Physical Chemistry Lab for Data Analysis of COVID-19 Spreading Kinetics in Different Countries.

The COVID-19 pandemic has passed. It gives us a real-world example of kinetic data analysis practice for our undergraduate physical chemistry laboratory class. It is a great example to connect this seemingly very different problem to the kinetic theories for chemical reactions that the students have learned in the lecture class. At the beginning of the spring 2023 semester, we obtained COVID-19 kinetic data from the "Our World in Data" database, which summarizes the World Health Organization (WHO) data reported from different countries. We analyzed the effective spreading kinetics based on the susceptible-infectious-recovered-vaccinated (SIR-V) model. We then compared the effective rate constants represented by the real-time reproduction numbers ( R t ) underlining the reported data for these countries and discussed the results and the limitations of the model with the students.

Staging the Tumor and Staging the Host: Pretreatment Combined Neutrophil Lymphocyte Ratio and Modified Glasgow Prognostic Score Is Associated with Overall Survival in Patients with Esophagogastric Cancers Undergoing Treatment with Curative Intent.

BACKGROUND: This study examined whether an innate systemic inflammatory response (SIR) measured by combination neutrophil to lymphocyte ratio (NLR) and modified Glasgow Prognostic Score (mGPS) was associated with overall survival (OS) in patients with esophagogastric cancer (EC) undergoing neoadjuvant chemotherapy (NAC) followed by surgery. METHODS: Patients diagnosed with EC, managed with NAC prior to surgery at a regional referral center, between January 2010 and December 2015, were included. The mGPS and NLR were calculated within 12 weeks before NAC. Patients were grouped by combined NLR/mGPS score into three groups of increasing SIR: NLR ≤ 3 (n = 152), NLR > 3 + mGPS = 0 (n = 55), and NLR > 3 + mGPS > 0 (n = 32). Univariable and multivariable Cox regression was used to analyse OS. RESULTS: Overall, 337 NAC patients were included, with 301 (89%) proceeding to surgery and 215 (64%) having R0 resection. There were 203 deaths, with a median follow-up of those alive at censor of 69 months (range 44-114). Higher combined NLR/mGPS score (n = 239) was associated with poorer OS independent of clinical stage and performance status (hazard ratio 1.28, 95% confidence interval 1.02-1.61; p = 0.032), higher rate of progression on NAC (7% vs. 7% vs. 19%; p = 0.003), and lower proportion of eventual resection (80% vs. 84% vs. 53%; p = 0.003). CONCLUSIONS: The combined NLR/mGPS score was associated with OS and initial treatment outcomes in patients undergoing NAC prior to surgery for EC, stratifying survival in addition to clinical staging and performance status. The host SIR may be a useful adjunct to multidisciplinary decision making.

Effects of the source gap on transmission efficiency of a quadrupole mass spectrometer.

RATIONALE: Recent trends towards miniature and portable quadrupole mass spectrometry (QMS) entail challenges in instrumental sensitivity, which is influenced by 3D fringe field effects on ion transmission in the Quadrupole Mass Filter (QMF). The relationship of these effects with the gap from the ion source to the QMF entrance (source gap) is significant and little explored. We examine transmission characteristics experimentally and use the results to test the predictive accuracy of a recently developed 3D QMF simulation model. The model is then applied to directly investigate optimal transmission m/z ranges across multiple source gaps. METHODS: A portable single filter quadrupole mass spectrometer is used to analyse transmission characteristics across a range of common gases. We use an experimental approach originally proposed by Ehlert, enhanced with a novel method for absolute calibration of the transmission curve. Custom QMF simulation software employs the boundary element method (BEM) to compute accurate 3D electric fields. This is used to study the effects of the source gap on transmission efficiency. RESULTS: Experimental findings confirm a centrally peaked transmission curve; simulations correctly predict the optimal transmission location (in m/z) and percentage, and extend the experimental trend. We compare several methods for determining fringe field length, demonstrating how the size of the physical source gap influences both the length and the intensity of the fringe field at the QMF entrance. A complex relationship with ion transmission is revealed in which different source gaps promote optimal transmission at differing m/z ranges. CONCLUSIONS: The presented results map the relationship between the source gap and transmission efficiency for the given instrument, using a simulation method transferrable to other setups. This is of importance to miniature and portable quadrupole mass spectrometers design for specific applications, for the first time enabling the source gap to be tailored for optimal transmission in the desired mass range.

