Machining of Aluminum Alloy

Import 23/07/2015Diplomová práce se zabývá kvalitou opracované hliníkové slitiny EN AW-6082, speciálně drsností povrchu a měřením a vyhodnocením složek řezných sil. Teoretická část objasňuje základní pojmy věnované čelnímu frézování, obrobitelnosti hliníku, obráběným materiálům, řezným podmínkám a geometrii obrábění. V návrhu experimentální části práce je popsáno použití stroje, nástroje a vyměnitelných břitových destiček, přístrojů na měření drsnosti, velikosti řezných sil a navržené řezné podmínky. V experimentální části práce jsou změřeny drsnosti povrchu a presentovány výsledky naměřených hodnot drsnosti Ra a Rz. Řezné síly byly měřeny na piezoelektrickém dynamometru.This master thesis is concerned with the quality of machined aluminium alloy EN AW-6082, especially surface roughness and the measurement and evaluation components of the cutting forces. The theoretical part explains the basic concepts of frontal milling, machinability aluminium, machined material, cutting conditions and geometry processing. In the proposal of the experimental part is described the using of machine, tool and indexable inserts, devices for measuring roughness, cutting forces and proposed cutting conditions. In the experimental part of the work are measured surface roughnesses and presented the results of the measured values of roughness Ra and Rz. Cutting forces were measured on the piezoelectric dynamometer.346 - Katedra obrábění, montáže a strojírenské metrologievelmi dobř

El Diario de Pontevedra : periódico liberal: Ano XXVII Número 7794 - 1910 maio 2

Meta-analysis revealed similar hospital stay in RAMPS and standard procedure. (PNG 9 kb

The Presence of the Y-Chromosome, Not the Absence of the Second X-Chromosome, Alters the mRNA Levels Stored in the Fully Grown XY Mouse Oocyte

<div><p>The oocytes of B6.Y^TIR sex-reversed female mouse mature in culture but fail to develop after fertilization because of their cytoplasmic defects. To identify the defective components, we compared the gene expression profiles between the fully-grown oocytes of B6.Y^TIR (XY) females and those of their XX littermates by cDNA microarray. 173 genes were found to be higher and 485 genes were lower in XY oocytes than in XX oocytes by at least 2-fold. We compared the transcript levels of selected genes by RT-PCR in XY and XX oocytes, as well as in XO oocytes missing paternal X-chromosomes. All genes tested showed comparable transcript levels between XX and XO oocytes, indicating that mRNA accumulation is well adjusted in XO oocytes. By contrast, in addition to Y-encoded genes, many genes showed significantly different transcript levels in XY oocytes. We speculate that the presence of the Y-chromosome, rather than the absence of the second X-chromosome, caused dramatic changes in the gene expression profile in the XY fully-grown oocyte.</p> </div

RT-PCR detection of X-encoded gene transcripts in XX, XO and XY oocytes.

<p>A. Agarose gel electrophoresis stained with ethidium bromide. S, 100 bp ladders. B. Relative transcript levels. In each set of experiment, the transcript levels were normalized against the mean of two β-actin controls. Each column indicates the mean ± SEM (n = 6 for <i>Xiap</i> and n = 3 for others except for <i>Usp9x</i> in XO, n = 1). a and b above columns indicate statistical differences at P<0.05 by paired students t-test.</p

Relative transcript levels of <i>Epas1</i> in XX, XO and XY oocytes collected from ovaries at 10 and 30 days after birth.

<p>“Growing oocytes” were selected for their diameter between 40 and 50 µm. “Fully grown oocytes” were denuded from oocyte-cumulus complexes of antral follicles. The transcript levels were normalized against the mean of two β-actin controls. Each column indicates the mean ± SEM (n = 3). A and B above columns denote statistical differences at P<0.01 by paired students t-test.</p

Response time of flight initiation.

<p>For each tested beetle, the (a) left, (b) middle, and (c) right columns indicate the average response times of the first 5 trials, all 10 trials, and the last 5 trials, respectively. The bar in each graph indicates the standard deviation.</p

Anatomical view of pairs of the antagonistic flight muscles, namely, the dorsal longitudinal muscle (DLM) and dorsal ventral muscle (DVM).

<p>(A) Overview of the dorsal side of a beetle, with the locations of implantation site at scutellum and head. The electrodes go through the holes made in the scutellum into DLM and head into optical lobes. Magnified views of dorsal thorax after (B) removal of scutellum, (C) removal of elytra, (D) exposing DLM, and (E) exposing DVM.</p

The response time is the elapsed time from the beginning of the electrical stimulation to the beginning of flight (first wing beat).

