Interaction between triphenylphosphine or 1,2-bis(diphenylphosphino)ethane with some complexes K[PtCl3(olefin)] (olefin: methyleugenol, safrole, isopropyl eugenoxyacetate)

Novel study on the interaction between K[PtCl3(olefin)] (olefin: methyleugenol, safrole and isopropyl eugenoxyacetate) with TPP and DPPE shows that TPP and DPPE readily replace the olefins to form complexes [PtCl2(TPP)2] (P4), [PtCl2(DPPE)] (P5) and [Pt(DPPE)2]Cl2 (P6). P4 possesses trans configuration when the molar ratio of the mono olefin and TPP of 1:1. When the ratio is 1:2, P4 is a mixture of trans and cis isomers of which trans one is prevailing. The cis isomer trends to convert to trans one in chloroform solvent. P5 and P6 were formed when the molar ratio of mono isopropyl eugenoxyacetate and DPPE of 1:1 and 1:2, respectively. The structures of P4÷P6 were elucidated by Pt analysis, ESI-MS, IR and 1H NMR spectra studies. Keywords. Pt(II) complexes, olefins, phosphine derivatives

Phase Shift Design for RIS-Aided Cell-Free Massive MIMO with Improved Differential Evolution

This paper proposes a novel phase shift design for cell-free massive multiple-input and multiple-output (MIMO) systems assisted by reconfigurable intelligent surface (RIS), which only utilizes channel statistics to achieve the uplink sum ergodic throughput maximization under spatial channel correlations. Due to the non-convexity and the scale of the derived optimization problem, we develop an improved version of the differential evolution (DE) algorithm. The proposed scheme is capable of providing high-quality solutions within reasonable computing time. Numerical results demonstrate superior improvements of the proposed phase shift designs over the other benchmarks, particularly in scenarios where direct links are highly probable.Comment: 5 pages, 2 figures. Accepted by IEEE WC

The effect of polyamine 70000 (BT70) on the zinc plating process in the non-cyanide alkaline plating bath

The effect of polyamine having molecular weight 70,000u (BT70) in the non-cyanide alkaline plating bath on the morphological zinc electrodeposited coating was investigated. The obtained results from the reflectance of electrodeposited zinc coating by a suitable range of electro-current density and SEM images showed that BT70 had effect on the zinc plating in comparison with the zinc deposits from plating bath without BT70. The electrodeposited coating surface was rough and poor adhesion. However, adding BT70 into the plating bath led to the surface roughness of electrodeposited coating and grand size being reduced. Zinc electrodeposited coating from a plating bath containing BT70 at 0.5 g/L, respectively, experienced the highest reflectance, equal 46 % of the electrodeposited coating from the bath containing commercial additives. Hull method showed that the zinc deposited coating surface became smoother with the presence of polyamine in non-cyanide alkaline zinc plating solution. The zinc deposited coating had a semi-gloss scope at 10 A/dm2. If the BT70 content increased, the semi-gloss scop and the gloss of samples’ surfaces also grew up. Keywords. Polyamine, additive, non-cyanide alkaline zinc plating, zinc coating

The results of deep magnetotelluric sounding for studying the Nha Trang - Tanh Linh fault

The profile of deep magnetotelluric sounding (MT) from Duc Trong - Tuy Phong has been carried out in Lam Dong and Binh Thuan  provinces. The length of the Duc Trong - Tuy Phong profile is about 80 km with 15 stations and the distance between the stations measures about 5 km. Two-dimensional MT inversion was used to find a resistivity model that fits the data. The 2D resistivity model allows determining position and development formation of the Nha Trang - Tanh Linh  fault. This is the deep fault, which is showed by the boundaries of remarkable change of resistivity. In the near surface of the Earth (from ground to the depth of 6 km), the angle of inclination of this fault is about 60o; in the next part, the direction of the Nha Trang - Tanh Linh  faut is vertical. Geoelectrical section of the Nha Trang - Tanh Linh  profile shows that the resistivity of mid-crust is higher than that of lower-crust and of upper-crust

