Controllable skyrmion chirality in ferroelectrics

Chirality, an intrinsic handedness, is one of the most intriguing fundamental phenomena in nature. Materials composed of chiral molecules find broad applications in areas ranging from nonlinear optics and spintronics to biology and pharmaceuticals. However, chirality is usually an invariable inherent property of a given material that cannot be easily changed at will. Here, we demonstrate that ferroelectric nanodots support skyrmions the chirality of which can be controlled and switched. We devise protocols for realizing control and efficient manipulations of the different types of skyrmions. Our findings open the route for controlled chirality with potential applications in ferroelectric-based information technologies.

[CLINICAL STUDY OF THE STATE OF RESIN-BONDED FIXED PARTIAL DENTURES IN INDIVIDUALS WITH HIGH TEETH ABRASION]

The object of the paper is a clinical assessment of the resin-bonded fixed partial dentures (RBFPD) produced by the indirect method of dental composite resin materials with various reinforcement, in patients with I degree high teeth abrasion. 80 persons with I degree high teeth abrasion and small defects in the lateral part of dental arch with a length of not more than one tooth were examined. For patients of I group, 40 RBFPDs were made of nano dental composite resin and three glass fiber tapes laid horizontally; for patients of II group, 40 RBFPDs made of hardened nano dental composite resin were reinforced with the same tapes laid by the developed method. In 12 months, fractures and fixation disorders of 9 dentures were found in patients from I group (22.5% of the initial quantity), and patients of II group had fixation disorders in 2 dentures (5.0%), and 7 (17.5%) and 32 dentures (80.0%), respectively, had no significant and insignificant disorders. In 24 months, the patients of I group had fractures and fixation disorders of another 7 dentures (22.6% of the number of RBFPDs at a given time), and patients from II group had such disorders in 3 RBFPDs (7.9%), while 3 dentures (7.5% of the initial amount) and 22 RBFPDs (55.0%), respectively, had no disorders. In order to restore the dental integrity with small bounded edentulous teeth in patients with I degree high teeth abrasion, it is possible to use RBFPDs indirect production of which requires the application of hardened nano dental composite resin with reinforcement by means of three glass fiber tapes according to the developed method, which ensures restoration efficiency within 12 and 24 months at the level of 80.0% and 55.0%.

Enhancement of optical and mechanical properties of Si nanopillars by ALD TiO2 coating

The mechanical and optical properties of Si and TiO₂–Si nanopillars (NPl) were investigated.

A phase I trial of DNA vaccination with a plasmid expressing prostate-specific antigen in patients with hormone-refractory prostate cancer

Prostate-specific antigen (PSA) is a serine protease secreted at low levels by normal luminal epithelial cells of the prostate and in significantly higher levels by prostate cancer cells. Therefore, PSA is a potential target for various immunotherapeutical approaches against prostate cancer. DNA vaccination has been investigated as immunotherapy for infectious diseases in patients and for specific treatment of cancer in certain animal models. In animal studies, we have demonstrated that vaccination with plasmid vector pVAX/PSA results in PSA-specific cellular response and protection against tumour challenge. The purpose of the trial was to evaluate the safety, feasibility and biological efficacy of pVAX/PSA vaccine in the clinic. A phase I trial of pVAX/PSA, together with cytokine granulocyte/macrophage-colony stimulating factor (GM-CSF) (Molgramostim) and IL-2 (Aldesleukin) as vaccine adjuvants, was carried out in patients with hormone-refractory prostate cancer. To evaluate the biologically active dose, the vaccine was administered during five cycles in doses of 100, 300 and 900 μg, with three patients in each cohort. Eight patients were evaluable. A PSA-specific cellular immune response, measured by IFN-γ production against recombinant PSA protein, and a rise in anti-PSA IgG were detected in two of three patients after vaccination in the highest dose cohort. A decrease in the slope of PSA was observed in the two patients exhibiting IFN-γ production to PSA. No adverse effects (WHO grade >2) were observed in any dose cohort. We demonstrate that DNA vaccination with a PSA-coding plasmid vector, given with GM-CSF and IL-2 to patients with prostate cancer, is safe and in doses of 900 μg the vaccine can induce cellular and humoral immune responses against PSA protein.

Selective loss of endogenous p21waf1/cip1 induction underlies the G1 checkpoint defect of monomeric p53 proteins

Wild-type p53 protein displays a spectrum of activities including the ability to suppress transformed cell growth to direct apoptotic cell death and to mediate G1 checkpoint in response to cellular DNA damage. Earlier work showed that a self-association defective p53 protein retained transformation suppressor activity in rat embryo fibroblast based assays, but that monomerisation of tumour mutant p53 proteins resulted in loss of dominant transforming activity. In order to acquire a more detailed understanding of the biological consequences attendant on disruption of p53:p53 association we have carried out a study of the wild-type-like activities that are retained by monomeric p53 proteins and which are associated with the suppression of transformation. Here we show that monomeric p53 proteins are G1 checkpoint defective. Although able to stimulate transcription via a p53 DNA binding motif from the p21waf1/cip1 gene promoter in episome based assays these p53 proteins are unable to transactive the chromosomal p21waf1/cip1 gene and are sensitive both to degeneracy of consensus binding site and to half site spacing. Monomeric p53 proteins fail to trigger apoptosis in a BRK cell line transformed with E7 and ras. However, they retain wild type transformation suppressor activity in BRK cell based transformation assays. Our results indicate that p21waf1/cip1 induction and all related p53 dependent G1 checkpoint activities are dispensable for the p53 directed suppression of transformed cell growth, and that such transformation suppression by monomeric p53 proteins may occur in the absence of an apoptotic response.