A room temperature ferroelectric material with photoluminescence: (1,3-dicyclohexylimidazole)2MnCl4

Molecular ferroelectric materials have been widely used in capacitors and sensors due to their low cost, light weight, flexibility and good biocompatibility. Organic-inorganic hybrid complexes, on the other hand, have received a great deal of attention in the luminescence field due to their low cost and simple preparation. The combination of ferroelectricity and photoluminescence in organic-inorganic hybrid materials not only leads to tunable optical properties, but also enriches potential applications of multifunctional ferroelectrics in optoelectronic devices. Here, we report a new luminescent ferroelectric material (1,3-dicyclohexylimidazole)₂MnCl₄ (DHIMC). Thermogravimetric analysis (TGA) was used to measure the mass change of the material at a measurement rate of 20 K min^-1 from room temperature to 900 K, and we found that this material has good thermostability, which is up to 383 K. Meanwhile, UV-vis measurements showed that it is also a fluorescent material emitting a strong green fluorescence at the wavelength of 525 nm. The ferroelectricity of the crystal was determined by two different methods: the Sawyer-Tower method and the double-wave method (DWM). Particularly, the single crystal experiences a phase transition from the ferroelectric phase to the paraelectric phase during the heating/cooling process at 318 K/313 K and the space group changes from P1̄ (centrosymmetric) to P1 (non-centrosymmetric). This work will enrich multifunctional luminescent ferroelectric materials and their application in display and sensing.

Baseline white matter function predicts short-term treatment response in first-episode schizophrenia

BACKGROUND AND PURPOSE

The detection and characterization of functional activities in the gray matter of schizophrenia (SZ) have been widely explored. However, the relationship between resting-state functional signals in the white matter of first-episode SZ and short-term treatment response remains unclear.

METHODS

Thirty-six patients with first-episode SZ and 44 matched healthy controls were recruited in this study. Patients were classified as nonresponders and responders based on response to antipsychotic medication during a single hospitalization. The fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), and functional connectivity (FC) of white matter were calculated. The relationships between functional changes and clinical features were analyzed. In addition, voxel-based morphometry was performed to analyze the white matter volume.

RESULTS

One-way analysis of variance showed significant differences of fALFF and ReHo in the left posterior thalamic radiation and left cingulum (hippocampus) in the patient group, and the areas were regarded as seeds. The FC was calculated between seeds and other white matter networks. Compared with responders, nonresponders showed significantly increased FC between the left cingulum (hippocampus) and left posterior thalamic radiation, splenium of corpus callosum, and left tapetum, and were associated with the changes of clinical assessment. However, there was no difference in white matter volume between groups.

CONCLUSION

Our work provides a novel insight that psycho-neuroimaging-based white matter function holds promise for influencing the clinical diagnosis and treatment of SZ.

[A case of pulmonary aspergillus infection in underground coal mine workers]

The underground environment is dark and humid, and it is easy to breed pathogenic microorganisms. A lump in the right lung of a coal mine underground transport worker was found druing occupational health examination. CT examination showed that the lump was located in the posterior segment of the upper lobe of the right lung, with point strip calcification, liquefaction necrosis, and proximal bronchial stenosis and occlusion. MRI examination FS-T(2)WI and DWI showed "target sign", annular low signal around the central high signal, and low mixed signal around the periphery, and annular high signal in the isosignal lesions on T(1)WI. Then the pulmonary aspergillus infection was confirmed by pathology.

Piezo-Activated Atomic-Thin Molybdenum Disulfide/MXene Nanoenzyme for Integrated and Efficient Tumor Therapy via Ultrasound-Triggered Schottky Electric Field

Monolayer molybdenum disulfide (MoS₂ ) nanoenzymes exhibit a piezoelectric polarization, which generates reactive oxygen species to inactivate tumors under ultrasonic strain. However, its therapeutic efficiency is far away from satisfactory, due to stackable MoS₂ , quenching of piezo-generated charges, and monotherapy. Herein, chitosan-exfoliated monolayer MoS₂ (Ch-MS) is composited with atomic-thin MXene, Ti₃ C₂ (TC), to self-assemble a multimodal nanoplatform, Ti₃ C₂ -Chitosan-MoS₂ (TC@Ch-MS), for tumor inactivation. TC@Ch-MS not only inherits piezoelectricity from monolayer MoS₂ , but also maintains remarkable stability. Intrinsic metallic MXene combines with MoS₂ to construct an interfacial Schottky heterojunction, facilitating the separation of electron-hole pairs and endowing TC@Ch-MS increase-sensitivity magnetic resonance imaging responding. Schottky interface also leads to peroxidase mimetics with excellent catalytic performance toward H₂ O₂ in the tumor microenvironment under mechanical vibration. TC@Ch-MS possesses the superior photothermal conversion efficiency than pristine TC under near-infrared ray illumination, attributed to its enhanced interlaminar conductivity. Meanwhile, TC@Ch-MS realizes optimized efficiency on tumor apoptosis with immunotherapy. Therefore, TC@Ch-MS achieves an integrated diagnosis and multimodal treatment nanoplatform, whereas the toxicity to normal tissue cells is negligible. This work may shed fresh light on optimizing the piezoelectric materials in biological applications, and also give prominence to the significance of intrinsic metallicity in MXene.

[Cognition and reflection on the "lateral ligament of rectum"]

As total mesorectal excision (TME) for rectal cancer is widely carried out in China, lateral ligament of rectum, as an important anatomical structure of the lateral rectum with certain anatomical value and clinical significance, has been the focus of attention. In this paper, by comparing and analyzing the characteristics about ligaments of the abdomen and pelvis, reviewing the membrane anatomy and the theory of primitive gut rotation, and combining clinical observations and histological studies, the author came to a conclusion that lateral ligament of rectum does not exist, but is only a relatively dense space on the rectal side accompanied by numerous tiny nerve plexuses and small blood vessels penetrating through it.

[Progress in clinical diagnosis and treatment of gallbladder cancer]

Due to the lack of effective early diagnosis and treatment, gallbladder cancer(GBC) remains a malignant tumor with extremely high malignancy and poor prognosis. Therefore, high quality studies are required to break through the bottleneck in GBC diagnosis and treatment. This article reviewed the domestic and foreign GBC research published in 2021, presenting a comprehensive summary of the important advances in the field of clinical diagnosis and treatment. Latest epidemiological data and risk factors, emerging diagnostic methods of peripheral blood laboratory tests and imaging, new pathologic classification system, hot topics and controversies of surgical treatment as well as the dynamics of systemic treatment of GBC are reviewed in the article. The present findings may contribute to a more efficient means of diagnosis and treatment for GBC and hold the promise of improved outcomes for patients with GBC.

Manipulating the carrier concentration and phase transition via Nb content in SrTiO3

SrTiO3 is a model of the perovskite-like compounds for structural transition which inducing the intriguing physical properties around the critical phase transition temperature TAFD (antiferrodistortive, abbrev. as AFD). Here we report that the electrical transport behavior is a new way to quantify Nb concentration for Nb-doped SrTiO3. The lattice parameter (c), phase transition temperature (TAFD), and the carrier concentration (n) of SrTiO3 may be manipulated by niobium doping. TAFD increases with increasing the niobium content in a rate of about 30 K per (wt%, i.e. niobium element's weight verses total weight) niobium and n in a rate of about 2.5 [Formula: see text] 1020/cm3 per (wt%) niobium.

Large dielectric switch effects induced by an order-disorder transformation in cyclopropylamine perchlorate crystals

Solid-state crystals with two distinct dielectric states can be a physical practice in binary-based technologies. A large dielectric switch effect up to 10³ caused by an order-disorder structural phase transition is found in cyclopropylamine perchlorate (CPA-ClO₄) crystals at temperatures around 230 K (T_c) and 220 K (T'_c). Large dielectric switch effects here can be compared to that of the famous ceramic oxide dielectrics. As far as we know, this is the highest dielectric switch effect in simple organic salt crystals and organic-metal compounds so far. If the phase transition temperature can be adjusted by molecular manipulation, one of the most promising candidates for technological applications may emerge in the future.

