基于HEDTA配体修饰的纯红色CsPb(Br/I)_(3)钙钛矿发光二极管

近年来,钙钛矿发光二极管(Perovskite light-emitting diodes,PeLEDs)已表现出了超高色纯度、超宽色域、高发光效率等一系列卓越性能,尤其绿光和近红外光PeLEDs的外量子效率(External quantum efficiency,EQE)和亮度迅速提升,但荧光峰位于620~640 nm的纯红光PeLEDs器件的性能(效率、亮度、可靠性等)发展则相对缓慢。本文采用热注射和N-羟乙基乙二胺三乙酸(HEDTA)配体后处理相结合的工艺制备了光学性能和稳定性均显著提升的纯红色混合卤素钙钛矿CsPb(Br/I)_(3)纳米晶。HEDTA多齿配体通过与纳米晶表面的Pb^(2+)和I-有效结合,钝化表面Pb^(2+)有关的缺陷,同时抑制了致使卤化物偏析的I-弗伦克尔缺陷的形成。基于配体交换处理后的CsPb(Br/I)_(3)纳米晶为发光层制备的PeLEDs,发射峰位于636 nm的纯红色范围,最大EQE和最大亮度分别为18.62%和1880 cd/m^(2)。表征器件工作稳定性的T50(器件亮度衰减至初始亮度一半所需的时间)由未修饰器件的11.4 min提升至74.5 min。

Some Results of Upper and Lower <i>M</i>-Asymmetric Irresolute Multifunctions in Bitopological Spaces

In this paper, we aim to introduce and study some basic properties of upper and lower M-asymmetric irresolute multifunctions defined between asymmetric sets in the realm of bitopological spaces with certain minimal structures as a generalization of irresolute functions deal to Crossley and Hildebrand [1] and upper and lower irresolute Multifunctions deal to Popa [2].

Specificity of Various Mitochondrial DNA (<i>mt</i>DNA), <i>ND5</i>, <i>D-Loop</i>, and <i>Cty-b</i>DNA Primers in Detecting Pig (<i>Sus scrofa</i>) DNA Fragments

Polymerase Chain Reaction (PCR) is an accurate, simple and fast analytical method. This technique is widely used in the identification of meat adulteration and meat-based processed food products. Three Mitochondrial DNA (mt-DNA) primers NADH Dehydrogenase sub unit 5 (ND5), D-Loop, and Cytochrome b (Cyt-b) were tested for their specificity in detecting of pig (Sus scrofa) DNA fragments. DNA genome from 6 meat samples (pork, beef, goat, lamb, and chicken) was amplified by PCR technique using three pairs of primers (ND5, D-Loop, and Cyt-b) and sequenced. The results of amplification using the three primers produced specific DNA bands with the lengths of 232 bp, 951 bp, and 404 bp, respectively. Comparison results with ND5, D-Loop, and Cyt-b gene sequences resulted in similarity values of 100%, 97%, and 99%, respectively. These showed that the mt-DNA primers of ND5, D-Loop, and Cyt-b genes can be recommended as specific primers in detecting pig (Sus scrofa) DNA fragments.

Synthesis of New 2-Phenylamino-4<i>H</i>-chromene-3-carbonitrile Derivatives and Their Effects on Tumor Cell Lines and against Protein Kinases

The synthesis of 2-phenylimino-4H-chromene-3-carbonitriles 6(a-d) in good overall yields using an efficient and practical methodology in 3 steps has been implemented in this present work. The first step was a heterocyclization between 2-hydroxybenzaldehyde 1 and propanedinitrile 2 which produced 2-iminocoumarin 3 which was submitted to nitrogen/nitrogen displacement in the presence of aromatic primary amine 4. In the third step, reduction of 5 led to the desired 2-phenylimino-4H-chromene-3-carbonitriles 6. Compounds 5(a-d) and 6(a-d) were evaluated for their potential in vitro cytotoxicity against six selected tumor cell lines (Huh7-D12, Caco2, MDA-MB231, HCT 116, PC3 and NCI-H727) and tested for their protein kinase inhibition on eight selected protein kinases. Among them, compounds 5c and 6b exhibited inhibition on HsCK1e (5c: 44% and 6b: 42% at 1 μM) and 5c for cytotoxicity on PC3 cell lines (63% at 25 μM).

