Deep learning radiomic nomogram can predict the number of lymph node metastasis in locally advanced gastric cancer: an international multicenter study.

BACKGROUND: Preoperative evaluation of the number of lymph node metastasis (LNM) is the basis of individual treatment of locally advanced gastric cancer (LAGC). However, the routinely used preoperative determination method is not accurate enough. PATIENTS AND METHODS: We enrolled 730 LAGC patients from five centers in China and one center in Italy, and divided them into one primary cohort, three external validation cohorts, and one international validation cohort. A deep learning radiomic nomogram (DLRN) was built based on the images from multiphase computed tomography (CT) for preoperatively determining the number of LNM in LAGC. We comprehensively tested the DLRN and compared it with three state-of-the-art methods. Moreover, we investigated the value of the DLRN in survival analysis. RESULTS: The DLRN showed good discrimination of the number of LNM on all cohorts [overall C-indexes (95% confidence interval): 0.821 (0.785-0.858) in the primary cohort, 0.797 (0.771-0.823) in the external validation cohorts, and 0.822 (0.756-0.887) in the international validation cohort]. The nomogram performed significantly better than the routinely used clinical N stages, tumor size, and clinical model (P < 0.05). Besides, DLRN was significantly associated with the overall survival of LAGC patients (n = 271). CONCLUSION: A deep learning-based radiomic nomogram had good predictive value for LNM in LAGC. In staging-oriented treatment of gastric cancer, this preoperative nomogram could provide baseline information for individual treatment of LAGC.

Puerarin alleviates the progression of non-small cell lung cancer by regulating the miR-342/CCND1 axis.

Puerarin has recently been demonstrated to play anti-cancer roles in a series of human cancers, including non-small cell lung cancer (NSCLC), possibly through regulation of cancer-related microRNAs (miRNAs). The purpose of the present study was to further investigate the detailed role and underlying mechanism of puerarin on NSCLC progression. Cell viability and apoptosis were assessed using the Cell Counting kit-8 (CCK-8) assay and flow cytometry, respectively. Transwell assays were performed to determine cell migration and invasion abilities. The qRT-PCR assay was employed to detect the expression of miR-342 and cyclin D1 (CCND1) mRNA, and CCND1 protein expression was evaluated by western blotting. The targeted interaction between miR-342 and CCND1 was verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. We found that our data demonstrated that puerarin repressed cell viability, migration, invasion, and cell cycle progression, and enhanced the apoptosis of NSCLC cells. miR-342 overexpression hindered the migration, invasion and cell cycle progression, and accelerated the apoptosis of NSCLC cells. miR-342 inhibited CCND1 expression by directly binding to the 3'-UTR of CCND1. Moreover, miR-342 overexpression-mediated anti-migration, anti-invasion, anti-cell cycle progression, and pro-apoptotic effects were abated by co-transfection of pcDNA-CCND1. More importantly, puerarin inhibited CCND1 expression by upregulating miR-342. Additionally, puerarin hampered NSCLC cell progression in vitro and tumor growth in vivo by upregulating miR-342. In conclusion, our study suggested that puerarin hampered NSCLC progression in vitro and in vivo at least partly through regulating miR-342/CCND1 axis, highlighting a novel mechanism of puerarin exerting anti-cancer property in NSCLC.

[mRNA genomics change and significance of important ion channel proteins in patients with atrial fibrillation].

