[en] A nonuniform tissue equivalent anthropomorphic phantom of female hip, which was intended for measuring the isodose distributions in intracavitary radio therapy of cervical carcinoma, was developed. It was made of bone and muscle equivalent materials. CT number of normal organs and tissues in pelvis cavity and lower abdomen of the female were measured with CT scanner and compared with those values obtained from home-made phantom under same scan conditions. The electron density effective atomic number, mass density and CT number of equivalent muscle were as essentially same as real muscle. The clinical application of this phantom showed that its construction is reasonable, convenient in use and suitable for measuring isodose distributions for different programs of intracavitary radio therapy of cervical carcinoma

[en] Purpose: To evaluate the response of bony destruction (BD) of the skull base following radiotherapy in nasopharyngeal carcinoma (NPC) and investigate the implications of bony regeneration (BR) on local control and its related factors. Methods and Materials: Ninety patients with NPC with skull base destruction clearly demonstrated on computed tomography (CT) were reviewed. These patients have completed the prescribed treatment and received regular CT follow-up. A total of 338 sets of CT images of the head and neck were reviewed. The tumor response and the appearance of BR in the previous destructive part of the skull base were recorded and analyzed. The tumor response was divided into complete, partial, or no response. BR was defined as recalcification or sclerotic change with partial or complete healing in the previous osteolytic bony defect. Local failure was confirmed either by pathological or merely by imaging studies showing progression of tumor in consecutive radiological pictures. Results: The distribution of specific sites of bony destruction (BD) in these patients included the sphenoid bone (68%), paracavernous sinus area (48%), petrous apex (47%), clivus (44%), pterygoid plates (20%), and others (7%). The CT showed 57 patients (63%) had BR. All were observed within 1 year after treatment. Sixty-two patients (69%) had complete tumor response after treatment. Analyzed by logistic regression method, tumor response after treatment was found to have a statistically significant correlation with BR (p = 0.0004). Most BR (55/57) was demonstrated in patients with complete tumor response. The 3-year actuarial local control rate was 54 % in these patients. The local control was quite different in the comparison of patients with BR versus those with persistent BD (77% vs. 21%, p < 0.0001). Multivariate analysis showed that patients with complete tumor response or with BR on imaging had statistically better local control than those without either of the two findings (p < 0.05). Conclusion: Appearance of BR at previous destructive skull base following radiotherapy for NPC patients could be clearly demonstrated on CT. Bony regeneration significantly correlated with treatment response and local control. Although the underlying significance of BR was unknown, to predict the outcome after treatment, the appearance of BR shown on CT may imply the complete eradication of tumor in this area

[en] His paper investigated the influence of frequency intensity parameters on the controllability of structures with closely-spaced natural frequencies. The perturbation equations were established for a closed-loop system to study the relationship between frequencies, mode damping ratios and perturbation parameters. The calculation results showed that the damping ratios of two modes are decreasing as the decreasing of intensity parameter values of the structure with closely spaced natural frequencies, indicating that the controllability of corresponding modes was losing. The uncertainties in mass and stiffness matrices were also discussed in this paper.

[en] The structures with closely spaced natural frequencies widely exist in civil engineering; however, the judging criterion of the density of closely spaced frequencies is in dispute. This paper suggests a judging criterion for structures with closely spaced natural frequencies based on the analysis on a controlled 2-DOF structure. The analysis results indicate that the optimal control gain of the structure with velocity feedback is dependent on the frequency density parameter of structure and the maximum attainable additional modal damping ratio is 1.72 times of the frequency density parameter when state feedback is applied. Based on a brief review on the previous researches, a judging criterion related the minimum frequency density parameter and the required mode damping ratio was proposed.

[en] Purpose: To report the treatment results and rectal/bladder complications of cervical carcinoma radically treated with high-dose-rate intracavitary brachytherapy (HDR-IC). The current policy of using three-fraction scheme was examined. Methods and Materials: Between November 1987 and August 1990, 173 patients with cervical carcinoma were treated with curative-intent radiation therapy. Whole pelvic irradiation was administered with 10-MV X ray. Dose to the central cervix was 40-44 Gy in 20-22 fractions, following by pelvic wall boost 6-14 Gy in three to seven fractions with central shielding. ⁶⁰Co sources were used for HDR-IC, and 7.2 Gy was given to Point A for three applications, 1-2 weeks apart. Duration of follow-up was 5-7.8 years. Results: Twenty-eight patients (16%) developed central-regional recurrences. Overall 5-year actuarial pelvic control rate was 83%. By stage, 5-year actuarial pelvic control rates were 94%, 87%, and 72% for Stages IB + IIA, IIB + IIIA, and IIIB + IVA, respectively. Thirty-one patients (18%) developed distant metastasis. Overall 5-year actuarial survival rate was 58%. By stage, 5-year actuarial survival rates were 79%, 59%, and 41% for Stages IB + IIA, IIB + IIIA, and IIIB + IVA, respectively. Sixty-six (38%) and 19 patients (11%) developed rectal and bladder complications, respectively. For rectal complication, the overall actuarial rate was 38% at 5 years. By grade, 5-year actuarial rectal complication rates were 24%, 15%, 4%, and 3% for Grades 1-4, respectively. Overall prevalence of rectal complications was 37% and 14% at 2 and 5 years, respectively. Prevalence of low-grade rectal complication (Grades 1 and 2) was dominant at 2 years (30%), but declined to 8% at 5 years. Prevalence of high-grade, severe rectal complication (Grades 3 and 4) remained steady at 2 and 5 years (7% and 6%, respectively). Five-year actuarial bladder complication was 9%. Five-year prevalence of bladder complication was 2%. Conclusion: Using a three-fraction scheme, survival rate appeared comparable with the existing results of the low-dose-rate technique. The incidence of rectal complication with this scheme remained relatively high. The increased part of rectal complication was predominately low grade. This result suggested that therapeutic gain with this scheme may not be good enough to circumvent its biologic disadvantage. Numbers of fractions >3 must be considered in future trials

