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肠道菌群与宿主之间存在相互依赖的共生关系，尤其在机体消化吸收、免疫防御和能量代谢过程中至关重要。婴幼儿时期是肠道菌群建立的关键时间窗，易受生理因素（如出生方式、喂养方式）和病理因素（如不良母体环境、不同胎龄及其他因素）的影响，而此阶段菌群定植异常导致的菌群生态紊乱可对机体健康造成深远影响。本文总结婴幼儿肠道菌群定植的影响因素，综述婴幼儿肠道菌群定植异常与代谢性疾病易感之间的关系及其发生机制，并描述婴幼儿肠道菌群的早期干预疗法，为建立基于肠道菌群相关疾病的早期防治策略提供理论依据。.

A new teaching mode with the combination of online teaching and flipped class was designed and implemented in the Stomatological College of Nanjing Medical University based on the National Online Open Courses, the Virtual Interactive Network Teaching Platform and the E-learning Network Teaching Platform. The new online course system of orthodontic education was constructed with several components including the process and outcome assessments, the professional literature and knowledge summary reports and the virtual interactive online training. With the informative and convenient online teaching resources and modes, students' comprehensive abilities of independent learning were improved.南京医科大学口腔医学院以国家级精品在线开放课程和虚拟仿真实验教学项目为依托，结合学校自主研发的E-learning网络教学平台等在线资源，采用在线教学结合翻转课堂的新型教学模式构建口腔正畸学在线课程体系， 将过程性评价和终结性评价贯穿其中，同时融入专业文献在线汇报和知识重点梳理总结，增加了虚拟交互在线实践训练内容。利用丰富便利的在线教学资源和形式，提高学生自主学习的积极性，实现学生综合能力的自我提升。.

The treatment for post-stroke depression (PSD) is mainly based on a therapeutic strategy combining anti-stroke and anti-depressant drugs. In the present study, the therapeutic effect of curcumin on rats with PSD was detected by open field tests and tail suspension tests, as well as the examination of corticosterone and corticotropin-releasing hormone (CRH) levels in the serum and neurotransmitter 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) and dopamine (DA) levels in the hippocampus. Curcumin notably alleviated depression compared to the controls. Furthermore, long noncoding RNA growth arrest-specific transcript 5 (GAS5) enhanced by curcumin contributed to activation of the BDNF/Trkβ signaling pathway to promote the expression of synaptic-related proteins. GAS5 was demonstrated to function as a sponge of miR-10b. GAS5 upregulation by curcumin could reduce miR-10b to compromise the BDNF mRNA levels. Taken together, these results revealed a novel mechanism of curcumin on PSD through the GAS5/miR-10b/BDNF regulatory axis.

Background Nasopharyngeal carcinoma (NPC) is a rare tumor with highly recurrent and lack of effective treatment. Long non- coding RNAs (lncRNAs) have been reported to play roles in various cancers including NPC. Methods In the current study, two cell lines of NPC (CNE-2Z and 5-8F cells) were transfected with short hairpin RNA (shRNA) targeting lncRNA-ENST00000412010 (shlncRNA) or control shRNA (shControl). Cell proliferation, survival, in vitro colony formation, and in vivo xenograft tumor formation were then investigated. Results The study found that cells transfected with shlncRNA grew significantly slower than the cells transfected with shControl as measured on day 5; increased in Annexin V expression; decreased in colony formation; and smaller in xenograft tumor size on day 45. Expression of DNA damage-inducible transcript 3, dual specificity protein phosphatase 5, insulin receptor substrate 1, interleukin-6, and tribbles homolog 3 genes was significantly up-regulated in the cells transfected with shlncRNA, while gene expression of matrix metalloproteinase-7 and cyclin-dependent kinase 4 inhibitor B was significantly down-regulated in the cells transfected with shlncRNA. Immunoblotting assay confirmed DUSP5 protein was significantly increased while proteins of MMP-7 and CDKN2B were significantly lower in the cells lacking lncRNA than that of the control cells. Conclusions These findings suggested that lncRNA-ENST00000412010 plays a role in modulating NPC survival and tumorigenesis through regulating molecules associated with cell cycle and protein phosphatase.

For effective resistance to virus attack and infection, reducing virus transmission chance, it is extremely important for the medical staff and related workers to have their own safe protection. This paper summarizes the development causes, common locations, and prevention ways about the device related pressure injuries on the face resulted from wearing medical-grade protective equipment for a long working time. The paper proposes the nursing strategy for device related pressure injuries and other nursing strategy is proposed to take care efficiently the device related pressure injuries. Meantime, a corresponding nursing strategy is also suggested to deal with the correlative skin diseases during the application of medical-grade protective equipment. These paper aims to provide reference for the prevention of device related pressure injuries and the care of skin-related diseases for clinical working staff, especially to the respectable personnel in front line of fighting against Corona virus disease 2019.为有效抵抗病毒侵袭和感染，降低病毒传播几率，医护人员及相关工作人员做好自身防护工作异常重要。本文总结了面部应用医用级别防护用具过程中，器械相关压力性损伤发生的原因、常见部位、预防方法，提出发生器械相关压力性损伤后的护理策略，同时提出了在应用医用级别防护用具时，发生相关皮肤疾病的护理策略。本文旨在为临床医护人员，特别是为正在抗击新型冠状病毒疫情一线的人员器械相关压力性损伤防护及皮肤相关疾病护理提供借鉴。.

