wound healing by stimulating collagen matrix production. We therefore examined whether adenosine A2A receptors contribute to the pathogenesis of dermal fibrosis.

Methods: Collagen production by primary human dermal fibroblasts was analyzed by real-time polymerase chain reaction, 14C-proline incorporation, and Sircol assay.

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