检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

对数视频放大器

国外红外与激光技术 1977年第Z2期 65-111页

作者： Richard s.hughes

前言许多电量的测量必须在很宽的动态范围中进行。对雷达接收机、遥测装置和通讯接收机的输入信号在短时间间隔内常常从几微伏改变到几伏。激光测距仪的返回脉冲可能变化若干数量级,这要看目标的瞬时几何形状而定。就上述要求来说,瞬时... 详细信息

前言许多电量的测量必须在很宽的动态范围中进行。对雷达接收机、遥测装置和通讯接收机的输入信号在短时间间隔内常常从几微伏改变到几伏。激光测距仪的返回脉冲可能变化若干数量级,这要看目标的瞬时几何形状而定。就上述要求来说,瞬时动态范围的限制因素常常是线性接收放大器。

关键词：对数放大器动态范围线性放大器对数转换线性增益代入对数变换方程

Percutaneous hepatic perfusion with melphalan for unresectable liver metastasis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Hepatoma Research 2016年第1期2卷 197-202页

作者： Humair s.Quadri Eden C.Payabyab David J.Chen William Figg Marybeth s.hughes Thoracic and Gastrointestinal Oncology Branch National Cancer InstituteBethesdaMD 20892USA Genitourinary Malignancies Branch National Cancer InstituteBethesdaMD 20892USA

Percutaneous hepatic perfusion(PHP)is an investigative technique for treating patients with diffuse unresectable metastatic liver *** technique has been clinically evaluated and shows great treatment potential for regional therapy to the *** advantage of PHP lies in its minimally invasive approach and ability to be repeated when compared to isolated hepatic *** a literature search,135 publications were screened and 16 of these publications,including clinical trials and reviews,contributed to this review of PHP with *** is an alkylating agent that,when used as the chemotherapeutic agent in PHP,has shown potential for significant control of tumor burden in the liver,especially in metastatic ocular *** the current landscape of liver directed therapy,PHP is a viable option for those with unresectable metastatic disease to the *** article will focus on the technical aspects of PHP and describe the current data available from clinical trials,including outcomes of patients treated with this minimally invasive approach.

关键词： Percutaneous hepatic perfusion melphalan unresectable liver metastasis metastatic melanoma to the liver ocular melanoma

Evaluating COVID-19’s impacts on Puerto Rican’s travel behaviors

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geo-spatial Information science 2023年第4期26卷 616-626页

作者： lauren C.Carter Ran Tao school of Geosciences University of South FloridaTampaFLUSA

The COVID-19 pandemic has completely disrupted and possibly permanently changed the way humans *** Puerto Rico,major travel restrictions to the island have persisted at different levels since March 2020,which heavily influenced residents’travel ***,it remains unclear about how big the impact is and how inequitable it might *** goal of this study is to evaluate COVID-19’s impacts on Puerto Rican’s travel behaviors by analyzing travel flows from Puerto Rico to the contiguous Us with a modified gravity *** roles of socioeconomic factors regarding the Puerto Rican travelers and COVID-19 factors regarding the destination Us states have been ***-19 was a strong deterring factor of travel at the beginning of the pandemic and also in the winter of 2020,but it did not keep Puerto Ricans from traveling during the summer 2020 when most travel restrictions were *** found that the elderly population of Puerto Rico,despite being more vulnerable to COVID-19,were much more likely to travel during the *** also found that,during the holiday season in 2020,some socioeconomically disadvantaged populations were more likely to be traveling,a direct contradiction to their travel flows the year *** findings shed light on about how disproportionately affected populations behavior changed from pre-pandemic to after the pandemic *** the continuance of the pandemic,this information is extremely valuable for future planning with respect to emergency management,travel regulation,and social benefit.

关键词： COVID-19 Puerto Rico travel behavior social vulnerability human mobility

stuck in a rut： Potential costs of sand roads to gopher tortoises Gopherus polyphemus

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2015年第4期61卷 578-585页

作者： lauren N. GILsON Archbold Biological station Lake Placid 123 Main Drive. Lake Placid. FL 33960. USA Department of Environment and Agriculture Curtin University Bentley WA 6845 Australia

Roads affect wildlife significantly through direct mortality but also through behavioral change. We explored the ef- fects of unsurfaced sand roads with a low traffic volume on the travelling behavior of gopher tortoises Gopherus polyphemus in scrub habitat in central Florida, as evidenced by the tracks left by tortoises on sand roads. Tortoises （and most other taxa leaving tracks on the roads） did not appear to make use of roads for travel but attempted to cross them, the success of which was influ- enced by the size of the individual. smaller animals （presumably younger tortoises） were more challenged than larger animals by both sand road widths and depths of vehicle ruts in sand roads. sand roads may present both physical and physiological challenges to gopher tortoises, particularly to small ones. This research provides further evidence that the negative influence of roads in fragmenting the environment is not limited to vehicle mortality [Current Zoology 61 （4）： 578-585, 2015].

