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Multi-view subspace clustering methods have been very popular among all the multi-view clustering approaches. Overall, in the subspace clustering methods, self-expressive representation of data points gives a coefficient matrix. In multi-view approaches coefficient matrices of all views are utilized to achieve one coefficient matrix that gives a clustering of points. In the previous proposed methods, to determine clusters, the focus was often on the sparsity among different clusters. However, the sparsity may cause that data points of the same clusters does not have strong connections, i.e. some points in the same cluster may not be connected that causes a cluster to be a union of two components and it causes the increase of over-segmentation. To address this problem, we apply drop out technique on columns for all views for several times. In each step, some columns are dropped out and just the remaining points have role in the self-representative combinations of points. Then we consider all self-expressive representations, simultaneously. This method improves the intra-clusters connectivity as well as some other criteria. Our method is evaluated on some real world multi-views data set for confirming its performance. The results depict that the method works well and the proposed algorithm has excellent connectivity. Moreover, some other criteria, which have been improved, are compared with some other contemporary approaches. [ABSTRACT FROM AUTHOR]

Background: Radiotherapy is a common treatment for head-and-neck malignancies and causes complications such as oral candidiasis and the change of oral Candida species from albicans to nonalbicans. Voriconazole has acceptable antifungal effect. The aim of this study was to determine and compare the antifungal effect of nystatin with voriconazole on these species. Materials and Methods: The samples used in this in vitro study were identified by polymerase chain reaction-restriction fragment length polymorphism from patients before and 2 weeks after head-and-neck radiotherapy in Seyed Al-Shohada Hospital. The antifungal effect of nystatin and voriconazole was determined by microdilution method and measurement of the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration, and the results were analyzed by Mann--Whitney analysis. Results: The results showed that all species before and after radiotherapy showed 100% sensitivity to nystatin. Prior to radiotherapy, 57.1% of albicans species isolated were in the sensitive range (MIC ≤1) and 42.9% were in the dose-dependent range (MIC = 2) to voriconazole. After radiotherapy, 58.3% of albicans species were in the sensitive range and 41.7% of these species were in the dose-dependent range to voriconazole. Conclusion: The results of the present study showed that before radiotherapy, all species were sensitive to nystatin, while a percentage of albicans and nonalbicans were resistant to voriconazole. In the 2nd week of radiotherapy similar to prior to radiotherapy, all species isolated from patients were sensitive to nystatin, while a percentage of albicans and nonalbicans were resistant to voriconazole. [ABSTRACT FROM AUTHOR]

Background: Patients undergoing head-and-neck radiotherapy are susceptible to Candida colonization and infection. This study aimed to identify oral Candida species type (ST), colony count (CC), and oropharyngeal candidiasis (OPC) in head-and-neck cancer patients, undergoing radiotherapy, before and 2 weeks after radiation. Materials and Methods: In this quasi-experimental study, head-and-neck cancer patients undergoing radiotherapy (up to 6000 cGy) were recruited. Samples were taken before and 2 weeks after radiation therapy (RT). CC was assigned using Sabouraud dextrose agar culture medium and morphological studies were performed to confirm OPC. For identification, polymerase chain reaction-restriction fragment length polymorphism was performed. Data were analyzed using Chi-square-test and kappa coefficient. P < 0.05 was considered statistically significant. Results: Twenty-one of 33 patients were Candida positive. The detected fungal species included Candida albicans (60%), Candida tropicalis (22%), Candida glabrata (9%), and other species (9%). Following RT, OPC and CC changed significantly (P = 0.003 and P = 0.001, respectively), whereas ST did not significantly change (P = 0.081). Two new species (Candida krusei and Candida parapsilosis) were detected after the intervention. The OPC, CC, and ST changes after RT were not significantly related to malignancy site or radiation dose (P > 0.05). Conclusion: The present study showed that OPC, CC, and ST were not related to the malignancy site. Following RT, OPC and CC changed significantly, while ST showed no significant change. The radiation dose and malignancy site had no effects on the OPC, CC, or ST alterations following RT. [ABSTRACT FROM AUTHOR]

Introduction: The quality of root canal treatment depends on the sealing ability of root canal obturation materials. Sealers help create an impenetrable seal. This study aimed to compare the sealing ability of AH Plus and Sure-Seal Root sealers by the fluid filtration technique. Methods: This in-vitro study evaluated 80 extracted human mandibular second premolars. After initial preparation, the teeth were randomly divided into two experimental groups (n=35) and positive and negative control groups (n=5). The experimental groups were obturated with AH Plus sealer and Sure-Seal Root sealer. The AH Plus and the Sure-Seal Root groups were obturated with the lateral condensation technique and the single-cone technique, respectively. Apical leakage was assessed at two intervals of 1 week and 3 months, evaluated by the fluid filtration technique, and compared between the two groups using Student's t-test. Results: No significant differences were observed between the two groups in 7 days. However, after 90 days, the AH Plus group exhibited significantly less leakage than the Sure-Seal Root group. The microleakage of AH Plus decreased over time (P<0.05). Conclusion: In this study, AH Plus exhibited significantly better sealing ability than Sure-Seal Root in the long term. [ABSTRACT FROM AUTHOR]

