BET inhibitor JQ1 suppresses cell proliferation via inducing autophagy and activating LKB1/AMPK in bladder cancer cells

AIM

JQ1, a BET bromodomain inhibitor, is a promising therapeutic approach for bladder cancer (BC). Our study aimed to determine whether autophagy is induced by JQ1 and its potential role toward proliferation in BC.

METHODS

Cell proliferation was determined by methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay, cell counting assay, and colony formation assay. Autophagosomes and autolysosomes were observed by transmission electron microscopy and mRFP-EGFP-LC3 fluorescence assay. 3-MA, BAFA1, NH₄ Cl, and siATG5 were used to inhibit autophagy. AMPK siRNA was used to knock down AMPK. T24 xenograft model in mice was chosen to perform in vivo studies. Autophagy markers LC-3B and p62, p-AMPKα, p-ACC, p-ULK1, p-mTOR and p-LKB1 were determined by western blot in vitro studies and by immunohistochemistry (IHC) in vivo specimens.

RESULTS

We found that BC cell proliferation was suppressed by JQ1; moreover, JQ1 induced the accumulation of autophagosomes and autolysosomes, and autophagy flux, and the growth suppression capacity of JQ1 was attenuated by autophagy inhibitors. Furthermore, we found that JQ1 induced the phosphorylation of AMPKα, and AMPKα knockdown attenuated autophagy induction and anti-proliferation effect induced by JQ1 in BC cells, indicating that autophagy induced by JQ1 is dependent on AMPKα. Through endogenous immunoprecipitation analysis, we found that JQ1 dramatically increased the interaction between LKB1 and AMPKα, which may lead to more AMPK activation. Proliferation inhibition, autophagy induction, and LKB1/AMPK activation capacities of JQ1 were further confirmed in vivo.

CONCLUSIONS

Taken together, our results demonstrate that autophagy is induced by JQ1 through activation of LKB1/AMPK pathway, and the autophagy induced by JQ1 positively contributes to the inhibition of BC cell proliferation. These findings provide a novel point of view to understand the mechanism of how targeting BET bromodomain suppress cancer cell growth and suggest that targeting BET bromodomain might be a potential approach to treat BC in the future.

[Evaluation of the intraoperative transesophageal echocardiography for the aortic valve reconstruction]

Objective: To explore the value of the intraoperative transesophageal echocardiography during the aortic valve reconstruction. Methods: The echocardiographic features were retrospectively summarized in 19 patients (male: 15 cases; female: 4 cases; age ranged from 12 to 65 years, mean age: 37.7 years) with aortic valve reconstruction at Beijing Anzhen Hospital between October 2014 and October 2016. Results: The findings of the neo-aortic valve on the transesophageal echocardiography included the slightly thickened and hyperechogenicity of the commission, especially the central coaptation point of the neo-valve. Trace aortic regurgitation was noted in 9 cases after operation, mild aortic regurgitation in 1 case and no aortic regurgitation in 9 cases. The velocity of the aortic valve increased significantly in 2 cases. Compared with pre-operation, the diameter of ascending aorta[(32.7±6.1) mm vs (36.4±6.3) mm, P<0.001]and the inner diameter of left ventricle[(48.3±6.1) mm vs (59.1±7.3) mm, P<0.001]decreased significantly after operation, the coaptation length of aortic valve[(6.6±1.3) mm vs (2.2±0.7) mm, P<0.001]significantly increased than that of pre-operation. The mean immediate velocity after operation (175 cm/s) was slightly higher than that (165 cm/s) of 3-month follow-up after surgery, but with no significant difference (P=0.367). Severe aortic regurgitation was found 15 days after operation in 1 case and 12 months after operation in 2 cases. Conclusion: Intraoperative transesophageal echocardiography is a useful tool to evaluate the result of the aortic valve reconstruction.

