Polarized tip-enhanced Raman spectroscopy at liquid He temperature in ultrahigh vacuum using an off-axis parabolic mirror

Tip-enhanced Raman spectroscopy (TERS) combines inelastic light scattering well below the diffraction limit down to the nanometer range and scanning probe microscopy and, possibly, spectroscopy. In this way, topographic and spectroscopic as well as single- and two-particle information may simultaneously be collected. While single molecules can now be studied successfully, bulk solids are still not meaningfully accessible. It is the purpose of the work presented here to outline approaches toward this objective. We describe a home-built, liquid helium cooled, ultrahigh vacuum TERS. The setup is based on a scanning tunneling microscope and, as an innovation, an off-axis parabolic mirror having a high numerical aperture of ∼0.85 and a large working distance. The system is equipped with a fast load-lock chamber, a chamber for the in situ preparation of tips, substrates, and samples, and a TERS chamber. Base pressure and temperature in the TERS chamber were ∼3 × 10-11 mbar and 15 K, respectively. Polarization dependent tip-enhanced Raman spectra of the vibration modes of carbon nanotubes were successfully acquired at cryogenic temperature. The new features described here including very low pressure and temperature and the external access to the light polarizations, thus the selection rules, may pave the way toward the investigation of bulk and surface materials.

AZD4547 and the Alleviation of Hepatoma Cell Sorafenib Resistance via the Promotion of Autophagy

Background This study is part of a larger research effort to explore the molecular mechanism of hepatocellular carcinoma, reduce drug resistance and seek new targets. Objective To investigate the effect and mechanism of fibroblast growth factor receptor inhibitor AZD4547 on Sorafenib-resistant hepatoma cells. Methods First we constructed a Sorafenib-resistant hepatoma cell line Huh7R. Different groups of Huh7R cells were treated with Sorafenib, AZD4547, Sorafenib combined with AZD4547, and normal saline. The cell viability was detected by Cell Counting Kit-8. Then Fibroblast growth factor receptor and Toll-like receptor 4 were detected by Western blot, as well as the LC3 II/I, Beclin1, and P62. In addition, we used the autophagy inhibitor 3-methyladenine to identify the mechanism of AZD4547 combined with Sorafenib for inducing Sorafenib-resistant hepatoma cell death. Results We find that AZD4547 combined with Sorafenib significantly inhibited the viability of Sorafenib-resistant hepatoma cell Huh7R. As for its mechanism, AZD4547 was able to inhibit fibroblast growth factor receptor activity, promote autophagy and regulate immunity. AZD4547 increased LC3 II/I, Beclin1, and Toll-like receptor 4 proteins, and decreased P62 protein level in Huh7R cells significantly when given in combination with sorafenib. Furthermore, 3-methyladenine inhibited autophagy and reversed the killing effect of the combination of AZD4547 and Sorafenib on Huh7R cells. Conclusion The inhibition of fibroblast growth factor receptor activity by AZD4547 can significantly enhance autophagy and immune response, as well as promote the death of Sorafenib-resistant hepatoma cells.

Analysing neutron radiation damage in YBa2 Cu3 O7-x high temperature superconductor tapes

Superconducting windings will be necessary in future fusion reactors to generate the strong magnetic fields needed to confine the plasma, and these superconducting materials will inevitably be exposed to neutron damage. It is known that this exposure results in the creation of isolated damage cascades, but the presence of these defects alone is not sufficient to explain the degradation of macroscopic superconducting properties and a quantitative method is needed to assess the subtle lattice damage in between the clusters. We have studied REBCO coated conductors irradiated with neutrons to a cumulative dose of 3.3×10²²  n*m^-2  that show a degradation of both T_c  and J_c values, and use HRTEM analysis to show that this irradiation introduces ∼10 nm amorphous collision cascades. In addition we introduce a new method for the analysis of these images to quantify the degree of lattice disorder in the apparently perfect matrix between these cascades. This method utilises Fast Fourier and Discrete Cosine Transformations of a statistically-relevant number of HRTEM images of pristine, neutron-irradiated, and amorphous samples, and extracts the degree of randomness in terms of entropy values. Our results show that these entropy values in both mid-frequency band FFT and DCT domains correlate with the expected level of lattice damage, with the pristine samples having the lowest and the fully amorphous regions the highest entropy values.  Our methodology allows us to quantify 'invisible' lattice damage to and correlate these values to the degradation of superconducting properties, and also has relevance for a wider range of applications in the field of electron microscopy where small changes in lattice perfection need to be measured. This article is protected by copyright. All rights reserved.

[Mn2+-doped Prussian blue nanoparticles for T1-T2 dual-mode magnetic resonance imaging and photothermal therapy in vitro]

OBJECTIVE

To prepare Mn²⁺-doped Prussian blue nanoparticles (Mn-PB NPs) for T1-T2 dual-mode magnetic resonance imaging (MRI) and photothermal therapy in vitro.

OBJECTIVE

Mn-PB NPs were prepared based on manganese chloride, ferrous chloride and potassium ferricyanide using the microemulsion method. The performance of T1-T2 dual-mode MRI with Mn-PB NPs and the photothermal property of the nanoparticles were assessed. CCK-8 assay and AM/PI double staining were used to evaluate the effect of photothermal therapy in vitro using the parepared nanoparticles.

