Chemical synthesis and optical, structural, and surface characterization of InP-In2O3 quantum dots.

InP-In2O3 colloidal quantum dots (QDs) synthesized by a single-step chemical method without injection of hot precursors (one-pot) were investigated. Specifically, the effect of the tris(trimethylsilyl)phosphine, P(TMS)3, precursor concentration on the QDs properties was studied to effectively control the size and shape of the samples with a minimum size dispersion. The effect of the P(TMS)3 precursor concentration on the optical, structural, chemical surface, and electronic properties of InP-In2O3 QDs is discussed. The absorption spectra of InP-In2O3 colloids, obtained by both UV-Vis spectrophotometry and photoacoustic spectroscopy, showed a red-shift in the high-energy regime as the concentration of the P(TMS)3 increased. In addition, these results were used to determine the band-gap energy of the InP-In2O3 nanoparticles, which changed between 2.0 and 2.9 eV. This was confirmed by Photoluminescence spectroscopy, where a broad-band emission displayed from 2.0 to 2.9 eV is associated with the excitonic transition of the InP and In2O3 QDs. In2O3 and InP QDs with diameters ranging approximately from 8 to 10 nm and 6 to 9 nm were respectively found by HR-TEM. The formation of the InP and In2O3 phases was confirmed by X-ray Photoelectron Spectroscopy.

Growth Mechanism and Properties of Self-Assembled InN Nanocolumns on Al Covered Si(111) Substrates by PA-MBE.

Self-assembled InN nanocolumns were grown at low temperatures by plasma-assisted molecular beam epitaxy with a high crystalline quality. The self-assembling procedure was carried out on AlN/Al layers on Si(111) substrates avoiding the masking process. The Al interlayer on the Si(111) substrate prevented the formation of amorphous SiN. We found that the growth mechanism at 400 ∘ C of InN nanocolumns started by a layer-layer (2D) nucleation, followed by the growth of 3D islands. This growth mechanism promoted the nanocolumn formation without strain. The nanocolumnar growth proceeded with cylindrical and conical shapes with heights between 250 and 380 nm. Detailed high-resolution transmission electron microscopy analysis showed that the InN nanocolumns have a hexagonal crystalline structure, free of dislocation and other defects. The analysis of the phonon modes also allowed us to identify the hexagonal structure of the nanocolumns. In addition, the photoluminescence spectrum showed an energy transition of 0.72 eV at 20 K for the InN nanocolumns, confirmed by photoreflectance spectroscopy.

Properties of Particle Size Distribution from Milled White Nixtamalized Corn Kernels as a Function of Steeping Time.

This paper focuses on the particle size distribution (PSD) changes during nixtamalized corn kernels (NCK) as a function of the steeping time (ST). The process to obtain powder or corn flour from NCK was as follows: (i) the NCK with different STs were wet-milled in a stone mill, (ii) dehydrated by a Flash type dryer, and (iii) pulverized with a hammer mill and sieved with a 20 mesh. The powder was characterized by measuring the PSD percentage, calcium percentage (CP), peak viscosity at 90°C (PV), and crystallinity percentage (CP). The PSD of the powder as a function of ST was determined by sieving in Ro-TAP equipment. By sieving, five fractions of powder were obtained employing meshes 30, 40, 60, 80, and 100. The final weight of the PSD obtained from the sieving process follows a Gaussian profile with the maximum corresponding to the average particle obtained with mesh 60. The calcium percentage as a function of ST follows a behavior similar to the weight of the PSD. The study of crystallinity versus the mesh number shows that it decreases for smaller mesh number. A similar behavior is observed as steeping time increases, except around ST = 8 h where the gelatinization of starch is observed. The trend of increasing viscosity values of the powder samples occurs when increasing ST and decreasing particle size. The ST significantly changes the crystallinity and viscosity values of the powder and, in both cases, a minimum value is observed in the region 7-9 h. The experimental results show that the viscosity increases (decreases) if the particle size decreases (increases).

Male facial attractiveness and masculinity may provide sex- and culture-independent cues to semen quality.