[Study on the effect of occupational exposure to glyphosate on blood routine]

Objective: To investigate the effect of glyphosate on blood routine of occupational exposure population. Methods: The workers who were occupationally exposed to glyphosate were selected as exposure group, and administrative staffs who were not exposed to glyphosate were selected as control group. Occupational health examination was conducted on all the subjects, and personal monitoring was applied to detect the concentration of glyphosate in the air of workplace. Time weighted average (TWA) concentration was calculated by the result of determination. Statistical methods were employed to compare the difference of blood routine results between the contact group and the control group, as well as between different posts. Results: 178 glyphosate workers were included in the contact group, and 203 non-contact persons were included in the control group. There was no statistically significant difference in the equilibrium test between the two groups(P>0.05). The abnormal rate of blood routine in the exposure group and the control group were 70.8% and 69.0%, respectively, but the difference was not statistically significant (P>0.05). Compared with the control group, the red blood cell count and platelet distribution width difference (P<0.05) were significant difference. There was no significant difference between different positions (P>0.05). Conclusion: When TWA value is below 9.40 mg/m(3), glyphosate has effect on the results of platelet distribution width and red blood cell count, but has no effect on the abnormal rate of blood routine.

Boron carbide composites with highly aligned graphene nanoplatelets: light-weight and efficient electromagnetic interference shielding materials at high temperatures

B₄C-based ceramic composites containing 0-2 vol% highly aligned graphene nanoplatelets (GNPs) are fabricated. The electromagnetic interference (EMI) shielding properties of the obtained composites are investigated at X-band (8.2-12.4 GHz) frequency range from room-temperature up to 800 °C. All composites exhibit outstanding EMI shielding properties with satisfactory frequency- and thermal-stability. The shielding effectiveness (SE) of GNP/B₄C composites increases monotonically with increasing GNP loading. Superior room-temperature SE close to 40 dB is achieved with only 2 vol% GNPs and high SE around 35 dB still persists at 800 °C. Considering their relatively low density, GNP/B₄C composites possess a high specific shielding effectiveness (SSE) of 16 dB cm³ g^-1 which is among the highest values in reported ceramic-based shielding composites. Especially, the GNP/B₄C composite with 2 vol% GNPs exhibits the highest SSE/t (SSE divided by thickness) values at temperatures above 200 °C for all reported shielding composites, indicating that GNP/B₄C composites belong to the most promising high-temperature shielding composites. The excellent shielding properties of GNP/B₄C composites arise mainly from the high electrical conductivity, high dielectric loss and the multiple reflections by the highly aligned and large-sized GNP layers.

miRNA-31 over-expression improve synovial cells apoptosis induced by RA

OBJECTIVE

The aim of this study was to evaluate the effects and mechanism of miRNA-31 in synovial cells apoptosis induced by RA.

METHODS

The miRNA-31 gene expressions were extracted from synovial tissues of normal and RA patients by RT-PCR and H et E staining. The synovial cells of RA patients were isolated and randomly divided into Control, Blank and miRNA groups. The cell apoptosis of difference groups were measured by flow cytometry; the TNF-α and IL-1β concentrations of difference groups were measured by Elisa assay; TLR4 and NF-κB proteins expressions were measured by WB assay and the correlation between TLR4 and miRNA-31 were evaluated by double luciferase target experiment.

RESULTS

The miRNA-31 gene expression was significantly suppressed in RA tissues (p<0.001); Compared with control group, the cell apoptosis rate of miRNA group was significantly suppressed (p<0.001); TNF-α and IL-1β concentrations were significantly down-regulation in culture fluid (p<0.001, respectively) and TLR4 and NF-κB proteins expressions were significantly depressed (p<0.001, respectively) in miRNA group. By double luciferase target experiment, the TLR4 was a target gene of miRNA-31.

CONCLUSION

miRNA-31 is a key role in synovial cells apoptosis induced by RA (Fig. 7, Ref. 23).

