Aligned grains and scattered light found in gaps of planet-forming disk.

Polarized (sub)millimetre emission from dust grains in circumstellar disks was initially thought to be because of grains aligned with the magnetic field1,2. However, higher-resolution multi-wavelength observations3-5 and improved models6-10 found that this polarization is dominated by self-scattering at shorter wavelengths (for example, 870 µm) and by grains aligned with something other than magnetic fields at longer wavelengths (for example, 3 mm). Nevertheless, the polarization signal is expected to depend on the underlying substructure11-13, and observations until now have been unable to resolve polarization in multiple rings and gaps. HL Tau, a protoplanetary disk located 147.3 ± 0.5 pc away14, is the brightest class I or class II disk at millimetre-submillimetre wavelengths. Here we show deep, high-resolution polarization observations of HL Tau at 870 µm, resolving polarization in both the rings and the gaps. We find that the gaps have polarization angles with a notable azimuthal component and a higher polarization fraction than the rings. Our models show that the disk polarization is due to both scattering and emission from the aligned effectively prolate grains. The intrinsic polarization of aligned dust grains is probably more than 10%, which is much higher than that expected in low-resolution observations (about 1%). Asymmetries and dust features that are not seen in non-polarimetric observations are seen in the polarization observations.

Four annular structures in a protostellar disk less than 500,000 years old.

Annular structures (rings and gaps) in disks around pre-main-sequence stars have been detected in abundance towards class II protostellar objects that are approximately 1,000,000 years old1. These structures are often interpreted as evidence of planet formation1-3, with planetary-mass bodies carving rings and gaps in the disk4. This implies that planet formation may already be underway in even younger disks in the class I phase, when the protostar is still embedded in a larger-scale dense envelope of gas and dust5. Only within the past decade have detailed properties of disks in the earliest star-forming phases been observed6,7. Here we report 1.3-millimetre dust emission observations with a resolution of five astronomical units that show four annular substructures in the disk of the young (less than 500,000 years old)8 protostar IRS 63. IRS 63 is a single class I source located in the nearby Ophiuchus molecular cloud at a distance of 144 parsecs9, and is one of the brightest class I protostars at millimetre wavelengths. IRS 63 also has a relatively large disk compared to other young disks (greater than 50 astronomical units)10. Multiple annular substructures observed towards disks at young ages can act as an early foothold for dust-grain growth, which is a prerequisite of planet formation. Whether or not planets already exist in the disk of IRS 63, it is clear that the planet-formation process begins in the initial protostellar phases, earlier than predicted by current planet-formation theories11.

Improving both performance and stability of n-type organic semiconductors by vitamin C.

Organic semiconductors (OSCs) are one of the most promising candidates for flexible, wearable and large-area electronics. However, the development of n-type OSCs has been severely held back due to the poor stability of their most candidates, that is, the intrinsically high reactivity of negatively charged polarons to oxygen and water. Here we demonstrate a general strategy based on vitamin C to stabilize n-type OSCs, remarkably improving the performance and stability of their device, for example, organic field-effect transistors. Vitamin C scavenges reactive oxygen species and inhibits their generation by sacrificial oxidation and non-sacrificial triplet quenching in a cascade process, which not only lastingly prevents molecular structure from oxidation damage but also passivates the latent electron traps to stabilize electron transport. This study presents a way to overcome the long-standing stability problem of n-type OSCs and devices.

A study of the effect of number of children on depression among rural older women: empirical evidence from China.

The association between early reproductive events and health status in later life has always been of interest across disciplines. The purpose of this study was to investigate whether there was an association between the number of children born in the early years of elderly women and their depression in later life based on a sample of older women aged 65 years and above with at least one child in rural China. Data from the Chinese Longitudinal Healthy Longevity Survey in 2018, this study used the ordinary least square method to conduct empirical research. This study has found a significant correlation between an increase in the number of children and depression in older rural women. When considering the sex of the child, the number of daughters had a greater and more significant impact on depression. Number of children may exacerbate depression of older women through declining self-rated health and reduced social activity, while increased inter-generational support alleviated depression. The association between number of children born and depression also existed in urban older women, though not significant. Therefore, it is suggested to accelerate the improvement of supporting policies related to childbirth, developing a healthy and scientific fertility culture, and improving rural maternal and child health services. Women should be assisted in balancing their roles in the family and in society, and in particular in sharing the burden of caring for children. Targeted efforts to increase old-age protection for older people.

