Search

In China, rural doctors (RDs) perform crucial health care missions. However, they have received less attention than their colleagues in urban public hospitals. In this specific group, a severe challenge occurs in sync with a high turnover rate and deficient job satisfaction. This study aims to systematically summarize and evaluate the influencing factors of job satisfaction and turnover intention among Chinese rural doctors. Seven databases, including PubMed, EMBASE, and China National Knowledge Infrastructure (CNKI), were systematically retrieved, and several experts were consulted to acquire holistic publications in this domain. A total of 20 full-text papers and 22,721 samples were included. In addition, 53 influencing factors were evaluated, of which 38 factors may play a significant role. Based on Herzberg's two-factor theory, together with China's cultural tradition and national conditions, we classified these influencing factors into sociodemographic characteristic factors (n=13), incentive factors (n=18), and health care factors (n=22). Meanwhile, we discussed and analyzed the influencing factors of turnover intention and job satisfaction in detail and put forward corresponding measures and suggestions for the government. We are confident that this research provides a holistic perspective to systematically evaluate the factors influencing the job satisfaction and intention to leave of Chinese rural doctors. Importantly, we hypothesize that the illumination of cases among Chinese rural physicians applies to other countries or regions, which has significant implications for the reformation of the medical system by governments or decision-makers worldwide.

This article examines the politico-scientific mechanism, which leads nations to declare an epidemic or a pandemic finished, irrespective of the actual epidemiological situation at a given time. A historical comparison is made with the famous behavior of Emperor Justinian I (482-565 CE) during the plague pandemic named after him (part of the first plague pandemic). Finally, a reference to the importance of the multidisciplinary study of the history of medicine and the intersection between pandemics and wars is made.

This paper investigates the biochemical oxygen demand (BOD) and the pH level along Jelok River, Kajang, Selangor, Malaysia. The BOD and pH level are of major interest as microbial activity. Five water sampling locations along the river have been selected. To test the pH level of each water sample, a pH meter was used. To test the BOD of each water sample, the 5-days BOD test was conducted. Using the collected data, the Pearson’s correlation coefficient between the pH and BOD was calculated. The computed Pearson correlation coefficient is -0.67988, indicating that pH does affect BOD of the water, specifically for this river. In addition, it demonstrates that when pH value increases, BOD of the water will decrease. The results show that water pH was quite stable, range between 7.05 to 7.65, while BOD fluctuates wildly, range between 1.4 to 4.3 mg/L. According to the BOD value, the high BOD value was found along the bridge at Changkat Road with 4.3 mg/L, and the lowest was found to be the one at Shell Petrol Station along Semenyih Road with BOD value of 1.4 mg/L. From the findings, public and authority shall be alert of the water performance and actions are necessary to preserve the water quality along this river. In addition, it is recommended to compare the water quality parameters among few rivers in future studies.

Uncertainty quantification has always been an important topic in model reduction and simulation of complex systems. In this aspect, global sensitivity analysis (GSA) methods such as Fourier amplitude sensitivity test (FAST) are well recognized as effective algorithms. Recently, some data-based metamodeler such as Random Forest (RF) also developed their own variable importance selection solutions for parameters with perturbations. This paper proposes a visual comparison of these two uncertainty quantification methods, using datasets retrieved from vibroacoustic models. Their results have a lot in common and are capable to explain many results. The remarkable agreement between methods under fundamentally different definitions can potentially improve their compatibility in various occasions.