Simulation on the Ohkawa-mechanism-dominated current drive (OKCD) of electron cyclotron (EC) waves is performed using TORAY-GA linear code, and the results are compared with those calculated by CQL3D quasi-linear code. It is found that the radial location of the OKCD profile is almost identical between the linear and the quasi-linear calculations. However, there are significant differences in the calculation of the total driven current I e c and the peak value of the driven current profile j e c p e a k between the two models. The I e c calculated by the CQL3D code is at least 1.4 times larger than the results from the TORAY-GA code. For the calculation of j e c p e a k , the results from CQL3D are at least 1.6 times larger than that calculated by TORAY-GA. With increasing electron temperature, the two models further enlarge the total driven current scaling factor F I and the peak driven current density scaling factor F j . This is mainly because the collision operator in TORAY-GA code adopts a high-speed model and does not retain the first-order Legendre expansion term for momentum conservation of electron self-collision. The quasi-linear effect does not have a significant influence on the total driven current of OKCD when the EC power level does not meet P r f MW m − 3 n e 10 19 m − 3 > 0.5. Therefore, in practical engineering, the TORAY-GA code can be used to calculate OKCD quickly and accurately by multiplying with appropriate scaling factors. The effect of momentum conservation is very important for OKCD and on-axis EC current drive (ECCD), but this effect is not important for off-axis ECCD. The results from this study show that the effects of electron trapping and the collision between resonant passing electrons and trapped electrons are responsible for the decrease in off-axis ECCD efficiency.

The nonlinear evolution of the m/n = 2/1 double tearing mode (DTM) is investigated by the toroidal resistive magnetohydrodynamic code CLT. It is found that the m/n = 2/1 DTM can lead to either a core pressure crash or an off-axis pressure crash. Unlike the core pressure crash, the plasma pressure at the magnetic axis remains almost unchanged during the off-axis pressure crash. The pressure crash only occurs in the annular region during the off-axis crash, and the on-axis plasma pressure slowly reduces after the crash, which is consistent with TFTR observations. A series of simulations are carried out to investigate the influence of the radial position of the inner resonant surface r 1, the magnetic shear at the inner resonance surface, and the spatial separation between the two resonant surfaces on nonlinear behaviors of DTMs. We find that r 1 plays a dominant role in the nonlinear DTM behaviors. It is more likely for the DTM to lead to the core pressure crash with a smaller r 1. It is also found that the magnetic shear at the inner resonant surface and the spatial separation between the two resonant surfaces can also largely influence the nonlinear evolution of the DTM. A simple theoretical formula of the transition criterion between the two pressure crashes is proposed, which agrees well with the simulation results.

To investigate the biological role of micro-ribonucleic acid (miR)-29a in non-small-cell lung cancer (NSCLC).55 cases of NSCLC tissue specimens and paired normal lung tissue specimens collected in the Department II of Oncology, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine from July 2012 to April 2015 were randomly included. The fluorescent quantitative polymerase chain reaction, Western blotting, and immunohistochemistry were performed to detect the expression levels of miR-29a and metastasis suppressor 1 (MTSS1). Pearson correlation analysis was utilized to investigate the relationship between miR-29a expression and MTSS1 expression in NSCLC tissues, and the Kaplan-Meier survival curves were constructed to analyze the association of miR-29a expression with the survival time of NSCLC patients. A54 proliferation and invasion abilities were measured by means of plate clone formation assay, and transwell assay after the miR-29a was suppressed by miRNA inhibitor. Luciferase assay was used to detect the target gene of miR-29a.In NSCLC tissues, the miR-29a expression level was higher than that in normal lung tissues (p0.05), while the expression level of MTSS1 protein was remarkably lower than that in normal lung tissues (p0.05). The median survival time of the patients was 15.1 months in high miR-29a expression group and 18.3 months in low miR-29a expression group (p0.05). The miR-29a expression was negatively correlated with the expression level of MTSS1 protein in NSCLC tissues (r=-0.762, p0.05). Luciferase results suggest that miR-29a binds to the promoter region of MTSS1 and inhibits its transcription level. The expression of MTSS1 protein was up-regulated notably after miR-29a knockdown by an inhibitor. It was revealed in the results of transwell assay and plate clone formation assay that the proliferative and invasive capacity of A549 cells was significantly decreased after knockdown of miR-29a.The transcribed miR-29a down-regulates the protein level of MTSS1, suppressor of tumor proliferation and invasion, thereby promoting the proliferative and invasive capacity of NSCLC cells. Both miR-29a and MTSS1 are expected to become potential therapeutic targets for NSCLC.

