A Three-Dimensional Vibration Theory for Ultralight Cellular Sandwich Plates Subjected to Linearly Varying In-Plane Distributed Loads.

Thin structural elements such as large-scale covering plates of aerospace protection structures and vertical stabilizers of aircraft are strongly influenced by gravity (and/or acceleration); thus, exploring how the mechanical behaviors of such structures are affected by gravitational field is necessary. Built upon a zigzag displacement model, this study establishes a three-dimensional vibration theory for ultralight cellular-cored sandwich plates subjected to linearly varying in-plane distributed loads (due to, e.g., hyper gravity or acceleration), with the cross-section rotation angle induced by face sheet shearing accounted for. For selected boundary conditions, the theory enables quantifying the influence of core type (e.g., close-celled metal foams, triangular corrugated metal plates, and metal hexagonal honeycombs) on fundamental frequencies of the sandwich plates. For validation, three-dimensional finite element simulations are carried out, with good agreement achieved between theoretical predictions and simulation results. The validated theory is subsequently employed to evaluate how the geometric parameters of metal sandwich core and the mixture of metal cores and composite face sheets influence the fundamental frequencies. Triangular corrugated sandwich plate possesses the highest fundamental frequency, irrespective of boundary conditions. For each type of sandwich plate considered, the presence of in-plane distributed loads significantly affects its fundamental frequencies and modal shapes.

Spatial patterns of the cap-binding complex eIF4F in human melanoma cells.

As a central node of protein synthesis, the cap-binding complex, eukaryotic translation initiation factor 4 F (eIF4F), is involved in cell homeostasis, development and tumorigenesis. A large body of literature exists on the regulation and function of eIF4F in cancer cells, however the intracellular localization patterns of this complex are largely unknown. Since different subsets of mRNAs are translated in distinct subcellular compartments, understanding the distribution of translation initiation factors in the cell is of major interest. Here, we developed an in situ detection method for eIF4F at the single cell level. By using an image-based spot feature analysis pipeline as well as supervised machine learning, we identify five distinct spatial patterns of the eIF4F translation initiation complex in human melanoma cells. The quantity of eIF4F complex per cell correlated with the global mRNA translation activity, and its variation is dynamically regulated by cell state or extracellular stimuli. In contrast, the spatial patterns of eIF4F complexes at the single cell level could distinguish melanoma cells harboring different oncogenic driver mutations. This suggests that different tumorigenic contexts differentially regulate the subcellular localization of mRNA translation, with specific localization of eIF4F potentially associated with melanoma cell chemoresistance.

A new basic thoracoscopic surgical skill training and assessment system using automatic scoring techniques.

PURPOSE: We report a new thoracoscopic surgical skill training and assessment system with automatic scoring techniques, the Huaxi Intelligent Thoracoscopic Skill Training and Assessment (HITSTA) system. We also evaluated the discriminative ability of this system compared to our conventional scoring method at our institution. METHODS: We retrospectively collected training data of thoracic board-certified thoracic surgeons at West China Hospital, Sichuan University from January 1, 2018 to January 1, 2019. Surgeons were assessed by HITSTA system and human examiners simultaneously. Total scores were summed from 3 tasks (grasping with delivery, pattern cutting, and suture with knot). Bland-Altman analysis was used to test agreement of scores made by HITSTA system (automatic scoring) and human examiners (manual scoring). Differentiation ability was also compared between the two scoring methods. RESULTS: Thirty-nine surgeons were recruited. Scores made by HITSTA system and human examiners were not consistent. For suture with knot, automatic scoring method could detect the score differences between different training status (trained: 26.92 ± 12.04, untrained: 19.85 ± 11.12; p = 0.026) and training duration (< 10 h: 20.67 ± 15.23, ≥ 10 h: 31.92 ± 5.56; p = 0.003). For total scores, automatic scoring approach could discriminate between different training status (trained: 71.90 ± 12.63; untrained: 61.41 ± 13.87; p = 0.016) and training duration (< 10 h: 65.23 ± 15.31; ≥ 10 h 77.23 ± 6.94; p = 0.046). CONCLUSION: HITSTA system could discriminate the different levels of thoracoscopic surgical skills better than the traditional manual scoring method. Larger prospective studies are warranted to validate the differentiation ability of HITSTA system.