Objective: To investigate the mRNA genomics changes and significance of important ion channel proteins in patients with atrial fibrillation (AF), to reveal the mechanism of electrical remodeling in AF. Methods: Ninety patients with AF were chosen to receive the radiofrequency ablation (AF-RFA), 90 healthy subjects were included as the normal control group.The coronary sinus blood and peripheral venous blood were taken from each AF patient during the operation of AF-RFA.The genome-wide mRNA expression profile was analyzed with mRNA microarray chip, and the mRNA expression difference results for the major ion channel gene was further validated using Real-time PCR test. Results: The expression of twelve ion channel protein mRNA increased ≥2.0-fold, expression of 10 mRNA decreased ≥2.0-fold, among which K(+) channel gene KCNE4, KCND2, KCNN4 declined obviously, KCNA5 dropped 11.54-fold (P< 0.01); KCNS3, KCNS1, KCNG1, KCNG7 and Ca(+ +) channel gene CACNA2D3 increased significantly.Compared with autologous peripheral blood, 12 mRNAs of ion channel protein in coronary sinus blood of AF patients was differentially expressed ≥2.0-fold.Compared with control group in peripheral blood, 7 ion channel protein mRNA expression differences was ≥2.0-fold, and the KCNA5 gene expression was down by 8.13-fold.RT-PCR confirmed that the trend and extent of differential expression were consistent with the chip results.The results of myocardial tissue RT-PCR showed that CACNA1C, KCNC3, KCNG1 and KCNK7 mRNA were up-regulated in AF (P<0.05), and other ion channel mRNA expressions were down-regulated (P<0.05). KCNA5 was down-regulated most obvious. Conclusion: The down-regulation of KCNA5 gene expression in AF patients is most obvious, and more potassium ion channel expression differences are also significant, so that the potassium ion channel reconstruction may play a dominant or much more important role in AF electrical remodeling.

Coulomb Correlations Intertwined with Spin and Orbital Excitations in LaCoO_{3}.

We carried out temperature-dependent (20-550 K) measurements of resonant inelastic x-ray scattering on LaCoO_{3} to investigate the evolution of its electronic structure across the spin-state crossover. In combination with charge-transfer multiplet calculations, we accurately quantified the renomalized crystal-field excitation energies and spin-state populations. We show that the screening of the effective on-site Coulomb interaction of 3d electrons is orbital selective and coupled to the spin-state crossover in LaCoO_{3}. The results establish that the gradual spin-state crossover is associated with a relative change of Coulomb energy versus bandwidth, leading to a Mott-type insulator-to-metal transition.

[Value of two left atrium and pulmonary vein stereoscopic imaging reconstruction methods on guiding radiofrequency ablation for atrial fibrillation].

Objective: To compare the value of two 3D imaging reconstruction methods for left atria and pulmonary vein on guiding the catheter ablation for atrial fibrillation (AF). Methods: From January 2014 to January 2017, a total of 100 drug refractory paroxysmal AF patients were divided into left atria direct angiography group (n=50), and indirect angiography group (n=50). 3D CARTO system was applied for mapping and guiding the ablation procedure. Patients assigned to direct angiography group were treated as follows: intraoperative puncture of atrial septum, inject contrast agent directly into the left atrium, conduct left atrial and pulmonary venous rotation angiography, reconstruct three-dimensional image, integrate the image into real-time X-ray system to facilitate circumferential pulmonary vein isolation. Patients assigned into the indirect angiography group were treated as follows: inject contrast agent through the right ventricle, conduct delayed rotation angiography of the left atria and pulmonary vein to guide circumferential pulmonary vein fixation and ablation. The left atrial and pulmonary venous image acquisition, the operation and X-ray exposure time, the success rate and the incidence of complication of the two groups were compared. The patients were followed up for 3-6 months. Results: General clinical characteristics of the two groups were similar(all P>0.05). Ablation was successful in all 100 patients. The operation time[(112.0±21.4)min vs. (134.0±24.3)min]and X-ray exposure time((10.7±4.7)min vs. (15.8±5.2)min)were significantly lower in direct angiography group than in indirect angiography group (both P<0.01). There was no significant difference between the two groups in the immediate (86%(43/50) vs. 82%(41/50), P=0.59) and short-term (76%(38/50) vs. 72%(36/50), P=0.65) success rate and complication rate (1 aneurysm in the direct angiography group, 1 pericardial tamponade in the indirect angiography group). In-hospital mortality was zero percent. Conclusion: It is safe and effective method to guide the radiofrequency catheter ablation of paroxysmal atrial fibrillation by reconstruction 3D image of left atrium and pulmonary vein. Compared with indirect angiography group, direct angiography group can improve the imaging quality of left atrium and pulmonary vein, decrease the X-ray exposure time of the ablation procedure.

