High-precision Finishing Hard Steel Surfaces Using Cutting, Abrasive and Burnishing Operations

AbstractThis paper presents the technological and functional capabilities of surface textures produced by high-precision cutting, abrasive and ball burnishing operations on hardened steel parts of about 60 HRC hardness. Special focus was placed on surface textures generated by hard turning, belt grinding and ball burnishing operations which are characterized by the Sz roughness parameter of about 1.3μm and distinctly different values of the Sa parameter. Apart from the standard 2D and 3D roughness parameters, the fractal and motif parameters were analyzed

Energy consumption characterization in precision hard machining using CBN cutting tools

In this paper, the contribution of tool wear to the energy balance was determined for precision hard turning using chamfered CBN cutting tools. The tool nose wear VBC and the corresponding changes of component forces Fc, Ff and Fp resulting from tool wear evolution were continuously measured during wear tests. Based on the cutting mechanics, specific cutting and ploughing energies were calculated for a number of tool wear states. In particular, changes of energy balance due to tool wear under variable feed rate, depth of cut and tool nose radius were discussed. A distinction between material removal conditions resulting from precision cutting and grinding at a very low uncut chip thickness is considered. © 2015, The Author(s)

Fertility-sparing treatment of endometrial cancer - is it possible? A case study

Background: Endometrial cancer is the most common gynecological malignant neoplasm, which occurs in the majority of cases postmenopausally. The current standard of treatment is surgical - total hysterectomy.  However, it may also occur in younger patients, who are planning pregnancy and want to choose fertility-sparing treatment. For those patients oral high dose progestin therapy with or without hysteroscopic resection should be proposed. It is usually a good option for women with well-differentiated (G1) cancers. For patients with higher grade (G2, G3) or contraindications to progestins, fertility-sparing treatment of endometrial cancer seems impossible. Case report: We present the case of a 34-year old woman diagnosed gynecologically due to abnormal bleeding from the genital tract. Based on USG, she was diagnosed with endometrial polyp. As a treatment, hysteroscopic resection was performed. In the histopathological evaluation G2 endometrial cancer was diagnosed. The standard approach would be a total hysterectomy, but the patient was interested in fertility-sparing options. Due to contraindications to progestins a total hysteroscopic resection was performed counseling the patient about the risks of a novel approach. Histopathology revealed no residual disease and no other lesions during the first year of observations occurred. Conclusion: Total hysteroscopic resection without further progestin therapy may offer the possibility to treat G2 endometrial cancer despite contraindications to the administration of progestins. Our case report should also encourage further evaluation of fertility-sparing management of endometrial cancer with higher than G1 grade

Structural basis for small molecule targeting of the programmed death ligand 1 (PD-L1)

Targeting the PD-1/PD-L1 immunologic checkpoint with monoclonal antibodies has provided unprecedented results in cancer treatment in the recent years. Development of chemical inhibitors for this pathway lags the antibody development because of insufficient structural information. The first nonpeptidic chemical inhibitors that target the PD-1/PD-L1 interaction have only been recently disclosed by Bristol-Myers Squibb. Here, we show that these small-molecule compounds bind directly to PD-L1 and that they potently block PD-1 binding. Structural studies reveal a dimeric protein complex with a single small molecule which stabilizes the dimer thus occluding the PD-1 interaction surface of PD-L1s. The small-molecule interaction "hot spots" on PD-L1 surfaces suggest approaches for the PD-1/PD-L1 antagonist drug discovery

Anodic oxidation of the Ti-13Nb-13Zr alloy

This work presents the results of the investigations on the electropolishing and anodic oxidation of the Ti–13Nb–13Zr titanium alloy. Electropolishing was conducted in the solution containing ammonium fluoride and sulfuric acid, whereas the solution of phosphoric acid was used for anodic oxidation of the alloy. The influence of electropolishing and anodization process parameters on the texture (scanning electron microscopy (SEM)) and chemical composition (X-ray photoelectron spectroscopy (XPS)) of the surface layer was established. Electrochemical impedance spectroscopy in 5 % NaCl solution was used for the determination of the corrosion resistance of the alloy

Cutting Mechanics and Surface Finish for Turning with Differently Shaped CBN Tools