In vitro antioxidant activity and bioactive compounds from Calocybe indica

Nowadays, the use of mushrooms in medicine is ubiquitous and has achieved particular success. The antioxidants in mushrooms can deactivate free radicals. This study assesses the antioxidant potential of mushroom Calocybe indica with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging methods and the total antioxidant capacity. The mushroom’s ethanol extract exhibits acceptable activity with a low IC50 value (240.11 μg/mL), approximately 2.9 times lower than that of the mushroom Ophiocordyceps sobolifera extract. The ABTS scavenging rate of the extract is around 60% at 500 µg/mL, and the total antioxidant capacity is equivalent to 64.94 ± 1.03 mg of GA/g or 77.42 ± 0.42 μmol of AS/g.  The total phenolics, flavonoids, polysaccharides, and triterpenoids are equivalent to 29.33 ± 0.16 mg of GAE/g, 17.84 ± 0.11 mg of QUE/g (5.04 ± 0.04%), and 4.96 ± 0.04 mg of oleanolic acid/g, respectively. Specifically, the total triterpenoid content has been reported for the first time. The mushroom can have potential biomedical applications

A global analysis of COVID-19 infection fatality rate and its associated factors during the Delta and Omicron variant periods: an ecological study

BackgroundThe Omicron variant of SARS-CoV-2 is more highly infectious and transmissible than prior variants of concern. It was unclear which factors might have contributed to the alteration of COVID-19 cases and deaths during the Delta and Omicron variant periods. This study aimed to compare the COVID-19 average weekly infection fatality rate (AWIFR), investigate factors associated with COVID-19 AWIFR, and explore the factors linked to the increase in COVID-19 AWIFR between two periods of Delta and Omicron variants.Materials and methodsAn ecological study has been conducted among 110 countries over the first 12 weeks during two periods of Delta and Omicron variant dominance using open publicly available datasets. Our analysis included 102 countries in the Delta period and 107 countries in the Omicron period. Linear mixed-effects models and linear regression models were used to explore factors associated with the variation of AWIFR over Delta and Omicron periods.FindingsDuring the Delta period, the lower AWIFR was witnessed in countries with better government effectiveness index [β = −0.762, 95% CI (−1.238)–(−0.287)] and higher proportion of the people fully vaccinated [β = −0.385, 95% CI (−0.629)–(−0.141)]. In contrast, a higher burden of cardiovascular diseases was positively associated with AWIFR (β = 0.517, 95% CI 0.102–0.932). Over the Omicron period, while years lived with disability (YLD) caused by metabolism disorders (β = 0.843, 95% CI 0.486–1.2), the proportion of the population aged older than 65 years (β = 0.737, 95% CI 0.237–1.238) was positively associated with poorer AWIFR, and the high proportion of the population vaccinated with a booster dose [β = −0.321, 95% CI (−0.624)–(−0.018)] was linked with the better outcome. Over two periods of Delta and Omicron, the increase in government effectiveness index was associated with a decrease in AWIFR [β = −0.438, 95% CI (−0.750)–(−0.126)]; whereas, higher death rates caused by diabetes and kidney (β = 0.472, 95% CI 0.089–0.855) and percentage of population aged older than 65 years (β = 0.407, 95% CI 0.013–0.802) were associated with a significant increase in AWIFR.ConclusionThe COVID-19 infection fatality rates were strongly linked with the coverage of vaccination rate, effectiveness of government, and health burden related to chronic diseases. Therefore, proper policies for the improvement of vaccination coverage and support of vulnerable groups could substantially mitigate the burden of COVID-19

LIGNANS FROM LEAVES OF AMESIODENDRON CHINENSE AND THEIR CYTOTOXIC ACTIVITY

ABSTRACTFrom leaves of Amesiodendron chinense (Mer.) Hu four lignans (+)-aptosimon (1), (+)-isolariciresinol (2), (-)-cleomiscosin A (3), and (-)-cleomiscosin C (3) were isolated. Their structures were determined by spectroscopic analysis including MS, 1D and 2D NMR as well as by comparison with reported data in literature. All compounds were evaluated for cytotoxic activities against five human cancer cell lines, KB, SK-LU-1, MCF-7, HepG-2, and SW-480. They showed weak cytotoxic activity on five tested human cancer cell lines with IC50 values ranging from 32.61 to 95.18 µg/ml

