Resonant exchange of Chiral Majorana Fermions modulated by two parallel quantum dots

Resonant exchange of the chiral Majorana fermions (MFs) that is coupled to two parallel Majorana zero modes (MZMs) or two parallel quantum dots (QDs) is investigated. We find that, in the two QDs coupling case, the resonant exchange for the chiral MFs is analogous to that in the MZM coupling case. We further propose a circuit based on topological superconductor (TSC), which is formed by the proximity coupling of a quantum anomalous Hall insulator (QAHI) and a s-wave superconductor, to observe the resonant exchange of chiral MFs pairs. The numerical calculations show that the resonant transmission of the chiral MFs can be adjusted by varying the coupling parameters. It is particularly noteworthy that, by only modulating the coupling strength between the two QDs, the resonant exchange may be switched on or off. By adding another MZM, the non-Abelian braidinglike operation can be realized. Therefore, our design scheme may provide another way for non-Abelian braiding operation of MFs and the findings may have potential application value in the realization of topological quantum computers.

Experimental Limits on Solar Reflected Dark Matter with a New Approach on Accelerated-Dark-Matter-Electron Analysis in Semiconductors

Recently a dark matter-electron (DM-electron) paradigm has drawn much attention. Models beyond the standard halo model describing DM accelerated by high energy celestial bodies are under intense examination as well. In this Letter, a velocity components analysis (VCA) method dedicated to swift analysis of accelerated DM-electron interactions via semiconductor detectors is proposed and the first HPGe detector-based accelerated DM-electron analysis is realized. Utilizing the method, the first germanium based constraint on sub-GeV solar reflected DM-electron interaction is presented with the 205.4  kg·day dataset from the CDEX-10 experiment. In the heavy mediator scenario, our result excels in the mass range of 5-15  keV/c^{2}, achieving a 3 orders of magnitude improvement comparing with previous semiconductor experiments. In the light mediator scenario, the strongest laboratory constraint for DM lighter than 0.1  MeV/c^{2} is presented. The result proves the feasibility and demonstrates the vast potential of the VCA technique in future accelerated DM-electron analyses with semiconductor detectors.

[Analysis of contents of different kinds of fatty acids in carotid atherosclerotic plaques]

Objective: To analyze the contents of different kinds of fatty acids in carotid atherosclerotic plaques. Methods: A total of 24 patients who underwent carotid endarterectomy at the Second Affiliated Hospital of Naval Medical University from October 2021 to September 2022 due to moderate and severe carotid artery stenosis were retrospectively enrolled, including 20 males and 4 females, with a median age[M(Q1, Q3)] of 68.5 (63.5, 72.3) years. According to the symptoms of cerebral ischemia, the patients were divided into a symptomatic group (12 cases) and an asymptomatic group (12 cases). Regarding the pathological characteristics, the patients were divided into a stable group (14 cases) and a vulnerable group (10 cases) according to carotid plaque pathology scores. The expression differences of different types of fatty acids in carotid plaques were analyzed by targeted fatty acid metabolomics technology based on ultra-performance liquid chromatography-mass spectrometry (UPLC-ESI-MS/MS) analysis. Results: In the 24 samples, the median amount of fatty acids [M (Q1, Q3)] was 1 113 (330, 5 897) ng/g. A total of 13 medium and long-chain fatty acids were detected, including saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids. The content of saturated fatty acids was 584 (290, 9 888) ng/g, accounting for the highest proportion of 51.8%. The content of polyunsaturated fatty acids was 1 444 (393, 4 264) ng/g, accounting for 44.4%. The content of monounsaturated fatty acids was 2 793 (1 558, 3 247) ng/g, accounting for 3.8%. The contents of linoleic acid, α-linolenic acid and oleic acid in carotid plaques in the symptomatic group were 1 760 (581, 3 006), 682 (527, 886) and 2 081 (1 358, 2 907) ng/g, respectively, which were lower than those in the asymptomatic group 3 149 (2 226, 4 683), 1 423 (964, 2 270) and 3 178 (2 352, 3 993) ng/g (all P<0.05). The contents of linoleic acid, α-linolenic acid and oleic acid in carotid plaques in the vulnerable group were 1 537 (588, 2 921), 649 (477, 850) and 2 081 (1 129, 2 831) ng/g, respectively, which were lower than those in the stable group 3 149 (2 047, 4 416), 1 423 (940, 2 184) and 3 091 (2 201, 3 973) ng/g (all P<0.05). There were no significant differences in the contents of 11, 14-eicosadienoic acid, γ-linolenic acid, eicosapentaenoic acid, arachidonic acid, erucic acid, margaric acid, pentadecanoic acid, stearic acid, dodecanoic acid and palmitic acid (all P>0.05). Conclusions: Saturated fatty acids are the main type in carotid plaques. The contents of oleic acid, α-linolenic acid and linoleic acid decrease in vulnerable plaques.

[Clinical and genetic characteristics of 9 rare cases with coexistence of dual genetic diagnoses]

Objective: To analyze the clinical and genetic characteristics of pediatric patients with dual genetic diagnoses (DGD). Methods: Clinical and genetic data of pediatric patients with DGD from January 2021 to February 2022 in Peking University First Hospital were collected and analyzed retrospectively. Results: Among the 9 children, 6 were boys and 3 were girls. The age of last visit or follow-up was 5.0 (2.7,6.8) years. The main clinical manifestations included motor retardation, mental retardation, multiple malformations, and skeletal deformity. Cases 1-4 were all all boys, showed myopathic gait, poor running and jumping, and significantly increased level of serum creatine kinase. Disease-causing variations in Duchenne muscular dystrophy (DMD) gene were confirmed by genetic testing. The 4 children were diagnosed with DMD or Becker muscular dystrophy combined with a second genetic disease, including hypertrophic osteoarthropathy, spinal muscular atrophy, fragile X syndrome, and cerebral cavernous malformations type 3, respectively. Cases 5-9 were clinically and genetically diagnosed as COL9A1 gene-related multiple epiphyseal dysplasia type 6 combined with NF1 gene-related neurofibromatosis type 1, COL6A3 gene-related Bethlem myopathy with WNT1 gene-related osteogenesis imperfecta type XV, Turner syndrome (45, X0/46, XX chimera) with TH gene-related Segawa syndrome, Chromosome 22q11.2 microduplication syndrome with DYNC1H1 gene-related autosomal dominant lower extremity-predominant spinal muscular atrophy-1, and ANKRD11 gene-related KBG syndrome combined with IRF2BPL gene-related neurodevelopmental disorder with regression, abnormal movement, language loss and epilepsy. DMD was the most common, and there were 6 autosomal dominant diseases caused by de novo heterozygous pathogenic variations. Conclusions: Pediatric patients with coexistence of double genetic diagnoses show complex phenotypes. When the clinical manifestations and progression are not fully consistent with the diagnosed rare genetic disease, a second rare genetic disease should be considered, and autosomal dominant diseases caused by de novo heterozygous pathogenic variation should be paid attention to. Trio-based whole-exome sequencing combining a variety of molecular genetic tests would be helpful for precise diagnosis.