A Chemo-Enzymatic Approach for Preparing Efinaconazole with High Optical Yield.

Herein, we present a novel and ecofriendly biocatalytic approach for synthesizing efinaconazole (7), a clinically used antifungal agent. This method involves utilizing benzaldehyde lyase (BAL) to catalyze the crucial benzoin condensation step in the ketone precursor. Treating 2,4-difluorobenzaldehyde with BAL in the presence of thiamin-diphosphate (ThDP) and Mg2+ resulted in the formation of α-hydroxy ketone which then underwent the preparation of 7. This innovative approach not only provides a greener alternative but also offers significant advantages over the traditional chemical process. Through our efforts and development work, we have established efficient and scalable procedures that enable the production of 7 in a moderate 38% yield.

Thermal-Induced Performance Decay of the State-of-the-Art Polymer: Non-Fullerene Solar Cells and the Method of Suppression.

Improving thermal stability is of great importance for the industrialization of polymer solar cells (PSC). In this paper, we systematically investigated the high-temperature thermal annealing effect on the device performance of the state-of-the-art polymer:non-fullerene (PM6:Y6) solar cells with an inverted structure. Results revealed that the overall performance decay (19% decrease) was mainly due to the fast open-circuit voltage (VOC, 10% decrease) and fill factor (FF, 10% decrease) decays whereas short circuit current (JSC) was relatively stable upon annealing at 150 °C (0.5% decrease). Pre-annealing on the ZnO/PM6:Y6 at 150 °C before the completion of cell fabrication resulted in a 1.7% performance decrease, while annealing on the ZnO/PM6:Y6/MoO3 films led to a 10.5% performance decay, indicating that the degradation at the PM6:Y6/MoO3 interface is the main reason for the overall performance decay. The increased ideality factor and reduced built-in potential confirmed by dark J - V curve analysis further confirmed the increased interfacial charge recombination after thermal annealing. The interaction of PM6:Y6 and MoO3 was proved by UV-Vis absorption and XPS measurements. Such deep chemical doping of PM6:Y6 led to unfavorable band alignment at the interface, which led to increased surface charge recombination and reduced built-in potential of the cells after thermal annealing. Inserting a thin C60 layer between the PM6:Y6 and MoO3 significantly improved the cells' thermal stability, and less than 2% decay was measured for the optimized cell with 3 nm C60.

Practical Prelithiation of 4.5 V LiCoO2 ||Graphite Batteries by a Passivated Lithium-Carbon Composite.

Prelithiation can replenish active Li into the battery to compensate the Li consumption due to the formation of solid electrolyte interphase (SEI) on the electrode surface, therefore improving the energy density of Li-ion batteries (LIBs), especially for batteries using electrode materials with low initial Coulombic efficiency (ICE). However, practical prelithiation in LIBs is a challenge since most lithiated compounds with high specific capacity are unstable and industrially incompatible. Herein, an effective prelithiation strategy is demonstrated by using a lithium-carbon (Li-C) microsphere composite. These Li-C microspheres are passivated by a self-assembled monolayer of octadecylphosphonic acid, which suppresses the reaction between Li and commonly used slurry solvent 1-methyl-2-pyrrolidinone (NMP). After the addition of passivated Li-C into the NMP-based graphite slurry, the ICE of the graphite||Li half-cell boosts from 88.5% to 100.5%. In a 4.5 V LiCoO2 (LCO)||graphite full-cell, the supplementary Li source avoids excessive delithiation of LCO, thus suppressing the destructive phase transformation at high delithiation potential. As a result, the prelithiated LCO||graphite full-cell presents an initial discharge capacity of 201 mAh g-1 and the capacity retention after 100 cycles increases by 7.1 %. This work provides a practical approach for developing high energy density and long cycle life LIBs.

A triple protostar system formed via fragmentation of a gravitationally unstable disk.

