A comprehensive overview on the transmission, pathogenesis, diagnosis, treatment, and prevention of SARS-CoV-2.

Severe acute respiratory syndrome coronavirus (SARS-CoV) is a single positive-strand RNA virus that is responsible for the current pandemic that the world has been facing since 2019. The primary route of transmission of SARS-CoV-2 is through respiratory tract transmission. However, other transmission routes such as fecal-oral, vertical transmission, and aerosol-eye also exist. In addition, it has been found that the pathogenesis of this virus involves the binding of the virus's S protein to its host cell surface receptor angiotensin-converting enzyme 2, which results in the subsequent membrane fusion that is required for SARS-CoV-2 to replicate and complete its entire life. The clinical symptoms of patients infected with SARS-CoV-2 can range from asymptomatic to severe. The most common symptoms seen include fever, dry cough, and fatigue. Once these symptoms are observed, a nucleic acid test is done using reverse transcription-polymerase chain reaction. This currently serves as the main confirmatory tool for COVID-19. Despite the fact that no cure has been found for SARS-CoV-2, prevention methods such as vaccines, specific facial mask, and social distancing have proven to be quite effective. It is imperative to have a complete understanding of the transmission and pathogenesis of this virus. To effectively develop new drugs as well as diagnostic tools, more knowledge about this virus would be needed.

Enhancing Strong-Field Dissociation of H_{2}

We investigate the above-threshold multiphoton ionization of H_{2} embedded in superfluid He nanodroplets driven by ultraviolet femtosecond laser pulses. We find that the surrounding He atoms enhance the dissociation of in-droplet H_{2}^{+} from lower vibrational states as compared to that of isolated gas-phase molecules. As a result, the discrete peaks in the photoelectron energy spectrum correlated with the HHe^{+} from the dissociative in-droplet molecule shift to higher energies. Based on the electron-nuclear correlation, the photoelectrons with higher energies are correlated to the nuclei of the low-vibrationally excited molecular ion as the nuclei share less photon energy. Our time-dependent nuclear wave packet quantum simulation using a simplified He-H_{2}^{+} system confirms the joint contribution of the driving laser field and the neighboring He atoms to the dissociation dynamics of the solute molecular ion. The results strengthen our understanding of the role of the environment on light-induced ultrafast dynamics of molecules.

Manipulating Parallel and Perpendicular Multiphoton Transitions in H_{2} Molecules.

We demonstrate that dissociative ionization of H_{2} can be fully manipulated in an angle-time-resolved fashion, employing a polarization-skewed (PS) laser pulse in which the polarization vector rotates. The leading and falling edges of the PS laser pulse, characterized by unfolded field polarization, trigger, sequentially, parallel and perpendicular transitions of stretching H_{2} molecules, respectively. These transitions result in counterintuitive proton ejections that deviate significantly from the laser polarization directions. Our findings demonstrate that the reaction pathways can be controlled through fine-tuning the time-dependent polarization of the PS laser pulse. The experimental results are well reproduced using an intuitive wave-packet surface propagation simulation method. This research highlights the potential of PS laser pulses as powerful tweezers to resolve and manipulate complex laser-molecule interactions.

Fatal, non-fatal burden of cancer in the elderly in China, 2005-2016: a nationwide registry-based study.

BACKGROUND: As populations age, cancer burden becomes increasingly conspicuous. This study quantified the cancer burden of the elderly (≥ 60 years) in China, based on the China Cancer Registry Annual Report to provide epidemiological evidence for cancer prevention and control. METHODS: Data on cancer cases and deaths among the elderly aged ≥ 60 years were collected from the China Cancer Registry Annual Report, 2008-2019. Potential years of life lost (PYLL) and disability-adjusted life years (DALY) were calculated to analyze fatalities and the non-fatal burden. The time trend was analyzed using the Joinpoint model. RESULTS: From 2005 to 2016, the PYLL rate of cancer in the elderly was stable between 45.34‰ and 47.62‰, but the DALY rate for cancer decreased at an average annual rate of 1.18% (95% CI: 0.84-1.52%). The non-fatal cancer burden in the rural elderly was higher than that of the urban elderly. Lung, gastric, liver, esophageal, and colorectal cancers were the main cancers causing the cancer burden in the elderly, and accounted for 74.3% of DALYs. The DALY rate of lung cancer in females in the 60-64 age group increased (annual percentage change [APC] = 1.14%, 95% CI: 0.10-1.82%). Female breast cancer was one of the top five cancers in the 60-64 age group, with DALY rates that also increased (APC = 2.17%, 95% CI: 1.35-3.01%). With increasing age, the burden of liver cancer decreased, while that of colorectal cancer rose. CONCLUSIONS: From 2005 to 2016, the cancer burden in the elderly in China decreased, mainly reflected in the non-fatal burden. Female breast and liver cancer were a more serious burden in the younger elderly, while colorectal cancer burden was mainly observed in the older elderly.