[Prevalence and related factors of visual disability, hearing disability and comorbidity of visual and hearing disability among the elderly in China]

Objective: To estimate the prevalence of visual disability, hearing disability and comorbidity of visual and hearing disability among the elderly in China, and explore the related factors of comorbidity of visual and hearing disability in the elderly. Methods: This was a cross-sectional study. Based on the Second China National Sample Survey on Disability in 2006, the data of the elderly with visual and hearing disability were extracted and combined for descriptive analysis. Meanwhile, multivariate logistic regression model was used to analyze the related factors of comorbidity of visual and hearing disability among the elderly. Results: A total of 250 752 cases were in the final analysis (119 120 males and 131 632 females), and there were 164 003, 74 156 and 12 593 cases with the age of 65-<75, 75-<85 and ≥ 85 years, respectively. The prevalence of visual disability and hearing disability of the elderly in China was 8.10% (95%CI: 8.00%-8.21%), 13.41% (95%CI: 13.29%-13.54%), respectively, while the prevalence of comorbidity of visual and hearing disability was 1.97% (95%CI: 1.92%-2.02%). The severity of disability of the elderly with comorbidity of visual and hearing disability was higher, and the percentage of mild disabilities (18.31%, 966/5 277) was lower than those with visual (53.06%, 11 208/21 123) or hearing disabilities (32.96%, 11 536/34 995). Moreover, 19.40% (1 024/5 277) of visual or hearing disability occurred in the same year. Multivariate logistic regression analysis showed that education level below primary school (OR=0.65, 95%CI: 0.61-0.70, P<0.001), having a spouse (OR=0.68, 95%CI: 0.64-0.72, P<0.001), living in an urban area (OR=0.77, 95%CI: 0.71-0.82, P<0.001) and having a per capita household income higher than the national average (OR=0.73, 95%CI: 0.68-0.78, P<0.001) were protective factors for comorbidity of visual and hearing disability among the elderly. Conclusions: Visual disability is correlated with hearing disability in the elderly. Attention should be paid to the prevention and control of associated disabilities such as visual and hearing co-disabilities in the elderly population, with emphasis on strengthening publicity and education on prevention and control of visual and hearing disabilities for the elderly who are economically disadvantaged, have no spouse and live in remote areas.

Endoscopic submucosal dissection for early cancers or precancerous lesions of the upper gastrointestinal tract in cirrhotic patients with esophagogastric varices: Ten-year experience from a large tertiary center in China

BACKGROUND AND AIMS

Treatment strategies for early cancers or precancerous lesions of the upper gastrointestinal tract in cirrhotic patients with esophagogastric varices (EGV) are complicated and risky. We aimed to assess the efficacy and safety of endoscopic submucosal dissection (ESD) in the treatment of such patients and explore optimal treatment strategies.

METHODS

We retrospectively enrolled 15 cirrhotic patients with EGV who underwent ESD for early cancers or precancerous lesions of the upper gastrointestinal tract from January 2012 to December 2021 at our center. Clinical features, endoscopic findings, treatment methods, adverse events and follow-up data were analyzed.

RESULTS

Of the 15 patients, 1 had a platelet count <30×1000/mm³. Five were untreated for EGV, 1 was treated after ESD, 6 were treated before ESD, 1 was treated before and during ESD, and 2 were treated during ESD. The R0 resection rate was 100%. Of the 16 mucosal lesions, 15 were ERB-0 or ERB-c1, and 1 was ERB-c2. No patient experienced deterioration in liver function. The only adverse events were fever in 2 patients and postoperative bleeding (PB) in 2 patients. During a median follow-up of 27 months, 1 patient's esophageal HGD recurred at 19 months. No death resulted from the ESD procedure, liver function injury or gastrointestinal tumor itself.

CONCLUSION

ESD is an effective and safe treatment for early cancers or precancerous lesions of the upper gastrointestinal tract in cirrhotic patients with EGV. The incidence of severe adverse events is very low due to the development of individualized clinical treatment strategies.

Constraints on Sub-GeV Dark Matter-Electron Scattering from the CDEX-10 Experiment

We present improved germanium-based constraints on sub-GeV dark matter via dark matter-electron (χ-e) scattering using the 205.4  kg·day dataset from the CDEX-10 experiment. Using a novel calculation technique, we attain predicted χ-e scattering spectra observable in high-purity germanium detectors. In the heavy mediator scenario, our results achieve 3 orders of magnitude of improvement for m_{χ} larger than 80  MeV/c^{2} compared to previous germanium-based χ-e results. We also present the most stringent χ-e cross-section limit to date among experiments using solid-state detectors for m_{χ} larger than 90  MeV/c^{2} with heavy mediators and m_{χ} larger than 100  MeV/c^{2} with electric dipole coupling. The result proves the feasibility and demonstrates the vast potential of a new χ-e detection method with high-purity germanium detectors in ultralow radioactive background.

Exotic Dark Matter Search with the CDEX-10 Experiment at China's Jinping Underground Laboratory

A search for exotic dark matter (DM) in the sub-GeV mass range has been conducted using 205 kg day data taken from a p-type point contact germanium detector of the CDEX-10 experiment at China's Jinping underground laboratory. New low-mass dark matter searching channels, neutral current fermionic DM absorption (χ+A→ν+A) and DM-nucleus 3→2 scattering (χ+χ+A→ϕ+A), have been analyzed with an energy threshold of 160 eVee. No significant signal was found; thus new limits on the DM-nucleon interaction cross section are set for both models at the sub-GeV DM mass region. A cross section limit for the fermionic DM absorption is set to be 2.5×10^{-46}  cm^{2} (90% C.L.) at DM mass of 10  MeV/c^{2}. For the DM-nucleus 3→2 scattering scenario, limits are extended to DM mass of 5 and 14  MeV/c^{2} for the massless dark photon and bound DM final state, respectively.