To investigate the diagnostic performance and usefulness of texture analysis in differentiating angiomyolipoma (AML) without visible fat from clear cell renal cell carcinoma (ccRCC) on four-phase contrast-enhanced computed tomography (CECT).Seventeen patients with AML without visible fat and 50 patients with ccRCC of size ≤4.5 cm who had also undergone preoperative four-phase CECT were included in this study. The histogram, grey-level co-occurrence matrix (GLCM), and grey-level run length matrix (GLRLM) were evaluated. Sequential feature selection (SFS) and support vector machine (SVM) classifier with leave-one-out cross validation were used.Using the SFS and SVM classifiers, five texture features were selected; mean (unenhanced), standard deviation (unenhanced and excretory), cluster prominence (nephrographic), and long-run high grey-level emphasis (corticomedullary). Diagnostic performance of the five selected texture features for all CT phases was as follows: 82% sensitivity, 76% specificity, 85% accuracy, and 85 area under the receiver operating characteristic curve (AUC). In the subgroup analysis, the AUCs of each phase were significantly0.5 (p0.05). In the pairwise comparison of AUCs between four phases, there were no significant differences between the four phases except the unenhanced and corticomedullary phases (p=0.015), i.e., the unenhanced phase showed slightly higher AUC than the corticomedullary phase.Texture analysis of small renal masses (≤4.5 cm) on four-phase CECT can accurately differentiate AML without visible fat from ccRCC and showed good diagnostic performance for both the unenhanced and enhanced phases.

Fast-ramping magnets will be used in the Booster Ring (BRing) of the High-Intensity Heavy Ion Accelerator Facility (HIAF), which is proposed by the Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS). The dipole magnet will provide the field quality from the injection field of 0.0496 T up to the maximum value of 1.5786 T, with the maximum ramping rate of 12 T/s. The ramping magnetic field induces eddy currents that give rise to eddy loss and large force on the beam pipe, field delay and sextupole field appear to affect the field quality provided by the BRing dipole. An in-detail understanding of these effects is an essential aspect of the design. Based on the finite-element analysis, a simplified model by use uniform background magnetic field was used to the transient simulations, eddy current and the forces on the pipe at different times on the beam pipe were performed. This paper presents the results obtained for the eddy loss and magnetic field delay for different wall thicknesses. Then, mechanical design details are presented, and also stress distribution, the deformation in the beam pipe. The analysis results revealed that the eddy current and thus the field delay and eddy current-induced Lorentz force scales linearly with the derivative of the magnetic field and the thickness of the pipe. The power losses that cause heating of the pipe is linear with the square of the derivative of the magnetic field and the thickness of the pipe.

Space Environment Simulation and Research Infrastructure (SESRI) is a new national research infrastructure under construction at Harbin Institute of Technology (HIT) in China. Its 300-MeV proton and heavy ion accelerator is a major radiation source, and a compact synchrotron has been designed with a circumference of less than 44 m. The synchrotron dipoles are essential components of the accelerator, and they have been designed and tested carefully to meet the stringent physical requirements. The measured transverse field homogeneity is less than 2 × 10-4 from 0.2 T to 1.4 T and roughly agrees with the simulated results. With a modified linear programming algorithm, the integral magnetic field uniformity within 0.2–1.1 T is optimised from 6 × 10-4 to 1.5 × 10-4, and the corresponding multi-pole field-component errors are greatly reduced. By shortening the pole ends, the reproducibility of integral field among six magnets at 0.2 T is less than 3 × 10-4. In addition, the transient effect of the magnetic field is also evaluated and tested. Through analysis of the transient effect and structural strength, low-carbon steel and stainless steel are selected for the side plates and end plates, respectively. According to the transient measurement results, the feedforward compensation can be implemented to produce a more accurate current waveform. On 1 January 2022, the beam was successfully accumulated with the preset current waveform, and the beam intensity met the design requirements.

Introduction Apart from the psychiatric symptoms, cognitive deficits are also the core symptoms of schizophrenia. Brain network control theory provided information on the role of a specific brain region in the cognitive control process, helping understand the neural mechanism of cognitive impairment in schizophrenia. Objectives To characterize the control properties of functional brain network in first-episode untreated patients with schizophrenia and the relationships between controllability and psychiatric symptoms, as well as exploring the predictive value of controllability in differentiating patients from healthy controls (HCs). Methods Average and modal controllability of brain networks were calculated and compared between 133 first-episode untreated patients with schizophrenia and 135 HCs. The associations between controllability and clinical symptoms were evaluated using sparse canonical correlation analysis. Support vector machine (SVM) and SVM-recursive feature elimination combined with the controllability were performed to establish the individual prediction model. Results Compared to HCs, the patients with schizophrenia showed increased average controllability and decreased modal controllability in dorsal anterior cingulate cortex (dACC). Brain controllability predominantly in somatomotor, default mode, and visual networks was associated with the positive symptomatology of schizophrenia. The established model could identify patients with an accuracy of 0.68. Furthermore, the most discriminative features were located in dACC, medial prefrontal lobe, precuneus and superior temporal gyrus. Conclusions Altered controllability in dACC may play a critical role in the neuropathological mechanisms of cognitive deficit in schizophrenia, which could drive the brain function to different states to cope with varied cognitive tasks. As symptom-related biomarkers, controllability could be also beneficial to individual prediction in schizophrenia. Disclosure No significant relationships.