[Evaluation of the relationship between the attachment type of lateral pterygoid muscle and the position of temporomandibular joint disc in patients with temporomandibular joint disorders based on wireless amplified MRI detector high resolution imaging].

Objective: To explore the correlation between the attachment type of lateral pterygoid muscle (LPM) and the position of temporomandibular joint (TMJ) disc in patients with temporomandibular disorders (TMD) by using wireless amplified magnetic resonance imaging detector (WAND) coupled with conventional head and neck joint coil for high resolution imaging of TMJ. Methods: Eighty-five patients with TMD diagnosed by oral and maxillofacial surgeons of Guizhou Provincial People's Hospital from October 2019 to January 2022 were collected. A total of 160 TMJ were included. There were 16 males and 69 females, aged (32.7±14.2) years. All patients were scanned with open, closed oblique sagittal and coronal WAND coupled head and neck coils with bilateral TMJ. Based on TMJ and LPM high resolution imaging, to explore the correlation between LPM attachment types and the position of TMJ disc in TMD patients, and to evaluate the potential clinical value of LPM attachment types in TMD patients. χ2 test and Pearson correlation analysis were used to evaluate the correlation between LPM attachment type and TMJ disc location. Results: There were three types of LPM attachment: type Ⅰ in 51 cases [31.9% (51/160)], type Ⅱ in 77 cases [48.1% (77/160)] and type Ⅲ in 32 cases [20.0% (32/160)]. There was a significant correlation between the type of LPM attachment and the position of articular disc (χ2=28.20, P=0.002, r=0.776). There was no statistical significance between the type of LPM attachment and the reversible displacement of articular disc (χ2=0.24, P=0.887, r=0.825). Conclusions: There is a correlation between the attachment type of LPM and the position of the disc in TMD patients. WNAD coupled with conventional head and neck joint coil TMJ high resolution scan can provide reliable imaging evidence for TMD patients in evaluating the type of LPM attachment and the location of disc.

Near-zero anomalous dispersion Ge11.5As24Se64.5 glass nanowires for correlated photon pair generation: design and analysis.

We show that highly nonlinear chalcogenide glass nanowire waveguides with near-zero anomalous dispersion should be capable of generating correlated photon-pairs by spontaneous four-wave mixing at frequencies detuned by over 17 THz from the pump where Raman noise is absent. In this region we predict a photon pair correlation of >100, a figure of merit >10 and brightness of ~8×10(8) pairs/s over a bandwidth of >15 THz in nanowires with group velocity dispersion of <5 ps∙km(-1) nm(-1). We present designs for double-clad Ge(11.5)As(24)Se(64.5) glass nanowires with realistic tolerance to fabrication errors that achieve near-zero anomalous dispersion at a 1420 nm pump wavelength. This structure has a fabrication tolerance of 80-170 nm in the waveguide width and utilizes a SiO(2)/Al(2)O(3) layer deposited by atomic layer deposition to compensate the fabrication errors in the film thickness.

Clinical application of cinematic rendering in maxillofacial fractures.

The purpose of this study was to evaluate the clinical application of cinematically rendered reconstructions of maxillofacial fractures. Ten surgeons and eight radiologists were shown three-dimensional images of 25 different patient cases, generated using both the volume rendering (VR) technique and the cinematic rendering (CR) technique. They were asked to mark the site of the fracture on the three-dimensional images and record the time this activity took. The effectiveness of the reconstructions to communicate with patients was assessed through the opinions of the surgeons and radiologists, as well as 25 patients. Subjective evaluations of the clinical value of the images were performed by the 18 surgeons and radiologists using a 10-item questionnaire. The percentages of correctly identified fractures of the nasal bone (P = 0.034), fracture dislocation (P < 0.001), and free bone fragments (P < 0.001) were significantly higher for CR images when compared to VR images, and identification took an average of 20.81 seconds for CR and 27.48 seconds for VR (P < 0.001). CR images were found to be more beneficial for communication with patients and scored higher for the display of fracture dislocation and free bone fragments than VR images (P < 0.05). CR images were found to have high clinical value in the visualization of maxillofacial fractures.

