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1.
Heliyon ; 9(11): e22450, 2023 Nov.
Article in English | MEDLINE | ID: mdl-38034627

ABSTRACT

In Vietnamese culture, bamboo holds deep symbolic significance. However, in recent years, as a result of evolving usage patterns and the introduction of alternative materials in the face of a rapidly developing modern market economy, industrialisation, and urbanisation, bamboo's economic and social value has dwindled. Nevertheless, with the pressing challenges of climate change, environmental pollution, and the depletion of natural resources, bamboo is experiencing a resurgence in importance within the lives of Vietnamese people. Ba Be district, situated in Bac Kan province, stands as one of the country's most impoverished regions. Natural bamboo thrives in 14 out of 15 communes, with Dong Phuc commune being the exception. Planted bamboo is found in 14 out of 15 communes, excluding Cho Ra town, covering approximately 7.9 % of the entire district's natural area (NA). The district's vast terrain, featuring slopes exceeding 15°, presents formidable obstacles to socio-economic development. This study aims to shed light on the distribution of bamboo forests in Ba Be district and presents an assessment of bamboo's suitability within its natural surroundings. The study employs the analytical hierarchy process (AHP) method and spatial statistics, using remote sensing data supplied by the Department of Natural Resources and Environment, Ba Be district. The results demonstrate that 60 % of Ba Be district's NA is conducive to bamboo cultivation and growth. The findings of this research provide local authorities with a scientifically grounded basis for strategic planning, enabling bamboo to emerge as a pivotal resource within production forests. This approach outlines the ideal spatial distribution for bamboo cultivation and development, ultimately fostering the sustainable utilisation of local natural resources to support both immediate and long-term local socio-economic development.

2.
Chemistry ; 27(36): 9198-9217, 2021 Jun 25.
Article in English | MEDLINE | ID: mdl-33792101

ABSTRACT

Magnesium batteries, like lithium-ion batteries, with higher abundance and similar efficiency, have drawn great interest for large-scale applications such as electric vehicles, grid energy storage and many more. On the other hand, the use of organic electrode materials allows high energy-performance, metal-free, environmentally friendly, versatile, lightweight, and economically efficient magnesium storage devices. In particular, the structural diversity and the simple activity of organic molecules make redox properties, and hence battery efficiency, easy to monitor. While organic magnesium batteries still in their infancy, this field becomes more and more promising because significant results were reported. To summarize the achievements in studies on organic cathodes for magnesium systems, their synthesis is discussed, combined with electrode design to provide the basis for controlling the electrochemical properties. Moreover, the techniques to synthesize organic materials with high-yield are mentioned. Finally, potential problems and prospects are explored to further improve organic cathodes.

3.
J Virol Methods ; 277: 113801, 2020 03.
Article in English | MEDLINE | ID: mdl-31838003

ABSTRACT

Seasonal influenza virus causes acute respiratory tract infections, which can be severe in children and the elderly. At present, rapid influenza diagnostic tests (RIDTs) are popular at clinical sites because they enable early diagnosis and avoid unnecessary use of antibiotics; in addition, high risk patients with underlying disease can be given antiviral drugs. However, the sensitivity and specificity of some of those tests are relatively poor. To overcome these problems, nucleic acid-based molecular point-of-care tests have been developed; however, they are significantly more expensive than RIDTs. Previously, the authors developed real-time reverse transcription loop-mediated isothermal amplification (rRT-LAMP) assays using a quenching primer to detect influenza viruses. However, the assay is limited to laboratory use because it requires a nucleic acid purification step and preparation of reaction mixtures on ice. Therefore, the authors developed and validated direct rRT-LAMP assays that require no nucleic acid purification steps using commercial RNA isolation kits, and no storage and handling of reagents on ice. These assays can be performed within 10-30 min and require only mixing a clinical specimen with extraction reagent followed by addition of a lyophilized detection reagent. The established assay showed high sensitivity and specificity when validated using 310 clinical specimens. Thus, the assay is a powerful tool for molecular diagnosis of seasonal influenza virus infection in the clinic.


Subject(s)
Influenza, Human/diagnosis , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methods , Reverse Transcription , Adolescent , Adult , Aged , Aged, 80 and over , DNA Primers/genetics , Female , Fluorescence , Humans , Influenza, Human/virology , Male , Middle Aged , Molecular Diagnostic Techniques/standards , RNA, Viral/genetics , Respiratory Tract Infections/virology , Sensitivity and Specificity , Young Adult
4.
Environ Sci Technol ; 46(24): 13184-92, 2012 Dec 18.
Article in English | MEDLINE | ID: mdl-23214945