Magnetic-Field Effect as a Tool to Investigate Electron Correlation in Strong-Field Ionization.

The influence of the magnetic component of the driving electromagnetic field is often neglected when investigating light-matter interaction. We show that the magnetic component of the light field plays an important role in nonsequential double ionization, which serves as a powerful tool to investigate electron correlation. We investigate the magnetic-field effects in double ionization of xenon atoms driven by near-infrared ultrashort femtosecond laser pulses and find that the mean forward shift of the electron momentum distribution in light-propagation direction agrees well with the classical prediction, where no under-barrier or recollisional nondipole enhancement is observed. By extending classical trajectory Monte Carlo simulations beyond the dipole approximation, we reveal that double ionization proceeds via recollision-induced doubly excited states, followed by subsequent sequential over-barrier field ionization of the two electrons. In agreement with this model, the binding energies do not lead to an additional nondipole forward shift of the electrons. Our findings provide a new method to study electron correlation by exploiting the effect of the magnetic component of the electromagnetic field.

Femtosecond Rotational Dynamics of D_{2} Molecules in Superfluid Helium Nanodroplets.

Rotational dynamics of D_{2} molecules inside helium nanodroplets is induced by a moderately intense femtosecond pump pulse and measured as a function of time by recording the yield of HeD^{+} ions, created through strong-field dissociative ionization with a delayed femtosecond probe pulse. The yield oscillates with a period of 185 fs, reflecting field-free rotational wave packet dynamics, and the oscillation persists for more than 500 periods. Within the experimental uncertainty, the rotational constant B_{He} of the in-droplet D_{2} molecule, determined by Fourier analysis, is the same as B_{gas} for an isolated D_{2} molecule. Our observations show that the D_{2} molecules inside helium nanodroplets essentially rotate as free D_{2} molecules.

Magnetic-Field Effect in High-Order Above-Threshold Ionization.

We experimentally and theoretically investigate the influence of the magnetic component of an electromagnetic field on high-order above-threshold ionization of xenon atoms driven by ultrashort femtosecond laser pulses. The nondipole shift of the electron momentum distribution along the light-propagation direction for high energy electrons beyond the 2U_{p} classical cutoff is found to be vastly different from that below this cutoff, where U_{p} is the ponderomotive potential of the driving laser field. A local minimum structure in the momentum dependence of the nondipole shift above the cutoff is identified for the first time. With the help of classical and quantum-orbit analysis, we show that large-angle rescattering of the electrons strongly alters the partitioning of the photon momentum between electron and ion. The sensitivity of the observed nondipole shift to the electronic structure of the target atom is confirmed by three-dimensional time-dependent Schrödinger equation simulations for different model potentials. Our work paves the way toward understanding the physics of extreme light-matter interactions at long wavelengths and high electron kinetic energies.

A novel prognostic index of hepatocellular carcinoma based on immunogenomic landscape analysis.

