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BACKGROUND: Despite centuries of traditional use of silymarin for hepatoprotection, current randomized controlled trial (RCT) studies on the effectiveness of silymarin in managing metabolic dysfunction-associated steatotic liver disease (MASLD) are limited and inconclusive, particularly when it is administered alone. The low bioavailability of silymarin highlights the possible influence of gut microbiota on the effectiveness of silymarin; however, no human studies have investigated this aspect. OBJECTIVE: To determine the potential efficacy of silymarin in improving MASLD indicators and to investigate the underlying mechanisms related to gut microbiota. METHOD: In this 24-week randomized, double-blind, placebo-controlled trial, 83 patients with MASLD were randomized to either placebo (n = 41) or silymarin (103.2 mg/d, n = 42). At 0, 12, and 24 weeks, liver stiffness and hepatic steatosis were assessed using FibroScan, and blood samples were gathered for biochemical detection, while faecal samples were collected at 0 and 24 weeks for 16S rRNA sequencing. RESULTS: Silymarin supplementation significantly reduced liver stiffness (LSM, -0.21 ± 0.17 vs. 0.41 ± 0.17, P = 0.015) and serum levels of γ-glutamyl transpeptidase (GGT, -8.21 ± 3.01 vs. 1.23 ± 3.16, P = 0.042) and ApoB (-0.02 ± 0.03 vs. 0.07 ± 0.03, P = 0.023) but had no significant effect on the controlled attenuation parameter (CAP), other biochemical indicators (aminotransferases, total bilirubin, glucose and lipid parameters, hsCRP, SOD, and UA), physical measurements (DBP, SBP, BMI, WHR, BF%, and BMR), or APRI and FIB-4 indices. Gut microbiota analysis revealed increased species diversity and enrichment of Oscillospiraceae in the silymarin group. CONCLUSION: These findings suggest that silymarin supplementation could improve liver stiffness in MASLD patients, possibly by modulating the gut microbiota. TRIAL REGISTRATION: The trial was registered at the Chinese Clinical Trial Registry (ChiCTR2200059043).
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Microbioma Gastrointestinal , Fígado , Silimarina , Humanos , Silimarina/farmacologia , Silimarina/uso terapêutico , Silimarina/administração & dosagem , Microbioma Gastrointestinal/efeitos dos fármacos , Masculino , Feminino , Pessoa de Meia-Idade , Método Duplo-Cego , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Adulto , Fígado Gorduroso/tratamento farmacológico , Suplementos Nutricionais , RNA Ribossômico 16S/genética , Técnicas de Imagem por Elasticidade , IdosoRESUMO
Stem cells possess exceptional proliferation and differentiation abilities, making them highly promising for targeted recruitment research in tissue engineering and other clinical applications. DNA is a naturally water-soluble, biocompatible, and highly editable material that is widely used in cell recruitment research. However, DNA nanomaterials face challenges, such as poor stability, complex synthesis processes, and demanding storage conditions, which limit their potential applications. In this study, we designed a highly stable DNA nanomaterial that embeds nucleic acid aptamers in the single strand region. This material has the ability to specifically bind, recruit, and capture human mesenchymal stem cells. The synthesis process involves rolling circle amplification and topological isomerization, and it can be stored for extended periods under varying temperatures and humidity conditions. This DNA material offers high specificity, ease of fabrication, simple preservation, and low cost, providing a novel approach to stem cell recruitment strategies.
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Aptâmeros de Nucleotídeos , Nanoestruturas , Humanos , DNA , Engenharia TecidualRESUMO
BACKGROUND: The standard therapy for women with unexplained infertility is gonadotropin or clomiphene citrate. Ovarian stimulation with letrozole has been proposed to reduce multiple gestations while maintaining live birth rates. METHODS: We enrolled couples with unexplained infertility in a multicenter, randomized trial. Ovulatory women 18 to 40 years of age with at least one patent fallopian tube were randomly assigned to ovarian stimulation (up to four cycles) with gonadotropin (301 women), clomiphene (300), or letrozole (299). The primary outcome was the rate of multiple gestations among women with clinical pregnancies. RESULTS: After treatment with gonadotropin, clomiphene, or letrozole, clinical pregnancies occurred in 35.5%, 28.3%, and 22.4% of cycles, and live birth in 32.2%, 23.3%, and 18.7%, respectively; pregnancy rates with letrozole were significantly lower than the rates with standard therapy (gonadotropin or clomiphene) (P=0.003) or gonadotropin alone (P<0.001) but not with clomiphene alone (P=0.10). Among ongoing pregnancies with fetal heart activity, the multiple gestation rate with letrozole (9 of 67 pregnancies, 13%) did not differ significantly from the rate with gonadotropin or clomiphene (42 of 192, 22%; P=0.15) or clomiphene alone (8 of 85, 9%; P=0.44) but was lower than the rate with gonadotropin alone (34 of 107, 32%; P=0.006). All multiple gestations in the clomiphene and letrozole groups were twins, whereas gonadotropin treatment resulted in 24 twin and 10 triplet gestations. There were no significant differences among groups in the frequencies of congenital anomalies or major fetal and neonatal complications. CONCLUSIONS: In women with unexplained infertility, ovarian stimulation with letrozole resulted in a significantly lower frequency of multiple gestation but also a lower frequency of live birth, as compared with gonadotropin but not as compared with clomiphene. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT01044862.).