ABSTRACT

Understanding the effects of chlorine exposure on polyamide (PA) based membranes is essential in membrane lifespan improvement. In this study, NF90 nanofiltration membrane was treated with sodium hypochlorite at different concentrations, pHs and durations. The changes in membrane elemental composition and bonding chemistry obtained from XPS and ATR-FTIR revealed the impacts of two competing mechanisms: N-chlorination and chlorination-promoted hydrolysis. More chlorine was incorporated into the PA matrix at pH <7, at which HOCl is dominant, while chlorine-promoted hydrolysis was more favorable at pH >7 with abundant hydroxyl groups. The membrane surface became more hydrophobic when chlorination was dominant, which in turn caused the water permeability of chlorinated membrane to decrease. Meanwhile, membrane became more hydrophilic and less cross-linked when hydrolysis effects were governing, which made the membrane more permeable for water. Rejection of charged solutes [NaCl, As(V)] improved in most chlorinating conditions due to increased charge density. However, when hydrolysis was severe (≥ 1000 ppm, pH 7 and 9), the enhanced charge repulsion effect could not compensate for the extensive amide bond cleavage, resulting in declined rejection. The lower rejection of neutral boric acid provided strong evidence of a less cross-linked separation layer.


Subject(s)
Chemical Phenomena , Chlorine/chemistry , Membranes, Artificial , Nylons/chemistry , Calcium/chemistry , Cations , Filtration , Halogenation , Hydrogen-Ion Concentration , Hydrolysis , Nanotechnology , Nitrogen/analysis , Oxygen/analysis , Permeability , Sodium Chloride/chemistry , Spectroscopy, Fourier Transform Infrared , Surface Properties , Time Factors , Water/chemistry , Water Pollutants, Chemical/analysis
5.
Water Res ; 46(16): 5217-23, 2012 Oct 15.
Article in English | MEDLINE | ID: mdl-22818949

ABSTRACT

The separation layer of polyamide-based (PA) thin film composite (TFC) membranes can be modified by active chlorine species. The PA-TFC membranes, NF90, BW30 and NF270, were exposed to different concentrations of sodium hypochlorite (NaOCl) at pH 5 for 24 h. Elemental composition obtained from X-ray Photoelectron Spectroscopy (XPS) showed that the chlorine content in the PA layer increased with the chlorine concentrations. Treatment of membranes with 10 ppm Cl increased the membrane hydrophilicity. By contrast, when treated with 1000 ppm Cl or more, the membranes became less hydrophilic. Water permeability values for all 3 membrane types declined with increased chlorine concentrations. Filtration of polyethylene glycols (PEGs) with molecular weights of 200, 400 and 600 Daltons (Da) was performed to investigate the influence of chlorine treatment on membrane molecular weight cut off (MWCO) and rejection by size exclusion. Treatment with 10 and 100 ppm Cl lowered the MWCO while treatment with higher concentrations increased the MWCO. All chlorinated membranes experienced higher NaCl rejection compared to virgin ones. The performance of NF90 was tested with respect to the rejection of inorganic contaminants including boron (H(3)BO(3)) and arsenic (H(2)AsO(4)(-)). The boron rejection results paralleled PEG rejection whereas those for arsenic followed NaCl rejection patterns. The changes in membrane performance due to chlorine treatment were explained in terms of competing mechanisms: membrane tightening, bond cleavage by N-chlorination and chlorination promoted polyamide hydrolysis.


Subject(s)
Arsenic/analysis , Boron/analysis , Filtration/methods , Hypochlorous Acid/chemistry , Membranes, Artificial , Nanostructures , Polyethylene Glycols/analysis , Chlorine/analysis , Filtration/instrumentation , Hydrolysis , Nylons , Photoelectron Spectroscopy
6.
Environ Sci Technol ; 46(2): 852-9, 2012 Jan 17.
Article in English | MEDLINE | ID: mdl-22221176

ABSTRACT

The degradation of polyamide (PA) nanofiltration and reverse osmosis membranes by chlorine needs to be understood in order to develop chlorine-resistant membranes. Coated and uncoated fully aromatic (FA) and piperazine (PIP) semi-aromatic PA membranes were treated with hypochlorite solution and analyzed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR). XPS results showed that in chlorine treated FA PA membranes the ratio of bound chlorine to surface nitrogen was 1:1 whereas it was only 1:6 in the case of PIP PA membranes. Surface oxygen of uncoated FA and PIP membranes increased with increasing hypochlorite concentration whereas it decreased for coated FA membranes. High resolution XPS data support that chlorination increased the number of carboxylic groups on the PA surface, which appear to form by hydrolysis of the amide bonds (C(O)-N). FTIR data indicated the disappearance of the amide II band (1541 cm(-1)) and aromatic amide peak (1609 cm(-1)) in both coated and uncoated chlorinated FA membranes, consistent with the N-chlorination suggested by the XPS results. Furthermore, the surface charge of chlorinated membranes at low pH (<6) became negative, consistent with amide-nitrogen chlorination. Chlorination appeared to both increase and decrease membrane hydrophobicity depending on chlorination exposure conditions, which implied that N-chlorination and hydrolysis may be competing processes. The effects of property changes on the membrane performance were also observed for NF90, BW30, and NF270 membranes.


Subject(s)
Filtration/instrumentation , Hypochlorous Acid/chemistry , Membranes, Artificial , Nanostructures/chemistry , Nylons/chemistry , Filtration/methods , Molecular Structure , Osmosis
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