Molecular spins for quantum computation.

Spins in solids or in molecules possess discrete energy levels, and the associated quantum states can be tuned and coherently manipulated by means of external electromagnetic fields. Spins therefore provide one of the simplest platforms to encode a quantum bit (qubit), the elementary unit of future quantum computers. Performing any useful computation demands much more than realizing a robust qubit-one also needs a large number of qubits and a reliable manner with which to integrate them into a complex circuitry that can store and process information and implement quantum algorithms. This 'scalability' is arguably one of the challenges for which a chemistry-based bottom-up approach is best-suited. Molecules, being much more versatile than atoms, and yet microscopic, are the quantum objects with the highest capacity to form non-trivial ordered states at the nanoscale and to be replicated in large numbers using chemical tools.

Vanadyl dithiolate single molecule transistors: the next spintronic frontier?

On the road towards quantum devices, chemistry can offer elementary pieces with a built-in function, like [TbPc2]- which functions as a molecular transistor for nuclear spin detection. We argue that a large class of molecules have similar potential. In particular, we review the recent progress regarding highly coherent spin qubits based on vanadium dithiolate complexes. We propose their use as single molecule transistors to read and control a triple nuclear spin qubit, which could enable a low-current nuclear spin detection scheme by means of a spin valve effect.

Theoretical Evaluation of [VIV(α-C3S5)3]2- as Nuclear-Spin-Sensitive Single-Molecule Spin Transistor.

In a straightforward application of molecular nanospintronics to quantum computing, single-molecule spin transistors can be used to measure nuclear spin qubits. Conductance jumps accompany electronic spin flips at the so-called anticrossings between energy levels, which take place only at specific magnetic fields determined by the nuclear spin state. To date, the only molecular hardware employed for this technique has been the terbium(III) bis(phthalocyaninato) complex. Here we explore theoretically whether a similar behavior is expected for a highly stable molecular spin qubit, the vanadium tris-dithiolate complex [VIV(α-C3S5)3]2-. We consider such a molecule between two gold electrodes and determine the spin-dependent conductance. We verify that the transport channel in experimental conditions does not overlap with the occupied spin orbitals, indicating that the spin states may survive in the conduction regime. We validate the robustness of the theoretical methodology by studying two chemically related vanadium complexes and offer some criteria to guide the experiments.

Determining Key Local Vibrations in the Relaxation of Molecular Spin Qubits and Single-Molecule Magnets.

To design molecular spin qubits and nanomagnets operating at high temperatures, there is an urgent need to understand the relationship between vibrations and spin relaxation processes. Herein we develop a simple first-principles methodology to determine the modulation that vibrations exert on spin energy levels. This methodology is applied to [Cu(mnt)2]2- (mnt2- = 1,2-dicyanoethylene-1,2-dithiolate), a highly coherent complex. By theoretically identifying the most relevant vibrational modes, we are able to offer general strategies to chemically design more resilient magnetic molecules, where the energy of the spin states is not coupled to vibrations.

Lipids rich in ω-3 polyunsaturated fatty acids from microalgae.

Despite microalgae recently receiving enormous attention as a potential source of biodiesel, their use is still not feasible as an alternative to fossil fuels. Recently, interest in microalgae has focused on the production of bioactive compounds such as polyunsaturated fatty acids (PUFA), which provide microalgae a high added value. Several considerations need to be assessed for optimizing PUFA production from microalgae. Firstly, a microalgae species that produces high PUFA concentrations should be selected, such as Nannochloropsis gaditana, Isochrysis galbana, Phaeodactylum tricornutum, and Crypthecodinium cohnii, with marine species gaining more attention than do freshwater species. Closed cultivation processes, e.g., photobioreactors, are the most appropriate since temperature, pH, and nutrients can be controlled. An airlift column with LEDs or optical fibers to distribute photons into the culture media can be used at small scale to produce inoculum, while tubular and flat panels are used at commercial scale. Depending on the microalgae, a temperature range from 15 to 28 °C and a pH from 7 to 8 can be employed. Relevant conditions for PUFA production are medium light irradiances (50-300 µmol photons m(-2) s(-1)), air enriched with (0-1 % (v/v) CO2, as well as nitrogen and phosphorous limitation. For research purposes, the most appropriate medium for PUFA production is Bold's Basal, whereas mixotrophic cultivation using sucrose or glucose as the carbon source has been reported for industrial processes. For cell harvesting, the use of tangential flow membrane filtration or disk stack centrifugation is advisable at commercial scale. Current researches on PUFA extraction have focused on the use of organic solvents assisted with ultrasound or microwaves, supercritical fluids, and electroporation or are enzyme assisted. Commercial-scale extraction involves mainly physical methods such as bead mills and expeller presses. All these factors should be taken into account when choosing a PUFA production system, as discussed in this review.