Efficacy and safety of a levonorgestrel enteric-coated tablet as an over-the-counter drug for emergency contraception: a Phase IV clinical trial.

BACKGROUND: An enteric-coated levonorgestrel emergency contraceptive pill (E-LNG-ECP) is an improved formulation, in terms of side effects, which both dissolves and is absorbed in the intestine. Our aim was to evaluate the efficacy and safety of E-LNG-ECP as an over-the-counter (OTC) drug for emergency contraception (EC) in Chinese women. METHODS: A Phase IV clinical trial was conducted in five family planning clinics in China. Women seeking EC within 72 h after unprotected sexual intercourse or contraceptive failure who met the inclusion criteria were recruited. The efficacy of contraception (primary end-point was pregnancy rate), side effects (i.e. safety) and the value of E-LNG-ECP for EC were investigated. RESULTS: Of 2445 women (aged 15-48 years) who took E-LNG-ECP with follow-up to determine pregnancy, only five pregnancies (0.2%) occurred. The efficacy of contraception was 95.3%. In total, 6.5% of women reported at least one adverse event after taking E-LNG-ECP, and no serious adverse events were reported. Only four subjects (0.16%) reported vomiting. The incidence of menstrual cycle disturbance was 20.1% after taking E-LNG-ECP. Subjects who had previously taken ECPs (54.4% of these women) rated the acceptability of E-LNG-ECP at 9.36 (on a 10-point scale) higher (P<0.05) than the rating of other LNG-EC pills taken previously. CONCLUSIONS: The study found that E-LNG-ECP was effective, safe and well tolerated as an OTC drug. However, an randomized controlled trial should be performed to compare standard LNG tablets with E-LNG-ECP.

Changes in serum inflammatory factors, adiponectin, intestinal flora and immunity in patients with non-small cell lung cancer.

OBJECTIVE: The aim of this study was to explore the changes in the body state of patients with non-small cell lung cancer (NSCLC), including intestinal flora, serum inflammatory factors, immunity and adiponectin. PATIENTS AND METHODS: A total of 18 NSCLC patients (disease group) and 16 healthy people from the Medical Center (control group) were selected as research objects. The levels of immune molecules immunoglobulin A (IgA), IgG and IgM, and inflammatory factors interleukin-2 (IL-2), C-reactive protein (CRP), tumor necrosis factor-α (TNF-α) and IL-6 were detected via enzyme-linked immunosorbent assay (ELISA). The level of adiponectin was determined using the quantitative kit. In addition, the changes in intestinal flora were analyzed. RESULTS: The overall survival time of NSCLC patients was significantly affected by IL-2 (p=0.0026), CRP (p=0.03), TNF-α (p=0.014) and IL-6 (p=0.00018). It can be seen that these inflammatory factors may play important roles in the progression of NSCLC. The levels of TNF-α (p=0.037), IL-2 (p=0.043) and CRP (p=0.000) in the peripheral blood serum were significantly higher in disease group than control group. Meanwhile, the levels of IgA (p=0.040) and IgG (p=0.000) in the peripheral blood serum were significantly higher in disease group than control group. However, no significant difference was observed in the level of IgM between the two groups (p>0.05). The expression of adiponectin gene (ADIPOQ) could remarkably affect the overall survival rate of NSCLC patients, and patients with high expression of ADIPOQ exerted significantly better prognosis (p=0.017). The level of serum adiponectin was evidently higher in control group than that in disease group (p<0.05). According to the linear discriminant analysis (LDA) score of the intestinal flora in both groups, the abundance of some intestinal flora (Enterobacter and Lachnospiraceae) was markedly higher in disease group than control group (p<0.05). However, the abundance of Bifidobacteria, Pediococcus and Lactobacillus was remarkably higher in control group than disease group (p<0.05). Correlation analysis indicated that Lactobacillus was positively correlated with Bifidobacteria (r=0.44, p=0.000), whereas was negatively correlated with Enterobacter (r=-0.22, p=0.024). Furthermore, Enterobacter was negatively associated with Bifidobacteria (r=-0.15, p=0.038) and Streptococcus (r=-0.12, p=0.046). CONCLUSIONS: Serum inflammatory factors, adiponectin, intestinal flora and immunity may play important roles in the development of NSCLC.