Neuroimaging-based brain-age prediction of first-episode schizophrenia and the alteration of brain age after early medication

BACKGROUND

Neuroimaging- and machine-learning-based brain-age prediction of schizophrenia is well established. However, the diagnostic significance and the effect of early medication on first-episode schizophrenia remains unclear.

AIMS

To explore whether predicted brain age can be used as a biomarker for schizophrenia diagnosis, and the relationship between clinical characteristics and brain-predicted age difference (PAD), and the effects of early medication on predicted brain age.

METHOD

The predicted model was built on 523 diffusion tensor imaging magnetic resonance imaging scans from healthy controls. First, the brain-PAD of 60 patients with first-episode schizophrenia, 60 healthy controls and 21 follow-up patients from the principal data-set and 40 pairs of individuals in the replication data-set were calculated. Next, the brain-PAD between groups were compared and the correlations between brain-PAD and clinical measurements were analysed.

RESULTS

The patients showed a significant increase in brain-PAD compared with healthy controls. After early medication, the brain-PAD of patients decreased significantly compared with baseline (P < 0.001). The fractional anisotropy value of 31/33 white matter tract features, which related to the brain-PAD scores, had significantly statistical differences before and after measurements (P < 0.05, false discovery rate corrected). Correlation analysis showed that the age gap was negatively associated with the positive score on the Positive and Negative Syndrome Scale in the principal data-set (r = -0.326, P = 0.014).

CONCLUSIONS

The brain age of patients with first-episode schizophrenia may be older than their chronological age. Early medication holds promise for improving the patient's brain ageing. Neuroimaging-based brain-age prediction can provide novel insights into the understanding of schizophrenia.

An Organic-Inorganic Hybrid Pyrrolidinium Ferroelectric Based on Solvent Selective Effect

Organic-inorganic hybrid ferroelectrics (OIHFs) have fueled enormous interest benefiting from their less environmental pollution, performance-tailored functionality, low product costs as well as tunability of structures. However, the lack of material synthesis approaches and diverse targeted molecular design is a stumbling block for designing novel OIHFs rationally. Here, we report a unique organic-inorganic hybrid ferroelectric (3,3-difluoropyrrolidine)₂CdCl₄ 1 and another novel nonferroelectric crystal (3,3-difluoropyrrolidine)₂Cd₂Cl₆ 2 by changing various crystallization solvents. Significantly, 1 presents a ferroelectric phase transition behavior at ∼367 K, and the distinct symmetry breaking, i.e., mmmFm, sets up a biaxial ferroelectric with four equivalent directions of polarization, which has a P_r ∼ 0.77 μC/cm². Systematic studies prove that ferroelectricity can be ascribed to the synergistic effects of the distortion of the inorganic anion skeleton and the ordering of organic cations. This work reveals the potential of constructing novel ferroelectrics based on the solvent selective effect and pyrrolidinium as organic cations.

The Association Between Lentiform Nucleus Function and Cognitive Impairments in Schizophrenia

Introduction: Cognitive decline is the core schizophrenia symptom, which is now well accepted. Holding a role in various aspects of cognition, lentiform nucleus (putamen and globus pallidus) dysfunction contributes to the psychopathology of this disease. However, the effects of lentiform nucleus function on cognitive impairments in schizophrenia are yet to be investigated.

Objectives: We aim to detect the fractional amplitude of low-frequency fluctuation (fALFF) alterations in patients with schizophrenia, and examine how their behavior correlates in relation to the cognitive impairments of the patients.

Methods: All participants underwent magnetic resonance imaging (MRI) and cognitive assessment (digit span and digit symbol coding tests). Screening of brain regions with significant changes in fALFF values was based on analysis of the whole brain. The data were analyzed between Jun 2020 and Mar 2021. There were no interventions beyond the routine therapy determined by their clinicians on the basis of standard clinical practice.

Results: There were 136 patients (75 men and 61 women, 24.1 ± 7.4 years old) and 146 healthy controls (82 men and 64 women, 24.2 ± 5.2 years old) involved in the experiments seriatim. Patients with schizophrenia exhibited decreased raw scores in cognitive tests (p < 0.001) and increased fALFF in the bilateral lentiform nuclei (left: 67 voxels; x = −24, y = −6, z = 3; peak t-value = 6.90; right: 16 voxels; x = 18, y = 0, z = 3; peak t-value = 6.36). The fALFF values in the bilateral lentiform nuclei were positively correlated with digit span-backward test scores (left: r = 0.193, p = 0.027; right: r = 0.190, p = 0.030), and the right lentiform nucleus was positively correlated with digit symbol coding scores (r = 0.209, p = 0.016).

Conclusion: This study demonstrates that cognitive impairments in schizophrenia are associated with lentiform nucleus function as revealed by MRI, involving working memory and processing speed.

Elaboration of a Radiomics Strategy for the Prediction of the Re-positive Cases in the Discharged Patients With COVID-19

Objective: A considerable part of COVID-19 patients were found to be re-positive in the SARS-CoV-2 RT-PCR test after discharge. Early prediction of re-positive COVID-19 cases is of critical importance in determining the isolation period and developing clinical protocols. Materials and Methods: Ninety-one patients discharged from Wanzhou Three Gorges Central Hospital, Chongqing, China, from February 10, 2020 to March 3, 2020 were administered nasopharyngeal swab SARS-CoV-2 tests within 12-14 days, and 50 eligible patients (32 male and 18 female) with completed data were enrolled. Average age was 48 ± 11.5 years. All patients underwent non-enhanced chest CT on admission. A total of 568 radiomics features were extracted from the CT images, and 17 clinical factors were collected based on the medical record. Student's t-test and support vector machine-based recursive feature elimination (SVM-RFE) method were used to determine an optimal subset of features for the discriminative model development. Results: After Student's t-test, 62 radiomics features showed significant inter-group differences (p < 0.05) between the re-positive and negative cases, and none of the clinical features showed significant differences. These significant features were further selected by SVM-RFE algorithm, and a more compact feature subset containing only two radiomics features was finally determined, achieving the best predictive performance with the accuracy and area under the curve of 72.6% and 0.773 for the identification of the re-positive case. Conclusion: The proposed radiomics method has preliminarily shown potential in identifying the re-positive cases among the recovered COVID-19 patients after discharge. More strategies are to be integrated into the current pipeline to improve its precision, and a larger database with multi-clinical enrollment is required to extensively verify its performance.

Thalamus Radiomics-Based Disease Identification and Prediction of Early Treatment Response for Schizophrenia

Background

Emerging evidence suggests structural and functional disruptions of the thalamus in schizophrenia, but whether thalamus abnormalities are able to be used for disease identification and prediction of early treatment response in schizophrenia remains to be determined. This study aims at developing and validating a method of disease identification and prediction of treatment response by multi-dimensional thalamic features derived from magnetic resonance imaging in schizophrenia patients using radiomics approaches.

Methods

A total of 390 subjects, including patients with schizophrenia and healthy controls, participated in this study, among which 109 out of 191 patients had clinical characteristics of early outcome (61 responders and 48 non-responders). Thalamus-based radiomics features were extracted and selected. The diagnostic and predictive capacity of multi-dimensional thalamic features was evaluated using radiomics approach.

Results

Using radiomics features, the classifier accurately discriminated patients from healthy controls, with an accuracy of 68%. The features were further confirmed in prediction and random forest of treatment response, with an accuracy of 75%.

Conclusion

Our study demonstrates a radiomics approach by multiple thalamic features to identify schizophrenia and predict early treatment response. Thalamus-based classification could be promising to apply in schizophrenia definition and treatment selection.