Electrocautery vs. Stapler in Comparing Safety for Segmentectomy of Lung Cancer: A Meta-Analysis.

Background: Electrocautery and staplers are regarded as the two most common surgical instruments for dissecting the intersegmental plane in segmentectomy. We performed a meta-analysis to compare electrocautery and staplers in terms of their safety and effects. Methods: A systematic search strategy was performed using PubMed, and the retrieval time was up to April 1, 2020. Odds ratio (OR) and mean differences (MDs) with 95% CI were applied to determine the effectiveness of dichotomous or continuous variables, respectively. Results: Six studies including 385 patients were included. The electrocautery had a higher incidence rate of postoperative complication [OR= 1.92, 95% CI (1.12, 3.28), P = 0.02)] and air leak [OR: 3.91, 95% CI (1.64, 9.35), P = 0.002)]. No significant difference was found in the comparison of surgery time, blood loss, and duration of tube days or hospitality days. Conclusions: Our study indicated that patients under segmentectomy were associated with better safety by using stapler than electrocautery in the reduction of postoperative complications.

Knockdown of miR-15b partially reverses the cisplatin resistance of NSCLC through the GSK-3ß/MCL-1 pathway.

BACKGROUND: Induction of acquired drug resistance occurs frequently with cisplatin-based therapy for non-small cell lung cancer (NSCLC). As recent studies have demonstrated that deregulation of microRNAs (miRNAs) is associated with drug resistance in cancers, correcting the deregulation of miRNAs represents a promising strategy to reverse acquired resistance in NSCLC. OBJECTIVES: This study investigated the functional role of miR-15b in cisplatin resistance in NSCLC. MATERIAL AND METHODS: Cisplatin-resistant PC9 and A549 NSCLC cell lines (PC9-R and A549-R) were established through long-term exposure to cisplatin. Differences in miR-15b expression between cisplatin-resistant NSCLC cell lines and their parental cell lines were identified through quantitative real-time polymerase chain reaction (qRT-PCR). The effect of anti-miR-15b on the sensitivity of PC9-R and A549-R to cisplatin-induced cytotoxicity was evaluated using Cell Counting Kit-8 (CCK-8) assays. Regulation of GSK-3ß by miR-15b was confirmed with luciferase reporter assays. Cell apoptosis and mitochondrial membrane potential (MMP) were measured using flow cytometry analysis. RESULTS: In PC9-R and A549-R cells, miR-15b was significantly overexpressed. However, knockdown of miR-15b clearly reduced cisplatin resistance in PC9-R and A549-R cells. Researching the mechanism, we proved that GSK-3ß was the target of miR-15b. Knockdown of miR-15b significantly increased the expression GSK-3ß and thus promoted the degradation of MCL-1, which is a key anti-apoptosis protein. As a result, anti-miR-15b expanded the cisplatin-induced apoptosis in cisplatin-resistant NSCLC cells. CONCLUSIONS: Knockdown of miR-15b partially reversed cisplatin resistance in NSCLC cells through the GSK-3ß/MCL-1 pathway.

Thermal Volume Reduction Surgery for Surgical Treatment of Pulmonary Bullae: A Single-Center Treatment Experience of 276 Cases Accompany With Primary Lung Cancer.

Objective: Lung volume reduction surgery (LVRS) has been regarded as an effective surgical procedure for severe emphysema (including pulmonary bullae). However, there still remain controversial that its applications limited that only patients with a specific clinical situation may benefit from LVRS, and so did other non-surgical treatments. The current study aims to introduce some initial experience of new technique for treating pulmonary bullae, including using thermal surgical instruments to reduce enlargement of lung tissue in a specific group that diagnosed with lung cancer accompany with pulmonary bullae. Methods: This retrospective study included 276 patients undergoing emphysema reducing surgery between 2010 and 2020. All procedure were performed by thermal volume reduction surgery of using thermal surgical instruments to reduce pulmonary bullae. Results: The average time required for operating single pulmonary bullae was <10 min. Median operative time was 106 min (range 85 to 191 min). No intraoperative air leak, massive blood loss, or other severe complications occurred. The estimated blood loss for TVRS was about 40 ml (range 15 to 120 ml). Postoperative complications included atelectasis (n = 8), pulmonary infection (n = 17), bleeding (n = 5), delayed air leak (n = 7) among the cohort. The postoperative lung function at 1-year post surgery in TVRS group recovered faster with a better recovery that achieving an FEV1 of 1.95 ± 0.46 L, TLC of 6.36 ± 0.79 L, RV of 3.56 ± 0.81 L, PO2 of 60 ± 8 mmHg, PCO2 of 37 ± 6 mmHg, and 6 MWD (6-min walk distant) of 305 ± 22 m. The 1-year QOL score was elevated comparing with preoperative period. Conclusion: This single-center study reported a new thermal-based surgical approach to treat pulmonary bullae by reducing abnormally enlarged lung tissue in specific patients diagnosed with lung cancer accompany with pulmonary bullae.