关键词： Travel Non-lethal effects of roads Testudine Reptile size-dependent

Insects: an underrepresented resource for the discovery of biologically active natural products

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Pharmaceutica sinica B 2017年第4期7卷 409-426页

作者： lauren seabrooks Longqin Hu Department of Medicinal Chemistry Ernest Mario School of Pharmacy Rutgers The State University of New Jersey Cancer Institute of New Jersey

Nature has been the source of life-changing and-saving medications for centuries. Aspirin,penicillin and morphine are prime examples of Nature's gifts to medicine. These discoveries catalyzed the field of natural product drug discovery which has mostly focused on plants. However, insects have more than twice the number of species and entomotherapy has been in practice for as long as and often in conjunction with medicinal plants and is an important alternative to modern medicine in many parts of the world. Herein, an overview of current traditional medicinal applications of insects and characterization of isolated biologically active molecules starting from approximately 2010 is presented. Insect natural products reviewed were isolated from ants, bees, wasps, beetles, cockroaches, termites, flies, true bugs,moths and more. Biological activities of these natural products from insects include antimicrobial,antifungal, antiviral, anticancer, antioxidant, anti-inflammatory and immunomodulatory effects.

关键词： Natural products Insects Entomotherapy Traditional medicine Drug discovery

Neural lineage differentiation of human pluripotent stem cells:Advances in disease modeling

在线全文

学校读者我要写书评

暂无评论

World Journal of stem Cells 2023年第6期15卷 530-545页

作者： Yuan-Wei Yan Eddie s Qian lauren E Woodard Julie Bejoy Waisman Center University of Wisconsin-MadisonMadisonWI 53705United States Nephrology and Hypertension Vanderbilt University Medical CenterNashvilleTN 37232United States Department of Medicine Vanderbilt University Medical CenterNashvilleTN 37232United States Department of Veterans Affairs Tennessee Valley Healthcare SystemNashvilleTN 37232United States Biomedical Engineering Vanderbilt UniversityNashvilleTN 37232United States

Brain diseases affect 1 in 6 people *** diseases range from acute neurological conditions such as stroke to chronic neurodegenerative disorders such as Alzheimer’s *** advancements in tissue-engineered brain disease models have overcome many of the different shortcomings associated with the various animal models,tissue culture models,and epidemiologic patient data that are commonly used to study brain *** innovative method by which to model human neurological disease is via the directed differentiation of human pluripotent stem cells(hPsCs)to neural lineages including neurons,astrocytes,and ***-dimensional models such as brain organoids have also been derived from hPsCs,offering more physiological relevance due to their incorporation of various cell *** such,brain organoids can better model the pathophysiology of neural diseases observed in *** this review,we will emphasize recent developments in hPsC-based tissue culture models of neurological disorders and how they are being used to create neural disease models.

关键词： Induced pluripotent stem cells Astrocytes Oligodendrocytes Microglia Brain organoids Assembloids

Combined influence of Ce(Ⅲ)and iodide ions for corrosion protection of AA 2024-T3 in acidic to neutral chloride-rich environments:Electrochemical and surface characterization studies

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2023年第2期41卷 309-320页

作者： Mohammed A.El-Hashemy Anthony E.hughes Thomas Gengenbach A.Matthew Glenn Ivan s.Cole Chemistry Department College of ScienceJouf UniversityP.O.Box 2014SakakaAljoufSaudi Arabia Air Pollution Research Department Environmental and Climate Change Research InstituteNational Research CentreDokkiGiza12622Egypt CsIRO Mineral Resources ClaytonVic3168Australia CsIRO Manufacturing ClaytonVic3168Australia school of Engineering RMIT UniversityCarltonVic3053Australia

