A Formulation of the Porous Medium Equation with Time-Dependent Porosity: A Priori Estimates and Regularity Results

We consider a generalized form of the porous medium equation where the porosity ϕis a function of time t: ϕ=ϕ(x,t): ∂(ϕS)∂t−∇⋅(k(S)∇S)=Q(S).In many works, the porosity ϕis either assumed to be independent of (or to depend very little of) the time variable t. In this work, we want to study the case where it does depend on t(and xas well). For this purpose, we make a change of unknown function V=ϕSin order to obtain a saturation-like (advection-diffusion) equation. A priori estimates and regularity results are established for the new equation based in part on what is known from the saturation equation, when ϕis independent of the time t. These results are then extended to the full saturation equation with time-dependent porosity ϕ=ϕ(x,t). In this analysis, we make explicitly the dependence of the various constants in the estimates on the porosity ϕby the introduced transport vector w, through the change of unknown function. Also we do not assume zero-flux boundary, but we carry the analysis for the case Q≡0.

Vulvectomy: Indications and Results in the General Surgery Department of the Ignace Deen Chu Hospital in Conakry

Introduction: The aim of this study was to report the indications and evaluate the results of vulvectomy in the general surgery department of Ignace Deen Hospital, CHU Conakry. Materials and Methods: This was a retrospective descriptive study, conducted over a period of five (05) years from January 1, 2018 to December 31, 2022, in the general surgery department of Ignace Deen Hospital, CHU Conakry. We included in our study all patient records in whom vulvectomy was performed. Results: We recorded 15 cases of vulvectomy out of 453 perineal surgeries, i.e. 3.31%, with a mean age of 43.56 years and extremes of 35 and 69 years. Vulvar cancer was the most common diagnosis (46.67%), followed by Buschke-Lowenstein (33.33%) and anal canal cancer extending to the vulva (20%). Six patients had undergone biopsy (40%). Vulvectomy with lymph node dissection was performed in only 9 patients (60%), and all surgical specimens were sent to anatomical pathology (100%). Conclusion: Vulvectomy is a surgical technique most often indicated for the treatment of vulvar cancer.

Diagnostic challenges from conflicting results of tests and imaging

Accurate diagnosis is the foundation of clinical care but accurate diagnosis is not easily reached in some cases.In rare instances,even a sophisticated multidisciplinary team at an academic medical center cannot reliably reach an accurate diagnosis after extensive testing and imaging,and has to wait until histological diagnosis or even autopsy results are available.The underlying reason of challenging diagnoses is mostly conflicting data from history,tests,and imaging that point to different diagnoses.In this issue of World Journal of Clinical Cases,Huffaker et al reported such a challenging case of a tricuspid mass in a patient with Li-Fraumeni syndrome.The case by Huffaker et al powerfully illustrates the occasional diagnostic challenges inherent in our current diagnostic approach and the current technology.Clinicians should realize that in rare situations,agnosticism in diagnosis is unavoidable but a treatment has to be initiated so long as the principle of primum non nocere is upheld.

Effect of Types and Orders of Electromagnetic Field Finite Element Meshes on Power Communication Harmonic Parameters Calculation Results of Tubular Hydrogenerators

In generator design field,waveform total harmonic distortion(THD)and telephone harmonic factor(THF)are parameters commonly used to measure the impact of generator no-load voltage harmonics on the power communication quality.Tubular hydrogenerators are considered the optimal generator for exploiting low-head,high-flow hydro resources,and they have seen increasingly widespread application in China's power systems recent years.However,owing to the compact and constrained internal space of such generators,their internal magnetic-field harmonics are pronounced.Therefore,accurate calculation of their THD and THF is crucial during the analysis and design stages to ensure the quality of power communication.Especially in the electromagnetic field finite element modeling analysis of such generators,the type and order of the finite element meshes may have a significant impact on the THD and THF calculation results,which warrants in-depth research.To address this,this study takes a real 34 MW large tubular hydrogenerator as an example,and establishes its electromagnetic field finite element model under no-load conditions.Two types of meshes,five mesh densities,and two mesh orders are analyzed to reveal the effect of electromagnetic field finite element mesh types and orders on the calculation results of THD and THF for such generators.