Eriodictyol inhibits high glucose-induced oxidative stress and inflammation in retinal ganglial cells.

Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes mellitus and is considered as a leading cause of blindness. Oxidative stress and inflammation are significant drivers for the development of DR. Eriodictyol, a flavonoid compound, was proved to possess anti-inflammatory, antioxidative, and antidiabetic activities. However, the role of eriodictyol in DR has not been unveiled. In the current study, we explored the protective effects of eriodictyol on high glucose (HG)-induced rat retinal ganglial cells (RGCs). The results suggested that eriodictyol improved cell viability of HG-induced rat RGC-5 cells in a dose-dependent manner. Eriodictyol reduced the reactive oxygen species production and increased the activities of superoxide dismutase, glutathione peroxidase and catalase in rat RGC-5 cells in response to HG stimulation. The production of proinflammatory cytokines including tumor necrosis factor alpha and interleukin-8 was diminished after eriodictyol treatment. Eriodictyol also suppressed cell apoptosis induced HG in rat RGC-5 cells. Furthermore, eriodictyol enhanced the nuclear translocation of nuclear factor erythroid-2 (E2)-related factor 2 (Nrf2) and elevated the expression of antioxidant enzyme heme-oxygenase-1 (HO-1). These findings suggested that eriodictyol protects the RGC-5 cells from HG-induced oxidative stress, inflammation, and cell apoptosis through regulating the activation of Nrf2/HO-1 pathway.

[The Development of Huaxi Intelligent Endoscopic Skill Training and Assessment System].

OBJECTIVE: To develop a novel objective standardized endoscopic skill training and assessment system based on artificial intelligence technology. METHODS: By designing five basic skill parts of endoscopic operation including vision location, clamping, delivering, shearing and suturing, we achieved objective standardized indexes which gained automatically with image recognition and refined perception. RESULTS: With Huaxi intelligent endoscopic skill training system, the accurate rates of vision location, clamping, delivering, shearing and suturing were 90%, 95%, 99%, 90%, and 89%, respectively. The response and performance time were 8-10 s, <1 s, <1 s, 1-3 s, and <1 s, respectively. CONCLUSION: Huaxi intelligent endoscopic skill training and assessment system has preliminarily possessed the capability to assess the endoscopic skills of surgeons objectively.

Sound absorption by acoustic microlattice with optimized pore configuration.

The great progress in material science and nano-micro fabrication enables the applications of metamaterials with well-defined and well-organized microstructures for noise reduction. However, what intrinsic morphology of the metamaterial would result in optimum sound absorbing efficiency remains uncertain. This work presents a microlattice metamaterial, comprising well-defined and organized material morphology in terms of pore size and porosity, for generating optimum sound dissipation. A compact governing equation is established and verified experimentally to show that the optimum sound absorption can only be reached when the pore size equals twice the thickness of a viscous boundary layer.

Advances in the application of 3D printing technology in chest wall disease surgery / 中国胸心血管外科临床杂志

@#Because of the characteristics such as accurate, efficient and individuation, 3D printing is being widely applied to manufacturing industry, and being gradually expanded into the medical field. Diseases of chest wall is a common type in thoracic surgery, and surgery is a proper treatment to this kind of disease. For the past few years, 3D printing is being gradually applied in surgery of chest wall diseases. The article mainly makes a statement of two parts that including the possibility to apply 3D printing including chest wall reconstruction and chest wall orthopedic, and to analyze the possibility and application prospect of applying 3D printing to the chest wall disease.

