Syndecan-4 is required for early-stage repair responses during zebrafish heart regeneration

BACKGROUND

The healing process after a myocardial infarction (MI) in humans involves complex events that replace damaged tissue with a fibrotic scar. The affected cardiac tissue may lose its function permanently. In contrast, zebrafish display a remarkable capacity for scar-free heart regeneration. Previous studies have revealed that syndecan-4 (SDC4) regulates inflammatory response and fibroblast activity following cardiac injury in higher vertebrates. However, whether and how Sdc4 regulates heart regeneration in highly regenerative zebrafish remains unknown.

METHODS AND RESULTS

This study showed that sdc4 expression was differentially regulated during zebrafish heart regeneration by transcriptional analysis. Specifically, sdc4 expression increased rapidly and transiently in the early regeneration phase upon ventricular cryoinjury. Moreover, the knockdown of sdc4 led to a significant reduction in extracellular matrix protein deposition, immune cell accumulation, and cell proliferation at the lesion site. The expression of tgfb1a and col1a1a, as well as the protein expression of Fibronectin, were all down-regulated under sdc4 knockdown. In addition, we verified that sdc4 expression was required for cardiac repair in zebrafish via in vivo electrocardiogram analysis. Loss of sdc4 expression caused an apparent pathological Q wave and ST elevation, which are signs of human MI patients.

CONCLUSIONS

Our findings support that Sdc4 is required to mediate pleiotropic repair responses in the early stage of zebrafish heart regeneration.

The Finkelstein-Schoenfeld Test: A Note on Some Overlooked Issues Concerning Power

In this note, we express our viewpoint regarding power considerations, via simulation studies, in clinical study design using hierarchical composite endpoint and Finkelstein-Schoenfeld test.

A propensity score-integrated approach for leveraging external data in a randomized controlled trial with time-to-event endpoints

In a randomized controlled trial with time-to-event endpoint, some commonly used statistical tests to test for various aspects of survival differences, such as survival probability at a fixed time point, survival function up to a specific time point, and restricted mean survival time, may not be directly applicable when external data are leveraged to augment an arm (or both arms) of an RCT. In this paper, we propose a propensity score-integrated approach to extend such tests when external data are leveraged. Simulation studies are conducted to evaluate the operating characteristics of three propensity score-integrated statistical tests, and an illustrative example is given to demonstrate how these proposed procedures can be implemented.

Propensity score-incorporated adaptive design approaches when incorporating real-world data

The propensity score-integrated composite likelihood (PSCL) method is one method that can be utilized to design and analyze an application when real-world data (RWD) are leveraged to augment a prospectively designed clinical study. In the PSCL, strata are formed based on propensity scores (PS) such that similar subjects in terms of the baseline covariates from both the current study and RWD sources are placed in the same stratum, and then composite likelihood method is applied to down-weight the information from the RWD. While PSCL was originally proposed for a fixed design, it can be extended to be applied under an adaptive design framework with the purpose to either potentially claim an early success or to re-estimate the sample size. In this paper, a general strategy is proposed due to the feature of PSCL. For the possibility of claiming early success, Fisher's combination test is utilized. When the purpose is to re-estimate the sample size, the proposed procedure is based on the test proposed by Cui, Hung, and Wang. The implementation of these two procedures is demonstrated via an example.

Recovery of Copper and Zinc from Livestock Bio-Sludge with An Environmentally Friendly Organic Acid Extraction

