Enantioselective Crystallization of Sodium Chlorate in the Presence of Racemic Hydrophobic Amino Acids and Static Magnetic Fields

We study the bias induced by a weak (200 mT) external magnetic field on the preferred handedness of sodium chlorate crystals obtained by slow evaporation at ambient conditions of its saturated saline solution with 20 ppm of added racemic (dl) hydrophobic amino acids. By applying the Fisher test to pairs of experiments with opposing magnetic field orientation we conclude, with a confidence level of 99.7%, that at the water-air interface of this saline solution there is an enantioselective magnetic interaction that acts upon racemic mixtures of hydrophobic chiral amino acids. This interaction has been observed with the three tested racemic hydrophobic amino acids: dl-Phe, dl-Try and dl-Trp, at ambient conditions and in spite of the ubiquitous chiral organic contamination. This enantioselective magnetic dependence is not observed when there is only one handedness of added chiral amino-acid, if the added amino acid is not chiral or if there is no additive. This effect has been confirmed with a double blind test. This novel experimental observation may have implications for our view of plausible initial prebiotic scenarios and of the roles of the geomagnetic field in homochirality in the biosphere.This research was supported by the Instituto Nacional de Técnica Aerospacial (INTA) and by the grant AYA2006-15648-C02-02 of the Ministerio de Educación y Ciencia (Spain) and by the project grants AYA2011-25720 and AYA2012-38707 of MINECO (Spain).We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).Peer reviewe

Controlled delivery of tauroursodeoxycholic acid from biodegradable microspheres slows retinal degeneration and vision loss in P23H rats

Successful drug therapies for treating ocular diseases require effective concentrations of neuroprotective compounds maintained over time at the site of action. The purpose of this work was to assess the efficacy of intravitreal controlled delivery of tauroursodeoxycholic acid (TUDCA) encapsulated in poly(D, L-lactic-co-glycolic acid) (PLGA) microspheres for the treatment of the retina in a rat model of retinitis pigmentosa. PLGA microspheres (MSs) containing TUDCA were produced by the O/W emulsion-solvent evaporation technique. Particle size and morphology were assessed by light scattering and scanning electronic microscopy, respectively. Homozygous P23H line 3 rats received a treatment of intravitreal injections of TUDCA-PLGA MSs. Retinal function was assessed by electroretinography at P30, P60, P90 and P120. The density, structure and synaptic contacts of retinal neurons were analyzed using immunofluorescence and confocal microscopy at P90 and P120. TUDCA-loaded PLGA MSs were spherical, with a smooth surface. The production yield was 78%, the MSs mean particle size was 23 mu m and the drug loading resulted 12.5 +/- 0.8 mu g TUDCA/mg MSs. MSs were able to deliver the loaded active compound in a gradual and progressive manner over the 28-day in vitro release study. Scotopic electroretinografic responses showed increased ERG a- and b-wave amplitudes in TUDCA-PLGA-MSstreated eyes as compared to those injected with unloaded PLGA particles.TUDCA-PLGAMSs- treated eyes showed more photoreceptor rows than controls. The synaptic contacts of photoreceptors with bipolar and horizontal cells were also preserved in P23H rats treated with TUDCA-PLGA MSs. This work indicates that the slow and continuous delivery of TUDCA from PLGA-MSs has potential neuroprotective effects that could constitute a suitable therapy to prevent neurodegeneration and visual loss in retinitis pigmentosa

