Strategies to overcome the challenges of low or no expression of heterologous proteins in Escherichia coli.

Protein expression is a critical process in diverse biological systems. For Escherichia coli, a widely employed microbial host in industrial catalysis and healthcare, researchers often face significant challenges in constructing recombinant expression systems. To maximize the potential of E. coli expression systems, it is essential to address problems regarding the low or absent production of certain target proteins. This article presents viable solutions to the main factors posing challenges to heterologous protein expression in E. coli, which includes protein toxicity, the intrinsic influence of gene sequences, and mRNA structure. These strategies include specialized approaches for managing toxic protein expression, addressing issues related to mRNA structure and codon bias, advanced codon optimization methodologies that consider multiple factors, and emerging optimization techniques facilitated by big data and machine learning.

Self-assembly of nanocrystal checkerboard patterns via non-specific interactions.

Checkerboard lattices-where the resulting structure is open, porous, and highly symmetric-are difficult to create by self-assembly. Synthetic systems that adopt such structures typically rely on shape complementarity and site-specific chemical interactions that are only available to biomolecular systems (e.g., protein, DNA). Here we show the assembly of checkerboard lattices from colloidal nanocrystals that harness the effects of multiple, coupled physical forces at disparate length scales (interfacial, interparticle, and intermolecular) and that do not rely on chemical binding. Colloidal Ag nanocubes were bi-functionalized with mixtures of hydrophilic and hydrophobic surface ligands and subsequently assembled at an air-water interface. Using feedback between molecular dynamics simulations and interfacial assembly experiments, we achieve a periodic checkerboard mesostructure that represents a tiny fraction of the phase space associated with the polymer-grafted nanocrystals used in these experiments. In a broader context, this work expands our knowledge of non-specific nanocrystal interactions and presents a computation-guided strategy for designing self-assembling materials.

RNA damage compartmentalization by DHX9 stress granules.

Biomolecules incur damage during stress conditions, and damage partitioning represents a vital survival strategy for cells. Here, we identified a distinct stress granule (SG), marked by dsRNA helicase DHX9, which compartmentalizes ultraviolet (UV)-induced RNA, but not DNA, damage. Our FANCI technology revealed that DHX9 SGs are enriched in damaged intron RNA, in contrast to classical SGs that are composed of mature mRNA. UV exposure causes RNA crosslinking damage, impedes intron splicing and decay, and triggers DHX9 SGs within daughter cells. DHX9 SGs promote cell survival and induce dsRNA-related immune response and translation shutdown, differentiating them from classical SGs that assemble downstream of translation arrest. DHX9 modulates dsRNA abundance in the DHX9 SGs and promotes cell viability. Autophagy receptor p62 is activated and important for DHX9 SG disassembly. Our findings establish non-canonical DHX9 SGs as a dedicated non-membrane-bound cytoplasmic compartment that safeguards daughter cells from parental RNA damage.

Insight into the High Mobility and Stability of In2 O3 :H Film.

Wide bandgap semiconductors, particularly In2 O3 :Sn (ITO), are widely used as transparent conductive electrodes in optoelectronic devices. Nevertheless, due to the strohave beenng scattering probability of high-concentration oxygen vacancy (VO ) defects, the mobility of ITO is always lower than 40 cm2  V-1  s-1 . Recently, hydrogen-doped In2 O3 (In2 O3 :H) films have been proven to have high mobility (>100 cm2  V-1  s-1 ), but the origin of this high mobility is still unclear. Herein, a high-resolution electron microscope and theoretical calculations are employed to investigate the atomic-scale mechanisms behind the high carrier mobility in In2 O3 :H films. It is found that VO can cause strong lattice distortion and large carrier scattering probability, resulting in low carrier mobility. Furthermore, hydrogen doping can simultaneously reduce the concentration of VO , which accounts for high carrier mobility. The thermal stability and acid-base corrosion mechanism of the In2 O3 :H film are investigated and found that hydrogen overflows from the film at high temperatures (>250 °C), while acidic or alkaline environments can cause damage to the In2 O3 grains themselves. Overall, this work provides insights into the essential reasons for high carrier mobility in In2 O3 :H and presents a new research approach to the doping and stability mechanisms of transparent conductive oxides.

