A segmentation model to detect cevical lesions based on machine learning of colposcopic images

Background

Semantic segmentation is crucial in medical image diagnosis. Traditional deep convolutional neural networks excel in image classification and object detection but fall short in segmentation tasks. Enhancing the accuracy and efficiency of detecting high-level cervical lesions and invasive cancer poses a primary challenge in segmentation model development.

Methods

Between 2018 and 2022, we retrospectively studied a total of 777 patients, comprising 339 patients with high-level cervical lesions and 313 patients with microinvasive or invasive cervical cancer. Overall, 1554 colposcopic images were put into the DeepLabv3+ model for learning. Accuracy, Precision, Specificity, and mIoU were employed to evaluate the performance of the model in the prediction of cervical high-level lesions and cancer.

Results

Experiments showed that our segmentation model had better diagnosis efficiency than colposcopic experts and other artificial intelligence models, and reached Accuracy of 93.29 %, Precision of 87.2 %, Specificity of 90.1 %, and mIoU of 80.27 %, respectively.

Conclution

The DeepLabv3+ model had good performance in the segmentation of cervical lesions in colposcopic post-acetic-acid images and can better assist colposcopists in improving the diagnosis.

A tera-electron volt afterglow from a narrow jet in an extremely bright gamma-ray burst

Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory of the bright GRB 221009A, which serendipitously occurred within the instrument field of view. More than 64,000 photons >0.2 TeV were detected within the first 3000 seconds. The TeV flux began several minutes after the GRB trigger, then rose to a peak about 10 seconds later. This was followed by a decay phase, which became more rapid ~650 seconds after the peak. We interpret the emission using a model of a relativistic jet with half-opening angle ~0.8°. This is consistent with the core of a structured jet and could explain the high isotropic energy of this GRB.

[Burned-out testicular germ cell tumors: a clinicopathological analysis of three cases]

Objective: To investigate the clinicopathological features and possible mechanisms of burned-out testicular germ cell tumors. Methods: The clinical and imaging data, histology and immunophenotypic characteristics of three cases of burned-out testicular germ cell tumors diagnosed at the Ruijin Hospital, Medical College of the Shanghai Jiaotong University, from 2016 to 2020 were retrospectively analyzed. The relevant literature was reviewed. Results: The mean age of the three patients was 32 years. Case 1 had an elevated preoperative alpha-fetoprotein level (810.18 μg/L) and underwent "radical pancreaticoduodenectomy and retroperitoneal lesion resection" for a retroperitoneal mass. Postoperative pathology showed embryonal carcinoma, which needed to exclude gonadal metastasis. Color Doppler ultrasound showed a solid mass of the right testis, with hypoechoic lesion and scattered calcification in some areas. Case 2 was a "right supraclavicular lymph node biopsy specimen." Chest X-ray showed multiple metastases in both lungs. The biopsy showed metastatic embryonic carcinoma and bilateral testicular color Doppler ultrasound revealed abnormal calcifications in the right testicle. Case 3 showed a cystic mass of the right testis with calcification and solid areas. All 3 patients underwent radical right orchiectomy. Grossly, borders of the testicular scar areas were well defined. Cross sectioning of the tumors showed a gray-brown cut surface and single focus or multiple foci of the tumor. The tumor maximum diameter was 0.6-1.5 cm. Microscopically, lymphocytes, plasma cells infiltration, tubular hyalinization, clustered vascular hyperplasia and hemosiderin laden macrophages were found in the scar. Atrophic and sclerotic seminiferous tubules, proliferation of clustered Leydig cells and small or coarse granular calcifications in seminiferous tubules were present around the scar. Seminoma and germ cell neoplasia in situ were seen in case 1, germ cell neoplasia in situ was seen in case 2 and germ cells with atypical hyperplasia were seen in case 3. Immunohistochemistry showed that embryonic carcinoma expressed SALL4, CKpan(AE1/AE3) and CD30, seminoma and germ cell tumor in situ expressed OCT3/4, SALL4 and CD117, and spermatogenic cells with atypical hyperplasia expressed CD99 and SALL4. The Ki-67 positive index was about 20%, while OCT3/4 and CD117 were both negative. Conclusions: Burned-out testicular germ cell tumors are rare. The possibility of gonad testicular metastasis should be considered first for extragonadal germ cell tumor. If fibrous scar is found in testis, it must be determined whether it is a burned-out testicular germ cell tumor. The burned-out mechanisms may be related to the microenvironment of tumor immune-mediated and local ischemic injury.

Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 10^{5} and 10^{9}  GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.

Spontaneous Ferromagnetism Induced Topological Transition in EuB_{6}

The interplay between various symmetries and electronic bands topology is one of the core issues for topological quantum materials. Spontaneous magnetism, which leads to the breaking of time-reversal symmetry, has been proven to be a powerful approach to trigger various exotic topological phases. In this Letter, utilizing the combination of angle-resolved photoemission spectroscopy, magneto-optical Kerr effect microscopy, and first-principles calculations, we present the direct evidence on the realization of the long-sought spontaneous ferromagnetism induced topological transition in soft ferromagnetic EuB_{6}. Explicitly, we reveal the topological transition is from Z_{2}=1 topological insulator in paramagnetic state to χ=1 magnetic topological semimetal in low temperature ferromagnetic state. Our results demonstrate that the simple band structure near the Fermi level and rich topological phases make EuB_{6} an ideal platform to study the topological phase physics.

Exploring Lorentz Invariance Violation from Ultrahigh-Energy γ Rays Observed by LHAASO

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.

Gamma-Ray Observation of the Cygnus Region in the 100-TeV Energy Region

We report observations of gamma-ray emissions with energies in the 100-TeV energy region from the Cygnus region in our Galaxy. Two sources are significantly detected in the directions of the Cygnus OB1 and OB2 associations. Based on their positional coincidences, we associate one with a pulsar PSR J2032+4127 and the other mainly with a pulsar wind nebula PWN G75.2+0.1, with the pulsar moving away from its original birthplace situated around the centroid of the observed gamma-ray emission. This work would stimulate further studies of particle acceleration mechanisms at these gamma-ray sources.