Observations of the Outer Heliosphere, Heliosheath, and Interstellar Medium

The Voyager spacecraft have left the heliosphere and entered the interstellar medium, making the first observations of the termination shock, heliosheath, and heliopause. New Horizons is observing the solar wind in the outer heliosphere and making the first direct observations of solar wind pickup ions. This paper reviews the observations of the solar wind plasma and magnetic fields throughout the heliosphere and in the interstellar medium.

Observations of the Outer Heliosphere, Heliosheath, and Interstellar Medium

The Voyager spacecraft have left the heliosphere and entered the interstellar medium, making the first observations of the termination shock, heliosheath, and heliopause. New Horizons is observing the solar wind in the outer heliosphere and making the first direct observations of solar wind pickup ions. This paper reviews the observations of the solar wind plasma and magnetic fields throughout the heliosphere and in the interstellar medium.

[Comparative study of three scores in predicting the death risk of severe burn patients]

Objective: To explore the predictive values of the modified Baux score, Belgian Outcome in Burn Injury score, and Ryan score on the death risk of severe burn patients. Methods: A retrospective case series study was conducted. From February 2018 to November 2019, 260 severe burn patients who met the inclusion criteria were admitted to the Department of Burns of the First Affiliated Hospital of Nanchang University, including 158 males and 102 females, aged 36 (3, 53) years. According to the final outcome, the patients were divided into survival group (n=229) and death group (n=31). Data of patients were compared and statistically analyzed with chi-square test or Mann-Whitney U test between the two groups, including the gender, age, cause of burn, site of burn, total burn area, depth of burn, combined inhalation injury, and combined underlying diseases on admission, and the modified Baux score, Belgian Outcome in Burn Injury score, and Ryan score calculated based on part of the aforementioned data. The Kendall tau-b coefficient method was used to analyze the consistency of the above-mentioned three scores in 260 severe burn patients. The receiver operating characteristic (ROC) curves of the above-mentioned three scores predicting the death risk of 260 severe burn patients were drawn, and the area under the curve (AUC), the optimal threshold, and the sensitivity and specificity under the optimal threshold were calculated. The quality of AUC of the above-mentioned three scores was compared by Delong test. Results: The gender, site of burn, and depth of burn of patients between the two groups were all similar (P>0.05). The age, total burn area, proportion of flame burn, proportion of combined inhalation injury, and proportion of combined underlying diseases of patients in death group were significantly higher than those in survival group (with Z values of 5.53 and 17.78, respectively, χ2 values of 16.23, 15.89, and 17.78, respectively, P<0.01); the modified Baux score, Belgian Outcome in Burn Injury score, and Ryan score of patients in death group were 142 (115, 155), 7 (5, 7), 2 (2, 3), all significantly higher than 64 (27, 87), 1 (0, 3), 0 (0, 1) in survival group (with Z values of 7.91, 7.64, and 7.61, respectively, P<0.01). In 260 severe burn patients, the results between the modified Baux score and Ryan score, modified Baux score and Belgian Outcome in Burn Injury score, Ryan score and Belgian Outcome in Burn Injury score were significantly consistent (with Kendall tau-b coefficients of 0.75, 0.71, and 0.86, respectively, P<0.01). The AUCs of ROC curves of the modified Baux score, Belgian Outcome in Burn Injury score, and Ryan score for predicting the death risk of 260 severe burn patients were 0.92, 0.89, and 0.85, respectively (with 95% confidence intervals of 0.86-0.98, 0.83-0.95, and 0.78-0.93, respectively, P<0.01); the optimal thresholds were 106.5, 4.5, and 1.5 points, respectively; the sensitivity under the optimal threshold were 88.5%, 76.9%, and 73.1%, respectively, and the specificity under the optimal threshold were 88.5%, 87.2%, and 86.3%, respectively. The modified Baux score was similar to Belgian Outcome in Burn Injury score in the AUC quality (z=1.25, P>0.05), which were both significantly better than the AUC quality of Ryan score (with z values of 2.35 and 2.11, respectively, P<0.05). Conclusions: The modified Baux score, Belgian Outcome in Burn Injury score, and Ryan score have good ability in predicting the death risk of severe burn patients. From the perspective of clinical practice, the modified Baux score is more suitable as a predictive tool for the prognosis of severe burn patients.

[Serum exosomal miRNAs profiling and functional study in patients with non-alcoholic fatty liver disease]

Objective: Differential expression of serum exosomal miRNAs were detected for NAFLD patients and healthy controls, thereby determining the role of serum exosomal miRNAs in the pathogenesis, diagnosis, and treatment of NAFLD. Methods: Four patients with S2-3 NAFLD who shared similar demographic features and personal histories, and matched healthy controls were recruited for high-throughput sequencing of serum exosomal miRNAs. Four miRNAs with the most significant differential expression were verified by qRT-PCR in three groups (S1, S2-3, and control groups) with 20 cases in each group. Target gene prediction was performed for these differentially-expressed miRNAs, along with GO and KEGG enrichment analyses for the target genes. T-test or ANOVA were used for normally distributed data. Wilcoxon rank sum test was used for ranked data and non-normally distributed data. The count data used Pearson chi-square test or Fisher's exact test. Results: There were 19 serum exosomal miRNAs with significantly different levels of expression (P < 0.05) and a fold-change > 2. The expression of hsa-miR-122-5p, hsa-miR-146b-5p, and hsa-miR-197-3P was highest in the S2-3 group, followed by the S1 and control groups (in order); hsa-miR-483-3p expression was higher in the NAFLD group (S1 or S2-3) than the control group. There were 84 pathways significantly enriched in target genes. From 20 pathways closely related to NAFLD, at least 5 target genes which were simultaneously correlated to all 10 pathways were screened (PIK3R2, AKT2, AKT3, MAPK1, and NFKB1). Conclusion: Differential expression of serum exosomal miRNAs was detected in NAFLD patients and healthy controls. Four miRNAs with the greatest fold-changes were assessed to judge the severity of fatty degeneration of the liver. The research findings provide reference for non-invasive identification of new biomarkers and specific targets for NAFLD treatment.

