TiO_(2)直接还原制备超低氧钛

提出在MgCl_(2)−KCl−YCl_(3)熔盐中,通过熔盐电解产生Mg直接还原TiO_(2)制备低氧钛。绘制Mg−Ti−O三元相图和电位−氧势(φ−pO^(2)−)图,表明镁还原TiO_(2)制备低氧钛是可行的。在MgCl_(2)−YCl_(3)和MgCl_(2)−YCl_(3)−KCl熔盐中,不同温度和施加电压条件下,开展熔盐电解−镁热还原TiO_(2)实验研究,结果表明:借助YOCl沉淀及CO_(x)同步生成,将还原和脱氧产物O^(2)−快速脱除,在1073~1173 K、施加电压2.5~3.1 V的条件下,通过电化学还原可以将TiO_(2)还原为高氧钛(Ti6O)。在温度为1173 K的MgCl_(2)−YCl_(3)熔盐中,开展不同施加电压下的高氧钛电化学脱氧实验。此外,还观察到有可能将高氧钛的氧含量可从1200×10^(−6)降至100×10^(−6)以下。

Optical design of the time-resolved ARPES beamline of the new material spectroscopy experimental station for the update of CAEP THz-FEL facility

The Chinese Academy of Engineering Physics Terahertz Free Electron Laser Facility(CAEP THz FEL,CTFEL)is the only high-average power free electron laser terahertz source based on superconducting accelerators in China.The update of the CTFEL is now undergoing and will expand the frequency range from 0.1–4.2 THz to 0.1–125 THz.Two experimental stations for material spectroscopy and biomedicine will be built.A high harmonic generation(HHG)lightsource based beamline at the material spectroscopy experimental station for time-resolved angle-resolved photoemission spectroscopy(ARPES)research will be constructed and the optical design is presented.The HHG lightsource covers the extreme ultraviolet(XUV)photon energy range of 20–50 eV.A Czerny–Turner monochromator with two plane gratings worked in conical diffraction configuration is employed to maintain the transmission efficiency and preserve the pulse time duration.The calculated beamline transmission efficiency is better than 5%in the whole photon energy range.To our knowledge,this is the first time in China to combine THz-infrared FEL with HHG light source,and this experimental station will be a powerful and effective instrument that will give new research opportunities in the future for users doing research on the dynamic evolution of the excited electron band structure of a material’s surface.

Preparation of low-oxygen titanium powder by magnesiothermic reduction of TiO2 assisted by MgCl_(2)−HoCl_(3) molten salt

To reduce the production cost of titanium,a new method for direct preparation of low-oxygen titanium powder by the magnesiothermic reduction of TiO_(2) with the assistance of a MgCl_(2)−HoCl_(3) molten salt was proposed.Thermodynamic calculations showed that the magnesiothermic reduction of TiO_(2) was feasible.However,hindrance of the reduction reaction by the reduction by-product of MgO resulted in a considerably high O concentration in the titanium powder.The addition of HoCl_(3) to the system significantly reduces the activity of MgO to produce low-oxygen titanium powder.Thermochemical deoxidation and reduction experiments were conducted with MgCl_(2)−HoCl_(3) molten salt in the temperature range of 1023−1273 K.The results showed that titanium powder with oxygen concentration(mass fraction)below 5.00×10^(-4) can be prepared at the Mg−MgCl_(2)−HoOCl−HoCl_(3) equilibrium.

高清胃镜观察胃黏膜形态预测幽门螺杆菌感染的探索

目的通过高清胃镜观察、归纳幽门螺杆菌(Hp)感染时胃黏膜形态改变以预测Hp感染结果,从而探讨高清胃镜直接诊断Hp感染的临床价值。方法纳入2016年10月-2017年1月在深圳市龙岗区第二人民医院同时进行胃镜检查和13C-尿素呼气试验的连续性500例受检者,以高清胃镜在白光下直接观察胃黏膜形态,根据所见形态特点预测是否存在Hp感染,并与13C-尿素呼气试验结果进行比对,比较两者结果符合率。结果胃体、胃底黏膜充血或出血;胃黏膜水肿;胃底、胃体黏膜可见较多黏液;中度以上黏膜萎缩;黏膜肠上皮化生;十二指肠球部溃疡可能成为胃镜预测Hp感染阳性的特征点。胃体可见规则集合静脉(RAC);胃黏膜有光泽,无萎缩;胃底或胃体息肉;胃窦或胃体小弯的放射性充血可能成为胃镜预测Hp感染阴性的特征点。胃镜预测Hp感染的敏感性为90.1%,特异性为70.4%;阳性预测值为71.0%,阴性预测值为89.9%,总体符合率79.2%。结论高清胃镜直接观察胃黏膜形态表现可有效预测Hp感染情况,可在临床上进一步推广验证。