Phenotype-linked fertility hypothesis (PLFH) predicts that male secondary sexual traits reveal honest information about male fertilization ability. However, PLFH has rarely been studied in humans. The aim of the present study was to test PLFH in humans and to investigate whether potential ability to select fertile partners is independent of sex or cultural background. We found that on the contrary to the hypothesis, facial masculinity was negatively associated with semen quality. As increased levels of testosterone have been demonstrated to impair sperm production, this finding may indicate a trade-off between investments in secondary sexual signalling (i.e. facial masculinity) and fertility or status-dependent differences in investments in semen quality. In both sexes and nationalities (Spanish and Colombian), ranked male facial attractiveness predicted male semen quality. However, Spanish males and females estimated facial images generally more attractive (gave higher ranks) than Colombian raters, and in both nationalities, males gave higher ranks than females. This suggests that male facial cues may provide culture- and sex-independent information about male fertility. However, our results also indicate that humans may be more sensitive to facial attractiveness cues within their own populations and also that males may generally overestimate the attractiveness of other men to females.

Effect of aracnotoxin from Latrodectus mactans on bovine sperm function: modulatory action of bovine oviduct cells and their secretions.

Latrodectus mactans' aracnotoxin (Atx) induces changes in sperm function that could be used as a co-adjuvant in male contraceptive barrier methods. This effect includes the suppression of intracellular reactive oxygen species (ROS), an event necessary for capacitation, chemotaxis and acrosome reaction (AR). The sperm that are not trapped by the barrier method can reach the oviduct before fertilisation and be exposed to the secretions of the oviducts. This study evaluated the effect of bovine tubal explants (TU) and conditioned media (CM) from the ampullar and isthmal regions on spermatozoa exposed to Atx. Thawed bovine sperm were incubated with Atx, TU and CM from the ampullar and isthmal regions for 4 h and then DNA integrity, intracellular ROS and lysophosphatidylcholine-induced AR were determined. Spermatozoa exposed to Atx and co-incubated with TU and CM for 4 h produced an increase in sperm DNA damage, a decrease in ROS production and a decrease in %AR, compared with the control. A similar result was obtained from the co-incubation of spermatozoa with Atx. In conclusion, the effect of Atx is not modified by tubal cells or their secretions and this opens the door to future studies to evaluate the application of synthetic peptides obtained from Atx as a co-adjuvant of contraceptive barrier methods.

Squamous cell carcinoma of the lip. A retrospective study of 146 patients.

BACKGROUND: Squamous cell carcinoma of the lip (SCCL) accounts for 90% of all tumours of the oral cavity. We present a series of 146 patients with SCCL studied in our hospital. OBJECTIVE: To evaluate and identify the primary tumour parameters related to local and lymph node recurrence. METHODS: We retrospectively analysed the clinical characteristics, surgical procedures and tumour recurrences of the 146 patients diagnosed with SCCL in Hospital Universitario Fundación Alcorcón (Spain). RESULTS: A total of 122 of the 146 patients (91.7%) showed tumour stage ≤ T1N0M0 at diagnosis, and 11 (8.3%) showed stage >T1N0M0. Local recurrences were observed in 11 of the 146 patients (7.5%), and five patients (3.4%) developed lymph node metastases during follow-up. Kaplan-Meier survival analysis showed an increased tumour size to imply a greater risk of local recurrence (P = 0.025). The probability of local recurrence over the 24 months of follow-up was 1% for tumour stages ≤ T1N0M0 and 20% for stages ≥ T1N0M0. There appears to be a greater tendency towards local relapse in male patients, in smokers, patients living in rural areas, in lower lip tumours and in those patients showing infiltration at physical exploration. Eleven patients (8%) died during follow-up, although in only two of them (18%), SCCL was the cause of death. CONCLUSION: The low tumour stage of our patients may explain the few local and lymph node disease recurrences seen in our study. We have shown tumour size to be directly related to the probability of local recurrence.

Rheology of the Pluronic P103/water system in a semidilute regime: evidence of nonequilibrium critical behavior.

The linear and nonlinear rheological behaviors of semidilute aqueous solutions of the amphiphile triblock polymer Pluronics P103 in water are reported here. For C(surf) < or = 20 wt%, micelles are spherical at temperatures lower than ca. 27 degrees C and grow with increasing temperature to form long polymer-like micelles. These polymer-like micelles exhibit strong viscoelasticity and a shear-banding region that shrinks as the cloud point is approached. Master time-temperature-concentration curves were obtained for the dynamic moduli using traditional shifting factors. In the nonlinear regime, P103 polymer-like micellar solutions follow the master dynamic phase diagram proposed by Berret and colleagues, in which the flow curves overlap in the low-shear-rate homogeneous flow region. Within the nonhomogeneous flow region (confirmed by flow birefringence and small-angle light-scattering measurements), oscillations and overshoots are detected at the inception of shear flow, and two main relaxation mechanisms are apparent after cessation of steady shear flow. Evidence for nonequilibrium critical behavior is presented, in which the order parameter is the difference of critical shear rates that limit the span of the plateau stress. Most of the steady-state and transient features of the nonlinear rheology of the P103 polymer-like micelles are reproduced with the Bautista-Manero-Puig (BMP) model, including the predictions of nonequilibrium critical behavior under flow.