Introduction There is a growing consensus on brain networks that it is not immutable but rather a dynamic complex system for adapting environment. The neuroimaging research studying how brain regions work collaboratively with dynamic methods had demonstrated its effectiveness in revealing the neural mechanisms of schizophrenia. Objectives To investigate altered dynamic brain functional topology in first-episode untreated schizophrenia patients (SZs) and establish classification models to find objective brain imaging biomarkers. Methods Resting-state-functional magnetic resonance data for SZs and matched healthy controls were obtained(Table1). Power-264-template was used to extract nodes and sliding-window approach was carried out to establish functional connectivity matrices. Functional topology was assessed by eigenvector centrality(EC) and node efficiency and its time-fluctuating was evaluated with coefficient of variation(CV). Group differences of dynamic topology and correlation analysis between Positive and Negative Syndrome Scale(PANSS) scores and topology indices showing group differences, which also were used in establishing classification models, was examed. Results The CV of node efficiency in angular and paracingulate gyrus was larger in SZs. There are 13 nodes assigned into several brain networks displaying altered CV of EC between groups(Figure1.A). Fluctuation of EC of the node in DMN, which was lower in SZs, showed negative correlation with PANSS total scores(Figure1.B). Dynamic functional topology of above nodes was used to train classification models and demonstrated 80% and 71% accuracy for support vector classification(SVC) and random forest(RF), respectively(Figure2). Conclusions Dynamic functional topology illustrated a capability in identifying SZs. Aberrated dynamics of DMN relevant to severity of patient’s symptoms could reveal the reason why it contributed to classification. Disclosure No significant relationships.

BackgroundGlioblastoma multiforme (GBM) is a type of high-grade brain tumor known for its proliferative, invasive property, and low survival rate. Recently, with the advancement in therapeutics for tumors such as targeted therapy, individual cancer-specific biomarkers could be recognized as targets for curative purposes. This study identified six differentially expressed genes that have shown significant implications in clinical field, including FPR2, VEGFA, SERPINA1, SOX2, PBK, and ITGB3. FPR2 was of the same protein family with FPR1, and the latter has been repeatedly reported to promote motility and invasiveness of multiple tumor forms.MethodsThe gene expression profiling of 40 GBM samples and five normal samples from the TCGA database were comprehensively analyzed. The differentially expressed genes (DEGs) were identified using R package and screened by enrichment analysis and examination of protein–protein interaction networks, in order to further explore the functions of DEGs with the highest association with clinical traits and to find hub genes. A qRT-PCR and Western blots were conducted to verify the results of this study.ResultsOur investigation showed that FPR2, VEGFA, SERPINA1, SOX2, PBK, and ITGB3 were significantly up-regulated in GBM primary tumor compared to the control group. Functional enrichment analysis of the DEGs demonstrated that biological functions related to immune systems, cell division and cell cycle were significantly increased, which were closely related to tumor progression and development. Downstream construction of PPI network analysis indicated that FPR2 was a hub gene involved in high level of interaction with CR3 and VEGFA, which played a key role in inflammatory pathways and cellular dysfunction.ConclusionFPR2, VEGFA, SERPINA1, SOX2, PBK, and ITGB3 were significantly over-expressed in primary tumor samples of GBM patients and were involved in cellular functions and pathways contributing to tumor progression. Out of these six pivotal genes, we intensively focused on FPR2, and our analysis and experimental data both suggested its efficacy as a potential biomarker, serving as an alternative immunotherapeutic target for glioblastoma multiforme.

