A single dose of caffeic acid phenethyl ester prevents initiation in a medium-term rat hepatocarcinogenesis model

AIM： To study of the effect of caffeic acid phenethyl ester （CAPE） on the initiation period in a medium-term assay of hepatocarcinogenesis. METHODS： Male Wistar rats were subjected to a carcinogenic treatment （CT） and sacrificed at 25^th d; altered hepatic foci （AHF） were generated efficiently. To a second group of rats a single 20 mg/kg doses of CAPE was given 12 h before initiation with CT and were sacrificed at 25^th d. We evaluated the expression of preneoplastic markers as Y-glutamyltranspeptidase （GGT） and glutathione S-transferase type pi protein （GSTp） by histochemistry, RT-PCR and Western blot analyses, respectively. We measured thiobarbituric acid reactive substances （TBARS） in homogenates of liver and used Unscheduled DNA Synthesis （UDS） assay by incorporation of [^3H] thymidine （^3HdT） in primary hepatocyte cultures （PHC）. RESULTS： At 25^th d after CT CAPE reduced the observed increase of GGT^＋AHF by 84% and liver expression ofggt mRNA by 100%. In case of the GSTp protein, the level was reduced by 90%. As indicative of oxidative stress generated by diethylnitrosamine （DEN） 12 h after its administration, we detected a 68% increase of TBARS. When CAPE was administered before DEN, it completely protected from liver TBARS induction. To have an indication of the sole effect of CAPE on initiation, two carcinogens were tested in a UDS assay in PHC, we used methyl-n-nitrosoguanidine as a direct carcinogen and DEN, as indirect carcinogen. In this assay, genotoxic damage caused by carcinogens was abolished at 5μM CAPE concentration. CONCLUSION： Our results demonstrated that CAPE possesses anti-genotoxic and antineoplastic capabilities, by an anti-oxidative and free-radical scavenging mechanism.

Microstructural evaluation and nanohardness of an AlCoCuCrFeNiTi high-entropy alloy

An AlCoCuCrFeNiTi high-entropy alloy(HEA) was prepared by mechanical alloying and sintering to study the effect of Ti addition to the widely studied AlCoCuCrFeNi system. The structural and microstructural characteristics were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM), and transmission electron microscopy(TEM). The formation of four micrometric phases was detected: a Cu-rich phase with a face-centered cubic(fcc) structure, a body-centered cubic(bcc) solid solution with Cu-rich plate-like precipitates(fcc), an ordered bcc phase, and a tetragonal structure. The XRD patterns corroborate the presence of a mixture of bcc-, fcc-, and tetragonal-structured phases. The Vickers hardness of the alloy under study was more than twice that of the AlCoCuCrFeNi alloy. Nanoindentation tests were performed to evaluate the mechanical response of the individual phases to elucidate the relationship between chemical composition, crystal structure, and mechanical performance of the multiphase microstructure of the AlCoCuCrFeNiTi HEA.

Preparation of neodymium-doped yttrium aluminum garnet powders and fibers

Using nitrate precursors, a novel spray-drying assisted citrate gel process for the preparation of neodymium-doped yttrium alumi- num garnet （YAG） phase was developed. Synthesis of single-phase polycrystalline YAG was achieved at temperatures as low as 800 ℃ using the spray-drying methodology whilst conventional approaches currently available require 1000 ℃. Initially, a solution was prepared by mixing aluminum and yttrium nitrates, citric acid, etilenglycol and neodymium oxide. This solution was dried by pulverization （spray dryer） to obtain aggregated precursor powders of the compound. These aggregates were calcined at 800, 850 and 900 ℃ to determine the phase evolution from amorphous to crystalline by X-ray diffraction （XRD）. The morphology of aggregates was characterized by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. Moreover, through XRD it was determined that the crystallization of YAG phase started at about 800 ℃ without any intermediate phases. The powders were composed of spherical aggregates with an average diameter of 1 um. From these powders, ceramic fibers with additions of 2at.% and 5at.% Nd, were extracted from the melt with diameters ranging from 30 um to 50 um.