Spectral clustering has become very popular in recent years, due to the simplicity of its implementation and good performance in clustering non-convex data. Constructing a similarity graph based on an appropriate distance measure for modeling the local neighborhood relations among data samples is crucial for achieving an acceptable performance in spectral clustering. In this paper, we propose a fuzzy spectral clustering algorithm for poorly separated data with arbitrary shapes. Distinguishing poorly separated clusters is a challenging issue since a border point of a cluster may be more similar to the border points of the adjacent cluster than to the points in its own cluster. We propose a local mean-based distance measure which helps in separating points in cluster borders. The distance between a pair of points, in the proposed distance measure, is defined as the distance between the mean of their k nearest neighbors. We also propose a new transitive-based method for computing the membership degrees of points to clusters. Our evaluation results on both artificial and real data show that both the proposed local mean-based distance measure and the proposed membership computation method have significant impacts in obtaining performance improvement over the existing methods. [ABSTRACT FROM AUTHOR]

Let x,y ∈ Rn, we say x is ut-Toeplitz weak majorized by y (written as x ...T y) if there exists an upper triangular substochastic Toeplitz matrix A such that x = Ay. In this paper, we characterize all linear functions that strongly preserve ...T on Rn. [ABSTRACT FROM AUTHOR]

In this paper the relation between the weak subdifferentials and the directional derivatives, as well as optimality conditions for nonconvex optimization problems in reexive Banach spaces, are investigated. It partly generalizes several related results obtained for finite dimensional spaces. [ABSTRACT FROM AUTHOR]

Background: Head-and-neck radiotherapy can change oral Candida species and cause candidiasis resistance to common antifungals by making the changes to the oral cavity environment. Voriconazole is a synthetic azole with extensive antifungal activity. The current study aimed at comparing the antifungal activity of fluconazole and voriconazole on Candida species isolated from the oral cavity of patients undergoing head-and-neck radiotherapy. Materials and Methods: The present in vitro study was performed on samples isolated from patients undergoing head-and-neck radiotherapy, before and during radiotherapy. After the identification of the species, the antifungal effect of fluconazole and voriconazole was determined by the microdilution method, and the minimum inhibitory concentration (MIC), the minimum fungicidal concentration, and the antifungal susceptibility of the isolated strains were also measured. The data were analyzed by the Chi-squared and then two-sided Fisher's exact tests. P < 0.05 was considered statistically significant. Results: The study findings showed no significant difference in the susceptibility of Candida albicans to voriconazole and fluconazole before and during radiotherapy. Before radiotherapy, both voriconazole and fluconazole had similar effects on Candida tropicalis, but after radiotherapy, voriconazole was less effective. However, both before and during radiotherapy, fluconazole had a greater antifungal effect than voriconazole on Candida glabrata strains. The MICs of voriconazole and fluconazole for both Candida parapsilosis and Candida krusei isolates were within the susceptible or dose-dependent range. Conclusion: The current study results showed that voriconazole was not more effective than fluconazole in the treatment of oral candidiasis in patients undergoing head-and-neck radiotherapy. [ABSTRACT FROM AUTHOR]

One of the interesting Laser-Plasma phenomena, when the laser power is high and ultra intense, is the generation of large amplitude plasma waves (Wakefield) and electron acceleration. An intense electromagnetic laser pulse can create plasma oscillations through the action of the nonlinear pondermotive force. electrons trapped in the wake can be accelerated to high energies, more than 1 TW. Of the wide variety of methods for generating a regular electric field in plasmas with strong laser radiation, the most attractive one at the present time is the scheme of the Laser Wake Field Accelerator (LWFA). In this method, a strong Langmuir wave is excited in the plasma. In such a wave, electrons are trapped and can acquire relativistic energies, accelerated to high energies. In this paper the PIC simulation of wakefield generation and electron acceleration in an underdense plasma with a short ultra intense laser pulse is discussed. 2D electromagnetic PIC code is written by FORTRAN 90, are developed, and the propagation of different electromagnetic waves in vacuum and plasma is shown. Next, the accuracy of implementation of 2D electromagnetic code is verified, making it relativistic and simulating the generating of wakefield and electron acceleration in an underdense plasma. It is shown that when a symmetric electromagnetic pulse passes through the plasma, the longitudinal field generated in plasma, at the back of the pulse, is weaker than the one due to an asymmetric electromagnetic pulse, and thus the electrons acquire less energy. About the asymmetric pulse, when front part of the pulse has smaller time rise than the back part of the pulse, a stronger wakefield generates, in plasma, at the back of the pulse, and consequently the electrons acquire more energy. In an inverse case, when the rise time of the back part of the pulse is bigger in comparison with that of the back part, a weaker wakefield generates and this leads to the fact that the electrons acquire less energy. [ABSTRACT FROM AUTHOR]