Factors influencing nasal airway pressure and comfort in high-flow nasal cannula oxygen therapy: a volunteer study.

BACKGROUND: High-flow nasal cannula (HFNC) oxygen therapy is essentially a constant-flow, noninvasive respiratory support system similar to a noninvasive ventilator operating in constant-flow mode. The clinical outcome of HFNC oxygen therapy is strongly associated with the pressure generated by high-flow gas and the patient's comfort level. This study was performed to explore the relevant factors affecting pressure and comfort of HFNC oxygen therapy in vivo. METHODS: Thirty-five healthy volunteers were enrolled in the trial. They underwent placement of nasal cannulas of various inner diameters (3, 4 or 5 mm) and treatment with different HFNC devices [HFT-300 (Weishengkang Medical Technology Co., Ltd., Jiangsu China) or H-80 M (BMC Medical Co., Ltd., Beijing China)],and the nasal airway pressure and comfort were assessed. Multiple linear regression was used to determine predictors of airway pressure. RESULTS: Multiple linear regression showed that the end-expiratory pressure was associated with the flow rate, sex, height, and cannula size. The end-expiratory pressure increased by 0.6 cmH2O per 1-mm increase in cannula diameter, decreased by 0.3 cmH2O per 10-cm increase in participant height (with a 0.35 cmH2O decrease for men), and increased by 1 cmH2O when the flow rate increased by 10 L/min (R2 = 0.75, P < 0.05 for all variables in model). In addition, the pressure generated by the H-80 M device was higher than that generated by the HFT-300 device (P < 0.05). Discomfort manifested as difficulty in expiration, and its severity increased as the cannula diameter increased; however there was no significant difference in comfort between the two HFNC devices (P > 0.05). CONCLUSION: In volunteers undergoing HFNC oxygen therapy, the nasal cannula diameter, flow rate, sex, height, and device model can affect the nasal airway pressure, and the nasal catheter diameter and flow rate can affect comfort. These factors should be given close attention in clinical practice. TRIAL REGISTRATION: ChiCTR2300068313 (date of first registration: 14 February 2023,  https://www.chictr.org.cn ).

Congenital second branchial cleft anomalies in children: A report of 52 surgical cases, with emphasis on characteristic CT findings.

Objective: The objectives of this study was to review the clinical features and surgical treatment outcomes of congenital second branchial cleft anomalies (CSBCAs) and to investigate the characteristic computed tomography (CT) findings of CSBCAs. Methods: We conducted a retrospective study of 52 children who were referred to Shanghai Children's Hospital from October 2014 to December 2021 diagnosed as CSBCAs. Results: There were 36 males and 16 females. Of them, 35 patients were presented as having a skin pit at birth or discharge from the skin opening on the lateral neck, and 17 patients presented with an asymptomatic or painful mass. The typical CT features of CSBCAs included isolated and homogeneously hypodense cystic lesions surrounded by a uniformly thin, smooth wall. CSBCAs were generally located at the anteromedial border of the sternocleidomastoid muscle, posterior to the submandibular gland, and lateral to the carotid sheath. All patients were treated surgically and only one case underwent ipsilateral tonsillectomy. After a median follow-up of 30 (range 4-90) months, no recurrence or complications were observed. Conclusions: The CSBCAs show some characteristic CT findings, which can help clinicians diagnose and plan surgical strategies. High ligation of the lesions is sufficient for complete excision of CSBCAs.

Infection rate and factors affecting close contacts of COVID-19 cases: A systematic review.

OBJECTIVE: Contact tracing plays an essential role in mitigating the impact of an epidemic. During the COVID-19 pandemic, studies of those who have been in close contact with confirmed cases offer critical insights to understand the epidemiological characteristics of SARS-CoV-2 better. This study conducts a meta-analysis of existing studies' infection rates and affecting factors. METHODS: We searched PubMed, Web of Science and CNKI from the inception to April 30 2022 to identify systematic reviews. Two reviewers independently extracted the data and assessed risk of bias. Meta-analyses were conducted to calculate pooled estimates by using Stata/SE 15.1 software. RESULTS: There were 47 studies in the meta-analysis. Among COVID-19 close contacts, older age (RR = 1.94, 95% CI: 1.70, 2.21), contacts in households (RR = 2.83, 95% CI: 2.20, 3.65), and people in close contact with symptomatic infections (RR = 3.62, 95% CI: 1.88, 6.96) were associated with higher infection rates. CONCLUSION: On average, each primary infection corresponded to 5.8 close contacts. Among COVID-19 close contacts, older age and contacts in households were associated with higher infection rates, and people in close contact with symptomatic infections had three times higher risk of infection compared to people in close contact with asymptomatic infections. In general, there are significantly more studies from China about close contacts, and the infection rate among close contacts was lower compared to other countries.

