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Abstract Background Effective teaching methods are needed to improve students’ abilities in hand-eye coordination and understanding of cardiac anatomy in echocardiography education. Simulation devices have emerged as innovative teaching tools and exhibited distinctive advantages due to their ability to provide vivid and visual learning experiences. This study aimed to investigate the effect of simulation of sectional human anatomy using ultrasound on students’ learning outcomes and satisfaction in echocardiography education. Methods The study included 18 first-year clinical medical students with no prior echocardiography training. After randomization, they underwent a pre-test to assess basic knowledge. Following this, the students were divided into two groups: traditional teaching (traditional group) and simulation of sectional human anatomy using ultrasound (digital group). Each group received 60 min of instruction. Post-tests were assigned to students at two different time points: immediately after the lecture, and one week later (referred to as post-tests 1, and 2). In addition, anonymous questionnaires were distributed to students after class to investigate their satisfaction with teaching. Results Both groups showed significant improvement in their scores on post-test 1 compared to pre-test (traditional group: from 33.1 ± 8.8 to 48.1 ± 13.1, P = 0.034 vs. digital group: from 35.0 ± 6.7 to 58.0 ± 13.2, P = 0.008). However, there were no significant differences between the two groups in several post-test comparisons. Student satisfaction ratings revealed that the digital group experienced significantly greater satisfaction in areas such as subject interest, teaching style, course alignment, and interaction compared to the traditional group. Additionally, 80% of the digital group strongly endorsed the use of simulation of sectional human anatomy using ultrasound for echocardiography teaching, highlighting its effectiveness. Conclusions Simulation of sectional human anatomy using ultrasound may improve students’ understanding of echocardiography and satisfaction with the course. Our study provides evidence supporting the use of simulation teaching devices in medical education. Further research is needed to explore the long-term impact of this teaching method on students’ learning outcomes and its integration into the medical curriculum. Trial registration http://www.chictr.org.cn (registration number: ChiCTR2300074015, 27/07/2023).

Background: Immune checkpoint inhibitors (ICIs), either as monotherapy or in combination with chemotherapy, have improved the therapeutic outcome for non-small cell lung cancer (NSCLC). However, the efficacy of combination therapies, such as programmed cell death 1(PD-1)/its ligand (PD-L1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) inhibitors, in targeting different pathways remains unclear. We performed a meta-analysis to determine whether the addition of a CTLA-4 inhibitor to PD-1/PD-L1 therapy improves the efficacy of PD-1/PD-L1 monotherapy in NSCLC.Methods: We systematically searched various electronic databases for suitable trials. Only randomized controlled trials (RCTs) comparing the clinical efficacy of PD-1/PD-L1 with and without CTLA-4 were included in the analyses. The meta-analysis software RevMan 5.3 was used for statistical analyses.Results: A total of seven RCTs were retrieved. The results suggested that the combination of CTLA-4 and PD-1/PDL-1 inhibitors did not show enhanced efficacy over PD1/PDL-1 inhibitor monotherapy as determined by overall survival (OS) (HR = 0.98, 95% CI = 0.84–1.14, p = 0.79), progression-free survival (PFS) (HR = 0.92, 95% CI = 0.81–1.06, p = 0.25), and objective response rate (ORR) (HR = 1.08, 95% CI = 0.96–1.21, p = 0.19). Furthermore, the combination immunotherapy was associated increased toxicity as evidenced by increased incidence of any type adverse events (AEs) (RR = 1.06, 95% CI = 1.00–1.13, p = 0.03), grade ≥3 immune-mediated AEs (RR = 1.58, 95% CI = 1.36–1.82, p < 0.05), and treatment discontinuation (RR = 1.83, 95% CI = 1.46–2.28, p < 0.05).Conclusion: Combining anti-CTLA-4 with anti-PD-1/PD-L1 therapy did not improve the therapeutic efficacy, and was associated with greater toxicity than anti-PD-1/PD-L1 monotherapy in patients with advanced NSCLC. Further investigation of the combination immunotherapy in specific subsets of patients is warranted to identify and define the patient-specific benefits of this combination.Systematic Review Registration:https://www.crd.york.ac.uk/prospero/, identifier CRD42023435399