Increasing Nursing Students' Knowledge of Autism Spectrum Disorder by Using a Standardized Patient.

Nursing students participated in a simulation using a standardized patient role-playing an adolescent with autism spectrum disorder (ASD). The researchers used student feedback to develop and improve a simulation aimed at increasing learner skills and knowledge for treating ASD patients. Students indicated that the standardized patient provided realism not obtained when using static manikins or high-fidelity simulators. Students strongly agreed or agreed that classroom instruction prior to the simulation was important to increasing their knowledge of ASD. Overall, the simulation provided students an opportunity to practice and develop their clinical skills in caring for patients with ASD.

Methods for the Comparison of Differential Item Functioning across Assessments.

An important aspect of the educational and psychological evaluation of individuals is the selection of scales with appropriate evidence of reliability and validity for inferences and uses of the scores for the population of interest. One key aspect of validity is the degree to which a scale fairly assesses the construct(s) of interest for members of different subgroups within the population. Typically, this issue is addressed statistically through assessment of differential item functioning (DIF) of individual items, or differential test functioning (DTF) of sets of items within the same measure. When selecting an assessment to use for a given application (e.g., measuring intelligence), or which form of an assessment to use for a test administration, researchers need to consider the extent to which the scales work with all members of the population. Little research has examined methods for comparing the amount or magnitude of DIF/DTF present in two or more assessments when deciding which assessment to use. The current study made use of 7 different statistics for this purpose, in the context of intelligence testing. Results demonstrate that by using a variety of effect sizes, the researcher can gain insights into not only which scales may contain the least amount of DTF, but also how they differ with regard to the way in which the DTF manifests itself.

A phase-I trial of pre-operative, margin intensive, stereotactic body radiation therapy for pancreatic cancer: the 'SPARC' trial protocol.

BACKGROUND: Standard therapy for borderline-resectable pancreatic cancer in the UK is surgery with adjuvant chemotherapy, but rates of resection with clear margins are unsatisfactory and overall survival remains poor. Meta-analysis of single-arm studies shows the potential of neo-adjuvant chemo-radiotherapy but the relative radio-resistance of pancreatic cancer means the efficacy of conventional dose schedules is limited. Stereotactic radiotherapy achieves sufficient accuracy and precision to enable pre-operative margin-intensive dose escalation with the goal of increasing rates of clear resection margins and local disease control. METHODS/DESIGN: SPARC is a "rolling-six" design single-arm study to establish the maximum tolerated dose for margin-intensive stereotactic radiotherapy before resection of pancreatic cancer at high risk of positive resection margins. Eligible patients will have histologically or cytologically proven pancreatic cancer defined as borderline-resectable per National Comprehensive Cancer Network criteria or operable tumour in contact with vessels increasing the risk of positive margin. Up to 24 patients will be recruited from up to 5 treating centres and a 'rolling-six' design is utilised to minimise delays and facilitate ongoing recruitment during dose-escalation. Radiotherapy will be delivered in 5 daily fractions and surgery, if appropriate, will take place 5-6 weeks after radiotherapy. The margin-intense radiotherapy concept includes a systematic method to define the target volume for a simultaneous integrated boost in the region of tumour-vessel infiltration, and up to 4 radiotherapy dose levels will be investigated. Maximum tolerated dose is defined as the highest dose at which no more than 1 of 6 patients or 0 of 3 patients experience a dose limiting toxicity. Secondary endpoints include resection rate, resection margin status, response rate, overall survival and progression free survival at 12 and 24 months. Translational work will involve exploratory analyses of the cytological and humoral immunological responses to stereotactic radiotherapy in pancreatic cancer. Radiotherapy quality assurance of target definition and radiotherapy planning is enforced with pre-trial test cases and on-trial review. Recruitment began in April 2015. DISCUSSION: This prospective multi-centre study aims to establish the maximum tolerated dose of pre-operative margin-intensified stereotactic radiotherapy in pancreatic cancer at high risk of positive resection margins with a view to subsequent definitive comparison with other neoadjuvant treatment options. TRIAL REGISTRATION: ISRCTN14138956 . Funded by CRUK.

Comorbidities in lung cancer: prevalence, severity and links with socioeconomic status and treatment.