Arsenic Removal from Zimapan Contaminated Water Monitored by the Tyndall Effect

In Zimapan Valley, Mexico, up to 1.1 mg·L-1 of arsenic concentrations have been detected in deep wells that are used as drinking water supply for almost 39,000 people, which could have been exposed to levels higher than 10 μg·L-1 of arsenic, the maximum level recommended by the World Health Organization. Chronic consumption of water contaminated with arsenic can cause several diseases, including cancer. For it, the implementation of practical and economical methods to remove arsenic from drinking water is crucial to protect the population health. In this work, an electrochemical method to remove arsenic from drinking water is described. The process, monitored by Tyndall effect, utilizes Cu2+ and Zn2+ ions from a brass electrode in an electrochemical cell with water as electrolyte. Results show that the EC process reduces the concentration of the arsenic diluted in Zimapan water to a level below the limit of detection of the atomic absorption spectrophotometer employed. Arsenic was removed through the formation of Cu and Zn arsenic compounds. Cu2+ and Zn2+ ions form a hydroxide and eventually polycrystalline precipitation of kottigite and cornubite complexes (identified by energy-dispersive X-ray spectroscopy and X-ray diffraction), which are then filtered to eliminate the precipitated arsenic compounds.

Morphometric Analysis on Shape Transition during Growth of the Red Snapper (<em>Lutjanus campechanus</em>, Poey, 1860)

The red snapper Lutjanus campechanus (Poey, 1860) has a high commercial value that sustains an important fishery in Mexico. In this study, the patterns in morphological variations from early juvenile to adult stages were assessed by geometric methods (GM) in 194 organisms. Changes in shape were more evident and rapid in the early juvenile stage and decreased during adulthood. The principal components analysis of shape (Relative Warp Analysis, or RWA) identified size and body depth as the main sources of variance associated to both juvenile and adult organisms. The outline of the head and the tail showed the most noticeable differences following the ontogenic pathway visualized by thin-plate splines indicating that the ontogenetic pathway of the upper half and the lower half of the dorsal head profile (DHP) are in relatively opposite directions than those from the tail that bends ventrally. The Two-Block Partial Least Square analysis (2B-PLS) and their CR coefficients showed that the two modules had a moderate linear trend (p = 0.001). Although the blocks have morphological changes at different rates, there is a moderate synchrony in growth by modules. This study is the first to report the use of geometrical morphometry in L. campechanus in Mexico.

Presence of Infectious Hypodermal and Haematopoietic Necrosis Virus (IHHNV) in Native Shrimps from Southern Mexico

A survey for Infectious Hypodermal and Haematopoietic Necrosis Virus (IHHNV) and White Spot Syndrome Virus (WSSV) was performed during two catching seasons of native shrimps in the Yucatan Coast in the Gulf of Mexico. The mtDNA COI barcode identified two endemic species;the southern pink shrimp Penaeus notialis (Pérez Fantante, 1967) and the northern pink shrimp Penaeus brasiliensis (Latreille, 1987) (previously described as Farfantepenaeus brasiliensis). The prevalence of IHHNV was of 18.18% in 2016, and of 8.57% in 2017. All organisms tested negative for WSSV. This is the first identification of wild shrimps in the state of Yucatan Mexico by mtDNA COI barcode as well as the first identification of IHHNV in such species. The presence of IHHNV in wild shrimps populations has a potential of persisting in the coast of Yucatan with putative detrimental effect on local fisheries because once established in natural waters and hosts;such pathogens are almost impossible to eradicate.