Discovery of two-dimensional binary nanoparticle superlattices using global Monte Carlo optimization.

Binary nanoparticle (NP) superlattices exhibit distinct collective plasmonic, magnetic, optical, and electronic properties. Here, we computationally demonstrate how fluid-fluid interfaces could be used to self-assemble binary systems of NPs into 2D superlattices when the NP species exhibit different miscibility with the fluids forming the interface. We develop a basin-hopping Monte Carlo (BHMC) algorithm tailored for interface-trapped structures to rapidly determine the ground-state configuration of NPs, allowing us to explore the repertoire of binary NP architectures formed at the interface. By varying the NP size ratio, interparticle interaction strength, and difference in NP miscibility with the two fluids, we demonstrate the assembly of an array of exquisite 2D periodic architectures, including AB-, AB2-, and AB3-type monolayer superlattices as well as AB-, AB2-, A3B5-, and A4B6-type bilayer superlattices. Our results suggest that the interfacial assembly approach could be a versatile platform for fabricating 2D colloidal superlattices with tunable structure and properties.

[Preliminary study on efficacy and safety of submucosal plasma ablation of inferior turbinate in children with allergic rhinitis complicated with obstructive sleep apnea syndrome].

Objective:This study aimed to investigate the long-term clinical efficacy and safety of inferior turbinate submucosal plasma ablation combined with or without tonsillar and adenoid surgery in children with allergic rhinitis（AR） combined with obstructive sleep apnea syndrome（OSAS） who were ineffective after conservative systemic treatment. Methods:A total of 43 children with AR complicated with OSAS who met the inclusion criteria among 68 children hospitalized from January 2019 to February 2022 were retrospectively analyzed. The data were collected, including the clinical characteristics, surgical methods perioperative management and prevention and treatment of complications. Moreover, one year follow-up was performed to compare the VAS scores of children before and after surgery, and to evaluate their mid-term and long-term outcomes. Results:The average operation time was 36 minutes, meanwhile, the intraoperative blood was limited. The symptoms of nasal congestion, runny nose, sleep snoring, and mouth breathing were significantly improved after operation, and the results were satisfactory after one-year follow-up without complications such as bleeding, hematoma, intraoperative adhesion, and nasal dryness. Conclusion:Submucosal plasma ablation of inferior turbinate with or without tonsillectomy adenoidectomy in children with AR can effectively improve the clinical symptoms of AR combined with OSAS children who are ineffective after conservative treatment. It can improve the symptoms of sleep-disordered breathing such as sleep snoring and mouth breathing, with good mid-and long-term curative effects and fewer complications, which is an effective and safe treatment for children with AR combined with OSAS.

Influence of Polymer Characteristics on the Self-Assembly of Polymer-Grafted Metal-Organic Framework Particles.

Polymer-grafted metal-organic frameworks (MOFs) can combine the properties of MOFs and polymers into a single, matrix-free composite material. Herein, we examine polymer-grafted MOF particles (using UiO-66 as a model system) to examine how the molecular weight, grafting density, and chemical functionality of the polymer graft affects the preparation of free-standing self-assembled MOF monolayers (SAMMs). The physical properties of the monolayers are influenced by the choice of polymer, and robust, flexible monolayers were achieved more readily with poly(methyl acrylate) when compared to poly(methyl methacrylate) or poly(benzyl methacrylate). Molecular dynamics simulations were carried out to provide insights into the orientation and ordering of MOFs in the monolayers with respect to MOF size, graft length, and hydrophobicity. The relationship between molecular weight and graft density of the polymer brush was investigated and related to polymer brush conformation, offering design rules for further optimizations to balance mechanical strength, MOF weight fraction, and processability for this class of hybrid materials.