OBJECTIVE

The prepared Mn-PB NPs had a mean particle size of 39.46±0.42 nm with a Zeta potential of -25.9±1.2 mV and exhibited a good dispersibility and uniform particle size. In MRI using the nanoparticles, the r1 and r2 values reached 0.68 and 3.65 (mmol/L)^-1s^-1, respectively, indicating good performance of Mn-PB NPs for T1 and T2 enhancement in MRI. When irradiated with 808 nm laser for 10 min, Mn-PB NPs showed a temperature rise to 90 ℃ to cause significant reduction of cell survival. CCK-8 assay and AM/PI double staining confirmed that Mn-PB NPs were capable of efficient killing of HepG2 cells upon 808 nm laser irradiation.

OBJECTIVE

The Mn-PB NPs prepared in this work have uniform particle size and show good performances both in MRI for T1 and T2 enhancement and in photothermal therapy in vitro without obvious cytotoxicity.

Histological analysis of spermatogenesis and the germ cell seasonal development within the testis of domesticated tree shrews (Tupaia belangeri chinensis)

This study aimed to address the lack of information on the male germ cell seasonal development of domesticated tree shrews (Tupaia belangeri chinensis). Testicular tissues were collected from 60 tree shrews (n=5 per month). The ultrastructures of the testes and spermatids were examined via transmission electron microscopy. Apoptosis of spermatogenic cells was measured through terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. The expression of proliferation factors, namely, proliferating cell nuclear antigen (PCNA) and Ki67, in testicular tissues was assayed through immunohistochemistry. Spermatids ultrastructure showed seasonal differences, and spermatogenesis was relatively active in June and July and relatively stagnant from October to November. The percentage of TUNEL-positive germ cells was less during October and November, while greater in July than other phases. The number of PCNA-nucleus-positive germ cells was most in June and July, but with cytoplasm staining from October to November. Ki67 presented positive expression in the testes from April to September, with highest expression in June, but with no expression from October to March. In summary, there are seasonal differences in tissue morphology related to spermatogenesis in domesticated tree shrews. PCNA expression and Ki67 expression are good indicators of seasonal differences in male germ cells.

Remote Mesoscopic Signatures of Induced Magnetic Texture in Graphene

Mesoscopic conductance fluctuations are a ubiquitous signature of phase-coherent transport in small conductors, exhibiting universal character independent of system details. In this Letter, however, we demonstrate a pronounced breakdown of this universality, due to the interplay of local and remote phenomena in transport. Our experiments are performed in a graphene-based interaction-detection geometry, in which an artificial magnetic texture is induced in the graphene layer by covering a portion of it with a micromagnet. When probing conduction at some distance from this region, the strong influence of remote factors is manifested through the appearance of giant conductance fluctuations, with amplitude much larger than e^{2}/h. This violation of one of the fundamental tenets of mesoscopic physics dramatically demonstrates how local considerations can be overwhelmed by remote signatures in phase-coherent conductors.

Raman Study of Cooper Pairing Instabilities in (Li_{1-x}Fe_{x})OHFeSe

We studied the electronic Raman spectra of (Li_{1-x}Fe_{x})OHFeSe as a function of light polarization and temperature. In the B_{1g} spectra alone we observe the redistribution of spectral weight expected for a superconductor and two well-resolved peaks below T_{c}. The nearly resolution-limited peak at 110  cm^{-1} (13.6 meV) is identified as a collective mode. The peak at 190  cm^{-1} (23.6 meV) is presumably another collective mode since the line is symmetric and its energy is significantly below the gap energy observed by single-particle spectroscopies. Given the experimental band structure of (Li_{1-x}Fe_{x})OHFeSe, the most plausible explanations include conventional spin-fluctuation pairing between the electron bands and the incipient hole band and pairing between the hybridized electron bands. The absence of gap features in A_{1g} and B_{2g} symmetry favors the second case. Thus, in spite of various differences between the pnictides and chalcogenides, this Letter demonstrates the proximity of pairing states and the importance of band structure effects in the Fe-based compounds.

Universal scaling of weak localization in graphene due to bias-induced dispersion decoherence

The differential conductance of graphene is shown to exhibit a zero-bias anomaly at low temperatures, arising from a suppression of the quantum corrections due to weak localization and electron interactions. A simple rescaling of these data, free of any adjustable parameters, shows that this anomaly exhibits a universal, temperature- (T) independent form. According to this, the differential conductance is approximately constant at small voltages (V < kBT/e), while at larger voltages it increases logarithmically with the applied bias. For theoretical insight into the origins of this behaviour, which is inconsistent with electron heating, we formulate a model for weak-localization in the presence of nonequilibrium transport. According to this model, the applied voltage causes unavoidable dispersion decoherence, which arises as diffusing electron partial waves, with a spread of energies defined by the value of the applied voltage, gradually decohere with one another as they diffuse through the system. The decoherence yields a universal scaling of the conductance as a function of eV/kBT, with a logarithmic variation for eV/kBT > 1, variations in accordance with the results of experiment. Our theoretical description of nonequilibrium transport in the presence of this source of decoherence exhibits strong similarities with the results of experiment, including the aforementioned rescaling of the conductance and its logarithmic variation as a function of the applied voltage.

