Porous Silicon Nanodiscs for Targeted Drug Delivery

There is a strong demand for techniques that allow the fabrication of biocompatible porous nanoparticles for drug delivery applications. In this work, a new method to fabricate size‐ and shape‐controlled porous silicon (pSi) nanodiscs is described. The process relies on a combination of colloidal lithography and metal‐assisted chemical etching. Height and diameter of the pSi nanodiscs can be easily adjusted. The nanodiscs are degradable in physiological milieu and are nontoxic to mammalian cells. In order to highlight the potential of the pSi nanodiscs in drug delivery, an in vitro investigation that involved loading of nanodiscs with the anticancer agent camptothecin and functionalization of the nanodisc periphery with an antibody that targets receptors on the surface of neuroblastoma cells is carried out. The thus‐prepared nanocarriers are found to selectively attach to and kill cancer cells.     

Combining microsatellite markers and capillary gel electrophoresis with laser-induced fluorescence to identify the grape (Vitis vinifera) variety of musts

In this work, a new method that combines the use of microsatellite markers (VVMD5 and ZAG79) together with capillary gel electrophoresis with laser-induced fluorescence (CGE–LIF) is developed and applied to the identification of Albariño and Moscatel Grano Menudo musts. The GCE-LIF method uses commercially available products including polymers, DNA-intercalating dyes and bare fused silica capillaries to provide reproducible and sensitive separations of DNA fragments for grapevine characterization. The CGE–LIF procedure offers highly resolved separations of DNA fragments from 48 to 1031 bp in ca. 30 min with efficiencies up to 1.8×10⁶ plates/m allowing the separation of fragments that differ in 4 bp. The use of different DNA standards (i.e., 100 bp ladder, Ф×174 and pBR322) and their effect on size assignment of the amplified DNA is also investigated. It is demonstrated that the microsatellite markers (VVMD5 and ZAG79) provide DNA amplification patterns specific for Albariño and Moscatel Grano Menudo grapes that can be adequately differentiated by using CGE–LIF. Moreover, the DNA sizes determined by this CGE–LIF method are corroborated using a more standard procedure (i.e., an automatic genetic analyzer with a commercial kit) demonstrating the usefulness of this new methodology.     

Resolution with vascular endoprosthesis after first angioplasty failure in the treatment of post-transplant stenosis of the renal artery

A thermal desorption-gas chromatography (GC) system was developed for use with commercial adhesive plasters used for monitoring exposure of hands to common solvents. The efficiency of solvent adsorption on the activated carbon pads located on the plasters was determined for acetone, trichloroethylene, D-limonene, methanol, ethyl methyl ketone, toluene, tetrachloroethylene and m-xylene. The degree of solvent recovery for the system was also investigated for each solvent, as was its sensitivity and reproducibility. All solvents exhibited > 90% adsorption on the pads at spiking levels of 100-200 ng for each solvent, except for m-xylene and d-limonene. Solvent recovery was dependent on the volatility of the solvent at spiking volumes of about 1 microliter per pad with solvents with boiling points above 110 degrees C showing recoveries of < 75%. Increasing primary desorption times and temperatures increased these values. The precision was good with RSD < 5% for all solvents over the range 0.5-5.0 microliters of applied solvent. It was possible to detect 15-60 ng of each solvent component within solvent mixtures on the pads with the exception of D-limonene. It is concluded that all solvents tested except D-limonene can be determined on the pads under the conditions for thermal desorption-GC analysis described. The pads were used under protective gloves with six workers using xylene isomers as solvent in the workplace, when apparent solvent breakthrough through their gloves was observed.     

Geographic isolation in the geriatric population of a rural town

OBJECTIVE: To estimate the prevalence and characteristics of geographic isolation in the elder people from Alora (Málaga). DESIGN: A transversal observational study. SETTING: Town of Alora. PATIENTS OR OTHER PARTICIPANTS: Elder people of both sexes, who lives habitually in Alora and born in 1927 or before. Home interview in a 153 individuals random sample proceeding from actual census during june to september 1992. MEASUREMENTS AND MAIN RESULTS: We found 25 individuals with the isolation conditions being the 16.34% (IC 95%: 10.48-22.20). In the 24% of them (IC 95%: 11.5-43.4) we found dependence of other person for two and more basic functions in the current life. Half of them this deficits are cover by the couple, the rest depends on their sons. We didn't found significative differences in none variables with the urban group. CONCLUSIONS: The geographic isolation affect to an important proportion of elder people in rural areas and must be used in the designs of care elderly programs.     

Estimation of the percentage of transgenic Bt maize in maize flour mixtures using perfusion and monolithic reversed-phase high-performance liquid chromatography and chemometric tools

The estimation of the percentage of transgenic Bt maize in maize flour mixtures has been achieved in this work by high-performance liquid chromatography using perfusion and monolithic columns and chemometric analysis. Principal component analysis allowed a preliminary study of the data structure. Then, linear discriminant analysis was used to develop decision rules to classify samples in the established categories (percentages of transgenic Bt maize). Finally, linear regression (LR) and multivariate regression models (namely, principal component analysis regression (PCR), partial least squares regression (PLS-1), and multiple linear regression (MLR)) were assayed for the prediction of the percentages of transgenic Bt maize present in a maize flour mixture. Using the relative areas of the protein peaks, MLR provided the best models and was able to predict the percentage of transgenic Bt maize in flour mixtures with an error of ±5.3%, ±2.3%, and ±3.8% in the predictions of Aristis Bt, DKC6575, and PR33P67, respectively.     