Seroepidemiology of hepatitis B virus infection and impact of vaccination

AIM: To investigate hepatitis B virus(HBV) prevalence in the general population in China.METHODS: A total of 148931 individuals were investigated by multistage random sampling in Eastern China. Data were collected on demographics and hepatitis B vaccination history, and serum was tested for hepatitis B surface antigen(HBs Ag) by ELISA. RESULTS: A total of 11469 participants(7.70%, 95%CI: 7.57%-7.84%) were positive for HBs Ag. HBs Ag prevalence was 0.77% among children < 5 years old but increased progressively from adolescents(1.40%-2.55%) to adults(5.69%-11.22%). A decrease in HBs Ag prevalence was strongly associated with vaccination and familial history of HBV among both children and adult groups. Meanwhile, HBs Ag risk in adults was associated with invasive testing and sharing needles. The HBV immunization rate among participants aged < 20 years was 93.30%(95%CI: 93.01%-93.58%). Significant difference in HBs Ag prevalence appeared between vaccinated and unvaccinated participants(3.59% vs 10.22%). CONCLUSION: Although the national goal of HBs Ag prevalence < 1% among children < 5 years old has been reached, immunization programs should be maintained to prevent resurgence.

Epidemiology of hepatitis C virus in Iran

In Iran,the prevalence of hepatitis C virus(HCV) infection is relatively low according to the populationbased epidemiological studies. However,the epidemiology of HCV is changing and the rate of HCV infection is increasing due to the growth in the number of injecting drug users in the society. In addition,a shift has occurred in the distribution pattern of HCV genotypes among HCV-infected patients in Iran. Genotype 1a is the most prevalent genotype in Iran,but in recent years,an increase in the frequency of 3a and a decrease in 1a and 1b have been reported. These variations in the epidemiology of HCV reflect differences in the routes of transmission,status of public health,lifestyles,and risk factors in different groups and geographic regions of Iran. Health policy makers should consider these differences to establish better strategies for control and prevention of HCV infection. Therefore,this review was conducted to present a clear view regarding the current epidemiology of HCV infection in Iran.

Application of Terahertz Technology for Neuroscience

Brain is the most complex organ of human beings. The complete understanding of human brains＇ functions is an ongoing challenge for neuroscience. Although there are many techniques used for brain research, neuroscientists, physicists, and engineers are still exploring other access of research for applications. Terahertz （THz） spectroscopy and imaging may create such a space for brain research. THz spectroscopic technique, which is a novel medical imaging modality, attracts attention of biomedical applications due to its unique features including non-invasive, non-ionizing, and high sensitivity to biomolecules and tissues. In this article, we introduce our recent investigations on neuroscience using THz techniques, meanwhile, introduce other＇s work in this field. Our and others＇ investigations indicate that the THz spectroscopy and imaging technique can be useful for diagnosing brain tumors and neurodegenerative diseases. THz spectroscopy and imaging has the potential to become real-time in vivo diagnostic methods.

A systematic review and meta-analysis for platelet-rich plasma in treatment of knee osteoarthritis

Objective:Knee osteoarthritis(KOA)is a common chronic joint disease that usually occurs in older people,and injuries articular cartilage and cartilage proliferation. Studies have shown that platelet-rich plasma(PRP),as one of non-surgical treatments,is used to alleviate the symptoms of patients with KOA,becoming popular with doctors. In this study,the purpose was to investigate the effects of platelet-rich plasma on the level of pain and function in patients with KOA. Methods:The Pubmed,Cochrane Library,Embase,and Medline were investigated from 2005 through May 2020. All randomized double-blind controlled trials on the effect of PRP injections for KOA were included. Outcome indicators included the Western Ontario and McMaster Universities Arthritis Index(WOMAC)and the Knee Osteoarthritis Outcome Score(KOOS)for function,the visual analogue scale(VAS)for pain,and adverse events(AEs). Review Manager 5.3 was used to calculate these outcome indicators. Results:In this study,(1)Seven studies met the eligibility criteria,including 250 patients in the experiment(PRP)group and 230 patients in the control(no PRP)group.(2)Meta-analysis results showed that the WOMAC scores were differed significantly between the PRP and no PRP groups at the 6 months follow-up(MD=9.63,95%CI:3.29 to 15.96,P=0.003),and 12 months follow-up(MD=3.85,95%CI:2.66 to 5.04,P<0.000 01)(P<0.05). In a comparison of KOOS function scores at the 6 months follow-up,PRP improved knee function scores more than no PRP(MD=8.63,95%CI:0.85 to 16.42,P=0.03)(P<0.05). PRP injections reduced pain more effectively than no PRP injections in patients with KOA at 3,6 months of follow-up,and the VAS pain score showed a significant difference(SMD=0.88,95%CI:0.13 to 1.62,P=0.02)(SMD=0.85,95%CI:0.11 to 1.59,P=0.002)(P<0.05). However,adverse events(AEs)were all not significantly different(RR=0.96,95%CI:0.65 to 1.40,P=0.82)(P>0.05).(3)Results showed that PRP has significant advantages in pain relief and functional improvement. Conclusion:In improving knee function and relieving pain,PRP showed superiority to other non-surgical treatments in long-term follow-up from well-designed double-blind trials. Due to the limited quality and data,more high-quality multi-center studies are required.