[Study on the feature of cortical auditory evoked potential under different auditory tasks in cochlear implant children]

Objective: To investigate the variation regularity and influencing factors of cortical auditory evoked potential (CAEP) evoked by pure tone, syllable and tone stimuli in cochlear implant (CI) children. Methods: Cortical auditory evoked potential (CAEP) responses were collected from 46 CI children in the sound field. Pure tones with frequencies of 1 kHz and 2 kHz were used as the standard and the deviant respectively in the pure tone stimulation condition. The Chinese Mandarin tokens/ba/-/pa/and/ba1/-/ba4/pairs were used as the stimuli respectively in the syllable and tone stimulation condition. The latency, amplitude and presence rate of P1 and mismatch negative(MMN) were obtained and the correlation between the difficulty of auditory task, the age of hearing month, the duration of severe-profound hearing loss, the wearing history of hearing aid before CI, the hearing threshold of the better ear before CI and the latency and amplitude of P1 and MMN were analyzed. All statistical analyses and figures were conducted using SPSS 25.0. Results: The P1 presence rate of pure tone, syllable and tone group was 100% (17/17), 100% (13/13) and 75.0% (12/16), respectively, with significant difference (χ²=8.214, P=0.016). There was significant difference between pure tone group and tone group (χ²=4.836, P=0.028), but no significant difference between pure tone group and syllable group, syllable group and tone group. The MMN presence rate of pure tone, syllable and tone group was 94.1% (16/17), 84.6% (11/13) and 62.5% (10/16), respectively, but no significant difference among the three groups with different auditory tasks(χ²=0.066, P=0.066). No significant difference was observed among the three groups of different auditory tasks in the latency and amplitude of P1 and MMN. Multiple linear regression analysis showed that the latency of P1 was positively correlated with the difficulty of auditory task and the hearing threshold of the better ear before CI, and negatively correlated with hearing age and the history of hearing aid before CI. The latency of MMN was positively correlated with the difficulty of auditory task, and negatively correlated with hearing age. Conclusions: The P1 presence rate of pure tone auditory task is significantly higher than that of tone auditory task. The difficulty of auditory task, hearing age, the history of hearing aid before CI, and the hearing threshold of the better ear before CI has significant effects on the P1 latency. The difficulty of auditory task and hearing age has significant effects on the MMN latency.

[Application of next-generation sequencing technology in prenatal screening and diagnosis]

Developed rapidly for more than ten years, next-generation sequencing (NGS) has derived a series of new technologies which are widely used clinically, such as noninvasive prenatal testing(NIPT), noninvasive prenatal testing-plus(NIPT Plus), copy number variation sequencing(CNV-seq), and exome sequencing(ES), and plays an important role in birth defects prevention. Moreover, with in-deep development, the superiority of NGS is gradually recognized by clinicians, but there are still many challenges in practical application process. This study specifically elaborates on the development status, technological breakthroughs and future prospects of NGS in the field of prenatal screening and prenatal diagnosis at home and abroad.

[Genetics Analysis of patients with Dravet syndrome due to mosaicism variation of paternal SCN1A gene]

Genetic analysis was performed on a family of fraternal twins affected with Dravet syndrome by genetic tests whose parents were normal. To further analyze the cause of the disease, the fraternal twins were subjected to whole exome sequencing (WES), and the family was verified by Sanger sequencing, with the father semen and peripheral blood DNA were further analysed by target sequencing. The WES test identified a heterozygous c.5348C>T (p.Ala1783Val) variant of the SCN1A gene in the fraternal twins, which was predicted to be pathogenic and was detected in the father peripheral blood and semen, but not in the mother. So the mosaicism mutation of paternal SCN1A gene might be the genetic cause of Dravet syndrome in offspring.

Direct Detection Constraints on Dark Photons with the CDEX-10 Experiment at the China Jinping Underground Laboratory

We report constraints on the dark photon effective kinetic mixing parameter (κ) with data taken from two p-type point-contact germanium detectors of the CDEX-10 experiment at the China Jinping Underground Laboratory. The 90% confidence level upper limits on κ of solar dark photon from 205.4 kg-day exposure are derived, probing new parameter space with masses (m_{V}) from 10 to 300  eV/c^{2} in direct detection experiments. Considering dark photon as the cosmological dark matter, limits at 90% confidence level with m_{V} from 0.1 to 4.0  keV/c^{2} are set from 449.6 kg-day data, with a minimum of κ=1.3×10^{-15} at m_{V}=200  eV/c^{2}.

Search for Light Weakly-Interacting-Massive-Particle Dark Matter by Annual Modulation Analysis with a Point-Contact Germanium Detector at the China Jinping Underground Laboratory

We present results on light weakly interacting massive particle (WIMP) searches with annual modulation (AM) analysis on data from a 1-kg mass p-type point-contact germanium detector of the CDEX-1B experiment at the China Jinping Underground Laboratory. Datasets with a total live time of 3.2 yr within a 4.2-yr span are analyzed with analysis threshold of 250 eVee. Limits on WIMP-nucleus (χ-N) spin-independent cross sections as function of WIMP mass (m_{χ}) at 90% confidence level (C.L.) are derived using the dark matter halo model. Within the context of the standard halo model, the 90% C.L. allowed regions implied by the DAMA/LIBRA and CoGeNT AM-based analysis are excluded at >99.99% and 98% C.L., respectively. These results correspond to the best sensitivity at m_{χ}<6  GeV/c^{2} among WIMP AM measurements to date.

Constraints on Spin-Independent Nucleus Scattering with sub-GeV Weakly Interacting Massive Particle Dark Matter from the CDEX-1B Experiment at the China Jinping Underground Laboratory

We report results on the searches of weakly interacting massive particles (WIMPs) with sub-GeV masses (m_{χ}) via WIMP-nucleus spin-independent scattering with Migdal effect incorporated. Analysis on time-integrated (TI) and annual modulation (AM) effects on CDEX-1B data are performed, with 737.1 kg day exposure and 160 eVee threshold for TI analysis, and 1107.5 kg day exposure and 250 eVee threshold for AM analysis. The sensitive windows in m_{χ} are expanded by an order of magnitude to lower DM masses with Migdal effect incorporated. New limits on σ_{χN}^{SI} at 90% confidence level are derived as 2×10^{-32}∼7×10^{-35}  cm^{2} for TI analysis at m_{χ}∼50-180  MeV/c^{2}, and 3×10^{-32}∼9×10^{-38}  cm^{2} for AM analysis at m_{χ}∼75  MeV/c^{2}-3.0  GeV/c^{2}.