BACKGROUND: Survival from lung cancer remains poor in Scotland, UK. Although the presence of comorbidities is known to influence outcomes, detailed quantification of comorbidities is not available in routinely collected audit or cancer registry data. The aim of the present study was to assess the prevalence and severity of comorbidities in patients with newly diagnosed lung cancer across four centres throughout Scotland using validated criteria. METHODS: Between 2005 and 2008, all patients with newly diagnosed lung cancer coming through the multidisciplinary teams in four Scottish centres were included in the study. Patient demographics, WHO/Eastern Cooperative Oncology Group performance status, clinicopathological features and primary treatment modality were recorded. RESULTS: Details of 882 patients were collected prospectively. The majority of patients (87.3%) had at least one comorbidity, the most common being weight loss (53%), chronic obstructive pulmonary disease (43%), renal impairment (28%) and ischaemic heart disease (27%). A composite score was produced that included both number and severity of comorbidities. One in seven patients (15.3%) had severe comorbidity scores. There were statistically significant variations in comorbidity scores between treatment centres and between non-small cell lung carcinoma treatment groups. Disease stage was not associated with comorbidity score. CONCLUSIONS: There is a high prevalence of multiple, severe comorbidities in Scottish patients with lung cancer, and these vary by site and treatment group. Further research is needed to determine the relationship between comorbidity scores and survival in these patients.

Active Bystander Training: Using Standardized Patient Methodology to Teach Residents to Navigate Microaggressions in Patient Encounters.

Introduction: Studies show that physicians and medical trainees who identify as underrepresented in medicine or as women experience higher rates of microaggressions during patient encounters. We designed, implemented, and evaluated an active bystander training workshop focused on mitigating microaggressions using standardized patient (SP) methodology. Methods: Internal medicine faculty members and chief residents led the workshop. Participants included 31 PGY 1 categorical and preliminary internal medicine residents. They participated in three case simulations with SPs involving microaggressions from patients toward a member of the health care team. Prior to the case simulations, a brief presentation outlined examples of microaggressions and reviewed the behavioral response framework WAKE (work with who you are, ask questions/make direct statements, involve key people, and employ distraction techniques). After each encounter, residents debriefed with an internal medicine faculty member and discussed questions related to each scenario. Results: All 31 residents participated in the workshop and, before and after the activity, completed a survey that asked them to rank their agreement with statements via a Likert scale. Participants reported statistically significant improvement in recognizing microaggressions (12% reported increase, p = .002), the ability to respond to patients who exhibit microaggressions (23% reported increase, p < .001), and the ability to debrief with team members (20% reported increase, p < .001). Discussion: SP simulations can be an effective teaching modality for microaggression response strategies during patient encounters. Additional studies are needed to further characterize the workshop's effect on other medical workforce trainees and retention of skills over time.

Modulatory ATP binding affinity in intermediate states of E2P dephosphorylation of sarcoplasmic reticulum Ca2+-ATPase.

The mechanism of ATP modulation of E2P dephosphorylation of sarcoplasmic reticulum Ca(2+)-ATPase wild type and mutant forms was examined in nucleotide binding studies of states analogous to the various intermediates of the dephosphorylation reaction, obtained by binding of metal fluorides, vanadate, or thapsigargin. Wild type Ca(2+)-ATPase displays an ATP affinity of 4 µM for the E2P ground state analog, 1 µM for the E2P transition state and product state analogs, and 11 µM for the E2 dephosphoenzyme. Hence, ATP binding stabilizes the transition and product states relative to the ground state, thereby explaining the accelerating effect of ATP on dephosphorylation. Replacement of Phe(487) (N-domain) with serine, Arg(560) (N-domain) with leucine, or Arg(174) (A-domain) with alanine or glutamate reduces ATP affinity in all E2/E2P intermediate states. Alanine substitution of Ile(188) (A-domain) increases the ATP affinity, although ATP acceleration of dephosphorylation is disrupted, thus indicating that the critical role of Ile(188) in ATP modulation is mechanistically based rather than being associated with the binding of nucleotide. Mutants with alanine replacement of Lys(205) (A-domain) or Glu(439) (N-domain) exhibit an anomalous inhibition by ATP of E2P dephosphorylation, due to ATP binding increasing the stability of the E2P ground state relative to the transition state. The ATP affinity of Ca(2)E2P, stabilized by inserting four glycines in the A-M1 linker, is similar to that of the E2P ground state, but the Ca(2+)-free E1 state of this mutant exhibits 3 orders of magnitude reduction of ATP affinity.

