Search

The Hong Kong Society of Rheumatology (HKSR) has developed evidence-based position statements on the use of magnetic resonance imaging (MRI) in axial spondyloarthritis (axSpA). A special interest group (SIG) developed the statements based on the literature review of the following research questions: 1) In whom should SI joint MRI be done to diagnose axSpA? 2) Should spine MRI be performed for diagnosis of axSpA? 3) Should spine and SI joint MRI be used in the assessment and monitoring of disease activity? 4) Which MRI sequence(s) should be used in axSpA? These statements have at least 75% agreement from voting rheumatology fellows of HKSR, and are developed to serve as local practice guidelines for rheumatologists and musculoskeletal radiologists in the management of axSpA.

Background: Magnetic resonance imaging (MRI) is important in the management of axial spondyloarthritis (SpA). However, many MRI lesions are not exclusive to axial SpA. Further characterization of these lesions may lead to better clinical decisions. Objective: The objective of this study was to compare the frequency of individual spinal MRI lesions between axial SpA and noninflammatory back pain. The factors associated with individual lesions in participants with axial SpA were also determined. Design: This was a cross-sectional observational study. Methods: MRI lesions in 447 participants with axial SpA and 122 participants with noninflammatory back pain were compared using the propensity score adjustment method. Individual lesions included discovertebral lesions (DVL), Modic type 1 lesions, DVL without Modic type 1 lesions, facet joint lesions, costovertebral joint lesions, corner inflammatory lesions (CIL), and fatty corner lesions (FCL). The factors associated with the lesions were determined using regression analyses. Results: Among participants with axial SpA, 81.9% were HLA-B27-positive, 55.0% had radiographic axial SpA, and 60.5% had radiographic features of spinal damage (mSASSS >2). Almost half (48.6% in axial SpA versus 31.1% in noninflammatory back pain) had inflammatory lesions on spinal MRI. In propensity score matching with noninflammatory back pain, axial SpA had an increased occurrence of DVL without Modic type 1 lesion (OR = 3.43, p = 0.01), costovertebral lesion (OR = 11.89, p = 0.02), number of CIL ( B = 1.19, p

Concept mapping is widely used as a tool for assessing students' understanding of science. To fully realize the diagnostic potential of concept mapping, a scoring method that not only provides an objective and accurate assessment of students' drawn concept maps but also provides a detailed understanding of students' proficiency and deficiencies in knowledge is necessary. However, few of the existing scoring methods focus on the latent constructs (e.g., knowledge, skills, and cognitive processes) that guide the creation of concept maps. Instead, they focus on the completeness of the concept map by assigning a composite score, which makes it difficult to generate targeted diagnostic feedback information for advancing students' learning. To apply the diagnostic classification model to the quantitative analysis of concept maps, this study introduced the novel application of the item expansion-based diagnostic classification analysis (IE-DCA) for this purpose. The IE-DCA can not only assess students' concept mapping abilities along a continuum but also classify students according to their concept mapping attributes when constructing the concept maps. The application and benefits of this approach were illustrated using a physics concept-mapping item related to particle and rigid body. Results showed that the estimated attribute profiles via the IE-DCA provided more detailed information about students' latent constructs than the composite score. Overall, this study illustrates the feasibility and potential of applying IE-DCA to analyze concept maps. Future applications of IE-DCS in other assessments in science education are discussed.