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Clomifeno/uso terapêutico , Fármacos para a Fertilidade Feminina/uso terapêutico , Gonadotropinas/uso terapêutico , Infertilidade Feminina/tratamento farmacológico , Nitrilas/uso terapêutico , Indução da Ovulação/métodos , Gravidez Múltipla/estatística & dados numéricos , Triazóis/uso terapêutico , Adolescente , Adulto , Feminino , Humanos , Letrozol , Nascido Vivo/epidemiologia , Gravidez , Taxa de Gravidez , Adulto JovemRESUMO
Recently, stretchable electronics have been highly desirable in the Internet of Things and electronic skins. Herein, an innovative and cost-efficient strategy is demonstrated to fabricate highly sensitive, stretchable, and conductive strain-sensing platforms inspired by the geometries of a spiders slit organ and a lobsters shell. The electrically conductive composites are fabricated via embedding the 3D percolation networks of fragmentized graphene sponges (FGS) in poly(styrene-block-butadiene-block-styrene) (SBS) matrix, followed by an iterative process of silver precursor absorption and reduction. The slit- and scale-like structures and hybrid conductive blocks of FGS and Ag nanoparticles (NPs) provide the obtained FGS-Ag-NP-embedded composites with superior electrical conductivity of 1521 S cm-1 , high break elongation of 680%, a wide sensing range of up to 120% strain, high sensitivity of ≈107 at a strain of 120%, fast response time of ≈20 ms, as well as excellent reliability and stability of 2000 cycles. This huge stretchability and sensitivity is attributed to the combination of high stretchability of SBS and the binary synergistic effects of designed FGS architectures and Ag NPs. Moreover, the FGS/SBS/Ag composites can be employed as wearable sensors to detect the modes of finger motions successfully, and patterned conductive interconnects for flexible arrays of light-emitting diodes.
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Eletrônica , Grafite/química , Nanopartículas Metálicas/química , Prata/químicaRESUMO
This paper proposes a system-in-package combination navigation chip. We used wire bonding, chip stacking, surface mount, and other processes to integrate satellite navigation chips, inertial navigation chips, microprocessor chips, and separation devices. Finally, we realized the hardware requirements for combined navigation in a 20 mm × 20 mm chip. Further, we performed a multi-physics simulation analysis of the package design. For antenna signals, the insertion loss was greater than -1 dB@1 GHz and the return loss was less than -10 dB@1 GHz. The amplitude of these noises of the signal between the MCU and the IMU was approximately 20%, and the maximum value of the coupling coefficient between signal lines on the top surface was 13.4174%. The ninth mode of the power plane yielded a maximum voltage of 55 mV, and all power delivery networks had a DC voltage drop of less than 2%. The highest temperature in the microsystem was approximately 42 °C. These results show that our design performed well in terms of signal, power, and thermal performance.
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To address the requirements of sonar imaging, such as high receiving sensitivity, a wide bandwidth, and a wide receiving angle, an AlN PMUT with an optimized ratio of 0.6 for the piezoelectric layer diameter to backside cavity diameter is proposed in this paper. A sample AlN PMUT is designed and fabricated with the SOI substrate-based bulk MEMS process. The characterization test result of the sample demonstrates a -6 dB bandwidth of approximately 500 kHz and a measured receiving sensitivity per unit area of 1.37 V/µPa/mm2, which significantly surpasses the performance of previously reported PMUTs. The -6 dB horizontal angles of the AlN PMUT at 300 kHz and 500 kHz are measured as 68.30° and 54.24°, respectively. To achieve an accurate prediction of its characteristics when being packaged and assembled in a receive array, numerical simulations with the consideration of film stress are conducted. The numerical result shows a maximum deviation of ±7% in the underwater receiving sensitivity across the frequency range of 200 kHz to 1000 kHz and a deviation of about 0.33% in the peak of underwater receiving sensitivity compared to the experimental data. By such good agreement, the simulation method reveals its capability of providing theoretical foundation for enhancing the uniformity of AlN PMUTs in future studies.