The High-Intensity Heavy Ion Accelerator Facility (HIAF), proposed by the Institute of Modern Physics, Chinese Academy of Sciences (IMP), is being designed to provide primary and radioactive intense beams for nuclear and related research. As an important part of HIAF, the Booster Ring (BRing) is a fast ramping synchrotron and is used to obtain high intensity (238U35+, 1 × 1011 ppp) and high energy (0.835 GeV/u) heavy-ion beam. Moreover, the beam rigidity of the Booster Ring varies widely from 1 Tm to 34 Tm. These require the dipole of Booster Ring to have a large-good field region, a high magnetic field homogeneity, and a wide range of magnetic field variation from 0.047 T to 1.58 T. Aiming at the properties of the dipole magnet, we adopt some new methods to improve magnetic field precision and optimize efficiency. Double symmetrical air holes in the magnet pole are used to guarantee the magnetic field homogeneity under a wide magnetic field range. At the same time, the linear programming algorithm is adopted to optimize the integral magnetic field uniformity of the iron-dominated dipole magnet, which improves the integral magnetic field precision and optimization efficiency. So far, the prototype dipole magnet has been fabricated and tested. Through magnetic field optimization, measurement, and secondary trimming, the measurement results satisfy the physical requirements.

SYNOPSIS We present an optimal oxygen-blowing system with expert rules to improve the efficiency of refining low-carbon ferrochrome. A nonlinear model based on mass transfer theory, the principles of heat transfer, and the principles of high-temperature chemical reactions for refining low-carbon ferrochrome are established. The model is mainly used to control the oxygen supply rate during argon-oxygen top-bottom double-blown refining, thereby controlling the refining temperature and reducing the carbon content. Twenty production tests using a 5 t argon-oxygen refining furnace demonstrate the effectiveness of the system and reliability of the nonlinear model. A comparison of the model data with the experimental data shows that although the model fails to predict the silicon content in the final refined product, it can predict the contents of the main components at the refining end-point and the refining temperature accurately. Keywords: prediction model, end-point control, mass transfer theory, expert rules.

A control chart is typically examined based on the overall performance. This is crucial, as it will influence the final decision on the selection of a control chart. For this reason, the application of average run length (ARL) has been identified as the standard performance metric. In order to calculate ARL, practitioners must determine the size of the process shift in advance. Nevertheless, in practice, the process shift size cannot be predetermined, as practitioners may not have the requisite information associated with the process. Hence, in this work, the expected average run length (EARL) is employed as a performance metric for the unknown shift size in a process. This work evaluates the performance of a memory-type control chart, i.e. exponentially weighted moving average median (EWMA median) chart, with respect to ARL and EARL. The results indicate that, as long as the deterministic shift size is within the range of the process shift size, the chart’s performance is nearly the same, regardless of the use of the optimal pair based on minimizing ARL or EARL.

Purpose This study was conducted to investigate the feasibility and clinical potential of using the 3D printing technology (3DPT) versus typical strategy (thin-layer CT scan) for the treatment of complicated proximal humeral fractures (PHFs) in old people. Methods Sixty-six old patients age ranging from 61 to 76 years with persistent complicated PHFs were randomly assigned to two groups as per the controlled randomization table (34 cases in the test group and 32 cases in the control group). In the test group, 3DPT was applied to build the 3D facture model of a patient, according to the data acquired from the thin-layer CT scan and subsequently processed with Mimics software. This helped to confirm the diagnosis, design the individual operation plan, simulate the surgical procedures and perform the surgery as plan. In the control group, only thin-layer CT scan was applied for the design of the operation plan prior to the surgery. Here, parameters including surgery duration, blood loss volume during surgery, the number of fluoroscopy, time to union were statistically analyzed for two groups after the operation. The screw lengths designed before the surgery and measured during the surgery were compared. Results The 3D PHF model generated using 3DPT was able to provide the visual display and omni-directional observation of the direction and severity of the fracture dislocation, which facilitated preoperative diagnosis, operation planning and design, data measurement, preselection of internal fixator and surgical outcome simulation. According to the follow-up ranging from 12∼28 months for the 66 patients, the results showed no significant difference in time to union between the two groups ( P > 0.05). Apart from that, less surgery duration, less blood loss during surgery, less number of fluoroscopy can be observed compared with the control group ( P Conclusions In this study, 3DPT showed great clinical feasibility of the treatment of complicated PHFs. The 3D-print PHF model had the ability to clearly display the fracture and thus was useful to determine the fracture classification and the magnitude of fracture injury. It benefited surgeons to gain a better understanding of complicated PHFs, design a most suitable operation plan prior to surgery and facilitate the doctor-patient communication. This therefore enabled the reduction of intraoperative injury and the optimization of surgical outcomes.