Betatrophin is a recently identified protein that has been shown to be associated with lipid metabolism and insulin resistance. This study aimed to measure serum betatrophin concentrations in patients with type 2 diabetes (T2DM) and evaluate the association of betatrophin with diabetic retinopthy (DR). Serum betatrophin concentrations were compared between (1) gender-, age- and body mass index-matched T2DM patients with (n=17) or without (n=33) DR; (2) gender-, age-, and body mass index-matched healthy subjects (n=31), newly-diagnosed T2DM patients before treatment (n=24), and T2DM patients under antidiabetic treatment (n=35). Serum betatrophin concentrations were determined by the enzyme-linked immunosorbent assay. Multivariate logistic regression was performed to assess the association between betatrophin concentration and DR. Serum betatrophin concentration was significantly associated with DR in T2DM patients under treatment (Odds Ratio 2.01; 95% Confidence Interval 1.12-3.60; p=0.019). Betatrophin concentrations were significantly increased in treated T2DM patients compared to the healthy subjects (4.17±0.60 vs. 0.54±0.07 ng/ml; p0.001). Serum betatrophin concentrations are increased in T2DM patients under antidiabetic treatment and positively associated with diabetic retinopathy.

A new synergy mechanism between Ohkawa current drive (OKCD) of electron cyclotron (EC) waves and lower hybrid current drive (LHCD) is discovered and discussed. And the methodology to achieve this synergy effect is also introduced. Improvement of OKCD efficiency can be achieved up to a factor of ~ 2.5 in far off-axis radial region (\r{ho} > 0.6) of tokamak plasmas. Making EC wave heating the electrons of co-Ip direction and LH wave heating the electrons of counter-Ip direction, the mechanism of this new synergy effect comes from the results of electron trapping and detrapping processes. The OKCD makes the low speed barely passing electrons to be trapped (trapping process), the LHCD pulls some of the high speed barely trapped electrons out of the trapped region in velocity space (detrapping process) and accelerates the detrapped electrons to a higher speed., 9 pages, 9 figures

Purpose Stereotactic radiosurgery (SRS) is an effective alternative to microsurgical resection or embolization for definitive treatment of arteriovenous malformations (AVMs). Digital subtraction angiography (DSA) is the gold standard for pretreatment diagnosis and characterization of vascular anatomy, but requires rigid frame (skull) immobilization when used in combination with SRS. With the advent of advanced proton and image-guided photon delivery systems, SRS treatment is increasingly migrating to frameless platforms, which are incompatible with frame-based DSA. Without DSA as the primary image, target definition may be less than optimal, in some cases precluding the ability to treat with a frameless system. This article reports a novel solution. Methods and Materials Fiducial markers are implanted into the patient’s skull before angiography. Angiography is performed according to the standard clinical protocol, but, in contrast to the previous practice, without the rigid frame. Separate images of a specially designed localizer box are subsequently obtained. A target volume projected on DSA can be transferred to the localizer system in three dimensions, and in turn be transferred to multiple CT slices using the implanted fiducials. Combined with other imaging modalities, this “virtual frame” approach yields a highly precise treatment plan that can be delivered by frameless SRS technologies. Results Phantom measurements for point and volume targets have been performed. The overall uncertainty of placing a point target to CT is 0.4 mm. For volume targets, deviation of the transformed contour from the target CT image is within 0.6 mm. The algorithm and software are robust. The method has been applied clinically, with reliable results. Conclusions A novel and reproducible method for frameless SRS of AVMs has been developed that enables the use of DSA without the requirement for rigid immobilization. Multiple pairs of DSA can be used for better conformality. Further improvement, including using nonimplanted fiducials, is potentially feasible.

Shear flows induced by the nonlinear evolution of double tearing modes are studied numerically using Hall magnetohydrodynamics simulations in a slab geometry. The Hall effect is shown to plays an important role when the thickness of current sheets decrease and falls in the range of ion inertia length d i . Effective shear flows in the magnetic islands are generated during the process of magnetic reconnection and disappear finally. The induced toroidal velocity are shown to be more sensitive than the induced poloidal velocities in the Hall dominant systems. Moreover, the temporal evolution of the shear flows in the Tokamak resonant surface is studied and discussed.