Simultaneous liver metastasectomy at operation for primary colorectal or gynecologic malignancy.

BACKGROUND: Treatment of synchronous resectable colorectal liver metastases has traditionally involved a staged surgical approach. Specialized centers have demonstrated good results with simultaneous resection. We aim to report our outcomes at the University of Mississippi Medical Center (UMMC) with simultaneous liver metastasectomy at the time of operation for primary colorectal or gynecologic malignancy STUDY DESIGN: From January 2010- September 2011, 6 patients underwent simultaneous resection of liver metastases and primary colorectal or gynecologic malignancy. Operative, postoperative, and pathologic data were retrospectively reviewed. RESULTS: Four patients with colorectal primaries underwent simultaneous resection. One received abdominoperineal resection with resection of lesions in hepatic segments II and VII. A second received right hemicolectomy with en bloc resection of gallbladder and segments IV and V. The third and fourth patients both underwent left colectomy with resection of segments IV and V, respectively. All resections were non-anatomic, and frozen-sections were confirmed to be negative at the resection base. No patients suffered additional postoperative morbidity or mortality related to liver resection. Two patients had ovarian cancer with metastatic disease to the liver. The first underwent en bloc resection ofgallbladder and segments IV and V along with extensive debulking. The second had recurrent ovarian cancer with metastases with liver segments VI and VII. Both patients underwent simultaneous resection with no added postoperative morbidity or mortality attributed to hepatic resection. For gynecologic malignancy, the objective is to remove bulky disease, and although microscopic margins were positive, the goal of tumor load reduction was achieved. CONCLUSIONS: Liver resection at the time of operation for primary colorectal or gynecologic malignancy can safely be performed with the benefit of avoiding morbidity of a second laparotomy without compromising safety.

The prediction of intelligence in preschool children using alternative models to regression.

Statistical prediction of an outcome variable using multiple independent variables is a common practice in the social and behavioral sciences. For example, neuropsychologists are sometimes called upon to provide predictions of preinjury cognitive functioning for individuals who have suffered a traumatic brain injury. Typically, these predictions are made using standard multiple linear regression models with several demographic variables (e.g., gender, ethnicity, education level) as predictors. Prior research has shown conflicting evidence regarding the ability of such models to provide accurate predictions of outcome variables such as full-scale intelligence (FSIQ) test scores. The present study had two goals: (1) to demonstrate the utility of a set of alternative prediction methods that have been applied extensively in the natural sciences and business but have not been frequently explored in the social sciences and (2) to develop models that can be used to predict premorbid cognitive functioning in preschool children. Predictions of Stanford-Binet 5 FSIQ scores for preschool-aged children is used to compare the performance of a multiple regression model with several of these alternative methods. Results demonstrate that classification and regression trees provided more accurate predictions of FSIQ scores than does the more traditional regression approach. Implications of these results are discussed.

Single modality radical radiotherapy is an acceptable alternative for the older patient with squamous cell carcinoma of the oesophagus.

BACKGROUND: Oesophageal cancer remains a common cause of cancer mortality worldwide. Increasingly, oncology centres are treating an older population and comorbidities may preclude multimodality treatment with chemoradiotherapy (CRT). We review outcomes of radical radiotherapy (RT) in an older population treating squamous cell carcinoma (SCC) oesophagus. METHODS: Patients over 65 years receiving RT for SCC oesophagus between 2013 and 2016 in the West of Scotland were identified. Kaplan-Meier and Cox-regression analysis were used to compare overall survival (OS) between patients treated with radical RT and radical CRT. RESULTS: There were 83 patients over 65 years treated with either RT (n=21) or CRT (n=62). There was no significant difference in median OS between CRT versus RT (26.8 months vs 28.5 months, p=0.92). All patients receiving RT completed their treatment whereas 11% of CRT patients did not complete treatment. CONCLUSION: Survival in this non-trial older patient group managed with CRT is comparable to that reported in previous trials. RT shows better than expected outcomes which may reflect developments in RT technique. This review supports RT as an alternative in older patients, unfit for concurrent treatment.

