Enhanced Sensing Mechanism Based on Shifting an Exceptional Point.

Non-Hermitian systems associated with exceptional points (EPs) are expected to demonstrate a giant response enhancement for various sensors. The widely investigated enhancement mechanism based on diverging from an EP should destroy the EP and further limits its applications for multiple sensing scenarios in a time sequence. To break the above limit, here, we proposed a new enhanced sensing mechanism based on shifting an EP. Different from the mechanism of diverging from an EP, our scheme is an EP nondemolition and the giant enhancement of response is acquired by a slight shift of the EP along the parameter axis induced by perturbation. The new sensing mechanism can promise the most effective response enhancement for all sensors in the case of multiple sensing in a time sequence. To verify our sensing mechanism, we construct a mass sensor and a gyroscope with concrete physical implementations. Our work will deepen the understanding of EP-based sensing and inspire designing various high-sensitivity sensors in different physical systems.

Tuning the Quantum Properties of ZnO Devices by Modulating Bulk Length and Doping.

The quantum transport properties of ZnO devices with five different bulk configurations are investigated with numerical methods. The calculation results reveal that the transport property at a higher energy range can be tuned by changing the length of central scattering. By substituting some Zn atoms with Cu atoms, it is found that the doped Cu atoms have an obvious effect on the quantum properties at the entire energy range investigated, and could result in different transmission. The properties of ZnO devices are also influenced by the doping positions of Cu atoms. The tuning mechanism relies on the shifting of carrier distributions in the scattering center of the device.

Heterodyne detection of backscattering for whispering-gallery-mode sensors.

Whispering-gallery-mode (WGM) microcavities have shown significant applications in nanoparticle sensing for environmental monitoring and biological analysis. However, the enhancement of detection resolution often calls for active cavities or elaborate structural designs, leading to an increase of fabrication complexity and cost. Herein, heterodyne amplification is implemented in WGM microsensors based on backscattering detection mechanism. By interfering with an exotic reference laser, the reflecting light backscattered by perturbation targets can be strongly enlarged, yielding an easy-to-resolve and consequently sensitive microsensor. The dependence of detection laser frequency has also been characterized with the assistance of optothermal dynamics. We show that exploiting heterodyne interferometry boosts the detection of weak signals in microresonator systems and provides a fertile ground for optical microsensor development.

Simultaneous ground-state cooling of multiple degenerate mechanical modes through the cross-Kerr effect.

Simultaneous ground-state cooling of multiple degenerate mechanical modes is a difficult issue in optomechanical systems, owing to the existence of the dark mode effect. Here we propose a universal and scalable method to break the dark mode effect of two degenerate mechanical modes by introducing cross-Kerr (CK) nonlinearity. At most, four stable steady states can be achieved in our scheme in the presence of the CK effect, unlike the bistable behavior of the standard optomechanical system. Under a constant input laser power, the effective detuning and mechanical resonant frequency can be modulated by the CK nonlinearity, resulting in an optimal CK coupling strength for cooling. Similarly, there will be an optimal input laser power for cooling when the CK coupling strength stays fixed. Our scheme can be extended to break the dark mode effect of multiple degenerate mechanical modes by introducing more than one CK effect. To fulfill the requirement of the simultaneous ground-state cooling of N multiple degenerate mechanical modes, N - 1 CK effects with different strengths are needed. Our proposal provides new, to the best of our knowledge. insights into dark mode control and might pave the way to manipulating multiple quantum states in a macroscopic system.

Phase-controlled dual-wavelength resonance in a self-coupling whispering-gallery-mode microcavity.

We report a novel, to the best of our knowledge, way to achieve phase-controlled dual-wavelength resonance based on whispering-gallery-mode (WGM) microcavities experimentally. With the help of a feedback waveguide, not only two optical pathways but also a unidirectional coupling between counter-propagating waves are formed, which is the requirement of all-optical analogues of electromagnetically induced transparency and Autler-Townes splitting. By adjusting the accumulating phase introduced from the fiber waveguide, we observe the signal lineshape changes from symmetric to asymmetric, i.e., the resonant transmission and extinction ratio of two splitting modes can be controlled, which brings a new degree of freedom to the WGM resonator system. These results may boost the development of quantum state control and pave the way for reconfiguring devices such as narrow-band filters.

The Involvement of the RhoA/ROCK Signaling Pathway in Hypersensitivity Reactions Induced by Paclitaxel Injection.