The coupling asymmetry characteristics of an ion cyclotron resonance heating (ICRH) antenna consisting of two poloidal aligned straps are studied for a JET-type tokamak. The model used combines a three-dimensional (3-D) planar, cold-plasma, single pass antenna-plasma coupling code with any phase difference between the current straps, which takes into account the feeders' current and phase difference effects. The result shows that the asymmetry of radiated energy in poloidal direction can be controlled through changing the phase difference of the antenna straps, and when the phase difference equals to π, the asymmetry tends to become most pronounced (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Purpose: To compare the effect of respiration-induced motion on delivered dose (the interplay effect) for different treatment techniques under realistic clinical conditions. Methods: A flexible resin tumor model was created using rapid prototyping techniques based on a computed tomography (CT) image of an actual tumor. Twenty micro-MOSFETs were inserted into the tumor model and the tumor model was inserted into an anthropomorphic breathing phantom. Phantom motion was programed using the motion trajectory of an actual patient. A four-dimensional CT image was obtained and several treatment plans were created using different treatment techniques and planning systems: Conformal (Eclipse), step-and-shoot intensity-modulated radiation therapy (IMRT) (Pinnacle), step-and-shoot IMRT (XiO), dynamic IMRT (Eclipse), complex dynamic IMRT (Eclipse), hybrid IMRT [60% conformal, 40% dynamic IMRT (Eclipse)], volume-modulated arc therapy (VMAT) [single-arc (Eclipse)], VMAT [double-arc (Eclipse)], and complex VMAT (Eclipse). The complex plans were created by artificially pushing the optimizer to give complex multileaf collimator sequences. Each IMRT field was irradiated five times and each VMAT field was irradiated ten times, with each irradiation starting at a random point in the respiratory cycle. The effect of fractionation was calculated by randomly summing the measured doses. The maximum deviation for each measurement point per fraction and the more » probability that 95% of the model tumor had dose deviations less than 2% and 5% were calculated as a function of the number of fractions. Tumor control probabilities for each treatment plan were calculated and compared. Results: After five fractions, measured dose deviations were less than 2% for more than 95% of measurement points within the tumor model for all plans, except the complex dynamic IMRT, step-and-shoot IMRT (XiO), complex VMAT, and single-arc VMAT plans. Reducing the dose rate of the complex IMRT plans from 600 to 200 MU/min reduced the dose deviations to less than 2%. Dose deviations were less than 5% after five fractions for all plans, except the complex single-arc VMAT plan. Conclusions: Rapid prototyping techniques can be used to create realistic tumor models. For most treatment techniques, the dose deviations averaged out after several fractions. Treatments with unusually complicated multileaf collimator sequences had larger dose deviations. For IMRT treat-ments, dose deviations can be reduced by reducing the dose rate. For VMAT treatments, using two arcs instead of one is effective for reducing dose deviations. « less

Localized current drive by electron cyclotron (EC) waves is of significant importance in the outer half region of tokamak plasmas. Using the coupled GENRAY/CQL3D suite codes, a systematic comparative study between Ohkawa current drive (OKCD) and electron cyclotron current drive (ECCD) is performed. The results show that OKCD has more advantages than ECCD for far off-axis localized current drive in tokamaks with large inverse aspect ratios, while ECCD is more efficient than OKCD in tokamaks with low inverse aspect ratios. The results of local current driving on the q = 2 rational surface show that both OKCD and ECCD are effective for control of the m = 2/n = 1 tearing mode or neoclassical tearing mode (NTM). It seems that efficient Ohkawa current can be driven in a specific far off-axis radial position as long as the local inverse aspect ratio is large enough. The effect of collisionality imposes a significant impact on OKCD and results in reduction of the net current driven by unit EC power. The dimensionless current drive efficiency of OKCD increases with increasing electron beta βe in a medium range. The results further confirm that OKCD can be a valuable alternative localized current drive method to replace ECCD in large inverse aspect ratio tokamaks or in the radial position where the local inverse aspect ratio is large enough.

Control of the current profile is a crucial issue for improved confinement and the inhibition of instability in advanced tokamak operation. Using typical discharge data for the Experimental Advanced Superconducting Tokamak, numerical simulations of driven-current profile control in mode conversion current drive (MCCD) in the ion cyclotron range of frequencies were performed employing a full-wave method and Ehst–Karney efficiency formula. Results indicate that the driven current profile in MCCD can be effectively modified by shifting the mode conversion layer. The peak of the driven current can be located at an aimed position in the normalized minor radius range (−0.60≤r/a≤0) by changing the radiofrequency and the minority-ion concentration. The efficiency of the off-axis MCCD can reach 233 kA/MW through optimization, and the mode converted ion cyclotron wave plays an important role in such scenarios. The effects of electron temperature and plasma density on the driven current profile are also investigated.Control of the current profile is a crucial issue for improved confinement and the inhibition of instability in advanced tokamak operation. Using typical discharge data for the Experimental Advanced Superconducting Tokamak, numerical simulations of driven-current profile control in mode conversion current drive (MCCD) in the ion cyclotron range of frequencies were performed employing a full-wave method and Ehst–Karney efficiency formula. Results indicate that the driven current profile in MCCD can be effectively modified by shifting the mode conversion layer. The peak of the driven current can be located at an aimed position in the normalized minor radius range (−0.60≤r/a≤0) by changing the radiofrequency and the minority-ion concentration. The efficiency of the off-axis MCCD can reach 233 kA/MW through optimization, and the mode converted ion cyclotron wave plays an important role in such scenarios. The effects of electron temperature and plasma density on the driven current profile are also investigated.