Effects of wet atmospheric nitrogen deposition on epiphytic lichens in the subtropical forests of Central China: Evaluation of the lichen food supply and quality of two endangered primates

Over the last few decades, the threat posed to biodiversity and ecosystem function by atmospheric nitrogen (N) deposition has been increasingly recognized. The disturbed nutrient balance and species composition of plants induced by higher N deposition can impact the biodiversity of the organisms that consume the plants. In this research, we implemented several experiments to estimate the effects of increased N deposition on the growth, survival, and nutrients of the dominant epiphytic lichens in the subtropical mountains in Central China to assess the lichen food amount and nutritional quality for two endangered primates endemic to China. Our results indicated that the thallus growth and propagule survival of the lichens were significantly decreased when nitrogen addition changed from 6.25 to 50.0 kg N·ha^-1·y^-1; it was also shown that lichen biomass could be decreased by 11.2%-70.2% when the deposition addition exceeded 6.25 kg N·ha^-1·y^-1. Further, our study revealed that increased nitrogen deposition also reduced the nutritional quality of the lichens via reducing the soluble protein and soluble sugar levels and increasing the fiber content, which would substantially affect the diet selection of the plants consumers in the region, particularly the populations of the two lichen-eating endangered primate species, Rhinopithecus roxellana and R. bieti. Our experimental study suggested that the nitrogen pollution derived from anthropogenic activities could cause cascading effects for the whole forest ecosystem of Central China; thus, more studies about nitrogen deposition in this region are required.

Isolation of H8N4 avian influenza virus from wild birds in Shanghai, China

The H8 subtype viruses are rarely isolated from wild ducks. Shanghai is one of the important wintering or stopover sites on the East Asia-Australia Migration Flyway. An influenza virus, subtype H8N4, was firstly isolated from a common teal (Anas crecca) in Shanghai during 2017-2018 in this study. To clarify the genetic characteristics of the H8N4 virus, the whole genome sequences were analyzed. Phylogenetic analysis of the hemagglutinin and neuraminidase genes showed that they shared highest nucleotide identity (99.19%-99.64%) with the Japan duck-origin H8N4 virus collected in 2016 (A/duck/Aichi/231003/2016) and belonged to the Eurasian-like avian lineage. Six other genes of the H8N4 isolated virus were all highly similar to the corresponding genes of a wide range of AIV subtypes including H9N2, H5N7, H3N8, H1N2, H4N6 and H1N1. The results indicated that the H8N4 virus was a multiple reassortant virus. The study emphasized that the continuous surveillance of influenza virus in wild birds should be strengthened. Keywords: avian influenza virus; H8N4; phylogenetic analysis; Shanghai.

Application of plasma circulating cell-free DNA detection to the molecular diagnosis of hepatocellular carcinoma

Circulating tumor DNA (ctDNA) carries genetic information consistent with tumor cells and has potential value for molecular diagnosis of tumors. The present study analysed the gene mutations of plasma circulating cell-free DNA (cfDNA) and tumor tissue DNA in hepatocellular carcinoma (HCC) patients and explored the clinical application value of plasma cfDNA as a tumor marker in HCC molecular diagnosis. Samples from 29 patients with primary HCC were collected. Hotspot mutations in 50 tumor-associated genes were analysed using amplicon sequencing technology and gene loci with a mutant allele frequency (MAF) >1% were analysed. 35 mutant genes in total were detected by deep sequencing method of which the genes with maximum mutation frequencies were TP53, ATM, and ALK. In addition, a total of 21 patients were found to have a consistent gene mutation in plasma cfDNA and tumor tissue DNA and 17 cases had consistent gene mutations in the paracancerous tissue and tumor tissue DNA. Further analysis showed that the MAFs in the TP53, CTNNB1, PIK3CA, and CDKN2A genes were higher in patients with tumor diameters >5 cm than those with tumor diameters <5 cm. And the MAFs in the TP53, RET, FGFR3 and APC genes were significantly higher in patients with multiple tumors or with metastasis than in single tumor patients. In conclusion, amplicon sequencing technology is highly sensitive for the detection of mutant genes in the plasma cfDNA of HCC patients. Plasma cfDNA might be an effective molecular marker for HCC molecular diagnosis.

Semi-dominant mutation in the cysteine-rich receptor-like kinase gene, ALS1, conducts constitutive defence response in rice

Plants have evolved a sophisticated two-branch defence system to prevent the growth and spread of pathogen infection. The novel Cys-rich repeat (CRR) containing receptor-like kinases, known as CRKs, were reported to mediate defence resistance in plants. For rice, there are only two reports of CRKs. A semi-dominant lesion mimic mutant als1 (apoptosis leaf and sheath 1) in rice was identified to demonstrate spontaneous lesions on the leaf blade and sheath. A map-based cloning strategy was used for fine mapping and cloning of ALS1, which was confirmed to be a typical CRK in rice. Functional studies of ALS1 were conducted, including phylogenetic analysis, expression analysis, subcellular location and blast resistance identification. Most pathogenesis-related (PR) genes and other defence-related genes were activated and up-regulated to a high degree. ALS1 was expressed mainly in the leaf blade and sheath, in which further study revealed that ALS1 was present in the vascular bundles. ALS1 was located in the cell membrane of rice protoplasts, and its mutation did not change its subcellular location. Jasmonic acid (JA) and salicylic acid (SA) accumulation were observed in als1, and enhanced blast resistance was also observed. The mutation of ALS1 caused a constitutively activated defence response in als1. The results of our study imply that ALS1 participates in a defence response resembling the common SA-, JA- and NH1-mediated defence responses in rice.

