Fluorescent Receptors for Biomolecules

The development of synthetic receptors capable of high-affinity complexation of biologically relevant analytes in competitive solvent systems represents an ongoing challenge in molecular recognition. Anion recognition is particularly problematic, which is significant since numerous biological processes are regulated by anions, such as those resulting from phosphorylation. In this dissertation, we present the design and synthesis of a fluorescent sensor containing two cyclen groups that are preorganized to form a binding cleft for anion complexation. The receptor design includes a rigid acridine backbone, which is also exploited for fluorescence signal transduction. Furthermore, click chemistry is employed to facilitate receptor synthesis, and binding studies with various phosphorylated guest molecules are described. Additionally, the development of boronic acid-based carbohydrate receptors is presented. Carbohydrates play important roles in a large number of biochemical processes such as signal transduction and cell surface recognition events. The receptors will be used to study carbohydrate binding through Förster resonance energy transfer (FRET) and surface enhanced Raman spectroscopy (SERS). Another project involves the synthesis of aromatic compounds that can act as auxin herbicides. Auxins are plant hormones that play a major role in the regulation of plant growth and development. A modular synthetic strategy is employed to access a library of small molecules that will be tested for herbicidal activity on a variety of weeds. Finally, the work on the design and synthesis of molecular building blocks to generate covalently-bonded ordered organic frameworks is discussed

X-ray photoelectron spectroscopy of piperidinium ionic liquids: a comparison to the charge delocalised pyridinium analogues

In this study, nine piperidinium-based ionic liquids are analysed by X-ray photoelectron spectroscopy. The effect of alkyl substituent length and the nature of the anion on the electronic environment of the cation are investigated. The electronic environment of the hetero carbon and the cationic nitrogen is compared between two structurally similar cations, 1-octyl-1-methylpiperidinium ([C8C1Pip]+) versus 1-octylpyridinium ([C8Py]+). Due to the charge delocalisation, the hetero carbon component within [C8Py]+ is more positively charged, which exhibits much higher binding energy; whilst the cationic nitrogen component is in the similar electronic environment. The impact of the charge delocalisation on the electronic environment of the anion is also compared between [C8C1Pip]+ and [C8Py]+. It is found that for the more basic anion, the cation can significantly affect the electronic environment of the anion; for the less basic anion, such an effect concentrates on the component bearing more negative point charges

Fabrication and Magnetic Properties of Mn1 - xZnxFe2O4 (0 ≤ x ≤ 0.8) Nanoparticles

In this paper, we report results on the fabrication and magnetic properties of spinel ferrite Mn1-xZnxFe2O4 (0 ≤ x ≤ 0.8) nanoparticles. The nanoparticles were synthesized by a co-precipitation method. The effects of substituting Zn for Mn on the magnetic properties and particles size were focused. It was found that the phase-formation temperature is 90OC and the average particle size decreases from 40 nm to 10 nm when increased Zn concentration from zero to 0.8. The Curie temperature TC strongly decreases from 585 K (x = 0) to 320 K (x = 0.8) concomitantly with a decrease of the saturation magnetization MS. With a TC of 320 K and MS of 17 emu/g, the x=0.8 sample could be a promising candidate for some biomedical applications

Antibiotic Resistance Profile and Methicillin-Resistant Encoding Genes of Staphylococcus aureus Strains Isolated from Bloodstream Infection Patients in Northern Vietnam

Background:  Evaluating the antibiotic susceptibility and resistance genes is essential in the clinical management of bloodstream infections (BSIs). Nevertheless, there are still limited studies in Northern Vietnam. AIM: This study aimed to determine the antibiotic resistance profile and methicillin-resistant encoding genes of Staphylococcus aureus (S. aureus) causing BSIs in Northern Vietnam. METHODS: The cross-sectional study was done from December 2012 to June 2014 in two tertiary hospitals in Northern Vietnam. Tests performed at the lab of the hospital. RESULTS:  In 43 S. aureus strains isolating, 53.5 % were MRSA. Distribution of gene for overall, MRSA, and MSSA strains were following: mecA gene (58.1 %; 95.7%, and 15%), femA gene (48.8%, 47.8%, and 50%), femB gene (88.4%, 82.6%, and 95%). Antibiotic resistance was highest in penicillin (100%), followed by erythromycin (65.1%) and clindamycin (60.5%). Several antibiotics were susceptible (100%), including vancomycin, tigecycline, linezolid, quinupristin/dalfopristin. Quinolone group was highly sensitive, include ciprofloxacin (83.7%), levofloxacin (86%) and moxifloxacin (86%). CONCLUSION:  In S. aureus causing BSIs, antibiotic resistance was higher in penicillin, erythromycin, and clindamycin. All strains were utterly susceptible to vancomycin, tigecycline, linezolid, quinupristin/dalfopristin