Peta-electron volt gamma-ray emission from the Crab Nebula

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10^-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 10³⁶ ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25  TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160  TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 10¹⁵ electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays¹. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. ²). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane^3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

Near-GeV Electron Beams at a Few Per-Mille Level from a Laser Wakefield Accelerator via Density-Tailored Plasma

A simple, efficient scheme was developed to obtain near-gigaelectronvolt electron beams with energy spreads of few per-mille level in a single-stage laser wakefield accelerator. Longitudinal plasma density was tailored to control relativistic laser-beam evolution, resulting in injection, dechirping, and a quasi-phase-stable acceleration. With this scheme, electron beams with peak energies of 780-840 MeV, rms energy spreads of 2.4‰-4.1‰, charges of 8.5-23.6 pC, and rms divergences of 0.1-0.4 mrad were experimentally obtained. Quasi-three-dimensional particle-in-cell simulations agreed well with the experimental results. The dechirping strength was estimated to reach up to 11  TeV/mm/m, which is higher than previously obtained results. Such high-quality electron beams will boost the development of compact intense coherent radiation sources and x-ray free-electron lasers.

Advances in Ultrasound-Guided Vacuum-Assisted Biopsy of Breast Microcalcifications

Microcalcification is one of the significant indications for or can even be the sole mammographic feature of breast cancer, especially occult breast cancer. Biopsy and pathologic examination are the most important methods used to identify the nature of suspicious microcalcifications. Stereotactic vacuum-assisted breast biopsy (S-VAB) is the most commonly used biopsy method for microcalcifications currently because of the high detection rate of mammography for microcalcifications. However, in recent years, several clinical studies have gradually found that ultrasound-guided vacuum-assisted breast biopsy (US-VAB) could be an alternative to S-VAB for microcalcifications to some extent, and has its own advantages of flexibility, real-time performance, comfort and high accessibility compared with mammography. An overview of US-VAB of microcalcifications is provided with respect to success rate, diagnostic accuracy, advantages and limitations. On the basis of numerous studies and clinical experience, US-VAB proved to be a valid alternative to S-VAB, with comparable diagnostic accuracy if the microcalcification foci could be detected by ultrasound. And for patients with ultrasound-invisible microcalcifications who are not suitable for or tolerable of S-VAB, US-VAB combined with mammography localization of microcalcifications can also be considered.

First Detection of sub-PeV Diffuse Gamma Rays from the Galactic Disk: Evidence for Ubiquitous Galactic Cosmic Rays beyond PeV Energies

We report, for the first time, the long-awaited detection of diffuse gamma rays with energies between 100 TeV and 1 PeV in the Galactic disk. Particularly, all gamma rays above 398 TeV are observed apart from known TeV gamma-ray sources and compatible with expectations from the hadronic emission scenario in which gamma rays originate from the decay of π^{0}'s produced through the interaction of protons with the interstellar medium in the Galaxy. This is strong evidence that cosmic rays are accelerated beyond PeV energies in our Galaxy and spread over the Galactic disk.

Association Between Breast and Thyroid Lesions: A Cross-Sectional Study Based on Ultrasonography Screening in China

Introduction: Prior research has shown an association between breast and thyroid cancers, although their relationship is unclear. In China, asymptomatic women undergoing regular health checkups usually undergo breast and thyroid ultrasonography screening. The present cross-sectional ultrasound-based study estimated the prevalence of breast masses (BM) and thyroid nodules (TN) and their relationship among a population-based cohort of Chinese women. Methods: This study included 34,184 consecutive asymptomatic Chinese women who underwent both breast and thyroid ultrasound evaluation during one health care examination. Detected lesions were assigned into categories of different malignant risks according to the Breast and Thyroid Imaging Reporting and Data System (BI-/TI-RADS). Binomial logistic regression was used to determine the association between occurrence of BM and TN, and multinomial logistic regression was used to analyze the correlation of BM and TN in different BI-/TI-RADS categories. Associations between BM and TN, as well as anthropometric and biochemical markers, were also explored. Results: Of those enrolled, 6371 (18.6%) had BM, 12,153 (35.6%) had TN, and 2279 (6.7%) had both. After adjusting for age, body mass index (BMI), and height, females with TN had a higher risk of BM (odds ratio [OR] = 1.151, 95% confidence interval [CI 1.081-1.225], p < 0.0001) than those with normal thyroids, and females with BM had a higher risk of TN (OR = 1.165 [CI 1.096-1.238], p < 0.0001) than those without BM. Women with a TN >10 mm (OR = 1.249 [CI 1.104-1.413], p = 0.0004) and those with a TN ≤10 mm (OR = 1.134 [CI 1.062-1.211], p = 0.0002) were at higher risk of BM compared with those with normal thyroids. As RADS categories increased, so did the correlation between BM and TN. The increased risk of TN was associated with a higher BMI, height, systolic blood pressure, and a lower plasma albumin level. The increased risk of BM was associated with a lower BMI, plasma albumin levels, and higher height. Conclusions: A high prevalence of BM and TN was detected by ultrasonography screening in this cohort of Chinese women. These lesions occurred frequently and simultaneously, particularly in women with lesions in higher RADS categories.

Clinical study on the status of transient thyrotoxicosis after surgery for secondary hyperparathyroidism patients with end-stage renal disease and normal thyroid function

Objective

Secondary hyperparathyroidism (SHPT) is a common complication of end-stage renal disease (ESRD), and part of SHPT patients need receive parathyroidectomy (PTX). However, as an important postoperative complication of SHPT, thyrotoxicosis has received little attention. Therefore, in this article, we aimed to study the status of transient thyrotoxicosis after PTX for SHPT patients with ESRD and normal thyroid function.

Methods

A total of 24 SHPT patients with preoperative normal thyroid function, normal thyroglobulin (Tg) and normal thyroid antibodies receiving PTX were enrolled from the Department of Endocrine and Breast Surgery, the First Affiliated Hospital of Chongqing Medical University, from January 2017 to January 2019. Tg, high sensitivity thyrotropin stimulating hormone (sTSH), triiodothyronine (T3), free triiodothyronine (fT3), thyroxine (T4) and free thyroxine (fT4) were evaluated the day before PTX and on day 1, 3 and 5 after PTX. Besides, all enrolled patients were evaluated whether there are symptoms associated with thyrotoxicosis.