Cervical cancer is one of the most prevalent malignancies in women worldwide. Therefore, the investigation about the molecular pathogenesis and related therapy targets of cervical cancer is an emergency. The objective of the present study is to investigate the effects of valproic acid (VPA), a histone deacetylase inhibitor, on the angiogenesis of cervical cancer. The effects and mechanisms of VPA on in vitro angiogenesis and vascular endothelial growth factor (VEGF) expression of human cervical cancer HeLa and SiHa cells were investigated. Our present study reveals that 1 mM VPA can significantly inhibit the in vitro angiogenic potential and VEGF expression of human cervical cancer HeLa and SiHa cells. Further, the transcription and protein levels of hypoxia inducible factor-1α (HIF-1α), and not HIF-1β, are significantly inhibited in VPA-treated cervical cancer cells. Over expression of HIF-1α can obviously reverse VPA-induced VEGF down regulation. VPA-treatment decreases the activation of Akt and ERK1/2 in both HeLa and SiHa cells in a time-dependent manner. The inhibitor of Akt (LY 294002) or ERK1/2 (PD98059) can inhibit VEGF alone and cooperatively reinforce the suppression effects of VPA on HIF-1α and VEGF expression. Collectively, our data reveal that the inhibition of PI3K/Akt and ERK1/2 signals are involved in VPA-induced HIF-1α and VEGF suppression of cervical cancer cells.

［摘要］

Aim To evaluate the outcome of arthroscopy treatment using high-strength line in the treatment of tibial avulsion fracture of posterior cruciate ligament. Methods Both the avulsed bone block and the tibia bone bed were refreshed. The procedure was completed with the assistance of PCL director drill guide. The reduction and fixation using high-strength line were used to fix the avulsed bone by from posterior middle portal. Rehabilitation began early postoperatively. Results From January 2010 to June 2012, a total of 18 arthroscopically treated cases of PCL tibial avulsion fracture were retrospectively evaluated. Reduction of the avulsion fragment was obtained in all cases. 16 cases were followed up for 7–30 months (average 13.6), and 2 cases were out of follow-up. In the 16 followed patients, flexion and extension were back to normal within 6 weeks, and return to normal walk in 12 weeks. The bone healing was good without any vascular or nerve complications. All the patients regained the preinjury activity level. The mean score (and standard deviation) increased from 38.9 ± 4.9 points to 95.2 ± 3.8 points with the system of Lysholm, from 57.1 ± 10.3 points to 94.3 ± 4.4 points with the system of IKDC. Post-test displacement of KT3000 declined from 3.6 ± 0.39 to 1.1 ± 0.27 mm. Conclusion Arthroscopic vertical fixation by high-strength line is a simple, safe, reliable, and micro-invasive treatment to PCL tibial avulsion fracture. It is a kind of real all arthroscopic technique, and good for early postoperative rehabilitation. The total stability of the knee could be gained, and the second operation to remove the internal fixation is avoided.