Efficacy of the Microbial Larvicide VectoMax^®G against <i>Anopheles gambiae</i>s.l. and <i>Culex</i>spp. Larvae under Laboratory and Open Field Trial Experiments in the City of Yaoundé, Cameroon

Background: With the rapid expansion of insecticide resistance limiting the effectiveness of insecticide-based vector control interventions, integrated control strategies associating larviciding could be appropriate to improve current control efforts. The present experimental study assesses laboratory and field efficacy of the larvicide VectoMax®G on Anopheline and Culicine larval stages in Yaoundé. Methods: The effect of the larvicide VectoMax®G, a combination of Bacillus thuringiensis var. israelensis (Bti) and Bacillus sphaericus (Bs), on larval development was assessed during both laboratory and open field trial experiments. Laboratory experiments permitted the evaluation of five different concentrations with four replicates/experiments. Laboratory experiments were conducted with Anopheles coluzzii “Ngousso” and Culex quinquefasciatus laboratory strains. Open field trials were conducted using sixteen plastic containers with a diameter of 0.31 m buried in an array of four rows with 4 containers each. Distance between rows and between containers in a row was 1 meter. This experiment permitted to test the effect of the microbial larvicide VectoMax®G under operational application conditions on field mosquito populations. Results: The time to induce 100% mortality after exposure to serial concentrations of the larvicide varied according to the dose from 4 - 12 hours for An. coluzzii and 6 - 9 hours for Cx. quinquefasciatus in laboratory experiments. Measurements of the residual activity indicated that all VectoMax®G concentrations were still active after 35 days and killed 86% - 100% of larvae. Lethal dose of VectoMax®G killing 50% of larvae was estimated at 5.24 × 10-8 mg/m2 for An. coluzzii and 1.25 × 10-8 mg/m2 for Cx. quinquefasciatus. The lethal concentration inducing 95% mortality was estimated at 3.13 × 10-7 mg/m2 for An. coluzzii and 2.5 × 10-8 mg/m2 for Cx. quinquefasciatus. Open field trials tests indicated that sub-lethal concentrations of VectoMax®G successfully killed 100% An. gambiae s.l. larvae within 24 hours, while with Culex spp. larvae, 100% mortality was recorded after 48 hours post-treatment. Natural recolonization of water containers by larvae was recorded between 3 and 6 days respectively after the treatment with sublethal doses. Late instar larvae were recorded 5 and 6 days after treatment. When the jars were treated with reference dosage or supra doses of VectoMax®G, recolonization of water containers was observed six days after treatments. No pupae of both species were found 6 and 7 days post-treatment. Conclusions: The study indicated high efficacy of the microbial larvicide VectoMax®G against Anopheline and Culex larvae. Microbial larvicides such as VectoMax®G could be appropriate for controlling mosquito population particularly in areas experiencing high insecticide resistance or outdoor biting mosquitoes.

U/I协同学习-创新系统的要素及其函数关系模型

大学 /企业 (U/ I)合作创新既是技术转移过程 ,也是学习过程。本文通过 U/ I合作创新中学习动力机制的分析 ,指出 U/ I合作创新中的学习绩效受学习动力、知识特性、双方组织协同学习能力以及合作双方知识基础的影响。以此为基础 ,建立 U/ I合作创新中学习绩效与各影响因素的函数关系模型。