Risk factors for non-diabetic renal disease in diabetic patients

Background. Diabetic patients with kidney disease have a high prevalence of non-diabetic renal disease (NDRD). Renal and patient survival regarding the diagnosis of diabetic nephropathy (DN) or NDRD have not been widely studied. The aim of our study is to evaluate the prevalence of NDRD in patients with diabetes and to determine the capacity of clinical and analytical data in the prediction of NDRD. In addition, we will study renal and patient prognosis according to the renal biopsy findings in patients with diabetes. Methods. Retrospective multicentre observational study of renal biopsies performed in patients with diabetes from 2002 to 2014. Results. In total, 832 patients were included: 621 men (74.6%), mean age of 61.7 6 12.8 years, creatinine was 2.8 6 2.2 mg/dL and proteinuria 2.7 (interquartile range: 1.2–5.4) g/24 h. About 39.5% (n ¼ 329) of patients had DN, 49.6% (n ¼ 413) NDRD and 10.8% (n ¼ 90) mixed forms. The most frequent NDRD was nephroangiosclerosis (NAS) (n ¼ 87, 9.3%). In the multivariate logistic regression analysis, older age [odds ratio (OR) ¼ 1.03, 95% CI: 1.02–1.05, P < 0.001], microhaematuria (OR ¼ 1.51, 95% CI: 1.03–2.21, P ¼ 0.033) and absence of diabetic retinopathy (DR) (OR ¼ 0.28, 95% CI: 0.19–0.42, P < 0.001) were independently associated with NDRD. Kaplan–Meier analysis showed that patients with DN or mixed forms presented worse renal prognosis than NDRD (P < 0.001) and higher mortality (P ¼ 0.029). In multivariate Cox analyses, older age (P < 0.001), higher serum creatinine (P < 0.001), higher proteinuria (P < 0.001), DR (P ¼ 0.007) and DN (P < 0.001) were independent risk factors for renal replacement therapy. In addition, older age (P < 0.001), peripheral vascular disease (P ¼ 0.002), higher creatinine (P ¼ 0.01) and DN (P ¼ 0.015) were independent risk factors for mortality. Conclusions. The most frequent cause of NDRD is NAS. Elderly patients with microhaematuria and the absence of DR are the ones at risk for NDRD. Patients with DN presented worse renal prognosis and higher mortality than those with NDRD. These results suggest that in some patients with diabetes, kidney biopsy may be useful for an accurate renal diagnosis and subsequently treatment and prognosis

The effect of stirring on sodium chlorate crystallization under symmetry breaking conditions

6 pages, 3 figures, 1 table.-- PACS classification codes: 81.10.Dn; 64.60.Qb; 67.57.Pq; 02.70.Rr.The effect of the stirring rate on the crystallization of sodium chlorate was studied in more than 200 experiments using a set-up that allows to perform sets of 20 simultaneous experiments. The crystallization conditions were those that according to previous results lead to only one of both L and D enantiomorphic forms under stirring. The probability of D crystallization was determined using a statistical analysis based on the central limit theorem. The stirring dependence of induction times and crystal size distribution is reported. The stirring effect was correlated with differences between surface and bulk crystallization. The probability of D crystallization was detected to be slightly higher than that of the L, in contradiction with some previous reports, and that might be attributed to the chiral contamination of the bio-organic world on the starting materials and on the system. Our analysis allows to detect that the D-enantiomorph induction by chiral contamination occurs mainly in the nucleation at the interface air/water, which can be related to the expected higher concentration of the contaminants (bioorganic chiral amphiphiles e.g. DNA or proteins) on the surface of the solution.The authors are thankful to the Centro de Astrobiología (CAB) and to the Research Project No AYA2006-15648-CO2-02 from Spanish Ministry of Education and Science. One of us (MAH) gratefully acknowledges support from the Universidad Complutense through Acción Especial AES/06-14364.Peer reviewe

Prebiotic microreactors: A synthesis of purines and dihydroxy compounds in aqueous aerosol

20 pages, 9 figures, 3 tables, 1 appendix.-- Published online: 29 Nov. 2006.We report the synthesis of purine bases and other heterocycles and the formation of amino acids, hydroxy acids and dihydroxy compounds by the spark activation of an atmosphere of methane, nitrogen and hydrogen, in the presence of an aqueous aerosol. With the aid of the interface air–water, the organic material obtained shows greater amounts and diversity of molecules with biological interest than the products obtained in the absence of an aerosol. Our results support the suggestion that aerosols may have played a significant role in the prebiotic origin of molecular diversity and evolution.The authors acknowledge the Centro de Astrobiología (CAB) for the research facilities and the grants from Instituto Nacional de Técnica Aeroespacial ‘Esteban Terradas’ (INTA).Peer reviewe

The effects of ferrous and other ions on the abiotic formation of biomolecules using aqueous aerosols and spark discharges

15 pages, 4 figures, 3 tables.-- PMID: 17899439 [PubMed].-- ISI Article Identifier: 000251368300004.-- Printed version published Dec 2007.It has been postulated that the oceans on early Earth had a salinity of 1.5 to 2 times the modern value and a pH between 4 and 10. Moreover, the presence of the banded iron formations shows that Fe(+2) was present in significant concentrations in the primitive oceans. Assuming the hypotheses above, in this work we explore the effects of Fe(+2) and other ions in the generation of biomolecules in prebiotic simulation experiments using spark discharges and aqueous aerosols. These aerosols have been prepared using different sources of Fe(+2), such as FeS, FeCl(2) and FeCO(3), and other salts (alkaline and alkaline earth chlorides and sodium bicarbonate at pH = 5.8). In all these experiments, we observed the formation of some amino acids, carboxylic acids and heterocycles, involved in biological processes. An interesting consequence of the presence of soluble Fe(+2) was the formation of Prussian Blue, Fe(4)[Fe(CN)(6)](3), which has been suggested as a possible reservoir of HCN in the initial prebiotic conditions on the Earth.The authors have used the research facilities of Centro de Astrobiología and have been supported by Instituto Nacional de Técnica Aeroespacial "Esteban Terradas" and the project AYA2006-15648-C02-02 of the Ministerio of Educación y Ciencia (Spain).Peer reviewe