Analysis of influencing factors of clinical effect of TCM treatment for degenerative lumbar spondylolisthesis

Objective:To explore the related factors that may affect the efficacy of traditional Chinese medicine in treating degenerative lumbar spondylolisthesis.Methods:A total of 535 patients with DLS who were treated in Wangjing Hospital of China Academy of Chinese Medical Sciences and other hospitals from June 2011 to October 2014 were selected.The central random system was used to randomly divide the treatment group and control group.This study included 267 patients in the treatment group using the traditional Chinese medicine program((lumbar spine reduction and lumbar spine rehabilitation),36 cases of severely missing data were excluded,and a total of 231 DLS patients were included.Observation indicators were selected using the Visual Analog Scale(VAS)and the Japanese Orthopaedic Association(JOA)for the evaluation of lumbar vertebral disorders.The clinical efficacy was evaluated using the JOA lumbar pain curative effect evaluation standard[7].[(Joa score after treatment-JOA score before treatment]/(out of 29 points-JOA score before treatment)]×100%.The JOA score and the change of the efficacy index of the patients were observed.According to the JOA efficacy index after the treatment,it was divided into significant effect(≥50%)and poor effect(<50%).Single-factor screening and multi-factor Logistic regression analysis were used.Gender,age,course of disease,BMI index,slip-off segment,slip-off direction,back pain VAS score,total JOA score,back pain-score,lower limb pain and numbness-score,walking ability-score,straight leg elevation test-score,Feeling-scoring,muscle strength-scoring,supine turn-scoring,standing action-scoring,washing action-scoring,standing posture and continuous standing-scoring,long sedentary-scoring,weight lifting and holding-scoring,walking-scoring 2.Bladder function-scores were assigned to logistic regression models for univariate analysis,and meaningful independent variables were screened for multivariate logistic regression.Results:No serious adverse reactions occurred in the patients included in this study.According to the comparison of JOA scores before and after treatment,the results of the index of efficacy index showed that the effective rate of DLS in this project was 96.6%,and a significant effect of 77.6%was achieved.Univariate Logistic regression analysis showed that the duration of disease,supine turn-scoring,washing action-scoring,prolonged sedentary-scoring,weight lifting and keeping-scoring had statistically significant effects on the inclusion of patients with significant efficacy(P<0.05);single factor logistic regression analysis of total score of JOA score before treatment was not statistically significant(P=0.215),but because it is important for evaluating the patient's condition,it was included in multifactor logistic regression analysis at the same time.Course of onset,supine turn-scoring,washing action-scoring,prolonged sedentary-scoring,weight lifting and holding-scoring,JOA score before treatment.Six independent variables were substituted into the two-class logistic regression model for multivariate analysis..Multivariate logistic regression analysis showed that the effects of total JOA score and supine turn-scoring before treatment on the efficacy of patients were statistically significant(P<0.05).There are many factors influencing the efficacy of traditional Chinese medicine treatment of DLS,and the probability of obtaining a significant effect for each additional point of JOA score and supine turn-score before treatment increases by 1.167 and 0.410 times,respectively.Conclusion:The clinical application of lumbar spine reduction combined with lumbar rehabilitation exercises in patients with degenerative lumbar spondylolisthesis with a higher total JOA score or a lower limit of supine turning can achieve better clinical results.This finding has certain guiding significance for the clinical application of this therapy in the treatment of DLS,and is beneficial to improving patient satisfaction and clinical effectiveness.