[The timing and surgical choice of surgical treatment for carotid stenosis after radiotherapy]

Objective: To evaluate the safety and efficacy of carotid endarterectomy (CEA) and carotid angioplasty with stenting(CAS) for carotid artery stenosis after radiotherapy. Methods: The clinical data of 73 cases with carotid artery stenosis after radiotherapy from October 2007 to September 2017 were analyzed retrospectively. Among them, 36 cases underwent CEA and 37 cases underwent CAS. Results: No complications occurred during the perioperative period in both groups. During the follow-up period, transient cerebral ischemia occurred in 1 case in the CEA group. There was no in-stent restenosis or adverse events such as stroke or myocardial infarction. In the CAS group, transient cerebral ischemia occurred in 2 cases, postoperative restenosis occurred in 2 cases, and myocardial infarction occurred in 1 case. The restenosis rate and incidence of adverse events were lower in the CEA group. Conclusions: Both surgical methods are safe and effective in the treatment of carotid artery stenosis after radiotherapy. CEA surgery can be more beneficial to long-term outcome, and it is supposed to be the preferred surgical method.

[A modified mouse model of instable carotid atherosclerotic plaque]

Objective: To explore a modified method for constructing a mouse model of instable carotid plaque and provide the mouse model for simulating the development of human instable carotid plaque. Methods: Twenty-four low density lipoprotein receptor deficiency (LDLr-/-), C57BL/6, male mice were randomized into two groups according to computer-generated table, tandem constriction of carotid artery+ high cholesterol diet (tandem surgery group, n=12); sham surgery+ high cholesterol diet(sham surgery group, n=12). After 12 weeks of consecutive feeding, murine carotid artery were collected and analyzed by carotid ultrasound, pathological examination to assess the formation and stability of atherosclerotic plaque. Results: No statistical difference in body weight and blood lipid level between the two groups was observed (all P>0.05). After surgery, through ultrasound biomicroscopy, obvious stenosis at the two sites of tandem constriction and atherosclerotic plaque between the two sites were observed in tandem surgery group. By pathological examination, no plaque was formed in carotid artery in sham surgery group. The lipid area in the stable plaque of innominate artery in sham surgery group and the plaque of carotid artery in tandem surgery group were (4.8±0.6) ×10(4),(10.2±1.1)×10(4) μm(2), respectively. The difference was statistically significant between the two groups (t=12.023,P<0.001). In addition, the thickness of fibrous cap in the above groups were (122.4±17.8), (41.3±20.2) μm, respectively. The difference was statistically significant either (t=9.224, P<0.001). The region of necrotic core were (3.3±0.4)×10(4),(8.1±0.9)×10(4) μm(2).The difference was statistically significant as well (t=13.456, P<0.001). The percentage of macrophages in innominate artery of sham surgery group and in carotid artery of tandem surgery group were (20.8±5.2)%, (38.6±6.4)%, respectively.The percentage of vascular smooth muscle cells were (32.5±7.3)%,(21.2±5.1)%, respectively (t=6.114,3.585, all P<0.05). The results indicated that the plaque in tandem surgery group had severer inflammatory response. Conclusion: Through tandem constriction surgery upon carotid artery in LDL-/-mouse, instable carotid atherosclerotic plaque can be induced, which is less time-consuming, replicable and effective.

[Off-treatment responses and predictors and after long-term anti-HBV therapy with nucleos(t)ide analogues]

Recurrence rate after cessation of nucleos(t)ide analogues remains high in clinical practice. According to current evidences, age, HBsAg level, HB VRNA level, time of consolidation therapy and HBV DNA load were considered to be associated with off-treatment responses after cessation of nucleos(t)ide analogues. Combinative factors of several predictors might perform better in future accompanying with further studies of HBV related markers.

Limits on Light Weakly Interacting Massive Particles from the First 102.8 kg×day Data of the CDEX-10 Experiment

We report the first results of a light weakly interacting massive particles (WIMPs) search from the CDEX-10 experiment with a 10 kg germanium detector array immersed in liquid nitrogen at the China Jinping Underground Laboratory with a physics data size of 102.8 kg day. At an analysis threshold of 160 eVee, improved limits of 8×10^{-42} and 3×10^{-36}  cm^{2} at a 90% confidence level on spin-independent and spin-dependent WIMP-nucleon cross sections, respectively, at a WIMP mass (m_{χ}) of 5  GeV/c^{2} are achieved. The lower reach of m_{χ} is extended to 2  GeV/c^{2}.

[Effectiveness of microsurgical crossover anastomosis in treating complicated obstructive azoospermia]

Objective: To evaluate the efficacy and safety of microsurgical crossover vasovasostomy in treating complicated obstructive azoospermia. Methods: The data of 14 patients with complicated obstructive azoospermia treated with microsurgical crossover vasovasostomy were reviewed from October 2012 to March 2016.Ten of them underwent microsurgical crossover vasovasostomy. Intraoperative exploration revealed that 2 patients had vas deferens injury and contralateral testicular atrophy or epididymal obstruction due to previous hernia repair; 7 patients had obstruction of intracorporeal vas deferens on one side and epididymal obstruction on the other side; the other 1 patient had unilateral vasal obstruction with contralateral epididymal obstruction. Furthermore, 4 patients underwent microsurgical crossover vasoepididymostomy, including 3 patients who had obstruction at caput epididymis on one side, and obstruction at cauda epididymis and distal vas deferens on the other side; the other patient had absence of vas deferens in the scrotum on one side, and testicular atrophy on the other side. Regular follow-up visits were conducted after the surgery. Results: Two patients were lost to follow-up; the other 12 patients were follow-up for an average of 11 (range: 2-23) months. In the 10 cases receiving microsurgical crossover vasovasostomy (including 2 patients lost to follow-up), 1 has not undergone semen re-analysis, 6 were confirmed patent, including 3 reporting spontaneous pregnancy. The patency rate in the 4 patients receiving microsurgical crosseover vasoepididymostomy was 2/4, with 1 patient reporting spontaneous pregnancy. There was no complaint of discomfort or complications following the surgery. Conclusions: Microsurgical crossover anastomosis may be effective and safe for patients with complicated obstructive azoospermia, according to preoperative assessment and intraoperative exploration. It allows natural conception for patients with refractory infertility. The microsurgical crossover anastomosis could be an effective therapy to achieve satisfactory patency of vas deferens.