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Correction for 'An interfacial toughening strategy for high stability 2D/3D perovskite X-ray detectors with a carbon nanotube thin film electrode' by Liwen Qiu et al., Nanoscale, 2023, 15, 14574-14583, https://doi.org/10.1039/D3NR02801A.
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Wearable and implantable devices have gained significant popularity, playing a crucial role in smart healthcare and human-machine interfaces, which necessitates the development of more complex electronic devices and circuits on biocompatible flexible materials. Polylactic acid (PLA) stands out due to its biodegradability, cost-effectiveness, and low immunogenicity. In this study, we utilize a solution-based spin-coating method to produce high-quality PLA thin films, serving as substrates for the fabrication of thin-film transistors (TFTs) in which the dielectric layer material is silicon dioxide, the channel layer material is IGZO, and the gate, drain, and source material is ITO at low temperatures (<40 °C) through a shadow masking technique. The resulting PLA-TFT devices exhibited remarkable flexibility, biocompatibility, and impressive electrical characteristics, including a charge carrier mobility of 27.81 cm2/(V s), a subthreshold swing of 162.8 mV/decade, and an ON/OFF current ratio of up to 1 × 106, and maintained performance under various deformations. We successfully constructed fundamental logic gate circuits using PLA-TFTs, including AND, OR, and NOT gates, which effectively performed logical functions and demonstrated stability under diverse bending conditions. These research findings provide valuable support for future endeavors in fabricating intricate logic circuits and realizing advanced functionalities on biocompatible flexible materials.
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Resveratrol (RES) has been reported to prevent hyperuricemia (HUA); however, its effect on intestinal uric acid metabolism remains unclear. This study evaluated the impact of RES on intestinal uric acid metabolism in mice with HUA induced by a high-fat diet (HFD). Moreover, we revealed the underlying mechanism through metagenomics, fecal microbiota transplantation (FMT), and 16S ribosomal RNA analysis. We demonstrated that RES reduced the serum uric acid, creatinine, urea nitrogen, and urinary protein levels, and improved the glomerular atrophy, unclear renal tubule structure, fibrosis, and renal inflammation. The results also showed that RES increased intestinal uric acid degradation. RES significantly changed the intestinal flora composition of HFD-fed mice by enriching the beneficial bacteria that degrade uric acid, reducing harmful bacteria that promote inflammation, and improving microbial function via the upregulation of purine metabolism. The FMT results further showed that the intestinal microbiota is essential for the effect of RES on HUA, and that Lactobacillus may play a key role in this process. The present study demonstrated that RES alleviates HFD-induced HUA and renal injury by regulating the gut microbiota composition and the metabolism of uric acid.
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Microbioma Gastrointestinal , Hiperuricemia , Animais , Camundongos , Hiperuricemia/tratamento farmacológico , Resveratrol/farmacologia , Ácido Úrico , Túbulos Renais , InflamaçãoRESUMO
Silymarin, salvianolic acids B, and puerarin were considered healthy food agents with tremendous potential to ameliorate non-alcoholic fatty liver disease (NAFLD). However, the mechanisms by which they interact with gut microbiota to exert benefits are largely unknown. After 8 weeks of NAFLD modeling, C57BL/6J mice were randomly divided into five groups and fed a normal diet, high-fat diet (HFD), or HFD supplemented with a medium or high dose of Silybum marianum extract contained silymarin or polyherbal extract contained silymarin, salvianolic acids B, and puerarin for 16 weeks, respectively. The untargeted metabolomics and 16S rRNA sequencing were used for molecular mechanisms exploration. The intervention of silymarin and polyherbal extract significantly improved liver steatosis and recovered liver function in the mice, accompanied by an increase in probiotics like Akkermansia and Blautia, and suppressed Clostridium, which related to changes in the bile acids profile in feces and serum. Fecal microbiome transplantation confirmed that this alteration of microbiota and its metabolites were responsible for the improvement in NAFLD. The present study substantiated that alterations of the gut microbiota upon silymarin and polyherbal extract intervention have beneficial effects on HFD-induced hepatic steatosis and suggested the pivotal role of gut microbiota and its metabolites in the amelioration of NAFLD.