Research progress on therapeutic mechanism of spinal diseases caused by nerve root compression

Manipulation of traditional Chinese medicine(TCM), which has been proved effective in clinical already, has been used widely in clinical treatment as a significant method to treat the Orthopedics degenerative diseases. At present, plenty of researches on intervention mechanism of manipulation have been carried out, but it has not been completely elucidated. This paper attempts to sort out relevant articles about manipulation therapy of the spinal disease caused by nerve root compressed systematically and classify and expound some confirmed mechanism of these therapy, so as to help other clinical doctors when they select the treatment plan and promote the standardization process of manipulation therapy.

Effects of kidney-tonifying and blood circulation-promoting recipes and platelet-rich plasma on the activity and expression of type I collagen

Objective:To observe the effects of kidney-tonifying and blood circulation-promoting recipes and platelet-rich plasma(PRP)on the activity and expression of type I collagen in co-culture system.Methods:The subcutaneous adipose tissue and degenerative nucleus pulposus tissue of patients with nucleus pulposus removal under lumbar intervertebral disc degeneration were isolated and cultured by multiple enzyme digestion methods to establish a co-culture system of ADSCs/NPCs.Patients with lumbar intervertebral disc degeneration were enrolled for 2 weeks.The venous blood was taken 50mL before the first dose and one hour after the last dose.Platelet-rich plasma was prepared by secondary centrifugation and cultured with different plasma.The experiment was divided into five groups:platelet-rich plasma group(PRP),platelet-poor plasma group(PPP),drug-rich platelet-rich plasma group(M-PRP)and drug-poor platelet plasma group(M-PPP),fetal bovine serum group(FBS).The morphological changes of the cells in each group were observed under an inverted microscope.The changes of type I collagen activity were detected by immunofluorescence assay.The expression of CCOL1A1 gene was detected by RT-PCR two weeks after the intervention.Results:In this study,the results of kidney-tonifying and blood circulation-promoting recipes and PRP group intervention were shown.The results of the group intervention showed that the M-PRP group and the PRP group had clearer cell contours and better refractive index than the other groups,and there was no significant difference between the two groups.The results of immunofluorescence staining showed that the number of cells in PRP group and M-PRP group was higher,but the staining intensity of single cells was significantly lower than that in FBS group.RT-PCR results showed that the expression of COL1A1 mRNA in PPP group,PRP group,M-PRP group and M-PPP group was significantly down-regulated(P<0.05),respectively:0.343±0.040,0.294±0.018,0.310±0.022,0.430±0.020.Conclusions:Kidney-tonifying and blood circulation-promoting recipes combined with platelet-rich plasma can decrease the activity and exhibit a tendency to inhibit the expression of type I collagen.

An overview of the latest international guidelines on evidence-based knee osteoarthritis

Knee osteoarthritis(KOA)is the highest incidence of osteoarthritis,which seriously affects the quality of life of patients.In order to update the understanding of the disease,clear diagnostic criteria and appropriate treatment were proposed.In 2018 and 2019,the European Society for Clinical and Economic Aspects of Osteoporosis,Osteoarthritis and Musculoskeletal Diseases(ESCEO),the Association of the Scientific Medical Societies in Germany(AWMF)and Brazil successively formulated guidelines for knee osteoarthritis,which determined different guidance suggestions through systematic evaluation of a large number of literatures and evidence-based medical evidence analysis.This paper compares and interprets the guidelines,and discusses them according to the actual situation of our country for the reference of clinicians.

On the prevention and treatment of cervical spondylosis^1

Cervical spondylosis is a kind of frequently occurring and refractory disease with high recurrence rate and tends to be younger. It has become a multiple refractory disease at home and abroad, and its mechanism research and clinical diagnosis and treatment are still controversial. This article will discuss the etiology, pathogenesis, mechanism and treatment of cervical spondylosis from ancient Chinese medicine and modern western medicine, and focus on the research progress of modern prevention and treatment of cervical spondylosis, in order to provide reference for modern clinical treatment of cervical spondylosis.