[Pathogens' distribution and changes of antimicrobial resistance in the bile of acute biliary tract infection patients]

Objective: To investigate the pathogens' distribution and antimicrobial resistance in the bile of acute biliary tract infection patients. Methods: The data of bile bacterial culture and drug sensitivity test of 223 acute biliary tract infection patients who underwent gallbladder puncture or endoscopic retrograde cholangiopancreatography drainage from July 2009 to July 2019 were analyzed retrospectively at Department of General Surgery,Xinhua Hospital,Affiliated to Shanghai Jiao Tong University School of Medicine.There were 141 males and 82 females with age of 67.3 years(range:28 to 93 years).Three to five milliliter of bile was extracted from each patient and sent to the laboratory for bacterial culture,identification and drug sensitivity test.The patients were divided into two groups according to the visiting time: the former group (n=124) was admitted from July 2009 to July 2014,and the latter group(n=99) was admitted from August 2014 to July 2019.The distribution of pathogenic bacteria and the changing trend of drug resistance rate of common bacteria in the two groups were compared.The results of drug sensitivity test were analyzed by WHONET software provided by WHO bacterial surveillance network.The drug resistance rates in different time periods were compared by χ² test. Results: In this study,there were 147 cases of acute cholangitis and 76 cases of acute cholecystitis.A total of 376 strains of pathogenic bacteria were cultured.Among them,98 strains(26.1%) were gram-positive bacteria,269 strains(71.5%) were gram-negative bacteria and 9 strains(2.4%) were fungi.The top three gram-positive bacteria were Enterococcus faecium (49.0%,48/98),Enterococcus faecalis(20.4%,20/98),and Enterococcus luteus(7.1%,7/98).The top 5 gram-negative bacteria were Escherichia coli(33.5%,90/269),Klebsiella pneumoniae(13.8%,37/269),Pseudomonas aeruginosa(13.0%,35/269),Acinetobacter baumannii (12.6%,34/269),and Enterobacter cloacae(4.8%,13/269).From 2009 to 2019,there was no significant change in the proportion of gram-positive bacteria (former group vs. latter group: 25.3% vs. 28.2%) and gram-negative bacteria(former group vs.latter group: 74.7% vs. 71.8%) in the bile of patients with acute biliary tract infection.Gram-positive bacteria were mainly Enterococci(85.7%,84/98) and gram-negative bacteria were Escherichia coli(33.5%,90/269).Acinetobacter baumannii accounted for 7.8%(11/142) of gram-negative bacteria in the former group and 18.1%(23/127) in the latter group,an increase of 10.3% over previous five years.Pseudomonas aeruginosa had a downward trend,16.9% in the former group(24/142) and 8.7% in the latter group (11/127),the proportion decreased by 8.2%,and the other changes were not significant.The drug resistance rates of common gram-positive bacteria were relatively stable,and the drug resistance rates of Enterococcus faecium to many antibiotics were higher than those of Enterococcus faecalis.The resistance rates of gram-negative bacteria to most antibiotics showed an upward trend,among which Klebsiella pneumoniae showed an upward trend to most of antibiotics(former group: 0/15－4/13, latter group: 55.0%－70.0%; χ²=3.996－16.942, P=0.000－0.046).The drug resistance rates of Acinetobacter baumannii was generally higher,but there were no significant changes in the drug resistance rates of Acinetobacter baumannii between the two groups.The drug resistance rates of Pseudomonas aeruginosa to most antibiotics increased,and the overall drug resistance rates of Escherichia coli were stable and showed a slight upward trend. Conclusions: The main pathogens in bile of patients with acute biliary tract infection are gram-negative bacteria.The constituent ratio of various gram-negative bacteria had no significant change from 2009 to 2019,but the drug resistance rates shows an upward trend.Among the gram-negative bacteria, Escherichia coli is the most important pathogen,and the proportion has no significant change.The proportion of Acinetobacter baumannii in the former group was significantly higher than that in the former group.And the proportion of Pseudomonas aeruginosa has a decreased trend.

Baseline structural and functional magnetic resonance imaging predicts early treatment response in schizophrenia with radiomics strategy

Multimodal neuroimaging features provide opportunities for accurate classification and personalized treatment options in the psychiatric domain. This study aimed to investigate whether brain features predict responses to the overall treatment of schizophrenia at the end of the first or a single hospitalization. Structural and functional magnetic resonance imaging (MRI) data from two independent samples (N = 85 and 63, separately) of schizophrenia patients at baseline were included. After treatment, patients were classified as responders and non-responders. Radiomics features of gray matter morphology and functional connectivity were extracted using Least Absolute Shrinkage and Selection Operator. Support vector machine was used to explore the predictive performance. Prediction models were based on structural features (cortical thickness, surface area, gray matter regional volume, mean curvature, metric distortion, and sulcal depth), functional features (functional connectivity), and combined features. There were 12 features after dimensionality reduction. The structural features involved the right precuneus, cuneus, and inferior parietal lobule. The functional features predominately included inter-hemispheric connectivity. We observed a prediction accuracy of 80.38% (sensitivity: 87.28%; specificity 82.47%) for the model using functional features, and 69.68% (sensitivity: 83.96%; specificity: 72.41%) for the one using structural features. Our model combining both structural and functional features achieved a higher accuracy of 85.03%, with 92.04% responder and 80.23% non-responders to the overall treatment to be correctly predicted. These results highlight the power of structural and functional MRI-derived radiomics features to predict early response to treatment in schizophrenia. Prediction models of the very early treatment response in schizophrenia could augment effective therapeutic strategies.

[Analysis of treatment modalities and prognosis of patients with gallbladder cancer in China from 2010 to 2017]

Objective: To evaluate the clinical characteristics and prognosis of gallbladder cancer (GBC) patients in China. Methods: This retrospective multicenter cohort study enrolled 3 528 consecutive GBC patients diagnosed between January 2010 to December 2017 in 15 hospitals from 10 provinces. There were 1 345 (38.12%) males and 2 183 (61.88%) females.The age of diagnosis was (63.7±10.8) years old (range: 26 to 99 years old) .There were 213 patients (6.04%) in stage 0 to Ⅰ, whereas 1 059 (30.02%) in stage Ⅱ to Ⅲ, 1 874 (53.12%) in stage Ⅳ, and 382 (10.83%) unavailable. Surgery was performed on 2 255 patients (63.92%) . Three hundred and thirty-six patients received chemotherapy or radiotherapy (9.52%; of which 172 were palliative); 1 101 (31.21%) received only supportive treatment.The patient source, treatment and surgery, pathology, concomitant gallstone, and prognosis were analyzed. Results: Among the 3 528 GBC patients, 959 (27.18%) were from East China, 603 (17.09%) from East-North China, 1 533 (43.45%) from Central China, and 433(12.27%) from West China. Among the 1 578 resectable tumor, 665 (42.14%) underwent radical surgery, 913 (57.86%) underwent surgery that failed to follow the guidelines.Eight hundred and ninety-one (56.46%) patients were diagnosed before surgery, 254 (16.10%) during surgery, and 381 (24.14%) after surgery (time point of diagnosis couldn't be determined in 52 patients) .Among the 1 578 patients with resectable tumor, 759 (48.10%) had concomitant gallstone.Among the 665 patients underwent radical surgery, 69 (10.4%) showed positive resection margin, 510 (76.7%) showed negative resection margin, and 86 (12.9%) unreported margin status.The 5-year overall survival rate (5yOS) for the 3 528-patient cohort was 23.0%.The 5yOS for patients with resectable tumor was 39.6%, for patients with stage ⅣB tumor without surgery was 5.4%, and for patients with stage ⅣB tumor underwent palliative surgery was 4.7%. Conclusions: More than half GBC patients in China are diagnosed in stage Ⅳ.Curative intent surgery is valuable in improving prognosis of resectable GBC.The treatment of GBC needs further standardization.Effective comprehensive treatment for GBC is in urgent need.

Unraveling the Topological Phase of ZrTe_{5} via Magnetoinfrared Spectroscopy

For materials near the phase boundary between weak and strong topological insulators (TIs), their band topology depends on the band alignment, with the inverted (normal) band corresponding to the strong (weak) TI phase. Here, taking the anisotropic transition-metal pentatelluride ZrTe_{5} as an example, we show that the band inversion manifests itself as a second extremum (band gap) in the layer stacking direction, which can be probed experimentally via magnetoinfrared spectroscopy. Specifically, we find that the band anisotropy of ZrTe_{5} features a slow dispersion in the layer stacking direction, along with an additional set of optical transitions from a band gap next to the Brillouin zone center. Our work identifies ZrTe_{5} as a strong TI at liquid helium temperature and provides a new perspective in determining band inversion in layered topological materials.