Abstract Background A fatty corner lesion (FCL) is a well-demarcated fat infiltration in the corner of a vertebral body on T1 magnetic resonance imaging (MRI) sequence. It has been reported to be useful in the diagnosis of axial spondyloarthritis (axSpA). Our objective is to systematically evaluate the diagnostic accuracy of FCLs in tertiary centre patients with chronic back pain. Method Two hundred and thirty eight axSpA patients and 62 non-axSpA patients with back pain were recruited from five rheumatology centres. Clinical, biochemical, and radiological parameters were collected and all patients underwent a MRI of the spine and sacroiliac (SI) joints. FCLs in vertebral bodies from C4 to L5 were scored. The number and location of FCLs were clustered together to determine an optimal combination for diagnosis. Results were compared with expert diagnosis as the “gold standard”. Results FCLs of the anterior whole spine (AUC 0.62; p = 0.003) and anterior thoracic spine (AUC 0.64; p = 0.001) had diagnostic significance. Incorporating at least 5 whole spine FCLs into the imaging criteria of the Assessment of SpondyloArthritis international Society (ASAS) criteria for axSpA yielded a sensitivity of 91.6% and specificity of 91.9%. Similarly, applying at least 3 anterior thoracic FCLs to the imaging criteria of the ASAS axial SpA criteria yielded a sensitivity of 92.0% and specificity of 93.5%. Conclusion FCLs could be used to diagnose axial SpA. The presence of at least 3 anterior thoracic FCLs in T1-weighted MRI spine suggests a diagnosis of axial SpA without additional MRI of the SI joints. Trial registration The cohort has been registered in the clinical trial registry of the University of Hong Kong (HKUCTR-2087).

Background: The presence of ⩾3 corner inflammatory lesions has been proposed as the definition of a positive spinal magnetic resonance imaging (MRI) for axial spondyloarthritis (axSpA), but subsequent studies showed inconclusive findings. Our objective was to evaluate whether locations of corner inflammatory lesions (CILs) would affect the diagnostic utility of MRI in axSpA. Method: Two groups were consecutively recruited from eight rheumatology centers in Hong Kong. The ‘axSpA’ group included 369 participants with a known diagnosis of axSpA. The ‘non-specific back pain’ (NSBP) control group consisted of 117 participants. Clinical, biochemical, and radiological parameters were collected and all patients underwent MRI of the spine and sacroiliac joints. CILs were assessed based on their locations (cervical, thoracic or lumbar) to determine the optimal cutoff for diagnosis. Results: The cutoff of ⩾5 whole spine CILs (W-CILs) and ⩾3 thoracic spine CILs (T-CILs) had comparable specificity to MRI sacroiliitis. Of 85/369 axSpA patients without sacroiliitis on conventional radiograph or MRI, 7 had ⩾5 W-CILs and 11 had ⩾3 T-CILs. Incorporating the proposed cutoffs into Assessment of SpondyloArthritis international Society axSpA criteria, ⩾5 W-CILs and ⩾3 T-CILs had similar performance when added to the imaging criteria for sacroiliitis (sensitivity 0.79 versus 0.80, specificity 0.92 versus 0.91). Conclusion: Spinal MRI provided little incremental diagnostic value in unselected axSpA patients. However, in patients without sacroiliitis on MRI or radiographs, 8–13% might be diagnosed by spinal MRI. Thoracic and whole spine MRI had similar diagnostic performance using the proposed cutoff of ⩾5 W-CILs and ⩾3 T-CILs.

OBJECTIVE:To compare the utility of Diffusion weighted imaging (DWI) with short tau inversion recovery (STIR) sequence in the diagnosis of early axial spondyloarthritis (SpA). METHODS:Three hundred and five patients with chronic back pain were recruited consecutively from 3 rheumatology centers. Clinical, radiological and blood parameters were recorded. Patients with back pain duration no more than 3 years were classified as having early disease. STIR sequence and DWI of the sacroiliac joints were obtained and assessed using the Spondyloarthritis Research Consortium of Canada (SPARCC) method. The Assessment in Spondyloarthritis international Society definition was used to define positive STIR and DWI. Results were compared to expert diagnosed axial SpA. RESULTS:When compared to STIR sequence, DWI had similar sensitivity (STIR 0.29, DWI 0.30) and specificity (STIR 0.97, DWI 0.92) in diagnosing sacroiliitis. However, STIR sequence had better reliability (STIR 0.78, DWI 0.61). In early disease group, DWI was not better than STIR sequence in detecting active sacroiliitis (sensitivity DWI vs STIR: 0.34 vs 0.36; specificity DWI vs STIR: 0.93 vs 0.93; positive predictive value DWI vs STIR: 0.92 vs 0.92; negative predictive value DWI vs STIR: 0.36 vs 0.37). Using the Assessment in SpondyloArthritis international Society (ASAS) classification criteria, 67/98 patients with early disease (sensitivity 0.91 specificity 0.90) and 221/305 overall (sensitivity 0.90; specificity 0.92) were classified as axial SpA. Among the expert diagnosed axial SpA patients who did not meet the ASAS criteria, only 2 had positive DWI. CONCLUSION:DWI and STIR have similar sensitivity in diagnosing axSpA in early disease. However, the use of DWI is limited by poorer reliability when compared with STIR.