Characterisation of 99mTc EDDA/HYNIC-TOC (Tektrotyd) physiological and neuroendocrine tumour uptake using SPECT/CT standardised uptake values: initial experience.

99mTc Ethylene diamine N,N'-diacetic acid hydrazinonicotinamide-conjugated Tyr3-octreotide (99mTc EDDA/HYNIC-TOC) single photon emission tomography/computed tomography (SPECT/CT) imaging of somatostatin receptors is used in the assessment of neuroendocrine tumours (NETs). The objective of this study was to characterise quantitative standardised uptake value (SUV) SPECT/CT of normal physiological uptake and NET disease. Forty-four patients (22 female and 22 male) referred for 99mTc EDDA/HYNIC-TOC SPECT/CT imaging for diagnosis/primary staging (n = 28) or the assessment of residual/recurrent disease (n = 16) were included. SPECT/CT SUVmax values were determined for normal physiological uptake (spleen, kidney, liver and bone) and NET disease (liver metastases, metastatic lymph nodes, bone metastases and intrapulmonary lesions). Statistical testing was performed to compare normal uptake and NET disease uptake in liver and bone (Student's t-test). The highest normal physiological uptake was observed in the spleen (mean SUVmax 29.8, SD 13.7), with lower uptake in the kidneys (16.7, 3.2) and liver (7.3, 2.1). Increased SUVmax values were observed in primary tumour and metastatic disease, greatest in liver metastases (21.8, 13.3), with lower, similar values obtained for metastatic lymph nodes (16.3, 7.5) and intrapulmonary lesions (17.5, 16.8). SUVmax in bone metastases averaged 12.9 (7.0). Significant differences were observed between normal and metastatic SUVmax in the liver and bone (P < 0.01). SPECT/CT SUV quantification is feasible in a manner similar to PET/CT. 99mTc EDDA/HYNIC-TOC SPECT/CT SUVmax has been characterised in NET disease, demonstrating high target to non-target ratios for primary tumours and metastatic lesions.

SPARC, a phase-I trial of pre-operative, margin intensified, stereotactic body radiation therapy for pancreatic cancer.

BACKGROUND AND PURPOSE: Following resection of pancreatic cancer, risk of positive margins and local recurrence remain high, especially for borderline-resectable pancreatic cancer (BRPC). We aimed to establish the maximum tolerated dose of a margin-intensified five-fraction stereotactic body radiotherapy (SBRT) regimen designed to treat the region at risk. MATERIALS AND METHODS: We conducted a prospective multicentre phase-1 rolling-six dose-escalation study. BRPC patients received pre-operative SBRT, with one dose to the primary tumour and an integrated boost to the region where tumour was in contact with vasculature. Four dose-levels were proposed, with starting dose 30 Gy to primary PTV and 45 Gy to boost volume (PTV_R), in five daily fractions. Primary endpoint was maximum tolerated dose (MTD), defined as highest dose where zero of three or one of six patients experienced dose-limiting toxicity (DLT). RESULTS: Twelve patients were registered, eleven received SBRT. Radiotherapy was well tolerated with all treatment completed as scheduled. Dose was escalated one level up from starting dose without encountering any DLT (prescribed 32.5 Gy PTV, 47.5 Gy PTV_R). Nine serious adverse reactions or events occurred (seven CTCAE Grade 3, two Grade 4). Two patients went on to have surgical resection. Median overall survival for SBRT patients was 8.1 months. The study closed early when it was unable to recruit to schedule. CONCLUSION: Toxicity of SBRT was low for the two dose-levels that were tested, but MTD was not established. Few patients subsequently underwent resection of pancreatic tumour after SBRT, and it is difficult to draw conclusions regarding the safety or toxicity of these therapies in combination.

An unusual cause of paraesthesia in a neo-adjuvant gastro-oesophageal cancer.

There is ongoing debate about the best neo-adjuvant strategy for localised resectable oesophageal cancer, however chemotherapy is often employed. Both oesophageal cancer and cisplatin carry an increased risk of thrombosis. Here, we look at an unusual finding in a previously fit woman who presented following neo-adjuvant chemotherapy for resectable oesophageal cancer with increasing difficulty in walking and lower limb paraesthesia. This case looks particularly at the diagnostic challenge and concerns raised in a patient undergoing radical treatment as well as the challenge of complications secondary to treatment with chemotherapy. Willingness to reassess and revisit is a vital part of the diagnostic process. Vascular complications of a disease can be notorious to diagnose and, as in this case can mimic arguably more logical diagnoses. Cancer care provides the unique challenge of investigating unusual presentations related both to disease and treatment.