[The pattern and regulatory mechanism of mammalian diphyodont tooth replacement]

Although the dental lamina of permanent teeth in human being has been developed as early as the embryo stage, the replacement of the deciduous teeth by permanent teeth does not take place untill the age of 6 to 12 years old. The molecular mechanism of the initiation of permanent teeth is still unclear. The rodent species are usually used for the tooth development research in the past. However, this animal model is not suitable for the tooth replacement study because of the absence of tooth replacement in rodents. After 10 years of efforts, our team has established the animal model of miniature pig for tooth replacement research. Using this model, we firstly defined the spatiotemporal pattern of teeth replacement. In the further mechanism research, results showed that the growing rate of the deciduous teeth was faster than that of the surrounding alveolar bone, and biomechanical stress inside mandible was generated due to the fast growth of deciduous teeth. The stress might up-regulate the signal of Runt-related transcription factor 2 (RUNX2)-Wnt pathway in the mesenchyme between the deciduous and permanent teeth, sustain the successional dental lamina at the resting stage and inhibit the development of permanent teeth. A similar expression pattern was also found in the mesenchyme between the deciduous and permanent teeth in human. Our findings demonstrated that the eruption of deciduous tooth released the stress inside mandible, thus induced the "Wnt translocation" from the mesenchyme into the epithelium of permanent counterpart and therefore initiated the development of permanent teeth. The underlying mechanism of the replacement of deciduous teeth by permanent teeth is the regulation of biomechanical stress throughout the initiation process. Based on the findings, we proposed the theory of "biomechanical stress regulation of the tooth replacement" . The replacement pattern and regulatory mechanism provide a scientific foundation for the organ development and regeneration by regulating the biomechanical stress and Wnt pathway in the future.

[Laparoscopic gastroduodenostomy with manual suture for Billroth Ⅰ anastomosis: a report of 36 cases]

Objective: To examine the clinical efficiency of laparoscopic gastroduodenostomy with BillrothⅠanastomosis with manual suture. Methods: The clinic data of 36 patients with gastric cancer who underwent laparoscopic gastroduodenostomy with Billroth Ⅰ anastomosis from November 2017 to September 2019 in Department of Gastrointestinal and Pancreatic Surgery, Zhejiang Provincial People's Hospital were analyzed retrospectively.There were 22 males and 14 females, aged (64.3±9.3) years(range: 43 to 80 years), underwent complete laparoscopic gastroduodenostomy. The laparoscopic manual suture was used for Billroth Ⅰ anastomosis. Results: All the laparoscopic radical gastrectomy and manual suturing gastroduodenostomy were successfully performed. The operation time was (226.7±40.4) minutes (range: 180 to 320 minutes), including (24.8±7.1) minutes (range: 15 to 48 minutes) for gastroduodenostomy.There was (3.8±0.9) days (range: 2 to 6 days) for anal exhaust, (5.7±2.0) days (range: 3 to 13 days) for extubation of gastric tube, and (10.3±3.1) days (range: 7 to 19 days) for hospitalization. There was no death in perioperative period. Postoperative pathological report showed 3 cases of highly differentiated adenocarcinoma, 5 cases of moderately differentiated adenocarcinoma, 22 cases of poorly differentiated adenocarcinoma and 6 cases of signet ring cell carcinoma, including 27 cases in T1 stage and 9 cases in T2 stage. The number of lymph nodes harvested was 36.4±8.9 (range: 23 to 60). Lymph node metastasis was positive in 7 cases and negative in 29 cases. TNM stage included 24 cases in ⅠA stage, 8 cases in ⅠB stage and 4 cases in Ⅱ stage. After the operation, the upper digestive tract radiography showed that the anastomosis opening was unobstructed without complications such as anastomotic stenosis. Conclusion: Laparoscopic gastroduodenostomy with Billroth Ⅰ anastomosis with manual suture is safe and feasible, has a good short-term effect.

Modulating the electronic and optical properties for SrTiO3/LaAlO3 bilayers treated as the 2D materials by biaxial strains

The emerging two-dimensional (2D) materials such as graphene have opened the door to industrial applications. Here, we consider the oxide perovskite monolayer of SrTiO₃ (STO), LaAlO₃ (LAO) and their heterostructures as the 2D transitional metal system. Results show that a band-gap transition from indirect to direct occurs when the separated monolayer STO (indirect band gap of 3.210 eV), and LAO (indirect band gap of 4.024 eV), form the heterostructures (direct band gap of 2.976 eV). The obtained bandgap for the stable bilayers may effectively be modulated by biaxial strains from  -12% to 8%. With 12% compressive biaxial strain, the band gap reduces to be 0.23 eV. The optical properties for the stable bilayers are also tuned by the biaxial strain. When the strain increases from compressive strain to tensile strain, the strongest peak of the imaginary part of dielectric function red shifts to lower energy. In comparing with the monolayer STO and LAO, the elastic property enhances obviously for the stable heterostructure, suggesting the heterostructure can be more stable freestanding or may be applied in device fabrications.

Neuroanatomical Features That Predict Response to Electroconvulsive Therapy Combined With Antipsychotics in Schizophrenia: A Magnetic Resonance Imaging Study Using Radiomics Strategy

OBJECTIVE

Neuroimaging-based brain signatures may be informative in identifying patients with psychosis who will respond to antipsychotics. However, signatures that inform the electroconvulsive therapy (ECT) health care professional about the response likelihood remain unclear in psychosis with radiomics strategy. This study investigated whether brain structure-based signature in the prediction of ECT response in a sample of schizophrenia patients using radiomics approach.

METHODS

This high-resolution structural magnetic resonance imaging study included 57 patients at baseline. After ECT combined with antipsychotics, 28 and 29 patients were classified as responders and non-responders. Features of gray matter were extracted and compared. The logistic regression model/support vector machine (LRM/SVM) analysis was used to explore the predictive performance.

RESULTS

The regularized multivariate LRM accurately discriminated responders from non-responders, with an accuracy of 90.91%. The structural features were further confirmed in the validating data set, resulting in an accuracy of 87.59%. The accuracy of the SVM in the training set was 90.91%, and the accuracy in the validation set was 91.78%.

CONCLUSION

Our results support the possible use of structural brain feature-based radiomics as a potential tool for predicting ECT response in patients with schizophrenia undergoing antipsychotics, paving the way for utilization of markers in psychosis.

High-Temperature Molecular Ferroelectric Tris(2-hydroxyethyl) Ammonium Bromide with Dielectric Relaxation

We obtained one new molecular ferroelectric material tris(2-hydroxyethyl) ammonium bromide (TAB) that crystallizes in aqueous solution at room temperature with a space group of R3m which belongs to ten polar space groups. There is a paraelectric-to-ferroelectric phase transition at 424 K (from hexagonal R3̅m to hexagonal R3m phase). Such a high transition temperature is close to that of diisopropylamine bromide (426 K) and higher than that of many other molecular ferroelectrics, such as triethylmethylammonium tetrabromoferrate(III) (360 K); some of the organic-inorganic perovskite ferroelectrics, such as (cyclohexylammonium)₂PbBr₄ (363 K); and some inorganic ferroelectrics, including BaTiO₃ (393 K). The saturated polarization and the coercive field of TAB measured from the ferroelectric hysteresis loop are about 0.54 μC·cm^-2 and 0.62 kV/cm, respectively. Given its superior performance, including high phase transition temperature, room-temperature ferroelectricity, small coercive electric field, and adjustable ladder-shaped dielectric constant, TAB will have many potential applications.