Tyrosinase-doped bioink for 3D bioprinting of living skin constructs

Three-dimensional bioprinting is an emerging technology for fabricating living 3D constructs, and it has shown great promise in tissue engineering. Bioinks are scaffold materials mixed with cells used by 3D bioprinting to form a required cell-laden structure. In this paper, a novel bioink made of gelatin methacrylamide (GelMA) and collagen (Col) doped with tyrosinase (Ty) is presented for the 3D bioprinting of living skin tissues. Ty has the dual function of being an essential bioactive compound in the skin regeneration process and also as an enzyme to facilitate the crosslink of Col and GelMA. Further, enzyme crosslinking together with photocrosslinking can enhance the mechanical strength of the bioink. The experimental results show that the bioink is able to form stable 3D living constructs using the 3D bioprinting process. The cell culture shows that three major cell lines: human melanocytes (HEM), human keratinocytes (HaCat) and human dermal fibroblasts (HDF) exhibit high cell viabilities. The viability of these three cell lines is above 90%. The proliferation and scratching test show that Ty can enhance the proliferation of HEM, inhibit the growth and migration of HDF and not affect HaCat significantly. Animal tests show that the doped bioinks for 3D bioprinting can help form an epidermis and dermis, and thus have high potential as a skin bioink.

Molecular Cloning and Characterization of Ribosomal Protein RPS9 in Echinococcus granulosus

Ribosomal protein S9 (RPS9) is an essential functional gene that participates in DNA repair and developmental regulations. A sequence homolog of RPS9 has been found to be upregulated in the protoscoleces (PSCs) of Echinococcus granulosus treated with artemisinin. However, E. granulosus RPS9 (EgRPS9) has not been identified before. In the present study, the 657-base pair (bp) cDNA encoding EgRPS9 was cloned. Amino acid sequence analysis showed that EgRPS9 was similar to the RSP9 proteins from Schistosoma japonicum (SjRPS9, 86%) and Schistosoma mansoni (SmRPS9, 79%). Phylogenetic tree analysis showed that EgRPS9, SmRPS9, and SjRPS9 were clustered together. We detected the EgRPS9 gene and protein expression in PSCs exposed to artesunate (AS) which displayed a dose-dependent reduction in PSC viability for 24 hr. The results showed that the EgRPS9 ratio of the 10-μM AS-treated ( P < 0.01) and 40-μM AS-treated ( P < 0.05) groups were increased from that of the control group. In addition, the level of reactive oxygen species (ROS) in the AS-treated groups increased in a dose-dependent manner compared to the level in the control group. In conclusion, the expression of EgRPS9 could be induced by ROS and might participate in the oxidative damage-based anti-parasite mechanism of AS treatment.

[Factors influencing antiretroviral therapy adherence among HIV-infected people on antiretroviral therapy in Ili Kazakh Autonomous Prefecture]

Objective: To analyze factors influencing antiretroviral therapy (ART) adherence among human immunodeficiency virus (HIV) patients receiving ART at the town level in Ili Kazakh Autonomous Prefecture (Ili) in May 2015 and to document enhanced ART for acquired immunodeficiency syndrome (AIDS) cases. Methods: A cross-sectional survey was conducted using one-on-one interviews and data collection from the system of AIDS follow-up management in three ART services centers at the town level of Ili. The subjects were HIV-infected individuals, aged 18 years or older, who were receiving ART during the survey. The surveys collected demographic characteristics, information related to ART and status of engaging ART, smoking and drinking behavior, depression, and quality of life. Results: A total of 412 participants completed the survey. The age was (41.1±8.0) years (range, 19-67 years). Approximately 60.9% (251) were male and 39.1% (161) were female. The survey showed that 75.0% (309) of participants were in good adherence and the P(50) (P(25), P(75)) of quality of life was 56.31 (50.55, 59.42). Females demonstrated better adherence to ART (82.6% (n=133)) than males (70.1% (n=76)) (χ(2)=8.16, P=0.005). The compliance rate of participants (78.0% (n=54)) with depression was higher than non-depressed participants (63.5% (n=255)) (χ(2)=7.52, P=0.008). Multivariate logistic regression analyses showed that the probability of good adherence to ART increased with increasing quality of life (OR=1.06, 95%CI:1.02-1.09). Moreover, participants who consumed alcohol or disclosed their HIV infection status to families were less likely to have good adherence to ART (OR=0.26, 95% CI:0.13-0.53 and OR=0.31, 95% CI:0.13-0.72, respectively). Additionally, employed participants were also less likely to have good adherence to ART compared with unemployed participants (OR=0.45, 95% CI:0.21-0.97). Conclusion: HIV/AIDS patients primarily showed good adherence to ART. Factors related to ART adherence included alcohol consumption, informing family of infection, work status, and quality of life.