Binary and multiple star systems are a frequent outcome of the star formation process and as a result almost half of all stars with masses similar to that of the Sun have at least one companion star. Theoretical studies indicate that there are two main pathways that can operate concurrently to form binary/multiple star systems: large-scale fragmentation of turbulent gas cores and filaments or smaller-scale fragmentation of a massive protostellar disk due to gravitational instability. Observational evidence for turbulent fragmentation on scales of more than 1,000 astronomical units has recently emerged. Previous evidence for disk fragmentation was limited to inferences based on the separations of more-evolved pre-main sequence and protostellar multiple systems. The triple protostar system L1448 IRS3B is an ideal system with which to search for evidence of disk fragmentation as it is in an early phase of the star formation process, it is likely to be less than 150,000 years old and all of the protostars in the system are separated by less than 200 astronomical units. Here we report observations of dust and molecular gas emission that reveal a disk with a spiral structure surrounding the three protostars. Two protostars near the centre of the disk are separated by 61 astronomical units and a tertiary protostar is coincident with a spiral arm in the outer disk at a separation of 183 astronomical units. The inferred mass of the central pair of protostellar objects is approximately one solar mass, while the disk surrounding the three protostars has a total mass of around 0.30 solar masses. The tertiary protostar itself has a minimum mass of about 0.085 solar masses. We demonstrate that the disk around L1448 IRS3B appears susceptible to disk fragmentation at radii between 150 and 320 astronomical units, overlapping with the location of the tertiary protostar. This is consistent with models for a protostellar disk that has recently undergone gravitational instability, spawning one or two companion stars.

A study on the impact of Internet use on depression among Chinese older people under the perspective of social participation.

PURPOSE: This study aimed to evaluate the role of social participation in the relationship between internet use and depressive symptoms among Chinese older adults and investigate how the internet use interact with social participation to reduce the risk of depressive symptoms. METHODS: Based on the survey from the China Health and Retirement Longitudinal Study (CHARLS) in 2018, we identified 4645 subjects and used the Ordinary Least Square method (OLS) and Propensity Score Matching method (PSM) to identify the association between Internet use and depression of older people, and further test how social participation played a role in the relationship. RESULTS: The level of depression of older people was significantly reduced in those who using internet in China, and the effect was still robust under different identification methods. The mental health was improved when using internet because of the increase of social participation and social capital. Further, The positive effect was stronger especially in those who were female, living in rural areas, has low education attainments and were 70-79 years old. CONCLUSIONS: The popularity of internet use has a positive effect on the depressive symptoms of Chinese older adults. Effective measures were encouraged to improve the friendliness of internet for older people and promote the popularization of the Internet and older group, achieving the spiritual well-being of them in the Internet society.

Posttraumatic growth and postpartum depression in women after childbirth: The moderating role of postpartum negative life events.

AIM: This study aimed to investigate the implications of postpartum negative life events on postpartum depression and posttraumatic growth in women after childbirth. METHODS: A sample of 280 postpartum women at a level III hospital in China provided data on postpartum depression, negative life events, and posttraumatic growth with a cross-sectional design. RESULTS: The scores of both postpartum depression and negative life events exhibited a quadratic correlation with posttraumatic growth in women after childbirth, and negative life events significantly moderated the associations between depression and overall posttraumatic growth and its three dimensions: personal strength, spirit change, and relating to others. CONCLUSIONS: Women can experience positive psychological growth after childbirth, and this study provides new evidence of an interaction between postpartum depression and negative life events in the prediction of psychological growth, highlighting the moderating role of negative life events. This study could help direct mental health professionals to target interventions that provide more psychological support to reduce the impact of depression and negative life events, which will be conducive to improving women's psychological growth.

Spatially resolved magnetic field structure in the disk of a T Tauri star.

Magnetic fields in accretion disks play a dominant part during the star formation process but have hitherto been observationally poorly constrained. Field strengths have been inferred on T Tauri stars and possibly in the innermost part of their accretion disks, but the strength and morphology of the field in the bulk of a disk have not been observed. Spatially unresolved measurements of polarized emission (arising from elongated dust grains aligned perpendicularly to the field) imply average fields aligned with the disks. Theoretically, the fields are expected to be largely toroidal, poloidal or a mixture of the two, which imply different mechanisms for transporting angular momentum in the disks of actively accreting young stars such as HL Tau (ref. 11). Here we report resolved measurements of the polarized 1.25-millimetre continuum emission from the disk of HL Tau. The magnetic field on a scale of 80 astronomical units is coincident with the major axis (about 210 astronomical units long) of the disk. From this we conclude that the magnetic field inside the disk at this scale cannot be dominated by a vertical component, though a purely toroidal field also does not fit the data well. The unexpected morphology suggests that the role of the magnetic field in the accretion of a T Tauri star is more complex than our current theoretical understanding.