Etching gas-sieving nanopores in single-layer graphene with an angstrom precision for high-performance gas mixture separation

One of the bottlenecks in realizing the potential of atom-thick graphene membrane for gas sieving is the difficulty in incorporating nanopores in an otherwise impermeable graphene lattice, with an angstrom precision at a high-enough pore density. We realize this design by developing a synergistic, partially decoupled defect nucleation and pore expansion strategy using O₂ plasma and O₃ treatment. A high density (ca. 2.1 × 10¹² cm^-2) of H₂-sieving pores was achieved while limiting the percentage of CH₄-permeating pores to 13 to 22 parts per million. As a result, a record-high gas mixture separation performance was achieved (H₂ permeance, 1340 to 6045 gas permeation units; H₂/CH₄ separation factor, 15.6 to 25.1; H₂/C₃H₈ separation factor, 38.0 to 57.8). This highly scalable pore etching strategy will accelerate the development of single-layer graphene-based energy-efficient membranes.

[The treatment of nose-eye correlated diseases with external nasal incision combined with nasal cavity approach surgery through endoscope]

Objective:To explore the indications and characteristics for the treatment of nose-eye correlated diseases with endoscopic surgery through external nasal incision combined with nasal cavity approach.Method:The clinical data of 13 patients whom hospitalized in our department and treated by endoscopic surgery through external nasal incision combined with nasal cavity approach since October 2011, were retrospectively analyzed and the characteristics of different pathological changes, clinical manifestations, surgical approach and follow-up results were summarized.Four cases of patients underwent endoscopic surgery through nasal cavity and lacrimal caruncle conjunctival incision, 4 cases received bone fracture reduction and DCR with endoscope through double path of nasal cavity and the original trauma wound, 2 cases with endoscopic bone tumor resection through nasal cavity and external nasal incision, the rest of the 3 cases with endonasal endoscopic and peri-orbit incision surgery.Result:Two cases of tumor patients showed no recurrence followed up for 1.5 to 2 years; the diplopia disappeared in 2 cases of orbital medial wall fracture; surgeries of 4 cases of orbital wall fracture with lacrimal duct obstruction patients, 3 cases succeeded, 1 case failed and change into dacryocystorhinotomy with external nasal incision, and epiphora of all patients vanished; all of the patients of sinus osteoma, foreign bodies and abscess were cured and symptoms disappeared; the symptoms of ectopic meningioma patient gradually died down with eyebrow scars left.Conclusion:The surgery with external nasal incision combined with nasal cavity approach through endoscope to treat noseeye correlated diseases can effectively deal with relevant pathological changes, with the advantages of clear operation field and less damage, but its exact indications and surgical methods still need to be further explored.

Total synthesis of teixobactin and its stereoisomers

The total syntheses of teixobactin and a series of its stereoisomers at positions 2, 5, 6, 10 and 11 were achieved via a combined strategy of solution and solid phase peptide synthesis.

High throughput in vitro and in vivo screening of inland waters of Southern California

The impact of unmonitored contaminants, also known as contaminants of emerging concern (CECs), on freshwater streams remains largely uncharacterized. Water samples from 31 streams representing urban, agricultural and undeveloped (i.e., open space) land use in Southern California (USA) were analyzed for in vitro and in vivo bioactivity. The extent and magnitude of bioactivity screened using endocrine-responsive cell bioassays and a fish embryo screening assay were low. In contrast, a wider gradient of responses for the aryl hydrocarbon receptor (AhR) assay was observed, which was negatively correlated with a measure of benthic community structure. Both aromatic and non-aromatic CECs were tentatively identified in these samples, but polycyclic aromatic hydrocarbons (PAHs), known AhR agonists in urban environments, were not present at detectable levels. These results suggest that a combination of in vitro and in vivo show potential as screening techniques for biological condition in situ, but that more advanced, comprehensive analytical methods are needed to identify bioactive contaminants.

[The study of locating facial nerve precisely in middle ear surgery based on clinical anatomy]

Objective:To investigate the methods of locating facial nerve precisely in middle ear surgery through the observation and measurement of the facial nerve and surrounding anatomical structures and to provide reference for the middle ear surgery.Method:Combined surgical approach on 15 cases (30 sides) fresh adult cadaveric specimens were dissected, observed the characteristics of facial nerve and its shape and spatial relationship of the surrounding structures, and measured the distance between the facial nerve and its surrounding structures.Result:The shortest distance from the midpoint of the posterior wall of external auditory canal (annulus level) to the vertical segment of the facial nerve was (3.37±0.34)mm, the shortest distance from the leading edge of the sigmoid sinus to the vertical segment of facial nerve was (7.40±0.71)mm, the shortest distance from the lateral margin of jugular bulb to the facial nerve was (5.58±0.79)mm, the shortest distance from Henle crest to the pyramidal segment of facial nerve was (12.76±1.24)mm, the shortest distance between the pyramidal segment of facial nerve and the posterior short limb of incus was (1.56±0.35)mm, the shortest distance between the pyramidal segment of facial nerve and the lower edge of posterior semicircular canal was (2.56±0.41) mm, the shortest distance between the lower edge of horizontal semicircular canal and the horizontal segment of facial nerve was (1.28±0.32) mm, the shortest distance between the upper edge of vestibular window and the horizontal segment of facial nerve was (0.67±0.15)mm.Conclusion:A good command of the anatomy of temporal bone as well as the methods of locating facial nerve will provide the key to reduce the probability of iatrogenic facial nerve injury in middle ear surgery.

Contrast-enhanced ultrasound in the diagnosis of orbital space-occupying lesions

AIM

To summarise the sonographic findings and assess the feasibility of contrast-enhanced ultrasound (CEUS) as an imaging method for the diagnosis of orbital space-occupying lesions.