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Depsídeos , Dieta Hiperlipídica , Suplementos Nutricionais , Microbioma Gastrointestinal , Isoflavonas , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica , Silimarina , Animais , Microbioma Gastrointestinal/efeitos dos fármacos , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Dieta Hiperlipídica/efeitos adversos , Isoflavonas/farmacologia , Masculino , Camundongos , Silimarina/farmacologia , Benzofuranos/farmacologia , Fígado/metabolismo , Fígado/efeitos dos fármacos , Modelos Animais de Doenças , Ácidos e Sais Biliares/metabolismo , Extratos Vegetais/farmacologiaRESUMO
Plastics are widely used in human daily life, which bring great convenience. Nevertheless, the disposal of a large amount of plastic wastes also brings great pressure to the environment. Polyethylene terephthalate (PET) is a polymer thermoplastic material produced from petroleum. It has become one of the most commonly used plastics in the world due to its durability, high transparency, light weight and other characteristics. PET can exist in nature for a long time due to its complex structure and the difficulty in degradation, which causes serious pollution to the global ecological environment, and threatens human health. The degradation of PET wastes has since become one of the global challenges. Compared with physical and chemical methods, biodegradation is the greenest way for treating PET wastes. This review summarizes the recent advances on PET biodegradation including microbial and enzymatic degradation of PET, biodegradation pathway, biodegradation mechanisms, and molecular modification of PET-degrading enzymes. In addition, the prospect for achieveing efficient degradation of PET, searching and improving microorganisms or enzymes that can degrade PET of high crystallinity are presented, with the aimto facilitate the development, application and molecular modification of PET biodegradation microorganisms or enzymes.
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Petróleo , Polietilenotereftalatos , Humanos , Polietilenotereftalatos/metabolismo , Polímeros , Biodegradação AmbientalRESUMO
The decreasing-width, increasing-aspect-ratio RDL presents significant challenges to the design for reliability (DFR) of an advanced package. Therefore, this paper proposes an ML-based RDL modeling and simulation method. In the method, RDL was divided into blocks and subdivided into pixels of metal percentage, and the RDL was digitalized as tensors. Then, an ANN-based surrogate model was built and trained using a subset of tensors to predict the equivalent material properties of each block. Lastly, all blocks were transformed into elements for simulations. For validation, line bending simulations were conducted on an RDL, with the reaction force as an accuracy indicator. The results show that neglecting layout impact caused critical errors as the substrate thinned. According to the method, the reaction force error was 2.81% and the layout impact could be accurately considered with 200 × 200 elements. For application, the TCT maximum temperature state simulation was conducted on a CPU chip. The simulation indicated that for an advanced package, the maximum stress was more likely to occur in RDL rather than in bumps; both RDL and bumps were critically impacted by layouts, and RDL stress was also impacted by vias/bumps. The proposed method precisely concerned layout impacts with few resources, presenting an opportunity for efficient improvement.
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Resveratrol is a polyphenol with a well-established beneficial effect on dyslipidemia and hyperuricemia in preclinical experiments. Nonetheless, its efficacy and dose-response relationship in clinical trials remains unclear. This study examined whether resveratrol supplement improves the serum lipid profile and other metabolic markers in a dose-response manner in individuals with dyslipidemia. A total of 168 subjects were randomly assigned to placebo (n = 43) and resveratrol treatment groups of 100 mg/d (n = 41), 300 mg/d (n = 43), and 600 mg/d (n = 41). Anthropometric and biochemical parameters were analyzed at baseline and 4 and 8 weeks. Resveratrol supplementation for 8 weeks did not significantly change the lipid profile compared with the placebo. However, a significant decrease of serum uric acid was observed at 8 weeks in 300 mg/d (-23.60 ± 61.53 µmol/L, p < 0.05) and 600 mg/d resveratrol groups (-24.37 ± 64.24 µmol/L, p < 0.01) compared to placebo (8.19 ± 44.60 µmol/L). Furthermore, xanthine oxidase (XO) activity decreased significantly in the 600 mg/d resveratrol group (-0.09 ± 0.29 U/mL, p < 0.05) compared with placebo (0.03 ± 0.20 U/mL) after 8 weeks. The reduction of uric acid and XO activity exhibited a dose-response relationship (p for trend, <0.05). Furthermore, a marked correlation was found between the changes in uric acid and XO activity in the resveratrol groups (r = 0.254, p < 0.01). Resveratrol (10 µmol/L) treatment to HepG2 cells significantly reduced the uric acid levels and intracellular XO activity. Nevertheless, we failed to detect significant differences in glucose, insulin, or oxidative stress biomarkers between the resveratrol groups and placebo. In conclusion, resveratrol supplementation for 8 weeks had no significant effect on lipid profile but decreased uric acid in a dose-response manner, possibly due to XO inhibition in subjects with dyslipidemia. The trial was registered on ClinicalTrials.gov (NCT04886297).