Rapid characterisation of (glyphosate tolerant) transgenic and non-transgenic soybeans using chromatographic protein profiles

The characterisation of transgenic and non-transgenic soybeans was performed in this work based on the examination of their protein profiles obtained by rapid chromatographic techniques. Two reversed-phase chromatographic methods using monolithic and perfusion stationary phases were applied to the separation of soybean proteins from different transgenic and non-transgenic soybeans. The development of the monolithic LC methodology was carried out through the study of the influence of different parameters such as gradient, ion-pairing reagent, and temperature on the separation of soybean proteins. Results from monolithic LC analysis were compared with those obtained by perfusion LC using a method previously developed by our research team. Perfusion and monolithic LC enabled the separation of soybean proteins in less than 3 and 8 min, respectively. In both cases, there were certain features in the chromatograms that seemed to be characteristic of transgenic samples. A deeper analysis of chromatographic profiles was then performed by the application of multivariate classification techniques. Results from these multivariate techniques showed that the two methods presented similar classification capabilities being both suitable for the characterisation of transgenic and non-transgenic soybeans. A more robust mathematical model was built with the data obtained by the perfusion method using 10 additional samples for training (a total of 26 samples), obtaining a 96.2% of correct classification. This model was validated by a cross-validation procedure (80.8% of correct classification) and by the correct classification of 15 out of 16 blind samples.     

Fuel-cell grade hydrogen production by coupling steam reforming of ethanol and carbon monoxide removal

Challenges of coupling steam reforming of ethanol (SRE) and carbon monoxide (CO) removal to continuous fuel-cell grade hydrogen (H₂) production were assessed. A SRE reactor, based on a previous optimized RhPt/CeO₂SiO₂ catalyst, was coupled to a CO removal reactor, based on AuCu/CeO₂ catalysts with different Au:Cu weight ratios. Fuel-cell grade H₂ was achieved with a Au_1.0Cu_1.0/CeO₂ catalyst at 210 °C on the CO removal reactor. AuCu/CeO₂ catalysts characterization suggests that Au favors CO conversion by the formation of possible Au⁰-CO_ad species, and Cu improves CO₂ yield by promoting oxygen vacancies on CeO₂. However, operando DRIFTS by 95 h showed that Au_1.0Cu_1.0/CeO₂ catalyst is susceptible to deactivation by the diminish on the CO_ad species and oxygen vacancies, and the formation of carbonate species. These results allowed us to propose a cyclic reduction treatment to prevent catalyst deactivation of Au_1.0Cu_1.0/CeO₂ (95 h of time-on-stream) while producing fuel-cell grade H₂.     

Hormone dependence in functional thyroid cancers, survival after total thyroidectomy combined with radioactive iodine and thyroid extract therapy

The authors reviewed current criteria on hormone-dependence in functional thyroid cancers, presenting data of compared disease evolution based on the casuistics of thyroid carcinomas from the files of the Fundación Jiménez Díaz, with 5 and 10 year follow-up studies in some of the cases. They found a higher number of survivors among the patients with papilliferous carcinoma in both 5 and 10 year follow-up groups whom, aside total surgical removal of the gland and the administration of thyroid extracts, those who had thyroid residues left were given 100 mc of 131I. Among the patients with follicular adenocarcinoma, under the same comparative conditions, differences were not very clear in the 5 year follow-up group, while the 10 year follow-up group showed marked differences. The authors conclude that an adequate combination of the three therapeutic procedures may allow a higher survival rate.     

Anaerobic methane oxidation in a landfill-leachate plume

The alluvial aquifer adjacent to Norman Landfill, OK, provides an excellent natural laboratory for the study of anaerobic processes impacting landfill-leachate contaminated aquifers. We collected groundwaters from a transect of seven multilevel wells ranging in depth from 1.3 to 11 m that were oriented parallel to the flow path. The center of the leachate plume was characterized by (1) high alkalinity and elevated concentrations of total dissolved organic carbon, reduced iron, and methane, and (2) negligible oxygen, nitrate, and sulfate concentrations. Methane concentrations and stable carbon isotope (delta13C) values suggest anaerobic methane oxidation was occurring within the plume and at its margins. Methane delta13C values increased from about -54 per thousand near the source to > -10 per thousand downgradient and at the plume margins. The isotopic fractionation associated with this methane oxidation was -13.6+/-1.0 per thousand. Methane 13C enrichment indicated that 80-90% of the original landfill methane was oxidized over the 210-m transect. First-order rate constants ranged from 0.06 to 0.23 per year, and oxidation rates ranged from 18 to 230 microM/y. Overall, hydrochemical data suggest that a sulfate reducer-methanogen consortium may mediate this methane oxidation. These results demonstrate that natural attenuation through anaerobic methane oxidation can be an important sink for landfill methane in aquifer systems.     

A low-capacitance bipolar/BiCMOS isolation technology. II. Circuitperformance and device self-heating

For pt. 1 see ibid., vol. 41, no. 8, p. 1379-87 (1994). Device and circuit results from transistors fabricated with a novel bipolar isolation technology are presented and discussed. The isolation structure, called sequentially planarized interlevel isolation technology (SPIRIT), is fabricated by using a combination of selective epitaxial growth of silicon and a preferential polishing technique as the key process elements. This structural concept aims for reduced collector-substrate and collector-base capacitances, as well as a lower extrinsic base contact resistance, in a partial-SOI structure without significantly increasing the device temperature during operation. The feasibility of the isolation structure is demonstrated through ECL ring oscillators with gate delays of 23.6 ps at 0.72 mA and 47 ps at 0.23 mA. The temperature contours for SPIRIT and other bipolar isolation structures are simulated by using a finite-element method. It is shown that the capacitance versus self-heating tradeoff of SPIRIT is significantly improved over that of conventional trench or SOI isolation structures