MATERIALS AND METHODS

This was a prospective study of 53 patients who underwent orbital ultrasound at Xijing Hospital. Two-dimensional ultrasound, colour Doppler flow imaging (CDFI), and CEUS imaging were obtained and compared in patients with orbital haemangioma, pseudotumour, melanoma of the choroid, and retinoblastoma.

RESULTS

CEUS imaging cannot only visualise the location, shape, border, acoustic properties of a lesion, and interactions between the lesion and surrounding tissues, but also display the microvasculature and tissue perfusion within the lesion. The information obtained from CEUS imaging is valuable for diagnosis and differential diagnosis of orbital space-occupying lesions.

CONCLUSION

CEUS imaging allowed better visualisation of the lesions, enabled detection of vascular changes, increased the signal-to-noise ratio, and increased the sensitivity of detection of changes in perfusion in the microcirculation. It has relatively high sensitivity and specificity in the diagnosis of orbital space-occupying lesions and increases the accuracy of diagnosis.

Tumour-activated liver stromal cells regulate myeloid-derived suppressor cells accumulation in the liver

Regulating mechanisms underlying hepatic myeloid-derived suppressor cell (MDSC) accumulation remain to be described. Here, we provide evidence for the involvement of tumour-activated liver stromal cells in the process of hepatic MDSCs migration and accumulation. Our data showed an elevated frequency of MDSCs in the liver of tumour-bearing mice. Moreover, tumour-activated liver stromal cells promote MDSC migration into the liver site. Further investigation indicated higher levels of cytokine and chemokine expression in liver stromal cells after exposure to the tumour-conditioned supernatant. Notably, the expression levels of proinflammatory factors, mainly including macrophage colony stimulating factor (M-CSF), transforming growth factor-β (TGF-β), monocyte chemotactic protein-1 (MCP-1) and stromal-derived factor-1 (SDF-1), increased after treatment with tumour-conditioned supernatant, and blockade of MCP-1 or SDF-1 decreased the proportion of tumour infiltrated MDSCs in mice co-transplanted with liver stromal cells and tumour cells, but not in mice with only tumour cells injection. These findings demonstrate that tumour-activated liver stromal cells produce higher levels of chemokines and cytokines, which may contribute to MDSC accumulation into the liver site in patients with liver cancer.

Simultaneous detection of 45 fusion genes in leukemia by dual-color fluorescence real-time PCR

INTRODUCTION

Detection of recurrent genetic abnormalities is of great significance for a refined diagnosis and assessment of prognosis in leukemia. Conventional nested reverse transcription PCR is labor intensive and time-consuming.

METHODS

We have developed a novel dual-color TaqMan probe-based real-time PCR method for the simultaneous screening of 45 fusion transcripts in 12 parallel reactions. The method was tested and validated with cell lines carrying known fusion transcripts and patient samples.

RESULTS

A multiplex real-time PCR method was successfully developed for rapid detection of 45 fusion genes and validated for 15 of the more commonly detected fusion genes. Intra-assay reproducibility assessed for the most frequent rearrangements ranged from 0.41% to 0.74% for the coefficient of variation (CV) of cycle threshold (Ct) and the interassay reproducibility ranged from 1.62% to 2.83% in five separate experiments. The lowest detection limit for the translocations tested ranged between 1 : 16 000 and 1 : 32 000. Validation of the method with 213 patient samples showed 100% specificity and excellent consistence with conventional nested RT-PCR.

CONCLUSION

Overall, we believe that this method is easily applicable, cost-effective, and clinically useful for a rapid screening of fusion genes in the initial diagnostic phase of leukemia. Its use can also be extended to the monitoring of minimal residual disease.

[Endonasal endoscopic surgery in treatment of medial recus muscle entrapment: the management and effectiveness]

Objective:To explore the indications , surgery method and effect for the treatment of medial rectus muscle entrapment with endoscopic surgery.Method: Eight medial rectus muscle entrapment patients were enrolled in this study,3 cases underwent obital medial wall fracture reposition and medial rectus muscle adhesion decomposition surgery through endonasal endoscope,and 5 cases received obital medial wall fracture reposition surgery with endoscope through nasal cavity and lacrimal caruncle conjunctival incision. Result:The diplopia disappeared and eyeball abduction function recovered in 6 cases of medial rectus muscle entrapment patients within 2 months,and 1 case with each surgery had mild diplopia and eyeball incomplete abduction left.Conclusion:Adopting endonasal endoscopic surgery or dual approaches surgery with endonasal endoscopic and transcaruncular surgery were ideal methods for medial rectus muscle entrapment diseases.Surgery with endoscope has the characteristics of clear field and less damage.The surgery should be performed whithin 3 weeks, and the entrapment of medial rectus muscle can be resoved effectively.

Thermally Assisted Nonvolatile Memory in Monolayer MoS2 Transistors

We demonstrate a novel form of thermally-assisted hysteresis in the transfer curves of monolayer MoS₂ FETs, characterized by the appearance of a large gate-voltage window and distinct current levels that differ by a factor of ∼10². The hysteresis emerges for temperatures in excess of 400 K and, from studies in which the gate-voltage sweep parameters are varied, appears to be related to charge injection into the SiO₂ gate dielectric. The thermally-assisted memory is strongly suppressed in equivalent measurements performed on bilayer transistors, suggesting that weak screening in the monolayer system plays a vital role in generating its strongly sensitive response to the charge-injection process. By exploiting the full features of the hysteretic transfer curves, programmable memory operation is demonstrated. The essential principles demonstrated here point the way to a new class of thermally assisted memories based on atomically thin two-dimensional semiconductors.