A high incidence of hypersensitivity reactions (HSRs) largely limits the use of paclitaxel injection. Currently, these reactions are considered to be mediated by histamine release and complement activation. However, the evidence is insufficient and the molecular mechanism involved in paclitaxel injection-induced HSRs is still incompletely understood. In this study, a mice model mimicking vascular hyperpermeability was applied. The vascular leakage induced merely by excipients (polyoxyl 35 castor oil) was equivalent to the reactions evoked by paclitaxel injection under the same conditions. Treatment with paclitaxel injection could cause rapid histamine release. The vascular exudation was dramatically inhibited by pretreatment with a histamine antagonist. No significant change in paclitaxel injection-induced HSRs was observed in complement-deficient and complement-depleted mice. The RhoA/ROCK signaling pathway was activated by paclitaxel injection. Moreover, the ROCK inhibitor showed a protective effect on vascular leakage in the ears and on inflammation in the lungs. In conclusion, this study provided a suitable mice model for investigating the HSRs characterized by vascular hyperpermeability and confirmed the main sensitization of excipients in paclitaxel injection. Histamine release and RhoA/ROCK pathway activation, rather than complement activation, played an important role in paclitaxel injection-induced HSRs. Furthermore, the ROCK inhibitor may provide a potential preventive approach for paclitaxel injection side effects.

[Mechanism of nephrotoxicity of rhubarb in rats].

The aim of this study was to investigate the renal toxicity of rhubarb and its mechanism. The SD rats were randomly divided into three groups: normal group and two rhubarb extract groups (16, 2 g·kg⁻¹). According to the dose conversion method between human and animal, rhubarb 16 g·kg⁻¹ and 2 g·kg⁻¹ were equivalent to 10 times and 1.25 times of human clinical dose respectively. Rhubarb extract was administered by a gastric gavage to rats once daily for 30 days. Serum urea nitrogen （BUN）, creatinine （CRE） and urine KIM-1, NGAL and renal morphology were analyzed. The expressions of OAT1, OAT3 and clusterin mRNA in kidney were measured. The results showed that the low dose of rhubarb had no obvious renal toxicity. The high dose group showed mild and moderate renal injury and a down-regulation of clusterin mRNA expression in the kidney tissue. The renal toxicity in male animals was heavier than that in female animals. There was no significant change in blood BUN and CRE in the high dose group. But urine NGAL level of the high dose group increased by 51.53% compared with normal group, of which male animals increased more significantly (P<0.05, compared with the normal group). The expressions of renal OAT1 and OAT3 mRNA in the low dose group were obviously higher than that in the normal group. The results indicated that the high dose of rhubarb could cause the renal toxicity. The dosage should be controlled reasonably in the clinical use. OAT1 and OAT3 mRNA related to anionic transport in kidney tissue played a compensatory protective role in rhubarb-induced renal injury. But the compensatory effect is relatively weak at the high dose level. In addition, routine renal function indicators BUN and CRE had limitation for monitoring the kidney toxicity of rhubarb. It is suggested that urine NGAL detection might be helpful for monitoring the renal toxicity of rhubarb.

Transformation of tobacco plants by Yali PPO-GFP fusion gene and observation of subcellular localization.

To explore the subcellular localization of Polyphenol oxidase (PPO) from Pyrus bretschneideri, the 1779 bp cDNA of PPO gene excluding the termination codon TAA was cloned and fused with GFP to construct a binary vector pBI121-PPO-GFP. Then, the binary vector was transformed into Nicotiana tabacum by the tumefanciens-mediated method. Using confocal laser scanning microscopy, green fluorescent signals were localized in chloroplasts of the transformed Nicotiana tabacum cell, suggesting that the Polyphenol oxidase from Pyrus bretschneideri was a chloroplast protein.

[Review on requirements of drug allergy or pseudoallergic reactions in pre-clinical evaluation].

Drug allergy and pseudoallergic reactions are main adverse drug reactions. Allergy is mainly induced by the immunogenicity of drug, drug metabolic products or drug additive. Pseudoallergic reactions may result from the irritation or activation of inflammatory material release. Pre-clinical evaluation of drug allergy and pseudoallergic reactions is included in immunotoxicity evaluation. Now there is no in vivo or in vitro method that could predict all kinds of allergy or pseudoallergic reactions due to the different mechanisms. In the past few years, FDA, SFDA OECD, ICH and WHO have published several guidelines on per-clinical immunotoxicity evaluation, however, no agreement has been reached on allergy and pseudoallergic reactions evaluation. This article reviews the requirements of allergy and pseudoallergic reactions in pre-clinical evaluation.