Protective effect of fallopian tubal fluid against activated leucocyte-induced sperm DNA fragmentation: preliminary results.

The integrity of the paternal genome is of paramount importance in the initiation and maintenance of a viable pregnancy. Oxygen radicals (ROS) have been identified as one of the main factors responsible for the induction of sperm DNA damage. Spermatozoa are mainly protected against ROS-induced damage by seminal plasma. However, this protective effect disappears once spermatozoa enter the female genital tract. The fallopian tube mucosa may play a protective role against ROS-induced sperm damage. The main objective of this study was to determine whether human tubal explants and tubal fluid exert a protective effect on ROS-induced sperm DNA damage. Spermatozoa were exposed to tubal explants and/or tubal fluid in the presence of phorbol myristate acetate (PMA)-activated polymorphonuclear leucocytes or control medium and sperm DNA fragmentation was measured using the TdT-mediated dUTP-biotin nick end labelling (TUNEL) test. Exposure of human spermatozoa to PMA-activated leucocytes resulted in a 2-fold increase in sperm DNA fragmentation. Co-incubation of spermatozoa with tubal explants did not reduce this damage. However, pre-incubation of spermatozoa with tubal fluid resulted in a statistically significant reduction in sperm DNA fragmentation levels, comparable to those observed in control. In conclusion, tubal fluid appears to protect against activated leucocyte-induced sperm DNA fragmentation, thus preserving the integrity of the paternal genome.

Geographical differences in semen quality in a population of young healthy volunteers from the different regions of Spain.

Numerous studies have shown geographical differences in semen quality even within a given country. We have previously reported a low semen quality in volunteers from the province of Barcelona compared with the general population. The objective of this study was to determine the semen quality in a population of young healthy volunteers from the different regions of Spain. A total of 1239 volunteers between 18 and 30 years of age were enrolled. The parameters evaluated were semen volume, sperm concentration and progressive sperm motility. The results indicate that while there were no differences in semen volume or sperm motility, there were statistically significant differences in the rate of oligospermia in volunteers from the different regions studied. The prevalence of oligospermia was highest in Valencia (22.7%), Barcelona (22.7%) and Pais Vasco (18.7%), which are the regions of Spain with the highest degree of industrialisation for the last 50 years, and lowest in Galicia (8.5%) and Andalucía (13.7%), regions with a more recent industrial development. There were no differences in the rate of oligospermia as a function of age. These results support the hypothesis that exposure to environmental toxicants may affect the process of spermatogenesis leading to meiotic alterations, maturational arrest and oligospermia.

[Allergic contact dermatitis from lidocaine in ear drops]. / Eccema alérgico de contacto por lidocaína contenida en unas gotas óticas.

Lidocaine is one of the most widely used local anesthetics. It can be administered topically or parenterally. Allergic contact dermatitis from lidocaine is uncommon, but an increasing number of cases have been reported in recent years. We present the case of a 66-year-old man who presented with acute dermatitis on the pinna and left cheek after applying ear drops. Patch tests were positive for the product itself and for lidocaine in the ear drops, thereby confirming the diagnosis of contact dermatitis from lidocaine.

Semen quality in a population of volunteers from the province of Barcelona.

A prospective study was carried out on 1005 male volunteers residing in the province of Barcelona. Participants were asked to complete a questionnaire concerning their health status and lifestyle, and provided a semen sample for analysis. Sperm concentration and percentages of motile, and normal forms were evaluated. The effect of smoking, alcohol consumption, stress and previous disease on semen parameters was also evaluated. Normal parameters were found in 22% of volunteers and sperm counts and/or percentage motility below normal threshold values were found in 78%. Asthenozoospermia detected in 62% and oligozoospermia in 17% of volunteers. No statistically significant association was found between semen quality and age, with the exception of a decrease in semen volume (P = 0.04) and progressive motility (P = 0.01). No statistically significant differences in semen parameters were found between smokers and non-smokers or between males who consumed alcohol versus those that did not. However, stress had a negative effect on sperm concentration. In conclusion, the prevalence of normal semen parameters in the study population evaluated was markedly lower than that reported for the general population (60-70%). Since sperm concentration did not appear to decrease with age, the decrease observed in the last decades may be related to exposure to environmental toxicants during the fetal period, as previously suggested.