Thyroid cancer is a very common form of endocrine system malignancy. To date, the molecular mechanism underlying thyroid cancer remains poorly understood. Studies of oncocytic tumors have led to a hypothesis which proposes that defects in oxidative phosphorylation (OX- PHOS) may result in a compensatory increase in mitochondrial replication and gene expression. As a result, mitochondrial DNA (mtDNA) mutation analysis has become a useful tool to explore the molecular basis of this disease. Among these mutations, mitochondrial transfer RNAs (mttRNAs) are the hot spots for pathogenic mutations associated with thyroid cancer. However, due to its high mutation rate, the role of mt-tRNA variants in thyroid cancer is still controversial. To address this problem, in this study, we reassessed seven reported mt-tRNA variants: tRNAAsp G7521A, tRNAArg T10411C and T10463C, tRNALeu(CUN) A12308G, tRNAIle G4292C and C4312T, and tRNAAla T5655C, in clinical manifestations of thyroid cancer. We first performed the phylogenetic conservation analysis for these variants; moreover, we used a bioinformatic tool to compare the minimum free energy (G) of mt-tRNA with and without mutations. Most strikingly, none of these variants caused the significant change of the G between the wild-type and the mutant form, suggesting that they may not play an important roles in thyroid cancer. In addition, we screened the frequency of the “pathogenic” A12308G alternation in 300 patients with thyroid cancer and 200 healthy controls. We found that there were five patients and three control subjects carrying this variant. It seemed that the A12308G variant may be a common polymorphism in the human population. Taken together, our study indicated that variants in mt-tRNA genes may not play active roles in patients with thyroid cancer.

The SUS304 stainless steel is widely used in many industries, and the prediction and detection of fracture tendency in these stainless steel applications are very important for their safety and serviceability. The ductile fracture is caused by micro damage and its accumulation, whose mechanism can be described by the micro void nucleation, growth and final extension to failure. The nucleation, growth and extension of the micro voids are related with the movement of the dislocations. In this paper, the optic microscope, X-ray diffraction and scanning electron microscope were used to observe the changes of the sample during uniaxial tensile tests, and analyse the relationship between micro void and dislocation density, and finally establish a dislocation density-strain model. This model provides a new idea for non-destructive testing, which can be applied to the early identification of fracture tendency.

Sirtuin type 1 (SIRT1) gene plays an important role in the regulation of female reproduction, and we set out to determine if SIRT1 affects steroidogenesis. In this study, granulosa cells isolated from bovine ovaries were cultured and treated with resveratrol or nicotinamide, a SIRT1 activator or inhibitor, respectively. The mRNA and protein levels of SIRT1 of cultured granulosa cells were investigated by quantitative real-time RT-PCR and Western blot, and then the extent of cellular apoptosis was measured by FACS assay. The amounts of estradiol and progesterone in cultured media were measured by radioimmunoassay, and mRNA and protein levels of Steroidogenic Factor 1 (SF-1) were also investigated. We demonstrated that resveratrol exhibited a dose-dependent induction of SIRT1 expression, associated with late apoptosis in granulosa cells, while nicotinamide decreased SIRT1 expression with no effect on apoptosis. We observed the estradiol levels and SF-1 expression decreased while progesterone level increased after the treatment of resveratrol, but the opposite results were observed in the treatment of nicotinamide. In conclusion, SIRT1 affected apoptosis, steroidogenesis and the related gene expression in granulosa cells, which may provide new insight into the treatment of follicular and/or luteal phase deficiency.

The effects of three different feeding systems on beef cattle production performance, rumen fermentation, and rumen digesta particle structure were investigated by using 18 Limousin (steers) with a similar body weight (575±10 kg) in a 80-d experiment. The animals were equally and randomly divided into three treatment groups, namely, total mixed ration group (cattle fed TMR), SI1 group (cattle fed concentrate firstly then roughage), and SI2 group (cattle fed roughage firstly then concentrate). The results showed that the average daily gain was significantly higher in cattle receiving TMR than in those receiving SI1 and SI2 (p

Mitochondrial DNA mutations have been found to play important roles in carcinogenesis. The most common G10398A mutation, a non-conservative amino acid substitution from Thr to Ala, seems to be involved in the tumorigenesis of breast cancer. Results from studies concerning this mutation remain inconclusive. In the current study, we first took clinical and molecular datasets from case-control studies to determine the association between the G10398A mutation and breast cancer. We further used the Phylotree to determine the haplogroups of this mutation. The frequencies of this mutation in 500 unrelated healthy controls were also screened. We found that this mutation is very common in the human population, and may be a polymorph.