Explicit bias among fourth-year medical students.

The aim of this study was to analyze themes related to explicit bias in patient-doctor relationships among fourth-year medical students. Class cohorts between 2013 and 2016 taking an online elective, "Self and Culture," submitted reflections about explicit bias. Thematic analysis was conducted on 283 student submissions totaling 849 entries until saturation. Themes included explicit bias toward patients with obesity, those who smoked, those from low-socioeconomic conditions, and, to a lesser extent, race/ethnicity. Themes related to the patient-doctor relationship included a negative impact on the relationship itself, trust, treatment of the patient, and patient experience. Themes related to making a positive impact included seeking positive treatment of the patient, understanding patients' circumstances rather than making assumptions, partnering with the patient, and education. Furthermore, researchers noted external versus internal attribution of the bias. Some students used neutral language to explain explicit biases, whereas fewer used internal attribution language. Results demonstrated that this type of reflection promoted personal insight, and faculty members should be trained to ensure successful crucial conversations about the impact of assumptions and biases on patient treatment, care plans, and health disparities. Finally, the curriculum should be intentional, providing experiences with marginalized populations to develop cultural humility and empathy.

The downstaging approach to irresectable oesophageal and gastric cancer: a single centre experience.

BACKGROUND: There is uncertainty over optimal management of locally advanced non-metastatic oesophageal and gastric (OG) adenocarcinomas which are deemed irresectable at time of diagnosis due to local tumour or nodal burden. Current practice in our regional centre is to administer chemotherapy in a "downstaging" strategy in the hope of achieving tumour shrinkage to allow radical treatment. Patients without sufficient response to downstaging are treated palliatively. The aim of this study was to review our single unit outcomes of this treatment strategy. METHODS: Data was collected retrospectively from electronic patient records on all cases discussed at regional MDT over a 32-month period (January 2015-August 2017). RESULTS: A total of 44 patients [70.5% male, median age 70 years, 13 (29.5%) oesophageal, 12 (27.3%) junctional and 19 (43.2%) gastric] were included in the study. Thirty-six (81.8%) of patients received the full number of planned cycles of chemotherapy; toxicity and disease progression (both 6.8% of cases) were the most common reasons for early cessation of treatment. Seventeen (38.6%) patients underwent resection and an R0 resection was achieved in 13 (76.5%) of these patients. After median follow up of 16.8 months, the median overall survival (OS) in the resection vs. palliative cohorts was 42.6 vs. 16.4 months (P<0.05). CONCLUSIONS: Our data show that a downstaging approach can be successfully implemented (R0 resection achieved) in up to a third of patients with good survival results. Further prospective data identifying patient and pathological characteristics predicting response to treatment are needed to optimise selection into a downstaging programme.

Unexpected phosphoryl transfer from Asp351 to fluorescein attached to Lys515 in sarcoplasmic reticulum Ca2+-ATPase.

Sarcoplasmic reticulum Ca(2+)-ATPase is an ion pump whose catalytic cycle includes the transient formation of an acyl phosphate at Asp(351), and fluorescein isothiocyanate is a covalent inhibitor of ATP binding to this pump, known to specifically derivatize Lys(515) in the nucleotide-binding site. It was previously found that an unusually stable, phosphorylated form of fluorescein-ATPase, with low fluorescence, is obtained following Ca (2+) loading with acetyl phosphate as energy source and then chelation with EGTA of Ca(2+) on the cytosolic side. Here we show that the phospho-linkage in this low fluorescent species is stable at alkaline pH, unlike the acyl phosphate at Asp(351). Moreover, the low fluorescence and stable phosphoryl group track together in primary and secondary tryptic subfragments, separated by SDS-PAGE after denaturation. Finally, normal fluorescence and absorbance are recovered upon treatment with alkaline phosphatase after extensive trypsinolysis. We conclude that the low fluorescent species is the result of the phosphoryl group being transferred from Asp (351) to the fluorescein moiety during pump reversal, yielding fluorescein monophosphate tethered to Ca(2+)-ATPase.