Comparative Study between D2EHPA and Cyanex 272 as Extractants of Mn(II) from a Leached Liquor Produced by Reductive Leaching of a Pyrolusite Ore with SO₂

This paper compares the efficiency of D2EHPA and Cyanex 272 to extract the divalent manganese cation from an actual leaching solution obtained by reductive leaching of a low-grade pyrolusite ore, using SO2 gas. The studied variables were the extractant concentration in the organic phase, the pH of the leached liquor and the volume ratio between organic phase and leached liquor. It was observed that D2EHPA is a better extractant than Cyanex272. Therefore, with the best experimental conditions found, both extractants reach a manganese recovery around 95% with five extraction stages conducted under the following conditions: 25?C, O/A = 2, 10% volume of extractant concentration in the organic phase, pH of the leached liquor before the mixing between 8 and 8.5, and one minute of mixing time for each extraction stage.

In Silico Analysis of the Cross-Reactivity of Pacific White Shrimp (Litopenaeus vannamei) Allergens with Other Arthropod Species

This study provided new data in the area of cross-reactivity for Pacific white shrimp (Litopenaeus vannamei). Although the cross-reactivity between the most prominent allergenic proteins of shrimp and other crustaceans has been extensively studied, few data are showing the frequency of arthropod-shrimp Litopenaeus vannamei cosensitization in an in silico analysis. A comparative analysis of “typical and non-typical” shrimp L. vannamei allergens with other species was achieved, revealing new allergens and previously characterized shrimp allergens, which validated the comprehensive identification approach used in this study. Importantly, up to 192, amino acid sequences were identified that had matches to shrimp L. vannamei allergens that matched allergenic proteins in mites, insects, fish, bacteria, mammals, birds, and plants.

Early Detection of White Spot Syndrome Virus(WSSV)in Isolated Hemocytes of Litopenaeus vannamei

To date, White Spot Syndrome (WSS) produced by the White Spot Syndrome Virus (WSSV) causes one of the most severe diseases infecting penaeid shrimps worldwide. Although a vast amount of studies has elucidated pathogenesis in live infection models, there is still little information about the interaction of WSSV infections using in vitro models in the whiteleg shrimp Litopenaeus vannamei (L. vannamei) hemocytes. In this study, a WSSV infection kinetics was performed using total hemocytes isolated from healthy L. vannamei organisms and maintained in in vitro conditions using isotonic solution for shrimp (ISS). The infected experimental cells received ≈ 30,000 viral copies of WSSV. The viability of the hemocytes (control and infected group) was measured during the kinetics with trypan blue exclusion method and cells were maintained up to 6 hpi (post-infection) with non-significant differences of viability between both groups. WSSV replication was assessed using RT- PCR at the RNA expression level of the early viral gene Ie1 and transcripts were detected as early as 30 min pi. Hemocytes from WSSV group showed disrupted integrity, degranulation and irregular shape. This study provides evidence of the capability of WSSV to infect and replicates in L. vannamei hemocytes using in vitro assays in short times as 30 min.

Isolation and Characterization of Mercury Resistant Trichoderma Strains from Soil with High Levels of Mercury and Its Effects on Arabidopsis thaliana Mercury Uptake

Traditional mining activities are usually correlated with high levels of soil pollution, which is a major environmental concern. Extensive mining activities have taken place in the San Joaquin region in the State of Querétaro, México resulting in high levels of mercury soil pollution (up to 1532 ± 300 mg/kg). We isolated mercury-resistant fungal strains from the San Joaquin region soils and identified them through morphologic characteristics and ITS rDNA region sequence analysis. We determined that fungi isolated belong to the genus Trichoderma. All the isolates selected showed the ability to catalyze the volatilization of Hg. For air sampling, an active sampling device was constructed and using acid KMnO4 as an absorbent, the concentration of mercury in solution was determined through the cold vapor atomic absorption method. The results show mercury volatilization from the fungal species assay, with a maximum of 213.04 ± 32.6 μg/m3 while mycelium accumulation ranged from less than 17.5 ± 2.9 to 20.0 ± 3.4 μg/g. The fungal isolates were also evaluated for their ability to reduce mercury uptake in Arabidopsis thaliana. These observations suggest the utility of Trichoderma for the mobilization of mercury in those contaminated soils.