Pig farmers in Taiwan tend to overdose copper (Cu) and zinc (Zn) in animal feeds to ensure pig health. The application of Cu- or Zn-rich livestock compost to fields can result in high Cu/Zn residues in surface soil and violate limitations for zinc and copper in land applications. This study aims to extract Cu and Zn from sludge using organic acid or H2O2/organic acids. The livestock bio-sludge was dried and treated with different concentrations of acetic acid (1N, 2N, and 4N). The acid-extracted sludge was then treated with or without adding H2O2 during different periods (4, 24, and 48 h) to investigate the efficiency of acid extraction of Cu and Zn. The supernatant of the acid-extracted product was separated from the residues through centrifugation. Experimental results showed that the treatment set of dried bio-sludge with 2% H2O2 significantly promoted the removal efficiency of Cu and Zn from the bio-sludge (p < 0.01). The best removal efficiency of Cu and Zn from the bio-sludge was 40% and 70%, respectively, using 4N acetic acid in the 48 h group. The study shows a green method for extracting Cu and Zn from livestock sludge, enhancing the sustainability of intensive livestock farming.

[A phase I study of subcutaneous envafolimab (KN035) monotherapy in Chinese patients with advanced solid tumors]

Objective: To evaluate the safety and antitumor activity of envafolimab monotherapy in Chinese patients with advanced solid tumors. Methods: This open-label, multicenter phase I trial included dose escalation and dose expansion phases. In the dose escalation phase, patients received subcutaneous 0.1, 0.3, 1.0, 2.5, 5.0 or 10.0 mg/kg envafolimab once weekly (QW) following a modified "3+ 3" design. The dose expansion phase was performed in the 2.5 mg/kg and 5.0 mg/kg (QW) dose cohorts. Results: At November 25, 2019, a total of 287 patients received envafolimab treatment. During the dose escalation phase, no dose-limiting toxicities (DLT) was observed. In all dose cohorts, drug-related treatment-emergent adverse events (TEAEs) for all grades occurred in 75.3% of patients, and grade 3 or 4 occurred in 20.6% of patients. The incidence of immune-related adverse reactions (irAE) was 24.0% for all grades, the most common irAEs (≥2%) included hypothyroidism, hyperthyroidism, immune-associated hepatitis and rash. The incidence of injection site reactions was low (3.8%), all of which were grades 1-2. Among the 216 efficacy evaluable patients, the objective response rate (ORR) and disease control rate (DCR) were 11.6% and 43.1%, respectively. Median duration of response was 49.1 weeks (95% CI: 24.0, 49.3). Pharmacokinetic (PK) exposure to envafolimab is proportional to dose and median time to maximum plasma concentration is 72-120 hours based on the PK results from the dose escalation phase of the study. Conclusion: Subcutaneous envafolimab has a favorable safety and promising preliminary anti-tumor activity in Chinese patients with advanced solid tumors.

Adjuvant Chemoradiotherapy within One Year of Resection for Molecularly Defined Astrocytoma

PURPOSE/OBJECTIVE(S)

Treatments for diffuse low-grade gliomas (LGG) are controversial. Level I evidence supports the use of adjuvant radiotherapy (RT) and PCV chemotherapy for histologic LGG, but integration of molecular biomarkers in recent WHO classification and the emergence of temozolomide chemotherapy for gliomas necessitates additional investigation of the optimal treatment and timing of postoperative interventions. We hypothesized molecularly-defined LGG (IDH-mutant astrocytoma (astro) and IDH-mutant, 1p/19q-codeleted oligodendroglioma (oligo)) may have different clinical outcomes following adjuvant RT (aRT) with chemotherapy (aRT+chemo) vs observation or chemo alone.

MATERIALS/METHODS

A retrospective analysis of consecutive adult patients diagnosed with WHO Grade 2 astrocytoma or oligodendroglioma who underwent initial resection at a single institution from January 1998 to November 2017 was performed. Wilcoxon rank sum and Chi-squared tests were used to compare continuous and categorical variables, respectively. Survival analyses were performed using the Kaplan-Meier method and Cox proportional hazards models. Patients without clinical progression or death were censored at the date of last follow-up. Pre-operative and post-operative T2 FLAIR hyperintense tumor volumes were quantified using 3D Slicer to calculate extent of resection (EOR).