铁电效应调控的高性能p-NiO/i-BaTiO_(3)/n-ITO自供能紫外光电探测器

近年来,自供能的紫外光电探测器由于无需任何外部偏压即可工作而成为军事和民用领域的研究热点。其中,钛酸钡(BTO)作为一种宽禁带铁电材料,拥有良好的铁电、压电和热电性能,可以产生本征自发极化场来分离光生载流子,从而实现自供能紫外光电探测。到目前为止,基于BTO的自供能光电探测器已经取得了巨大进展,然而,除了使用高质量的单晶材料外,所报道的器件往往表现出低响应度(10^(-8)~10^(-7) A·W^(-1))。本文利用低成本的射频溅射技术,制造了一种高性能的NiO/BTO/ITO p-i-n异质结构自供能紫外光电探测器。通过将BTO的铁电去极化场和p-i-n结的内建电场耦合,能有效提高光生载流子的分离和迁移。因此,该器件在正极化态下255 nm波长紫外光照射下的响应度可以达到3.4×10^(-5) A·W^(-1),远远高于其他已报道的基于非晶态和陶瓷BTO制备的紫外光电探测器。此外,该器件具有0.3 s/0.4 s的快速响应时间。本工作为提高BTO光电探测器的性能提供了一种新的策略。

Physico-Chemical and Thermal Characterization of Some Lignocellulosic Fibres: <i>Ananas comosus</i>(AC), <i>Neuropeltis acuminatas</i>(NA) and <i>Rhecktophyllum camerunense</i>(RC)

This paper focuses on the study of the physical, biochemical, structural, and thermal properties of plant fibres of Rhecktophyllum camerunense (RC), Neuropeltis acuminatas (NA) and Ananas comosus (AC) from the equatorial region of Cameroon. The traditional use of these fibres inspired researchers to investigated their properties. This study aims at improving the state of knowledge with a view to diversifying applications. The fibres are extracted by retting. Then, their apparent density was measured following the ASTM D792 standard and their water moisture absorption and moisture content were also evaluated. Their molecular structure was studied by ATR-FTIR spectroscopy. A quantitative analysis of the biochemical composition was performed according to the analytical technique for the pulp and paper industry (TAPPI). A TGA/DSC analysis was also performed. The results reveal that the AC, NA and RC fibres have densities of 1.26 ± 1.06, 0.846 ± 0.13 and 0.757 ± 0.08 g·cm-3 respectively. They are also hydrophilic with a water absorption rate of 188.64 ± 11.94%, 276.16% ± 8.07% and 198.17% ± 20%. They have a moisture content of 12.21%, 10.36% and 9.37%. The studied fibres exhibit functional groups that are related to the presence of hemicellulose, pectin, lignin and cellulose. The cellulose crystallinity index was found to be 67.99%, 46.5% and 59.72% respectively. The fibres under study have the following chemical composition: an extractive content of 3.07%, 14.77% and 8.74%;a pectin content of 4.15%, 7.69% and 3.45%;a hemicellulose content of 4.90%, 15.33% and 7.42%;a cellulose content of 68.11%, 36.08% and 65.15%;a lignin content of 12.01%, 25.15% and 16.2%;and an ash content of 0.27%, 1.53% and 0.47% respectively. The thermal transitions observed on the thermograms correlate with the TAPPI chemical composition. It is observed that these fibres are thermally stable up to temperatures of 200°C, 220°C and 285°C. These results make it possible to envisage uses similar to those of sisal, hemp and flax fibres.

On <i>M</i>-Asymmetric Semi-Open Sets and Semicontinuous Multifunctions in Bitopological Spaces

The purpose of this paper is to introduce the notions of m-asymmetric semiopen sets and M-asymmetric semicontinuous multifunctions defined between asymmetric sets satisfying certain minimal conditions in the framework of bitopological spaces. Some new characterizations of m-asymmetric semiopen sets and M-asymmetric semicontinuous multifunctions will be investigated and several fundamental properties will be obtained.