Altered Cofactor Preference of Thermostable StDAPDH by a Single Mutation at K159.

D-amino acid production from 2-keto acid by reductive amination is an attractive pathway because of its high yield and environmental safety. StDAPDH, a meso-diaminopimelate dehydrogenase (meso-DAPDH) from Symbiobacterium thermophilum, was the first meso-DAPDH to show amination of 2-keto acids. Furthermore, StDAPDH shows excellent thermostability compared to other meso-DAPDHs. However, the cofactor of StDAPDH is NADP(H), which is less common than NAD(H) in industrial applications. Therefore, cofactor engineering for StDAPDH is needed. In this study, the highly conserved cofactor binding sites around the adenosine moiety of NADPH were targeted to determine cofactor specificity. Lysine residues within a loop were found to be critical for the cofactor specificity of StDAPDH. Replacement of lysine with arginine resulted in the activity of pyruvic acid with NADH as the cofactor. The affinity of K159R to pyruvic acid was equal with NADH or NADPH as the cofactor, regardless of the mutation. Molecular dynamics simulations revealed that the large steric hindrance of arginine and the interaction of the salt bridge between NADH and arginine may have restricted the free movement of NADH, which prompted the formation of a stable active conformation of mutant K159R. These results provide further understanding of the catalytic mechanism of StDAPDH and guidance for the cofactor engineering of StDAPDH.

Rice FLUORESCENT1 Is Involved in the Regulation of Chlorophyll.

Chlorophyll biosynthesis plays essential roles in photosynthesis and plant growth in response to environmental conditions. The accumulation of excess chlorophyll biosynthesis intermediates under light results in the production of reactive oxygen species and oxidative stress. In this study, we identified a rice (Oryza sativa) mutant, oxidation under photoperiod (oxp), that displayed photobleached lesions on its leaves, reduced growth and decreased chlorophyll content during light/dark cycles or following a dark-to-light transition. The oxp mutant accumulated more chlorophyll precursors (5-aminolevulinic acid and protochlorophyllide) than the wild type in the dark, and more singlet oxygen following light exposure. Several singlet-oxygen-responsive genes were greatly upregulated in oxp, whereas the expression patterns of OsPORA and OsPORB, two genes encoding the chlorophyll biosynthesis enzyme NADPH:protochlorop hyllide oxidoreductase, were altered in de-etiolated oxp seedlings. Molecular and complementation studies revealed that oxp is a loss-of-function mutant in LOC_Os01g32730, a homolog of FLUORESCENT (FLU) in Arabidopsis thaliana. Rice PHYTOCHROME-INTERACTING FACTOR-LIKE14 (OsPIL14) transcription factor directly bound to the OsFLU1 promoter and activated its expression. Dark-grown transgenic rice seedlings overexpressing OsPIL14 accumulated more chlorophyll and turned green faster than the wild type upon light illumination. Thus, OsFLU1 is an important regulator of chlorophyll biosynthesis in rice.

[Isoliquiritigenin can inhibit migration and invasion of human glioma stem cells by down-regulating matrix metalloproteinases].

OBJECTIVE: To investigate the effects of isoliquiritigenin on the migration and invasion of human glioma stem cells and the underlying mechanism. METHODS: The stem cell markers CD133 and Nestin in SHG44 human glioma stem cells were examined with immunofluorescence microscopy. The migration and invasion ability of glioma stem cells was determined by transwell method. The mRNA and protein expression of matrix metalloproteinase (MMP)-2 and MMP-9 were detected by real-time RT-PCR and Western blot, respectively. RESULTS: CD133 and Nestin were positive in SHG44 cells. The number of migrated cells in SHG44 cells treated with 20 and 80 µmol/L isoliquiritigenin for 48 h were significantly lower than that in control group (76±5 and 42±4 vs. 85±6, all P<0.01), and the number of migrated cells in 80 µmol/L isoliquiritigenin group was lower than that in 20 µmol/L isoliquiritigenin group (P<0.01). The numbers of cells crossing through membrane in 20 and 80 µmol/L isoliquiritigenin groups were 190±13 and 130±9, respectively, which were significantly lower than that in control group (230±14, all P<0.01), and the number of crossed cells in the 80 µmol/L isoliquiritigenin group was lower than that in 20 µmol/L isoliquiritigenin group (P<0.01). The mRNA and protein expression levels of MMP-2 and MMP-9 were decreased compared with control group (P<0.05 or P<0.01), and the expression levels in 80 µmol/L isoliquiritigenin group were lower than those in 20 µmol/L isoliquiritigenin group (P<0.05 or P<0.01). CONCLUSIONS: Isoliquiritigenin exhibits antitumor effects on glioma stem cells by inhibiting cell migration and invasion, which may be related to the down-regulation of MMP-2 and MMP-9.