<p>The response time was counted by means of frame-by-frame playback between the trigger and the first wing beat, as recorded by a video recorder.</p

Propylene Glycol-Linked Amino Acid/Dipeptide Diester Prodrugs of Oleanolic Acid for PepT1-Mediated Transport: Synthesis, Intestinal Permeability, and Pharmacokinetics

In our previous studies, ethylene glycol-linked amino acid diester prodrugs of oleanolic acid (OA), a Biopharmaceutics Classification System (BCS) class IV drug, designed to target peptide transporter 1 (PepT1) have been synthesized and evaluated. Unlike ethylene glycol, propylene glycol is of very low toxicity in vivo. In this study, propylene glycol was used as a linker to further compare the effect of the type of linker on the stability, permeability, affinity, and bioavailability of the prodrugs of OA. Seven diester prodrugs with amino acid/dipeptide promoieties containing l-Val ester (<b>7a</b>), l-Phe ester (<b>7b</b>), l-Ile ester (<b>7c</b>), d-Val-l-Val ester (<b>9a</b>), l-Val-l-Val ester (<b>9b</b>), l-Ala-l-Val ester (<b>9c</b>), and l-Ala-l-Ile ester (<b>9d</b>) were designed and successfully synthesized. In situ rat single-pass intestinal perfusion (SPIP) model was performed to screen the effective permeability (<i>P</i>_eff) of the prodrugs. <i>P</i>_eff of <b>7a</b>, <b>7b</b>, <b>7c</b>, <b>9a</b>, <b>9b</b>, <b>9c</b>, and <b>9d</b> (6.7-fold, 2.4-fold, 1.24-fold, 1.22-fold, 4.15-fold, 2.2-fold, and 1.4-fold, respectively) in 2-(<i>N</i>-morpholino)­ethanesulfonic acid buffer (MES) with pH 6.0 showed significant increase compared to that of OA (<i>p</i> < 0.01). In hydroxyethyl piperazine ethanesulfonic acid buffer (HEPES) of pH 7.4, except for <b>7c</b>, <b>9a</b>, and <b>9d</b>, <i>P</i>_eff of the other prodrugs containing <b>7a</b> (5.2-fold), <b>7b</b> (2.0-fold), <b>9b</b> (3.1-fold), and <b>9c</b> (1.7-fold) exhibited significantly higher values than that of OA (<i>p</i> < 0.01). In inhibition studies with glycyl-sarcosine (Gly-Sar, a typical substrate of PepT1), <i>P</i>_eff of <b>7a</b> (5.2-fold), <b>7b</b> (2.0-fold), <b>9b</b> (3.1-fold), and <b>9c</b> (2.3-fold) had significantly reduced values (<i>p</i> < 0.01). Compared to the apparent permeability coefficient (<i>P</i>_app) of OA with Caco-2 cell monolayer, significant enhancement of the <i>P</i>_app of <b>7a</b> (5.27-fold), <b>9b</b> (3.31-fold), <b>9a</b> (2.26-fold), <b>7b</b> (2.10-fold), <b>7c</b> (2.03-fold), <b>9c</b> (1.87-fold), and <b>9d</b> (1.39-fold) was also observed (<i>p</i> < 0.01). Inhibition studies with Gly-Sar (1 mM) showed that <i>P</i>_app of <b>7a</b>, <b>9b</b>, and <b>9c</b> significantly reduced by 1.3-fold, 1.6-fold, and 1.4-fold (<i>p</i> < 0.01), respectively. These results may be attributed to PepT1-mediated transport and their differential affinity toward PepT1. According to the permeability and affinity, <b>7a</b> and <b>9b</b> were selected in the pharmacokinetic studies in rats. Compared with group OA, <i>C</i>_max for group <b>7a</b> and <b>9b</b> was enhanced to 3.04-fold (<i>p</i> < 0.01) and 2.62-fold (<i>p</i> < 0.01), respectively. AUC_0→24 was improved to 3.55-fold (<i>p</i> < 0.01) and 3.39-fold (<i>p</i> < 0.01), respectively. Compared to the ethylene glycol-linked amino acid diester prodrugs of OA in our previous work, results from this study revealed that part of the propylene glycol-linked amino acid/dipeptide diester prodrugs showed better stability, permeability, affinity, and bioavailability. In conclusion, propylene glycol-linked amino acid/dipeptide diester prodrugs of OA may be suitable for PepT1-targeted prodrugs of OA to improve the oral bioavailability of OA

Combination of Amino Acid/Dipeptide with Nitric Oxide Donating Oleanolic Acid Derivatives as PepT1 Targeting Antitumor Prodrugs

By taking advantage of the cytotoxic effect of nitric oxide (NO) and PepT1 for molecule-targeted drug delivery, a series of amino acid/dipeptide diester prodrugs of NO-donating oleanolic acid derivatives were designed and synthesized. Two prodrugs <b>6a</b> and <b>8a</b> showed potent cytotoxcity, which is probably due to their high PepT1 affinity and NO-releasing ability. Furthermore, the aqueous solubility of the prodrugs was also significantly enhanced because of the hydrophilic amino acid/dipeptide promoiety