<i>Campylobacter, Salmonella</i>and <i>Escherichia coli</i>Food Contamination Risk in Free-Range Poultry Production System

Livestock such as poultry is consumed as food worldwide and it constitutes one of the main protein sources for diners, as well as an important source of revenue generation for farmers. Poultry meat production chain identifies a significant role of the farm to folk. Most often, the systems used in poultry production can result in a higher prevalence of Campylobacter, Salmonella, and Escherichia coli contamination, leading to adverse health effects with detrimental consequences. The method of poultry keeping plays a significant role in the poultry meats’ outcome and its food safety standards. Farmers attempt to develop new poultry operations, however, there are two main possibilities;to operate within the present vertically integrated system which is incredibly good for disease prevention and to develop independently, or a smaller operation that is more animal friendly. This article reviews the available research on the impact of free-range poultry production systems on food safety, most importantly the prevalence and control of Campylobacter, Salmonella and Escherichia coli in free-range production systems. The results suggest a conflicting view when bacterial loads of poultry meat from conventional and free-range systems are compared. Studies have shown increased bacterial loads in a free-range production system.

Antibacterial Activities of <i>Psidium guajava</i>(Guava) and <i>Velvet tamarin</i>(Icheku) Local Chewing Sticks on <i>Streptococcus mutans</i>Isolated from Human Mouth

Globally dental diseases are mainly caused by Streptococcus mutans, it is one of the leading causative agents of dental caries worldwide, because of its resistance to conventional antibacterial agents, alternative therapies are used to control resistance of oral pathogens. This research was done to determine the antibacterial activities of Psidium guajava (guava) and Velvet tamarin (Icheku) chewing sticks on Streptococcus mutans isolated from the oral cavity. The study was conducted in Owerri Imo State Nigeria during November-December period. Phytochemical analysis of the plant extracts was done using appropriate techniques. The procedure used for antimicrobial susceptibility test was disk diffusion method. Serial dilutions of Psidium guajava (guava) and Velvet tamarind (Icheku) extracts were prepared, Muller-Hinton media was used to put together the extract of serial dilutions of Psidium guajava (guava) and Velvet tamarin (Icheku) and a microbiological procedure were used for visually determining the minimum inhibitory concentration as well as minimum bactericidal concentration. Phytochemical evaluation of the plants’ extracts revealed that it contains saponins, tannins, alkaloid, steriods, glycosides and phenol. The results obtained from the antibacterial susceptibility testing of the extracts against Streptococcus mutans showed that the zones of inhibition recorded ranged from 18 mm to 27 mm. Ethanol (Soxhlet) extract of Icheku twig showed no zone of inhibition on the isolated organism. The ethanol (soxhlet) extract of the individual Psidium guajava (guava) and Velvet tamarin (Icheku) has a better antibacterial effect when compared to their aqueous extracts and combined forms. Psidium guajava (Guava) and Velvet tamarin (Icheku) twigs are made up of composite that is active against S. mutans and can be used in oral hygiene. There is a need for further investigation on the plant extracts as the rural poor make use of it because it is cheap, readily available and the rich also use it once they are in the village mostly in Eastern Nigeria. Similarly chewing sticks has been reported to be practiced by 90 of rural population in Nigeria.

Compound’s Pre-Screening of <i>Withania somnifera</i>, <i>Bacopa monnieri</i>and <i>Centella asiatica</i>Extracts

Spectral fluorescence signature, Gas Chromatography-Mass Spectrometry and Liquid Chromatography-Mass Spectrometry for identification of chemical and bioactive compounds were applied to study the plant extracts of Withania somnifera, Centella asiatica and Bacopa monnieri which are related to the possible treatment of mental diseases as Alzheimer, Parkinson and Depression. These plants are known for different positive phytotherapeutic effects on the human brain without negative post-, adverse or after effects to the treated individuals, and have been recommended in several medical studies. Therefore, we selected these plants for further analysis, based on the inhibition results of in vitro Amyloid Beta fibrillation tests made by previous measurements. With this study a first screening of the complex plant extract mixtures was performed, to get an initial overview about known and unknown ingredients. In all three plants, similar main compounds were identified, however in different quality and quantity. These may provide substantial information on which compound combinations might be mainly responsible for the positive effects and should be further investigated being responsible for reducing the fibrillation process of Amyloid Beta.