GoPubMed与Web of Knowledge分析工具Analyze Results的比较研究

GoPubMed是基于本体论的生物医学文献分析工具,它可以对检索到的PubMed文献进行全方位的统计分析,Web of Knowlegde平台的Analyze Results分析功能也可对检索结果进行统计分析。对这2种文献分析工具特点进行对比分析。

ISI Web of Knowledge新增分析工具Results Analysis探讨——BIOSIS Previews检索实践

针对检索结果的信息分析和信息挖掘的分析工具Results Analysis是ISI Web of Knowledge于2004年新增的服务功能。以BIOSIS Previews为检索实例,详细探讨Results Analysis分析工具的使用方法和功能,并提出改进的建议。

ISI Web of Science的Results Analysis功能与使用

详细介绍了美国Web of Science数据库的发展以及该数据库新推出的Results Analysis功能和使用方法。

Long-term results of paclitaxel plus cisplatin with concurrent radiotherapy for loco-regional esophageal squamous cell carcinoma

AIM To evaluate the long-term effectiveness and late toxicities of paclitaxel(PTX) plus cisplatin(DDP) with concurrent radiotherapy for locally advanced esophageal squamous cancer.METHODS Between 2008 and 2011, 76 patients were enrolled in a phase Ⅱ study on the treatment of loco-regionally advanced esophageal cancer with radiotherapy(68.4 Gy/44 fractions or 61.2 Gy/34 fractions) combined with 4-cycle chemotherapy consisting of DDP(25 mg/m^2 per day for 3 d) and PTX(175 mg/m^2 for 3 h). The primary endpoints were overall survival and progression-free survival, and the secondary endpoints were toxicity and the treatment failure pattern.RESULTS A total of 76 patients were enrolled in this study, of whom 63.2% finished the whole regimen. The 5-year survival rates for the per-protocol population and intent-to-treat population were 25.4% and 26.4%, respectively, and the median survival rates were 23.7 mo and 28.5 mo, respectively. Grade 3 or 4 late toxicity was observed in only one patient(heart failure). In log-rank analysis, the pretreatment stage(stage Ⅱ + Ⅲ: 36.1 mo vs stage Ⅳ: 14.9 mo) and the completed cycle(1-3 cycles: 16.1 mo vs 4 cycles: 35.5 mo) were significant prognostic factors(P = 0.037 < 0.05 and P = 0.013 < 0.05).CONCLUSION Radiotherapy combined with chemotherapy consisting of PTX and DDP is a safe and effective definitive treatment for loco-regionally advanced esophageal squamous cancer.

NEW MAGNETOSTRATIGRAPHIC AND SEDIMENTOLOGIC RESULTS FROM TERTIARY SEDIMENTS OF THE HOH XIL BASIN, NORTHERN QINGHAI-TIBET PLATEAU: IMPLICATIONS FOR THE CENOZOIC TECTONIC HISTORY OF THE TIBET PLATEAU

To contribute to the understanding of the ages of large sedimentary basins in northern Tibet, and the Cenozoic tectonic history of Asia in general, we conducted an integrated paleomagnetic and stratigraphic study on the sedimentary sequences of the Hoh Xil basin, north of the Qinghai\|Tibet Plateau. Red sedimentary sections from the Fenghuoshan and Yaxicuo Groups have recorded a pattern of magnetic polarity reversals that correlates well with the known magnetic polarity time scale for the past 56Ma. Reliable magnetostratigraphy for the Fenghuoshan and Yaxicuo Groups suggests that the sediment ages for these two groups are about 56～29Ma and 29～25Ma, respectively.We collected more than 1000 paleomagnetic samples from 335 sites distributed in 3 sections of the Hoh Xil basin. Detailed litholostratigraphic, petrologic, and sedimentologic studies have also been carried out on these sections during the past three field sessions. Magnetic directions in these sites were obtained by progressive alternating\|field and thermal demagnetization experiments. Most samples exhibit two components of magnetization. The lower unblocking temperature component is an overprint resembling the geocentric axial dipole field direction at the sampling locality. The most stable, characteristic remanence (ChRM) appears to be an early chemical remanent magnetization residing mainly in hematite. Curie temperature determinations, acquisition of isothermal remanent magnetization (IRM) and backfield demagnetization of saturation IRM, hysteresis loop parameters, and low\|temperature demagnetization on representative samples all corroborate demagnetization behavior. The positive results of fold and reversal tests indicate that the ChRM is a record of the paleomagnetic field close to the time of formation of these sediments. Further evidence that the magnetization of these sediments was acquired close to their time of deposition is the fact that patterns of magnetic reversals have been identified, which can be matched with the established polarity time scale.