Ferroelectricity of the Orthorhombic and Tetragonal MAPbBr3 Single Crystal

Hybrid organic-inorganic halide perovskites (HOIPs) MAPbBr₃ and their ramifications have emerged because of the photovoltaic, optical, and other fascinating performances of HOIPs in recent years. However, many intrinsic properties, such as crystal structure and ferroelectricity, are still controversial. In this work, the ferroelectricity of the orthorhombic and tetragonal MAPbBr₃ single crystal was confirmed through the dielectric behavior versus bias electric field ε( E), the temperature-dependent pyroelectric current with positive/negative poling, and the positive-up-negative-down (PUND) measurements. The electric field dependence of dielectric constant curves shows a butterfly type shape in the orthorhombic and tetragonal phase. The pyroelectric current shows two maxima at 155 and 245 K, corresponding to ferroelectric-ferroelectric and ferroelectric-paraelectric phase transitions, respectively. In particular, the direction of the pyroelectric current can be reversed by a positive or negative poling electric field, which is the assertive evidence of ferroelectricity. The PUND measurements act as the most convincing proof of the ferroelectricity of the MAPbBr₃ single crystal. This work reports new evidence of the ferroelectric properties of the MAPbBr₃ single crystal, which provides the intrinsic property when considering their high power conversion efficiencies.

[The role of anatomical hepatectomy in the treatment of intrahepatic cholangiocarcinoma]

Objective: To evaluate the role of anatomical hepatectomy in the treatment of intrahepatic cholangiocarcinoma. Methods: The cases of intrahepatic cholangiocarcinoma who received curative surgery in two hospitals from 2010 to 2015 were analyzed retrospectively. Among the 98 patients enrolled in this study, 55 were male and 43 were female. The median age was 61 years. According to receiving anatomical hepatectomy or not, the 98 cases were divided into two groups: non-anatomical hepatectomy(n=30) and anatomical hepatectomy(n=68). The surgical results were compared between the two groups.Survival curves were plotted by the Kaplan-Meier method and compared by the log-rank test. The influence of each prognostic factor identified by univariate analysis was multivariate analysis by Cox's proportional hazard regression. Results: The duration of surgery was significantly prolonged in the anatomical hepatectomy group((196.4±94.9)minutes vs. (166.2±65.7)minutes, P=0.027), while there was no significant difference in terms of other surgical results such as intraoperative blood transfusion, postoperative morbidity and mortality rate. Compared to non-anatomical hepatectomy, anatomical hepatectomy significantly improved long-term survival results(14 months vs. 11 months)(χ²=4.641, P=0.031). Single variable analysis indicated that tumor differentiation, tumor numbers, T stage, N stage, anatomical hepatectomy and adjuvant therapy significantly affected overall survival. Multivariate analysis demonstrated that tumor numbers(HR=0.522, 95% CI: 0.259-0.974, P=0.042) and anatomical hepatectomy(HR=1.858, 95%CI: 1.092-3.161, P=0.022) were two independent prognostic factors for overall survival. Conclusion: Compared to non-anatomical hepatectomy, anatomical hepatectomy performed for intrahepatic cholangiocarcinoma is not only safe but also beneficial for long-term survival.

[Diagnosis and treatment for unexpected gallbladder carcinoma(a retrospective study of 45 cases)]

Objective: To investigate the rationale for appropriate diagnostic methods and treatment protocols for unexpected gallbladder carcinoma(UGC). Methods: The clinical and pathological data of 45 patients with UGC admitted at Department of General Surgery, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine,from January 2008 to December 2017 were retrospectively collected and analyzed.There were 11 males(28.9%) and 34 females(71.1%),aged 68 years(range:27 to 68 years).And there were 20 cases who aged above 70 years. Twenty-four cases were diagnosed preoperatively as cholecystolithiasis plus chronic cholecystitis.Ten cases were diagnosed preoperatively as cholecystolithiasis plus actue cholecystitis.Six cases were diagnosed preoperatively as cholecystolithiasis plus choledocholith.Six cases were admitted because of gallbladder polyp and 1 case was admitted because of gallbladder adenomyomatosis. Results: Thirty-four patients with UGC received radical surgery.Among them,11 patients experienced postoperative complication and no posterative mortality occoured during hospital stay.Thirteen patients were diagnosed with T1b UGC, the harvested lymph node of Nx, N0, N1 and N2 was 2, 9, 1 and 1, respectively.In addition, 2 cases were identified to have local-regional tumor recurrence during our rescue radical surgery.The median overall survival time of the patients who did not receive radical surgery was 7 months(range:2-56 months).Nevertheless,the median overall survival time for patients diagnosed with T1, T2 and T3 tumors who received radical surgery, was 41 months(range: 19-82 months), 33.5 months(range: 31-36 months) and 17 months(range: 7-46 months), respectively. Conclusions: For patients with UGC, rescue radical surgery can achieve a better survival time.Furhtermore, our experience proved that rescue radical surgery for UGC is safe and feasible.Therefore,rescue radical surgery should be performed in patients with diagnose with UGC especially those T1b patients.

[Effects of hypertonic sodium saline resuscitation on the liver damage of rats at early stage of severe scald]

Objective: To explore the effects of hypertonic sodium saline (HSS) resuscitation on the liver damage of rats at early stage of severe scald. Methods: Fifty-six SD rats were divided into sham injury group (SI, n=8), lactated Ringer's solution group (LRS, n=24), and group HSS (n=24) according to the random number table. Rats in group SI were sham injured without resuscitation, while rats in the other two groups were reproduced deep partial-thickness to full-thickness scald model with 30% total body surface area on the back. Rats in group LRS were resuscitated with LRS, while rats in group HSS were resuscitated with 300 mmol/L sodium ion solution according to the Parkland formula. Blood of abdominal aorta and liver of 8 rats in group SI immediately post injury and in the other two groups at post injury hour (PIH) 2, 8, and 24 respectively were collected. Then liver water content was determined by dry-wet weight method. Serum content of alanine aminotransferase (ALT) and aspartate transaminase (AST) was detected by automatic biochemical analyzer. Serum content of tumor necrosis factor α (TNF-α), interleukin-1 (IL-1), and high mobility group box 1 (HMGB1) was determined by enzyme-linked immunosorbent assay. Liver content of malondialdehyde (MDA) and superoxide dismutase (SOD) was detected by ultraviolet spectrophotometer. Pathologic changes of liver were observed by HE staining. Data were processed with one-way analysis of variance and SNK test. Results: (1) At PIH 2, 8, and 24, liver water content of rats in group LRS was higher than that in group SI and group HSS (P<0.05 or P<0.01). (2) At PIH 2, serum ALT content of rats in the three groups was similar (with P values above 0.05). At PIH 8 and 24, serum ALT content of rats in group HSS and group LRS was higher than that in group SI (P<0.05 or P<0.01), and serum ALT content of rats in group HSS was lower than that in group LRS (with P values below 0.01). At PIH 2, 8, and 24, serum AST content of rats in group HSS and group LRS was higher than that in group SI (with P values below 0.01). At PIH 2 and 8, serum AST content of rats in group HSS was lower than that in group LRS (P<0.05 or P<0.01). (3) At PIH 2 and 8, serum TNF-α content of rats in group LRS was (123±39) and (153±38) pg/mL respectively, higher than that in group SI [(60±18) pg/mL] and group HSS [(85±10) and (94±16) pg/mL respectively, with P values below 0.01]. At PIH 8, serum TNF-α content of rats in group HSS was higher than that in group SI (P<0.05). At PIH 24, serum TNF-α content of rats in the three groups was similar (with P values above 0.05). At PIH 2, 8, and 24, serum IL-1 content of rats in group LRS was (122±35), (141±30), and (122±31) pg/mL respectively, and that in group HSS was (80±12), (93±15), and (80±11) pg/mL respectively, all higher than that in group SI [(40±17) pg/mL, with P values below 0.01]; serum IL-1 content of rats in group HSS was lower than that in group LRS (with P values below 0.01). At PIH 2, serum HMGB1 content of rats in the three groups was similar (with P values above 0.05). At PIH 8 and 24, serum HMGB1 content of rats in group LRS was (0.386±0.146) and (0.590±0.188) ng/mL respectively, higher than that in group SI [(0.050±0.027) ng/mL] and group HSS [(0.143±0.038) and (0.309±0.095) ng/mL respectively, with P values below 0.01]. At PIH 24, serum HMGB1 content of rats in group HSS was higher than that in group SI (P<0.01). (4) At PIH 2, 8, and 24, liver MDA content of rats in group HSS and group LRS was higher than that in group SI and their liver SOD content was lower than that in group SI (with P values below 0.01); liver MDA content of rats in group HSS was lower than that in group LRS and their liver SOD content was higher than that in group LRS (with P values below 0.01). (5) Compared with those of rats in group SI, liver cells of rats in group LRS showed massive steatosis at each time point, and liver cell-edema appeared at PIH 8 and 24; while liver cells of rats in group HSS showed little steatosis only at PIH 8 and 24, and the liver cell-edema never appeared. Conclusions: Compared with LRS, HSS resuscitation can alleviate liver injury of rats at the early stage of severe scald through relieving inflammatory mediators and reducing degree of oxidative stress, etc.