Results

Among the 24 SHPT patients, 1 case (4.2%), 8 cases (33.3%) and 13 cases (54.2%) had suffered thyrotoxicosis at the first, third and fifth day after surgery, respectively. Serum FT4 level increased significantly from pre-operation (0.68 ± 0.15 ng/dl, normal range 0.59–1.25 ng/dl) to the third day after operation (1.91 ± 0.97 ng/dl, p<0.001) and then gradually decline. The frequencies of serum sTSH lower than the normal level gradually increased from the first day (8.3%) to fifth day (66.7%) after surgery.

Conclusion

Transient thyrotoxicosis is a common postoperative complication of parathyroidectomy for SHPT patients with ESRD and normal thyroid function, and it is necessary for clinicians to evaluate the perioperative thyroid function to make early diagnosis and appropriate prevention and treatment of thyrotoxicosis.

Cognitive impairments in breast cancer survivors treated with chemotherapy: a study based on event-related potentials

PURPOSE

Chemotherapy-related cognitive impairments in breast cancer patients were usually reported through cognitive questionnaires or scales which may be subjective and insensitive. This study is to assess the effect of chemotherapy on cognitive function in breast cancer patients stratified by age using objective electrophysiological measure, the P300 component of event-related potentials (ERPs) with a large sample size.

METHODS

Totally, 529 primary breast cancer patients, including 178 cases at initial diagnosis stage and before chemotherapy (Group1), 167 cases during chemotherapy (Group2), and 184 cases post chemotherapy and during follow-up period (Group3), were examined with ERPs (P300 component) to assess the effect of chemotherapy on their cognitive function.

RESULTS

There were significant differences of P300 latency in Group2 (364.74 ± 15.73 ms) and Group3 (364.02 ± 17.12 ms, mean follow-up period of 2.42 years) compared with Group1 (355.13 ± 19.47 ms, P < 0.001), respectively. With further age stratification: in patients of < 50 years, P300 latency was significantly prolonged in Group2 and Group3 compared with Group1 (P < 0.001), respectively; in patients of 50-59 years, P300 latency was significantly prolonged in Group2 compared with Group1 (P < 0.05), but without difference in Group1 and Group3 (P>0.05); In patients of ≥ 60 years, there were no differences of P300 latency among three the groups (P>0.05).

CONCLUSIONS

It is first suggested by our objective detection data that the side effect of chemotherapy on cognitive functions in breast cancer patients may decrease with age. Electrophysiological cognitive impairments mainly occur in younger breast cancer patients undergoing chemotherapy and would last for years after chemotherapy, which highlights the importance of early intervention for those patients, especially in younger patients.

First Detection of Photons with Energy beyond 100 TeV from an Astrophysical Source

We report on the highest energy photons from the Crab Nebula observed by the Tibet air shower array with the underground water-Cherenkov-type muon detector array. Based on the criterion of a muon number measured in an air shower, we successfully suppress 99.92% of the cosmic-ray background events with energies E>100  TeV. As a result, we observed 24 photonlike events with E>100  TeV against 5.5 background events, which corresponds to a 5.6σ statistical significance. This is the first detection of photons with E>100  TeV from an astrophysical source.

Expression of vitamin D receptor in renal tissue of lupus nephritis and its association with renal injury activity

Objective

Vitamin D receptor (VDR) has potent anti-inflammatory activities. VDR gene polymorphism has been linked with systemic lupus erythematosus (SLE). However, its expression in the kidney has not been evaluated. This study aimed to investigate the relationship between VDR expression and renal pathology as well as clinical manifestations in lupus nephritis (LN).

Methods

A total of 20 renal biopsy specimens from 35 patients with LN were classified according to the International Society of Nephrology/Renal Pathology Society 2003 LN-type standards pathological type, and the activity index and chronicity index were determined. Five normal renal tissue samples were obtained from surrounding areas distal to nephronophthisis or renal tumors (>2 cm). The expression of VDR was assessed by immunohistochemistry. The relationships between VDR expression and histological injury index, proteinuria and Systemic Lupus International Collaborating Clinics (SLICC) renal activity scores were analyzed.

Results

As compared to the control group, the expression of VDR in the LN group was lower ( p < 0.001) and negatively correlated with activity index (r = –0.548, p = 0.012) but not with chronicity index (r = –0.277, p = 0.236). The expression of VDR in renal tissue was also associated with SLICC renal activity scores (r = –0.470, p = 0.037).

Conclusion

The down-regulation of VDR expression in renal tissues of LN patients was negatively correlated with renal activity and injury severity.

[Expression patterns and prognostic values of Nrf2 and Keap1 in nasopharyngeal carcinoma]

Objective:To investigate the expression of Nrf2 and Keap1 in nasopharyngeal carcinoma (NPC) and to analyze the relationship between the expression of Nrf2 and Keap1 and the clinicopathological features and prognosis of patients with nasopharyngeal carcinoma. Method:A total of 108 patients with biopsy-proven nonkeratinizing squamous cell carcinoma-undifferentiated type with available biopsy specimens for tissue microarray (TMA) construction were selected. The relationship between Nrf2 and Keap1 protein expression and the prognosis of radiotherapy in patients with nasopharyngeal carcinoma was analyzed. Result: The overall 5-year disease free survival (DFS) and overall survival(OS) rates were 57.4% and 70.2%, respectively. The 5-year DFS rate was 59.4% in the low nuclear Nrf2 expression group, and 53.8% in the high nuclear Nrf2 expression group. The 5-year DFS rate was 42.2% in the low cytoplasmic Keap1 expression group, and 68.2% in the high cytoplasmic Keap1 expression group. The 5-year OS rate was 70.8% in the low nuclear Nrf2 expression group, and 69.2% in the high nuclear Nrf2 expression group. The 5-year OS rate was 55.6% in the low cytoplasmic Keap1 expression group, and 80.9% in the high cytoplasmic Keap1 expression group.Conclusion:We found that nuclear Nrf2 or cytoplasmic Keap1 expression had no significant association with clinicopathological features. The high expression of cytoplasmic Keap1 had higher DFS and OS. Keap1 is an independent prognostic factor for DFS and OS in NPC patient.