Potential of Binahong (<i>Anredera cordifolia</i>[Tenore] Steen) in Reducing TNF-<i>α</i>Expression on Regeneration of Pancreas <i>β</i>Cells on White Rats (<i>Rattus norvegicus</i>) Diabetes Mellitus Models

Diabetes mellitus (DM) is a metabolic disorder characterized by increased blood glucose levels (hyperglycemia) due to impaired insulin secretion and/or increased insulin resistance. Providing binahong leaf steeping (Anredera cordifolia [Tenore] Steen) is one alternative treatment for people with diabetes mellitus using medicinal plants. This research was conducted to find out the right concentration by administering binahong leaf steeping to reduce hyperglycemia in STZ induced rat and to analyze administration of binahong leaf steeping in reducing TNF-α expression in pancreatic β cell regeneration. This study used 25 white rats (Rattus novergicus) which were divided into 5 groups: group 1, negative control (K-), group 2, positive control (K+), groups 3, 4, and 5. With STZ induction, each is given a dose of binahong leaf steeping, 50.4 mg/180ml of water;100.8 mg/180ml of water and 151.2 mg/180ml of water for 14 days. The results showed that the administration of binahong leaf steeping to STZ induced rat could reduce glucose rats in a row by 130.00, respectively;117,23 and 112,45 and steeping binahong leaves (Anredera cordifolia [Ten] S) significantly influence the reduction in TNF-α expression in pancreatic β cell regeneration. Thus, this study can be concluded that the right dose to reduce hyperglycemic and regeneration of pancreatic β cells produced by STZ induced rats is 151.2 mg/180ml of water and statistically influences in reducing TNF-α expression in pancreatic β cell regeneration.

Total Phenolic Compounds, Carotenoids and <i>In Vitro</i>Antioxidant Activity of Three Traditional Indigenous Medicinal Plants of Saskatchewan, Canada

Medicinal plants are an important component in Indigenous cultures. Aralia nudicaulis L., Rubus idaeus L., and Rosa arkansana Porter were analyzed for total phenolic compounds, carotenoids and antioxidant activity by DPPH (2,2-diphenyl-1-picrylhydrazyl), FRAP (ferric-reducing antioxidant power), and ABTS (2,2-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid). The samples were harvested in Saskatchewan, Canada, with the help of an Indigenous Traditional Knowledge Keeper and the analyses were performed by spectrophotometry. The results showed that total phenolic compounds amount ranged from 0.08 to 0.88 mg GAE/mg d.w. and the total carotenoid contents ranged from 0.03 to 1.26 mg/g d.w. The in vitro antioxidant activity ranged from 0.02 to 0.71 μmol TE/mg d.w. by DPPH, from 0.05 to 2.53 μmol TE/mg d.w. by FRAP, and from 0.04 to 1.06 μmol TE/mg d.w. by ABTS. Rosa arkansana leaves stood out with higher amounts of total phenolic compounds (TPC) (0.88 ± 0.02 mg GAE/g d.w.), carotenoids (TC) (1.26 ± 0.03 mg/g d.w.) and antioxidant activity (TAA) by DPPH (0.71 ± 0.01 μmol TE/mg d.w.), ABTS (1.06 ± 0.01 μmol TE/mg d.w.) and FRAP (2.32 ± 0.01 μmol TE/mg d.w.), with the same amount of Rubus idaeus belowground (2.53 ± 0.01 μmol TE/mg d.w.) in last technique (2.32 ± 0.01 μmol TE/mg d.w.). The first principal component describes 83.88% of the total variance and all the variables have high influence on this component (factor loadings: T = 0.976, TC = 0.735, TAA by DPPH = 0.955, FRAP = 0.894 and ABTS = 0.996), demonstrating that these samples do not have large dissimilarity. The second principal component represents 13.64% of the total variance, and the TC is the dominant variable on the second principal component (0.658). Aralia nudicaulis, Rubus idaeus, and Rosa arkansana had interesting amounts of total phenolic compounds, total carotenoids and in vitro antioxidant activity. Rosa arkansana leaves and Rubus idaeus have the highest amount of total phenolic compounds and antioxidant activity in this study. Rosa arkansana leaves are also a good source of carotenoids, and so, they have great potential health benefits and use in industry as a source of bioactive compounds with high antioxidant activity. This study enriches the literature on medicinal plants used by Indigenous people of Saskatchewan and surrounding Canada. More studies are necessary to identify its applications, security and to assess which compounds generate the benefits reported by Traditional Knowledge Keepers.