Integrating Sugar and Dopamine into One Polymer: Controlled Synthesis and Robust Surface Modification.

Glycopolymers attached to a surface possess the ability to bind to certain carbohydrate binding proteins in a highly specific manner, and because of this, the fabrication of glycopolymer-modified surfaces has evolved as an effective route toward bioresponsive systems. Poly(N-3,4-dihydroxybenzenethyl methacrylamide-co-2-(methacrylamido) glucopyranose) copolymers, containing sugar and catechol functionalities, are for the first time successfully prepared in a well-controlled manner via room temperature single-electron transfer initiation and propagation through radical addition fragmentation chain transfer technique. The polymerization behavior is investigated and it presents controlled features with first-order kinetics and linear relationships between molecular weights and monomer conversions. Moreover, the copolymers are used to modify different types of surfaces (silicon, steel, and plastic), the properties of the surfaces and the specific lectin-binding abilities are investigated by a combination of water contact angle, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectra, scanning electron microscopy with energy dispersive X-ray (SEM/EDX), atomic force microscopy, and confocal microscope measurements.

The change of cervical spine alignment along with aging in asymptomatic population: a preliminary analysis.

STUDY DESIGN: A cross-sectional study. OBJECTIVE: To investigate the correlation of cervical spine alignment changes with aging in asymptomatic population. BACKGROUND: Previous studies demonstrated the influence of lumbar and thoracic spine on cervical spine alignment, but few has reported the cervical spine alignment change along with aging in asymptomatic population. METHODS: Asymptomatic population were divided into four groups according to different ages (Group A: ≤20 years; Group B: 21-40 years; Group C: 41-60 years; Group D: ≥61 years). Each group was composed of 30 subjects. The following parameters were measured: C0-1 Cobb angle, C1-2 Cobb angle, C2-7 Cobb angle, C1-7 sagittal vertical axis (C1-7 SVA), C2-7 SVA, central of gravity to C7 sagittal vertical axis (CG-C7 SVA), Thoracic Inlet Angle (TIA), Neck Tilt (NT), cervical tilt, cranial tilt, T1 slope (TS), TS-CL, and ANOVA statistical method was used to analyze the differences among four groups, and then, linear regression analysis was performed to analyze correlation of the cervical spine alignment with the aging. RESULTS: C1-7 SVA, C2-7 SVA, CG-C7 SVA, TIA, NT, TS, and cranial tilt were found statistically different among four groups (P < 0.01). From Group A to Group D, the mean C1-7 SVA were 30.7, 26.0, 21.8, and 36.9 mm, the mean C2-7 SVA were 18.7, 14.7, 11.9, and 24.7 mm, and the mean CG-C7 SVA were 19.6, 16.6, 9.4, and 26.7 mm. The mean TIA were 62.4°, 65.0°, 71.8°, and 76.9°, the mean NT were 39.4°, 43.8°, 46.3°, and 48.2°, the mean TS were 23.0°, 21.1°, 25.5°, and 28.7°, and the mean cranial tilt were 5.7°, 4.8°, 3.0°, and 9.5°. Further linear regression indicated that TIA (r = 0.472; P < 0.0001), NT (r = 0.337; P = 0.0006), and TS (r = 0.299; P = 0.0025) were positively correlated with aging. CONCLUSION: A gradual increase of TIA, NT, and TS, accompanied with an increased CL, is found along with aging in asymptomatic population, among which TIA, NT, and TS are significantly correlated with physiological nature of aging.

Débridement and Reconstruction Improve Postoperative Sagittal Alignment in Kyphotic Cervical Spinal Tuberculosis.