Long-term results of laparoscopic fenestration for patients with congenital liver cysts

BACKGROUND: The feasibility and immediate outcome of laparoscopic fenestration for patients with congenital liver cysts have been generally recognized. The aim of the present study was to assess the long-term results after laparoscopic fenestration. METHODS: A retrospective study was performed on 44 patients with congenital liver cysts who had undergone laparoscopic fenestration between June 1998 and December 2004. Among them, 30 were women and 14 men, aged 57 years on average (range 18-76 years). While 14 patients had solitary cysts, 20 had multiple cysts, and 10 had polycystic liver disease. The results of laparoscopic fenestration, including mortality, morbidity, mean postoperative hospital stay, and recurrences of cysts were evaluated. RESULTS: There was no perioperative death and the morbidity rate was 11% (5/44). All complications were treated conservatively. The mean postoperative hospital stay was 4 days. A mean follow-up of 57 months showed that the rates of cyst recurrence and symptom recurrence were 9% and 4.5%, respectively. CONCLUSION: Laparoscopic fenestration as a feasible and safe treatment procedure for patients with congenital liver cysts can yield very good long-term results.

Deformation field around a thrust fault:A comparison between laboratory results and GPS observations of the 2008 Wenchuan earthquake

On May 12,2008,an Mw7.9 earthquake occurred in Wenchuan County,Sichuan Province,China.Movement of Yingxiu–Beichuan Fault in the Longmenshan Fault Zone was considered to be the main cause of the earthquake.Earthquakes are closely related to fault activities.Therefore,studying the strain distribution and evolution process around active fault zones is important to the understanding of seismic activities.In this study,we conduct laboratory experiments with uniaxial compression applied to marble sheets with intentionally fabricated cracks.The speckle patterns of the rock samples under different loading conditions are recorded in real time by a digital camera.To calculate the deformation fields of the deliberately cracked marble sheets during different stages of the loading processes,the recorded images are processed by the digital image correlation method.The distribution and variation of the displacement and strain are further analyzed in order to understand the strain localization of and observed damage in the experimental fracture zones.Finally,we compare these laboratory results with the GPS-observed coseismic displacements during the 2008 Wenchuan earthquake,to assess the consistency between our laboratory observations and the field observations of the earthquake,but also to suggest how laboratory results can improve thinking about how earthquake patterns do and do not reflect fault patterns.

THREE-DIMENSIONAL INTERACTIONS OF A HALF-PLANE CRACK IN A TRANSVERSELY ISOTROPIC PIEZOELECTRIC SPACE WITH RESULTANT SOURCES

Exact solutions in elementary functions are derived for the stress and electric displacement intensity factors of a half-plane crack in a transversely isotropic piezoelectric space interacting with various resultant sources, including force dipole, electric dipole, moment, force dilatation and rotation. Such force and charge sources may model defects like vacancies, foreign particles and dislocations. The locations and orientations of the stress and charge sources with respect to the crack are arbitrary.

Preliminary results of the High Energetic Particle Package on-board the China Seismo-Electromagnetic Satellite

The high energetic particle package(HEPP) on-board the China Seismo-Electromagnetic Satellite(CSES) was launched on February 2, 2018. This package includes three independent detectors: HEPP-H, HEPP-L, and HEPP-X. HEPP-H and HEPP-L can detect energetic electrons from 100 keV to approximately 50 MeV and protons from 2 MeV to approximately 200 MeV. HEPP-X can measure solar X-rays in the energy range from 1 keV to approximately 20 keV. The objective of the HEPP payload was to provide a survey of energetic particles with high energy, pitch angle, and time resolutions in order to gain new insight into the space radiation environments of the near-Earth system. Particularly, the HEPP can provide new measurements of the magnetic storm related precipitation of electrons in the slot region, and the dynamics of radiation belts. In this paper, the HEPP scientific data sets are described and initial results are provided.The scientific data can show variations in the flux of energetic particles during magnetic storms.