Ultrasound Computer Tomography (USCT) is a promising new imaging system for breast cancer diagnosis. An essential step before further processing is to remove the water background from the reconstructed images. In this paper we present a fully-automated image segmentation method based on three-dimensional active contours. The active contour method is extended by applying gradient vector flow and encoding the USCT aperture characteristics as additional weighting terms. A surface detection algorithm based on a ray model is developed to initialize the active contour, which is iteratively deformed to capture the breast outline in USCT reflection images. The evaluation with synthetic data showed that the method is able to cope with noisy images, and is not influenced by the position of the breast and the presence of scattering objects within the breast. The proposed method was applied to 14 in-vivo images resulting in an average surface deviation from a manual segmentation of 2.7 mm. We conclude that automated segmentation of USCT reflection images is feasible and produces results comparable to a manual segmentation. By applying the proposed method, reproducible segmentation results can be obtained without manual interaction by an expert.

Aim To identify magnetic resonance imaging (MRI) features for differentiating hepatocellular carcinoma (HCC) from intrahepatic cholangiocarcinoma (IHCC) and summarise their diagnostic accuracy. Materials and methods PubMed and EMBASE were searched for studies that employed MRI features to differentiate HCC from IHCC. Overlapping descriptors used to denote the same imaging finding in different studies were subsumed under a single feature. The pooled diagnostic accuracies, including the diagnostic odds ratios (DORs) and 95% confidence intervals (CIs) of the identified features, were calculated using a bivariate random-effects model. Results In total, 1,370 patients with HCC and 687 patients with IHCC in 14 studies were included. Fifty-two descriptors were subsumed under 15 MRI features. Of these, 11 features were informative for differentiating HCC from IHCC. The five MRI features favouring HCC were capsule, arterial diffuse enhancement, portal venous washout, conventional washout, and intralesional fat; the six MRI features favouring IHCC were surface retraction, arterial rim enhancement, progressive enhancement, target appearance on diffusion-weighted and hepatobiliary phase (HBP) images, and bile duct dilatation. These features tended to show high specificity, but low sensitivity. Useful MRI features with high DORs (>20) were capsule (34; 95% CI, 5–215) and intralesional fat (23; 4–85) for HCC and arterial rim enhancement (31; 6–160), progressive enhancement (24; 8–73), and target appearance on HBP images (29; 3–261) for IHCC. Conclusion Eleven informative MRI features for differentiating HCC from IHCC were identified. These features will assist in the accurate diagnosis of these diseases and in disease outcome prediction.

The vapour–liquid two-phase flow in the low-pressure cylinder of a 1000 MW nuclear steam turbine has been investigated. Firstly, a comparative study of the flows with equilibrium and non-equilibrium condensation is described. The vapour extraction and moisture removal processes are included in the calculations to simulate the actual operating conditions in the low-pressure cylinder. Differences in the thermodynamic expansion lines, and in the distributions of wetness and degree of reaction, for equilibrium and non-equilibrium flow calculations are discussed. Secondly, the deposition of the fog and coarse water droplets in the last stage stator is investigated computationally. An empirical approach, together with the predictions of the non-equilibrium flow calculation, is used to redistribute the spanwise profile of the wetness at inlet to the last stage of the turbine. The movement and deposition of the water droplets are tracked in a Lagrangian frame. The variations of the fog and coarse water deposition rates are obtained in both the spanwise and axial-chordwise directions.