Changes in immune responses to hepatocellular carcinoma (HCC) are closely related to the occurrence, development, and prognosis of this disease. Exploring the role of immune-related genes (IRGs) in HCC would provide insights into the mechanisms regulating this disease. The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) provide a platform for such research, owing to a large number of HCC samples available for comprehensive and systematic immunogenomics analyses. We analyzed the IRGs expression profile and clinical information of patients with HCC based on the TCGA and ICGC database. Potential molecular mechanisms and properties of the screened IRGs were analyzed across multiple databases. And we analyzed the correlation between IRGs, single-nucleotide polymorphisms, and copy number variation. A novel prognostic index, based on IRGs, was developed using the LASSO Cox regression algorithm, followed by univariate and multivariate Cox regression analyses to analyze the prognostic index. Information in the ICGC database was used to verify the reliability of the prognostic index. A total of 54 differentially expressed IRGs were found to be significantly associated with HCC prognosis, and there is a significant correlation between their expression level and copy number variation. Functional enrichment analyses indicated that the genes play active roles in tumor and immune-related signaling pathways. In addition, five potential biomarkers namely IRG, MAPK3, HSP90AA1, HSP90AB1, HSPA4, and CDK4, were identified. Finally, a novel prognostic index, based on IRGs (PSMD14, FABP6, ISG20L2, HGF, BIRC5, IL17D, and STC2), was found useful as an independent prognostic factor, not only for prognosis but also to reflect levels of infiltration in a variety of immune cells. Our team conducted a genomics study of IRGs in HCC and screened several clinically significant IRGs, and our model provides an effective approach for stratification and characterization of patients using IRG-based immunolabeling tools to monitor the prognosis of HCC.

Identification and functional analysis of the SARS-COV-2 nucleocapsid protein.

BACKGROUND: A severe form of pneumonia, named coronavirus disease 2019 (COVID-19) by the World Health Organization is widespread on the whole world. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was proved to be the main agent of COVID-19. In the present study, we conducted an in depth analysis of the SARS-COV-2 nucleocapsid to identify potential targets that may allow identification of therapeutic targets. METHODS: The SARS-COV-2 N protein subcellular localization and physicochemical property was analyzed by PSORT II Prediction and ProtParam tool. Then SOPMA tool and swiss-model was applied to analyze the structure of N protein. Next, the biological function was explored by mass spectrometry analysis and flow cytometry. At last, its potential phosphorylation sites were analyzed by NetPhos3.1 Server and PROVEAN PROTEIN. RESULTS: SARS-COV-2 N protein composed of 419 aa, is a 45.6 kDa positively charged unstable hydrophobic protein. It has 91 and 49% similarity to SARS-CoV and MERS-CoV and is predicted to be predominantly a nuclear protein. It mainly contains random coil (55.13%) of which the tertiary structure was further determined with high reliability (95.76%). Cells transfected with SARS-COV-2 N protein usually show a G1/S phase block company with an increased expression of TUBA1C, TUBB6. At last, our analysis of SARS-COV-2 N protein predicted a total number of 12 phosphorylated sites and 9 potential protein kinases which would significantly affect SARS-COV-2 N protein function. CONCLUSION: In this study, we report the physicochemical properties, subcellular localization, and biological function of SARS-COV-2 N protein. The 12 phosphorylated sites and 9 potential protein kinase sites in SARS-COV-2 N protein may serve as promising targets for drug discovery and development for of a recombinant virus vaccine.

Effect of infrahepatic inferior vena cava partial clamping on central venous pressure and intraoperative blood loss during laparoscopic hepatectomy.

BACKGROUND: Infrahepatic inferior vena cava (IVC) clamping is considered to be an effective method to reduce central venous pressure (CVP) and intraoperative bleeding in liver resection. However, its efficacy and safety during laparoscopic hepatectomy (LH) remain unclear. We perform this retrospective study to evaluate its efficacy and safety during LH. METHODS: Consecutive patients scheduled for LH from September 2014 to August 2019 were retrospectively reviewed. The intraoperative parameters and postoperative outcomes were analyzed. RESULTS: All patients in the infrahepatic IVC clamping group were able to tolerate partial clamping of IVC. The CVP was significantly decreased after infrahepatic IVC clamping without hemodynamic instability (8.7 ± 1.4 cmH2O vs. 2.1 ± 1.3 cmH2O, P = 0.000). Infrahepatic IVC clamping did not significantly reduce total blood loss (287.3 ± 112.5 mL vs. 301.4 ± 127.6 mL, P = 0.133) and blood loss during parenchymal transection (273.2 ± 107.9 mL vs. 296.5 ± 118.1 mL, P = 0.618) compared with the non-clamping group. In subgroup analysis, total blood loss and blood loss during parenchymal transection were significantly reduced in patients with moderate to severe cirrhosis in the clamping group (363.6 ± 71.2 mL vs. 473.4 ± 95.6 mL, P = 0.021), (358.7 ± 70.9 mL vs. 466.9 ± 94.5 mL, P = 0.016), respectively. The complications and hospital stay were comparable. CONCLUSIONS: In conclusion, these data suggest that infrahepatic IVC clamping may be safe and effective.