Impact of isovalent and aliovalent substitution on the mechanical and thermal properties of Gd2Zr2O7

In this study, a density functional theory method is employed to investigate the effects of isovalent and aliovalent substitution of Sm³⁺ on the phase stability, thermo-physical properties and electronic structure of Gd₂Zr₂O₇. It is shown that the isovalent substitution of Sm³⁺ for Gd³⁺ results in the formation of Gd₂Zr₂O₇-Sm₂Zr₂O₇ solid solution, which retains the pyrochlore structure and has slight effects on the elastic moduli, ductility, Debye temperature and band gap of Gd₂Zr₂O₇. As for the aliovalent substitution of Sm³⁺ for Zr⁴⁺ site, a pyrochlore-to-defect fluorite structural transition is induced, and the mechanical, thermal properties and electronic structures are influenced significantly. As compared with the Gd₂Zr₂O₇, the resulted Gd₂Sm_yZr_2-yO₇ compositions have much smaller elastic moduli, better ductility and smaller Debye temperature. Especially, an amount of electrons distribute on the fermi level and they are expected to have larger thermal conductivity than Gd₂Zr₂O₇. This study suggests an alternative way to engineer the thermo-physical properties of Gd₂Zr₂O₇ and will be beneficial for its applications under stress and high temperature.

[Research progress of transoral robotic surgery in oropharyngeal cancer]

When it comes to the treatment of oropharyngeal cancer, the recurrence rate is high after radiotherapy, chemotherapy or open surgery. Transoral robotic surgery is a relatively new surgical therapy in oropharyngeal cancer, which can promote the development of minimally invasive surgery of oropharyngeal cancer. In this study, we reviewed flap reconstruction techniques of transoral robotic surgery, outcomes, contraindications,advantages and disadvantages.

[Application of spontaneous acrosome reaction of sperm in prediction of outcome of in-vitro fertilization and embryo transfer]

OBJECTIVE

To investigate the clinical application of spontaneous acrosome reaction (AR) rate of sperm in predicting the outcome of in-vitro fertilization and embryo transfer (IVF-ET).

METHODS

The spontaneous AR rate of the sperm of patients who underwent IVF-ET treatment in our center during the period from November to December 2014 were studied. The cut-off value from 6% to 12% were set and analyzed its association between the IVF-ET outcomes (including fertility rates, normal fertilization rates and high-quality embryo rates). For those who underwent fresh embryo transplantation, the rates of chemical pregnancy and clinical pregnancy were calculated, and compared the spontaneous AR rates and quantity of acrosomal enzyme according to the pregnancy outcome.

RESULTS

There were 202 patients in this study and the mean spontaneous AR rate was 5.99%±5.18%. For patients with the spontaneous AR rate ≥9% versus <9%, the fertility rate, normal fertilization rate and high-quality embryo rate were 81.33% vs 83.85%, 60.53% vs 60.99%, and 51.10% vs 59.67%, respectively, with statistically significant difference in the high-quality embryo rate (P=0.02). For patients who underwent fresh embryo transplantation, when comparison was made between those with spontaneous AR rate ≥8% and those <8%, the rate of chemical pregnancy and clinical pregnancy were 48.57% (17/35) vs 69.64% (78/112) and 37.14% (13/35) vs 63.39% (71/112), respectively, both with statistically significant difference (P=0.02 and P<0.01). The patients with clinical pregnancy had lower spontaneous AR rate than those without clinical pregnancy (5.41%±3.87% vs 7.40%±6.79%, P=0.04), while the quantity of acrosomal enzyme showed no significant difference [(131.79±68.50) vs (153.62±59.59) μU/10(6,) P=0.06]. Logistic regression analysis demonstrated association between spontaneous AR rates and clinical pregnancy (OR=0.93, 95%CI: 0.87-0.99, P=0.03).