Piezoelectric Ceramic Controlled with Platinum Implant as New Isolator in ECG

Recently, a new PLZT bulk single plate, called ceramic-controlled piezoelectric with two Platinum wires (CCP2) has been produced;this CCP2 has two (250 μm of diameter and 1 cm long) Platinum-wire implants. This unconventional isolation device for use with diagnostic ECG devices provides high common mode rejection and low leakage current using piezo isolator based on two Platinum wires implanted Lead Lanthanum Zirconate Titanate bulk ceramic. These isolation was validated using four experimental setups;one of them determine that ceramic-controlled piezoelectric with two Platinum wires (CCP2) support up to 6 kV DC before it cracks (short cut). The second experimental setup determined high resistance about 3.9 × 109 Ω and 1.8 × 109 Ω measured on lateral sides and among Platinum wires of CCP2 respectively. The third experimental setup was to obtain the current leakage from CCP2 and it was 6 nA. The fourth experimental setup was to obtain frequency response that was the maximum up to 2.2 MHz and was a pass band filter. Finally the CCP2 was applied as new isolator in a ECG circuit, where bioelectrical ECG signal is modulating at 16 KHz using the piezoelectric effect obtaining excellent results.

Effect of Temperature and the Organic Phase Content on the Stripping of Mn(II) from a D2EPHA-KEROSENE Pseudo-Emulsion Using a Sulfuric Acid Aqueous Solution

There are few studies oriented to analyze the interaction between the variables of the stripping process of actual leaching solutions. The aim of this work was to study the effect of temperature and the percent of organic phase in the stripping pseudo-emulsion (D2EPHA and kerosene) on the manganese stripping process. Other studied variables were the acid concentration (H2SO4) in the aqueous phase, the percent of the organic phase in the pseudo-emulsion and the number of stripping stages. This information may be of interest to countries with radical temperature variations. It was discovered that in the range of 10?C to 50?C, temperature improves the depletion of manganese from the D2EPHA. Additionally, the percent of the organic phase should be less than 90% by volume of the pseudo-emulsion to favour the manganese exchange. Moreover, the H2SO4 concentration in the aqueous phase should be less than 1 M to avoid chemical instability of the organic phase.

Preparation and Characterization of Flexible, Transparent and Thermally Stable Aromatic Co-polyamides

Two aromatic co-polyamides were synthesized combining two diacid monomers containing bulky pendant groups, 5-(9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximido)isophthalic acid(DEAIA) and 5-tert-butylisophthalic acid(TERT), with 4,4′-(hexafluoroisopropylidene)dianiline(HFA) or 2,3,5,6-tetramethyl-1,4-phenylenediamine(Durene) by direct polycondensation. The structures of the obtained aromatic co-polyamides were confirmed by FTIR, Raman and 1 H-NMR. The co-copolyamide films, DHTH and DDTD, exhibited rms-roughness values between 0.94 and 1.60 nm, respectively. Moreover, they presented good thermal stability up to300 °C. Young's moduli of the co-polyamide films were between 4.1 and 4.3 GPa. X-ray diffraction results showed that the co-polyamide films were amorphous due to the incorporation of both bulky pendant groups, tert-butyl and dibenzobarrelene. The combination of bulky pendant groups provided intrinsically transparent co-polyamide films with a transmittance higher than 88% in the range of 400-780 nm.Due to these outstanding film and optical properties, they are suggested to be flexible substrates in applications for solar cell and other portable electronic devices.