High-order above-threshold dissociation of molecules.

Electrons bound to atoms or molecules can simultaneously absorb multiple photons via the above-threshold ionization featured with discrete peaks in the photoelectron spectrum on account of the quantized nature of the light energy. Analogously, the above-threshold dissociation of molecules has been proposed to address the multiple-photon energy deposition in the nuclei of molecules. In this case, nuclear energy spectra consisting of photon-energy spaced peaks exceeding the binding energy of the molecular bond are predicted. Although the observation of such phenomena is difficult, this scenario is nevertheless logical and is based on the fundamental laws. Here, we report conclusive experimental observation of high-order above-threshold dissociation of H2 in strong laser fields where the tunneling-ionized electron transfers the absorbed multiphoton energy, which is above the ionization threshold to the nuclei via the field-driven inelastic rescattering. Our results provide an unambiguous evidence that the electron and nuclei of a molecule as a whole absorb multiple photons, and thus above-threshold ionization and above-threshold dissociation must appear simultaneously, which is the cornerstone of the nowadays strong-field molecular physics.

Effect Analysis of GNSS/INS Processing Strategy for Sufficient Utilization of Urban Environment Observations.

The occlusion of buildings in urban environments leads to the intermittent reception of satellite signals, which limits the utilization of observations. This subsequently results in a decline of the positioning and attitude accuracy of Global Navigation Satellite System (GNSS)/Inertial Navigation System (INS) integrated system (GNSS/INS). This study implements a smooth post-processing strategy based on a tightly coupled differential GNSS/INS. Specifically, this strategy used the INS-estimated position to reinitialize integer ambiguity. The GNSS raw observations were input into the Kalman filter to update the measurement. The Rauch-Tung-Striebel smoothing (RTSS) algorithm was used to process the observations of the entire period. This study analyzed the performance of loosely coupled and tightly coupled systems in an urban environment and the improvement of the RTSS algorithm on the navigation solution from the perspective of fully mining the observations. The experimental results of the simulation data and real data show that, compared with the traditional tightly coupled processing strategy which does not use INS-aided integer ambiguity resolution and RTSS algorithm, the strategy in this study sufficiently utilized INS observations and GNSS observations to effectively improve the accuracy of positioning and attitude and ensure the continuity of navigation results in an obstructed environment.

Prevalence and Risk Factors of Kaposi's Sarcoma-Associated Herpesvirus Infection among Han and Uygur Populations in Xinjiang, China.

Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma (KS), which is endangering human health worldwide, especially in Africa, Europe, the United States, and parts of Asia. The aim of this study was to investigate the prevalence of KSHV in Xinjiang. Three KSHV recombinant proteins (ORF65, ORF73, and K8.1) were used to detect KSHV infection. The serum samples to be tested were detected by an indirect ELISA method. The overall infection rate of KSHV in Xinjiang was 25.60%, with a higher infection rate in the Uygur population of 29.79%. After adjusting for possible confounders, Uygur (OR = 3.95, 95% CI 2.64-6.12, P < 0.001), agriculture and livestock (OR = 1.60, 95% CI 1.20-2.17, P = 0.002), age ≤ 50 years (OR = 1.50, 95% CI 1.13-2.00, P = 0.006), and predominantly meat-based diet (OR = 1.72, 95% CI 1.11-2.78, P = 0.018) were significantly associated with the odds of KSHV seropositivity correlation. Three unique sequences of KSHV were obtained in this study; genotypic analysis showed that the three unique sequences were all subtype A2.

LncRNA SATB2-AS1 inhibits tumor metastasis and affects the tumor immune cell microenvironment in colorectal cancer by regulating SATB2.