Improving tibial component alignment in total knee arthroplasty.

PURPOSE: Tibia torsion may influence the accuracy of extramedullary instrumentations in total knee arthroplasty (TKA). This study assessed whether the effect of tibial torsion may be overcome using a surgical technique in which the extramedullary rod is aligned to reference points at the proximal tibia only. METHODS: A consecutive series of 94 knees that underwent TKA were analyzed. In the first 47 knees (group 1), a standard procedure for tibial component alignment was performed while in the second group of 47 knees, a modified surgical technique was used including the alignment of the extramedullary rod to the reference points at the proximal tibia only (group 2). Lower limb, femoral, and tibial component alignment were measured on postoperative long-leg radiographs. RESULTS: Femorotibial mechanical axes angles were similar in the two groups. Femoral component alignment also did not differ between the groups. A neutral alignment of the tibial component was achieved in 17 and 34 % of the knees in group 1 and group 2, respectively (p = 0.04). A malalignment of the tibial component >3° was found in 34 % of knees in group 1 compared with 4 % of those in group 2 (p = 0.0001). CONCLUSIONS: Coronal alignment of the tibial component may improve by setting the extramedullary rod in line with anatomical references in the proximal tibia only. This technique appears to bypass the influence of tibial torsion on the alignment of the extramedullary guide at the distal tibia. The clinical relevance of the study is that using this technique, the rate of malalignment of the tibial component may be reduced compared to a standard technique in which a fixed reference is used at the ankle joint.

Gd-based single-ion magnets with tunable magnetic anisotropy: molecular design of spin qubits.

We report ac susceptibility and continuous wave and pulsed EPR experiments performed on GdW10 and GdW30 polyoxometalate clusters, in which a Gd3+ ion is coordinated to different polyoxometalate moieties. Despite the isotropic character of gadolinium as a free ion, these molecules show slow magnetic relaxation at very low temperatures, characteristic of single molecule magnets. For T≲200 mK, the spin-lattice relaxation becomes dominated by pure quantum tunneling events, with rates that agree quantitatively with those predicted by the Prokof'ev and Stamp model [Phys. Rev. Lett. 80, 5794 (1998)]. The sign of the magnetic anisotropy, the energy level splittings, and the tunneling rates strongly depend on the molecular structure. We argue that GdW30 molecules are also promising spin qubits with a coherence figure of merit Q(M)≳50.

Lanthanoid single-ion magnets based on polyoxometalates with a 5-fold symmetry: the series [LnP5W30O110]12- (Ln3+ = Tb, Dy, Ho, Er, Tm, and Yb).

A robust, stable and processable family of mononuclear lanthanoid complexes based on polyoxometalates (POMs) that exhibit single-molecule magnetic behavior is described here. Preyssler polyanions of general formula [LnP(5)W(30)O(110)](12-) (Ln(3+) = Tb, Dy, Ho, Er, Tm, and Yb) have been characterized with static and dynamic magnetic measurements and heat capacity experiments. For the Dy and Ho derivatives, slow relaxation of the magnetization has been found. A simple interpretation of these properties is achieved by using crystal field theory.

Communication gaps in knowledge of freshwater fish biodiversity: implications for the management and conservation of Mexican biosphere reserves.