As more and more science teacher educators are subscribing to a practice-based teacher education curriculum, it is becoming increasingly necessary to identify and articulate smaller grain-sized teaching practices nested within a core practice in important instructional contexts in order to facilitate preservice science teachers' (PSTs') learning of core practices. This paper illustrates how to achieve this goal using data from a qualitative study that aimed to characterize how PSTs enact the core practice of eliciting and working with student thinking in the three key stages of collaborative group work in rehearsals: whole-class warm-up, small group work, and whole-class share-out. Based on existing teaching practices synthesized from prior studies, as well as empirical data from the study, we identify the intermediate-level practices (teaching moves) and technique-level practices (talk moves) enacted by PSTs when orchestrating group work as well as the PSTs' strengths and missed opportunities in enacting these different grain-sized practices. Findings reveal that, although the PSTs were able to enact a variety of talk moves when orchestrating group work, they missed opportunities to engage in intermediate-level practices. For example, there were only a few instances in which the PSTs could explicitly work with the student thinking they noticed while circulating among the groups during whole-class share-out. We also identify three ways in which the PSTs used this intermediate-level practice, reflective of their differing orientations toward using student thinking. We propose an integrative framework that decomposes the focal core practice into a nested set of practices of varying grain sizes, including medium grain-sized teaching moves and small grain-sized talk moves, during and across the key stages of group work. We discuss the implications of our findings for science teacher preparation and methodological approaches for capturing PSTs' enactment of the focal core practice, as well as the possible contributions of the framework.

Pedagogical content knowledge (PCK) is an important target of science teacher knowledge assessment. Most studies that have assessed the PCK across a large sample of science teachers used a text-based approach to elicit and assess the more declarative and static form of teachers' PCK. Recently, small-scale qualitative studies have adopted a novel video-based approach to characterize the more situated and dynamic form of PCK underpinning a teacher's in-the-moment pedagogical reasoning. In this relatively large-scale mixed-methods study, these two approaches to assessing PCK were compared. Specifically, a counterbalanced design was adopted to compare the test scores of 147 Grade 7 biology teachers in a video-based PCK test with those of the same teachers in a text-based PCK test with the same content. A subgroup of teachers (N = 30) with different levels of PCK was interviewed to further understand their reactions to the test and how these might have affected their test performance. The results of paired-samples t tests showed that the teachers' PCK scores in the two types of test were significantly correlated, but their scores were significantly lower in the video-based test. In terms of teacher reactions, although the teachers considered both types of test to be fair, they regarded the video-based test as more authentic and more closely related to their job demands. The teachers reported putting more effort into the video-based test and feeling more immersed and engaged, but also experiencing greater cognitive demand and a higher level of anxiety. A multiple regression analysis revealed that the cognitive demand perceived by the teachers significantly predicted their PCK scores in the video-based test. The findings have implications for the valid design of video-based PCK tests.