The genus Neocinnamomum is considered to be one of the most enigmatic groups in Lauraceae, mainly distributed in tropical and subtropical regions of Southeast Asia. The genus contains valuable oilseed and medicinal tree species. However, there are few studies on the genus Neocinnamomum at present, and its interspecific relationship is still unclear. In order to explore the genetic structure and evolutionary characteristics of the Neocinnamomum chloroplast genome and to resolve the species relationships within the genus, comparative genomic and phylogenetic analyses were performed on the whole chloroplast genome sequences of 51 samples representing seven Neocinnamomum taxa. The whole Neocinnamomum chloroplast genome size ranged from 150,753-150,956 bp, with a GC content of 38.8%-38.9%. A total of 128 genes were annotated within the Neocinnamomum chloroplast genome, including 84 protein coding genes, 8 rRNA genes, and 36 tRNA genes. Between 71-82 SSRs were detected, among which A/T base repeats were the most common. The chloroplast genome contained a total of 31 preferred codons. Three highly variable regions, trnN-GUU-ndhF, petA-psbJ, and ccsA-ndhD, were identified with Pi values > 0.004. Based on the whole chloroplast genome phylogenetic tree, the phylogenetic relationships among the seven Neocinnamomum taxa were determined. N. delavayi and N. fargesii were the most closely related species, and N. lecomtei was identified as the most basal taxon. In this study, the characteristics and sequence variation of the chloroplast genomes of seven Neocinnamomum taxa were revealed, and the genetic relationship among the species was clarified. The results of this study will provide a reference for subsequent molecular marker development and phylogenetic research of Neocinnamomum.

Pourthiaea is of great ornamental value because it produces white flowers in spring and summer, red fruit in autumn, and their fruit does not fall in winter. In order to explore the genetic structure and evolutionary characteristics of the chloroplast genome of Pourthiaea, comparative genomics analysis and phylogenetic analysis were conducted using ten published chloroplast genomes of Pourthiaea from the NCBI database. The results showed that the chloroplast genomes of the ten species of Pourthiaea showed typical circular tetrad structures, and the genome sizes were all within the range of 160,159–160,401 bp, in which the large single copy was 88,047–88,359 bp, the small single copy was 19,234–19,338 bp, and the lengths of a pair of inverted repeats were 26,341–26,401 bp. The GC contents ranged from 36.5% to 36.6%. A total of 1017 SSR loci were identified from the chloroplast genomes of the ten species of Pourthiaea, including six types of nucleotide repeats. The gene types and gene distribution of the IR boundary regions of the chloroplast genomes of different species of Pourthiaea were highly conservative, with little variation. Through the sequence alignment of chloroplast genomes, it was found that the chloroplast genomes of the ten species of Pourthiaea were generally highly conservative. The variation mainly occurred in the spacer regions of adjacent genes. Through nucleic acid diversity analysis, three hypervariable regions were screened at Pi > 0.006, namely trnQ(UUC)-psbk-psbl, accD-psal, and ndhF-rpl32-trnL (UAG). Phylogenetic analysis showed that the ten species of the genus Pourthiaea were clustered in the same branch and formed sister groups with the genus Stranvaesia, and that the support rate for the monophyly of the genus Pourthiaea was high. This study can serve as a reference for the breeding, genetic evolution, and phylogeny of Pourthiaea.