To detect differences in the information available on freshwater fish species found in Mexican biosphere reserves, the number of species considered in three sources of information: management programmes, Global Biodiversity Information Facility (GBIF) and the scientific literature were compared. Additionally, management actions for the reserves were evaluated. More than 55% of freshwater fish species registered for the reserves were found only in one of the three sources of information, while just 12% was shared among all the three. Fifteen threatened species were registered in GBIF and the scientific literature that were not found in management programmes. Although all the management programmes described conservation actions, none of them gave details about how they would be implemented. Lack of communication among the sources studied, unawareness of the existence of threatened species and the absence of detailed management actions hinder the development of adequate conservation strategies.

Aflatoxin M1 contamination in cow and buffalo milk samples from the North West Frontier Province (NWFP) and Punjab provinces of Pakistan.

A total of 178 milk samples (94 of buffalo and 84 of cow) were randomly taken from Punjab and the North West Frontier Province (NWFP) of Pakistan (n = 89 in each province) and analysed for the presence of aflatoxin M1 (AFM1) by HPLC-FLD. From Punjab about 46% of buffalo's and 49% of cow's milks were contaminated with AFM1 as compared with 52% and 51% for milk samples from NWFP, respectively. Overall, the mean AFM1 concentration was 0.046 µg kg(-1) with a maximum of 0.350 µg kg(-1). All samples complied with the Codex Alimentarius limit of 0.50 µg kg(-1) for AFM1 in milk, but 16.3% of samples exceeded the European Union maximum level of 0.05 µg kg(-1). Another set of 415 buffalo's and cow's milk samples (213 morning milks and 202 evening milks) were analysed. Statistical analysis revealed significant differences (p < 0.05) between mean AFM1 concentrations in milk during the morning (0.043 µg kg(-1)) and the evening (0.028 µg kg(-1)) lactation times.

Influence of agricultural practices on the contamination of maize by fumonisin mycotoxins.

The objective of the present work was to investigate the effect of different agricultural practices on the contamination of maize by fumonisin mycotoxins. Corn samples were collected from 16 maize fields located in Aragón (northeastern Spain) during the 2007 crop year. Corn samples were collected from each field five times at different maturation stages: F1, day 0 (milky corn); F2, day 15; F3, day 30 (yellow corn); F4, day 45; and F5, ripe corn at harvest. The agricultural practices evaluated were type of seed (conventional and transgenic), planting method (dry and wet planting), tillage system (plowing and minimum tillage), type of irrigation (flood and sprinkler), residue management of preceding crop (removal and burial), nitrogen fertilization level (kg N per ha), and harvest date. Mycotoxin analysis was carried out with the ROSA Fumonisin test, which measures both fumonisin B1 and B2 by lateral flow immunoassay. No fumonisins were detected in milky corn (F1 and F2 stages). Only one field had fumonisins in F3 yellow corn (1,037 microg/kg); this field was part of the only farm affected by borer insects. One-third of fields had fumonisins at the F4 stage (363 microg/kg), and 62.5% of the fields were positive for fumonisins at the F5 harvest stage (520 microg/kg). Wet planting and the removal of debris from the previous crop significantly lowered the risk of fumonisin in corn. The use of insect-resistant maize seeds tended to reduce fumonisin levels. However, higher levels of nitrogen fertilizer had a tendency to increase fumonisin levels in corn. Tillage system, type of irrigation, and harvest date had no clear effect on fumonisin levels.

Estimation of dietary intake of ochratoxin A from liquorice confectionery.

Ochratoxin A (OTA) was analyzed from 44 liquorice confectionery samples using immunoaffinity cleanup and liquid chromatography coupled with fluorescence detection. The presence of OTA was confirmed by methyl-ester derivatization. Liquorice confectionery samples were purchased from different retail outlets and supermarkets in Spain during 2007-2008, 16 of hard candies and 28 of soft candies. The incidence of OTA varied between 75% and 39% and mean ranged from 2.96 to 0.34 microg/kg for hard and soft candies, respectively. Assuming a total mean value of 1.29 microg OTA/kg sweet and a consumption of about 1.2g liquorice sweets per day, an OTA weekly uptake of 11 ng was obtained, or, based on a total body weight of 30 kg for a child consuming these sweets regularly, a weekly intake of 0.37 ng/kg body weight. This corresponds to 0.31% of the tolerable weekly intake (TWI) established by the European Food Safety Authority based of toxicological studies. Risk assessment in a worst case scenario (children high consumers and maximum content of OTA) represented 8.94% TWI by liquorice confectionery alone.

