Surgical methods of contraception and sterilization

Many techniques for surgically sterilizing dogs and cats have been described; each technique offers advantages and disadvantages to both the patient and surgeon. Techniques that have been described include traditional midline ovariohysterectomy, lateral flank ovariohysterectomy, castration, early age gonadectomy, ovariectomy, laparoscopic ovariohysterectomy and ovariectomy, and vasectomy. Regardless of the technique selected, strict adherence to sound surgical technique and asepsis is mandatory for good surgical outcome with minimal complications. This review will discuss surgical principles, complications, outcomes, as well as relevant current literature associated with each of these techniques of surgical sterilization.     

A resource for understanding and evaluating outcomes of undergraduate field experiences

Undergraduate field experiences (UFEs) are a prominent element of science education across many disciplines; however, empirical data regarding the outcomes are often limited. UFEs are unique in that they typically take place in a field setting, are often interdisciplinary, and include diverse students. UFEs range from courses, to field trips, to residential research experiences, and thereby have the potential to yield a plethora of outcomes for undergraduate participants. The UFE community has expressed interest in better understanding how to assess the outcomes of UFEs. In response, we developed a guide for practitioners to use when assessing their UFE that promotes an evidence‐based, systematic, iterative approach. This essay guides practitioners through the steps of: identifying intended UFE outcomes, considering contextual factors, determining an assessment approach, and using the information gained to inform next steps. We provide a table of common learning outcomes with aligned assessment tools, and vignettes to illustrate using the assessment guide. We aim to support comprehensive, informed assessment of UFEs, thus leading to more inclusive and reflective UFE design, and ultimately improved student outcomes. We urge practitioners to move toward evidence‐based advocacy for continued support of UFEs.     

Ecology and the War on Hunger

This interdisciplinary activity promotes science, technology, and language arts and is well suited for upper elementary grade students. In the activity, students' research about a teacher-assigned weather phenomenon facilitates their study of the weather. When they have completed their research, students word process a paper summarizing their findings and generate graphical representations of a weather phenomenon using Microsoft Paint software. The paper and the computer-generated graphical representation measure learning and provide insight into the level of student understanding that other assessment tools, such as quizzes, tests, and questioning techniques, do not provide.     

Students' motivations for data handling choices and behaviors: their explanations of performance

Cries for increased accountability through additional assessment are heard throughout the educational arena. However, as demonstrated in this study, to make a valid assessment of teaching and learning effectiveness, educators must determine not only what students do, but also why they do it, as the latter significantly affects the former. This study describes and analyzes 14- to 16-year-old students' explanations for their choices and performances during science data handling tasks. The study draws heavily on case-study methods for the purpose of seeking an in-depth understanding of classroom processes in an English comprehensive school. During semistructured scheduled and impromptu interviews, students were asked to describe, explain, and justify the work they did with data during their science classes. These student explanations fall within six categories, labeled 1) implementing correct procedures, 2) following instructions, 3) earning marks, 4) doing what is easy, 5) acting automatically, and 6) working within limits. Each category is associated with distinct outcomes for learning and assessment, with some motivations resulting in inflated performances while others mean that learning was underrepresented. These findings illuminate the complexity of student academic choices and behaviors as mediated by an array of motivations, casting doubt on the current understanding of student performance.     

城市热环境定量评价技术研究进展及发展趋势

自“城市热岛”概念提出以来,城市热环境定量评价一直是城市气候与环境研究领域的重要内容.随着空间信息技术与计算机模拟技术的不断发展,城市热环境定量评价的技术手段和方法也取得了长足进步.从最初单一利用气象站历史数据对城市宏观尺度热环境进行数理统计分析,逐步发展到综合利用地面气象观测、热红外遥感、数值模式模拟等多种技术对不同尺度热环境进行动态模拟与预测.本文系统回顾了地面气象观测、热红外遥感、数值模式模拟3类城市热环境定量评价技术的发展历程,并总结了各类技术的优缺点、适用性及发展趋势,以期为今后的城市热环境评价与优化研究提供参考.     

医院综合绩效考核体系的构建与实施

医院综合绩效考核体系包括成本核算办法、平衡计分卡绩效考核、千分制质控考核、年度绩效考核、单项奖等方面,介绍和分析了各种绩效考核办法及其利弊。构建医院综合绩效考核体系,可以相互扬长避短,兼顾多个方面,促进医院又好又快发展。     

Foundations of form and function: A synthesis‐based curriculum for introductory‐level organismal biology

First‐year majors organismal biology courses are frequently taught as survey courses that promote memorization rather than synthesis of biological concepts. To address the shortcomings of this approach, we redesigned the organismal portion of our introductory biology curriculum to create a “Foundations of Form and Function” course. Foundations of Form and Function introduces different organismal forms and focuses on the relationship between those forms and the execution of key physiological functions. Goals of our new course include the following: developing student recognition of common characteristics that unite living organisms as well as features that distinguish taxonomic groups, facilitating student understanding of how organisms accomplish similar functions through different forms, and reinforcing course themes with independent student research. In this paper, we describe course learning outcomes, organization, content, assessment, and laboratory activities. We also present student perspectives and outcomes of our course design based on data from four years of student evaluations. Finally, we explain how we modified our course to meet remote learning and social‐distancing challenges presented by the COVID‐19 pandemic in 2020 and 2021.     