CONCLUSIONS

The spontaneous AR rate of sperm may have clinical significance in predicting the outcome of IVF-ET, as it is reversely correlated with IVF high-quality embryo rate and pregnancy rate. The quantity of acrosomal enzyme may not have significant predictive value for the outcome of IVF.

Molecular cloning and characterization of a C-type lectin in yellow catfish Tachysurus fulvidraco

This study represents the first report of a C-type lectin (ctl) in yellow catfish Tachysurus fulvidraco. The complete sequence of ctl complementary (c)DNA consisted of 685 nucleotides. The open reading frame potentially encoded a protein of 177 amino acids with a calculated molecular mass of c.y 20.204 kDa. The deduced amino-acid sequence contained a signal peptide and a single carbohydrate recognition domain with four cysteine residues and GlnProAsp (QPD) and TrpAsnAsp (WND) motifs. Ctl showed the highest identity (56.0%) to the predicted lactose binding lectin from channel catfish Ictalurus punctatus. Quantitative real-time (qrt)-PCR analysis showed that ctl messenger (m)RNA was constitutively expressed in all examined tissues in normal fish, with high expression in trunk kidney and head kidney, which was increased following Aeromonas hydrophila challenge in a duration-dependent manner. Purified recombinant Ctl (rCtl) from Escherichia coli BL21 was able to bind and agglutinate Gram-positive and Gram-negative bacteria in a calcium-dependent manner. These results suggested that Ctl might be a C-type lectin of T. fulvidraco involved in innate immune responses as receptors (PRR).

[Focal periphyseal edema zone on MRI and clinical significance of the adolescent knee]

OBJECTIVE

To investigate the MR image characteristics and clinical significance of focal periphyseal edema (FOPE) zone of the adolescent knee which was with or without trauma history, and provide the basis for the correct diagnosis and treatment.

METHOD

A total of 12 patients (9 boys, age range 12-16 years, average age 14 years old, 3 girls, age range 12-15 years, average age 13 years )who had pain of the knee without the traumatic history and 16 patients (12 boys, age range 10-15 years, average age 14 years; 4 girls, age range 11-13 years, average age 12 years) who were painful in the knee after trauma were included in this study. The knee MR examinations were performed in all the patients. The characteristics of MRI between painful knee without trauma and painful knee after trauma were compared and analyzed, and the average vertical distances from the farthest of the edema area to the epiphyseal plate were measured. The vertical distances were measured respectively in sagittal view and coronal view in PD-FS and in sagittal view in T1WI, and the average for the three were calculated. At last, the images with the results of operation or follow-up examinations were compared and confirmed by double blind method.

RESULTS

The MRI characteristics of FOPE zone in the 12 adolescent who complained painful knee but had no trauma showed low signal intensity in T1WI and high signal intensity in PD-FS. The edema centered at the physis and extended into both the adjacent epiphysis and metaphysic.In addition, it shaped like patches and thread, and edema range(14.5±6.6)mm.The MRI findings of the 16 adolescent had pain of the knee after injury characterized by a wide range of low T1WI signal intensity and increased PD-FS signal intensity involving the articular surface of the epiphysis.The range of edema was (26.2±8.8)mm.There was statistically significant difference between non-traumatic edema and the edema caused by trauma (t=4.346, P<0.05).

CONCLUSION

A FOPE zone of the adolescent knee is likely to be related to pain in the adolescent growth period and physiologic physeal fusion, and should not be mistaken for an abnormality, while the larger range of edema surrounding the epiphyseal plate may be associated with the trauma of the knee.