[Method and significance of specimens standardized pathological treatment in pancreaticoduodenectomy for pancreatic head cancer]

Pancreatic ductal adenocarcinoma is a highly aggressive disease with a grim prognosis. Surgical resection offers the best chance for long-term survival. Negative-margin resection still remains the goal, the influence of margin status on outcomes in pancreatic head carcinoma remains controversial, as conflicting data have been plagued by a lack of standardization in R0 resection and margin definitions, pathologic analysis, and reporting. In contrast to common belief, a high rate of R1 resections in pancreatic cancer is not a marker of low-quality surgery but rather of high-quality pathology. The international pathological consensus of pancreatic head carcinoma is still needed to fully understand the prognostic value of margin status in order to optimize treatment strategy for this disease.

Molecular characterization and upregulation of cytosolic manganese superoxide dismutase by imidazole derivative KK-42 in Macrobrachium nipponense

Imidazole derivative KK-42 is a well-known regulator of insect growth. KK-42 pretreatment has been shown to promote the survival of Macrobrachium nipponense infected with Aeromonas hydrophila, possibly via activation of superoxide dismutase (SOD). In this study, the cytMnSOD gene was cloned from the hepatopancreas of M. nipponense using the rapid amplification of cDNA ends technique. The full-length cDNA of cytMnSOD was 1233 bp long, and the open reading frame was 858 bp long, encoding a 286-aa protein with a 60-aa leader sequence. The calculated molecular mass of the translated cytMnSOD protein was 31.33 kDa, with an estimated isoelectric point of 5.62. cytMnSOD contained two N-glycosylation sites, four conserved amino acids responsible for binding manganese, and a manganese SOD domain (DVWEHAYY). Real-time RT-PCR analysis showed that cytMnSOD was expressed in all tissues examined with the highest expression observed in the hepatopancreas. Levels of the cytMnSOD transcript in the hepatopancreas were highest in stage C of the molting cycle. Real-time PCR analysis revealed that cytMnSOD expression increased significantly 3, 6, and 12 h after KK-42 treatment, with simultaneous increases in SOD activity from 6 to 12 h. Our results demonstrate that cytMnSOD expression and SOD activity may be induced by KK-42, which may represent one of the molecular mechanisms through which KK-42 promotes increased survival of prawns infected with A. hydrophila.

Development and significance of SCAR marker QG12-5 for Canarium album (Lour.) Raeusch by molecular cloning from improved RAPD amplification

Sequence-characterized amplified region (SCAR) is a valuable molecular marker for the genetic identification of any species. This marker is mainly derived from molecular cloning of random amplified polymorphic DNA (RAPD). We have previously reported the use of an improved RAPD technique for the genetic characterization of different samples of Canarium album (Lour.) Raeusch (C. album). In this study, DNA fragments were amplified using improved RAPD amplified from different samples of C. album. The amplified DNA fragment was excised, purified from an agarose gel and cloned into a pGM-T vector; subsequently, a positive clone, called QG12-5 was identified by PCR amplification and enzymatic digestion and sequenced by Sanger di-deoxy sequencing method. This clone was revealed consisting of 510 nucleotides of C. album. The SCAR marker QG12-5 was developed using specifically designed PCR primers and optimized PCR conditions. This SCAR marker expressed seven continuous "TATG" [(TATG)n] tandem repeats, which was found to characterize C. album. Subsequently, this novel SCAR marker was deposited in GenBank with accession No. KT359568. Therefore, we successfully developed a C. album-specific SCAR marker for the identification and authentication of different C. album species in this study.

New Molecular Ferroelectrics Accompanied by Ultrahigh Second-Harmonic Generation

Second-harmonic generation (SHG) is one of the outstanding properties for practical applications. However, the great majority of molecular ferroelectric materials have very low nonlinear optical coefficients, attenuating their attractive performance. Here we synthesized (4-amino-2-bromopyridinium)(4-amino-2-bromopyridine)tetrafluoroborate (1), whose second-order nonlinear optical coefficient reaches up to 2.56 pm V(-1), 2.67 times of that of KDP, and (4-amino-2-bromopyridinium)tetrafluoroborate (2), possessing a more incredible large second-order nonlinear optical coefficient as high as 10.24 pm V(-1), 10.67 times that of KDP. The compound 1 undergoes two reversible phase transitions at around T1 = 244.1 K and T2 = 154.6 K, caused by dramatic changes of the protonated cations and order-disorder of anions, which was disclosed by differential scanning calorimetry, heat capacity, dielectric anomalies, SHG, and single-crystal X-ray diffraction analysis. The pyroelectric measurements reveal that compound 1 is a Rochelle salt type ferroelectric, which has a large spontaneous polarization of about 3 μC/cm(2).

The growth mechanism and ferroelectric domains of diisopropylammonium bromide films synthesized via 12-crown-4 addition at room temperature

Diisopropylammonium bromide (DIPAB) has attracted great attention as a molecular ferroelectric with large spontaneous polarization and high Curie temperature. It is hard to grow the ferroelectric phase DIPAB because of the appearance of the non-ferroelectric phase DIPAB at room temperature. Here, a ferroelectric thin film of DIPAB was successfully fabricated on a Si substrate using a spin coating method from aqueous solution via 12-crown-4 addition at room temperature. The ferroelectric DIPAB film with a thickness of hundreds of nanometers is distributed discontinuously on the substrate in narrow strips. The direction of polarization is along the narrow strip. Piezoresponse force microscopy (PFM) shows that the ferroelectric films have two kinds of domain structures: noncharged antiparallel stripe domains and charged head-to-head (H-H)/tail-to-tail (T-T) type domains. 12-crown-4 has been proved to play important roles in forming the H-H/T-T type domains. The Chynoweth method shows that the DIPAB films synthesized in this way show a better pyroelectric effect than DIPAB crystals.

Screening of differentially-expressed genes in the muscles of rabbit breeds with expression profile chip

The molecular mechanism underlying muscle development in rabbits is not well-understood. In the current study, differentially-expressed genes were scanned using an expression profile chip in New Zealand white rabbits (introduced breed) and Fujian yellow rabbits (local breed), and some of the genes were tested using reverse transcription-polymerase chain reaction. The amplification results were consistent with the microarray data. Fourteen and 13 genes involved in muscle development were identified in the dorsal longissimus and leg muscles, respectively. Myh6, Myh7, Myh7b, Myo5b, Tnnc1, Tpm3, and Acta2 were scanned in the longissimus and leg muscles. Thus, these genes may be involved in muscle fiber formation and muscle development in rabbits. This study provides a theoretical basis for improving meat quality, as well as for the future development and utilization of local meat rabbit breeds.