In this paper, the basic cutting characteristics such as cutting forces, cutting power and its distribution, specific cutting energies were determined taking into account variable tool corner radius ranging from 400 to 1200 µm and constant cutting parameters typical for hard turning of a hardened 41Cr4 alloy steel of 55±1 HRC hardness. Finish turning operations were performed using chamfered CBN tools. Moreover, selected roughness profiles produced for different tool corner radius were compared and appropriate surface roughness parameters were measured. The measured values of Ra and Rz roughness parameters are compared with their theoretical values and relevant material distribution curves and bearing parameters are presented

Cloning, expression and purification of recombinant protein PG0023 from secretion system of Porphyromonas gingivalis W83

Porphyromonas gingivalis jest głównym patogenem odpowiedzialnym za rozwój paradontozy, choroby dotykającej około 30% dorosłej populacji ludzkiej w krajach wysoko rozwiniętych. Bakteria rozwija się głównie w kieszonkach przyzębnych dzięki wydzielaniu do najbliższego otoczenia dużej liczby czynników wirulencji, w tym dobrze już poznanych enzymów proteolitycznych. Wydzielanie czynników wirulencji P. gingivalis na zewnątrz komórki zachodzi poprzez nowy, wcześniej nieznany system sekrecji. Dotychczasowe badania ukazały, że w jego skład wchodzi co najmniej siedem białek błonowych i periplazmatycznych przy czym w literaturze opisano do tej pory jedynie cztery z nich - Sov, PorT, PG0023, PG0534. W prezentowanej pracy sklonowano gen pg0023 do wektora ekspresyjnego pETDuet-1 w celu otrzymania konstruktu z metką histydynową na N-końcu białka. Wykonano optymalizację warunków ekspresji białka z użyciem dwóch szczepów ekspresyjnych E. coli. Znaczna ekspresja białka do ciałek inkluzyjnych wymusiła zastosowanie warunków denaturującyh w celu otrzymania białka w formie rozpuszczalnej. Wstępny etap oczyszczania obejmował płukanie otrzymanych podczas ekspresji ciałek inkluzyjnych. Tak przygotowane białko poddawano refoldingowi oraz oczyszczaniu metodą chromatografii powinowactwa. Zwinięte białko PG0023 otrzymane metodą refoldingu przez dializy poddano sączeniu molekularnemu w celu sprawdzenia czy tworzy ono struktury IV-rzędowe. Uzyskany wynik świadczy prawdopodobnie o dimeryzacji białka. W celu sprawdzenia czy otrzymane białko uzyskało poprawną konformację, przeprowadzono analizę zależnej od temperatury ruchliwości elektroforetycznej w żelu poliakrylamidowym. Otrzymane rezultaty ukazały brak cech charakterystycznych dla białka o strukturze β-beczki. Wyniki degradacji otrzymanego białka przez wybrane proteazy występujące w jego otoczeniu ukazały, że białko pozbawione błonowego otoczenia jest nieodporne na proteolizę.Porphyromonas gingivalis is a major pathogen in destructive periodontal diseases in humans, which affects about 30% of human adult population worldwide. The bacterium grows mainly in periodontal pockets through secretion of a large number of virulence factors, including the well-known proteolytic enzymes, gingipains. Secretion of virulence factors outside the cell of P. gingivalis occurs through a new, previously unknown secretion system. Previous studies have shown that it comprises at least seven membrane and periplasmic proteins, but only four of them have been described in the literature so far - SOV, Port, PG0023, PG0534.The present study presents a process of cloning pg0023 gene to an expression vector pETDuet-1 in order to achieve a construct with HisTag at the N-terminal of the protein. To optimize the conditions of the protein expression two bacterial strains of E. coli were used. The high level of expression of the protein to inclusion bodies imposed the usage of denaturating conditions to convert a protein into a soluble form. Initial purification phase included rinsing inclusion bodies. Afterwards, prepared protein was refolded and purified by affinity chromatography. Folded protein PG0023 obtained by the dialysis refolding-method. It was then analyzed by the size exclusion chromatography in order to determine if it has adopted a quaternary structure. Obtained result proves that protein probably dimerize. In order to check if protein has correct conformation, the temperature-dependent-mobility in SDS PAGE test was performed. The results revealed no features typical for β-barrel protein in analyzed samples. Outcomes acquired by protein degradation by selected proteases present in protein’s environment proved that the protein devoided its natural membrane environment is sensitive to proteolysis