Binary Vector Construction for Site-Directed Mutagenesis of <i>Kafirin</i>Genes in Sorghum

Sorghum (Sorghum bicolor (L.) Moench) is one of the world’s leading cereal crops in agricultural production, which has a special importance in the arid regions. However, unlike other cereals, sorghum grain has a lower nutritional value, which is caused, inter alia, by the resistance of its seed storage proteins (kafirins) to protease digestion. One of the effective approaches to improve the nutritional value of sorghum grain is to obtain mutants with partially or completely suppressed synthesis or altered amino acid composition of kafirins. The employment of genome editing may allow to solve this problem by introducing mutations into the nucleotide sequences of the α- and γ-kafirin genes. In this study, genomic target motifs (23 bp sequences) were selected for the introduction of mutations into the α- and γ-KAFIRIN genes of sorghum. The design of the gRNAs was conducted using the online tools CRISPROR and CHOPCHOP. Two most suitable targets were chosen for α-KAFIRIN (k1C5) and two for γ-KAFIRIN (gKAF1) genes. The insertion of respective sequences in the generic vector pSH121 was performed at the BsaI (Eco31I) sites. Validation of the cloning procedure was performed by DNA sequencing. Subcloning of the resulting constructs was performed using the SfiI restriction sites into the compatible binary vector B479p7oUZm-LH. The correct assembly of binary vectors was confirmed by restriction analysis using the MluI and SfiI cleavage sites. The four vectors created (1C - 4C) were transferred by electroporation into the Agrobacterium tumefaciens strain AGL0. Currently, this vector series is used for stable transformation of sorghum using immature embryo explants.

<i>Cedecea lapagei</i>in a Patient with Multiple Injuries: Report of a Rare Case

Cedecea lapagei (C. lapagei) is an opportunistic pathogen in old patients with many comorbid diseases and the immunosuppressed. It is a gram-negative, facultative anaerobe bacterium of the Enterobacteriaceae family. We present a rare case of a patient with multiple injuries, C. lapagei was found from the exudate of the wound, what’s more, the Proteus vulgaris was also found in blood culture medium at the same time. According to the available literature, this is the first case of simultaneous infection of two bacteria including C. lapagei and Proteus vulgaris from the exudate of the traumatic wound.

Field Efficacy of a Biopesticide Based on <i>Tithonia diversifolia</i>against Black Sigatoka Disease of Plantain (<i>Musa</i>spp., AAB)

Black Sigatoka disease (BSD) is a foliar disease caused by Mycosphaerella fijiensis, responsible of reduction of the photosynthetic area of banana plant and yield at harvest since it has an influence on fruit physiology. The control of BSD relies on the use of chemicals which are not affordable for the small holder farmers and increase the cost of production. Moreover, this chemical control is ineffective, negatively impacting the environment and human health, and is at the origin of strain resistance. Tithonia diversifolia is known as rich in many compounds such as mineral elements, defense metabolites, some phytochemicals;and it is increasingly used in agriculture. Recently, the protective effect of Tithonia diversifolia liquid extract against BSD development on plantain vivoplants in the nursery was highlighted. The aim of our study was to evaluate the efficacy of a biopesticide base on Tithonia diversifolia on the BSD development in a plantain field under high disease pressure. The effect of Tithonia diversifolia biopesticide on Mycosphaerella fijiensis mycelial growth in vitro was evaluated. An experimental field at the flowering stage was selected and treated with the biopesticide base on Tithonia diversifolia at three different concentrations: undiluted (100%), diluted at 1/2 (50%) and diluted at 1/4 (25%) for 17 weeks. The disease severity, the number of functional leaves, the youngest spotted leaf (YSL) and the youngest necrotic leaf (YNL) were evaluated in course of time. The biopesticide treatments significantly (P < 0.001) reduce the BSD severity in course of time, but it is more effective for the most diluted concentration (25%). The number of leaves increases in course of time as well as the rank of the YSL and the YNL confirming the efficiency of BSD control. The efficacy of this biopesticide base on Tithonia diversifolia could be a hopeful ecoresponsible solution for the plantain sector in general and in particular for poor small farmers.