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Dislipidemias , Ácido Úrico , Humanos , Resveratrol , Suplementos Nutricionais , Lipídeos , Dislipidemias/tratamento farmacológico , Método Duplo-CegoRESUMO
Parylene C has been widely used in the fields of microelectromechanical systems (MEMS) and electronic device encapsulation because of its unique properties, such as biocompatibility and conformal coverage. However, its poor adhesion and low thermal stability limit its use in a wider range of applications. This study proposes a novel method for improving the thermal stability and enhancing the adhesion between Parylene and Si by copolymerizing Parylene C with Parylene F. The successful preparation of Parylene copolymer films containing different ratios of Parylene C and Parylene F was confirmed using Fourier-transform infrared spectroscopy and surface energy calculations. The proposed method resulted in the copolymer film having an adhesion 10.4 times stronger than that of the Parylene C homopolymer film. Furthermore, the friction coefficients and cell culture capability of the Parylene copolymer films were tested. The results indicated no degradation compared with the Parylene C homopolymer film. This copolymerization method significantly expands the applications of Parylene materials.
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Single-crystalline metal halide perovskite materials hold great promise for developing next-generation low-dose X-ray detection. To bring this new technology into reality, it is important to improve the durability of perovksite detectors by suppressing the well-known corrosion and ion diffusion problems at the perovskite/electrode interface. For imaging application, it is also imperative to develop new assembling approaches to realise non-planar interconnection between thick perovskite crystals and thin-film transistor (TFT) backplanes. Herein, a flexible and mechanically robust carbon nanotube (CNT) film was proposed to replace noble metal electrodes. The proposed CNT film, whose binder contains a carboxyl group, can form solid contact with a phenethylamine-based two-dimensional (2D) perovskite via amide coupling, thus toughening the perovskite-electrode interface. The resulting CNT/2D-3D perovskite detector shows an applaudable low dark current, high sensitivity, a low dose detection limit and excellent stability, retaining 98% of its initial sensitivity after storage for three months. Moreover, the flexible CNT films are also beneficial for making non-planar interconnection between thick perovskite crystals and TFT backplanes. The proposed flexible CNT thin film electrode thus provides a facile route towards realising a low-dose, high-resolution and highly stable perovskite X-ray detector.
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A novel fiber reference optical readout method was proposed in the bi-material micro cantilever infrared imaging system, which consists of an infrared imaging channel, an optical readout channel and a fiber reference channel. The fiber reference channel is used to monitor the intensity fluctuation of the light source, and provide a signal to correct the distortion of the infrared images from the optical readout channel. Comparing with the typical optical readout method without any references, the noise equivalent temperature difference (NETD) of such an infrared imaging system with the fiber reference optical readout method can be reduced by about 33% and edges of the IR images become clearer.
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Tecnologia de Fibra Óptica/instrumentação , Aumento da Imagem/instrumentação , Fotometria/instrumentação , Termografia/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Raios InfravermelhosRESUMO
This paper presents a novel filtering method with a double triangular prism in an optical-readout thermal imaging system. First, the working principle of this system is described in detail, followed by the analysis of sensitivity. Then, infrared images of hands are obtained. On the basis of the analysis, it is concluded that this filtering method, whose noise equivalent temperature difference (NETD) can reach 145 mK, is effective in obtaining high-quality images. Finally, comparing the filtering method with a knife-edge filter, we can draw the conclusion that the filtering method can effectively improve image quality (the value of NETD is less than that of a knife-edge filter).