Evaluation of the Interplanetary Magnetic Field Strength Using the Cosmic-Ray Shadow of the Sun

We analyze the Sun's shadow observed with the Tibet-III air shower array and find that the shadow's center deviates northward (southward) from the optical solar disk center in the "away" ("toward") interplanetary magnetic field (IMF) sector. By comparing with numerical simulations based on the solar magnetic field model, we find that the average IMF strength in the away (toward) sector is 1.54±0.21_{stat}±0.20_{syst} (1.62±0.15_{stat}±0.22_{syst}) times larger than the model prediction. These demonstrate that the observed Sun's shadow is a useful tool for the quantitative evaluation of the average solar magnetic field.

[Initial study of transthoracic echocardiography guided three-dimensional printing on the application of assessment of structural heart disease]

Objective: To investigate the feasibility and diagnostic value of preoperative transthoracic echocardiography guided three dimensional printing model (TTE Guided 3DPM) on the assessment of structural heart disease (SHD). Methods: From February 2016 to October 2016, 44 patients underwent cardiac surgery in Tianjin Chest Hospital, forty-four patients were assessed preoperatively using TTE Guided 3DPM, including 25 males and 19 females, aged 3-75 years, with an average of (44±22) years. compared to conventional three dimensional transthoracic echocardiography (3D-TTE), and took direct intraoperative findings as "Golden Standard" simultaneously. There are twelve patients with SHD, including four cases with mitral prolapse, two cases with partial endocardial cushion defect, two cases with secondary atrial septal defect, two cases with rheumatic mitral stenosis, one case with tetralogy of Fallot, one case with ventricular septal defect (VSD), thirty-two patients without SHD were designed as negative control. Results: The sensitivity and specificity of TTE Guided 3DPM were greater than or equal to 3D-TTE, P value of McNemar test of 3D-TTE was greater than 0.05, the difference was not statistically significant, kappa=0.745, P<0.01, indicated that the results of 3DTTE and the gold standard were generally consistent.P value of McNemar test of TTE Guided 3DPM was greater than 0.05, the difference was not statistically significant, kappa=0.955, P<0.01, indicated that the results of TTE Guided 3DPM and gold standards were consistent. Compared with 3D-TTE and TTE Guided 3DPM, P value was greater than 0.05, the difference was not statistically significant, kappa=0.879, P<0.01, indicated that the results of 3D-TTE and TTE Guided 3DPM were consistent. TTE Guided 3DPM displayed the three-dimensional structure of SHD cardiac lesions clearly, which were consistent with intraoperative findings. Conclusion: TTE Guided 3DPM provides essential information for the preoperative evaluation and decision of SHD.

[The multicenter study on the registration and follow-up of low anticoagulation therapy for the heart valve operation in China]

OBJECTIVE

To investigate the optimal anticoagulation methods and monitoring strategy for Chinese patients undergoing heart valve replacement, which is potentially quite different from western populations.

METHODS

In this multicenter prospective cohort study, the anticoagulation and monitoring strategy data was acquired from 25 773 in-hospital patients in 35 medical centers and 20 519 patients in outpatient clinic in 11 medical centers from January 1st, 2011 to December 31th, 2015.

RESULTS

As for in-hospital patients, mean age of study population was (48.6±11.2) years old; main etiology of valve pathology was rheumatic (87.5%) origin among study cohort; 94.8% of study population received mechanical valve implantation; international normalized ratio (INR) monitoring (in all the study centers) and low-intensity anticoagulation strategy (31 hospitals chose target INR range of 1.5-2.5, and actual values of INR among 89.2% of 100 069 in-hospital monitoring samples were 1.5-2.5), with mean actual INR values of 1.84±0.53, and warfarin dosage of (2.82±0.93) mg/d were widely adopted among the study centers; strategies of in-hospital warfarin administration were similar in all the study centers; complication rates of low-intensity anticoagulation strategy were low in severe hemorrhage (0.02%), thrombosis (0.05%), and thromboembolism (0.05%) events, without anticoagulation-related death.As for 18 974 outpatient clinic patients, the follow-up rate was 92.47%, with a total of 30 012 patient-years (Pty). Anticoagulation-related morbidity and mortality rates were 0.67% and 0.15% Pty; major hemorrhage morbidity and mortality rates were 0.25% and 0.13% Pty; thromboembolism morbidity and mortality rates were 0.45% and 0.03% Pty.The mean dosage of warfarin daily dosage was (2.85±1.23) mg/d and INR value was 1.82±0.57.No significant regional difference in the intensity of anticoagulation therapy was noted during the study.

CONCLUSIONS

INR can be used as a normalized indicator for intensity of anticoagulation therapy in China.The optimal anticoagulation intensity with INR range from 1.5 to 2.5 is safe and effective for Chinese patients with heart valve replacement, and there is no significant regional difference in the intensity of anticoagulation therapy.

Generalized R-squared for detecting dependence

Detecting dependence between two random variables is a fundamental problem. Although the Pearson correlation coefficient is effective for capturing linear dependence, it can be entirely powerless for detecting nonlinear and/or heteroscedastic patterns. We introduce a new measure, G-squared, to test whether two univariate random variables are independent and to measure the strength of their relationship. The G-squared statistic is almost identical to the square of the Pearson correlation coefficient, R-squared, for linear relationships with constant error variance, and has the intuitive meaning of the piecewise R-squared between the variables. It is particularly effective in handling nonlinearity and heteroscedastic errors. We propose two estimators of G-squared and show their consistency. Simulations demonstrate that G-squared estimators are among the most powerful test statistics compared with several state-of-the-art methods.