Low temperature H2S removal with 3-D structural mesoporous molecular sieves supported ZnO from gas stream

A series of 3-dimensional (3-D) structural mesoporous silica materials, SBA-16, MCM-48 and KIT-6, was synthesized and supported with different ZnO loadings (10, 20, 30, and 40 wt%) by the incipient wetness method to evaluate the performances on H2S removal at room temperature. These materials were characterized by N2 adsorption, XRD, and TEM to investigate their textural properties. All the ZnO-loaded adsorbents exhibited the H2S removal capacity of bellow 0.1 ppmv. With the best ZnO loading percentage of 30 wt% on MCM-48 and KIT-6, 20 wt% on SBA-16 according to the results of breakthrough test, further increasing ZnO loading caused the decrease of the adsorption capacity due to the agglomeration of ZnO. Besides, the H2S adsorption capacities of the supports materials varied in the order of KIT-6>MCM-48>SBA-16, which was influenced primarily by their pore volume and pore size. With the largest pores in these 3-D arrangement materials, KIT-6 showed the best performance of supported material for ZnO, due to its retained superior physical properties as well as large pore diameter to allow faster gas-solid interaction and huge pore volume to disperse ZnO on the surface of it.

Ab initio molecular dynamics simulation of the effects of stacking faults on the radiation response of 3C-SiC

In this study, an ab initio molecular dynamics method is employed to investigate how the existence of stacking faults (SFs) influences the response of SiC to low energy irradiation. It reveals that the C and Si atoms around the SFs are generally more difficult to be displaced than those in unfaulted SiC, and the corresponding threshold displacement energies for them are generally larger, indicative of enhanced radiation tolerance caused by the introduction of SFs, which agrees well with the recent experiment. As compared with the unfaulted state, more localized point defects are generated in faulted SiC. Also, the efficiency of damage production for Si recoils is generally higher than that of C recoils. The calculated potential energy increases for defect generation in SiC with intrinsic and extrinsic SFs are found to be higher than those in unfaulted SiC, due to the stronger screen-Coulomb interaction between the PKA and its neighbors. The presented results provide a fundamental insight into the underlying mechanism of displacement events in faulted SiC and will help to advance the understanding of the radiation response of SiC with and without SFs.

In situ growth of carbon nanotubes on Ni/MgO: a facile preparation of efficient catalysts for the production of synthetic natural gas from syngas

Ni/MgO-CNTs catalysts are prepared by in situ chemical vapor deposition growth of CNTs on Ni/MgO. These catalysts exhibit an improved performance for the production of synthetic natural gas from syngas, which is attributed to the formation of highly catalytic active interfaces among Ni, CNTs and MgO.

Regulators of G-protein signaling 9 genetic variations in Chinese subjects with schizophrenia

To identify single-nucleotide polymorphisms that contribute to the genetic susceptibility to schizophrenia, we examined the potential association between schizophrenia and 9 single nucleotide polymorphisms (rs1530351, rs4791230, rs2869577, rs8077696, rs8070231, rs2292592, rs9916525, rs1122079, and rs4790953) in the G-protein signaling 9 gene. The participants included 395 schizophrenia subjects and 400 healthy controls. The selected single nucleotide polymorphisms were genotyped using mass spectrometry techniques. The allelic or genotypic frequencies of the rs4791230 (promoter region) polymorphisms in subjects with schizophrenia were significantly different from those in healthy controls. The subjects with schizophrenia had a significantly higher frequency of the G allele (P = 0.030, odds ratio = 1.589, 95% confidence interval = 1.042-2.422) of rs4791230. Strong linkage disequilibrium was observed in 4 blocks (D' > 0.9). Significantly fewer T-A (rs1530351-rs4791230) haplotypes (P = 0.029) were found in subjects with schizophrenia. These findings suggest a role of G-protein signaling 9 polymorphisms in schizophrenia among Han Chinese and may be informative for future genetic or neurobiological studies on schizophrenia.