[Genotoxicity research thought and method on traditional Chinese medicine].

Genotoxicity research takes an important place in traditional Chinese medicine safety evaluation. Genotoxicity test on traditional Chinese medicine has been paid great attention since 1970s. Currently, the most developed genotoxicity test methods included: bacterial reverse mutation test and mouse lymphoma assay which are used to detect relevant genetic changes, micronucleus test and chromosomal analysis which are used to measure chromosomal aberration, and single cell electrophoresis assay which is used to test DNA damage. This article reviews research progress on genotoxicity of traditional Chinese medicine, evaluation methods of genotoxicity, the problems and solutions on genotoxicity evaluation of traditional Chinese medicine, and new technique used in genotoxicity test.

[Preclinical evaluation of pseudoallergic reactions on Chinese herbal injections: study on animal strain and gender difference].

Pseudoallergic reactions occured after the first administration of patients, and the pathogenic mechanisms of them were different from the allergic reactions which needed excitation after antigen sensitization. To provide a basis for evaluation, clinical use and drug development of pseudoallergic reactions, the models were established by two kinds of Chinese herbal injections (CHI) both on different strain or gender mice. With the use of ICR, Kunming, BALB/C, C57 mice, pseudoallergic tests of two CHI were conducted to compare the sensitivity of four strains mice, and compared the differences in male and female animals. Test substances contain 0.8% Evans blue (EB) were intravenously injected into different strain and gender mice. Scores of ear blue staining and quantitation of ear EB exudation were the parameters for pseudoallergic reaction. Results of strain difference indicated that both CHI A and B could cause severe pseudoallergic reactions indicated by obvious vascular hyperpermeability on ICR mice. The pseudoallergic reactions in ICR mice are more obvious under the the same dose of injection, which stated the sensibility of ICR mice. And the reactions of KM mice and BALB/C mice were slightly reduced which compared to ICR mice, even alomost nothing on C57 mice. Comparison results of gender difference showed that one CHI was not have significant difference in male and female animals, but male animals were more susceptible than females on another CHI. Therefore, ICR mice were preferable experimental strain on the model of pseudoallergic reactions induced by CHI A and B. Because of female animals were easily influenced by estrous cycle, the pseudoallergic reactions induced by CHI A and B select and use male mice befittingly.

[Study of screening pseudoallergenic substances of Shuanghuanglian injection].

In this study, chemistry, biology and pharmacology were combinated to screen pseudoallergenic substances of Shuang-huanglian injection (SHLI) so that to establish a scientific and systematic approach to screen pseudoallergenic substances of traditional Chinese medicine injections. The mouse pseudoallergic reaction models were used to screen the pseudoallergic reaction of SHLI's intermediate extract and the intermediate extract's component or ingredient. Among the three intermediates of Shuanghuanglian injection (extract of Scutellaria baicalensis, extract of Lonicera japonica, extract of Forsythia suspensa) , pseudoallergic action of Forsythia suspensa was the strongest, Forsythia suspesnsa's pseudoallergic reaction mainly associated with the composition with largerchemical polarity. Further it was found that forsythiaside A and arctiin which existed in the the composition with largerchemical polarity caused obvious pseudoallergic reactions. SHLI with removal forsythoside A with the technology of HPLC-MS displayed reduced pseudoallergic reaction and a significant improved safety. This study provided a scientific basis for SHLI process improvements and also offered idea and research foundation for screening pseudoallergenic substances injections in other TCM injections.

TET1 partially mediates HDAC inhibitor-induced suppression of breast cancer invasion.

Histone deacetylases (HDACs) are important in chromatin remodeling and epigenetic regulation of gene expression. Histone deacetylase inhibitors (HDACi) have highly effective anti-metastatic and anti-angiogenic activity in various types of cancer, while the molecular mechanisms involved in this process are not fully understood. In the present study, trichostatin A (TSA), a HDACi, was found to suppress MCF-7 breast carcinoma cell invasion and upregulate TET1 expression in a dose-dependent manner. TET1, a dioxygenase involved in cytosine demethylation, is downregulated during breast cancer progression. TET1 knockdown in MCF-7 cells facilitates cell invasion, inhibits the expression of tissue inhibitors of metalloproteinase 2/3 (TIMP2/3) and promotes matrix metalloproteinases (MMP) 2/9 transcriptional activity. Importantly, TET1 depletion impaired the inhibitory effect of TSA on breast cancer cell invasion. Together, these results illustrated a mechanism by which TET1 partially mediates HDACi elicited suppression of breast cancer invasion.