RESULTS

A total of 342 patients with molecularly-defined LGG (178 astro, 164 oligo) were identified with a median follow up of 9.1 yr. 171 (50%) patients received RT during their treatment course, of which 31 (18%) were treated with aRT within 1 year of diagnosis. The median aRT dose was 54 Gy (range: 40-60 Gy). aRT was more likely for astro (58%) vs oligo (41%, p = 0.001) and for patients who had resections with lower median EOR (88% vs 95%, p = 0.014). 53 patients (15%) were treated with chemo alone, and 136 patients (40%) were treated with aRT+chemo. Temozolomide was used for 161 patients (85%). For astro, aRT+chemo was associated with longer PFS (median 14.9 yr) compared to observation (4.8 yr, p = 0.05), aRT without chemo (5.2 yr, p = 0.01), or chemo alone (4.7 yr, p = 0.02). For oligo, aRT+chemo was associated with longer PFS (median not reached) compared to aRT without chemo (1.6 yr, p = 0.03), but not when compared to observation (median not reached, p = 0.47), or chemo alone (7.9 yr, p = 0.45). Multivariate analysis showed preoperative tumor volume, EOR, and aRT+chemo (but not aRT or chemo alone) were independently associated with astro PFS compared to observation. Propensity matching based on pre-operative tumor volume, EOR, and age demonstrated longer astro PFS after aRT+chemo (14.9 yr) compared to observation or chemo alone (4.5 yr, p = 0.015), without significant difference in OS (18.2 vs. 11.5 yr, p = 0.40).

CONCLUSION

Retrospective data from a single institution support the use of adjuvant radiotherapy with chemotherapy for patients with molecular astrocytomas, while the role of this approach for oligodendrogliomas is unclear in this cohort.

[Study of immunophenotypic characteristics, clinicopathological parameters and prognosis in gastric cancer microenvironment]

Objective: To explore the immunophenotypic characteristics of gastric cancer microenvironment and analyze its correlation with clinicopathological parameters and prognosis of patients. Methods: The expression levels of leukocyte differentiation antigen (CD) 8, CD4, T lymphocyte immunoglobulin mucoprotein 3 (TIM3), human forkhead box protein P3 (Foxp3) and co-localized tumor infiltrating lymphocytes (TILs) were detected in 92 cases of gastric cancer tissue [58 males and 34 females; aged M(Q1, Q3), 70(59, 77) years ] and 84 cases of paracancer tissue [57 males and 27 females, aged 70(59, 77) years] purchased from Shanghai Xinchao Biotechnology Co., Ltd., and the samples were from 28 hospitals in the sample bank. Gastric cancer and adjacent tissues were divided into high expression group and low expression group according to the optimal cut-off value of positive lymphocytepercentage. The expression of immunophenotypes in gastric cancer and adjacent tissues was analyzed. Kaplan-Meier method was used for survival analysis. Cox proportional hazard model was used to explore the prognostic factors of gastric cancer patients. Results: The optimal cut-off values of CD8, CD4, TIM3 and Foxp3 positive cells in gastric cancer were 12.73%, 1.39%, 10.77% and 2.44%, respectively. The expression of Foxp3 in gastric cancer tissues was higher than that in paracancer tissues [M (Q1, Q3), 0.93 (0.45, 2.16) vs 0.31 (0.09, 0.86), P<0.001], and the expression of CD8 [4.92 (2.34, 8.80) vs 8.81 (6.61, 12.17), P<0.001], CD4 [4.79 (1.77, 11.36) vs 8.40 (4.84, 12.77), P=0.022] and TIM3 [5.68 (2.05, 11.58) vs 7.07 (3.13, 11.43), P=0.338] were lower than that in paracancer tissues. There were significant differences in TIM3 expression in gastric cancer patients with different lymph node metastasis and clinical stage (all P<0.05). The 5-year survival rate of patients with high CD4 expression, low TIM3 expression and low Foxp3 expression in gastric cancer tissues was poor, among which the high CD4 expression and low CD4 expression groups were 29.3% and 64.7%, respectively; The high and low TIM3 expression groups were 60.9% and 30.4%, respectively; The high and low Foxp3 expression groups were 64.3% and 33.3%, respectively (all P<0.05). The optimal cut-off values of CD8+TIM3+TILs, CD4+TIM3+TILs, CD8+Foxp3+TILs and CD4+Foxp3+TILs were 3.86%, 0.23%, 0.08% and 0.76%, respectively. Colocalization analysis showed that the expression of CD8+Foxp3+TILs in gastric cancer tissues was higher than that in adjacent tissues(all P<0.05). Multivariate Cox regression analysis showed that high expression of CD4 (HR=3.079, 95%CI: 1.350-7.024,P=0.008), low expression of TIM3 (HR=0.428, 95%CI: 0.208-0.879, P=0.021) and low expression of Foxp3 (HR=0.288, 95%CI: 0.121-0.687, P=0.005) were the influencing factor for the 5-year survival rate of patients with gastric cancer after operation. Conclusions: Gastric cancer tissues have complex immune microenvironment characteristics. The expression of CD4, TIM3 and Foxp3 is closely related to the prognosis of patients.