[Outcomes of total deafness type of idiopathic suddendeafness in different ages]

Objective:This retrospective study was aimed to investigate the characteristics of hearing recovery in the complete deafness type of SSNHL(≥81 dBHL) in patients with different ages.Method:Clinical outcomes of 179 total deafness type of idiopathic sudden deafness were compared.Patients were divided into 5 groups according to age,they were,pediatric group(13 years or less),youthful group(14-44 years),middle-aged group(45-59 years),presenium group(60-74 years),senectitude group(75 years or higher).Patients were divided into 3 groups according to the initial degree of hearing loss: 81 dB group (81-89 dBHL),90 dB group(90- 99 dBHL),100 dB group(100 dBHL or higher).Routine comprehensive treatment including corticosteroids,the inner ear microcirculation improvement drugs,neurotrophic drugs,saturationoxygen and hyperbaric oxygen therapy,etc.was applied.Patients were treated in accordance with the age and body weight.Result:The percentage of youthful group(83/179,46.4%) was highest(P<0.05),middle-aged group(57/179,31.8%)followed(P<0.05),presenium group(26/179,14.5%)was lower(P<0.05),pediatric group(8/179,4.5%) and senectitude group(5/179,2.8%)were the lowest.No a complete recovery in either pediatric group or senectitude group.A complete recovery was rare in the other groups.Recovery rate of the different aged groups was similar(P>0.05).The percentage of 100 dB group(108/179,60.3%) was highest(P<0.05).The percentage of 81 dB group(39/179,21.8%)was similar to 90 dB group(32/179,17.9%)(P>0.05).Recovery rate was similar in 81 dB group(25/39,64.1%)and 90 dB group(18/32,56.2%)(P>0.05).Recovery rate of both 81 dB group and 90 dB group were greater than 100 dB group(24/108,22.2%)(P<0.05).The 100 dB group reduced the satisfactory recovery effects.There were no differences in the proportion of the patients with dizziness(95/179,53.1%)and without dizziness(84/179,46.9%)(P>0.05).Recovery rate of patients without dizziness(43/84,51.2%) was greater than with dizziness(24/95,25.3%)(P<0.05).The percentage of the patients without dizziness(31/39,79.5%)in 81 dB group was the highest(P<0.05),90 dB group(18/32,56.2%)followed(P<0.05).The percentage of the patients with dizziness in 100 dB group(73/108,67.6%)was highest(P<0.05).Recovery rate was similar in the patients without dizziness of 81 dB group(21/31,67.7%)and 90 dB group(11/18,61.1%)(P>0.05).Recovery rate of the above two groups was greater than that of 100 dB group(11/35,31.4%)(P<0.05).Conclusion:Recovery rate of the different aged groups was similar.The percentage of the patients with dizziness in 100 dB group was highest.Initial hearing threshold in excess of 100 dB reduced the satisfactory recovery in patients with total deafness type of SSNHL.Our results provided a good reference for other clinicians.

Tristetraprolin: a novel mediator of the anticancer properties of resveratrol

Resveratrol is a natural compound that exhibits anticancer properties. Previous studies have proved that it can inhibit the proliferation of breast cancer cell lines and upregulate some cytokines such as cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF). The initiation and progression of cancer are associated with the abnormal expression of multiple cytokines. Tristetraprolin (TTP), an mRNA-binding protein, is one of the key proteins that participate in regulating cytokine expression. Two different proliferation assays on MCF-7 cells showed that the cell proliferation rate significantly reduced following treatment with resveratrol. Most importantly, we found that resveratrol promoted TTP expression at both the mRNA and protein level in a dose- and time-dependent manner. In addition, the expression of COX-2 and VEGF were significantly suppressed by resveratrol while that of inducible nitric oxide synthase (iNOS) was upregulated. Lastly, the effects of resveratrol on both MCF-7 proliferation and expression of COX-2, VEGF, and iNOS were significantly inhibited by TTP knockdown, indicating that TTP mediates the anticancer properties of resveratrol. In summary, we conclude that resveratrol inhibits the proliferation of MCF-7 cells by TTP upregulation, which is associated with downregulation of COX-2 and VEGF and upregulation of iNOS.

Gut-derived lymphocyte recruitment to liver and induce liver injury in non-alcoholic fatty liver disease mouse model

BACKGROUND AND AIM

Most studies focus on gut-derived factors like microbiota and its products and how they contribute to non-alcoholic fatty liver disease (NAFLD) progression. This study investigated whether the gut-derived lymphocytes could migrate to the liver and induce liver injury in NAFLD.

METHODS

A high-fat diet induced an NAFLD mouse model, and lymphocytes were labeled with 1,1-dioctadecyl-3,3,3,3 tetramethylindotricarbocyanine iodide and carboxy-fluorescein succinimidyl ester, respectively, and intravenously injected to mice to monitor lymphocyte migration.