Background: Effective science teaching requires a specialised body of knowledge. Researchers have recognised the importance of understanding the incoming knowledge that pre-service science teachers (PSTs) bring to their initial teacher education. However, although many studies have focused on PSTs' declarative knowledge or the knowledge that informs their lesson planning decisions, few have considered the knowledge that PSTs activate and use in contexts similar to authentic classroom situations. Purpose: This study investigated the nature of PSTs' incoming "usable knowledge" for teaching science. Specifically, it utilised two video-based tasks, a video annotation task and an interactive video analysis task, to explore and characterise the nature of two forms of usable knowledge: knowledge that informs PSTs' analysis of classroom situations and knowledge that informs their in-the-moment instructional decision-making. usable knowledge Methods: Fourteen PSTs attempted two video-based tasks at the beginning of a science major methods course. Their responses in the two tasks were analysed qualitatively to shed light on the two abovementioned forms of usable knowledge. Findings: The PSTs readily identified the general pedagogical knowledge (PK) and topic-specific pedagogical content knowledge (PCK), but not the discipline-specific PCK displayed by the teacher shown in the videos. Second, the PSTs readily identified examples of students' non-cognitive engagement or content-generic thinking in the videos. The PSTs tended to describe rather than activate their knowledge of student understanding to interpret the examples of students' cognitive thinking identified in the videos. Third, the PSTs relied primarily on PK, not PCK, to suggest alternative instructional strategies/representations. Finally, the PSTs' responses were seldom connected with emergent student thinking; instead, PSTs relied on PK rather than PCK in their on-the-fly teaching decisions. Conclusion: The study delineated two forms of PSTs' usable knowledge for teaching science and exemplified how video-based instruments can be used to systematically investigate teachers' usable knowledge for teaching science.

Pedagogical content knowledge (PCK) refers to the content-specific knowledge that teachers use to promote students' learning of specific subject matter. PCK comprises multiple knowledge components that interact with each other when enacted in teachers' instructional practices. For many years, researchers lacked a robust methodological approach to unpack the structure and organisation of science teachers' PCK. In 2012, Park and Chen developed the PCK map approach to identify, quantify and visualise the complex interactions between PCK components that shape the instructional practices of science teachers. After a systematic literature search, we identified 22 studies from eleven geographical regions that used the PCK map approach to analyse the integration of science teachers' PCK components. An in-depth analysis of how the PCK map approach has been used, adapted and refined in these studies was performed. Findings reveal that some studies modified this approach in ways that did not retain the methodological strengths and robustness inherent in its original formulation. Some conflicting findings about the nature of the integration between PCK components are evident in the studies reviewed as well as in the broader literature on science teachers' knowledge. Issues related to the use of the PCK map approach and recommendations on how to use this approach to investigate science teachers' PCK are discussed.

Learning science encompasses learning the language of science, which can pose considerable challenges to students due to its specialized features and structures. Addressing the three-language problem (the need to transition between daily, general school and disciplinary languages) and the specific language demands of science thus constitutes part of the larger goal of promoting disciplinary literacy. Most studies have focused on the conceptual demands of science learning and have not examined what knowledge teachers require to support students' learning of the language of science. In this study, we focus on science teachers' knowledge of students (KS) for addressing the language demands of science. This qualitative case study has two aims: (1) to unpack a teacher's KS related to their language use in science and (2) to uncover how this KS informs teaching practices. Transcripts of teacher interviews, lesson planning sessions and lessons drawn from two Grade 4 science classrooms taught by a primary science teacher constituted the data for this study. We identify five aspects of KS (i.e. prior knowledge of and about language, difficulties with language, abilities across modes of language and across subject areas and learning progress) that inform four distinct teaching practices. This case study highlights and unpacks a dimension of KS that is often overlooked in the current literature on pedagogical content knowledge (PCK) for science teaching. The implications to teachers' PCK, science teaching and teacher professional development are discussed in light of the findings.