[Diagnostic value of nasal nitric oxide for children with primary ciliary dyskinesia]

Objective: To evaluate the value of nasal nitric oxide (nNO) measurement as a diagnostic tool for Chinese patients with primary ciliary dyskinesia (PCD). Methods: This study is a retrospective study. The patients were recruited from those who were admitted to the respiratory Department of Respiratory Medicine, Children's Hospital of Fudan University from March 2018 to September 2022. Children with PCD were included as the PCD group, and children with situs inversus or ambiguus, cystic fibrosis (CF), bronchiectasis, chronic suppurative lung disease and asthma were included as the PCD symptom-similar group. Children who visited the Department of Child health Care and urology in the same hospital from December 2022 to January 2023 were selected as nNO normal control group. nNO was measured during plateau exhalation against resistance in three groups. Mann-Whitney U test was used to analyze the nNO data. The receiver operating characteristic of nNO value for the diagnosis of PCD was plotted and, the area under the curve and Youden index was calculated to find the best cut-off value. Results: nNO was measured in 40 patients with PCD group, 75 PCD symptom-similar group (including 23 cases of situs inversus or ambiguus, 8 cases of CF, 26 cases of bronchiectasis or chronic suppurative lung disease, 18 cases of asthma), and 55 nNO normal controls group. The age of the three groups was respectively 9.7 (6.7,13.4), 9.3 (7.0,13.0) and 9.9 (7.3,13.0) years old. nNO values were significantly lower in children with PCD than in PCD symptom-similar group and nNO normal controls (12 (9,19) vs. 182 (121,222), 209 (165,261) nl/min, U=143.00, 2.00, both P<0.001). In the PCD symptom-similar group, situs inversus or ambiguus, CF, bronchiectasis or chronic suppurative lung disease and asthma were significantly higher than children with PCD (185 (123,218), 97 (52, 132), 154 (31, 202), 266 (202,414) vs. 12 (9,19) nl/min,U=1.00, 9.00, 133.00, 0, all P<0.001). A cut-off value of 84 nl/min could provide the best sensitivity (0.98) and specificity (0.92) with an area under the curve of 0.97 (95%CI 0.95-1.00, P<0.001). Conclusions: nNO value can draw a distinction between patients with PCD and others. A cut-off value of 84 nl/min is recommended for children with PCD.

[Research progress of metal micro-battery dressings in wound repair]

To develop the dressings that can both inhibit bacterial infection and actively promote healing is of great importance for wound repair and the development of medical technology. Electrical stimulation has multiple roles in wound healing, including hemostasis, antibacterial, anti-inflammatory, guidance of cell migration, promotion of re-epithelialization, and proliferation of cells. Metal micro-battery can provide a stable source of electrical stimulation energy without an external power source. Thus, the integration of metal micro-battery with medical dressings opens up new opportunities for the wireless application of electrical stimulation in wound repair. In this review, the mechanism of the effect of electrical stimulation on wound healing is systematically presented, then recent advances in metal micro-battery dressings, including preparation methods, antibacterial performance, and healing properties are mainly introduced, and the current challenges and prospects of metal micro-battery dressings are also provided.