When the CNC machining of continuous small line segments is performed, the direction of the machine tool movement will change abruptly at the corner of adjacent line segments. Therefore, a reasonable constraint on the feedrate at the corner is the prerequisite for achieving high-speed and high-precision machining. To achieve this goal, a feedrate-constraint method based on the nominal acceleration was proposed. The proposed method obtains the predicted value of acceleration during the machining process by the machining trajectory prediction and acceleration filtering. Then, the feedrate at the corner is constrained, according to the predicted acceleration. Specifically, for any corner of adjacent line segments, the proposed method assumes that the CNC machining of a short path centered on the corner is carried out at a constant feedrate. First, the actual machining trajectory is predicted according to the transfer function of the servo system. Then, the nominal acceleration, when the CNC machining is carried out to the corner, is calculated and processed by a low-pass FIR filter. Last, the feedrate-constraint value at the corner is obtained according to the nominal acceleration and the preset normal acceleration. The advantage of the proposed method is that it can be used for different machining paths consisting of long segments or continuous small segments and it has no special requirement for the accuracy of the machining path. As a result, the feedrate-constraint value obtained is reasonable and the smooth machining process can be ensured. The simulation results in both 2D and 3D machining paths show that the proposed method is insensitive to the length of the line segment and the angle of the corner, and the calculated feedrate-constraint value is close to the theoretical value, which has good stability and versatility. In contrast, the feedrate-constraint values obtained by conventional methods change abruptly along the machining path, especially in the 3D simulation, which will damage the machining quality. The experiment was performed on a three-axis CNC machine tool controlled by a self-developed controller, and a free-form surface workpiece was machined by a conventional feedrate-constraint method and the proposed method, respectively. The experimental results showed that the proposed method can make the feedrate of the machining process higher and more stable. Then, machining defects such as overcutting and undercutting can be avoided and the machining quality can be improved. Therefore, the article proposes a new method to constrain the feedrate at the corner of continuous small line segments, which can improve the machining efficiency and quality of the CNC machining.

The curvature of the NURBS curve varies along its trajectory, therefore, the commonly used feedrate-planning method, which based on the acceleration/deceleration (Acc/Dec) model, is difficult to be directly applied in CNC machining of a NURBS curve. To address this problem, a feedrate-planning method based on the critical constraint curve of the feedrate (CCC) is proposed. Firstly, the problems of existing feedrate-planning methods and their causes are analyzed. Secondly, by considering both the curvature constraint and the kinematic constraint during the Acc/Dec process, the concept of CCC which represents the relationship between the critical feedrate-constraint value and the arc length is proposed. Then the CCC of a NURBS curve is constructed, and it has a concise expression conforming to the Acc/Dec model. Finally, a feedrate-planning method of a NURBS curve based on CCC and the Acc/Dec model is established. In the simulation, a comparison between the proposed method and the conventional feedrate-planning method is performed, and the results show that, the proposed method can reduce the Acc/Dec time by over 40%, while little computational burden being added. The machining experimental results validate the real-time performance and stability of the proposed method, and also the machining quality is verified. The proposed method offers an effective feedrate-planning strategy for a NURBS curve in CNC machining.

The genus Neocinnamomumis considered to be one of themost enigmatic groups in Lauraceae, mainlydistributedintropical andsubtropical regionsofSoutheastAsia. The genus contains valuable oilseed andmedicinal tree species. However, there are few studies on the genus Neocinnamomum at present, and its interspecific relationship is still unclear. In order to explore the genetic structure and evolutionary characteristics of the Neocinnamomum chloroplast genome and to resolve the species relationships within the genus, comparative genomic and phylogenetic analyses were performed on the whole chloroplast genome sequences of 51 samples representing seven Neocinnamomum taxa. The whole Neocinnamomumchloroplast genome size ranged from150,753-150,956 bp, with a GC content of 38.8%-38.9%. A total of 128 genes were annotated within the Neocinnamomumchloroplast genome, including 84 protein coding genes, 8 rRNA genes, and 36 tRNA genes. Between 71-82 SSRs were detected, among which A/T base repeatswere themost common. The chloroplast genome contained a total of 31preferredcodons. Threehighly variableregions, trnN-GUU-ndhF, petA-psbJ, and ccsA-ndhD, were identified with Pi values > 0.004. Based on the whole chloroplast genome phylogenetic tree, the phylogenetic relationships among the seven Neocinnamomum taxa were determined. N. delavayi and N. fargesii were the most closely related species, and N. lecomtei was identified as the most basal taxon. In this study, the characteristics and sequence variation of the chloroplast genomes of seven Neocinnamomum taxa were revealed, and the genetic relationship among the species was clarified. The results of this study will provide a reference for subsequent molecular marker development and phylogenetic research of Neocinnamomum. [ABSTRACT FROM AUTHOR]