Study of the association between hemorrhage and the position of hemorrhagic stigmata in patients with esophageal varices

The aim of the present study was to investigate the predilection position of hemorrhagic stigmata (HS) in patients with esophageal variceal hemorrhage and provide guidance on endoscopic therapy for esophageal varices. The clinical characteristics, particularly the endoscopic manifestations of HS, in the patients who presented with gastroesophageal variceal hemorrhage and cirrhosis between January 2003 and December 2013 at our hospital were summarized and patients were grouped according to the distance of the lesion site to incisors at 35-40 and ~30 cm. The association between the location of HS and active hemorrhage was assessed. The location of hemorrhage and HS at 35-40 cm from the incisors was more common in esophageal varices patients, followed by the location at ~30 cm from the incisors (P<0.0001). The incidence of HS in esophageal varices patients in the 35-40 cm group was significantly higher than that in the ~30 cm group except for HS at 9:00 position (P<0.0001). The highest incidence of HS in the ~30 cm group was at the 3:00 position, followed by the 12:00, 6:00 and 9:00 position. Among them, there were significant differences between the 3:00 and 6:00 position, the 3:00 and 9:00 position, and the 9:00 and 12:00 position (P<0.05). The order in the 35-40 cm group was similar to that in the ~30 cm group and the incidence of HS at the 9:00 position was lowest (P<0.05). A certain association between the point of location of HS and hemorrhage was identified. HS located at 35-40 cm from the lesion site to incisors was identified to be most likely to bleed, followed by that located at ~30 cm. In addition, the incidence of HS at 9:00 position was found to be lower than that in the other positions. Therefore, HS located at ~30 cm and 35-40 cm from the lesion site to incisors should be paid attention to and the 3:00, 12:00 and 6:00 rather than the 9:00 position should be prioritized during endoscopic treatment, particularly in emergency situations.

Isolation and characterization of a chalcone isomerase gene promoter from potato cultivars

Chalcone isomerase (CHI) is a key enzyme involved in anthocyanin metabolism. Previous research on CHI has mainly focused on cDNA cloning and gene expression. In the current study, the 1425-bp potato CHI promoter (PCP) was isolated from four potato cultivars (Heijingang, Zhongshu 7, Désirée, and Favorita) using PCR and DNA sequencing. The PCP contained many cis-regulatory elements (CREs) related to anthocyanin metabolism, tissue specificity, light response, stress, and hormone induction. Of the PCP CREs identified, 19 were common to those found in the higher plants examined, based on plant CRE databases. Multiple sequence alignment showed six single nucleotide variation sites in PCP among the potato cultivars examined, resulting in changes in the number of CREs connected with tissue specificity, anthocyanin metabolism, and light response. The 665-bp PCP fragments from Favorita and 1425-bp PCP fragments from Heijingang were used to construct plant expression vectors, which may be a useful tool for biological engineering. A transient expression assay demonstrated that the two PCP fragments from Heijingang could direct the expression of a green fluorescent protein gene in onion epidermis and a β-glucuronidase gene in all potato tuber tissues with different colors, suggesting that the single nucleotide variation in the PCP did not affect its activity, and that silencing of the CHI gene in Favorita may be attributed to other regulatory factors.

Diversity and degradation mechanism of an anaerobic bacterial community treating phenolic wastewater with sulfate as an electron acceptor

Petrochemical wastewater often contains high concentrations of phenol and sulfate that must be properly treated to meet discharge standards. This study acclimated anaerobic-activated sludge to treat saline phenolic wastewater with sulfate reduction and clarified the diversity and degradation mechanism of the microbial community. The active sludge in an upflow anaerobic sludge blanket (UASB) reactor could remove 90 % of phenol and maintain the effluent concentration of SO4 (2-) below 400 mg/L. Cloning and sequencing showed that Clostridium spp. and Desulfotomaculum spp. were major phenol-degrading bacteria. Phenol was probably degraded through the carboxylation pathway and sulfate reduction catalyzed by adenosine-5'-phosphosulfate (APS) reductase and dissimilatory sulfite reductase (DSR). A real-time polymerase chain reaction (RT-PCR) showed that as phenol concentration increased, the quantities of 16S rRNA gene, dsrB, and mcrA in the sludge all decreased. The relative abundance of dsrB dropped to 12.46 %, while that of mcrA increased to 56.18 %. The change in the electron flow ratio suggested that the chemical oxygen demand (COD) was removed mainly by sulfate-reducing bacteria under a phenol concentration of 420 mg/L, whereas it was removed mainly by methanogens above 630 mg/L.

Installing and thereafter removing an aberrant prosthesis elicited opposite remodelling responses in growing mouse temporomandibular joints

Temporomandibular joint (TMJ) displays a high remodelling capability. The current purpose was to investigate the differences between mandibular condylar remodelling responses of growing mice to installation and removal of unilateral anterior crossbite (UAC) prosthesis. Twenty-four mice were divided into one mock control group and two UAC groups. Unilateral anterior crossbite was created by installing a pair of prosthesis to left-side maxillary and mandibular incisors. Unilateral anterior crossbite was removed in removal group at 3 weeks but remained in UAC group. Temporomandibular joints were sampled at 7 weeks. Changes in condylar cartilage and subchondral bone were assessed by histology and in vivo micro-CT. Real-time PCR and immunohistochemistry were performed to evaluate expression changes in ADAMTS-5, MMP-3, MMP-9, MMP-13, IL-1, TNF-α, OPG and RANKL. Statistical analysis was performed at α = 0.05. Temporomandibular joint cartilage degradation was induced by UAC as previously reported but was reversed by removal of UAC. The dropped cartilage thickness, chondrocyte number and collagen II-positive area, the increased expression levels of Adamts-5, Mmp3, 9, 13, Tnf-α and Il-1β in cartilage, the decreased ratio of OPG/RANKL in both condylar cartilage and subchondral bone, the loss of TMJ subchondral bone and the increase in the TRAP-positive cells in subchondral bone were all reversed in the removal group (P < 0.05). The growing mouse TMJ condyle displays a high remodelling capability which can be degenerative and rehabilitative, respectively, in response to placement and thereafter removal of the aberrant prosthesis. Eliminating aberrant prosthesis is helpful to promote the degraded condyle to recover.

HIF-1α -1790G>A polymorphism significantly increases the risk of digestive tract cancer: A meta-analysis

AIM: To investigate the association between hypoxia-inducible factor-1α (HIF-1α) polymorphisms (-1772C>T and -1790G>A) and the risk of digestive tract cancer.

METHODS: A total of 13 eligible studies were retrieved from PubMed, EMBASE, and the China National Knowledge Infrastructure database. The odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to estimate the strength of the associations.