Principled leveraging of external data in the evaluation of diagnostic devices via the propensity score-integrated composite likelihood approach

In the area of diagnostics, it is common practice to leverage external data to augment a traditional study of diagnostic accuracy consisting of prospectively enrolled subjects to potentially reduce the time and/or cost needed for the performance evaluation of an investigational diagnostic device. However, the statistical methods currently being used for such leveraging may not clearly separate study design and outcome data analysis, and they may not adequately address possible bias due to differences in clinically relevant characteristics between the subjects constituting the traditional study and those constituting the external data. This paper is intended to draw attention in the field of diagnostics to the recently developed propensity score-integrated composite likelihood approach, which originally focused on therapeutic medical products. This approach applies the outcome-free principle to separate study design and outcome data analysis and can mitigate bias due to imbalance in covariates, thereby increasing the interpretability of study results. While this approach was conceived as a statistical tool for the design and analysis of clinical studies for therapeutic medical products, here, we will show how it can also be applied to the evaluation of sensitivity and specificity of an investigational diagnostic device leveraging external data. We consider two common scenarios for the design of a traditional diagnostic device study consisting of prospectively enrolled subjects, which is to be augmented by external data. The reader will be taken through the process of implementing this approach step-by-step following the outcome-free principle that preserves study integrity.

Development and internal validation of the survival time risk score in patients treated for oesophageal cancer with palliative intent in South Africa

BACKGROUND

Most patients who present to South African state hospitals with advanced stage oesophageal squamous cell cancer (OSCC) disease receive palliative treatment. This study aimed to assess the factors that influence survival in patients with OSCC who received palliative management and to develop a prognostic score to aid clinicians in decisionmaking.

METHODS

Analysis of a prospectively collected database assessed factors influencing survival of patients diagnosed with OSCC receiving palliative treatment. Factors assessed included patient demographics, clinical and laboratory data and tumour factors. A multivariable logistic regression model was used to assess for significant factors associated with survival time and a prognostic score was developed and internally validated based on these factors.

RESULTS

There were 384 patients with a male-to-female ratio of 1.3:1. The median survival of the cohort was 3.7 months. Factors that influenced survival on multivariate analysis included area of residence (aOR 1.82, 95% CI 1.02-3.24), performance status (aOR 2.56, 95% CI 1.50-4.35), body mass index (aOR 1.87, 95% CI 1.14-3.06) and serum albumin (aOR 3.06, 95% CI 1.46-6.42). The final prognostic score contained three of the four independent variables based on the regression coefficient for each variable. After internal validation, the risk score maintained fair discrimination and good calibration.

CONCLUSION

The prognostic scoring system based on patient performance status, body mass index and serum albumin, if validated on an independent cohort, would allow more objective decisions on whether to stage or not prior to embarking on palliative treatment, streamlining care and improving quality of life.

Synthesis of Optically Active Organofluorides by Ring Opening of Oxazolidinone-Fused Aziridines

A general method for synthesizing optically active, primary, secondary, and tertiary organofluorides was developed. This chiral pool synthesis utilized the skeleton of arabinose to generate diastereomerically pure 2-oxazolidinone-fused aziridines, which underwent ring opening with a fluoride anion. The adducts, polyoxygenated organofluorides, were useful precursors to various fluorinated compounds, such as fluorinated amino acids.