This study investigated the nature of pre-service science teachers' (PSTs') situation-specific skills for informal formative assessment (FA) and their awareness of activating these skills in classroom-like situations. Video-based interviews were conducted to collect data from fifteen PSTs before they participated in a teacher education program. Authentic classroom videos capturing evidence of student thinking were used as probes to elicit information on the PSTs' perceptions, interpretations, and decision-making in various classroom-like situations that afforded opportunities for FA. The findings indicate that the PSTs tended to focus on content-generic evidence and the responses of students in the whole class, to infer student thinking at a non-content specific level, and to propose responses that were vague or devoid of scientific content. On re-exposure to the same evidence of student thinking captured in short video clips, and with more specific prompting questions, more of the PSTs identified content-specific evidence from individual students and interpreted the nuances of student thinking at a content-specific level. Yet, the capacity of the PSTs to propose student-focused instructional moves remained limited. Overall, the findings suggest that the PSTs were not particularly aware of applying their situation-specific skills for informal FA when making on-the-fly teaching decisions in classroom-like situations that offer rich opportunities for FA. This study adds to the existing understanding of PST knowledge/skills for informal FA and provides a mechanism for eliciting and characterizing teachers' situation-specific skills for informal FA. The implications for initial teacher education are discussed.

Student teachers (STs) were asked to reflect on their experiences of watching videos of their own and their peers' teaching and to generate and share metaphors of the experience. Qualitative analysis of their metaphorical explanations revealed the cognitive, emotional and motivational responses associated with the STs' video-viewing experiences. The STs reported a tendency to focus on the teacher-in-the-video in both types of video. They were more evaluative in their comments and experienced more negative emotions when watching videos of themselves. Some said they had adopted an overly critical and fault-finding attitude when watching themselves. Conversely, viewing videos of their peers was more likely to elicit positive emotions, greater involvement and more engagement. The implications of using metaphor to understand and foster reflection on STs' video-viewing experiences with different types of video are discussed.

In recent years, teacher noticing has emerged as a construct to capture the dynamic and situational aspects of teaching expertise that underlies teachers' in-the-moment teaching decisions and actions. In mathematics education research, in particular, teacher noticing has been studied to understand how teachers attend to, and make sense of, students' mathematical thinking and reasoning. This construct has recently found its way into the science education literature. This paper reviews how the construct of teacher noticing has been understood and empirically investigated in the science education literature. We reviewed 29 empirical studies that focused on science teachers' noticing and analysed how teacher noticing was defined and conceptualised in terms of its constituent components in these studies as well as the range of approaches used to investigate teacher noticing. Our analysis highlights how the original understanding of, and underlying assumptions about, teacher noticing have shifted as the construct has been imported into the science education literature. This review raises issues related to the investigation of teacher noticing and discusses how the findings of these studies can advance our existing knowledge of science teaching expertise. Finally, we propose directions for future research in this emerging field of research.

Students need procedural understanding--that is, knowledge of the procedures that scientists use to establish scientific evidence (also known as "concepts of evidence"), to successfully perform scientific investigations, and to evaluate public and scientific claims. However, concepts of evidence are seldom explicitly targeted in routine practical activities in secondary school science classrooms. We describe how a commonly used practical activity, yeast fermentation, can be modified to provide a meaningful context for developing students' understanding of concepts of evidence associated with measurement, as well as more difficult-to-learn scientific ideas, such as rates of reaction. The modified practical activities give students opportunities to exercise their creativity in assembling setups; brainstorm solutions to design problems in teams; reflect on their decisions related to concepts of evidence associated with measurement when designing their setups; compare the validity and reliability of data produced using different setups; and develop their understanding of difficult-to-learn scientific ideas.

Although empirical studies have consistently indicated that students commonly struggle to learn and understand the concepts related to reflex actions, few teaching strategies have been developed that specifically address these learning difficulties. This article introduces simple teaching models that simulate the nervous pathways related to the human withdrawal reflex. We show how these models may be used to engage students in active learning about these nervous pathways. The proposed models and the activities are useful resources for enabling secondary school students to gain conceptual understanding of the withdrawal reflex.