Increased long noncoding RNA LINC00511 is correlated with poor prognosis and contributes to cell proliferation and metastasis by modulating miR-424 in hepatocellular carcinoma.

OBJECTIVE: Long noncoding RNAs (lncRNAs) have been reported to be abnormally expressed in human hepatocellular carcinoma (HCC) and associated with the progression of HCC. LncRNA LINC00511 (LINC00511) has been confirmed to act as a tumor promoter in several tumors. However, as a novel lncRNA, the specific effect of LINC00511 is still largely obscure. In this study, we aimed to evaluate the effect of LINC00511 in HCC behaviors and to elucidate the mechanism by which this occurs. PATIENTS AND METHODS: The expressions of LINC00511 in HCC tissues and cell lines were evaluated by qRT-PCR. The correlations between LINC00511 expression and the clinicopathological parameters and prognosis of HCC patients were determined using several statistical methods. CCK-8 assay, colony formation assay, flow cytometry cell cycle, apoptosis assay, EdU assay, wound healing assay, and transwell assay were used to investigate the role of LINC00511 on the malignant phenotypes in vitro. Insights into the potential mechanisms of ceRNAs were determined by bioinformatics analysis, dual-luciferase reporter assays and RT-PCR. RESULTS: LINC00511 expression was significantly up-regulated in HCC tissues and cell lines, and its high expression was distinctly associated with nodal metastasis, vascular invasion, and clinical stage. Furthermore, statistical assays revealed that HCC patients with higher LINC00511 expression levels had worse overall survival rates. Importantly, the multivariate analysis confirmed that LINC00511 expression was an independent prognostic factor of the overall survival in patients with HCC. Functionally, the inhibition of LINC00511 significantly suppressed the capability of proliferation, migration, and invasion in HCC cell lines. Bioinformatic tools predicted that miR-424 both targeted the 3'-UTR of LINC00511, which was confirmed using the luciferase reporter assay and RT-PCR. CONCLUSIONS: LINC00511 plays an important role in the malignant progression of HCC via modulation of miR-424.

[Epidemiological features of adult chronic kidney diseases in a community-based population in Songjiang district, Shanghai].

Objective: To investigate the prevalence and associated factors of chronic kidney diseases (CKD) in adult residents living in a community of Songjiang district, Shanghai. Methods: A total of 9 257 residents aged 20-75 years old in Xinqiao township of Songjiang district were selected by random cluster sampling. All the participants were interviewed to complete a set of personal questionnaire and undergo physical examinations. Urine and blood tests including markers of kidney damage and related associated factors with CKD, were carried out. Results: Eligible data from 8 207 subjects were enrolled in the study. After adjustment for age and gender, the prevalence of CKD was 8.4% (95%CI: 7.8%-9.0%), with majority of the patients (76.5%) appeared in the early stage (Ⅰ and Ⅱ) of the disease. The prevalence of CKD increased with age and higher prevalence was seen in females than in males (P<0.001). Results from logistic regression analysis showed that factors as: being elderly or female, having hypertension, hyperuricemia, and hyperlipidemia were all independently associated with CKD. Conclusions: The prevalence of CKD appeared relatively high in adult residents of Xinqiao township, Songjiang district where CKD had become a public health problem. Factors as: being female or elderly, hypertension, hyperuricemia, and hyperlipidemia were found to be associated with CKD. Our findings suggested that early prevention and control on CKD to reduce the incidence of end-stage renal diseases and related complications had called for more urgent attention.

Anesthetic management for cesarean delivery in a patient with uncorrected pulmonary atresia, ventricular septal defect and major aortopulmonary collateral arteries.

Pulmonary atresia witha ventricular septal defect and major aortopulmonary collateral arteries is an extremely rare congenital disorder characterized by a high risk of maternal mortality. We present the case of a 24-year-old primigravid woman with uncorrected pulmonary atresia, ventricular septal defect and major aortopulmonary collateral arterieswho presented at 35+5 weeks' gestation. Based on the pathophysiology of the congenital cardiac lesion, cesarean delivery was performed under epidural anesthesia under management by a multidisciplinary team. This report highlights the anesthesia management of a rare uncorrected congenital cardiac lesion for cesarean delivery.