Propensity score-integrated approach to survival analysis: leveraging external evidence in single-arm studies

External data, referred to as data external to the traditional clinical study being planned, include but are not limited to real-world data (RWD) and data collected from clinical studies being conducted in the past or in other countries. The external data are sometimes leveraged to augment a single-arm, prospectively designed study when appropriate. In such an application, recently developed propensity score-integrated approaches including PSPP and PSCL can be used for study design and data analysis when the clinical outcomes are binary or continuous. In this paper, the propensity score-integrated Kaplan-Meier (PSKM) method is proposed for a similar situation but the outcome of interest is time-to-event. The propensity score methodology is used to select external subjects that are similar to those in the current study in terms of baseline covariates and to stratify the selected subjects from both data sources into more homogeneous strata. The stratum-specific PSKM estimators are obtained based on all subjects in the stratum with the external data being down-weighted, and then these estimators are combined to obtain an overall PSKM estimator. A simulation study is conducted to assess the performance of the PSKM method, and an illustrative example is presented to demonstrate how to implement the proposed method.

New n-p Junction Floating Gate to Enhance the Operation Performance of a Semiconductor Memory Device

To lower the charge leakage of a floating gate device and improve the operation performance of memory devices toward a smaller structure size and a higher component capability, two new types of floating gates composed of pn-type polysilicon or np-type polysilicon were developed in this study. Their microstructure and elemental compositions were investigated, and the sheet resistance, threshold voltages and erasing voltages were measured. The experimental results and charge simulation indicated that, by forming an n-p junction in the floating gate, the sheet resistance was increased, and the charge leakage was reduced because of the formation of a carrier depletion zone at the junction interface serving as an intrinsic potential barrier. Additionally, the threshold voltage and erasing voltage of the np-type floating gate were elevated, suggesting that the performance of the floating gate in the operation of memory devices can be effectively improved without the application of new materials or changes to the physical structure.

Sudden quadriparesis after non-overdose local anesthesia

Background

A well-known anesthetic, lidocaine is the most widely used local anesthetic. Local anesthetic systemic toxicity (LAST) is a life-threatening event with common and prominent presentations of central nervous system (CNS) toxicity and cardiovascular toxicity. The most frequent and prominent early warning signs and symptoms of LAST are central nervous system symptoms. While rare, cases quadriparesis after the administration of lidocaine has been reported.

Case presentation

In this paper, we report a very rare case of quadriparesis after local anesthesia administration for vocal cord cyst-removal surgery, which dramatically improved after treatment. LAST can occur during various routes of lidocaine administration, such as local spray. A possible mechanism of our case could be the local diffusion of lidocaine to the spinal cord, which caused the symptoms to mimic anterior cord syndrome.

Conclusions

Our case presented a favorable outcome following the administration of intravenous lipid emulsion (ILE) for non-over dose local anesthetic drug induced spinal cord inhibition symptoms. These findings highlight the need for further research on the use of ILE to reverse LAST and other adverse effects of local anesthetics.

Exposure to polystyrene microplastics impairs hippocampus-dependent learning and memory in mice

Microplastics (MPs) pollution has become a serious environmental issue worldwide, but its potential effects on health remain unknown. The administration of polystyrene MPs (PS-MPs) to mice for eight weeks impaired learning and memory behavior. PS-MPs were detected in the brain especially in the hippocampus of these mice. Concurrently, the hippocampus had decreased levels of immediate-early genes, aberrantly enhanced synaptic glutamate AMPA receptors, and elevated neuroinflammation, all of which are critical for synaptic plasticity and memory. Interestingly, ablation of the vagus nerve, a modulator of the gut-brain axis, improved the memory function of PS-MPs mice. These results indicate that exposure to PS-MPs in mice alters the expression of neuronal activity-dependent genes and synaptic proteins, and increases neuroinflammation in the hippocampus, subsequently causing behavioral changes through the vagus nerve-dependent pathway. Our findings shed light on the adverse impacts of PS-MPs on the brain and hippocampal learning and memory.