Purpose There are no data on how complication rates after accelerated partial-breast irradiation delivered by three-dimensional conformal radiotherapy are affected by treatment technique. We therefore examined the risk of pneumonitis in relation to lung dose-volume parameters. Patients and Methods Our prospective dose-escalation trial enrolled 198 treated patients from 2003 to 2007. Patients received 32 or 36 Gy in 4-Gy fractions, given twice daily: 29 (14%) were treated with pure photons; 149 (77%) with mixed photons and electrons; and 20 (10%) with protons. Results There were four cases of pneumonitis at 4, 4, 7, and 9 months after treatment. All were in the 36-Gy cohort and were treated with pure photons. The risk of pneumonitis for the two cohorts combined was: 17% (four of 24) for an ipsilateral lung volume (ILV) receiving 20 Gy or higher (ILV, 20 Gy) of 3% or higher (P = .0002 for comparison to ILV 20 Gy < 3%, Fisher's exact test); 20% (four of 20) for an ILV 10 Gy of 10% or higher (P = .0001); and 15% (four of 26) for an ILV 5 Gy of 20% or higher (P = .0002). Conclusion The risk of pneumonitis appeared related to the ILV treated. This volume can be reduced by using mixed photons and electron when possible. We recommend that the ILV 20 Gy should be lower than 3%, the ILV 10 Gy lower than 10%, and the ILV 5 Gy lower than 20% when purely coplanar techniques are used.

For short-range high-LET radiation therapy, the biological effects are strongly affected by the heterogeneity of the specific energy distribution delivered to tumor cells. Three-dimensional information at the cellular level is ideal for this type of study, but it is extremely difficult to obtain. In this paper, a novel microdosimetry analysis, which obtains the specific energy distribution directly from the morphological information in individual autoradiographic sections, is applied to in vivo human glioblastoma multiforme and normal brain tissue in boron neutron capture therapy. Specific energy distributions were obtained for both specimens, and they are consistent with a uniform boron microdistribution. We also used a biophysical model for cell survival analysis based on the specific energy and were able to bridge it with the model based on the corresponding macroscopic parameter (dose) using existing experimental data. The survival constant for the microscopic model was determined; cell survival curves were predicted for uniform and non-uniform source distributions, i.e., sources and cell nuclei bound together totally or only partially. The results indicate that the behavior of the survival curve can vary widely, which may have important clinical implications.

Purpose Respiratory motion presents a significant challenge in stereotactic body radiosurgery. Respiratory tracking that follows the translational movement of the internal fiducials minimizes the uncertainties in dose delivery. However, the effect of deformation, defined as any changes in the body and organs relative to the center of fiducials, remains unanswered. This study investigated this problem and a possible solution. Methods and Materials Dose delivery using a robotic respiratory-tracking system was studied with clinical data. Each treatment plan was designed with the computed tomography scan in the end-expiration phase. The planned beams were applied to the computed tomography scan in end-inspiration following the shift of the fiducials. The dose coverage was compared with the initial plan, and the uncertainty due to the deformation was estimated. A necessary margin from the clinical target volume to the planning target volume was determined to account for this and other sources of uncertainty. Results We studied 12 lung and 5 upper abdomen lesions. Our results demonstrated that for lung patients with properly implanted fiducials a 3-mm margin is required to compensate for the deformation and a 5-mm margin is required to compensate for all uncertainties. Our results for the upper abdomen tumors were still preliminary but indicated a similar result, although a larger margin might be required. Conclusion The effect of body deformation was studied. We found that adequate dose coverage for lung tumors can be ensured with proper fiducial placement and a 5-mm planning target volume margin. This approach is more practical and effective than a recent proposal to combine four-dimensional planning with respiratory tracking.

The objective of this investigation was to map QTL controlling oil, protein, and starch concentrations in maize grain and to evaluate their genetic effects. The mapping population included 298 F2:3 family lines containing Beijing high-oil (BHO) maize germplasm. F2 individuals were genotyped with 183 SSR markers to construct a genetic linkage map, which spanned 1,605.7 cM, with an average interval of 8.77 cM. Oil, protein, and starch concentrations in grain among F2:3 families were measured by near-infrared (NIR) analyzer. Using QTL Cartographer, we mapped six QTL associated with oil in grain, six associated with protein, and five associated with starch concentrations. The proportion of phenotypic variation explained by single QTL ranged from 4.34 to 13.13% for oil, from 5.19 to 6.66% for protein, and from 4.14 to 7.85% for starch concentrations. QTL for oil, protein, or starch concentrations were often detected in identical intervals and the direction of their effects were consistent with the sign of their phenotypic correlation. They were considered as common QTL for chemical compositions in maize grain. In this study, we identified three QTL for oil in grain, two QTL for protein, and three QTL for starch concentrations, which were on identical or similar chromosomal locations to those previously mapped with Illinois high-oil (IHO) maize germplasm. These suggests that more diverse germplasm should be necessary to detect additional QTL and to discover more favorable alleles for chemical composition of maize grain.