Supplementation dietary zinc levels on growth performance, carcass traits, and intramuscular fat deposition in weaned piglets

This study was conducted to estimate dietary zinc (Zn) levels on growth performance, carcass traits, and intramuscular fat (IMF) deposition in weaned piglets. Sixty piglets were randomly divided into five groups, as follows: control (basal diet), Zn250, Zn380, Zn570, and Zn760 with supplementation of 250, 380, 570, and 760 mg Zn/kg of the basal diet, respectively. The final weight, average daily gain (ADG), gain/feed (G/F), lean meat percentage, fat meat percentage, lean eye area, backfat thickness, and IMF content were dose-dependently increased in all groups of Zn treatment. The serum total triglycerides (TG) and free fatty acid (FFA) were significantly higher in all Zn treatments than in the control. The enzyme activities of lipoprotein lipase (LPL), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC) were markedly higher, while enzyme activities of hormone-sensitive lipase (HSL) and carnitine palmitoyltransferase-1 (CPT-1) were significantly lower in all Zn treatments than in the control. The messenger RNA (mRNA) levels of sterol regulatory element-binding protein 1 (SREBP-1), stearoyl-CoA desaturase (SCD), FAS, ACC, peroxisome proliferator-activated receptor γ (PPARγ), LPL, and adipocyte fatty acid-binding protein (A-FABP) were significantly higher, while the mRNA levels of CPT-1 and HSL were significantly lower in all Zn treatments compared with the control. These results indicated that high levels of Zn increased IMF accumulation by up-regulating intramuscular lipogenic and fatty acid transport gene expression and enzyme activities while down-regulating lipolytic gene expression and enzyme activities.

Record-high and robust 17.125 Gb/s gross-rate over 25 km SSMF transmissions of real-time dual-band optical OFDM signals directly modulated by 1 GHz RSOAs

Aggregated 17.125 Gb/s real-time end-to-end dual-band optical OFDM (OOFDM) transmissions over 25 km SSMF IMDD systems with 7 dB receiver sensitivity improvements are experimentally demonstrated, for the first time, by utilizing low-cost transceiver components such as directly modulated 1GHz RSOAs and DACs/ADCs operating at sampling speeds as low as 4GS/s. The demonstrated OOFDM transceivers have both strong adaptability and sufficiently large passband carrier frequency tunability, which enable full use of highly dynamic spectral characteristics of the transmission systems. This results in the achievements of not only excellent performance robustness to variations in system operating conditions but also significantly relaxed requirements on RSOA small-signal modulation bandwidth. It is shown that the aforementioned transmission capacity only varies by <23% over a RSOA-injected optical power variation range as large as 20dB, and that the 1 GHz RSOAs can support successful transmissions of adaptively modulated OOFDM signals having bandwidths of 8.5 GHz. By taking into account the adopted 25% cyclic prefix and a typical 7.3% FEC overhead, the demonstrated real-time OOFDM transmission systems are capable of conveying 11.6 Gb/s user data.

Electrical tuning of transport properties of topological insulator ultrathin films

Considering that topological insulator (TI) ultrathin films (UTFs) provide an ideal platform for the transport measurement of topologically protected surface states, we have investigated the transport properties of the three-dimensional (3D) TI UTFs through an array of potential barriers. The 3D TI UTF was considered to be thin enough (5 nm) that the top and bottom surface states of the UTF can hybridize to create an energy gap at the Dirac point, which results in a hyperbola-like energy dispersion. It was found that the Klein tunneling effect disappears due to the interaction between the top and bottom surface states. By tuning the barrier strength or the incident energy, three kinds of transport processes can be realized, and the conditions of the transport processes were determined. The oscillatory characters of the transmission (conductance) spectra without a decaying envelope are due to the novel surface states of TIs, which are quite different from that observed for a conventional two-dimensional electron gas. For the structure consisting of two anti-parallel potential barriers, the conductance spectra exhibit a perfect on/off switching effect by tuning the barrier strength, which is favorable for electrically controllable device applications. In the case of a superlattice (SL) structure, due to the mini-gaps induced by the SL geometry, some additional resonant peaks and valleys can be observed in the transmission spectra, and similar characters are also reflected in the conductance spectra. Owing to the Dirac characters of the charge carriers therein, the transmission (conductance) spectra never decay with increasing barrier strength, which is distinguished from that observed for semiconductor SLs. These findings were not only meaningful for understanding the basic physical processes in the transport of TIs, but also useful for developing nanoscaled TI-based devices.