Diffraction phase microscopy imaging and multi-physics modeling of the nanoscale thermal expansion of a suspended resistor.

We studied the nanoscale thermal expansion of a suspended resistor both theoretically and experimentally and obtained consistent results. In the theoretical analysis, we used a three-dimensional coupled electrical-thermal-mechanical simulation and obtained the temperature and displacement field of the suspended resistor under a direct current (DC) input voltage. In the experiment, we recorded a sequence of images of the axial thermal expansion of the central bridge region of the suspended resistor at a rate of 1.8 frames/s by using epi-illumination diffraction phase microscopy (epi-DPM). This method accurately measured nanometer level relative height changes of the resistor in a temporally and spatially resolved manner. Upon application of a 2 V step in voltage, the resistor exhibited a steady-state increase in resistance of 1.14 Ω and in relative height of 3.5 nm, which agreed reasonably well with the predicted values of 1.08 Ω and 4.4 nm, respectively.

Clinical characteristics and outcomes of lung cancer patients with combined pulmonary fibrosis and emphysema: a systematic review and meta-analysis of 13 studies.

BACKGROUND: The characteristic and outcomes of lung cancer patients with combined pulmonary fibrosis and emphysema (CPFE) have long been assessed, but results were controversial. Therefore, we performed a meta-analysis to assess the clinical features and prognosis of lung cancer patients with CPFE. METHODS: The databases PubMed, Embase, and Web of Science (updated to October 1, 2017) were searched for eligible studies. Pooled odds ratios (ORs), weighted mean differences (WMD) or hazard ratios (HRs) with 95% confidence intervals (95% CIs) were used to evaluate the clinicopathological characteristics, the short-term outcome after operation and long-term survival of lung cancer patients with CPFE compared with lung cancer patients without CPFE (fibrosis, emphysema, and normal). RESULTS: Thirty original studies with 8,050 patients were included in this meta-analysis. The pooled results indicated that lung cancer patients with CPFE were associated with higher age (MD =3.39; 95% CI: 2.12-4.67, P<0.001), male (OR =8.46; 95% CI: 6.36-11.26, P<0.001), ex- or current smoker (OR =39.65; 95% CI: 15.64-100.5, P<0.001), longer smoking history (MD =15.56; 95% CI: 3.73-27.39, P=0.01), lower DLCO% (MD =-13.82; 95% CI: -21.4 to -6.24, P<0.001), squamous cell carcinoma histology (OR =3.55; 95% CI: 2.49-5.05, P<0.001), the lower lobes (OR =1.92; 95% CI: 1.52-2.43, P<0.001), advanced pathological stage (OR =1.55; 95% CI: 1.22-1.96, P<0.001). Lung cancer patients with CPFE had higher 30-day mortality (OR =4.72, 95% CI: 2.06-10.85, P<0.001), 90-day mortality (OR =5.33; 95% CI: 1.39-20.42, P=0.01), and incidence of postoperative complications (OR =5.25, 95% CI: 2.38-11.57, P<0.001). In addition, the lung cancer patients with CPFE had a poorer OS (HR =2.006, 95% CI: 1.347-2.986, P=0.001) than lung cancer patients without CPFE. CONCLUSIONS: This meta-analysis demonstrated that lung cancer patients with CPFE have more aggressive clinical characteristic and a poor prognosis, suggesting that lung cancer patients with CPFE should be early detected, treated reasonably and be taken good care of.

Tensional acoustomechanical soft metamaterials.

We create acoustomechanical soft metamaterials whose response to uniaxial tensile stressing can be easily tailored by programming acoustic wave inputs, resulting in force versus stretch curves that exhibit distinct monotonic, s-shape, plateau and non-monotonic snapping behaviors. We theoretically demonstrate this unique metamaterial by considering a thin soft material sheet impinged by two counter-propagating ultrasonic wave inputs across its thickness and stretched by an in-plane uniaxial tensile force. We establish a theoretical acoustomechanical model to describe the programmable mechanics of such soft metamaterial, and introduce the first- and second-order tangential stiffness of its force versus stretch curve to boundary different behaviors that appear during deformation. The proposed phase diagrams for the underlying nonlinear mechanics show promising prospects for designing tunable and switchable photonic/phononic crystals and microfluidic devices that harness snap-through instability.