For short range high linear energy transfer (LET) radiation therapy the biological effects are strongly affected by the heterogeneity of the specific energy (z) distribution delivered to tumour cells. Three-dimensional (3-D) dosimetry information at the cellular level is required for this study. An ideal approach would be the reconstruction of the cell and the radiation source microdistribution from sequential autoradiographic sections, which is, however, not a practical solution. In this paper, a novel microdosimetry analysis method, which obtains the specific energy (z) distribution directly from the morphological information in individual autoradiographic sections, is applied to human glioblastoma multifore (GBM) and normal brain tissue specimens in boron neutron capture therapy. The results are consistent with Monte Carlo simulation and demonstrate a uniform radiation source distribution in both GBM and normal brain tissues. We also hypothesise a biophysical model based on specific energy for survival analysis. The specific energy distributions to cell nuclei were calculated with a uniform radiation source distribution. By combining this microdosimetric analysis with measured cell survival data at the low dose region, a cell survival curve at high doses is predicted, which is consistent with the commonly used simple exponential curve model for high LET radiation.

A Phase I/II clinical trial of neutron capture therapy (NCT) was conducted at Harvard–MIT using a fission converter epithermal neutron beam. This epithermal neutron beam has nearly ideal performance characteristics (high intensity and purity) and is well-suited for clinical use. Six glioblastoma multiforme (GBM) patients were treated with NCT by infusion of the tumor-selective amino acid boronophenylalanine-fructose (BPA-F) at a dose of 14.0 g/m 2 body surface area over 90 min followed by irradiation with epithermal neutrons. Treatments were planned using NCTPlan and an accelerated version of the Monte Carlo radiation transport code MCNP 4B. Treatments were delivered in two fractions with two or three fields. Field order was reversed between fractions to equalize the average blood boron concentration between fields. The initial dose in the dose escalation study was 7.0 RBE Gy, prescribed as the mean dose to the whole brain volume. This prescription dose was increased by 10% to 7.7 RBE Gy in the second cohort of patients. A pharmacokinetic model was used to predict the blood boron concentration for determination of the required beam monitor units with good accuracy; differences between prescribed and delivered doses were 1.5% or less. Estimates of average tumor doses ranged from 33.7 to 83.4 RBE Gy (median 57.8 RBE Gy), a substantial improvement over our previous trial where the median value of the average tumor dose was 25.8 RBE Gy.

A flexible technique for positioning patients in fixed orientation radiation fields such as those used in neutron capture therapy (NCT) has been developed. The positioning technique employs reference points marked on the patient in combination with a 3D digitizer to determine the beam entry point and a template fitted to the patient's head is used to determine the proper beam orientation. A coordinate transformation between the CT image data and reference points on the patient determined by a least squares algorithm based on singular value decomposition is used to map the beam entry point from the planning system onto the patient. The technique was validated in a phantom study where the mean error in entry point placement was 1.3 mm. Five glioblastoma multiforme patients have been treated with NCT using this positioning technique.

The effect of helical driven current on the m = 2/n = 1 tearing mode is studied numerically in a cylindrical geometry using the method of reduced magneto-hydro-dynamic simulation. The results show that the local persistent helical current drive from the beginning time can be applied to control the tearing modes, and will cause a rebound effect called flip instability when the driven current reaches a certain value. The current intensity threshold value for the occurrence of flip instability is about 0.00087I0. The method of controlling the development of tearing mode with comparative economy is given. If the local helical driven current is discontinuous, the magnetic island can be controlled within a certain range, and then, the tearing modes stop growing; thus, the flip instability can be avoided. We also find that the flip instability will become impatient with delay injection of the driven current because the high order harmonics have been developed in the original O-point. The tearing mode instability...

Fast wave in the ion-cyclotron resonance frequency (ICRF) range is a promising candidate for non-inductive current drive (CD), which is essential for long pulse and high performance operation of tokamaks. A numerical study on the ICRF fast wave current drive (FWCD) and mode-conversion current drive (MCCD) in the Experimental Advanced Superconducting Tokamak (EAST) is carried out by means of the coupled full wave and Ehst-Karney parameterization methods. The results show that FWCD efficiency is notable in two frequency regimes, i.e., f ≥ 85 MHz and f = 50–65 MHz, where ion cyclotron absorption is effectively avoided, and the maximum on-axis driven current per unit power can reach 120 kA/MW. The sensitivity of the CD efficiency to the minority ion concentration is confirmed, owing to fast wave mode conversion, and the peak MCCD efficiency is reached for 22% minority-ion concentration. The effects of the wave-launch position and the toroidal wavenumber on the efficiency of current drive are also investigated.

The Cyberknife delivers frameless image-guided stereotactic radiosurgery to intracranial and extracranial tumors. We report our use of Cyberknife radiosurgery on a medullary plasmacytoma in the clivus extending into the foramen magnum. No acute toxicity was seen during or within 24 hours of treatment, and the subject had a complete and durable radiographic response on MRI 12+ months after treatment. To our knowledge, this is a first case of successful Cyberknife radiosurgery of a medullary plasmacytoma.