Linfoma testicular primario. Presentación de dos casos y revisión de la literatura / Primary testicular lymphoma. Report of two cases and bibliographic review

Objetivo: Comunicación de dos casos clínicos con diagnóstico de linfoma testicular primario y revisión de la literatura existente sobre esta patología. Métodos/ Resultados: Descripción de dos casos de linfoma testicular primario en dos varones de 69 y 61 años. En ambos casos su motivo de consulta fue un aumento de volumen testicular derecho. Tras practicar una orquiectomía inguinal se diagnóstico, en el primer caso, un linfoma difuso tipo T de células grandes y medianas, estadio I (E)-A, que tras seguir tratamiento con quimioterapia (R-CHOP) se mantiene en remisión a los tres años. En el segundo caso, el diagnóstico fue de linfoma difuso de células grandes tipo B, que tras recibir distintas pautas de quimioterapia, falleció a los 14 meses del diagnóstico. Conclusiones: El linfoma testicular es una entidad muy poco frecuente, a pesar de ser considerado el tumor testicular más común en mayores de 60 años. En su mayoría se trata de linfomas no Hodgkin difusos de grado intermedio alto de malignidad e inmunofenotipo B, considerando como excepcionales los de tipo T. Su pronóstico es pobre debido a su gran tendencia a la propagación sistémica. Su tratamiento se basa en orquiectomía, quimioterapia y radioterapia, si bien no existe una pauta estandarizada del mismo (AU)

Objective: We report two cases of primary testicular lymphoma and performed a bibliography review about this pathology. Methods/Results: We describe two cases of primary testicular lymphoma in two male patients 69 and 61 yr. old respectively. In both cases, reason for consultation was increase of the right testicular size. After inguinal orchyectomy the diagnosis for the first case was large and medium T cell diffuse lymphoma, stage I (E)-A; three years after chemotherapy (R-CHOP) the patient is in complete remission. In the second case, the diagnosis was diffuse large B-cell lymphoma, and after receiving various chemotherapy regimens died 14 months after diagnosis. Conclusions: Testicular lymphoma is a very rare entity, despite being considered the most common testicular tumor in patients over the age of 60 years. Most of them are non-Hodgkin diffuse, intermediate or high grade of malignancy , B-cell immunophenotype, being T-cell exceptional. Prognosis is poor due to their high tendency to systemic dissemination. The treatment is based on orchiectomy, chemotherapy and radiotherapy, although there is not a standardized regimen (AU)

[Maternal and perinatal data of hypospadic in a 25 year period]. / Análisis de los datos maternos y perinatales en pacientes con hipospadias en un periodo de 25 años.

OBJECTIVE: To analyze maternal and perinatal risk factors related to the onset and severity of hypospadias. MATERIAL AND METHODS: Data of 614 boys operated on hypospadias in our county during 25 years (1972-1998) has been studied. The patients were divided into 3 groups according the malformation severity: proximal, middle, and distal hypospadias. We use two periods, before and after 1980 to analyze the differences in risk factors along the time. RESULTS: There were 9% of proximal hypospadias, 13.6% middle hypospadias, and 77.5% distal hypospadias. We found statistical significance in several risk factors related to severe hypospadias: low birth weight, intrauterine growth restriction, preterm births, and associated malformations (p < 0.001). We did not find statistical significance with maternal age, toxic exposure, associated diseases, and x-ray exposure during pregnancy. After 1980, there were more severe hypospadias and less gestational age. CONCLUSIONS: Several events during pregnancy can contribute to the development of hypospadias in the fetus. In our experience, since 1980 there is a rise in the number and severity of hypospadias.

Ochratoxin A in liquorice as affected by processing methods.