Effects of Kidney-tonifying and Blood Circulation-promoting Recipes and PRP on the Activity and Expression of Type I Collagen

Objective:To observe the effects of kidney-tonifying and blood circulation-promoting recipes and platelet-rich plasma (PRP) on the activity and expression of type I collagen in co-culture system.Methods:The subcutaneous adipose tissue and degenerative nucleus pulposus tissue of patients with nucleus pulposus removal under lumbar intervertebral disc degeneration were isolated and cultured by multiple enzyme digestion methods to establish a co-culture system of ADSCs/NPCs. Patients with lumbar intervertebral disc degeneration were enrolled for 2 weeks.The venous blood was taken 50mL before the first dose and one hour after the last dose. Platelet-rich plasma was prepared by secondary centrifugation and cultured with different plasma. The experiment was divided into five groups: platelet-rich plasma group (PRP), platelet-poor plasma group (PPP), drug-rich platelet-rich plasma group (M-PRP) and drug-poor platelet plasma group (M-PPP), fetal bovine serum group (FBS). The morphological changes of the cells in each group were observed under an inverted microscope. The changes of type I collagen activity were detected by immunofluorescence assay. The expression of CCOL1A1 gene was detected by RT-PCR two weeks after the intervention.Results:In this study, the results of kidney-tonifying and blood circulation-promoting recipes and PRP group intervention were shown. The results of the group intervention showed that the M-PRP group and the PRP group had clearer cell contours and better refractive index than the other groups, and there was no significant difference between the two groups. The results of immunofluorescence staining showed that the number of cells in PRP group and M-PRP group was higher, but the staining intensity of single cells was significantly lower than that in FBS group. RT-PCR results showed that the expression of COL1A1 mRNA in PPP group, PRP group, M-PRP group and M-PPP group was significantly down-regulated (P<0.05), respectively: 0.343±0.040, 0.294±0.018, 0.310±0.022, 0.430±0.020.Conclusion:Kidney-tonifying and blood circulation-promoting recipes combined with platelet-rich plasma can decrease the activity and exhibit a tendency to inhibit the expression of type I collagen.

Evaluation of the quality of randomized controlled trials on exercise for cervical radiculopathy

Objective:To review and evaluate the quality of the randomized controlled trials of exercise for the treatment of cervical radiculopathy with the present internationally recognized CONSORT statement, which provides reference and basis for the improvement of clinical research on exercise for intervening cervical radiculopathy in the future.Methods: A computer-based search of large domestic databases, including CNKI, Wanfang database and VIP database screened out literature that meet the requirements and used CONSORT statement for quality assessment.Results: According to the prescribed inclusion and exclusion criteria, 30 articles were retrieved in accordance with the standard. No literature was referred to the randomized controlled trial, 2 documents clearly defined the type of test design, 1 documents carried out the calculation of sample size, 13 documents clearly randomly assigned, 1 literature implemented the blind method, in the 7 literature, baseline information was shown in tabular form, and no reference was made to trial registration, trial protocol and funding.Conclusion:There are some aspects of randomized controlled trials on exercise for the treatment of cervical radiculopathy. However, there are some aspects that need to be improved. In the future randomized controlled trial report, the CONSORT statement should be highly valued and carefully considered to improve the accuracy and credibility of the research.

Isthmic spondylolisthesis: Interpretation of NASS guidelines for evidence-based medicine

Isthmic spondylolisthesis in adults is a common clinical disease that causes lower back pain. In order to provide the best and effective diagnosis and treatment plan, in 2014, the North American Spine Association (NASS) formulated the guidelines for the diagnosis and treatment of isthmic spondylolisthesis in adult (hereinafter referred to as the guideline). Through the systematic review of literature, evidence-based medical evidence analysis was conducted to identify different recommended intensities, to discuss the clinical diagnosis and treatment plan mainly from two aspects of diagnosis and treatment. This article gives a brief explanation of the guidelines and discusses them in combination with the clinical practice in China, so as to provide a reference for clinicians.

Effect of Static Load on the Nucleus Pulposus of Rabbit Intervertebral Disc Motion Segment in Ex vivo Organ Culture