TWO SOURCES OF ZEOLITE AS SUBSTITUTES OF NITROGEN FERTILIZER FOR WHEAT (Triticum aestivum) PRODUCTION IN TLAXCALA, MEXICO

Nitrogen is the main nutrient added to the soil for wheat production, but its application increases production costs. Urea is the most used nitrogen fertilizer (NF) in Mexico, however only 10 to 60 % is absorbed by crops. To improve this efficiency, the use of slow-release fertilizers has been promoted, although their cost is high compared with traditional nitrogen sources. One alternative to increase the efficiency of NF is the use of minerals such as zeolite. One type of zeolite is the “clinoptiloliteâ€, an aluminum-silicate mineral. The objective of the study was to evaluate two sources of clinoptilolite (Chinobampo and Tehuacán). In four locations, six treatments were established: 1) 100 % NF; 2) 20 % zeoilte + 80 % NF; 3) 40 % zeolite + 60 % NF; 4) 60 % zeolite + 40 % NF; 5) 80 % zeolite + 20 % NF; and 6) 100 % zeolite. In treatments 2, 4 and 6 the seeds were mycorrhized before sowing. On average, treatment 3 yielded 2.9 ton ha-1, followed by treatment 2 with 2.6 ton ha-1, which yielded 2.3 and 3.0 ton ha-1 with zeolite Chinobampo and Tehuacán, respectively

Method for crystallisation from a solution

The present invention relates to a novel method and to a device for obtaining crystals from a substance, comprising: (i) preparing a saturated dissolution of the substance to be crystallized in a suitable solvent in a reaction vessel; (ii) generating an aerosol in the reaction vessel; (iii) crystallizing the substance; and (iv) recovering the crystals at the bottom of the reaction vessel. The method is especially suitable for crystallizing substances which are typically difficult to crystallize and can lead to a chiral amplification result.La presente invención relaciona a un nuevo método y a un dispositivo para obtener los cristales de una sustancia, comprendiendo: (i) preparando una disolución saturada de la sustancia que se cristalizará en un disolvente adecuado en un recipiente de reacción (ii) generar un aerosol en el recipiente de reacción (iii) cristalizar la sustancia y (iv) recuperando los cristales en el fondo del recipiente de reacción. El método es especialmente adecuado para cristalizar las sustancias que el son típicamente difícil cristalizar y el bote conducen a un resultado de la amplificación del quiral.Peer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patentes con informe sobre el estado de la técnic

Efecto de la estructura del suelo sobre el desarrollo radical del maíz con dos sistemas de labranza

La estructura del suelo (arreglo geométrico y topológico de los poros del suelo que se forman entre los agregados, y su estabilidad en tiempo y espacio) es una propiedad básica considerada como uno de los principales atributos de la calidad del suelo. En este estudio se analizaron dos sistemas de labranza de largo plazo bajo riego: tradicional (LT) y de conservación (LC), con especial énfasis en el comportamiento de propiedades como densidad aparente (ñb), la pendiente de la curva de retención de humedad en su punto de inflexión (S) y contenido de materia orgánica (MO), así como su relación con el sistema radical del maíz (Zea mays). Se efectuaron pruebas comparativas considerando algunos parámetros de suelo (ñb, MO, y S) y planta (biomasa, y longitud de raíz). Los resultados muestran que los parámetros ñb, MO y S utilizados para medir la calidad física del suelo, demostraron que los sistemas de labranza causan cambios en la estructura del mismo y por ende en su calidad. El sistema de LC propicia una mejor calidad e incrementa el contenido de MO en el suelo. Los valores de S son menores en LT, lo que indica que tiene menor capacidad de retener agua en comparación con LC. Se encontró una alta correlación entre S y longitud de raíz, significativa al agrupar los datos de acuerdo con el tipo de manejo. Por tanto, S se podría usar como un indicador para evaluar el impacto de las prácticas agrícolas sobre la calidad del suelo