Subtraction-coupled custom microarray analysis for gene discovery and gene expression studies in the CNS

The revolution in our knowledge about the genomes of organisms gives rise to the question, what do we do with this information? The development of techniques allowing high throughput analysis of RNA and protein expression, such as cDNA microarrays, provide for genome-wide analysis of gene expression. These analyses will help bridge the gap between systems and molecular neuroscience. This review discusses the advantages of using a subtractive hybridization technique, such as a representational difference analysis, to generate a custom cDNA microarray enriched for genes relevant to investigating complex, heterogeneous tissues such as those involved in the chemical senses. Real and hypothetical examples of these experiments are discussed. Benefits of this approach over traditional microarray techniques include having a more relevant clone set, the potential for gene discovery and the creation of a new tool to investigate similar systems. Potential pitfalls may include PCR artifacts and the need for sequencing. However, these disadvantages can be overcome so that the coupling of subtraction techniques to microarray screening can be a fruitful approach to a variety of experimental systems.     

Practical approaches to plant volatile analysis

Plants emit volatile organic compounds (VOCs) that play important roles in their interaction with the environment and have a major impact on atmospheric chemistry. The development of static and dynamic techniques for headspace collection of volatiles in combination with gas chromatography-mass spectrometry analysis has significantly improved our understanding of the biosynthesis and ecology of plant VOCs. Advances in automated analysis of VOCs have allowed the monitoring of fast changes in VOC emissions and facilitated in vivo studies of VOC biosynthesis. This review presents an overview of methods for the analysis of plant VOCs, including their advantages and disadvantages, with a focus on the latest technical developments. It provides guidance on how to select appropriate instrumentation and protocols for biochemical, physiological and ecologically relevant applications. These include headspace analyses of plant VOCs emitted by the whole organism, organs or enzymes as well as advanced on-line analysis methods for simultaneous measurements of VOC emissions with other physiological parameters.     

The development of computer simulations of the geometries and thermodynamics of biological molecules

The historical development of computer simulations of molecular geometry and thermodynamics (molecular mechanics, force field method) is outlined. The advantages and disadvantages of techniques such as energy minimization, molecular dynamics and free energy perturbation are discussed. An example is included that shows how energy minimization studies of dopamine D-2 antagonists have been used to develop an understanding of the three-dimensional pharmacophore necessary for this pharmacological activity.     

Neurotoxicology: principles and considerations of in vitro assessment

Neurotoxicology is an exciting area of science, not only because of the importance of toxic injury to the nervous system in human disease, but also because specific toxicants have served as invaluable tools for the advancement of our knowledge of "normal" neurobiological processes. In fact, much of our understanding of the organisation and function of the nervous system is based on observations derived from the actions of neurotoxicants. This paper addresses various physiological aspects behind the exquisite sensitivity of the nervous system to toxic agents, including the privileged status of the nervous system vis-a-vis blood-brain barrier function, the extensions of the nervous system over space and the requirements of cells with such a complex geometry, and the transmission of information across extracellular space. In addition, in vitro models and their utility in the assessment of neurotoxicological outcome are discussed, with reference to both their advantages and disadvantages.     

In situ analysis of metal(loid)s in plants: State of the art and artefacts

Metals and metalloids play important roles in plant function and metabolism. Likewise, plants subsequently introduce vital dietary nutrition to people and animals. Understanding the transport, localisation and speciation of these elements is critical for understanding availability and metabolic pathways. Subsequently this knowledge can be applied to plant physiology and agricultural research, food science and genetic engineering.This review focuses on the most recent status of in situ techniques to visualise spatial distributions and assess the speciation of metals and metalloids. The techniques addressed include: histochemical analysis, autoradiography, LA-ICP-MS, SIMS, SEM including EDX, PIXE; and synchrotron methods: XRF, differential and fluorescence tomography, and X-ray absorption techniques.This review has been written with the intent of plant researchers to gain familiarity with techniques to which they are not accustom but wish to extend their research with alternative, but complementary, capabilities. Importantly, the disadvantages as well as advantages, have been highlighted for each technique and potential artefacts induced by the analysis or sample preparation are reviewed. These often overlooked aspects are the points critical for novice use of unfamiliar techniques and are offered for advancing research approaches commensurate with the accelerating interest regarding metal(loid)s in botanical specimens.     