Background：The development of mechanically active culture systems helps increase the understanding of the role of mechanical stress in intervertebral disc （IVD） degeneration.Motion segment cultures allow for preservation of the native IVD structure,and adjacent vertebral bodies facilitate the application and control of mechanical loads.The purpose of this study was to establish loading and organ culture methods for rabbit IVD motion segments to study the effect of static load on the whole disc organ.Methods：IVD motion segments were harvested from rabbit lumbar spines and cultured in no-loading 6-well plates （control conditions） or custom-made apparatuses under a constant,compressive load （3 kg,0.5 MPa） for up to 14 days.Tissue integrity,matrix synthesis,and the matrix gene expression profile were assessed after 3,7,and 14 days of culturing and compared with those of fresh tissues.Results：The results showed that ex vivo culturing of motion segments preserved tissue integrity under no-loading conditions for 14 days whereas the static load gradually destroyed the morphology after 3 days.Proteoglycan contents were decreased under both conditions,with a more obvious decrease under static load,and proteoglycan gene expression was also downregulated.However,under static load,immunohistochemical staining intensity and collagen Type Ⅱ alpha 1 （COL2A 1） gene expression were significantly enhanced （61.54 ± 5.91,P =0.035） and upregulated （1.195 ± 0.040,P =0.000）,respectively,compared with those in the controls （P 〈 0.05）.In contrast,under constant compression,these trends were reversed.Our initial results indicated that short-term static load stimulated the synthesis of collagen Type Ⅱ alpha l;however,sustained constant compression led to progressive degeneration and specifically to a decreased proteoglycan content.Conclusions：A loading and organ culture system for ex vivo rabbit IVD motion segments was developed.Using this system,we were able to study the effects of mechanical stimulation on the biology of IVDs,as well as the pathomechanics of IVD degeneration.

Massive migration promotes the early spread of COVID-19 in China: a study based on a scale-free network

Background The coronavirus disease 2019(COVID-19)epidemic met coincidentally with massive migration before Lunar New Year in China in early 2020.This study is to investigate the relationship between the massive migration and the coronavirus disease 2019(COVID-19)epidemic in China.Methods The epidemic data between January 25th and February 15th and migration data between Jan 1st and Jan 24th were collected from the official websites.Using the R package WGCNA,we established a scale-free network of the selected cities.Correlation analysis was applied to describe the correlation between the Spring Migration and COVID-19 epidemic.Results The epidemic seriousness in Hubei(except the city of Wuhan)was closely correlated with the migration from Wuhan between January 10 and January 24,2020.The epidemic seriousness in the other provinces,municipalities and autonomous regions was largely affected by the immigration from Wuhan.By establishing a scale-free network of the regions,we divided the regions into two modules.The regions in the brown module consisted of three municipalities,nine provincial capitals and other 12 cities.The COVID-19 epidemics in these regions were more likely to be aggravated by migration.Conclusions The migration from Wuhan could partly explain the epidemic seriousness in Hubei Province and other regions.The scale-free network we have established can better evaluate the epidemic.Three municipalities(Beijing,Shanghai and Tianjin),eight provincial capitals(including Nanjing,Changsha et al.)and 12 other cities(including Qingdao,Zhongshan,Shenzhen et al.)were hub cities in the spread of COVID-19 in China.

Ghost spintronic THz-emitter-array microscope

Terahertz(THz)waves show great potential in nondestructive testing,biodetection and cancer imaging.Despite recent progress in THz wave near-field probes/apertures enabling raster scanning of an object’s surface,an efficient,nonscanning,noninvasive,deep subdiffraction imaging technique remains challenging.Here,we demonstrate THz near-field microscopy using a reconfigurable spintronic THz emitter array(STEA)based on the computational ghost imaging principle.By illuminating an object with the reconfigurable STEA followed by computing the correlation,we can reconstruct an image of the object with deep subdiffraction resolution.By applying an external magnetic field,inline polarization rotation of the THz wave is realized,making the fused image contrast polarization-free.Time-of-flight(TOF)measurements of coherent THz pulses further enable objects at different distances or depths to be resolved.The demonstrated ghost spintronic THz-emitter-array microscope(GHOSTEAM)is a radically novel imaging tool for THz near-field imaging,opening paradigm-shifting opportunities for nonintrusive label-free bioimaging in a broadband frequency range from 0.1 to 30 THz(namely,3.3-1000 cm^(−1)).

Terahertz wave avalanche breakdown transistor for high-performance switching

There is still a lack of high-performance terahertz(THz) modulators with wide operation bandwidth and large modulation depth due to the underlying physics limitation behind existing approaches. Meanwhile, for many applications, simple compact THz modulators working straightforward in the transmission mode are also highly desired. Here, we demonstrate a THz modulator with a maximal transmission-amplitude modulation depth of 99.9%(switching ratio of 1000) based on a commonly used silica-on-silicon structure. Different from those reported graphene or metamaterials enhanced proposals, the device we proposed works within a reversible avalanche breakdown region of silicon that has not been studied yet and has the potential to modulate/switch THz waves efficiently. Further, we proved that the modulation depth exceeds 97% in the frequency range from 0.2 to 1 THz in the experiment. The simplicity and generality of this new type of near-perfect THz modulator will undoubtedly attract lots of attention of researchers in the near future due to its potential to be engineered into integrated devices.