Metabolic syndrome and risk for ED: a meta-analysis

There are many recent observational studies on metabolic syndrome (MS) and the risk for ED, and it is still inconclusive whether MS increases the risk for ED. This meta-analysis aims to detect a relationship between MS and ED. We identified eligible studies by searching PubMed, Embase and the Cochrane Library for articles published before August 2013. Adjusted relative risks (RR) with 95% confidence interval (CI) were calculated using random-effects or fixed-effects models. A total of 10 studies involving 4092 participants were included in the meta-analysis. MS was associated with an increased incidence of ED (RR=1.60, 95% CI=1.27-2.02, P<0.001), with significant evidence of heterogeneity among these studies (P for heterogeneity <0.001, I(2)=92.9%). The subgroup and sensitivity analyses confirmed the stability of the results and no publication bias was detected. The present meta-analysis suggests that MS is significantly associated with the risk for ED. Large-scale and well-designed prospective studies are required to further investigate the association between MS and risk for ED.

Robust real-time 15.125 Gb/s adaptive optical OFDM transmissions over 100 m OM2 MMFs utilizing directly modulated VCSELs subject to optical injection locking

Optical injection locking (OIL) is an effective approach for significantly enhancing the modulation bandwidths of VCSELs. The frequency responses of OIL-VCSELs are, however, very sensitive to the applied OIL conditions. This brings about strong difficulties in practically utilizing the OIL-enhanced modulation bandwidths to achieve highly robust transmission performances of directly modulated OIL-VCSEL-based multi-mode fibre (MMF) links for cost-sensitive application scenarios such as data-centers. In this paper, directly modulated OIL-VCSEL-based real-time dual-band optical OFDM (OOFDM) transceivers with tunability in both the electrical and optical domains are experimentally demonstrated, for the first time, utilizing DACs/ADCs at sampling speeds as low as 4GS/s. The transceivers can support 15.125 Gb/s adaptive OOFDM transmissions over 100 m OM2 MMF links based on intensity modulation and direct detection. More importantly, the adaptability and tunability of the demonstrated transceivers enable the achievement of excellent robustness of the aggregated OOFDM transmission capacity to OIL condition variations. It is shown that, over a large diversity of OIL conditions that give rise to significantly different system frequency responses, the aggregated OOFDM transmission capacity only vary by <11% in the aforementioned transmission link.

Superficial parotid lobe-sparing delineation approach: a better method of dose optimization to protect the parotid gland in intensity-modulated radiotherapy for nasopharyngeal carcinoma

PURPOSE

We used a superficial parotid lobe-sparing delineation approach for dose optimization with better protection for the parotid glands in intensity-modulated radiotherapy (imrt) for nasopharyngeal carcinoma (npc) patients.

METHODS

Compared with traditional contouring of the entire parotid glands as organs at risk (oars) in imrt for npc, we used a superficial parotid lobe-sparing delineation approach of contouring the superficial parotid lobes as oars. Changes in dose to the parotid glands, the targets, and other oars were evaluated.

RESULTS

The mean dose to the parotid glands overall decreased by more than 4 Gy in the test plans. Impressively, the mean dose to the superficial parotid lobes in the test plans was not more than 30 Gy, regardless of clinical stage. In T1-3 npc patients, the dose distributions for targets were not significantly different in the control plans and the test plans. However, for some T4 patients, the dose distributions for targets and brainstem in the test plans could not meet clinical requirements.

CONCLUSIONS

The superficial parotid lobe-sparing delineation approach can significantly lower the mean dose to the entire parotid and to the superficial parotid lobe in T1-3 npc patients, which would be expected to result in less xerostomia and better quality of life for those patients.