RESULTS: By pooling the eligible studies, we found that the HIF-1α -1772C>T polymorphism was not associated with the risk of developing digestive tract cancer (dominant comparison, OR: 1.156; 95%CI: 0.839-1.593; P_{heterogeneity} = 0.007), and no significant association was found in the Asian population or the Caucasian population. However, for the -1790G>A polymorphism, carriers of the variant -1790A allele had a significantly increased risk of digestive tract cancer compared with those with the wildtype -1790G allele (dominant comparison, OR: 3.252; 95%CI: 1.661-6.368; P_{heterogeneity} < 0.001). Additionally, this increased risk of digestive cancer was only detected in Asians; there was no significant association in Caucasians.

CONCLUSION: This meta-analysis demonstrates that the HIF-1α -1790G>A polymorphism is associated with a significantly increased risk of digestive tract cancer, while the -1772C>T polymorphism is not.

The influence of microgravity on Euglena gracilis as studied on Shenzhou 8

The German Aerospace Center (DLR) enabled German participation in the joint space campaign on the unmanned Shenzhou 8 spacecraft in November 2011. In this report, the effect of microgravity on Euglena gracilis cells is described. Custom-made dual compartment cell fixation units (containing cells in one chamber and fixative - RNA lysis buffer - in another one) were enclosed in a small container and placed in the Simbox incubator, which is an experiment support system. Cells were fixed by injecting them with fixative at different time intervals. In addition to stationary experiment slots, Simbox provides a 1 g reference centrifuge. Cell fixation units were mounted in microgravity and 1 g reference positions of Simbox. Two Simbox incubators were used, one for space flight and the other as ground reference. Cells were fixed soon after launch and shortly before return of the spaceship. Due to technical problems, only early in-flight samples (about 40 min after launch microgravity and corresponding 1 g reference) were fully mixed with fixative, therefore only data from those samples are presented. Transcription of several genes involved in signal transduction, oxidative stress defence, cell cycle regulation and heat shock responses was investigated with quantitative PCR. The data indicate that Euglena cells suffer stress upon short-term exposure to microgravity; various stress-induced genes were up-regulated. Of 32 tested genes, 18 were up-regulated, one down-regulated and the rest remained unaltered. These findings are in a good agreement with results from other research groups using other organisms.

Prevalence of minimal hepatic encephalopathy and quality of life evaluations in hospitalized cirrhotic patients in China

AIM: To investigate the prevalence of minimal hepatic encephalopathy (MHE) and to assess corresponding health-related quality of life (HRQoL) in hospitalized cirrhotic patients in China.

METHODS: This multi-center cross-sectional study included 16 teaching hospitals, which were members of “Hepatobiliary Cooperation Group, Society of Gastroenterology, Chinese Medical Association”, from different areas of China carried out between June and October in 2011. All the eligible hospitalized cirrhotic patients (n = 538) were required to complete triplicate number connection tests combined with one digit symbol test for diagnosing MHE. Patients’ clinical examination data were complemented by a modified questionnaire assessing HRQoL. Written informed consent was obtained from each patient.

RESULTS: Male was predominant (68.6%) in 519 patients who met the criteria of the study, with a mean age of 49.17 ± 11.02 years. The most common cause of liver cirrhosis was chronic hepatitis B (55.9%). The prevalence of MHE was 39.9% and varied by Child-Pugh-Classification score (CPC-A: 24.8%, CPC-B: 39.4% and CPC-C: 56.1%, P < 0.01). MHE (P < 0.01) and higher CPC scores (P < 0.01) were associated with a high HRQoL scores (reflecting poorer quality of life). The prevalence of MHE was proportionate to CPC (P = 0.01) and high quality of life scores (P = 0.01).

CONCLUSION: Hospitalized cirrhotic patients have a high prevalence of MHE that is proportionate to the degree of liver function and HRQoL impairment.

Influence of long-term drinking alcohol on the cytokines in the rats with endogenous and exogenous lung injury

BACKGROUND

Acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) are syndromes of acute respiratory failure.

PURPOSE

Exploration of the impacts of long-term drinking alcohol on the cytokines of rats with endogenous and exogenous lung injuries.

MATERIALS AND METHODS

Through giving the model rats long-term drinking alcohol or water, we acquired the changes of the cytokines in the serum and bronchoalveolar lavage fluid (BALF) of these rats with lung injuries due to different incentives.

RESULTS

The partial pressure of oxygen in rats with lung damage after long-term drinking alcohol were significantly lower than those drinking water group (p < 0.05); W/D values of groups drinking alcohol were significantly higher than those drinking water (p < 0.05); The levels of TNF-alpha, IL-6 and IL-10 in the serum and BALF were significantly higher in the group drinking alcohol (p < 0.01). While the cytokine levels in the serum of the rats with exogenous lung injury were higher than those of rats with endogenous lung injury (p < 0.05), the cytokines in the BALF of the rats with endogenous lung injury were higher than those with exogenous lung injury (p < 0.05).

CONCLUSIONS

Long-term drinking alcohol can aggravate the inflammatory response induced by the exogenous lung injury. The expression of TNF-α, IL-6 and IL-10 are different according to the different ways that lead to the acute lung injury.

Growth and antioxidant system of Escherichia coli in response to microcystin-RR

Microcystins are a kind of cyclic hepatoxins produced by many species of cyanobacteria. The toxic effects of microcystins on animals and plants have been well studied. However, the reports about the effects of microcystins on microbial cells are very limited. In present paper, Escherichia coli was undertaken to determine the effect of microcystin-RR. These results suggested that microcystin-RR could prolong the growth of E. coli when exposed to high concentrations of microcystin-RR and cause the accumulation of ROS and induce the oxidant stress for a short time. The antioxidant system protects E. coli from oxidative damage.

Curative effect of transsplenic human mesochymal stem cells transplantation on acetaminophen-induced acute liver injury in mice

AIM: To assess efficacy of transsplenic human mesochymal stem cells (hMSCs) transplantation on acetaminophen-induced acute liver injury in mice.

METHODS: An animal model of acetaminophen-induced acute liver injury was established. Twenty severe combined immunodeficiency mice (SCID mice) were randomly divided into 2 groups: transsplenic hMSCs transplantation group (n = 10) and control group (n = 10). After transsplenic hMSCs transplantation, liver function test, immunofluorescence method, fluorescence microscopy and reticular fiber staining were performed to observe hepatic acinus and liver function of SCID rats.