Role of XRCC1 gene polymorphisms in non-small cell lung cancer cisplatin-based chemotherapy, and their effect on clinical and pathological characteristics

Non-small cell lung cancer (NSCLC) is the most common cancer globally. The XRCC1 protein interacts with ligase and poly(ADP-ribose) polymerase to repair cisplatin-induced DNA damage. The authors of previous studies have reported XRCC1 Arg399Gln, Arg280His, and Arg194Trp polymorphisms and advanced NSCLC prognosis, but the results are inconclusive. We investigated the association between clinical outcome and XRCC1 Arg399Gln, Arg280His, and Arg194Trp polymorphisms in advanced NSCLC patients treated with cisplatin. We recruited 252 patients with advanced NSCLC (TNM stages: IIIB and IV) and used polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to genotype the polymorphisms. Patients with the TT genotype of XRCC1 Arg194Trp showed a significantly better response to chemotherapy than those with the CC genotype. The GA+AA genotype of Arg194Trp was correlated with better response to chemotherapy than the wild-type form. The TT genotype of Arg194Trp was associated with longer survival time than the CC genotype. The TT genotype of Arg194Trp was correlated with lower risk of death from all causes than the CC genotype. The Arg194Trp polymorphisms interacted with squamous cell carcinoma and affected overall survival of advanced NSCLC. However, there was no association between Arg399Gln and Arg280His polymorphisms and response to cisplatin-based chemotherapy and overall survival in advanced NSCLC. The results suggest that the TT genotype of Arg194Trp is significantly associated with better response to chemotherapy and longer overall survival of advanced NSCLC patients than the wild-type form. Our investigation offers insight into the influence of XRCC1 gene polymorphisms on the treatment outcome of advanced NSCLC.

Genetic Polymorphisms of 21 STR Loci in Hunan Province-based Han Population

OBJECTIVES

To investigate the genetic polymorphisms of 21 short tandem repeat （STR） loci （D3S1358, D13S317, D7S820, D16S539, Penta E, D2S441, TPOX, TH01, D2S1338, CSF1PO, Penta D, D10S1248, D19S433, vWA, D21S11, D18S51, D6S1043, D8S1179, D5S818, D12S391 and FGA）.

METHODS

A total of 560 blood samples were collected from unrelated healthy individuals of Han population in Hunan Province. Chelex-100 extraction method was applied to the extraction of genomic DNA, and an AGCU EX22 Kit and 9700 STR amplification was used in amplification reactions. The products were separated and analyzed on 310 Genetic Analyzer.

RESULTS

A total of 248 alleles were observed, the allelic frequencies ranging from 0.001 to 0.518. Observation of genotype distributions for each locus showed no deviations from Hardy-Weinberg equilibrium except Penta E （P=0.023）. The combined power of discrimination, combined power of exclusion, and combined matching probability of the 21 STR loci were approximately 0.999 999 999 999 999 999 999 999 8, 0.999 999 998, and 1.36×10⁻²⁵, respectively.

CONCLUSIONS

The 21 STR loci show high polymorphisms in the Han population, which can provide valuable data and a theoretical basis for forensic individual identification and paternity testing.

High-Brightness High-Energy Electron Beams from a Laser Wakefield Accelerator via Energy Chirp Control

By designing a structured gas density profile between the dual-stage gas jets to manipulate electron seeding and energy chirp reversal for compressing the energy spread, we have experimentally produced high-brightness high-energy electron beams from a cascaded laser wakefield accelerator with peak energies in the range of 200-600 MeV, 0.4%-1.2% rms energy spread, 10-80 pC charge, and ∼0.2  mrad rms divergence. The maximum six-dimensional brightness B_{6D,n} is estimated as ∼6.5×10^{15}  A/m^{2}/0.1%, which is very close to the typical brightness of e beams from state-of-the-art linac drivers. These high-brightness high-energy e beams may lead to the realization of compact monoenergetic gamma-ray and intense coherent x-ray radiation sources.

Serum levels of S-100β correlate with the clinical status and severity of hypoxic-ischemic encephalopathy in neonates

The clinical significance of serum S-100β levels in neonates with hypoxic-ischemic encephalopathy (HIE), as a reference index to assess HIE severity, was evaluated in this study. On the basis of our strict inclusion and exclusion criteria, relevant high-quality case-control studies reporting the association between HIE and S-100β protein were selected from electronic database searches. The STATA version 12.0 software was used for the statistical analyses. The database search initially retrieved 93 studies (37 in English and 56 in Chinese), and following a multistep screening process, 13 high-quality studies were eventually included in our meta-analysis. The 13 case-control studies included a total of 646 HIE neonates and 381 healthy controls. The results of this meta-analysis revealed that serum S-100β levels in mild, moderate, and severe HIE neonates were significantly higher than those in healthy controls, and the differences were statistically significant. Importantly, the serum S-100β levels increased incrementally with HIE severity. Our results support the hypothesis that S-100β is an important biological indicator of HIE and serum S-100β levels can be used as a reference index to assess HIE severity.

p-type doping of MgZnO films and their applications in optoelectronic devices

A lithium and nitrogen codoping method has been employed to prepare p-type MgZnO films, and p-MgZnO/i-ZnO/n-ZnO structured light-emitting devices (LEDs) and photodetectors have been fabricated. The LEDs can work continuously for about 97 h under the injection of a 20 mA continuous current, which is the best value ever reported for ZnO-based LEDs. The performance of the photodetectors degrades little after several running cycles. The above results reveal the applicability of the p-MgZnO films in optoelectronic devices.

Gene-expression data integration to squamous cell lung cancer subtypes reveals drug sensitivity

BACKGROUND

Squamous cell lung cancer (SqCC) is the second most common type of lung cancer in the United States. Previous studies have used gene-expression data to classify SqCC samples into four subtypes, including the primitive, classical, secretory and basal subtypes. These subtypes have different survival outcomes, although it is unknown whether these molecular subtypes predict response to therapy.

METHODS

Here, we analysed RNAseq data of 178 SqCC tumour samples and characterised the features of the different SqCC subtypes to define signature genes and pathway alterations specific to each subtype. Further, we compared the gene-expression features of each molecular subtype to specific time points in models of airway development. We also classified SqCC-derived cell lines and their reported therapeutic vulnerabilities.

RESULTS

We found that the primitive subtype may come from a later stage of differentiation, whereas the basal subtype may be from an early time. Most SqCC cell lines responded to one of five anticancer drugs (Panobinostat, 17-AAG, Irinotecan, Topotecan and Paclitaxel), whereas the basal-type cell line EBC-1 was sensitive to three other drugs (PF2341066, AZD6244 and PD-0325901).