BACKGROUND: Cervical spinal tuberculosis is relatively common in some developing countries. It erodes vertebrae and discs, which sometimes results in cervical kyphosis and myelopathy. However, to our knowledge, no studies have evaluated improvements to patient-reported outcomes among patients who undergo surgical cervical sagittal realignment after kyphotic cervical spinal tuberculosis has been treated by débridement and reconstruction. QUESTIONS/PURPOSES: (1) Can a spine with kyphotic cervical spinal tuberculosis be returned to normal alignment and fused successfully? (2) Will patient-reported outcomes be improved with this intervention? (3) Are patient-reported outcomes correlated with realignment? METHODS: Forty-six patients with kyphotic cervical spinal tuberculosis were evaluated in this retrospective study. We generally performed surgery on patients with this condition when patients with cervical spinal tuberculosis presented with cervical kyphosis with or without neurologic deficits. Patients who did not meet these criteria were treated with other surgical procedures during the study period. Study patients were evaluated with cervical imaging, patient-reported outcomes questionnaires (Neck Disability Index [NDI], and the Japanese Orthopaedic Association [JOA] score), and physical examinations. Scores were collected by fellows preoperatively and at followup. No patient died during the followup. The mean followup was 26.8 months (range, 20-35 months). Preoperative and 2-year followup radiologic parameters were measured, including C0-2 Cobb angle, C2-7 Cobb angle, C2-7 sagittal vertical axis, center of gravity (CG) to C7 sagittal vertical axis (CG-C7 sagittal vertical axis), thoracic inlet angle, T1 slope, and neck tilt. The correlations between cervical alignment and the NDI and JOA score were analyzed. Factors correlated with the NDI and JOA score improvements were identified by multiple stepwise regression analysis. CT was used to assess bone fusion after surgery. RESULTS: All 46 patients showed bone fusion on CT scans. The preoperative C0-2 Cobb angle improved after surgery (mean difference, 5.0°; 95% CI, 2.3°-7.7°; p = 0.0068), as did C2-7 Cobb angle (mean difference, -33°; 95% CI, -35° to -31°; p = 0.0074), C2-7 sagittal vertical axis (mean difference, -28 mm; 95% CI, -30 mm to -26 mm; p = 0.0036), CG-7 sagittal vertical axis (mean difference, -26 mm; 95% CI, -28 mm to -24 mm; p = 0.0049), T1 slope (mean difference, 6.0°; 95% CI, 3.7°-8.3°; p = 0.0053) and the thoracic inlet angle (mean difference, 8.0°; 95% CI, 3.7°-12°; p = 0.0072). With the numbers available, the neck tilt angle did not improve (mean difference, -0.2°; 95% CI, -1.0° to 0.6°; p = 0.079). The preoperative NDI of 34 ± 5.1 decreased to 17 ± 4.6 (p = 0.0096) at followup. Improvements in NDI were correlated with the magnitude of correction of the cervical deformities, including C0-2 Cobb angle (r = -0.357, p = 0.007), C2-7 Cobb angle (r = 0.410, p = 0.002), T1 slope (r = -0.366, p = 0.006, thoracic inlet angle (r = -0.376, p = 0.005), C2-7 sagittal vertical axis (r = 0.450, p = 0.001), and CG-C7 sagittal vertical axis (r = 0.361, p = 0.007). The JOA score improved to 13 ± 2.6 from 7.2 ± 1.9, which did not correlate with postoperative cervical realignment. After controlling for potential confounding variables like Cobb angles and T1 slope, we found C2-7 sagittal vertical axis was the most influential factor correlated with NDI improvement (r = 0.450, p = 0.002). CONCLUSION: When treating kyphotic cervical spinal tuberculosis by débridement, decompression, and reconstruction, more attention should be drawn to realigning the cervical spine, in particular to restoring the C2-7 sagittal vertical axis. However, how best to restore the C2-7 sagittal vertical axis and cervical alignment in a kyphotic cervical spine needs further study. LEVEL OF EVIDENCE: Level III, therapeutic study.

The accuracy of the lateral vertebral notch-referred pedicle screw insertion technique in subaxial cervical spine: a human cadaver study.