Molecular cloning and expression of human cDNAs encoding a novel DNA ligase IV and DNA ligase III, an enzyme active in DNA repair and recombination.

Three distinct DNA ligases, I to III, have been found previously in mammalian cells, but a cloned cDNA has been identified only for DNA ligase I, an essential enzyme active in DNA replication. A short peptide sequence conserved close to the C terminus of all known eukaryotic DNA ligases was used to search for additional homologous sequences in human cDNA libraries. Two different incomplete cDNA clones that showed partial homology to the conserved peptide were identified. Full-length cDNAs were obtained and expressed by in vitro transcription and translation. The 103-kDa product of one cDNA clone formed a characteristic complex with the XRCC1 DNA repair protein and was identical with the previously described DNA ligase III. DNA ligase III appears closely related to the smaller DNA ligase II. The 96-kDa in vitro translation product of the second cDNA clone was also shown to be an ATP-dependent DNA ligase. A fourth DNA ligase (DNA ligase IV) has been purified from human cells and shown to be identical to the 96-kDa DNA ligase by unique agreement between mass spectrometry data on tryptic peptides from the purified enzyme and the predicted open reading frame of the cloned cDNA. The amino acid sequences of DNA ligases III and IV share a related active-site motif and several short regions of homology with DNA ligase I, other DNA ligases, and RNA capping enzymes. DNA ligases III and IV are encoded by distinct genes located on human chromosomes 17q11.2-12 and 13q33-34, respectively.

Jahn-Teller distortion driven magnetic polarons in magnetite.

The first known magnetic mineral, magnetite, has unusual properties, which have fascinated mankind for centuries; it undergoes the Verwey transition around 120 K with an abrupt change in structure and electrical conductivity. The mechanism of the Verwey transition, however, remains contentious. Here we use resonant inelastic X-ray scattering over a wide temperature range across the Verwey transition to identify and separate out the magnetic excitations derived from nominal Fe2+ and Fe3+ states. Comparison of the experimental results with crystal-field multiplet calculations shows that the spin-orbital dd excitons of the Fe2+ sites arise from a tetragonal Jahn-Teller active polaronic distortion of the Fe2+O6 octahedra. These low-energy excitations, which get weakened for temperatures above 350 K but persist at least up to 550 K, are distinct from optical excitations and are best explained as magnetic polarons.

Atrial natriuretic peptide inhibits sympathetic outflow in NaCl-sensitive spontaneously hypertensive rats.

The current study tested the hypothesis that circulating atrial natriuretic peptide (ANP) inhibits sympathetic outflow, as reflected in lumbar sympathetic nerve activity (LSNA), in NaCl-sensitive spontaneously hypertensive rats (SHR-S) and that this effect is exaggerated by high NaCl feeding. NaCl-resistant SHR (SHR-R) and Wistar-Kyoto (WKY) rats maintained on basal and high-NaCl diets were used as controls. Intravenous administration of ANP to conscious, freely moving rats with intact baroreflexes decreased blood pressure and LSNA in SHR-S, SHR-R and WKY rats maintained on basal or high-NaCl diets for 2-3 weeks. The depressor response to intravenous ANP was greater in 8% NaCl-fed SHR-S than in any other group; the LSNA response was greater in SHR-S on either diet than in any other group. Intracerebroventricular administration of ANP evoked small, transient sympatholytic responses in SHR-S on both diets and minimal responses in SHR-R and WKY rats; these responses could not be attributed to leakage of ANP into the peripheral circulation. Thus, circulating ANP has a sympatholytic effect in SHR-S that is not amplified by high-NaCl feeding and can be only partially accounted for by a central action.

[Interaction between pelvic and pudendal afferent inputs in lumbar-sacral spinal cord in rats].