Non‐water solid phantoms are often used in the determination of absorbed dose to water for electron beams. Protocols have been established and widely accepted. In these procedures, several assumptions in addition to the Spencer–Attix conditions are required, and several correction factors are needed. A direct approach, in which the conversion is carried out in a single step using a modified Spencer–Attix formula, is studied in this paper. The approach is consistent with the protocols for water phantom, and the conversion factors can be calculated using Monte Carlo simulation. The behavior of the conversion factors is described by comparing the results from the AAPM protocol and experiment data for three electron energies (6, 12, and 16 MeV). This study demonstrates that for beam calibration at d max, the results from the new approach agree with those from the protocol with a maximum discrepancy of 1% for PMMA and 1.3% for polystyrene. For the depth dose measurement from near the surface to R 80, the agreement is within 1.5% for PMMA, 2.5% for polystyrene, and 2.8% for electron solid water. It also demonstrates that for electron solid water, the new approach provides better agreement with experiment data for the beam calibration at d max.

The effect of toroidal plasma rotation on q = 3 double tearing modes (DTMs) was studied numerically in cylindrical geometry using the method of reduced magnetohydrodynamic simulation. The results indicate that toroidal plasma rotation can reduce the growth rate of DTMs, but the magnitude of toroidal velocity has weak effect, especially without shear. When the shear of toroidal velocity exists, the suppression effect becomes better. Whether the velocity flow has shear or not, the growth rate of DTMs decreases as the magnitude of toroidal velocity increases. With the increase of velocity shear, the DTMs grow slowly. And the suppression effect of toroidal plasma rotation in early growth and transition stage is better, which means that the toroidal plasma rotation can suppress the linear growth of islands. Furthermore, the toroidal plasma rotation can suppress the evolution of poloidal stream. And the toroidal velocity shear on the q = 3 rational surface is more dominant than the magnitude of toroidal velocit...

Rapid economic growth has given rise to a significant increase in ozone precursor emissions in many regions of China, especially in the densely populated North China Plain (NCP) and Yangtze River Delta (YRD). Improved understanding of ozone formation in response to different precursor emissions is imperative to address the highly nonlinear ozone problem and to provide a solid scientific basis for efficient ozone abatement in these regions. A comparative study on ozone photochemical production in summer has thus been carried out in the megacities of Tianjin (NCP) and Shanghai (YRD). Two intensive field campaigns were carried out respectively at an urban and a suburban site of Tianjin, in addition to routine monitoring of trace gases in Shanghai, providing data sets of surface ozone and its precursors including nitrogen oxides (NOx) and various volatile organic compounds (VOCs). Ozone pollution was found to be more severe in Tianjin than in Shanghai during the summer, either based on the frequency or the duration of high ozone events. Such differences might be attributed to the large amount of highly reactive VOC mixture in the Tianjin region. It is found that industry related species like light alkenes were of particular importance in both urban and suburban Tianjin, while in Shanghai aromatics dominate. In general, the ozone problem in Shanghai is on an urban scale. Stringent control policies on local emissions would help reduce the occurrence of high ozone concentrations. By contrast, ozone pollution in Tianjin is a regional problem. Combined efforts to reduce ozone precursor emissions on a regional scale must be undertaken to bring the ozone problem under control.

Prototype miniature dosimeter probes have been designed, built, and characterized employing a small, radiation sensitive metal oxide semiconductor field effect transistor (MOSFET) chip to measure, in vivo, the total accumulated dose and dose rate as a function of time after internal administration of long range beta particle radiolabeled antibodies and in external high energy photon and electron beams. The MOSFET detector is mounted on a long narrow alumina substrate to facilitate electrical connection. The MOSFET, alumina substrate, and lead wires are inserted into a 16 gauge flexineedle, which, in turn, may be inserted into tissue. The radiation dosimeter probe has overall dimensions of 1.6 mm diam and 3.5 cm length. The MOSFET probe signals are read, stored, and analyzed using an automated data collection and analysis system. Initially, we have characterized the probe's response to long range beta particle emission from 90Y sources in solution and to high energy photon and electron beams from linear accelerators. Since the prototype has a finite substrate thickness, the angular dependence has been studied using beta particle emission from a 90Sr source. Temperature dependence and signal drift have been characterized and may be corrected for. Measurements made in spherical volumes containing 90Y with diameters less than the maximum electron range, to simulate anticipated geometries in animal models, agree well with Berger point kernel and EGS4 Monte Carlo calculations. The results from the prototype probes lead to design requirements for detection of shorter range beta particles used in radioimmunotherapy and lower photon energies used in brachytherapy.

Searches for point astrophysical sources of ultra high energy (UHE) gamma rays are plagued by large numbers of background events from isotropic cosmic rays. Some of the methods that have been used to estimate the expected number of background events coming from the direction of a possible source are found to contain biases. Search techniques that avoid this problem are described. There is also a discussion of how to optimize the sensitivity of a search to emission from a point source.