A study of the effect of several processing methods on the concentration of ochratoxin A (OTA) in liquorice and derived products was carried out. The effect of the sorting, washing and peeling of fresh liquorice roots was investigated; as well as the production at a laboratory scale of liquorice extract and block liquorice from dry roots. Finally, the thermal stability of OTA was assessed. The OTA content was analysed by high-performance liquid chromatography-fluorescence and confirmed by methyl ester formation. The OTA level in liquorice extract was stable to heat treatment at 150 degrees C for 60 min. The OTA concentration was unaffected by sorting or washing, but it was much reduced by peeling (a 53.1% reduction). A great reduction in the OTA level was found during the production of liquorice extract (78.6%) and block liquorice (91.8%).

Análisis de los datos maternos y perinatales en pacientes con hipospadias en un periodo de 25 años / Maternal and perinatal data of hypospadic in a 25 year period

Introducción: El objetivo del estudio es definir los factores de riesgo materno-fetales que pueden influir en la aparición de hipospadias al nacimiento y en la gravedad del mismo. Material y Métodos: Se han recogido los datos de 614 recién nacidos con hipospadias operados en nuestra comunidad en los últimos 25 años (1972-1998). Para su estudio se han dividido en tres grupos de gravedad de la malformación (proximales, medios y distales) y en dos periodos de tiempo, antes y después de 1980, analizándolos en función de los posibles factores predisponentes. Resultados: El 9% presentaban hipospadias proximales, un 13,6% medios y un 77,5% distales. Se ha encontrado una relación estadísticamente significativa entre la gravedad del hipospadias y el bajo peso al nacimiento, retraso en el crecimiento intrauterino, prematuridad y existencia de malformaciones asociadas (p<0,001). No se ha encontrado significación estadística entre la gravedad del hipospadias y la edad materna, hábitos tóxicos, existencia de enfermedades o exposición a radiaciones en el embarazo. A partir del año 1980, los pacientes presentan hipospadias más severos y una edad gestacional menor. Conclusiones: Existen ciertos acontecimientos en el embarazo que pueden favorecer el desarrollo de hipospadias en el feto. Se esta produciendo un incremento en el número de pacientes con hipospadias y gravedad de estos desde 1980

Objective: To analyze maternal and perinatal risk factors related to the onset and severity of hypospadias. Material and Methods: Data of 614 boys operated on hypospadias in our county during 25 years (1972-1998) has been studied. The patients were divided into 3 groups according the malformation severity: proximal, middle, and distal hypospadias. We use two periods, before and after 1980 to analyze the differences in risk factors along the time. Results: There were 9% of proximal hypospadias, 13,6% middle hypospadias, and 77,5% distal hypospadias. We found statistical significance in several risk factors related to severe hypospadias: low birth weight, intrauterine growth restriction, preterm births, and associated malformations (p<0,001). We did not find statistical significance with maternal age, toxic exposure, associated diseases, and x-ray exposure during pregnancy. After 1980, there were more severe hypospadias and less gestational age. Conclusions: Several events during pregnancy can contribute to the development of hypospadias in the fetus. In our experience, since 1980 there is a rise in the number and severity of hypospadias

High levels of ochratoxin A in licorice and derived products.

The ochratoxin A (OTA) content of 30 samples of licorice root and derived products (licorice-confectionery, licorice block, and licorice extract) was analyzed by a standard HPLC-fluorescence technique and confirmed by methyl-ester formation. All analyzed samples of licorice and derived products were found to contain ochratoxin A, and some of them showed extremely high concentrations up to 252.8 ng/g of OTA. Highest levels of ochratoxin A were found in dry licorice root, averaging 63.6 ng/g, while mean contents in fresh licorice root were 9.2 ng/g. Licorice-confectionery (sweets) contained 3.8 ng/g of OTA. Ochratoxin A was also abundant in two licorice derivatives, liquid licorice extract (16.0 ng/g) and solid licorice block (39.5 ng/g). The ochratoxin levels found in licorice and derived products are higher than those reported in the literature for other food commodities. The experiments of OTA transfer into the tea beverages showed that almost 5% of the OTA present in dry licorice root is transferred to the corresponding decoction tea, whereas only 1% of OTA remains in infusion tea. The significance of the levels of ochratoxin A in licorice and its derivatives is discussed in the context of existing data on ochratoxin contamination in foods.