Time-dependent inhibition is one of the means to study the interactions between peripheral inputs. The present study was performed on anesthetized and paralyzed Wistar rats using the technique of conditioning-testing stimulation. Electric stimulation (1.5 3 folds of the threshold intensity) was given to pelvic and pudendal nerves. Extracellular recordings were made from convergent neurons at L(6)-S(1) segments of the spinal dorsal horn. Stimulus intervals between conditioning and testing stimulation were measured when a half of the testing responses were inhibited by conditioning responses or the inhibition just began to occur. The time-dependent inhibition was seen in neurons situated deeper than 300 m beneath the dorsal surface of the spinal cord, and not in more superficial neurons. The inhibition intervals were in the range of 1 360 ms and became longer when conditioning stimulation was given to the pelvic nerve. The inhibition intervals were 1 3 ms in superficial neurons (<300 micrometer) and no apparent time-dependent inhibition occurred. The inhibition in deeper neurons was partially reduced by cold block conducted at segments C(5-6) and the blockage was more significant when conditioning stimulation was applied to the pelvic nerve. These findings suggest that the inputs from the pelvic and pudendal nerves may converge on single neurons at deeper lumbosacral dorsal horn and the pudendal nerve induced responses are more likely to be inhibited in these neurons, which may be further strengthened by superspinal structures.

[Effect of sodium nitroprusside on the spontaneous and induced responses of rat spinal cord dorsal horn neurons].

The present study was performed on anesthetized and paralyzed Wistar rats. Extracellular recordings were made from the lumbar enlargement of the spinal cord using carbon filament electrodes. NO donor sodium nitroprusside (SNP) was locally microdialyzed to the spinal cord, and effects of NO on spontaneous response and the responses induced by mechanical stimulation of the hind-foot were observed. After dialyzing for 10~20 min, SNP at a concentration of 1 micromol/L increased the induced responses to innocuous mechanical stimulation and decreased those to noxoius mechanical stimulation. The induced responses to both innocuous and noxious mechanical stimulations were all decreased after dialyzing the same dose of SNP for 20~30 min. The decrease was shown within 7~15 min dialysis when SNP was used at a concentration of 20 micromol/L. SNP at both concentrations of 1 and 20 micromol/L increased spontaneous spikes of the recorded spinal units. These effects were shown preferentially in deep units. The data suggest that in the deeper neurons of the spinal cord NO of different concentrations has different effects on transmission of nociceptive and nonnociceptive signals induced by mechanical stimulation, and No is involved in the antinociception in spinal neurons and facilitates their spontaneous activity.

Optical waves in a gradient negative-index lens of a half-infinite length.

Materials with negative permittivity and permeability can overcome the diffraction limit, thereby making the sub-wavelength imaging possible. In this study, we analyze the effects of gradient index on a half-infinite perfect lens. We assume that the sharp interface between the vacuum and the negative-index material is replaced by a smooth transition profile such that the index gradually changing from positive to negative. Interestingly, we find that if the graded index profile is modeled by a tanh function, we can have closed-form analytical solutions for this problem, which is a distinct advantage as numerical solutions are not accurate for evanescent waves with large transverse wave vectors. By analyzing the analytical formulas we confirm that a nonzero total absorption can occur even for a near-zero absorption coefficient in the steady-state limit and the image plane contains multiple sub-wavelength images of an object.

Structural investigations of Ge5As(x)Se(95-x) and Ge15As(x)Se(85-x) glasses using x-ray diffraction and extended x-ray fine structure spectroscopy.

The structure of Ge(5)As(x)Se(95-x) (x = 10, 20, 30, 38 at.%) and Ge(15)As(x)Se(85-x) (x = 10, 25, 34 at.%) glasses has been investigated by high-energy x-ray diffraction and extended x-ray absorption fine structure measurements. The experimental datasets have been modelled using the reverse Monte Carlo simulation technique. The model atomic configurations have been analysed in detail. It has been found that the homonuclear Ge-Ge, As-As, Se-Se and heteronuclear Ge-As bonds play an important role in the structure formation of the Ge-As-Se glasses. The total number of these bonds decreases quite slowly with the mean coordination number similarly to the nonlinear refractive index.