It has been reported that trivalent cerium salts are effective inhibitors for corrosion of AA2024-T3 in neutral to alkaline co rrosive enviro nments,but poor in acidic *** this study,work was done for extending corrosion resistance provided by Ce(NO_(3))_(3)to acidic pHs as low as 2.5 through the addition of iodide *** this end,potentiodynamic polarization was used to ascertain the optimum Ce(Ⅲ)concentration for the inhibition of AA2024-T3 corrosion in 3.5%NaCl *** optimum concentration is found to be in a range between 0.1 and 0.3 mmol/L Ce(Ⅲ).This optimum concentration also gives a maximum width of the passive region under the pitting potential(Epit).Based on this optimization,further work was performed as a function of pH without and in the presence of 0.01 mol/L KI at five pH values(2.5,4,5,7,and 8).Without iodide the best inhibition provided by the Ce(Ⅲ)cation is at pH=7 but active corrosion is observed at pH=2.5 with an estimated inhibitor efficiency(-37.6%).The addition of iodide ions(I^(-))reverses the poor corrosion resistance whereby the inhibitor efficiency becomes 47.7%.Moreover,at pH=4 the efficiency is also increased from 54.0%to 81.0%with iodide addition providing a significant improvement over Ce(Ⅲ)cations alone under acidic *** is a synergistic effect between I-anion and Ce(Ⅲ)cation,which is determined to be 2.4 and 2.1 at pH=2.5and 4.0,*** pH=5 and 7 there is virtually no change in inhibition but at pH=8 the inhibition falls away due to a considerable amount of cerium precipitating out of solution as cerium *** protective film formed on sites in the aluminium alloy surface at different pH values was examined by both scanning electron microscopy with energy dispersive X-ray analysis and X-ray photoelectron spectroscopy to determine the role of these ions as a function of pH in surface *** is proposed that at pH=2.5 protection is provided by a bilayer adsorption of iodide with"cap

关键词： Aluminium alloy Cerium(Ⅲ)salt Potassium iodide Corrosion inhibitor XPs Rare earths

Transcatheter Device Closure of a Perimembranous Ventricular septal Defect in Congenitally Corrected Transposition of the Great Arteries

在线全文

学校读者我要写书评

暂无评论

Congenital Heart Disease 2022年第2期17卷 193-199页

作者： Catherine E.Tomasulo Lindsay s.Rogers lauren Andrade Michael LO’Byrne Division of Cardiology The Children’s Hospital of PhiladelphiaPhiladelphiaUSA Division of Cardiology Hospital of the University of PennsylvaniaPhiladelphiaUSA Center for Pediatric Clinical Effectiveness The Children’s Hospital of PhiladelphiaPhiladelphiaUSA Leonard Davis Institute and Center for Cardiovascular Outcomes Qualityand Evaluative ResearchUniversity of PennsylvaniaPhiladelphiaUSA

The majority of patients with congenitally corrected transposition of the great arteries,also known as transposition of the great arteries{s,L,L}have ventricular septal defects(VsD),most commonly perimembranous VsD(pmVsD).Transcatheter device closure of pmVsD in these patients has not been widely *** present a case of device closure of pmVsD in L-TGA with an Amplatzer Duct Occluder II(ADOII)device using a deployment starting in the subpulmonary left *** case demonstrates some of the technical advantages of the ADOII device for VsD closure,specifically its low profile,symmetric shape,and soft *** characteristics are advantageous in closing conventional pmVsD but are especially useful in patients with challenging anatomic substrates.

关键词： Percutaneous catheterization congenital heart disease thromboembolism

Do forest health threats affect upland oak regeneration and recruitment?Advance reproduction is a key co-morbidity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Forest Ecosystems 2023年第6期10卷 743-751页

作者： Lance A.Vickers Benjamin O.Knapp Daniel C.Dey lauren s.Pile Knapp school of Natural Resources University of Missouri203 Anheuser-Busch Natural Resources BuildingColumbiaMO65211USA UsDA Forest service Northern Research station 202 Anheuser-Busch Natural Resources BuildingColumbiaMO65211USA

We analyzed national forest inventory data collected from circa 2000–2018 across 37 states in the eastern United states to better understand the influence of forest health related canopy disturbances on the regeneration and recruitment dynamics of upland oaks(Quercus).We found low levels of oak recruitment across all disturbance types examined but limited evidence of any direct effects from the type of disturbance on the population of regenerating *** general lack of differences in oak regeneration response between forest health disturbances and disturbances caused by harvested or non-disturbed plots does not indicate that the effects of forest health disturbances were benign,***,low level of oak recruitment across all disturbance types highlights the pervasiveness of the trend of shifting composition in once oak-dominated forests where oak is absent or sparse in the regeneration *** results show that oak recruitment was higher when oak was present as advance reproduction prior to disturbance from any cause ***,these results lead us to conclude that the widespread inadequacy of oak advance reproduction in mature oak-dominated forests is the prevailing threat to oak forest health and *** suggest the status of advance reproduction be treated as a co-morbidity when weighing the risk and potential outcomes from other threats to upland oak forests in the eastern United states.

关键词： Temperate deciduous forest Regeneration ecology Forest inventory and analysis Oak/hickory Forest pests Insect Disease Harvesting