Structural studies of BaTiO_3:Er^(3+) and BaTiO_3:Yb^(3+) powders synthesized by hydrothermal method

Erbium and ytterbium doped barium titanate nanopowders were prepared using the hydrothermal method. A barium titanate structure doped with rare earth ions manifested new characteristics and improved the field of application of optical devices such as trichromatic tubes, LCD displays, lamps, and infrared lasers. In this work, BaTiO3：Er3＋ and BaTiO3：Yb3＋ were prepared using barium chloride [BaCl2], titanium butoxide [C16H36O4Ti], erbium chloride [ErCl3] and ytterbium chloride [YbCl3] as precursors. Anhydrous methanol was employed as a solvent. Metallic potassium was used to promote solubility in the system and increase the pH to 13. This method yielded the formation of a predominantly cubic structure in both Er3＋ and Yb3＋ doped BaTiO3 powders. Characteristic bondings of BaTiO3 were observed with FT-IR spectroscopy. The predominantly cubic structure was confirmed by X-ray diffraction and micro-Raman analyses. The particle size（～30 nm） was estimated using the Scherrer equation and X-ray diffraction data. The results were presented and discussed.

Liver histological changes and lipid peroxidation in the amphibian Ambystoma mexicanum induced by sediment elutriates from the Lake Xochimilco

Lacustrine sediments accumulate pollutants that input from the lake watershed and can be released to the water column by sediment resuspension; thus, pollutants can change their bioavailability and exert adverse effects to aquatic biota. Shallow-urban lakes are particularly susceptible to receive pollutants from urban discharges and sediment resuspension. Lake Xochimilco, in Mexico City, an urban-shallow lake, faces multiple problems： urban sprawl, overexploitation of aquifers, drying of springs, discharge of wastewater from treatment plants, and sediment resuspension. The aquatic biota living in this ecosystem is continuously exposed to the release of pollutants from the sediments. We assessed the risk that pollutants released from sediments from Lake Xochimilco, Touristic（TZ） and Agriculture zone（AZ）, can exert on a native amphibian species of the lake（Ambystoma mexicanum） through exposure bioassays to sediment elutriates. We evaluate alterations in the amphibian by three approaches： biochemical（level of lipid peroxidation,LPO）, cellular（ultrastructure） and the liver histology of A. mexicanum and we compare them with a batch control. Additionally, we assessed heavy metals（Pb, Cd and Hg） in elutriates.Elutriates from TZ showed the highest concentrations of the metals assessed. Organisms exposed to sediment elutriates from either study sites showed higher LPO values than control organisms（p 〈 0.05）. Organisms exposed to elutriates from the TZ showed the most conspicuous damages： hepatic vasodilation of sinusoids, capillaries with erythrocytes,leukocyte infiltration and cytoplasmic vacuolation in hepatocytes. The biological responses assessed reflected the risk that faces A. mexicanum when is exposed for prolonged periods to sediment resuspension in Lake Xochimilco.

Effects of Silicon Nanoparticles on the Transient Liquid Phase Bonding of 304 Stainless Steel

Transient liquid phase （TLP） bonding of 304 stainless steel with nickel based filler metal, BNi-9, was performed to study the influence of silicon nanoparticles （NPs） on the mechanical and structural properties of the bonding area. It was found that silicon NPs act as a melting point depressant in the brazing process; the formation of silicon TLP induces the dissolution of elements of the metal filler and promotes a uniform distribution in the bonding area. Silicon NPs induce the development of smaller eutectic structures in the melting zone; it has been related to microhardness measurements, which are lower when the silicon NPs are used in the brazing process.

Effects of Gas1 on gliomas:a review on current preclinical studies

Glioblastoma multiforme(GBM)is the most common and lethal brain tumor.Its prognosis remains very poor,despite the use of combined treatments such as surgical resection,radiation and chemotherapy.The major limitations for the treatment of GBM are its high invasiveness,tumor recurrence and resistance to treatments.Therefore,gene therapy appears as a relevant strategy for its treatment.Thus,we have investigated the use of growth-arrest-specific 1(Gas1)for the treatment of GBM.Gas1 is a tumor suppressor protein that inhibits glioma growth by inducing arrest and apoptosis of tumor cells.Moreover,we have shown that a soluble form of Gas1 acting in both autocrine and paracrine manners is also effective inhibiting tumor growth in animal models,indicating its potential as an adjuvant for the treatment of GBM.