CONCLUSION

Compared with the other three subtypes of cell lines, the secretory-type cell lines were significantly less sensitive to the five most effective drugs, possibly because of their low proliferation activity. We provide a bioinformatics framework to explore drug repurposing for cancer subtypes based on the available genomic profiles of tumour samples, normal cell types, cancer cell lines and data of drug sensitivity in cell lines.

Probe of the solar magnetic field using the "cosmic-ray shadow" of the sun

We report on a clear solar-cycle variation of the Sun’s shadow in the 10 TeV cosmic-ray flux observed by the Tibet air shower array during a full solar cycle from 1996 to 2009. In order to clarify the physical implications of the observed solar cycle variation, we develop numerical simulations of the Sun’s shadow, using the potential field source surface model and the current sheet source surface (CSSS) model for the coronal magnetic field. We find that the intensity deficit in the simulated Sun’s shadow is very sensitive to the coronal magnetic field structure, and the observed variation of the Sun’s shadow is better reproduced by the CSSS model. This is the first successful attempt to evaluate the coronal magnetic field models by using the Sun’s shadow observed in the TeV cosmic-ray flux.

Sorafenib combined with transarterial chemoembolization for the treatment of advanced hepatocellular carcinoma: a large-scale multicenter study of 222 patients

BACKGROUND

Data on the efficacy and safety of sorafenib in combination with transarterial chemoembolization (TACE) in patients with advanced hepatocellular carcinoma (HCC) are lacking.

PATIENTS AND METHODS

In this multicenter retrospective study, 222 consecutive HCC patients receiving combination therapy were enrolled between June 2008 and July 2011.

RESULTS

Chronic hepatitis B was the predominant cause of HCC (86%). Eighty percent patients were at Barcelona Clinic Liver Cancer (BCLC) stage C, and 86% patients were in Child-Pugh (CP) A class. The overall median survival was 12 months (95% CI 10.1-13.9). The overall incidence of adverse events (AEs) was 87%. In 177 BCLC-C patients, performance status, the number of HCC nodules, Child-Pugh score and macrovascular invasion were significantly associated with overall survival (OS) and were included in the final risk scores (R), where R = 5 × (vascular invasion: 0 if no, 1 yes) + 6 × (CP: 0 if A, 1 if B) + 7 × (no. of lesions: 0 if 1-2, 1 ≥3) + 8 × ( Eastern Cooperative Oncology Group, ECOG: 0 if 0, 1 ≥1).

CONCLUSIONS

Sorafenib in combination with TACE should be considered a safe and effective therapy for advanced HCC. Further validation of the new subgroup of BCLC-C stage is warranted in an independent patient cohort.

Energy, amino acid, and phosphorus digestibility of phytase transgenic corn for growing pigs

Three experiments were conducted to evaluate energy, AA, and P digestibility in a phytase transgenic corn (PTC) containing a phytase gene (phyA2) isolated from Aspergillus niger compared with a nontransgenic near-isoline conventional corn (CC) grown in the same environmental conditions for growing pigs. Experiment 1 was an energy balance experiment conducted to measure DE and ME in PTC and CC. Eighteen growing barrows (initial BW 25.8±0.3 kg) from 9 litters were allotted by BW and litter to 1 of 2 dietary treatments with 9 pigs per treatment in a randomized complete block design. Pigs were individually placed in metabolism cages and fed diets based on the 2 corns. The DE and ME in PTC (3,967 and 3,941 kcal/kg of DM, respectively) were greater (P<0.05) than those in CC (3,917 and 3,848 kcal/kg of DM, respectively). Experiment 2 was conducted to measure apparent ileal digestibility (AID) and standardized ileal digestibility (SID) values of CP and AA in the 2 corns. Eighteen growing barrows (initial BW 41.8±0.7 kg) were equipped with a T-cannula in the distal ileum. Pigs were placed in metabolism cages in a completely randomized design with 3 dietary treatments of 6 pigs each. An N-free diet was used to estimate basal endogenous losses of CP and AA. The AID and SID values for CP and all AA did not differ between the 2 corns. Experiment 3 was conducted to measure apparent total tract digestibility (ATTD) and standardized total tract digestibility (STTD) values of P in the 2 corns. Eighteen growing pigs (initial BW 30.5±0.5 kg) from 6 litters were placed in metabolism cages in a randomized complete block design with 3 dietary treatments of 6 pigs each based on BW and litter. Two diets were based on the 2 corns, and a P-free diet was used to measure endogenous P losses. The ATTD and STTD values of P were greater (P<0.05) in the PTC diet (71.4% and 76.9%, respectively) than those in the CC diet (27.6% and 33.4%, respectively). Pigs fed the PTC diet had a greater (P<0.05) P retention (70.7%) than those fed the CC diet (27.1%). It was concluded that PTC had a greater digestibility of energy and P than CC for growing pigs. As a consequence, if PTC replaces CC in a pig diet, the DE and ME in the diet will increase, and less inorganic P will need to be supplemented to the diet, and thus P excretion in manure will be decreased.

Maximum thickness of subarachnoid blood is associated with mortality in patients with traumatic subarachnoid haemorrhage

This study was designed to evaluate whether the maximum thickness of subarachnoid blood is an independent prognostic marker of mortality after traumatic subarachnoid haemorrhage. Multivariate analysis showed the maximum thickness of subarachnoid blood was an independent predictor of death versus survival 1 month after injury and was inversely associated with Glasgow Coma Scale (GCS) score. Receiver operating characteristic curve analysis showed that maximum thickness of subarachnoid blood > 6.7 mm immediately after non-surgical resuscitation predicted 1-month mortality with 83.9% sensitivity and 67.1% specificity; its predictive value was similar to that of the GCS score. Addition of maximum thickness of subarachnoid blood to the GCS score did not significantly improve predictive performance. Hence, the maximum thickness of subarachnoid blood is a new independent prognostic marker of mortality and might become an additional, valuable tool for risk stratification and decision making in the acute phase of traumatic subarachnoid haemorrhage.