RESULTS: Liver function of SCID mice after transsplenic hMSCs transplantation was improved significantly compared with controls (at d 28, ALT: 26.3 U/L vs 50.1 U/L, P < 0.01; AST: 108.0 U/L vs 154.3 U/L, P < 0.05; ALB: 40.0 g/L vs 31.9 g/L, P < 0.05). Fluorescence microscopy indicated hMSCs through transsplenic transplantation began to reside, differentiate and proliferate in spleen and liver in large number. Immunofluorescence method showed remarkable improvement of hepatic acinus following transsplenic hMSCs transplantation.

CONCLUSION: Transsplenic hMSCs transplantation improves acute liver injury induced by acetaminophen in SCID mice and human mesochymal stem cells are able to proliferate in liver. Transsplenic transplantation is effective for hMSCs transplantation.

Real-time studies on microalgae under microgravity

Using remote sensing technique, we investigated real-time Nostoc sphaeroides Kütz (Cyanobacterium) in Closed System under microgravity by SHENZHOU-2 spacecraft in January 2001. The experiments had 1 g centrifuges in space for control and ground control group experiments were also carried out in the same equipments and under the same controlled condition. The data about the population growth of Nostoc sp. of experiments and temperature changes of system were got from spacecraft every minute. From the data, we can find that population growth of Nostoc sp. in microgravity group was higher than that of other groups in space or on ground, even though both the control 1 g group in space and 1 g group on ground indicated same increasing characteristics in experiments. The growth rate of 1.4 g group (centrifuged group on ground) was also promoted during experiment. The temperature changes of systems are also affected by gravity and light. Some aspects about those differences were discussed. From the discussion of these results during experiment, it can be found that gravity is the major factor to lead to these changes.

Margulis' theory on division of labour in cells revisited

Division of labour is a marked feature of multicellular organisms. Margulis proposed that the ancestors of metazoans had only one microtubule organizing center (MTOC), so they could not move and divide simultaneously. Selection for simultaneous movement and cell division had driven the division of labour between cells. However, no evidence or explanation for this assumption was provided. Why could the unicellular ancestors not have multiple MTOCs? The gain and loss of three possible strategies are discussed. It was found that the advantage of one or two MTOC per cell is environment-dependent. Unicellular organisms with only one MTOC per cell are favored only in resource-limited environments without strong predatory pressure. If division of labour occurring in a bicellular organism just makes simultaneous movement and cell division possible, the possibility of its fixation by natural selection is very low because a somatic cell performing the function of an MTOC is obviously wasting resources. Evolutionary biologists should search for other selective forces for division of labour in cells.

Metabolism and pharmacokinetics, in the rat, of (R)-N-(2-Heptyl)Methyl-propargylamine (R-2HMP), a new potent monoamine oxidase inhibitor and antiapoptotic agent

(R)-N-(2-Heptyl)-N-methylpropargylamine (R-2HMP) is a monoamine oxidase inhibitor and putative antiapoptotic agent analogous to (R)-deprenyl. In the rat, the major amine metabolites of R-2HMP have been identified as (R)-N-2-heptylmethylamine (R-2HMA), (R)-N-2-heptylpropargylamine (R-2HPA), and (R)-2-heptylamine (R-2HA). After R-2HMP was administered s.c. to male Wistar rats, it was observed that the greatest concentration was of the original drug followed in decreasing order by R-2HMA, R-2HPA, and R-2HA in brain, liver, and plasma at all times after administration. The greatest concentrations of the three metabolites were found in brain followed by liver and plasma, and the peak concentrations occurred between 15 and 30 min after administration. After oral administration, the liver contained the greatest concentrations of drug and metabolites, and, again, the peak concentrations occurred at about 15 min. In all cases, depropargylation appears to occur at a faster rate than demethylation. After s.c. administration, R-2HMP and its metabolites exhibited biexponential redistribution and elimination losses. Half-lives of the compounds in brain for the redistribution phase were: R-2HMP, 10 min; R-2HMA, 11 min; R-2HPA, 16 min; and R-2HA, 15 min.

Application of LC-NMR and LC-MS to the identification of degradation products of a protease inhibitor in dosage formulations

LC-NMR and LC-MS were applied to the characterization of six degradation products of a protease inhibitor, N-hydroxy-1,3-di-[4-ethoxybenzenesulphonyl]-5,5-dimethyl-[1,3]c yclohexyldiazine-2-carboxamide, in a dosage formulation. A reversed-phase HPLC method was developed for the separation of the parent compound and its six degradation products. LC-MS was then utilized to obtain the molecular weight and fragmentation information using an electrospray ionization (ESI) interface in the positive ion mode. LC-NMR was employed to acquire detailed structural information using a selective solvent suppression pulse sequence in the stop flow mode. This work demonstrated the usefulness of this integrated approach for the rapid and unambiguous identification of drug compounds and their degradation products in dosage formulations.

Combining direct methods with isomorphous replacement or anomalous scattering data. VIII. Phasing experimental SIR data with the replacing atoms in a centrosymmetric arrangement

A multisolution direct method has been proposed to resolve the phase ambiguity intrinsic in single isomorphous replacement data of proteins with the replacing atoms in a centrosymmetric arrangement. The phase ambiguity of each reflection is in fact a 'sign ambiguity' of the phase difference between the phase of the native protein and that of the replacing atoms, i.e. +/- |Deltatheta| = theta - theta'. The P+ probability formula can be used to derive the signs. The multisolution phasing procedure is initiated using random starting values of P+. A cluster analysis is used instead of figures of merit to find the correct solution. The direct-method phases can be further improved by density-modification techniques. The method was tested with the experimental SIR data at 2 A resolution from a known protein aPP; satisfactory results were obtained.

Transient frequency and intensity sensitivities of central auditory neurons determined with sweep tone

To determine the transient frequency and intensity sensitivities of central auditory neurons, we implemented an exponential sweep tone stimulus (2 sec in period, mean sweep rate 3.3 octave/sec), intensity of which varied systematically across trials. Response of single units to the stimulus was studied at the inferior colliculus (IC) of urethane-anesthetized rats. Most IC units responded to the sweep tone by one or more transient increases in discharge rate. The area of increased discharge, or response area (RA), was delineated on the frequency-intensity plane. The tip of RA gives the best frequency (BF) and minimum threshold (MT) of the cell. We also compared the BF and MT concurrently obtained with another method, viz., the conventional 'audio-visual' method of subjective judgment. Results showed that for the same population of cells (n=130), correlation between the two methods is better for BF (r=0.91) than for MT (r=0.78). Such discrepancy was discussed in relation to the response characteristics of these central auditory neurons.