Antibiotic Resistance Profile and Diversity of Subtypes Genes in Escherichia coli Causing Bloodstream Infection in Northern Vietnam

BACKGROUND: Evaluating the antibiotic susceptibility and resistance genes is essential in the clinical management of bloodstream infections (BSIs). But there are still limited studies in Northern Vietnam. AIM: The aim of the study was to determine the antibiotic resistance profile and characteristics of subtypes genes in Escherichia coli causing BSIs in Northern Vietnam. METHODS: The cross-sectional study was done in the period from December 2012 to June 2014 in two tertiary hospitals in Northern Vietnam. Tests were performed at the lab of the hospital. RESULTS: In 56 E. coli strains isolating 39.29 % produced ESBL. 100% of the isolates harbored blaTEM gene, but none of them had the blaPER gene. The prevalence of ESBL producers and ESBL non-producers in blaCTX-M gene was 81.82%, and 73.53%, in blaSHV gene was 18.18% and 35.29%. Sequencing results showed three blaTEM subtypes (blaTEM 1, 79, 82), four blaCTX-M subtypes (blaCTX-M-15, 73, 98, 161), and eight blaSHV subtypes (blaSHV 5, 7, 12, 15, 24, 33, 57, 77). Antibiotic resistance was higher in ampicillin (85.71%), trimethoprim/sulfamethoxazole (64.29%) and cephazolin (50%). Antibiotics were still highly susceptible including doripenem (96.43%), ertapenem (94.64%), amikacin (96.43%), and cefepime (89.29%). CONCLUSION: In Escherichia coli causing BSIs, antibiotic resistance was higher in ampicillin, trimethoprim/sulfamethoxazole and cephazolin. Antibiotics was highly susceptible including doripenem, ertapenem, amikacin, and cefepime

An update and reassessment of vascular plant species richness and distribution in Bach Ma National Park, Central Vietnam

Bach Ma National Park (BMNP) is recognized as an essential biodiversity hotspot in Vietnam because of its diverse topography, high species richness and threatened and endemic species. This study updates the richness and distribution of vascular plant species in the BMNP by intergrading data from literature, field surveys, key-informant interviews and participatory observations. Our results showed that the park has a high diversity of vascular plants with 1,874 species belonging to 192 families, 6 phylums including Psilotophyta, Lycopodiophyta, Equisetophyta, Polypodiophyta, Pinophyta, and Magnoliophyta. It also indicates that 199 out of 1,874 vascular species in the BMNP are listed as endangered, precious and rare plant species of Vietnam. In particular, 55 species are part of the IUCN 2020 list, in which 9 are critically endangered species (CR), 15 are endangered species (EN), and 31 are vulnerable species (VU). According to the rankings of the Red List Vietnam (2007), 6 species of CR (accounting for 13.64% compared with the whole country), 36 species of EN (20%), and 52 species of VU (26%) were found in this area. The results provided that vascular plant species are distributed into 2 types based on high altitude (threshold at 900m), but there are no dominant communities. The findings may be essential information for foresters and biologists to recognize and use it as the newest update for their next scientific research in conservation and resource management.Vườn Quốc gia (VQG) Bạch Mã được xem là một điểm nóng đa dạng sinh học quan trọng ở Việt Nam vì địa hình đa dạng, độ phong phú loài cao, đặc biệt là các loài đặc hữu và nguy cấp. Trong nghiên cứu này, chúng tôi đã cập nhật sự phong phú và phân bố của các loài thực vật bậc cao tại VQG Bạch Mã bằng cách kết hợp dữ liệu từ tổng quan tài liệu, khảo sát thực địa, phỏng vấn người am hiểu và điều tra có sự tham gia. Kết quả cho thấy VQG có hệ thực vật bậc cao phong phú với 1.874 loài, thuộc 192 họ, 6 ngành bao gồm Psilotophyta, Lycopodiophyta, Equisetophyta, Polypodiophyta, Pinophyta, Magnoliophyta. Kết quả chỉ ra rằng 199 trong số 1.874 loài thực vật bậc cao tại VQG này được xếp vào danh sách các loài nguy cấp của Việt Nam. Đặc biệt, có 55 loài thuộc danh mục của IUCN năm 2020, trong đó có 9 loài Cực kỳ nguy cấp (CR), 15 loài Nguy cấp (EN) và 31 loài Sẽ nguy cấp (VU). Trong khi đó, theo xếp hạng của Sách Đỏ Việt Nam (2007), nghiên cứu cho thấy có 6 loài CR (chiếm 13,64% so với cả nước), 36 loài EN (20%) và 52 loài VU (26%). Phát hiện của chúng tôi cũng chỉ ra rằng đặc điểm phân bố của các loài thực vật bậc cao ở VQG Bạch Mã gồm 2 kiểu rừng dựa trên độ cao (mức 900m), nhưng không có quần xã nào chiếm ưu thế. Các kết quả này được kỳ vọng sẽ là nguồn thông tin cần thiết cho các nhà hoạt động lâm nghiệp và sinh vật học sử dụng nó như một bản cập nhật mới nhất cho các nghiên cứu khoa học tiếp theo trong bảo tồn và quản lý tài nguyên