Sampling techniques using randomly distributed points and regular Cartesian grids were compared for the evaluation of volume, dose‐volume histogram, tumorcontrol, and normal tissue complication probabilities in radiation treatments. Particularly, the uncertainties associated with each sampling technique in estimating the dose‐volume histograms for several dose distributions are analyzed in detail. It is found that the estimation of these parameters using sampling points on a regular Cartesian grid is, in general, significantly more efficient than using random points. This finding is different from other published results. The choice of grid size for sampling was analyzed according to the AAPM recommended uncertainty on the dose delivered to the patient. It was concluded that when grid sampling is used, a grid size of 0.5 cm is adequate for most plans to meet the guidelines.

Neutrino-electron elastic scattering was observed with a 15-ton fine-grained tracking calorimeter exposed to electron neutrinos from muon decay at rest. The measured ${\ensuremath{\nu}}_{e}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\nu}}_{e}{e}^{\ensuremath{-}}$ elastic scattering rate of 236\ifmmode\pm\else\textpm\fi{}35 events yields the total elastic scattering cross section $10.0\ifmmode\pm\else\textpm\fi{}1.5(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.9(\mathrm{syst})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}45} \mathrm{c}{\mathrm{m}}^{2}\ifmmode\times\else\texttimes\fi{}[{E}_{\ensuremath{\nu}} (\mathrm{MeV})]$, and a model-independent measurement of the strength of the destructive interference between the charged and neutral currents, $I=\ensuremath{-}1.07\ifmmode\pm\else\textpm\fi{}0.21$, that agrees well with the standard model (SM) prediction $I=\ensuremath{-}1.08$. The agreement between the measured electroweak parameters and SM expectations is used to place limits on neutrino properties, such as neutrino flavor-changing neutral currents and neutrino electromagnetic moments. Limits are placed on the masses of new bosons that interact with leptons: for a neutral tensor boson, ${M}_{T}g105$ GeV; for a neutral (pseudo)scalar boson, ${M}_{P,S}g47$ GeV; for a charged Higgs boson, ${M}_{{\ensuremath{\chi}}^{+}}g87$ GeV; and for a purely left-handed charged (neutral) vector boson, ${M}_{x}g239 (119)$ GeV.

The process of electron emission from {similar to}30 MeV neutrino absorption on carbon, {sup 12}C({nu}{sub {ital e}},{ital e}{sup {minus}}){sup 12}N, has been observed. The flux-weighted total cross section for the exclusive neutrino-induced nuclear transition {sup 12}C({nu}{sub {ital e}},{ital e}{sup {minus}}){sup 12}N(g.s.) is (1.05{plus minus}0.10(stat){plus minus}0.10(syst)){times}10{sup {minus}41} cm{sup 2}. The measured cross section and angular distribution {ital d}{sigma}/{ital d}{Omega} are in agreement with theoretical estimates. The inclusive {nu}{sub {ital e}} {sup 12}C reaction rate, which accounted for the majority of all neutrino interactions observed in this experiment, was determined from a detailed fit of energy and angular distributions for the observed electrons. The inclusive {sup 12}C({nu}{sub {ital e}},{ital e}{sup {minus}}){ital X} cross section is measured to be (1.41{plus minus}0.23(tot)){times}10{sup {minus}41} cm{sup 2}. An upper limit for the sum of the {sup 13}C({nu}{sub {ital e}},{ital e}{sup {minus}}){ital X}+{sup 27}Al({nu}{sub {ital e}},{ital e}{sup {minus}}){ital X} inclusive absorption cross sections is presented.

The CYGNUS extensive air-shower experiment is described. The design criteria, construction and operation details, and performance characteristics are presented. A discussion of the data analysis techniques is given. Finally, several enhancements and improvements in the apparatus are described.

Pseudorabies virus has a class 2 genome in which the S component is found in two orientations relative to the L component. The L component is bracketed by sequences that are partially homologous; it is found mainly in one orientation, but a small proportion is inverted (J. M. DeMarchi, Z. Lu, G. Rall, S. Kuperschmidt, and T. Ben-Porat, J. Virol. 64:4968-4977, 1990). We have ascertained the role of the patchy homologous sequences bracketing the L component in its inversion. A viral mutant, vYa, from which the sequences at the right end of the L component were deleted was constructed. Despite the absence of homologous sequences bracketing the L component in vYa, its L component inverted to an extent similar to that of the L component in the wild-type virus. These results show the following. (i) The low-frequency inversion of the L component of PrV is not mediated by homologous sequences bracketing this component. (ii) Cleavage of concatemeric DNA at the internal junction between the S and L components is responsible for the appearance of the minority of genomes with an inverted L component in populations of pseudorabies virus. (iii) The signals present near or at the end of the S component are sufficient to allow low-frequency cleavage of concatemeric DNA; the sequences at the end of the L component are not essential for cleavage, although they enhance it considerably.