RESULTS

Adoptive transfer model results indicated that compared with lymphocytes from the spleen, bone marrow and thymus of NAFLD donor mice, mesenteric lymph nodes (MLN) cells from NAFLD donor mice predominately accumulated in the livers of NAFLD recipient mice. The frequencies of central memory CD4(+) T and CD8(+) T cells in livers of NAFLD mice were significantly increased; however, the activated T cells were not significantly altered. After adoptively transferred MLN cells, the frequencies of the activated CD4(+) T and CD8(+) T cells increased in livers of NAFLD recipient mice. By contrast, the frequencies of central memory and naïve CD4(+) T and CD8(+) T cells decreased. MLN cells also induced liver injury in NAFLD recipient mice, as reflected by elevated serum alanine aminotransferase and glutamic oxaloacetic transaminase serums. Moreover, the chemotaxis assay showed that CCL5 mediated the MLN cell migration to the liver. Also, blocking the CCL5 inhibited MLN cell migration to the liver in vitro.

CONCLUSIONS

Gut-derived lymphocytes from NAFLD mice could migrate to the liver and induce liver injury and hepatic CD4(+) T and CD8(+) T cells activation. The migration was associated with the upregulation of CCL5 in the liver.

"Freeing" Graphene from Its Substrate: Observing Intrinsic Velocity Saturation with Rapid Electrical Pulsing

Rapid (nanosecond-scale) electrical pulsing is used to study drift-velocity saturation in graphene field-effect devices. In these experiments, high-field pulses are utilized to drive graphene's carriers on time scales much faster than that on which energy loss to the underlying substrate can occur, thereby allowing the observation of the highest saturation velocities reported to date. In a dramatic departure from the behavior exhibited by conventional metals and semiconductors, as the electron or hole density is reduced toward the charge-neutrality point, the drift velocity is found to reach values comparable to the Fermi velocity itself. Corresponding current densities are as large as 10(9) A/cm(2), similar to the values reported for carbon nanotubes and for graphene-on-diamond transistors. In essence, our approach of rapid pulsing allows us to "free" graphene from the deleterious influence of its substrate, revealing a pathway to achieve the superior electrical performance promised by this material. The usefulness of this approach is not merely limited to graphene but should extend also to a broad variety of two-dimensional semiconductors.

Block copolymer synthesis by controlled/living radical polymerisation in heterogeneous systems

We review the range of CLRP-controlled syntheses of block copolymer particles in dispersed systems, which are being exploited to create new opportunities for the design of nanostructured soft materials.

Palladium-catalyzed arylation of β-methylene C(sp3)–H bonds at room temperature: desymmetrization of simple cycloalkyl carboxylic acids

A new protocol for Pd-catalyzed β methylene C–H arylation of N-quinolyl cycloalkylcarboxamides with aryl iodides at room temperature is reported.

Hippocampal neurogenesis in the APP/PS1/nestin-GFP triple transgenic mouse model of Alzheimer's disease

Alzheimer's disease (AD) is one of the most common causes of dementia. Although the exact mechanisms of AD are not entirely clear, the impairment in adult hippocampal neurogenesis has been reported to play a role in AD. To assess the relationship between AD and neurogenesis, we studied APP/PS1/nestin-green fluorescent protein (GFP) triple transgenic mice, a well-characterized mouse model of AD, which express GFP under the control of the nestin promoter. Different ages of AD mice and their wild-type littermates (WT) were used in our study. Immunofluorescent staining showed that neurogenesis occurred mainly in the subgranular zone (SGZ) of the dentate gyrus (DG) and subventricular zone (SVZ) of the lateral ventricles (LVs). The expression of neural stem cells (NSCs) (nestin) and neural precursors such as doublecortin (DCX) and GFAP in AD mice were decreased with age, as well as there being a reduction in 5-bromo-2-deoxyuridine (BrdU)-positive cells, when compared to WT. However, the number of maturate neurons (NeuN) was not significantly different between AD mice and wild-type controls, and NeuN changed only slightly with age. By Golgi-Cox staining, the morphologies of dendrites were observed, and significant differences existed between AD mice and wild-type controls. These results suggest that AD has a far-reaching influence on the regulation of adult hippocampal neurogenesis, leading to a gradual decrease in the generation of neural progenitors (NPCs), and inhibition of the differentiation and maturation of neurons.

Peritumoural neutrophils negatively regulate adaptive immunity via the PD-L1/PD-1 signalling pathway in hepatocellular carcinoma

BACKGROUND

PD-L1 expression on neutrophils contributes to the impaired immune response in infectious disease, but the detailed role of PD-L1 expression on neutrophils in HCC remains unclear.

METHODS

We investigated the phenotype and morphology of neutrophils infiltrated in tumour tissues from both patients with HCC and hepatoma-bearing mice.

RESULTS

We found that neutrophils dominantly infiltrated in the peritumoural region. The neutrophil-to-T cell ratio (NLR) was higher in peritumoural tissue than that in the intratumoural tissue and was negatively correlated with the overall survival of patients with HCC. Infiltrating neutrophils displayed a phenotype of higher frequency of programmed cell death ligand 1 (PD-L1) positive neutrophils. The ratio of PD-L1(+) neutrophils-to-PD-1(+) T cells was higher in peritumoural tissue and better predicted the disease-free survival of patients with HCC. We further confirmed a higher frequency of PD-L1(+) neutrophils and PD-1(+) T cells in hepatoma-bearing mice. Functionally, the PD-L1(+) neutrophils from patients with HCC effectively suppressed the proliferation and activation of T cells, which could be partially reversed by the blockade of PD-L1.

CONCLUSIONS

Our results indicate that the tumour microenvironment induces impaired antitumour immunity via the modulation of PD-L1 expression on tumour infiltrating neutrophils.