Slot optical waveguide usage in forming passive optical devices

We have reviewed the work on SOI slot optical waveguides followed by our work. In a slot waveguide structure, light can be confined in a low index slot guarded by high index slabs. Slot structures are being used in forming complex structures; such as ring resonator circuits. The increased round trip in ring resonator circuits signifies the importance of dispersion calculations. We did analytical and numerical investigations of slot structures' dispersion characteristics. Our dispersion tuned slot structures can help in reducing the dispersion effects on optical signal, which will in turn improve the efficiency of light-on-chip circuits. Since the advent of slot optical waveguides, SOI based slot optical waveguides have been under consideration. It has been found that glass based slot optical waveguide structures with relatively low refractive index contrast ratio can also play an important role in forming complex nano-size optical devices. We made use of power confined inside low index slot regions for a double slot structure. Opto-mechanical sensors have been proposed based upon: (a) variation in power confined inside low index slot region due to the movement of central high index slab under the action of external force (temperature, pressure, humidity, etc). vide Chinese Patent No. ZL 200710176770.1, 2007 (b) variation in power confined inside low refractive index slot regions due to movement of both slots under the action of external force (temperature, pressure, humidity, etc).

A new inducible expression system in a transformed green alga, Chlorella vulgaris

Genetic transformation is useful for basic research and applied biotechnology. However, genetic transformation of microalgae is usually quite difficult due to the technical limitations of existing methods. We cloned the promoter and terminator of the nitrate reductase gene from the microalga Phaeodactylum tricornutum and used them for optimization of a transformation system of the microalga Chlorella vulgaris. This species has been used for food production and is a promising candidate as a bioreactor for large-scale production of value-added proteins. A construct was made containing the CAT (chloramphenicol acetyltransferase) reporter gene driven by the nitrate reductase promoter. This construct was transferred into the C. vulgaris genome by electroporation. Expression of CAT in transgenic Chlorella conferred resistance to the antibiotic chloramphenicol and enabled growth in selective media. Overall efficiency for the transformation was estimated to be approximately 0.03%, which is relatively high compared with other available Chlorella transformation systems. Expression of CAT was induced in the presence of nitrate and inhibited in the presence of ammonium as a sole nitrogen source. This study presented an inducible recombinant gene expression system, also providing more gene regulation elements with potential for biotechnological applications.

Association of Interleukin-11 with Mortality in Patients with Spontaneous Basal Ganglia Haemorrhage

This study evaluated interleukin (IL)-11 as an independent prognostic marker of mortality following intracerebral haemorrhage (ICH). Plasma IL-11 levels in patients with ICH were significantly higher than in healthy controls. Multivariate analysis indicated that plasma IL-11 level was an independent predictor for mortality within 1 week of ICH onset and was positively associated with haematoma volume. Receiver operating characteristic curve analysis identified that a baseline plasma IL-11 level > 20.9 pg/ml predicted mortality within 1 week of ICH onset with 81.2% sensitivity and 74.1% specificity. The area under the curve for IL-11 level was significantly smaller than that for the Glasgow Coma Scale score, but similar to that for haematoma volume. IL-11 did not, however, significantly improve the predictive value of the Glasgow Coma Scale or haematoma volume. Thus, IL-11 may be considered as a new independent prognostic marker of mortality and an additional valuable tool for risk stratification and decision-making in the acute phase of ICH.

All-optical cascaded laser wakefield accelerator using ionization-induced injection

We report on near-GeV electron beam generation from an all-optical cascaded laser wakefield accelerator (LWFA). Electron injection and acceleration are successfully separated and controlled in different LWFA stages by employing two gas cells filled with a He/O2 mixture and pure He gas, respectively. Electrons with a Maxwellian spectrum, generated from the first LWFA assisted by ionization-induced injection, were seeded into the second LWFA with a 3-mm-thick gas cell and accelerated to be a 0.8-GeV quasimonoenergetic electron beam, corresponding to an acceleration gradient of 187  GV/m. The demonstrated scheme paves the way towards the multi-GeV laser accelerators.

Time-dependent theoretical model for terahertz wave detector using a parametric process

We have presented a time-dependent theoretical model to describe the time behavior of a quasi-monochromatic nanosecond terahertz detector reported by Guo et al. [Appl. Phys. Lett. 93, 021106 (2008)]. The temporal input-output characteristic of the detector is investigated numerically by taking the system parameters close to the experimental ones, and the calculated pulse width for the incident terahertz wave agrees well with the experimental one. Our results demonstrate that the energy and width of an output idler wave pulse are proportional to those of the incident terahertz wave pulse. This study provides a strict theoretical basis and could be used to guide the design and optimization for the highly sensitive coherent terahertz detector.

Episodic pain syndrome restricted cheiro-oral region associated with pontine lesion

Other than from the thalamus and sensory cortex, episodic pain is an extremely rare neurological manifestation in the central compartment. This study reports a middle-aged man who experienced an acute onset of episodic oscillatory burning pain restricted to the cheiro-oral region, who was found to have a singular infarct at the left tegmental pons. A close relationship between his pain attack and an elevation of arterial blood pressure was clearly observed. Blood adenohypophyseal hormones and electroencephalogram did not reveal an abnormality in the ictus. Neuroimaging and clinical studies did not support involvement of the thalamus, periaqueductal gray matter, hypothalamus or regional structure. Therefore, episodic pain may be an isolated manifestation with a pontine lesion. A relapsing expansion of focal cerebral oedema with fluid retention may have corresponded to the oscillation of his sensory deficit. This accumulating, devastating calamity by a repetitive and paroxysmal offense after a blood-brain barrier breakdown should be cautiously reviewed.