Leveraging real-world evidence for determining performance goals for medical device studies

Performance goals are numerical target values pertaining to effectiveness or safety endpoints in single-arm medical device clinical studies. Typically, performance goals are determined at the planning stage of the investigational study under consideration based on summarized outcome information from existing relevant clinical trials. In recent years, there is a growing interest in leveraging real-world evidence in medical product development. In this article, we introduce a new method for proposing performance goals by leveraging real-world evidence. The method applies entropy balancing to address possible patient dissimilarities between the study's target patient population and existing real-world patients, and can take into account operation differences between clinical studies and real-world clinical practice. An illustrative example is provided to demonstrate how to implement the proposed method for performance goal determination while leveraging real-world evidence.

Propensity score-integrated power prior approach for augmenting the control arm of a randomized controlled trial by incorporating multiple external data sources

In this paper, a propensity score-integrated power prior approach is developed to augment the control arm of a two-arm randomized controlled trial (RCT) with subjects from multiple external data sources such as real-world data (RWD) and historical clinical studies containing subject-level outcomes and covariates. The propensity scores for the subjects in the external data sources versus the subjects in the RCT are first estimated, and then subjects are placed in different strata based on their estimated propensity scores. Within each propensity score stratum, a power prior is formulated with the information contributed by the external data sources, and Bayesian inference on the treatment effect is obtained. The proposed approach is implemented under the two-stage study design framework utilizing the outcome-free principle to ensure the integrity of a study. An illustrative example is provided to demonstrate the implementation of the proposed approach.

Topological hybrid semimetal phases and anomalous Hall effects in a three dimensional magnetic topological insulator

In this work, we propose a ferromagnetic Bi₂Se₃as a candidate to hold the coexistence of Weyl- and nodal-line semimetal phases, which breaks the time reversal symmetry. We demonstrate that the type-I Weyl semimetal phase, type-I-, type-II- and their hybrid nodal-line semimetal phases can arise by tuning the Zeeman exchange field strength and the Fermi velocity. Their topological responses under U(1) gauge field are also discussed. Our results raise a new way for realizing Weyl and nodal-line semimetals and will be helpful in understanding the topological transport phenomena in three-dimensional material systems.

The Drude-Smith Equation and Related Equations for the Frequency-Dependent Electrical Conductivity of Materials: Insight from a Memory Function Formalism

The Drude‐Smith equation is widely used for treating the frequency‐dependent electrical conductivity of materials in the terahertz region. An attractive feature is its sparsity of adjustable parameters. A significant improvement over Drude theory for these materials, the theory includes backscattering of the charge carriers. It has nevertheless been criticized, including by Smith himself, because of the arbitrariness of a step in the derivation. We recall a somewhat similar behavior of back scattering in fluids observed in molecular dynamics computations and discussed in terms of memory functions. We show how theories such as Drude‐Smith and Cocker et al. are examples of a broader class of theories by showing how they also arise as particular cases of a memory function formalism that divides the interactions into short and long range.

The Drude-Smith Equation and Related Equations for the Frequency-Dependent Electrical Conductivity of Materials: Insight from a Memory Function Formalism

The front cover artwork is provided by Wei-Chen Chen and Rudolph A. Marcus. The image shows an electron undergoing backscattering in a disordered solid, a phenomenon commonly described using the Drude-Smith equation represented by the damping curve. Read the full text of the Article at 10.1002/cphc.202100299.

Augmenting Both Arms of a Randomized Controlled Trial Using External Data: An Application of the Propensity Score-Integrated Approaches

Leveraging external data is a topic that have recently received much attention. The propensity score-integrated approaches are a methodological innovation for this purpose. In this paper we adapt these approaches, originally introduced to augment single-arm studies with external data, for the augmentation of both arms of a randomized controlled trial (RCT) with external data. After recapitulating the basic ideas, we provide a step-by-step tutorial of how to implement the propensity score-integrated approaches, from study design to outcome analysis, in the RCT setting in such a way that the study integrity and objectively are maintained. Both the Bayesian (power prior) approach and the frequentist (composite likelihood) approach are included. Some extensions and variations of these approaches are also outlined at the end of this paper.