Misuse of Statistical Methods in 10 Leading Chinese Medical Journals in 1998 and 2008

Statistical methods are vital to biomedical research. Our aim was to find out whether progress has been made in the last decade in the use of statistical methods in Chinese medical research. We reviewed 10 leading Chinese medical journals published in 1998 and in 2008. Regarding statistical methods, using a multiple t-test for multiple group comparison was the most common error in the t-test in both years, which significantly decreased in 2008. In contingency tables, no significant level adjustment for multiple comparison significantly decreased in 2008. In ANOVA, over a quarter of articles misused the method of multiple pair-wise comparison in both years, and no significant difference was seen between the two years. In the rank transformation nonparametric test, the error of using multiple pair-wise comparison for multiple group comparison became less common. Many mistakes were found in the randomised controlled trial (56.3% in 1998; 67.9% in 2008), non- randomised clinical trial (57.3%; 58.6%), basic science study (72.9%; 65.5%), case study or case series study (48.4%; 47.2%), and cross-sectional study (57.1%; 44.2%). Progress has been made in the use of statistical methods in Chinese medical journals, but much is yet to be done

Survival outcomes of stage I colorectal cancer:development and validation of the ACEPLY model using two prospective cohorts

BACKGROUND: Approximately 10% of stage I colorectal cancer (CRC) patients experience unfavorable clinical outcomes after surgery. However, little is known about the subset of stage I patients who are predisposed to high risk of recurrence or death. Previous evidence was limited by small sample sizes and lack of validation. METHODS: We aimed to identify early indicators and develop a risk stratification model to inform prognosis of stage I patients by employing two large prospective cohorts. Prognostic factors for stage II tumors, including T stage, number of nodes examined, preoperative carcinoma embryonic antigen (CEA), lymphovascular invasion, perineural invasion (PNI), and tumor grade were investigated in the discovery cohort, and significant findings were further validated in the other cohort. We adopted disease-free survival (DFS) as the primary outcome for maximum statistical power and recurrence rate and overall survival (OS) as secondary outcomes. Hazard ratios (HRs) were estimated from Cox proportional hazard models, which were subsequently utilized to develop a multivariable model to predict DFS. Predictive performance was assessed in relation to discrimination, calibration and net benefit. RESULTS: A total of 728 and 413 patients were included for discovery and validation. Overall, 6.7% and 4.1% of the patients developed recurrences during follow-up. We identified consistent significant effects of PNI and higher preoperative CEA on inferior DFS in both the discovery (PNI: HR = 4.26, 95% CI: 1.70–10.67, p = 0.002; CEA: HR = 1.46, 95% CI: 1.13–1.87, p = 0.003) and the validation analysis (PNI: HR = 3.31, 95% CI: 1.01–10.89, p = 0.049; CEA: HR = 1.58, 95% CI: 1.10–2.28, p = 0.014). They were also significantly associated with recurrence rate. Age at diagnosis was a prominent determinant of OS. A prediction model on DFS using Age at diagnosis, CEA, PNI, and number of LYmph nodes examined (ACEPLY) showed significant discriminative performance (C-index: 0.69, 95% CI:0.60–0.77) in the external validation cohort. Decision curve analysis demonstrated added clinical benefit of applying the model for risk stratification. CONCLUSIONS: PNI and preoperative CEA are useful indicators for inferior survival outcomes of stage I CRC. Identification of stage I patients at high risk of recurrence is feasible using the ACEPLY model, although the predictive performance is yet to be improved. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12916-022-02693-7

Exosomes Derived From Pericytes Improve Microcirculation and Protect Blood–Spinal Cord Barrier After Spinal Cord Injury in Mice