NGHIÊN CỨU CẤU TRÚC SÂU KHU VỰC ĐỨT GÃY SÔNG SÀI GÒN BẰNG PHƯƠNG PHÁP TỪ TELUA

This paper presents the magnetotelluric sounding results  of  Cu  Chi  -  Ben  Cat profile across the  Saigon  River fault. Results obtained by one-dimensional inversion of the data of a typical station located near the middle of the profile show that the geoelectric structure of the study area consists of three layers, in which the resistivities of the superficial and the underlying layers are relatively low compared with that of the intermediate layer. This geoelectric structure is then used to estimate the influence of the equatorial electrojet on the magnetotelluric measurements carried out in the region. Magnetotelluric forward problems were calculated and compared for cases of the present and the absent of the equatorial electrojet model. Results show that in the range of periods less than 0.7s, the apparent resistivity measured are not affected by the equatorial electrojet. Therefore, the apparent resistivity data measured in the period range less than 0.7s of all stations on the profile have been used for two-dimensional inversion to obtain geoelectric cross-section acrossing the Saigon River fault. The geoelectric cross-section down to a depth of 10km obtained by two-dimensional inversion shows a geoelectric structure consist of 3 layers: a low resistivity superficial layer, a resistive intermediate layer, and a low resistivity underlying layer. The superficial layer is clearly related to the sedimentary series. The intermediate layer may relate to the intrusive and consolidated rocks. The underlying layer may reflect conductive materials causing by high-temperature condition at depth. The interface between the intermediate and the underlying layers at around 3km depth corresponds probably to the crystalline basement. The low resistivity regions under the C4 and C2 stations may be related to the Duong Minh Chau - Dau Tieng - Can Gio and the Saigon River faults, correspondingly.ReferencesS. C. Constable, R. L. Parker, and C. G. Constable, 1987. Occam’ s inversion: A practical algorithm for generating smooth models from EM sounding data, Geophysics, 52, 289-300. H. Grandis, M. Menvielle, and M. Roussignol, 1999. Bayesian inversion with Markovchains-I. Themagnetotelluric one-dimensional case, Geophys. J. Int., 138, 757-768. Trương Quang Hảo, Lương Văn Trương, 2005. Xác định một vài thông số của dòng điện xích đạo ở Việt Nam, Tuyển tập báo cáo Hội nghị khoa học kỹ thuật địa vật lý Việt Nam lần thứ 4, 47-70. Trương Quang Hảo, 1997. Thành tựu nghiên cứu Vật lý Địa cầu 1987-1997. Trung tâm Khoa học Tự nhiên và Công nghệ Quốc Gia, viện Vật lý Địa cầu, Nxb. KHKT, 202-236. Nguyễn Ngọc Hoa (chủ biên), 1995. Bản đồ địa chất và khoáng sản Việt Nam, tỷ lệ 1:200.000, tờ C-48-XI, Thành phố Hồ Chí Minh, Cục Địa chất và Khoáng sản Việt Nam, Hà Nội. Đặng Văn Hưng, 1987. Tính chất của trường điện từ tự nhiên miền xích đạo từ và độ chính xác của của phương pháp MTS ở Việt Nam, Tạp chí các Khoa học về Trái Đất, T.9, 2, 61-66. A. G. Jones, 1992. Electrical conductivity of the continental lower crust, Continental lower crust, Edi. D. M. Fountain, R. J. Arculus and R. W. Kay, 81-143. S. K. Lee et al, 2009. MT2DinvMatlab-A program in MATLAB and FORTRAN for two-dimensional magnetotelluric inversion, Computers Geosciences, 35, 1722-1734. Đỗ Văn Lĩnh (chủ biên), 2009. Báo cáo thuyết minh đề tài “Phân vùng nhỏ động đất khu vực thành phố Hồ Chí Minh”, Sở Khoa học và Công nghệ thành phố Hồ Chí Minh, 248tr. Lê Huy Minh, Nguyễn Văn Giảng, Nguyễn Trọng