抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

/pdf/self-assembled-monolayers-of-thiolates-on-metals-as-a-form-1neb0hj3k4.pdf

Self-assembled monolayers of thiolates on metals as a form of nanotechnology.

Microfabricated integrated circuits revolutionized computation by vastly reducing the space, labor, and time required for calculations. Microfluidic systems hold similar promise for the large-scale automation of chemistry and biology, suggesting the possibility of numerous experiments performed rapidly and in parallel, while consuming little reagent. While it is too early to tell whether such a vision will be realized, significant progress has been achieved, and various applications of significant scientific and practical interest have been developed. Here a review of the physics of small volumes (nanoliters) of fluids is presented, as parametrized by a series of dimensionless numbers expressing the relative importance of various physical phenomena. Specifically, this review explores the Reynolds number Re, addressing inertial effects; the Peclet number Pe, which concerns convective and diffusive transport; the capillary number Ca expressing the importance of interfacial tension; the Deborah, Weissenberg, and elasticity numbers De, Wi, and El, describing elastic effects due to deformable microstructural elements like polymers; the Grashof and Rayleigh numbers Gr and Ra, describing density-driven flows; and the Knudsen number, describing the importance of noncontinuum molecular effects. Furthermore, the long-range nature of viscous flows and the small device dimensions inherent in microfluidics mean that the influence of boundaries is typically significant. A variety of strategies have been developed to manipulate fluids by exploiting boundary effects; among these are electrokinetic effects, acoustic streaming, and fluid-structure interactions. The goal is to describe the physics behind the rich variety of fluid phenomena occurring on the nanoliter scale using simple scaling arguments, with the hopes of developing an intuitive sense for this occasionally counterintuitive world.

/pdf/microfluidics-fluid-physics-at-the-nanoliter-scale-4bpahtd8qa.pdf

Microfluidics: Fluid physics at the nanoliter scale

Detection of chemical and biological agents plays a fundamental role in biomedical, forensic and environmental sciences1–4 as well as in anti bioterrorism applications.5–7 The development of highly sensitive, cost effective, miniature sensors is therefore in high demand which requires advanced technology coupled with fundamental knowledge in chemistry, biology and material sciences.8–13

In general, sensors feature two functional components: a recognition element to provide selective/specific binding with the target analytes and a transducer component for signaling the binding event. An efficient sensor relies heavily on these two essential components for the recognition process in terms of response time, signal to noise (S/N) ratio, selectivity and limits of detection (LOD).14,15 Therefore, designing sensors with higher efficacy depends on the development of novel materials to improve both the recognition and transduction processes. Nanomaterials feature unique physicochemical properties that can be of great utility in creating new recognition and transduction processes for chemical and biological sensors15–27 as well as improving the S/N ratio by miniaturization of the sensor elements.28

Gold nanoparticles (AuNPs) possess distinct physical and chemical attributes that make them excellent scaffolds for the fabrication of novel chemical and biological sensors (Figure 1).29–36 First, AuNPs can be synthesized in a straightforward manner and can be made highly stable. Second, they possess unique optoelectronic properties. Third, they provide high surface-to-volume ratio with excellent biocompatibility using appropriate ligands.30 Fourth, these properties of AuNPs can be readily tuned varying their size, shape and the surrounding chemical environment. For example, the binding event between recognition element and the analyte can alter physicochemical properties of transducer AuNPs, such as plasmon resonance absorption, conductivity, redox behavior, etc. that in turn can generate a detectable response signal. Finally, AuNPs offer a suitable platform for multi-functionalization with a wide range of organic or biological ligands for the selective binding and detection of small molecules and biological targets.30–32,36 Each of these attributes of AuNPs has allowed researchers to develop novel sensing strategies with improved sensitivity, stability and selectivity. In the last decade of research, the advent of AuNP as a sensory element provided us a broad spectrum of innovative approaches for the detection of metal ions, small molecules, proteins, nucleic acids, malignant cells, etc. in a rapid and efficient manner.37



Figure 1

Physical properties of AuNPs and schematic illustration of an AuNP-based detection system.



In this current review, we have highlighted the several synthetic routes and properties of AuNPs that make them excellent probes for different sensing strategies. Furthermore, we will discuss various sensing strategies and major advances in the last two decades of research utilizing AuNPs in the detection of variety of target analytes including metal ions, organic molecules, proteins, nucleic acids, and microorganisms.

/pdf/gold-nanoparticles-in-chemical-and-biological-sensing-5e2qojkdzn.pdf

Gold nanoparticles in chemical and biological sensing.

5.1. Detection Formats 475 5.2. Food Quality and Safety Analysis 477 5.2.1. Pathogens 477 5.2.2. Toxins 479 5.2.3. Veterinary Drugs 479 5.2.4. Vitamins 480 5.2.5. Hormones 480 5.2.6. Diagnostic Antibodies 480 5.2.7. Allergens 481 5.2.8. Proteins 481 5.2.9. Chemical Contaminants 481 5.3. Medical Diagnostics 481 5.3.1. Cancer Markers 481 5.3.2. Antibodies against Viral Pathogens 482 5.3.3. Drugs and Drug-Induced Antibodies 483 5.3.4. Hormones 483 5.3.5. Allergy Markers 483 5.3.6. Heart Attack Markers 484 5.3.7. Other Molecular Biomarkers 484 5.4. Environmental Monitoring 484 5.4.1. Pesticides 484 5.4.2. 2,4,6-Trinitrotoluene (TNT) 485 5.4.3. Aromatic Hydrocarbons 485 5.4.4. Heavy Metals 485 5.4.5. Phenols 485 5.4.6. Polychlorinated Biphenyls 487 5.4.7. Dioxins 487 5.5. Summary 488 6. Conclusions 489 7. Abbreviations 489 8. Acknowledgment 489 9. References 489