Controllable fabrication of hollow In2O3 nanoparticles by electron beam irradiation.

A growth strategy is presented for controllable fabrication of hollow In2O3 nanoparticles (NPs) via oxidation of In nanocrystals under electron beam irradiation. The morphology of the NPs can be tailored by changing the electron beam energy and current density. Yolk-shell NPs are preferentially formed under 200 keV electron beam irradiation, while hollow NPs are preferentially formed at 300 keV. This work confirms that electron beam irradiation is a valuable method for the engineering and modification of nanomaterials.

Involvement of microRNAs and their potential diagnostic, therapeutic, and prognostic role in hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) accounts for 85%-90% of primary liver cancer. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression by targeting the 3'UTR of mRNA. Abnormal expression and regulation of miRNAs are involved in the occurrence and progression of HCC, and miRNAs can also play a role in the diagnosis and treatment of HCC as oncogenes or tumor suppressors. METHODS: In the past decades, a large number of studies have shown that miRNAs play an essential regulatory role in HCC and have potential as biomarkers for HCC. We reviewed the literature to summarize these studies. RESULTS: By reviewing the literature, we retrospected the roles of miRNAs in the development, diagnosis, treatment, and prognosis of HCC, and put forward prospects for the further research on miRNAs in the precision treatment of HCC. CONCLUSION: MicroRNAs are important regulators and biomarkers in the occurrence, progression, outcome, and treatment of HCC, and can provide new targets and strategies for improving the therapeutic effect of HCC.

[Study on CT features of congenital branchial cleft anomaly in children].

Objective:To summarize the CT features of congenital branchial cleft anomaly in children, to reduce misdiagnosis and improve surgical strategy. Methods:This study enrolled 323 pediatric patients with congenital first branchial cleft anomaly, congenital second branchial cleft anomaly and congenital piriform sinus fistula confirmed by surgery and post-operative histopathology, who was admitted to Shanghai Children's hospital from August 2014 to January 2021., CT imaging data were retrospectively analyzed. Results:A total of 323 children with congenital branchial cleft deformity were included. There were 145 males and 178 females, aged from 22 days to 15 years. 119（119/323, 36.8%） cases were diagnosed as congenital first branchial cleft anomaly. Among them, 96 cases（96/119, 80.67%） were related to the wall of external auditory canal, and 89 cases（89/119, 74.78%） were related to parotid gland. The positive rate of CT examination was 87.4%（104/119）. 57 cases（57 / 323, 17.6%） had congenital second branchial cleft anomaly. Among them, 46 cases（46/57, 80.7%） were related to submandibular gland. The positive rate of CT examination was 84.2%（48/57）. 147 cases（147/323, 45.5%） had congenital piriform sinus fistula, in which 129 cases（129/147, 87.8%） were related to thyroid. The positive rate of CT was 89.1%（131/147）. Conclusion:The CT findings of congenital first branchial cleft anomaly are characterized by lesions in the inferior and/or posterior wall of ipsilateral external auditory canal and parotid gland. The CT features of congenital second branchial cleft anomaly are that the lesion is located on the ipsilateral submandibular gland （posterior and medial）. The CT features of congenital piriform sinus fistula are that the focus is located on the dorsal side of the upper pole of the lateral lobe of the thyroid gland.

Tunable Orientation and Assembly of Polymer-Grafted Nanocubes at Fluid-Fluid Interfaces.

Self-assembly of faceted nanoparticles is a promising route for fabricating nanomaterials; however, achieving low-dimensional assemblies of particles with tunable orientations is challenging. Here, we demonstrate that trapping surface-functionalized faceted nanoparticles at fluid-fluid interfaces is a viable approach for controlling particle orientation and facilitating their assembly into unique one- and two-dimensional superstructures. Using molecular dynamics simulations of polymer-grafted nanocubes in a polymer bilayer along with a particle-orientation classification method we developed, we show that the nanocubes can be induced into face-up, edge-up, or vertex-up orientations by tuning the graft density and differences in their miscibility with the two polymer layers. The orientational preference of the nanocubes is found to be governed by an interplay between the interfacial area occluded by the particle, the difference in interactions of the grafts with the two layers, and the stretching and intercalation of grafts at the interface. The resulting orientationally constrained nanocubes are then shown to assemble into a variety of unusual architectures, such as rectilinear strings, close-packed sheets, bilayer ribbons, and perforated sheets, which are difficult to obtain using other assembly methods. Our work thus demonstrates a versatile strategy for assembling freestanding arrays of faceted nanoparticles with possible applications in plasmonics, optics, catalysis, and membranes, where precise control over particle orientation and position is required.