Generalization of Results of Computations and Natural Experiments at Steel Parts Quenching

Complicated changes occur inside the steel parts during quenching process. A three dimensional nonlinear mathematical model for quenching process has been established and the numerical simulation on temperature field, microstructure and stress field has been realized. The alternative technique for the formation of high-strength materials has been developed on the basis of intensification of heat transfer at phase transformations. The technology for the achievement of maximum compressive residual stresses on the hard surface is introduced. It has been shown that there is an optimal depth of hard layer providing the maximum compression stresses on the surface. It has also been established that in the surface hard layer additional strengthening (superstrengthening) of the material is observed. The generalized formula for the determination of the time of reaching maximum compressive stresses on the surface has been proposed.

Prognostic value of site-specific metastases in pancreatic adenocarcinoma: A Surveillance Epidemiology and End Results database analysis

To evaluate the prognostic value of site-specific metastases among patients with metastatic pancreatic carcinoma registered within the Surveillance, Epidemiology and End Results (SEER) database.METHODSSEER database (2010-2013) has been queried through SEER*Stat program to determine the presentation, treatment outcomes and prognostic outcomes of metastatic pancreatic adenocarcinoma according to the site of metastasis. In this study, metastatic pancreatic adenocarcinoma patients were classified according to the site of metastases (liver, lung, bone, brain and distant lymph nodes). We utilized chi-square test to compare the clinicopathological characteristics among different sites of metastases. We used Kaplan-Meier analysis and log-rank testing for survival comparisons. We employed Cox proportional model to perform multivariate analyses of the patient population; and accordingly hazard ratios with corresponding 95%CI were generated. Statistical significance was considered if a two-tailed P value < 0.05 was achieved.RESULTSA total of 13233 patients with stage IV pancreatic cancer and known sites of distant metastases were identified in the period from 2010-2013 and they were included into the current analysis. Patients with isolated distant nodal involvement or lung metastases have better overall and pancreatic cancer-specific survival compared to patients with isolated liver metastases (for overall survival: lung vs liver metastases: P < 0.0001; distant nodal vs liver metastases: P < 0.0001) (for pancreatic cancer-specific survival: lung vs liver metastases: P < 0.0001; distant nodal vs liver metastases: P < 0.0001). Multivariate analysis revealed that age < 65 years, white race, being married, female gender; surgery to the primary tumor and surgery to the metastatic disease were associated with better overall survival and pancreatic cancer-specific survival.CONCLUSIONPancreatic adenocarcinoma patients with isolated liver metastases have worse outcomes compared to patients with isolated lung or distant nodal metastases. Further research is needed to identify the highly selected subset of patients who may benefit from local treatment of the primary tumor and/or metastatic disease.

THREE-DIMENSIONAL INTERACTIONS OF CIRCULAR CRACK IN TRANSVERSELY ISOTROPIC PIEZOELECTRIC SPACE WITH RESULTANT SOURCES

Exact solutions in form of elementary functions were derived for the stress and electric displacement intensity factors of a circular crack in a transversely isotropic piezoelectric space interacting with various stress and charge sources： force dipoles, electric dipoles, moments, force dilatation and rotation. The circular crack includes penny-shaped crack and external circular crack and the locations and orientations of these resultant sources with respect to the crack are arbitrary. Such stress and charge sources may model defects like vacancies, foreign particles, and dislocations. Numerical results are presented at last.

RESEARCH ON OPTIMIZING THE MERGING RESULTS OF MULTIPLE INDEPENDENT RETRIEVAL SYSTEMS BY A DISCRETE PARTICLE SWARM OPTIMIZATION

The result merging for multiple Independent Resource Retrieval Systems (IRRSs), which is a key component in developing a meta-search engine, is a difficult problem that still not effectively solved. Most of the existing result merging methods, usually suffered a great influence from the usefulness weight of different IRRS results and overlap rate among them. In this paper, we proposed a scheme that being capable of coalescing and optimizing a group of existing multi-sources-retrieval merging results effectively by Discrete Particle Swarm Optimization (DPSO). The experimental results show that the DPSO, not only can overall outperform all the other result merging algorithms it employed, but also has better adaptability in application for unnecessarily taking into account different IRRS's usefulness weight and their overlap rate with respect to a concrete query. Compared to other result merging algorithms it employed, the DPSO's recognition precision can increase nearly 24.6%, while the precision standard deviation for different queries can decrease about 68.3%.