BACKGROUND: Emerging studies suggest that long non-coding RNAs (lncRNAs) play crucial roles in colorectal cancer (CRC). Here, we report a lncRNA, SATB2-AS1, which is specifically expressed in colorectal tissue and is significantly reduced in CRC. We systematically elucidated its functions and possible molecular mechanisms in CRC. METHODS: LncRNA expression in CRC was analyzed by RNA-sequencing and RNA microarrays. The expression level of SATB2-AS1 in tissues was determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH). The functional role of SATB2-AS1 in CRC was investigated by a series of in vivo and in vitro assays. RNA pull-down, RNA immunoprecipitation (RIP), chromatin immunoprecipitation (ChIP), chromatin isolation by RNA purification (ChIRP), Bisulfite Sequencing PCR (BSP) and bioinformatics analysis were utilized to explore the potential mechanisms of SATB2-AS1. RESULTS: SATB2-AS1 is specifically expressed in colorectal tissues and downregulated in CRC. Survival analysis indicates that decreased SATB2-AS1 expression is associated with poor survival. Functional experiments and bioinformatics analysis revealed that SATB2-AS1 inhibits CRC cell metastasis and regulates TH1-type chemokines expression and immune cell density in CRC. Mechanistically, SATB2-AS1 directly binds to WDR5 and GADD45A, cis-activating SATB2 (Special AT-rich binding protein 2) transcription via mediating histone H3 lysine 4 tri-methylation (H3K4me3) deposition and DNA demethylation of the promoter region of SATB2. CONCLUSIONS: This study reveals the functions of SATB2-AS1 in CRC tumorigenesis and progression, suggesting new biomarkers and therapeutic targets in CRC.

Timing Dissociative Ionization of H_{2} Using a Polarization-Skewed Femtosecond Laser Pulse.

We experimentally observe the bond stretching time of one-photon and net-two-photon dissociation pathways of singly ionized H_{2} molecules driven by a polarization-skewed femtosecond laser pulse. By measuring the angular distributions of the ejected photoelectron and nuclear fragments in coincidence, the cycle-changing polarization of the laser field enables us to clock the photon-ionization starting time and photon-dissociation stopping time, analogous to a stopwatch. After the single ionization of H_{2}, our results show that the produced H_{2}^{+} takes almost the same time in the one-photon and net-two-photon dissociation pathways to stretch to the internuclear distance of the one-photon coupled dipole-transition between the ground and excited electronic states. The spatiotemporal mapping character of the polarization-skewed laser field provides us a straightforward route to clock the ultrafast dynamics of molecules with sub-optical-cycle time resolution.

The long noncoding RNA SNHG1 regulates colorectal cancer cell growth through interactions with EZH2 and miR-154-5p.

BACKGROUND: Mounting evidence demonstrates that long noncoding RNAs (lncRNAs) have critical roles during the initiation and progression of cancers. In this study, we report that the small nucleolar RNA host gene 1 (SNHG1) is involved in colorectal cancer progression. METHODS: We analyzed RNA sequencing data to explore abnormally expressed lncRNAs in colorectal cancer. The effects of SNHG1 on colorectal cancer were investigated through in vitro and in vivo assays (i.e., CCK-8 assay, colony formation assay, flow cytometry assay, EdU assay, xenograft model, immunohistochemistry, and western blot). The mechanism of SNHG1 action was explored through bioinformatics, RNA fluorescence in situ hybridization, luciferase reporter assay, RNA pull-down assay, chromatin immunoprecipitation assay and RNA immunoprecipitation assay. RESULTS: Our analysis revealed that SNHG1 was upregulated in human colorectal cancer tissues, and high SNHG1 expression was associated with reduced patient survival. We also found that high SNHG1 expression was partly induced by SP1. Moreover, SNHG1 knockdown significantly repressed colorectal cancer cells growth both in vitro and in vivo. Mechanistic investigations demonstrated that SNHG1 could directly interact with Polycomb Repressive Complex 2 (PRC2) and modulate the histone methylation of promoter of Kruppel like factor 2 (KLF2) and Cyclin dependent kinase inhibitor 2B (CDKN2B) in the nucleus. In the cytoplasm, SNHG1 acted as a sponge for miR-154-5p, reducing its ability to repress Cyclin D2 (CCND2) expression. CONCLUSIONS: Taken together, the results of our studies illuminate how SNHG1 formed a regulatory network to confer an oncogenic function in colorectal cancer and suggest that SNHG1 may serve as a potential target for colorectal cancer diagnosis and treatment.