[Experimental study on pseudoallergic reaction of Qingkailing injection].

Pseudoallergic reactions of Qingkailing injection (QKLI) was assessed by vascular hyperpermeability which were indicated by ear blue staining in ICR mice after single intravenous injection of QKLI mixed with Evans blue (EB) and skin blue spot formation in SD rats after intradermal injection of QKLI and intravenous injection of EB. In addition, QKLI-induced histamine, VEGF, TNF-alpha release was measured after ICR mice received the single dosing of QKLI iv. The mild vascular hyperpermeability characterized by ear blue staining could be observed in mice after intravenous injection of QKLI and EB. Intracutaneous injection of 50 micro L of test solution containing QKLI (25,50 microL) in rat back skin caused obvious local vascular hyperpermeability at the injection sites so as to result the larger diameters of blue spots than that in negative control group (P <0. 01). QKLI induced a significant increase of VEGF and a slight elevation of histamine in mice after intravenous administration, while TNF-alpha showed no change after QKLI iv. The results in this study indicated that both intravenous injection and intracutanous injection of QKLI could induce vascular hyperpemeability so as to cause pseudoallergic reaction in mice and rats. QKLI-induced pseudoallergic reaction may be associated with the release of histamine and VEGF.

[Thought and method of reproductive toxicity research in traditional Chinese medicine].

Reproductive toxicity research takes an important place in traditional Chinese medicine pre-clinical safety evaluation. Modern reproductive toxicity experiment includes drug-related miscarriage, fetal death, teratism, and adverse effects on fertility, genital system, embryonic development and fetus, which is different from contraindicated in pregnancy in traditional Chinese medicine theory. Now the three-phases reproductive toxicity study is the method mainly applied in traditional Chinese medicine reproductive toxicity evaluation. Besides that, alternative methods of whole embryos culture and embryonic stem cell test are also used in traditional Chinese medicine embryo toxicity evaluation. This article reviews research progress and pre-clinical evaluation on reproductive toxicity of traditional Chinese medicine.

Toluene removal biofilter modeling.

On the basis of the model proposed by De Visscher and Van Cleemput for methane oxidation in landfill cover soils, simulation models for biofiltration of toluene-contaminated air were performed for biofilters with or without substrate inhibition and operated at constant or varying airflow rates. The toluene oxidizing activity (V(max)) expressions of the derived models clearly indicate that V(max) is not a constant along a biofilter height. The equations derived when V(max) is set to zero can be used to predict the minimum concentration requirement for a viable biofiltration process. The simulation results show that the model of De Visscher and Van Cleemput, modified to incorporate Haldane kinetics, provides a good description of the biofiltration performance for toluene removal biofilters. Predictions of the minimum concentration that can be treated indicate that conventional biofilters are not suitable for indoor air pollutant removal.

[Covert infection of severe acute respiratory syndrome in health-care professionals and its relation to the workload and the type of work].

OBJECTIVE: To study severe acute respiratory syndrome (SARS) covert infection in health-care professionals and its relation to work intensity and type of work. METHODS: Specific antibodies to SARS virus in 1 127 serum specimens from health-care professionals who had a close contact history with patients of SARS and 92 healthy persons were assayed with ELISA. RESULTS: The health-care professionals consisted of 287 men and 840 women, aged 21 - 55 years (mean 34 +/- 9 years). The overall positive rate of specific IgG and IgM was 2.57% (29/1 127); the positive rates in nurses, doctors and laboratory workers, and supervisors were 3.46%, 1.41%, 2.86%, respectively. 34.5% of the infected worked in the ICU, and 65.5% in the general wards. None of them presented clinical SARS. Medical examination was also carried out for 313 people who had close contact with the 29 antibody positive health care professionals, but no clinical SARS was found. CONCLUSIONS: Covert infection can be found in the health-care professionals and it showed no contagiousness. The positive rate of specific antibodies was higher in ICU where the work intensity was higher. The positive rate in nurses was higher than in doctors.