Surface Plasmon Resonance Sensors for Detection of Chemical and Biological Species

Purpose: This study aimed to identify the factors influencing suicide attempts among middle school students with suicidal ideation. Methods: Data were from the 2019 Youth Health Risk Behavior Web-based survey collected by the Korea Centers for Disease Control and Prevention. The data were analyzed using the SPSS program. Results: Participants were 29,384 middle school students, there were 14.1% of suicide ideation, and 22.2% of them attempted suicide. Among the students with suicidal thoughts, suicide attempts were higher in those who had experiences of alcohol drinking, smoking, substance abuse, and sexual intercourse. Conclusion: Therefore, to prevent suicide accidents among middle school students, there is a need for strategies that would reduce problem behavior such as alcohol drinking, smoking, sexual intercourse, and substance abuse. For middle school students who have already experienced problem behavior, efficient plans should be established for screening, prevention, and treatment of the high-risk groups in suicide attempts.

Predictors of Suicide Attempt among Middle School Students with Suicidal Ideation: Analysis of Data from the 15th (2019) Korea Youth Risk Behavior Web-based Survey

Influencing Factors of Dental Hygiene Students College Life Adjustment in COVID-19

벌 화분 (Bee pollen)은 꿀벌이 꿀과 타액 물질로 꽃가루를 뒷다리를 이용하여 응집한 덩어리로, 영양성분이 풍부하며 우수한 항산화 능력을 가진 것으로 보고되었다. 서양종꿀벌이 채집한 벚나무 화분의 에탄올 추출물을 제조하여 항산화 활성을 평가하고자 DPPH 및 ABTS 라디칼 소거능 활성도, FRAP 활성 평가, 총 폴리페놀 및 플라보노이드 함량을 분석하였다. 벚나무 화분 추출물을 농도별 (100, 500, 1,000 μg/mL)로 처리하여 항산화 활성도를 평가한 결과, 처리 농도 중 가장 높은 농도인 1,000 μg/mL에서 DPPH 라디칼 소거능 (41.56%) 및 ABTS 라디칼 소거능 (65.15%)과 FRAP (542.94 μM)로 가장 높게 나타났다. 총 폴리페놀 함량은 58.49 mg GAE/g으로 우수한 함량에 반해 총 플라보노이드는 5.53 mg QE/g 낮은 함량을 보이며 벚나무 화분의 페놀성 화합물은 비플라보노이드 계열 성분들이 대부분 구성하고 있는 것으로 확인하였다. 본 연구 결과를 통해 벚나무 화분의 우수한 항산화 활성도가 확인됨에 따라 벚나무 화분을 건강 기능성 식품 소재로 활용하기 위한 기초 자료로 활용되어 양봉산업의 고부가가치 창출 실현에 이바지할 수 있을 것으로 판단된다. 

Antioxidant Activity of Prunus serrulata var. spontanea Pollen Collected by Apis mellifera

https://www.koreascience.or.kr:443/article/JAKO202118742274049.pdf

Perceptions Types of Workplace Bullying among Clinical Nurses

Systemic inflammation has been proposed as a relevant factor of vascular remodeling and dysfunction. We aimed to identify circulating inflammatory biomarkers that could predict future arteriovenous fistula (AVF) dysfunction in patients undergoing hemodialysis. A total of 282 hemodialysis patients were enrolled in this prospective multicenter cohort study. Plasma cytokine levels were measured at the time of data collection. The primary outcome was the occurrence of AVF stenosis and/or thrombosis requiring percutaneous transluminal angioplasty or surgery within the first year of enrollment. AVF dysfunction occurred in 38 (13.5%) patients during the study period. Plasma interleukin-6 (IL-6) levels were significantly higher in patients with AVF dysfunction than those without. Diabetes mellitus, low systolic blood pressure, and statin use were also associated with AVF dysfunction. The cumulative event rate of AVF dysfunction was the highest in IL-6 tertile 3 (p = 0.05), and patients in tertile 3 were independently associated with an increased risk of AVF dysfunction after multivariable adjustments (adjusted hazard ratio = 3.06, p = 0.015). In conclusion, circulating IL-6 levels are positively associated with the occurrence of incident AVF dysfunction in hemodialysis patients. Our data suggest that IL-6 may help clinicians identify those at high risk of impending AVF failure.

/pdf/plasma-interleukin-6-level-predicts-the-risk-of-1dh2nxee.pdf

Hye Jin Lee

Papers

Predictors of Suicide Attempt among Middle School Students with Suicidal Ideation: Analysis of Data from the 15th (2019) Korea Youth Risk Behavior Web-based Survey

Influencing Factors of Dental Hygiene Students College Life Adjustment in COVID-19

Antioxidant Activity of Prunus serrulata var. spontanea Pollen Collected by Apis mellifera

Perceptions Types of Workplace Bullying among Clinical Nurses

Plasma Interleukin-6 Level Predicts the Risk of Arteriovenous Fistula Dysfunction in Patients Undergoing Maintenance Hemodialysis