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AlN thin film is widely used in piezoelectric MEMS devices, and the accurate characterizations of its material coefficients are critical for the optimization of the AlN thin film process and the design of AlN thin-film-based devices. However, it is difficult to extract the material coefficients of AlN in the form of thin film. This paper reports a strategy for systematically extracting full elastic coefficients, piezoelectric coefficients and dielectric constants of c-axis-oriented AlN thin film based on the resonance method outlined in IEEE Standard on Piezoelectricity Std 176-1987. In this strategy, four self-suspended resonators with length thickness extension (LTE), thickness extension (TE), radial extension (RE), lateral electric field excited thickness shear (LEF-TS) modes together with a lamb wave resonator (LWR) are specifically adopted, and the material coefficients of AlN thin film are extracted by measuring the impedance spectra of these resonators. In addition, the effects of the pad and electrodes on the resonators were systematically studied, and the corresponding procedures to eliminate their influences on the extraction accuracy of material coefficients were proposed. Finally, a complete extraction process based on the above strategy was established. The simulation results show that the strategy can achieve high accuracy for AlN thin film with different thicknesses and electrode configurations, and it can also be applied to other materials belonging to the 6 mm piezoelectric crystal class such as ZnO, ScAlN, etc.
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The microfluidic device (MFD) with a glass−PDMS−glass (G-P-G) structure is of interest for a wide range of applications. However, G-P-G MFD fabrication with an ultra-thin PDMS film (especially thickness less than 200 µm) is still a big challenge because the ultra-thin PDMS film is easily deformed, curled, and damaged during demolding and transferring. This study aimed to report a thickness-controllable and low-cost fabrication process of the G-P-G MFD with an ultra-thin PDMS film based on a flexible mold peel-off process. A patterned photoresist layer was deposited on a polyethylene terephthalate (PET) film to fabricate a flexible mold that could be demolded softly to achieve a rigid structure of the glass−PDMS film. The thickness of ultra-thin patterned PDMS could reach less than 50 µm without damage to the PDMS film. The MFD showcased the excellent property of water evaporation inhibition (water loss < 10%) during PCR thermal cycling because of the ultra-thin PDMS film. Its low-cost fabrication process and excellent water evaporation inhibition present extremely high prospects for digital PCR application.
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OBJECTIVE: To explore the value of red blood cell distribution width (RDW) in evaluating the severity of patients infected with novel coronavirus Delta variant. METHODS: A total of 28 patients infected with novel coronavirus Delta variant in designated hospital treated by the First Affiliated Hospital of Xi'an Jiaotong University medical team from December 2021 to January 2022 were enrolled (23 cases of common type, 4 severe and 1 critical cases). The detailed clinical data of patients was collected. Then, Pearson's correlation analysis was used to identify the blood examination indexes which affected the arterial partial pressure of oxygen (PaO2) and arterial partial pressure of carbon dioxide (PaCO2). According to the median standard deviation of red blood cell distribution width (RDW-SD, 42.5 fL), 28 patients were divided into low RDW-SD group (≤ 42.5 fL, 16 cases) and high RDW-SD group (> 42.5 fL, 12 cases), and the immune related indexes of the two groups were compared. Receiver operator characteristic curve (ROC) was drawn to evaluate the predictive value of RDW-SD on the severity of illness of coronavirus disease 2019 (COVID-19). RESULTS: Correlation analysis showed that RDW-SD was the only index related to PaO2 and PaCO2 on the first day of admission, which was negative correlation with PaO2 (r = -0.379, P = 0.047) and positive correlation with PaCO2 (r = 0.509, P = 0.006). The results of effects of different clinical characteristics on RDW-SD level showed that there was no statistically significant difference in RDW-SD between groups with different clinical characteristics (including male/female, ≥ 65 years old/< 65 years old, having/without hypertension, having/without diabetes, smoking/not smoking, having/without hyperpyrexia, with/without fever for 3 days, with/without respiratory symptoms, with/without digestive symptoms). It was suggested that RDW-SD be relatively stable and not affected by the patient's baseline level. The percentage of B cells in low RDW-SD group was higher than that in high RDW-SD group (23.01±3.01 vs. 15.34±5.34, P < 0.05), immunoglobulin G (IgG) level in low RDW-SD group was lower than that in high RDW-SD group (g/L: 11.43±3.20 vs. 15.42±1.54, P < 0.05). The area under ROC curve (AUC) of RDW-SD in evaluating severe cases was 0.83 [95% confidence interval (95%CI) was 0.59-1.06], which was close to multilobularinltration, hypo-lymphocytosis, bacterial coinfection, smoking history, hyper-tension and age (MuL BSTA score; AUC = 0.82, 95%CI was 0.51-1.12) and better than British Thoracic Society's modified pneumonia score (CURB-65 score; AUC = 0.70, 95%CI was 0.50-0.91). CONCLUSIONS: RDW-SD has significant evaluative effect on the severity of COVID-19 patients with Delta variants.