Spinal cord injury (SCI) often leads to severe and permanent paralysis and places a heavy burden on individuals, families, and society. Until now, the therapy of SCI is still a big challenge for the researchers. Transplantation of mesenchymal stem cells (MSCs) is a hot spot for the treatment of SCI, but many problems and risks have not been resolved. Some studies have reported that the therapeutic effect of MSCs on SCI is related to the paracrine secretion of cells. The exosomes secreted by MSCs have therapeutic potential for many diseases. There are abundant pericytes which possess the characteristics of stem cells in the neurovascular unit. Due to the close relationship between pericytes and endothelial cells, the exosomes of pericytes can be taken up by endothelial cells more easily. There are fewer studies about the therapeutic potential of the exosomes derived from pericytes on SCI now. In this study, exosomes of pericytes were transplanted into the mice with SCI to study the restoration of motor function and explore the underlying mechanism. We found that the exosomes derived from pericytes could reduce pathological changes, improve the motor function, the blood flow and oxygen deficiency after SCI. In addition, the exosomes could improve the endothelial ability to regulate blood flow, protect the blood-spinal cord barrier, reduce edema, decrease the expression of HIF-1α, Bax, Aquaporin-4, and MMP2, increase the expression of Claudin-5, bcl-2 and inhibit apoptosis. The experiments in vitro proved that exosomes derived from pericytes could protect the barrier of spinal cord microvascular endothelial cells under hypoxia condition, which was related to PTEN/AKT pathway. In summary, our study showed that exosomes of pericytes had therapeutic prospects for SCI

Comparison of the Volatile Components in Chinese Traditional Xiaoqu Liquor

Volatile components in Sichuan Xiaoqu liquor of Chongqing Jiangjin District, Chongqing Yongchuan District, Sichuan Kaijiang County, Sichuan Zigong were studied by the method of combining headspace solid-phase microextraction (HS-SPME) with gas chromatography coupled with mass spectrometry (GC-MS). Results showed that 29, 31, 44, 45 kinds of aromatic components were identified from the Xiaoqu liquor of Jiangjin, Chongqing Yongchuan, Kaijiang and Zigong respectively. Esters, alcohols as well as aldehydes and ketones are the main substances. According to peak area relative percentage contents, content of ethyl acetate, isoamyl alcohol and ethyl caprate in the 4 kinds of Xiaoqu liquor is relatively high

A Retrospective Survey of Research Design and Statistical Analyses in Selected Chinese Medical Journals in 1998 and 2008

BACKGROUND: High quality clinical research not only requires advanced professional knowledge, but also needs sound study design and correct statistical analyses. The number of clinical research articles published in Chinese medical journals has increased immensely in the past decade, but study design quality and statistical analyses have remained suboptimal. The aim of this investigation was to gather evidence on the quality of study design and statistical analyses in clinical researches conducted in China for the first decade of the new millennium. METHODOLOGY/PRINCIPAL FINDINGS: Ten (10) leading Chinese medical journals were selected and all original articles published in 1998 (N = 1,335) and 2008 (N = 1,578) were thoroughly categorized and reviewed. A well-defined and validated checklist on study design, statistical analyses, results presentation, and interpretation was used for review and evaluation. Main outcomes were the frequencies of different types of study design, error/defect proportion in design and statistical analyses, and implementation of CONSORT in randomized clinical trials. From 1998 to 2008: The error/defect proportion in statistical analyses decreased significantly ( = 12.03, p<0.001), 59.8% (545/1,335) in 1998 compared to 52.2% (664/1,578) in 2008. The overall error/defect proportion of study design also decreased ( = 21.22, p<0.001), 50.9% (680/1,335) compared to 42.40% (669/1,578). In 2008, design with randomized clinical trials remained low in single digit (3.8%, 60/1,578) with two-third showed poor results reporting (defects in 44 papers, 73.3%). Nearly half of the published studies were retrospective in nature, 49.3% (658/1,335) in 1998 compared to 48.2% (761/1,578) in 2008. Decreases in defect proportions were observed in both results presentation ( = 93.26, p<0.001), 92.7% (945/1,019) compared to 78.2% (1023/1,309) and interpretation ( = 27.26, p<0.001), 9.7% (99/1,019) compared to 4.3% (56/1,309), some serious ones persisted. CONCLUSIONS/SIGNIFICANCE: Chinese medical research seems to have made significant progress regarding statistical analyses, but there remains ample room for improvement regarding study designs. Retrospective clinical studies are the most often used design, whereas randomized clinical trials are rare and often show methodological weaknesses. Urgent implementation of the CONSORT statement is imperative

Using time delay in the nonlinear oscillations of magnetic levitation for simultaneous energy harvesting and vibration suppression