C-reactive protein predicts ischaemic stroke in haemodialysis patients

Dialysis patients have a higher incidence of cerebrovascular events compared with the general population. However, the value of C-reactive protein (CRP) in predicting stroke in chronic haemodialysis patients is unknown. The aim of this study was to determine the association between serum CRP levels and ischaemic stoke in chronic haemodialysis patients. We retrospectively reviewed 391 chronic haemodialysis patients between November 2001 and November 2004. Patients who developed acute ischaemic stroke within 36-month were recorded. Patients who had lacunar infarction discovered accidentally during brain computed tomography or magnetic resonance imaging scans were recorded for subgroup analysis. The relation of predialysis serum CRP levels, measured via the nephelometric method, to the development of acute ischaemic stroke was analysed using Kaplan-Meier analysis. Factors related to lacunar infarctions were analysed by multivariate logistic regression. Of the 391 patients, 21 developed acute stroke and 24 had lacunar infarction. Kaplan-Meier analysis showed that patients with a serum CRP > 0.8 mg/dl were at risk of developing acute infarction (p = 0.002). In the Cox regression model adjusted for age, cardiovascular disease, hypertension and diabetes, patients with serum CRP > 0.8 mg/dl are at risk of developing acute ischaemic stroke (p = 0.03). In multivariate logistic regression with adjusted for age, hypertension and diabetes, serum CRP levels significantly associated with lacunar infarction (p = 0.05). Serum CRP levels, independent of cardiovascular disease, age, hypertension and diabetes, are associated with the development of acute ischaemic stroke and lacunar infarct in chronic haemodialysis patients.

Serotonin transporter gene promoter polymorphism is associated with body mass index and obesity in non-elderly stroke patients

BACKGROUND

The serotonergic system is involved in the complex behavioral and physiological process in maintaining energy balance. Genetic factors regulating serotonergic function may have links with the development of obesity.

AIM

To investigate whether the 5-HTTLPR polymorphism of the serotonin transporter gene is associated with body mass index (BMI) and obesity in stroke patients.

SUBJECTS AND METHODS

The study included 376 patients (65.3+/-11.3 yr; male, 61.7%) with stroke. Associations between the 5-HTTLPR and BMI and obesity (BMI > or = 25 kg/m2) were examined in all subjects. In order to test age-dependent effects of the genetic variant, the association was also examined in the non-elderly subgroup (<65 yr) and the elderly subgroup (> or =65 yr) respectively.

RESULTS

For non-elderly subjects, the SS genotype was independently associated with increased BMI level (beta=1.84, p=0.037) and obesity (odds ratio 4.17, 95% CI 1.25-14.0, p=0.021) when the LL genotype was used as the reference. The association was not found for all patients or in the elderly subgroup. The LS genotype was not different from the LL genotype in BMI level or risk of obesity, either for all subjects or with regard to the non-elderly and elderly subgroups.

CONCLUSIONS

The SS genotype of 5-HTTLPR is an independent determinant of increased BMI level and obesity in non-elderly stroke patients but not in elderly patients. An age-dependent modification for the effect of the 5-HTTLPR on development of obesity is considered.

Terahertz emission from tubular pB(Zr,Ti)O3 nanostructures

We report intense terahertz emission from lead zirconate titanate (PZT) tubular nanostructures, which have a wall thickness around 40 nm and protrude on n-type Si substrates. Such emission is totally absent in flat PZT films or bulk; hence the effect is attributed to the nanoscale geometry of the tubes. The terahertz radiation is emitted within 0.2 ps, and the spectrum exhibits a broad peak from 2 to 8 THz. This is a gap in the frequency spectrum of conventional semiconductor terahertz devices, such as ZnTe, and an order of magnitude higher frequency peak than that in the well-studied p-InAs, due to the abnormally large carrier concentration gradient in the nanostructured PZT. The inferred mechanism is optical rectification within a surface accumulation layer, rather than the Dember effect. The terahertz emission is optically pumped, but since the tubes exhibit ferroelectric switching, electrically driven emission may also be possible. EPR reveals 02 molecules adsorbed onto the nanotubes, which may play some role in the emission.

Comparison of simulated quenching algorithms for design of diffractive optical elements

We compare the performance of very fast simulated quenching; generalized simulated quenching, which unifies classical Boltzmann simulated quenching and Cauchy fast simulated quenching; and variable step size simulated quenching. The comparison is carried out by applying these algorithms to the design of diffractive optical elements for beam shaping of monochromatic, spatially incoherent light to a tightly focused image spot, whose central lobe should be smaller than the geometrical-optics limit. For generalized simulated quenching we choose values of visiting and acceptance shape parameters recommended by other investigators and use both a one-dimensional and a multidimensional Tsallis random number generator. We find that, under our test conditions, variable step size simulated quenching, which generates each parameter's new states based on the acceptance ratio instead of a certain theoretical probability distribution, produces the best results. Finally, we demonstrate experimentally a tightly focused image spot, with a central lobe 0.22-0.68 times the geometrical-optics limit and a relative sidelobe intensity 55%-60% that of the central maximum intensity.

Identification of anisakid nematodes with zoonotic potential from Europe and China by single-strand conformation polymorphism analysis of nuclear ribosomal DNA

Using genetic markers defined previously in the second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA (rDNA), isotopic, and non-isotopic polymerase-chain-reaction-coupled single-strand conformation polymorphism (SSCP) were utilized to identify each of three anisakid species [Anisakis simplex (s.l.), Contracaecum osculatum (s.l.), and Hysterothylacium aduncum] from different host species and geographical locations in Poland and Sweden. While subtle microheterogeneity was observed within each of Anisakis simplex (s.l.) and H. aduncum, distinct SSCP profiles were displayed for each of the three species, allowing identification and differentiation of the three taxa. Subsequent sequencing of the ITS-1 and ITS-2 rDNA revealed that A. simplex (s.l.) represented Anisakis simplex s.s. and Contracaecum osculatum (s.l.) represented C. osculatum C. Application of the non-isotopic SSCP assay of ITS-2 to larval anisakid samples from different hosts and geographical locations in China revealed three distinct SSCP profiles, one of which was consistent with that of A. simplex (s.l.), and the other two had different SSCP profiles from that of C. osculatum C and H. aduncum. Sequencing of the ITS-1 and ITS-2 rDNA for representative Chinese anisakid samples examined revealed three anisakid species in China, i.e., Anisakis typica, Anisakis pegreffii, and Hysterothylacium sp. These molecular tools will be useful for identification and investigation of the ecology of anisakid nematodes in China and elsewhere.