Ultrafast reduction in exchange interaction by a laser pulse: alternative path to femtomagnetism

Since the beginning of femtomagnetism, it has been hotly debated how an ultrafast laser pulse can demagnetize a sample and switch its spins within a few hundred femtoseconds, but no consensus has been reached. In this paper, we propose that an ultrafast reduction in the exchange interaction by a femtosecond laser pulse is mainly responsible for demagnetization and spin switching. The key physics is that the dipole selection rule demands two distinctive electron configurations for the ground and excited states and consequently changes the exchange interaction. Although the exchange interaction change is almost instantaneous, its effect on the spin is delayed by the finite spin wave propagation. Consistent with the experimental observation, the delay becomes longer with a stronger exchange interaction pulse. In spin-frustrated systems, the effect of the exchange interaction change is even more dramatic, where the spin can be directly switched from one direction to the other. Therefore, our theory has the potential to explain the essence of major observations in rare-earth transition metal compounds for the last seven years. Our findings are likely to motivate further research in the quest of the origin of femtomagnetism.

Leucine-rich repeat-containing G-protein-coupled receptor 5 is associated with invasion, metastasis, and could be a potential therapeutic target in human gastric cancer

Background:

Leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5), which is identified as a novel intestinal stem cell marker, is overexpressed in various tumours. In this study, we explore Lgr5 expression in gastric carcinoma and analyse its role in invasion, metastasis, and prognosis in carcinoma.

Methods:

A combination of immunohistochemistry, western blotting, and quantitative reverse transcription–polymerase chain reaction were used to detect mRNA and protein expression levels of Lgr5 and matrix metalloproteinase 2 (MMP2). Small interfering RNA against Lgr5 was designed, synthesised, and transfected into AGS cells. The effects of Lgr5 siRNA on cell invasion were detected by transwell invasion chamber assay and wound healing assay.

Results:

Leucine-rich repeat-containing G-protein-coupled receptor 5 expression was significantly higher in gastric carcinomas than in normal mucosa. Leucine-rich repeat-containing G-protein-coupled receptor 5 expression positively correlated with the depth of invasion, lymph node metastasis, distance of metastasis, and MMP2 expression levels. Multivariate analysis showed that Lgr5 had an independent effect on survival, and that it positively correlated with MMP2. Leucine-rich repeat-containing G-protein-coupled receptor 5 siRNAs inhibited Lgr5 mRNA and protein expression. Transwell assays indicated that these siRNAs resulted in significantly fewer cells migrating through the polycarbonate membrane, and wound healing assay also indicated that siRNAs decreased the migration of cells. Inhibition of Lgr5 resulted in a significant decrease in MMP2 and β-catenin levels compared with those in controls.

Conclusions:

Leucine-rich repeat-containing G-protein-coupled receptor 5 was correlated with invasion and metastasis. Leucine-rich repeat-containing G-protein-coupled receptor 5 inhibition could serve as a novel therapeutic approach.

Magnetic ordering and structural phase transitions in a strained ultrathin SrRuO3/SrTiO3 superlattice

Ruthenium-based perovskite systems are attractive because their structural, electronic, and magnetic properties can be systematically engineered. The SrRuO3/SrTiO3 superlattice, with its period consisting of one unit cell each, is very sensitive to strain change. Our first-principles simulations reveal that, in the high tensile strain region, it transits from a ferromagnetic metal to an antiferromagnetic insulator with clear tilted octahedra, while in the low strain region, it is a ferromagnetic metal without octahedra tilting. Detailed analyses of three spin-down Ru-t(2g) orbitals just below the Fermi level reveal that the splitting of these orbitals underlies these dramatic phase transitions, with the rotational force constant of RuO(6) octahedron high up to 16 meV/Deg(2), 4 times larger than that of TiO(6). Differently from nearly all the previous studies, these transitions can be probed optically through the diagonal and off-diagonal dielectric tensor elements. For a 1% change in strain, our experimental spin moment change is -0.14±0.06 μ(B), quantitatively consistent with our theoretical value of -0.1 μ(B).

Multicavity x-ray Fabry-Perot resonance with ultrahigh resolution and contrast

Realization of x-ray Fabry-Perot (FP) resonance in back-Bragg-reflection crystal cavities has been proposed and explored for many years, but to date no satisfactory performance has been achieved. Here we show that single-cavity crystal resonators intrinsically have limited finesse and efficiency. To break this limit, we demonstrate that monolithic multicavity resonators with equal-width cavities and specific plate thickness ratios can generate ultrahigh-resolution FP resonance with high efficiency, steep peak tails, and ultrahigh contrast simultaneously. The resonance mechanism is similar to that of sequentially cascaded single-cavity resonators. The ultranarrow-bandwidth FP resonance is anticipated to have various applications, including modern ultrahigh-resolution or precision x-ray monochromatization, spectroscopy, coherence purification, coherent diffraction, phase contrast imaging, etc.

Efficiency of I-factors in offspring of isogenic lines of Drosophila melanogaster

In order to obtain information about mechanisms to control the strength of I-effects in Drosophila melanogaster, a genome from a spontaneously arising I-type line was introduced into an isogenic R-type w-K line with cytoplasm of strong R-reactivity. From the homozygous w-K offspring, five families, each with four sublines, were established by single pair-mating for five generations and then mass-mating. In a similar way, another 24 sub-lines were derived from six selected sublines in F9. The strength of the I-effect for the various sublines and sub-sublines was tested at the 8th, 17th, and 18th generations. The results indicated that there was great disparity between and within some families and the trends of family difference remained in successive generations. Such a result supports the hypothesis that the position effect is the main determinant of the I-effect.

Variation in the strength of R-reactivity and I-inductivity in inbred lines of Drosophila melanogaster

Two sets of two sister lines of Drosophila melanogaster, with common genome and cytoplasms of different origin, originally showed intermediate R-effects. All four lines had been kept at constant protocol for about 150 generations. From each of the four lines three sublines were established from single females and the strength of R-reactivity was tested by chromosomal loss technique. In two of the four sets, there was heterogeneity between the sublines. One subline in both cases was similar to the three sublines from the sister lines. The remaining two sets remained unchanged. Specific reactions were found in particular combinations of R- and I-lines. Six sets of independently arising I-lines with K-genome showed different response in the strength of their I-inductivity. The evolutionary relation in the strength of R-reactivity of R-type lines and the implication of the specific reactions are discussed.

Hysteretic behavior of angular dependence of exchange bias in FeNi/FeMn bilayers

For FeNi/FeMn bilayers, the angular dependence of exchange bias shows hysteresis between clockwise and counterclockwise rotations, as a new signature. The hysteresis decreases for thick antiferromagnet layers. Calculations have clearly shown that the orientation of antiferromagnet spins also exhibits hysteresis between clockwise and counterclockwise rotations. This furnishes an interpretation of the macroscopic behavior of the ferromagnetic layer in terms of the thermally driven evolution of the magnetic state of the antiferromagnet layer.

Spin proximity effect in ultrathin superconducting Be-Au bilayers

We present a detailed study of the effects of interface spin-orbit coupling on the critical field behavior of ultrathin superconducting Be/Au bilayers. Parallel field measurements were made in bilayers with Be thicknesses in the range of d=2-30 nm and Au coverages of 0.5 nm. Though the Au had little effect on the superconducting gap, it produced profound changes in the spin states of the system. In particular, the parallel critical field exceeded the Clogston limit by an order of magnitude in the thinnest films studied. In addition, the parallel critical field unexpectedly scaled as [FORMULA: SEE TEXT], suggesting that the spin-orbit coupling energy was proportional to Delta0/d2. Tilted field measurements showed that, contrary to recent theory, the interface spin-orbit coupling induces a large in-plane superconducting susceptibility but only a very small transverse susceptibility.

Orbital response of evanescent cooper pairs in paramagnetically limited Al films

We report a detailed study of the pairing resonance via tunneling density of states in ultrathin superconducting Al films in supercritical magnetic fields. Particular emphasis is placed on the effects of the perpendicular component of the magnetic field on the resonance energy and magnitude. Though the resonance is broadened and attenuated by H(perpendicular) as expected, its energy is shifted upward linearly with H(perpendicular). Extension of the original theory of the resonance to include strong perpendicular fields shows that at sufficiently large H(perpendicular) the overlap of the broadened resonance tail with the underlying degenerate Fermi sea alters the spectral distribution of the resonance via the exclusion principle. This leads to the shift of the resonance feature to higher energy.