ABSTRACT Cultivating in preservice science teachers (PSTs) the competence required to teach scientific models and modeling is a valued outcome of teacher preparation programs. However, science teacher educators face inherent tensions when designing and implementing teacher preparation experiences to achieve this outcome. In this systematic review, we first propose five sets of design tensions that science teacher educators need to navigate. We identify empirical intervention studies that aimed to develop PSTs' professional competence for teaching scientific models and modeling and analyze how the reviewed interventions addressed the design tensions, and examine their outcomes. Our analysis reveals that the reviewed interventions prioritized the development of PSTs' cognitive aspects of teacher professional competence for teaching scientific models and modeling while giving limited attention to affective–motivational aspects and the need to simultaneously develop aspects of PSTs' competence not specific to scientific models and modeling. The interventions were more successful in enhancing PSTs' declarative knowledge than enacted knowledge and affective–motivational aspects. However, the nature of modeling activities included in the interventions varied widely, posing challenges in identifying critical features that led to the identified positive outcomes. The interventions reported mixed outcomes in developing PSTs' enacted knowledge in teaching contexts, even when incorporating activities for knowledge application and knowledge transfer beyond the intervention context. We discuss the implications of these findings and provide recommendations for better‐preparing PSTs to teach scientific models and modeling. We also discuss the unique affordance of using the design tension framework to analyze the interventions. [ABSTRACT FROM AUTHOR]

Concept mapping is widely used as a tool for assessing students' understanding of science. To fully realize the diagnostic potential of concept mapping, a scoring method that not only provides an objective and accurate assessment of students' drawn concept maps but also provides a detailed understanding of students' proficiency and deficiencies in knowledge is necessary. However, few of the existing scoring methods focus on the latent constructs (e.g., knowledge, skills, and cognitive processes) that guide the creation of concept maps. Instead, they focus on the completeness of the concept map by assigning a composite score, which makes it difficult to generate targeted diagnostic feedback information for advancing students' learning. To apply the diagnostic classification model to the quantitative analysis of concept maps, this study introduced the novel application of the item expansion‐based diagnostic classification analysis (IE‐DCA) for this purpose. The IE‐DCA can not only assess students' concept mapping abilities along a continuum but also classify students according to their concept mapping attributes when constructing the concept maps. The application and benefits of this approach were illustrated using a physics concept‐mapping item related to particle and rigid body. Results showed that the estimated attribute profiles via the IE‐DCA provided more detailed information about students' latent constructs than the composite score. Overall, this study illustrates the feasibility and potential of applying IE‐DCA to analyze concept maps. Future applications of IE‐DCS in other assessments in science education are discussed. [ABSTRACT FROM AUTHOR]

Evidence of student thinking takes a variety of forms (e.g. verbal responses, gestures) and has varying degrees of visibility within classroom interactions. The purpose of this study was to characterise the nature of pre-service science teachers' (PSTs') noticing skills of different forms of evidence of student thinking using video-based interviews. In the interviews, the PSTs were asked to describe what they had noticed in the videos that captured different forms of evidence of student thinking and 'think on their feet' to propose the next instructional moves as if they were the teacher. The PSTs' comments on the videos were analysed qualitatively with respect to the forms of evidence they noticed and how they interpreted and responded to the evidence. Several findings regarding the nature of PSTs' noticing skills were uncovered. First, the PSTs readily identified non-verbal forms of evidence, such as voting and student actions. However, some forms of evidence that potentially reveal the content of student thought, such as student artefacts, questions and verbal explanations, were less visible to the PSTs. Second, the PSTs used the identified evidence to infer student engagement levels, attributes and understanding and were generally able to propose instructional responses based on the student thinking that they had identified. Third, the findings also suggest that when the PSTs paid attention to the details of the evidence, they were more likely to connect their instructional decisions to student understanding at a content-specific level. The implications for research on PSTs' noticing and initial education are discussed.