Conduction Mechanisms in CVD-Grown Monolayer MoS2 Transistors: From Variable-Range Hopping to Velocity Saturation

We fabricate transistors from chemical vapor deposition-grown monolayer MoS2 crystals and demonstrate excellent current saturation at large drain voltages (Vd). The low-field characteristics of these devices indicate that the electron mobility is likely limited by scattering from charged impurities. The current-voltage characteristics exhibit variable range hopping at low Vd and evidence of velocity saturation at higher Vd. This work confirms the excellent potential of MoS2 as a possible channel-replacement material and highlights the role of multiple transport phenomena in governing its transistor action.

ENaC mediates human extravillous trophblast cell line (HTR8/SVneo) invasion by regulating levels of matrix metalloproteinase 2 (MMP2)

INTRODUCTION

Placenta dysfunction is thought to be the major etiological factor related to preeclampsia. The epithelial sodium channel (ENaC) has been localized in the apical plasma membrane of epithelia, mediating the active reabsorption of sodium in kidney, and be involved in the regulation of blood pressure. In previous studies, we found that the reduced expression of ENaC on placenta in preeclampsia patients. The aim of this study was to determine the role of MMP2 in the ENaC-induced trophoblast cell invasion ability, which is closely related to the occurrence of preeclampsia.

METHODS

Here we checked whether pregnancy related hormones human chorionic gonadotropin (HCG), prolactin and aldosterone could affect ENaC expression in the first trimester extravillous trophoblast cell line (HTR8/SVneo) by RT-PCR and Western blot. Cell invasion was studied by matrigel invasion assay. Tube formation assay was used to investigate the interaction between trophoblast cells and endothelial cells. The effects of ENaC on MMP2 were further determined by RT-PCR, western blot and gelatin zymography.

RESULTS

We demonstrated that HCG, prolactin and aldosterone could up-regulate the expression of αENaC in protein levels. Trophoblast cell invasion ability is stimulated when αENaC was up-regulated by aldosterone, and inhibited when ENaC was down-regulated by amiloride and αENaC specific RNAi (SiENA/ENaC). The interaction between HTR8/SVneo cells and HUVEC cells was enhanced when treated with aldosterone and weakened when treated with amiloride and SiRNA/ENaC. Amiloride and SiRNA/ENaC could inhibit MMP2 expression and activity.

DISSCUTION

Aldosterone induced ENaC activity is important for trophoblast cells invasion. The results also indicate that ENaC could mediate trophoblast cells invasion ability through regulating expression and activity of matrix metalloproteinase-2 (MMP2).

Palladium-catalyzed alkylation of unactivated C(sp3)–H bonds with primary alkyl iodides at room temperature: facile synthesis of β-alkyl α-amino acids

Practical synthesis of β-alkyl α-amino acidsviaC(sp³)–H alkylation at room temperature.

Matrine-induced apoptosis of human nasopharyngeal carcinoma cells via in vitro vascular endothelial growth factor-A/extracellular signal-regulated kinase1/2 pathway inactivation

Matrine, a main active extract from Sophora flavescens Ait, has been demonstrated to exert anticancer effects on various cancer cell lines, such as malignant melanoma, breast cancer, and lung cancer. However, it is currently unclear whether matrine could also elicit an inhibitory effect on growth of nasopharyngeal carcinoma (NPC), let alone the possible molecular mechanisms. Therefore, in a previous study, we investigated matrine-induced proliferation inhibition and apoptosis in NPC cells. It was shown that proliferation of human NPC cells (CNE1 and CNE2) was significantly diminished by matrine in a dose- and time-dependent manner, and apoptosis was induced in both 2 NPC cells, particularly in CNE2 cells. Moreover, the increased apoptosis rate in matrine-treated CNE2 cells confirmed the proapoptotic activity of matrine. We further found that matrine treatment dose- and time-dependently reduced the levels of vascular endothelial growth factor-A (VEGF-A), and inactivated extracellular signal-regulated kinase1/2 (ERK1/2), followed by increased expression of downstream target caspase-3. Overall, we conclude that matrine could induce apoptosis of human NPC cells via VEGF-A/ERK1/2 pathway, which supports the potential use of matrine in clinically treating NPC.

Surface characterization and osteoblast response to a functionally graded hydroxyapatite/fluoro-hydroxyapatite/titanium oxide coating on titanium surface by sol-gel method

OBJECTIVES

To improve efficacy of current titanium and its alloys, in bioactivity and speed of osseointegration, of orthopaedic implants.

MATERIALS AND METHODS

A novel triple-layered functional graded coating, consisting of a porous hydroxyapatite (HA) outermost layer, fluoro-HA (FHA) intermediate layer and titanium oxide (TiO2 ) innermost layer, was created on a titanium substrate by a multistep sol-gel method. X-ray diffraction analysis showed TiO2 anatase and apatite crystallization in the coating.

RESULTS

Morphological analysis performed by scanning electron microscopy showed excellent bonding between coating and substrate, with a thickness of ~2 μm. Scratch testing found favourable adhesion strength of the composite coating. In addition, optical microscope images suggested good biocompatibility. Considering thet in vitro cell response, osteoblasts on the coating exhibited higher cell proliferation and ALP activity compared to pure titanium and HA coating, and demonstrated excellent coating bioactivity.

CONCLUSIONS

Current results indicated that the novel TiO2 /FHA/HA coating has promising clinical applications in orthopaedic and dental implantation.