In this paper, the nonlinear oscillations of magnetic levitation in the presence of a time delay is investigated, with the purpose of simultaneous energy harvesting and vibration suppression. To harvest energy, a coil with seven layers of 36 gauge wire wound around the outer casing is utilized. Although the proposed control feedback consumes some power, the results show the harvestable power can be much larger than the consumed power, which makes the proposed concept feasible. The first-order perturbation method is utilized to examine the possibility of energy harvesting and vibration suppression for different selections of the delay parameters, the distances between the magnets and the external load resistances. In addition, the stability map of the time-delayed control is analytically determined. The influence of the time delay parameters chosen from Single Periodic Solutions (SPS) and Multiple Periodic Solutions (MPS) on the vibration and power amplitudes is studied. It is shown that a point chosen from the MPS region enables the system to harvest power over a broad range of excitation frequencies. Also, the effect of the distance between the magnets on the frequency response of the system is examined. In addition, to select the optimum value for the distance between the magnets for different values of the time delay parameters, a parameter called the Perfection Rate (PR), which reflects both the electrical and mechanical behavior of the system, is used. Finally, it is shown that the presence of the time delay and a point chosen from the MPS region enables the system to harvest more power over a broad range of excitation frequency and to suppress higher levels of vibration, than for a point chosen from the SPS region and without time delay

Assessment of Energy-Saving Practices of the Hospitality Industry in Macau

Macau is building a world tourism and leisure center. In the context of flourishing hospitality development, energy issues have attracted more and more attention in recent years. On the basis of the field survey of 28 hotels, an evaluation index system is built to assess the status of energy-saving and environmental protection practices in the hospitality industry in Macau. This system is built by selecting some credits from Leadership in Energy and Environmental Design (LEED) and adding several new indices according to the social and economic characteristics of Macau. The results show that the hotels have made significant efforts to improve the energy efficiency in recent years. A total of 71.4% of the hotels have formulated and implemented the energy-saving and environmental protection programs. However, there is an apparent gap in energy and environmental performance between different star-level hotels. The higher is the star-level of a hotel, the higher enthusiasm on energy-saving a hotel has, e.g., 63.6% of the 5-star hotels carried out the carbon auditing and energy management measures, but there is no 2-star hotel that adopted them. The energy-saving performance can be great improved if more efforts are made in the future, especially for the 2-star hotels. Finally, we put forward some suggestions for how to bridge this gap and present a possible roadmap for the further improvement of energy efficiency of the hotel industry in Macau. The results from this work are useful to help the government and hotel managers to take actions for improving the energy utilization and efficiency of the hospitality industry in Macau

Presyncodon, a Web Server for Gene Design with the Evolutionary Information of the Expression Hosts

In the natural host, most of the synonymous codons of a gene have been evolutionarily selected and related to protein expression and function. However, for the design of a new gene, most of the existing codon optimization tools select the high-frequency-usage codons and neglect the contribution of the low-frequency-usage codons (rare codons) to the expression of the target gene in the host. In this study, we developed the method Presyncodon, available in a web version, to predict the gene code from a protein sequence, using built-in evolutionary information on a specific expression host. The synonymous codon-usage pattern of a peptide was studied from three genomic datasets (Escherichia coli, Bacillus subtilis, and Saccharomyces cerevisiae). Machine-learning models were constructed to predict a selection of synonymous codons (low- or high-frequency-usage codon) in a gene. This method could be easily and efficiently used to design new genes from protein sequences for optimal expression in three expression hosts (E. coli, B. subtilis, and S. cerevisiae). Presyncodon is free to academic and noncommercial users; accessible at http://www.mobioinfor.cn/presyncodon_www/index.html

Analysis of the Influence Mechanism of Consumers’ Trading Behavior on Reusable Mobile Phones

The aim of this study is to investigate the decision-making mechanism of reusable mobile phone trading behaviors by using the extended theory of planned behavior. In this study, based on the survey data of 964 residents in Beijing, China and structural equation modeling method, the main factors that affect consumers&rsquo; reusable mobile phone trading behavior and their degree of influence were analyzed, followed by discussion on decision-making mechanisms. The findings show that consumers&rsquo; behavioral selection has been significantly related to four intrinsic subjective factors and fifteen external objective factors, and the combined effect of the latter ones is nearly triple of that of the former ones. Moreover, the observed variables of environmental awareness, information leakage sensitivity, trading convenience and consumer trading returns are the four most significant factors. The impact of active trading behavior is not significant. However, this may be because that there were no great trading rewards, lack of trading awareness and regulations. Finally, the study put forward relevant policy recommendations for improving the comprehensive management of recycling reusable mobile phones, and provides a theoretical reference for improving the recycling rate of reusable mobile phones