Monitoring and screening plant populations with combined thermal and chlorophyll fluorescence imaging

Thermal and chlorophyll fluorescence imaging are powerful tools for the study of spatial and temporal heterogeneity of leaf transpiration and photosynthetic performance. The relative advantages and disadvantages of these techniques are discussed. When combined, they can highlight pre-symptomatic responses not yet apparent in visual spectrum images and provide specific signatures for diagnosis of distinct diseases and abiotic stresses. In addition, their use for diagnosis and for selection for stomatal or photosynthetic mutants, these techniques can be applied for stress tolerance screening. For example, rapid screening for stomatal responses can be achieved by thermal imaging, while, combined with fluorescence imaging to study photosynthesis, they can potentially be used to derive leaf water use efficiency as a screening parameter. A particular advantage of imaging is that it allows continuous automated monitoring of dynamic spatial variation. Examples of applications include the study of growth and development of plant lines differing in stress resistance, yield, circadian clock-controlled responses, and the possible interactions between these parameters. In the future, such dual-imaging systems could be extended with complementary techniques such as hyperspectral and blue-green fluorescence imaging. This would result in an increased number of quantified parameters which will increase the power of stress diagnosis and the potential for screening of stress-tolerant genotypes.     

鼻咽癌的放射治疗技术探究

目的:通过比较鼻咽癌放射治疗的不同技术方法,了解其优势及不同点,以期找到更有效并切合实际的技术方法,提高鼻咽癌的放疗技术水平。方法:常规外照射技术;等中心整体挡铅技术;三维适形放射治疗技术。结果:三种技术方法各具优缺点,结论:三维适形放射治疗技术最具优势,但设备和技术要求高;常规外照射技术经济实用,技术稳定性较差;等中心整体挡铅技术质量稳定。     

Studying Gene Expression System Regulation at the Program Level

Understanding how gene expression systems influence biological outcomes is an important goal for diverse areas of research. Gene expression profiling allows for the simultaneous measurement of expression levels for thousands of genes and the opportunity to use this information to increase biological understanding. Yet, the best way to relate this immense amount of information to biological outcomes is far from clear. Here, a novel approach to gene expression systems research is presented that focuses on understanding gene expression systems at the level of gene expression program regulation. It is suggested that such an approach has important advantages over current techniques and may provide novel insights into how gene expression systems are regulated to shape biological outcomes such as the development of disease or response to treatment.     

Vesicle reconstitution from lipid-detergent mixed micelles

The process of formation of lipid vesicles using the technique of detergent removal from mixed-micelles is examined. Recent studies on the solubilization and reconstitution of liposomes participated to our knowledge of the structure and properties of mixed lipid-detergent systems. The mechanisms involved in both the lipid self assembly and the micelle-vesicle transition are first reviewed. The simplistic three step minimum scheme is described and criticized in relation with isothermal as well as a function of the [det]/[lip] ratio, phase diagram explorations. The techniques of detergent elimination are reviewed and criticized for advantages and disadvantages. New methods inducing micelle-vesicle transition using enzymatic reaction and T-jump are also described and compared to more classical ones. Future developments of these techniques and improvements resulting of their combinations are also considered. Proper reconstitution of membrane constituents such as proteins and drugs into liposomes are examined in the light of our actual understanding of the micelle-vesicle transition.     

Advances in magnetic resonance imaging of lung physiology.

This review presents an overview of some recent magnetic resonance imaging (MRI) techniques for measuring aspects of local physiology in the lung. MRI is noninvasive, relatively high resolution, and does not expose subjects to ionizing radiation. Conventional MRI of the lung suffers from low signal intensity caused by the low proton density and the large degree of microscopic field inhomogeneity that degrades the magnetic resonance signal and interferes with image acquisition. However, in recent years, there have been rapid advances in both hardware and software design, allowing these difficulties to be minimized. This review focuses on some newer techniques that measure regional perfusion, ventilation, gas diffusion, ventilation-to-perfusion ratio, partial pressure of oxygen, and lung water. These techniques include contrast-enhanced and arterial spin-labeling techniques for measuring perfusion, hyperpolarized gas techniques for measuring regional ventilation, and apparent diffusion coefficient and multiecho and gradient echo techniques for measuring proton density and lung water. Some of the major advantages and disadvantages of each technique are discussed. In addition, some of the physiological issues associated with making measurements are discussed, along with strategies for understanding large and complex data sets.     

A brief history of genetic variation analysis

As the human genome sequence is determined, there is an emerging need for the analysis of human sequence variations as genetic markers in diagnosis, linkage and association studies, cancer research, and pharmacogenomics. There are several different techniques and approaches for detecting these genetic variations, and here we review some of these techniques and their application fields. However, all the techniques have advantages and disadvantages, andfactors such as laboratory instrumentation, personnel experience, required accuracy, required throughput, and cost often have to be taken into account before selecting a method.     

Small intestinal manometry

Gastrointestinal motility is an integrated process including myoelectrical and contractile activity, tone, compliance and transit. The techniques for the assessment of gastrointestinal motility are multiple and all have their advantages and disadvantages. In the case of suspected abnormal upper gut transit, gastric and small bowel transit scintigraphy followed by small intestinal (antroduodenojejunalileal) manometry is recommended. Small bowel manometry can identify patterns suggestive of myopathy, neuropathy or obstruction. Information on procedures, indications, significance, pitfalls and guidelines for small bowel manometry is provided in this paper. In this context the potentials of small intestinal manometry for scientific experimental study of neurohumoral agents, such as serotonin receptor agonists and antagonists, on small intestinal motility is presented.