Web-Based Experience Sharing Platform on Medical Device Incidents for Clinical Engineers in Hospitals.

The aim of this study was to establish a web-based platform for exchanging medical device management and maintenance experiences to enhance the professional competency of clinical engineers (CEs), which ensures the quality of medical devices and increases patients' satisfaction with medical services. Medical devices play an essential role in diagnosis and disease management. CEs are responsible for providing functional medical devices that contribute worthwhile functions to a medical service to improve patients' health and safety. The purpose of the platform is to facilitate collection and sharing of medical device incidents experiences to improve CEs' capability. To provide useful and practical information for CEs, an event review committee, composed of experts with more than 20 years of clinical engineering experience who were recruited as reviewers, was established under the platform. Cases submitted to the platform were required to have comprehensive descriptions of the device and events. Each case was evaluated by at least two reviewers based on five evaluation indices: (1) severity, (2) breadth, (3) frequency, (4) insidiousness, and (5) correctness. After being reviewed, each final report was published on the platform to be shared with the event submitters and other members. The results show that 116 staffs from 32 different hospitals, registered to join this platform. From January 2015 to December 2016, 70 events were submitted with 56 reports. This study also assessed the platform's benefits for CEs. A total of 93 respondents completed a questionnaire survey: 93% of the CEs agreed that the information from the platform helped them do their job. The web-based platform has high value as an experience-sharing interface for medical devices. The CEs obtained extremely useful information from the platform for medical device management and their daily duties. This study provided an online training model with systematic methods to improve the quality and effectiveness of medical device management.

Orientation-dependent strong-field dissociative single ionization of CO.

The dissociative ionization of CO in orthogonally polarized femtosecond laser pulses are studied in a pump-probe scheme. The ionization of CO by the pump pulse and the dissociation of the created CO+ by the probe pulse can be fully disentangled by identifying the photoelectron momentum distributions. Different from the dissociative ionization by a single pulse in which the CO molecule mostly breaks along the field polarization, in this pump-probe strategy, the CO+ ion created from ionization by the pump pulse is favored to dissociate when it orients orthogonal to the polarization direction of the probe pulse. It is attributed to the laser-coupling of various electronic states of the molecular ion in the dissociation process, supported by the numerical simulation of a modeled time-dependent Schrödinger equation.

Rotated echoes of molecular alignment: fractional, high order and imaginary.

We report experimental observations of rotated echoes of alignment induced by a pair of time-delayed and polarization-skewed femtosecond laser pulses interacting with an ensemble of molecular rotors. Rotated fractional echoes, rotated high order echoes and rotated imaginary echoes are directly visualized by using the technique of coincident Coulomb explosion imaging. We show that the echo phenomenon not only exhibits temporal recurrences but also spatial rotations determined by the polarization of the time-delayed second pulse. The dynamics of echo formation is well described by the laser-induced filamentation in rotational phase space. The quantum-mechanical simulation shows good agreements with the experimental results.

Energy-Resolved Ultrashort Delays of Photoelectron Emission Clocked by Orthogonal Two-Color Laser Fields.

A phase-controlled orthogonal two-color (OTC) femtosecond laser pulse is employed to probe the time delay of photoelectron emission in the strong-field ionization of atoms. The OTC field spatiotemporally steers the emission dynamics of the photoelectrons and meanwhile allows us to unambiguously distinguish the main and sideband peaks of the above-threshold ionization spectrum. The relative phase shift between the main and sideband peaks, retrieved from the phase-of-phase of the photoelectron spectrum as a function of the laser phase, gradually decreases with increasing electron energy, and becomes zero for the fast electron which is mainly produced by the rescattering process. Furthermore, a Freeman resonance delay of 140±40 attoseconds between photoelectrons emitted via the 4f and 5p Rydberg states of argon is observed.