Vũ và Lại Cao Khiêm, 2004. Kết quả sơ bộ nghiên cứu cấu trúc sâu vùng đồng bằng Sông Cửu Long, Tuyển tập báo cáo Hội nghị Khoa học cơ bản, Thành phố Hồ Chí Minh 12/2004. Lê Huy Minh, Nguyễn Chiến Thắng, Lưu Việt Hùng, 2005. Kết quả đo sâu từ telua tuyến Chợ Gạo- Hóc Môn, Tuyển tập báo cáo Hội nghị Khoa học kỹ thuật Địa vật lý Việt Nam lần thứ 4, 149-161. Lê Huy Minh, Phạm Văn Ngọc, D. Boyer, Nguyễn Ngọc Thủy, Lê Trường Thanh, Ngô Văn Quân, G. Marquis, 2009. Nghiên cứu chi tiết cấu trúc đứt gãy Lai Châu - Điện Biên bằng phương pháp đo sâu từ tellur, Tạp chí Địa chất loạt A, 311, 11 -21. W. R. Peltier and J. F. Hermance, 1971. Magnetotelluric Fields of a Gaussian Electrojet, Canadian Journal of Earth Sciences, 8(3), 338-346. V. N. Pham, D. Boyer, T. K. T. Nguyen, and V. G. Nguyen, 1994. Deep ground-water investigation by combined VES/MTS methods near Ho Chi Minh City, Viet Nam, Ground water, 32, 4, 675-682. P. Tapponier et al., 1990. The Ailao Shan/Red River metamorphic belt: Tertiary left-lateral shear between Indochina and South China, Nature, 343, 431-437. Nguyễn Ngọc Thu, 2004. Xử lý tổng hợp tài liệu địa vật lý vùng thành phố Hồ Chí Minh, Luận án Tiến sĩ vật lý, Đại học Quốc Gia Tp. Hồ Chí Minh, 146tr. Cao Đình Triều, 2005. Trường địa vật lý và cấu trúc thạch quyển lãnh thổ Việt Nam. Nxb. KHKT, Hà Nội, 330tr. Cao Đình Triều, Phạm Huy Long, Đỗ Văn Lĩnh, Lê Văn Dũng, Cao Đình Trọng, 2013. Địa động lực hiện đại lãnh thổ Việt Nam. Nxb. Khoa học Tự nhiên và Công nghệ, 242tr.J. T. Weaver and A. K. Agarwal, 1993. Automatic 1-D inversion of magnetotelluric data by the method of modeling, Geophys. J. Int, 112, 115-123. This  paper  presents the magnetotelluric  sounding  results  of  Cu  Chi  -  Ben  Cat  profile  acrossing  the  Saigon  River fault. Results obtained by one-dimensional inversion of the data of a typical station located near the middle of the profile show that the geoelectric structure of the study area consists of three layers, in which the resistivities of the superficial and the underlying layers are relatively low compared with that of the intermediate layer. This geoelectric structure is then used to estimate the influence of the equatorial electrojet on the magnetotelluric measurements carried out in the region. Magnetotelluric forward problems were calculated and compared for cases of the present and the absent of the equatorial electrojet model. Results show that in the range of periods less than 0.7s, the apparent resistivity measured are not affected by the equatorial electrojet. Therefore, the apparent resistivity data measured in the period range less than 0.7s of all stations on the profile have been used for two-dimensional inversion to obtain geoelectric cross-section acrossing the Saigon River fault. The geoelectric cross-section down to a depth of 10km obtained by two-dimensional inversion shows a geoelectric structure consist of 3 layers: a low resistivity superficial layer, a resistive intermediate layer and a low resistivity underlying layer. The superficial layer is clearly related to the sedimentary series. The intermediate layer may relate to the intrusive and consolidated rocks. The underlying layer may reflect conductive materials causing by high temperature condition at depth. The interface between the intermediate and the underlying layers at around 3km depth corresponds probably to the crystalline basement. The low resistivity regions under the C4 and C2 stations may be related to the Duong Minh Chau - Dau Tieng - Can Gio and the Saigon River faults, correspondingly