Teaching experience has been identified as an important factor in pedagogical content knowledge (PCK) development. However, little is known about "how" experienced teachers may draw on their previous experience to facilitate their PCK development. This study examined how two experienced high school biology teachers approached the teaching of a newly introduced topic in the curriculum, polymerase chain reaction and their PCK development from the pre-lesson planning phase through the interactive phase to the post-lesson reflection phase. Multiple data sources included classroom observations, field notes, semi-structured interviews and classroom artefacts. It was found that the teachers' previous experience informed their planning for teaching the new topic, but in qualitatively different ways. This, in turn, had a bearing on their new PCK development. Subject matter knowledge (SMK) can not only facilitate but may also hinder this development. Our findings identify two types of experienced teachers: those who can capitalise on their previous teaching experiences and SMK to develop new PCK and those who do not. The critical difference is whether in the lesson planning stage, the teacher shows the disposition to draw on a generalised mental framework that enables the teacher to capitalise on his existing SMK to develop new PCK. Helping teachers to acquire this disposition should be a focus for teacher training in light of continuous curriculum changes.

Existing laboratory protocols for investigating the effects of factors affecting enzyme activity often require extensive hands-on manipulations and time. This can result in students either not getting the desired results or being distracted from thinking about the scientific ideas underlying the experimental designs and procedures of these protocols. In this paper, we present a lesson plan that includes a simple microscale laboratory protocol that allows students to study the action of amylase on starch and to investigate the effects of various factors (i.e., temperature, pH, substrate concentration, enzyme concentration, and competitive reversible inhibitors) on enzyme activity using immobilized amylase beads. We also show how to engage students in thinking about procedural knowledge, such as repeating measurements, measurement range, and interval. These concepts are critical to designing valid and reliable scientific investigations. [ABSTRACT FROM AUTHOR]

Structural genomics consortia established that protein crystallization is the primary obstacle to structure determination using x‐ray crystallography. We previously demonstrated that crystallization propensity is systematically related to primary sequence, and we subsequently performed computational analyses showing that arginine is the most overrepresented amino acid in crystal‐packing interfaces in the Protein Data Bank. Given the similar physicochemical characteristics of arginine and lysine, we hypothesized that multiple lysine‐to‐arginine (KR) substitutions should improve crystallization. To test this hypothesis, we developed software that ranks lysine sites in a target protein based on the redundancy‐corrected KR substitution frequency in homologs. This software can be run interactively on the worldwide web at https://www.pxengineering.org/. We demonstrate that three unrelated single‐domain proteins can tolerate 5–11 KR substitutions with at most minor destabilization, and, for two of these three proteins, the construct with the largest number of KR substitutions exhibits significantly enhanced crystallization propensity. This approach rapidly produced a 1.9 Å crystal structure of a human protein domain refractory to crystallization with its native sequence. Structures from Bulk KR‐substituted domains show the engineered arginine residues frequently make hydrogen‐bonds across crystal‐packing interfaces. We thus demonstrate that Bulk KR substitution represents a rational and efficient method for probabilistic engineering of protein surface properties to improve crystallization. [ABSTRACT FROM AUTHOR]

The analysis of exemplars is a potentially powerful way of acquainting students with academic standards and supporting their capacities to make informed academic judgements. This paper investigates the role of dialogue in supporting students to develop their appreciation of the nature of quality work. The research derives from a project involving nine teachers in a Faculty of Education, and uses data from a single case to analyse the dialogic use of exemplars. The findings illustrate how the teacher prioritised student talk and withheld his own evaluative judgements in the management of the discussion. A related dilemma lies in the balance between the student voice in constructing their views on the nature of quality and explicit teacher guidance. The main significance of the paper lies in its description of how exemplars dialogue can be orchestrated, and a discussion of some of the main features of the dialogue.

Designing classroom assessment tasks that can gather meaningful assessment information is a complex undertaking. This is especially the case when it comes to developing assessment tasks to evaluate students' abilities to plan scientific investigations. Such assessment tasks should adequately elicit students' cognitive understandings related to designing valid and reliable experiments, not just their hands-on manipulative skills. This article proposes a set of guidelines for developing written assessment tasks that can surface students' cognitive understandings related to planning scientific investigations. We show how the checklist created based on the design guidelines can be used to analyze two classroom assessment tasks. The guidelines will be useful for teachers as they develop new or modify existing classroom assessment tasks to meaningfully evaluate students' abilities to plan scientific investigations. [ABSTRACT FROM AUTHOR]