STUDY DESIGN: This is a cadaver specimen study to confirm new pedicle screw (PS) entry point and trajectory for subaxial cervical PS insertion. OBJECTIVE: To assess the accuracy of the lateral vertebral notch-referred PS insertion technique in subaxial cervical spine in cadaver cervical spine. BACKGROUNDS: Reported morphometric landmarks used to guide the surgeon in PS insertion show significant variability. In the previous study, we proposed a new technique (as called "notch-referred" technique) primarily based on coronal multiplane reconstruction images (CMRI) and cortical integrity after PS insertion in cadavers. However, the PS position in cadaveric cervical segment was not confirmed radiologically. Therefore, the difference between the pedicle trajectory and the PS trajectory using the notch-referred technique needs to be illuminated. METHODS: Twelve cadaveric cervical spines were conducted with PS insertion using the lateral vertebral notch-referred technique. The guideline for entry point and trajectory for each vertebra was established based on the morphometric data from our previous study. After 3.5-mm diameter screw insertion, each vertebra was dissected and inspected for pedicle trajectory by CT scan. The pedicle trajectory and PS trajectory were measured and compared in axial plane. The perforation rate was assessed radiologically and was graded from ideal to unacceptable: Grade 0 = screw in pedicle; Grade I = perforation of pedicle wall less than one-fourth of the screw diameter; Grade II = perforation more than one-fourth of the screw diameter but less than one-second; Grade III = perforation more than one-second outside of the screw diameter. In addition, pedicle width between the acceptable and unacceptable screws was compared. RESULTS: A total of 120 pedicle screws were inserted. The perforation rate of pedicle screws was 78.3% in grade 0 (excellent PS position), 10.0% in grade I (good PS position), 8.3% in grade II (fair PS position), and 3.3% in grade III (poor PS position). The overall accepted accuracy of pedicle screws was 96.7% (Grade 0 + Grade I + Grade II), and only 3.3% had critical breach. There was no statistical difference between the pedicle trajectory and PS trajectory (p > 0.05). Compared to the pedicle width (4.4 ± 0.7 mm) in acceptably inserted screw, the unacceptably screw is 3.2 ± 0.3 mm which was statistically different (p < 0.05). CONCLUSION: The accuracy of the notch-referred PS insertion in cadaveric subaxial cervical spine is satisfactory.

Ratiometric Fluorescent pH Probes Based on Glycopolymers.

Effectively detecting pH changes plays a critical role in exploring cellular functions and determining physiological and pathological processes. A novel ratiometric pH probe based on a glycopolymer, armored with properties of serum-stability, tumor-targeting, and pH monitoring, is designed. Random copolymers of 2-(methacrylamido) glucopyranose and fluorescein O-methacrylate are first synthesized by reversible addition fragmentation chain transfer polymerization. Acryloxyethyl thiocarbamoyl rhodamine B is then attached to the polymer chain to prepare ratiometric fluorescent pH probes via a thiol-ene reaction. The synthesized polymeric probes are characterized by NMR, gel permeation chromatography, UV-vis spectroscopy, and transmission electron microscopy, and the fluorescence responses are examined in phosphate buffer at different pHs. The cytotoxicity and confocal imaging experiments of the probes are detected using HeLa cells, demonstrating a low toxicity and superior biocompatibility for detecting pH changes in bioapplications.

CrkL meditates CCL20/CCR6-induced EMT in gastric cancer.

BACKGROUND: In recent years, Crk-like adapter protein (CrkL) has been identified as a key regulator in the epithelial-to-mesenchymal transition (EMT). However, the molecular mechanisms underlying the CC chemokine receptor 6 (CCR6) and chemokine (C-C motif) ligand 20 (CCL20)-induced EMT in gastric cancer are still unclear. METHODS: We conducted the immunohistochemistry and immunoblotting to detect the expression of CCR6 and CrkL in 90 cases of gastric cancer tissues and five kinds of cell lines. And then, gastric cancer cells were subjected to small interfering RNA (siRNA) treatment and in vitro assay. RESULTS: Both CCR6 and CrkL were aberrantly expressed in gastric cancer specimens and closely correlated with differentiation of cell lines. The expression of CCR6 and CrkL was also significantly associated with metastasis, stage, and poor prognosis of gastric cancer. In addition, we validated CCL20 activated the expression of p-CrkL, p-Erk1/2, p-Akt, vimentin, N-cadherin and MMP2 in MGC803 cells in a dose-dependent manner. However, si-CrkL abrogated the CCL20-induced p-Erk1/2, vimentin, N-cadherin and MMP2 expression. Most importantly, the knockdown of CrkL decreased migration and invasion of MGC803 cells. CONCLUSIONS: CrkL mediates CCL20/CCR6-induced EMT via Akt pathway, instead of Erk1/2 pathway in development of gastric cancer, which indicated CCL20/CCR6-CrkL-Erk1/2-EMT pathway may be targeted to antagonize the progression of gastric cancer.