Plastic Deformation Modes of CuZr/Cu Multilayers.

We synthesized CuZr/Cu multilayers and performed nanoindentation testing to explore the dependence of plastic deformation modes on the thickness of CuZr layers. The Cu layers were 18 nm thick and the CuZr layers varied in thickness from 4 nm to 100 nm. We observed continuous plastic co-deformation in the 4 nm and 10 nm CuZr - 18 nm Cu multilayers and plastic-induced shear instability in thick CuZr layers (>20 nm). The plastic co-deformation is ascribed to the nucleation and interaction of shear transformation zones in CuZr layers at the adjacent interfaces, while the shear instability is associated with the nucleation and propagation of shear bands in CuZr layers. Shear bands are initialized in the CuZr layers due to the accumulated glide dislocations along CuZr-Cu interfaces, and propagate into adjacent Cu layers via slips on {111} plane non-parallel to the interface. Due to crystallographic constraint of the Cu layers, shear bands are approximately parallel to {111} plane in the Cu layer.

Microbubble embedded with upconversion nanoparticles as a bimodal contrast agent for fluorescence and ultrasound imaging.

Bimodal imaging offers additional imaging signal thus finds wide spread application in clinical diagnostic imaging. Fluorescence/ultrasound bimodal imaging contrast agent using fluorescent dyes or quantum dots for fluorescence signal has emerged as a promising method, which however requires visible light or UV irradiation resulting in photobleaching, photo blinking,auto-fluorescence and limited tissue penetration depth. To surmount these problems, we developed a novel bimodal contrast agent using layer-by-layer assembly of up conversion nanoparticles onto the surface of microbubbles. The resulting microbubbles with average size of 2 µm provide enhanced ultrasound echo for ultrasound imaging and upconversion emission upon near infrared irradiation for fluorescence imaging. The developed bimodal contrast agent holds great potential to be applied in ultrasound target technique for targeted diseases diagnostics and therapy.

Molecular analysis of interactions between a PAMAM dendrimer-paclitaxel conjugate and a biomembrane.

Understanding the underlying mechanism of nanomedicine-biomembrane interactions is important for the design and optimization of payload delivery systems. This study investigates the interactions between polyamidoamine (PAMAM) dendrimer-paclitaxel conjugates and biomembranes using coarse-grained molecular dynamics simulations. We found that acidic conditions (e.g., pH ∼ 5) and membrane asymmetry can improve the conjugate penetration. Paclitaxel (PTX) distributions on a G4 PAMAM dendrimer can affect interactions via the penetration mechanism, although they have no significant effect on interactions via the adsorption mechanism. The random distribution of PTX can enhance the ability of PTX molecules to pass through asymmetric membranes. Furthermore, the penetration process becomes more difficult with increasing paclitaxel loading ratios. These results provide molecular insights into the precise translocation mechanism of dendrimer-drug conjugates and thus provide suggestions for drug design and delivery.

Thermal Pain in Teeth: Electrophysiology Governed by Thermomechanics.

Thermal pain arising from the teeth is unlike that arising from anywhere else in the body. The source of this peculiarity is a long-standing mystery that has begun to unravel with recent experimental measurements and, somewhat surprisingly, new thermomechanical models. Pain from excessive heating and cooling is typically sensed throughout the body through the action of specific, heat sensitive ion channels that reside on sensory neurons known as nociceptors. These ion channels are found on tooth nociceptors, but only in teeth does the pain of heating differ starkly from the pain of cooling, with cold stimuli producing more rapid and sharper pain. Here, we review the range of hypotheses and models for these phenomena, and focus on what is emerging as the most promising hypothesis: pain transduced by fluid flowing through the hierarchical structure of teeth. We summarize experimental evidence, and critically review the range of heat transfer, solid mechanics, fluid dynamics, and electrophysiological models that have been combined to support this hypothesis. While the results reviewed here are specific to teeth, this class of coupled thermomechanical and neurophysiological models has potential for informing design of a broad range of thermal therapies and understanding of a range of biophysical phenomena.