Low-temperature susceptibility of the noncentrosymmetric superconductor CePt3Si

We report ac susceptibility measurements of polycrystalline CePt(3)Si down to 60 mK and in applied fields up to 9 T. In a zero applied field, a full Meissner state emerges at temperatures T/T(c) < 0.3, where T(c) = 0.65 K is the onset transition temperature. Though transport measurements show a relatively high upper critical field B(c2) approximately 4-5 T, the low-temperature susceptibility chi(') is quite fragile to the applied field, with chi(') diminishing rapidly in fields of a few kG. Interestingly, the field dependence of chi(') is well described by the power law 4pichi(') + 1 = (B/B(c))(1/2), where B(c) is the field at which the onset of resistance is observed in transport measurements.

Synthesis, characterization, biodegradation, and drug delivery application of biodegradable lactic/glycolic acid polymers. Part II: biodegradation

A series of previously-synthesized lactic/glycolic acid polymers (PLGA) with various molar ratios of lactic to glycolic acid and various molecular weights were further studied with regard to their biodegradation behavior, and in particular, the factors affecting the biodegradation rate. The biodegradation of PLGA is affected by many factors including polymer composition, molecular weight, and nature of the incubating media. The biodegradation rate of PLGA containing higher content of lactic acid moiety is lower than those containing a lower content of lactic acid moiety. PLGAs with a higher molecular weight, degrade faster than those with a lower molecular weight, i.e. the molecular weight decreases more rapidly for higher molecular weight PLGAs than their lower molecular weight counterparts. Nature or properties of the hydrolysis/incubating media may have an effect on the biodegradation of PLGAs. A basic medium may slow down the biodegradation of PLGA in comparison with samples in an acidic medium. The rate of pH reduction for the incubating medium can be divided into three deferent phases, giving an inverted S-type pH profile for the non-buffered incubating media.

Prospects of chimeric RNA-DNA oligonucleotides in gene therapy

A strategy called targeted gene repair was developed to facilitate the process of gene therapy using a chimeric RNA-DNA oligonucleotide. Experiments demonstrated the feasibility of using the chimeric oligonucleotide to introduce point conversion in genes in vitro and in vivo. However, barriers exist in the low and/or inconstant frequency of gene repair. To overcome this difficulty, three main aspects should be considered. One is designing a more effective structure of the oligonucleotide. Trials have included lengthening the homologous region, displacing the mismatch on the chimeric strand and inventing a novel thioate-modified single-stranded DNA, which was demonstrated to be more active than the primary chimera in cell-free extracts. The second aspect is optimizing the delivery system. Producing synthetic carriers for efficient and specific transfection is demanding, especially for treatment in vivo where targeting is difficult. The third and most important aspect lies in the elucidation of the mechanism of the strategy. Investigation of the mechanism of strand exchange between the oligonucleotide molecule and double-stranded DNA in prokaryotes may greatly help to understand the mechanism of gene repair in eukaryotes. The development of this strategy holds great potential for the treatment of genetic defects and other purposes.

Protein kinase c increases the apparent affinity of the release machinery to Ca2+ by enhancing the release machinery downstream of the Ca2+ sensor

Modulation of the release probability of releasable vesicles in response to Ca(2+) influx (Prob(Ca)) is involved in mediating several forms of synaptic plasticity, including short-term depression, short-term augmentation, and potentiation induced by protein kinases. Given such an important role, however, the mechanism underlying modulation of the Prob(Ca) is unclear. We addressed this question by investigating how the activation of protein kinase C modulates the Prob(Ca) at a calyx-type nerve terminal in rat brainstem. Various lengths of step depolarization were applied to the nerve terminal to evoke different amounts of Ca(2+) currents and capacitance jumps, the latter of which reflect vesicle release. The relationship between the capacitance jump and the Ca(2+) current integral was sigmoidal and was fit well with a Hill function. The sigmoidal relationship was shifted significantly to the left during the application of the PKC activator 12-myristate 13-acetate (PMA), suggesting that PMA increases the apparent affinity of the release machinery to Ca(2+). This effect was blocked in large part by the application of the PKC inhibitor bisindolylmaleimide, suggesting that the effect is mediated mainly by the activation of PKC. We also found that PMA increased the rate of miniature EPSCs evoked by the application of hypertonic sucrose solution, which triggers release downstream of the Ca(2+) influx. Taken together, our results suggest that PKC enhances the apparent affinity of the release machinery to Ca(2+) by a mechanism downstream of the binding between Ca(2+) and its sensor. These results have provided the first example of the mechanisms underlying modulation of the Prob(Ca).

[Mutations of genes affecting heart development of Drosophila]

Recent studies suggest that the basic molecular control mechanisms of early heart development are remarkably conserved in Drosophila, vertebrate and human being. Drosophila can be used as a prototype to explore the genetic basis of cardiogenesis in human being. Here, mutations of genes affecting heart development of Drosophila are produced by chemical mutagen methanesulfonicaeid ethyl. With staining of antibody expressed in heart precussor cells of Drosophila, 112 lethal lines were observed to show mutant phenotypes in pericardial cells. Of them, 32 lines differ in their mutant phenotypes from those of known genes. Analysis of cytogenetic mapping shows that they are located in 13 chromosomal regions without known heart-related genes, which implies that these loci contain genes probably involved in the heart development.

Synthesis, characterization, biodegradation, and drug delivery application of biodegradable lactic/glycolic acid polymers: I. Synthesis and characterization

A series of lactic/glycolic acid polymers with various molar ratios of lactic to glycolic acid and various molecular weights were synthesized using the ring-opening polymerization method. The polymerization conditions for the lactic/glycolic acid polymer synthesis were as follows: 150 degrees C, 700 microm Hg, 3 h, 0.03 wt% of catalyst (stannous 2-ethyl-hexanoate) concentration. The molecular weight of these polymers was controlled by using a molecular weight controller, lauryl alcohol. The synthesized polymers have been characterized with respect to polymer composition, molecular weight, inherent viscosity, and glass transition temperature. The characterization experiments show a good correlation between the polymer compositions and the feed ratios of lactic to glycolic acid. The molecular weight of the lactic/glycolic polymers, ranging from 10,876 to 166,630 D and the intrinsic viscosity of the polymers, ranging from 0.16 to 0.86 dl g(-1), are controlled by the amount of molecular weight controller used. The effect of the amount of the molecular weight controller on the polymer molecular weight and the polymer inherent viscosity was studied. Results indicate that the molecular weight and inherent viscosity of the polymers have a log-log linear relationship with the amount of molecular weight controller used. The lactic/glycolic acid polymers are amorphous, glassy, and transparent. The glass transition temperature of the polymers range from 21.95 to 51.29 degrees C, depending on the polymer molecular weight and the composition.

Side chain orientation in the selectivity filter of a voltage-gated Ca2+ channel

Four glutamate residues (EEEE locus) are essential for ion selectivity in voltage-gated Ca(2+) channels, with ion-specific differences in binding to the locus providing the basis of selectivity. Whether side chain carboxylates or alternatively main chain carbonyls of these glutamates project into the pore to form the ion-binding locus has been uncertain. We have addressed this question by examining effects of sulfhydryl-modifying agents (methanethiosulfonates) on 20 cysteine-substituted mutant forms of an L-type Ca(2+) channel. Sulfhydryl modifiers partially blocked whole oocyte Ba(2+) currents carried by wild type channels, but this block was largely reversed with washout. In contrast, each of the four EEEE locus glutamate --> cysteine mutants (0 position) was persistently blocked by sulfhydryl modifiers, indicating covalent attachment of a modifying group to the side chain of the substituted cysteine. Cysteine substitutions at positions immediately adjacent to the EEEE locus glutamates (+/-1 positions) were also generally susceptible to sulfhydryl modification. Sulfhydryl modifiers had lesser effects on channels substituted one position further from the EEEE locus (+/-2 positions). These results indicate that the carboxylate-bearing side chains of the EEEE locus glutamates and their immediate neighbors project into the water-filled lumen of the pore to form an ion-binding locus. Thus the structure of the Ca(2+) channel selectivity filter differs substantially from that of ancestral K(+) channels.