In this study, a miniature bandpass power divider based on capacitive-loaded multicoupled line is proposed, which features equal-ripple insertion loss, return loss and isolation responses. Owing to the employment of capacitive-loaded transmission line resonators, it can achieve very compact size and wide upper stopband. The proposed bandpass power divider can be designed according to the conventional filter synthesis techniques, and is suitable for on-chip implementation. Specifically, a bandpass power divider with a centre frequency f0 of 5.5 GHz, 18.2% fractional bandwidth, and third-order equal-ripple response is designed and implemented using the commercial GaAs pseudomorphic high electron mobility transistor (pHEMT) process. The circuit size without pads is 0.87 mm×0.95 mm, and the electrical size is only 0.057 λg×0.062 λg at f0. The in-band insertion loss is less than 6 dB with a minimum insertion loss of 5.12 dB. The in-band return loss is better than 10 dB, and the isolation is better than 15 dB. In addition, a wide 30-dB upper stopband up to 57 GHz is achieved.

The influence of C, N, O, Mg, Si and co-implants (Mg + Si) ions implantation with fluences in the wide range 10(13)-10(17) cm(-2) on the yellow luminescence (YL) properties of wurtzite GaN has been studied by photoluminescence (PL) spectroscopy. Two types of n-type GaN samples grown by metal-organic chemical vapor deposition method (MOCVD) and labeled as No-1 and No-2 were studied. In their as-grown states, No-1 samples had strong YL, while No-2 samples had weak YL. Results of the frontside and backside PL measurements in one of the as-grown GaN epifilms are also presented. Comparing the intensity of YL between frontside and backside PL spectra, the backside PL spectrum shows the more intense YL intensity. This implies that most of the intrinsic defects giving rise to YL exist mainly near the interface between the epilayer and buffer layer. Our experimental results show that the intensity ratio of YL to near-band-edge UV emission (I-YL/I-UV) decreases gradually by increasing the C implantation fluence from 10(13) to 10(16) cm(-2) for No-1 samples after annealing at 900 degrees C. When the fluence is 10(17) cm(-2), a distinct change of the I-YL/I-UV is observed, which is strongly increased after annealing. For No-2 samples, after annealing the I-YL/I-UV decreases gradually with increase in the C implantation fluence from 10(13) to 10(15) cm(-2). The I-YL/I-UV is gradually increased with increasing C fluence from 10(16) to 10(17) cm(-2) after annealing, while I-YL/I-UV for other ions-implanted GaN samples decreases monotonically with increase in the ions implantation fluences from 10(13) to 10(17) cm(-2) for both No-1 samples and No-2 samples. It is noted that for annealed C-implanted No-2 samples I-YL/I-UV is much higher than that of the as-grown one and other ion-implanted ones. In addition, I-YL/I-UV for the Mg, Si, and co-implants (Mg + Si) implanted No-2 samples with a fluence of 10(13) cm(-2) after being annealed at 900 degrees C is higher than that of the as-grown one. Based on our experimental data and literature results reported previously, the origins of the YL band have been discussed. (C) 2008 Elsevier B.V. All rights reserved.

Balance constraints are important for a background error covariance (BEC) in data assimilation to spread information between different variables and produce balance analysis fields. Using statistical regression, we develop the balance constraint for the BEC of aerosol variables and apply it to a data assimilation and forecasting system for the WRF/Chem model. One-month products from the WRF/Chem model are employed for BEC statistics with the NMC method. The cross-correlations among the original variables are generally high. The highest correlation between elemental carbon and organic carbon without balance constraints is approximately 0.9. However, the correlations for the unbalanced variables are less than 0.2 with the balance constraints. Data assimilation and forecasting experiments for evaluating the impact of balance constraints are performed with the observations of the surface PM2.5 concentrations and speciated concentrations along an aircraft flight track. The speciated increments of the experiment with balance constraints are more coincident than the speciated increments of the experiment without balance constraints, for the observation information can spread across variables by balance constraints in the former experiment. The forecast results of the experiment with balance constraints show significant and durable improvements from the 3rd hour to the 18th hour compared with the forecast results of the experiment without the balance constraints. However, the forecasts of these two experiments are similar during the first 3 h. The results suggest that the balance constraint is significantly positive for the aerosol assimilation and forecasting.