Effects of water scarcity awareness and climate change belief on recycled water usage willingness: Evidence from New Mexico, United States

The global water crisis is being exacerbated by climate change, even in the United States. Recycled water is a feasible alternative to alleviate the water shortage, but it is constrained by humans’ perceptions. The current study examines how residents’ water scarcity awareness and climate change belief influence their willingness to use recycled water directly and indirectly. Bayesian Mindsponge Framework (BMF) analytics was employed on a dataset of 1831 residents in Albuquerque, New Mexico, an arid inland region in the US. We discovered that residents’ willingness to use direct recycled potable water is positively affected by their awareness of water scarcity, but the effect is conditional on their belief in the impacts of climate change on the water cycle. Meanwhile, the willingness to use indirect recycled potable water is influenced by water scarcity awareness, and the belief in climate change further enhances this effect. These findings implicate that fighting climate change denialism and informing the public of the water scarcity situation in the region can contribute to the effectiveness and sustainability of long-term water conservation and climate change alleviation efforts

Spatiotemporal evolution of SARS-CoV-2 Alpha and Delta variants during large nationwide outbreak of COVID-19, Vietnam, 2021

We analyzed 1,303 SARS-CoV-2 whole-genome sequences from Vietnam, and found the Alpha and Delta variants were responsible for a large nationwide outbreak of COVID-19 in 2021. The Delta variant was confined to the AY.57 lineage and caused >1.7 million infections and >32,000 deaths. Viral transmission was strongly affected by nonpharmaceutical interventions

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

FTIR investigation of the interfacial properties and mechanisms of CO2 sorption in porous ionic liquids

Porous liquids, which are liquids with permanent porosity, have received significant attention as a new class of materials with the potential for far-reaching impacts in a variety of applications including gas separation. In this work, in situ Fourier transform infrared spectroscopy measurements were conducted to investigate the mechanism of carbon dioxide absorption in a porous ionic liquid consisting of ZIF-8 combined with 8,8′-(3,6-dioxaoctane-1,8-diyl)bis(1,8-diazabicyclo[5.4.0]undec-7-en-8-ium) bis(trifluoromethanesulfonyl)imide ([DBU-PEG][(Tf2N)2]). While the vibrational modes of the pure ionic liquid remain relatively unchanged, the incorporation of carbon dioxide leads to slight structural fluctuations in the ZIF-8 framework whether it is pure solid or as integrated into the porous ionic liquid. The analysis of the vibrational modes of the porous ionic liquid suggests that the interaction of the CO2 occurs more strongly with the ring structure of the ZIF-8 framework. The splitting of the asymmetric stretch of the CO2 into multiple peaks upon sorption indicate the presence of multiple environments, which could be a combination of free and physisorbed CO2 or simply multiple binding sites within the porous ionic liquid. A better understanding of gas sorption mechanisms in this unique material could lead to new porous ionic liquids with enhanced separations properties