Overview of the Latest Scientific Results of China’s Lunar Exploration Program

China’s Chang’E-4 probe successfully landed on 3 January 2019 in Von Kármán crater within the South Pole-Aitken(SPA)basin on the lunar far side.Based on the data acquired by the scientific payloads onboard the lander and the rover,the researchers obtained the related information such as the geologic and tectonic setting of the landing area,compositional characteristics of the landing surface materials,dielectric permittivity and density of the lunar soil.The experiments confirmed the existence of materials dominated by olivine and low-calcium pyroxene in the SPA basin on the lunar far side,which preliminary revealed the geological evolution history of the SPA basin and even that of the early time lunar crust,as well as the tectonic setting and formation mechanism of the materials in the lunar interior.The researchers also investigated the particle radiation,Linear Energy Transaction(LET)spectrum,and so forth on the lunar surface.The low-frequency radio observations were carried out on the lunar far side for the first time as well.This article summarizes the latest scientific results in the past years,focusing on the Chang’E-4 mission.

Long-term results of an anatomically implanted hip arthroplasty with a short stem prosthesis (MiniHip^(TM))

AIM To evaluate the clinical and radiological outcome nineand ten years after short-stemmed, bone preserving and anatomical hip arthroplasty with the MiniHip^(TM) system. METHODS In a prospective study, 186 patients underwent hip arthroplasty with a partial neck preserving short stem(MiniHip^(TM), Corin). Elderly patients were not excluded from this study, thus the mean age at the time of surgery was 59.3 years(range 32 to 82 years). Surgery and the follow-up assessments were performed at two Centers. Up until now, the mean follow-up was 112.5 ± 8.2 mo. The Oxford Hip Score(OHS) and the Hip Dysfunction Osteoarthritis and Outcome Score(HOOS) was assessed pre-and each year after surgery. The clinical follow-up was accompanied by standardized a.p. and axial radiological examinations. Periprosthetic lucencies, hypertrophies within the Gruen zones one to fourteen were assessed. A subsidence of the stem was investigated according to Morray and heterotopic ossifications were assessed according to Brooker.RESULTS The OHS and HOOS improved from 18 ± 3.3 to 46 ± 2.0 and from 30 ± 8.3 to 95 ± 4.6 points, P < 0.001 respectively. There were no differences regarding age, etiology, friction pairings, etc.,(P > 0.05). Two stems were revised due to a symptomatic subsidence four and twelve months postoperatively. Thus, the survivorship for aseptic loosening at nine to ten years was 98.66%. Including one stem revision due to a symptomatic exostosis, bursitis and thigh pain as well as one revision because of a septic stem loosening, the overall survival for the stem with revision for any reason was 97.32%. Besides one asymptomatic patient, radiological signs of a proximal stress-shielding, such as bone resorptions within the proximal Gruen zones, were not noticed. Findings suggesting a distal loading, e.g., bony hypertrophies or bone appositions of more than 2 mm, were also not detected. CONCLUSION Regarding these first long-term results on the MiniHip^(TM), the implant performed exceedingly well with a high rate of survivorship for aseptic loosening. Our radiological results within the Gruen zones support the design rationale of the Minihip to provide a reliable metaphyseal anchoring with the expected proximal, more physiological load transfer. This might minimize or exclude a stress shielding which might be associated with thigh pain, proximal bone loss and an increased risk of aseptic loosening. The MiniHip^(TM) is a reliable partial-neck retaining prosthesis with good a clinical long-term outcome in younger as well as elderly patients.

Gene Knockdown in Human Rhinovirus 1B Using 2′-OMe-modified si RNAs Results in the Reactivation of the Interferon Response

The aim of this study was to investigate the knockdown efficiency of 2＇-O-methylated （2＇-OMe）-modified small interfering RNAs （siRNAs） on human rhinovirus 1B （HRV1B） replication and the interferon response. Thus, 24 2＇-OMe-modified siRNAs were designed to target HRV1B. The RNA levels of HRV1B, Toll-like receptor 3, melanoma differentiation-associated gene 5, retinoic acid inducible gene-I, and interferons were determined in HRV1B-infected HeLa and BEAS-2B epithelial cells transfected with 2＇-OMe-modified siRNAs. The results revealed that all 2＇-OMe-modified siRNAs interfered with the replication of HRVIB in a cell-specific and transfection efficiency-dependent manner. Viral activation of Toll-like receptor 3, melanoma differentiation-associated gene 5, retinoic acid inducible gene-1, and the interferon response was detected. In conclusion, the 2＇-OMe-modified siRNAs used in this study could interfere with HRV1B replication, possibly leading to the reactivation of the interferon response.