Application of <i>q</i>-Calculus to the Solution of Partial <i>q</i>-Differential Equations

We introduce the concept of q-calculus in quantum geometry. This involves the q-differential and q-integral operators. With these, we study the basic rules governing q-calculus as compared with the classical Newton-Leibnitz calculus, and obtain some important results. We introduce the reduced q-differential transform method (RqDTM) for solving partial q-differential equations. The solution is computed in the form of a convergent power series with easily computable coefficients. With the help of some test examples, we discover the effectiveness and performance of the proposed method and employing MathCAD 14 software for computation. It turns out that when q = 1, the solution coincides with that for the classical version of the given initial value problem. The results demonstrate that the RqDTM approach is quite efficient and convenient.

利用SSM/I数据判识我国及周边地区雪盖

积雪参数是气候学和水文学研究中所需的重要物理量,确保积雪参数测定的准确性与及时性对于气候学研究、水文应用以及防灾减灾都非常重要。利用微波数据可获取有云存在时的积雪覆盖图,遥感雪深和雪水当量信息。采用微波数据判识雪盖并得到积雪状态(干、湿)信息,不仅可以弥补利用光学遥感数据判识雪盖的不足之处,而且也是利用微波数据反演雪深和雪水当量参数必需的先期工作。该文介绍利用SSM/I的多频双极化微波数据开展我国及周边地区积雪判识方法研究的结果。分析国外全球判识方法的雪盖判识结果指出,国外算法易在青藏高原等地区将冻土误判为积雪,造成雪盖面积的偏高估计。研究给出了在我国及周边地区(17°-57°N,65°-145°E)利用SSM/I数据判识积雪的改进方法,在完成积雪判识的同时还给出了雪深和积雪状态的定性信息,与已有全球雪盖判识方法相比有较大改进,大大减小了青藏高原等地区冻土对积雪判识的影响。

Clinical Impact of Bacteremia Due to <i>Staphylococcus saprophyticus</i>

Objective: This was a retrospective study to evaluate the clinical impact of bacteremia due to Staphylococcus saprophyticus and identify which factors influence it. Methods: We reviewed all patients with bacteremia due to S. saprophyticus over the last 12 years. This study was performed at Jichi Medical University Hospital in Japan, a key hospital in the northern Kanto area including Tochigi, Gunma, Ibagagi, and northern Saitama prefectures. We retrospectively reviewed the blood culture results and medical records of all patients with a history of visits or hospitalizations between April 2008 and September 2020. Results: During the study period, 4 blood culture specimens were considered to have S. saprophyticus bacteremia. Two of these were from subjects > 60 years old who had severe infection. A third case, 27 years old, was thought to have a catheter-related bloodstream infection;however, the only symptom was fever, which was not serious. The fourth case, a previously unreported pediatric patient, had non-severe fever. The mean time for a diagnosis of bacteremia by blood culture testing was 42 hours, whereas contamination appeared in cultures after another 50 hours. Conclusion: The pathogenicity of S. saprophyticus might be lower in the blood than in the urine due to its physiological function and activity. In older adults with underlying diseases, the severity of bacteremia was more pronounced, whereas in a young adult and a child, the disease was relatively mild. Age and underlying disease might be useful factors to consider when diagnosing bacteremia due to S. saprophyticus.