Cytoplasmic PARP1 links the genome instability to the inhibition of antiviral immunity through PARylating cGAS.

Virus infection modulates both host immunity and host genomic stability. Poly(ADP-ribose) polymerase 1 (PARP1) is a key nuclear sensor of DNA damage, which maintains genomic integrity, and the successful application of PARP1 inhibitors for clinical anti-cancer therapy has lasted for decades. However, precisely how PARP1 gains access to cytoplasm and regulates antiviral immunity remains unknown. Here, we report that DNA virus induces a reactive nitrogen species (RNS)-dependent DNA damage and activates DNA-dependent protein kinase (DNA-PK). Activated DNA-PK phosphorylates PARP1 on Thr594, thus facilitating the cytoplasmic translocation of PARP1 to inhibit the antiviral immunity both in vitro and in vivo. Mechanistically, cytoplasmic PARP1 interacts with and directly PARylates cyclic GMP-AMP synthase (cGAS) on Asp191 to inhibit its DNA-binding ability. Together, our findings uncover an essential role of PARP1 in linking virus-induced genome instability with inhibition of host immunity, which is of relevance to cancer, autoinflammation, and other diseases.

Revealing the Phase Segregation and Evolution Dynamics in Binary Nanoalloys via Electron Beam-Assisted Ultrafast Heating and Cooling.

Gas-phase synthesized binary nanoparticles (NPs) possess ultraclean surfaces, which benefit versatile uses in sensors and catalysts. However, precise control of their configuration and properties is still a big challenge because the growth mechanism and phase evolution dynamics in these NPs are very hard to unveil. Here, we report a strategy to investigate the phase evolution dynamics in binary NPs by using e-beam assisted ultrafast local heating and cooling inside a transmission electron microscope. With this strategy, the phase segregation and corresponding shape evolution of PbBi NPs are in situ revealed. It is found that the as-prepared PbBi alloy NPs will transform into heterostructures under e-beam stimulated structural relaxation, leading to the formation of featured Janus configurations with faceted Bi polyhedron parts and intermetallic hemisphere parts. During phase segregation, Pb1Bi1 and Pb7Bi3 phases are captured and identified, and a model of phase and shape evolution of PbBi nanoalloys is developed and contrasted with that of their bulk counterparts. These findings benefit the understanding of the phase dynamics of binary NPs and can provide in-depth information for engineering their structures for practical applications.

Analysis of behavioral problems in children with sleep-disordered breathing and decreased REM sleep.

OBJECTIVE: REM sleep is known to be closely associated with behavioral problems in children. Our previous study showed that children with decreased REM sleep (REM < 10%) suffered from severe sleep-disordered breathing (SDB). In this study we explored the characteristics of behavioral problems in children with SDB and decreased REM sleep. METHODS: A total of 223 children were enrolled in the study. Sleep was evaluated by Polysomnography (PSG). Behavioral problems were assessed by a Chinese version of Child Behavior Checklist (parent-reported). Parameters of SDB and behavioral problem scores (internalizing, externalizing, and total scores) were compared between the children with decreased REM (REM < 10%) and those with REM ≥ 10% before and after controlling overweight/obesity and obstructive sleep apnea hypopnea syndrome (OSAHS). Parameters of SDB were also compared between the normal behavior group and the abnormal behavior group. The correlation between the behavioral problems and the sleep parameters was analyzed. RESULTS: The children with decreased REM sleep (<10%) had more severe externalizing and total behavioral problems, even when controlled for overweight/obesity. The abnormal behavior group had significantly shorter total sleep time and REM sleep compared to the normal behavior group. CONCLUSION: Children with SDB and decreased REM sleep showed more severe behavioral problems, especially the externalizing behavioral problems. The behavioral problems can be aggravated by insufficient total sleep. Decreased REM sleep in children may be an independent parameter that is associated with the behavioral problems in children with SDB.