[en] We used a computer tomography (CT)-assisted three-dimensional (3D) technique to assess dose to the rectum and bladder in intracavitary brachytherapy (ICBT) for patients with cervical cancer, and compared this technique with the conventional method. The results revealed that the difference in dose to the rectal and bladder wall between these two methods were significant. The CT-assisted technique is a feasible method, and it gives different results than the conventional method

[en] The polyethylenimine-functionalized magnetic chitosan nanoparticles (MCN-PEI) are synthesized and characterized by elemental analysis, TEM, FT-IR, XRD, etc. The MCN-PEI exhibits a core-shell structure, and had a saturation magnetization of 18.7 emu/g (which is high enough for fast magnetic separation). The maximum U(VI) sorption capacity for MCN-PEI reaches 134.6 mg/g at pH 5.0 and 298 K. The good-fitting of both sorption kinetics by pseudo-second-order model and sorption isotherms by Langmuir model indicates chemisorption mechanism. The thermodynamic parameters indicate the spontaneous and exothermic nature for U(VI) sorption. Finally, the magnetic nano-sorbents can be efficiently desorbed by acidified EDTA solution for regeneration. (author)

[en] Soil–structure interaction (SSI) plays an important role in overall structural seismic behavior. However, there is a scarcity of experimental studies evaluating the SSI effects on a full bridge including superstructure, pile foundations and site soil. This paper focused on shaking table investigations on the effects of SSI on a super long-span cable-stayed bridge model with pile groups and mixture soil modelled by using uniaxial laminar shear boxes. The cable-stayed bridge model was subjected to a series of earthquake excitations in the longitudinal direction, including white noise and various earthquake waves. The dynamic interactive behavior of the cable-stayed bridge model was explored for various shaking amplitudes and frequency components. Furthermore, the influences of the soil on the system dynamic characteristics were clarified statistically. The test results show that the SSI obviously affects the seismic response of the cable-stayed bridge model in the longitudinal direction, and corresponding accelerations of structural members are amplified. The bridge seismic response may be underestimated and misinterpreted to some extent while the SSI effects are ignored. It is, therefore, suggested that more attentions should be poured into the SSI effects when performing the seismic design of super long-span cable-stayed bridges. Moreover, the SSI effects on the bridge seismic responses decrease with the increase of shaking amplitude, and significantly change as the frequency components of the input motions vary. When evaluating the system damping ratio with the SSI, the system seismic responses may be varied to a certain degree if the soil viscous damping contribution is neglected.

[en] The growth of Mn on a Si(110) surface at room temperature (RT) and 550 °C has been investigated by scanning tunneling spectroscopy (STM) and X-ray photoelectron spectroscopy (XPS). STM observation shows that the growth at 550 °C results in the formation of nanowires (NWs), while that at RT produces only nanoclusters. The Mn 2p XPS spectra unambiguously reveal that the NWs are composed of MnSi_∼1.7 and the nanoclusters are composed of Mn. Curve-fitting analysis of the spectra shows that 64.9% of the NWs were oxidized due to atmospheric exposure during sample transfer, while the Mn nanoclusters were completely oxidized under the same conditions. This fact indicates that the MnSi_∼1.7 NWs have better oxidation resistance than the Mn clusters, which can be attributed to the protection effect of the SiO₂ layer formed on the NWs and the smaller surface to volume ratio of the NWs comparing with the clusters. The binding energy of Mn 2p for the NWs exhibits a negative shift of ∼0.5 eV with respect to the Mn metallic state, which is similar to the silicide state of earlier transition metals Ti and Cr, but different from that of later transition metals Fe and Ni. This negative shift can be attributed to the contribution of Madelung potential.

[en] Highlights: • A rapid screening method for PC-degrading bacteria was devolved. • A bacterial strain capable of degrading PC was isolated from activated sludge. • Various analyses showed PC degradation after the treatment of the bacterial strain. • Catabolites bisphenol A and 4-cumylphenol from PC depolymerization were detected. Bisphenol-A polycarbonate (PC) is a widely used engineering thermoplastic and its release has caused damage to the ecosystem. Microbial degradation of plastic represents a sustainable approach for PC reduction. In this study, a bacterial strain designated Pseudoxanthomonas sp. strain NyZ600 capable of degrading PC was isolated from activated sludge by using diphenyl carbonate as a surrogate substrate. Within a 30-day period of incubating with strain NyZ600, PC films were analyzed with atomic force microscopy, scanning electron microscope, water contact angle, X-ray photoelectron spectroscopy, fourier transform infrared spectroscopy, differential scan calorimeter and thermogravimetric analysis technique. The analyses results indicated that the treated PC films were bio-deteriorated and formed some “corrosion pits” on the PC film surface. In addition, strain NyZ600 performed broad depolymerization of PC indicated by the reduction of Mn from 23.55 to 16.75 kDa and Mw from 45.67 to 31.97 kDa and two degradation products bisphenol A and 4-cumylphenol (the two monomers of PC) were also found, which established that PC were biodegraded by strain NyZ600. Combing all above results, it is clear that the strain NyZ600 can degrade PC which provides a unique example for bacterial degradation of PC and a feasibility for the removal of PC waste.