Sub-4 nm Nanodiamonds from Graphene-Oxide and Nitrated Polycyclic Aromatic Hydrocarbons at 423 K.

Nanodiamonds are interesting materials from the point of view of their biocompatibility and their chemical, spectroscopic, and mechanical properties. Current synthetic methods for nanodiamonds involve harsh environments, which are potentially hazardous in addition to being expensive. We report a low-temperature (423 K) hydrothermal approach to form nanodiamonds by using graphene-oxide or nitrated polycyclic aromatic hydrocarbons (naphthalene, anthracene, phenanthrene, or pyrene) as a starting material. The reaction products contain single-crystalline or twinned nanodiamonds with average diameters in the 2-3 nm range. Theoretical calculations prove that, at the nanoscale, sub-4 nm nanodiamonds may adopt a structure that is more stable than graphene-oxide and nitrated polycyclic aromatic hydrocarbons. Our findings show that sp2 carbon in the polycyclic aromatic precursor can be converted to sp3 carbon under unexpectedly moderate temperature conditions by using nanoscale precursors and thus offer a low-temperature approach for the synthesis of sub-4 nm nanodiamonds.

Changes and significance of Treg and Th17 in adult patients with primary membranous nephropathy.

OBJECTIVE: To investigate the changes in Treg and Th17 cells and explore the significance of Treg/Th17 balance in adult primary membranous nephropathy (PMN) patients. MATERIALS AND METHODS: A total of 60 PMN patients and 50 healthy adults from June 2013 to October 2016 were enrolled in this study. The levels of Treg, Th17, and related cytokines were assessed. Pearson correlation was used for conducting correlation analysis. RESULTS: There was a significant increase in Th17 frequencies and IL-17 (Th17-related cytokines) in the peripheral blood mononuclear cells (PBMCs), as well as a significant decrease in Treg frequencies and IL-10 (Treg-related cytokines). The IL-17 concentrations in the peripheral blood of PMN patients were positively correlated with urinary protein, while IL-10 levels were negatively correlated with urinary protein. Protein expression of Treg transcription factor (Foxp3) was significantly low in the renal tissues of PMN patients, while the expression of IL-17 was much higher. Th17/Treg imbalance was reversed to normal after effective treatment with tacrolimus in 15 PMN patients. CONCLUSION: These results suggested the existence of Treg/Th17 imbalance in PMN patients, showing the importance of Treg/Th17 imbalance in PMN pathogenesis.

Liposomal clodronate combined with Cisplatin or Sorafenib inhibits hepatocellular carcinoma cell proliferation, migration and invasion by suppressing FOXQ1 expression.

The purpose of this study was to investigate the effect of liposomal clodronate combined with Cisplatin or Sorafenib on the FOXQ1 expression and biological function of hepatocellular carcinoma cell lines.  The expression of FOXQ1 was determined in normal hepatic cell line and hepatocellular carcinoma cell lines using quantitative real-time polymerase chain reaction (qRT-PCR). HepG2 and MHCC97H cells were administered low, medium and high concentrations of cisplatin (3, 5 and 7 µg/ml) or Sorafenib (2, 7 and 20 µg/ml) in combination with liposomal clodronate (LC, 20µg/ml), and the expression of FOXQ1 in each group was determined. Cell migration, MTT and transwell assays were used to determine the effects of the treatments on biological functions of HepG2 and MHCC97H cells. qRT-PCR showed that the expression of FOXQ1 mRNA was higher in the four hepatocellular carcinoma cell lines than in normal cells, and the expression of FOXQ1 mRNA in HepG2 and MHCC97H cells were more dominant. All the tested doses of Cisplatin, but only high dose Sorafenib down-regulated the expression of FOXQ1. However, Sorafenib at low and medium concentrations had no significant effect on the expression of FOXQ1. When Cisplatin or Sorafenib was administered in combination with LC, the expression level of FOXQ1 was significantly reduced. Cell migration, MTT and transwell assays showed that proliferation, migration and invasion were inhibited when each drug was administered alone, but was stronger when the drugs were combined with liposomal clodronate.Liposomal clodronate combined with Cisplatin or Sorafenib down-regulates the expression of FOXQ1 in HepG2 and MHCC97H hepatoma cells, and inhibits their proliferation, migration and invasion.