Delivery of a healthy baby following the transfer of embryos cryopreserved for 13 years.

Although embryos can theoretically be frozen for an unlimited period of time, there is still uncertainty about how long embryos can be cryopreserved without compromising pregnancy outcome. Following transfer of fresh embryos obtained after IVF, surplus embryos are usually frozen for personal use in later treatments. A 40-year-old woman was admitted to the centre's embryo adoption programme. She had a 7-year-old son, was diagnosed with ovarian factor infertility and her husband had secretory azoospermia. They underwent two cycles of IVF with donor spermatozoa and one cycle of donor intrauterine insemination that ended in spontaneous abortion. At this point, the couple was admitted to the embryo adoption programme. Six frozen embryos, obtained from a couple that had had a pregnancy through IVF at the centre and that had abandoned their surplus frozen embryos, were assigned to this patient. All six embryos were cryopreserved for 13 years. Of these, three were transferred and the patient became pregnant and delivered a healthy boy. Thanks to the embryo adoption programme, these embryos, rather than being left frozen for an indefinite period of time, were transferred to a couple that was willing to adopt them, resulting in the birth of a healthy newborn.

[Hypersensitivity reaction to systemic corticosteroids in a hemodialysis patients]. / Reacción de hipersensibilidad por corticoides sistémicos en una paciente en hemodiálisis.

Hypersensitivity reactions are a feared complication of hemodialysis considering their potential for a serious and eventually fatal course. This association could reflect a number of different exposures, including concomitant medications. Like this, systemic steroid-induced hypersensitivity reactions do occur, althought their incidence is extremely rare. A few reactions related to metylprednisolone have been reported in renal transplantation. The diagnosis could be confirmed by the patient history and performing skin testing, oral or parenteral challenge or by the evidence of specific IgE. We report on a 39-year-old woman undergoing dialysis therapy in whom severe bronchospasm was induced by corticosteroids. She has a positive systemic reaction on the oral steroid challenge test. A successful desensitization regimen for safe administration was achieved. The recognition of high-risk subjects and alternative therapeutic approach are critical, mainly in the management of patients while receiving corticosteroids or a renal allograft.

Effects of extracellular matrix on the morphology and behaviour of rabbit auricular chondrocytes in culture.

Isolated chondrocytes dedifferentiate to a fibroblast-like shape on plastic substrata and proliferate extensively, but rarely form nodules. However, when dissociation is not complete and some cartilage remnants are included in the culture, proliferation decreases and cells grow in a reticular pattern with numerous nodules, which occasionally form small cartilage-like fragments. In an attempt to reproduce this stable chondrogenic state, we added a cartilage protein extract, a sugar extract, and hyaluronan to the medium of previously dedifferentiated chondrocytes. When protein extract was added, many cartilaginous nodules appeared. Hyaluronan produced changes in cell phenotype and behaviour, but not nodule formation. Protein extract has positive effects on the differentiation of previously proliferated chondrocytes and permits nodule formation and the extensive production of type-II collagen. A comparison with incompletely dissociated chondrocyte cultures suggests that the presence of some living cells anchored to their natural extracellular matrix provides some important additional factors for the phenotypical stability of chondrocytes on plastic surfaces. In order to elucidate if it is possible that the incidence of apoptosis is related to the results, we also characterized the molecular traits of apoptosis.

Differential Behavior Between Isolated and Aggregated Rabbit Auricular Chondrocytes on Plastic Surfaces.

A knowledge of the behavior of chondrocytes in culture is relevant for tissue engineering. Chondrocytes dedifferentiate to a fibroblast-like phenotype on plastic surfaces. Dedifferentiation is reversible if these cells are then cultured in suspension. In this report a description is given of how when chondrocyte aggregates formed in suspension are next seeded on plastic, most of them attach as round or polygonal cells. This morphological differentiation, with synthesis of type II collagen, is stable for long culture periods. This simple method can be of use as a model for studies of chondrocyte behavior on plastic. The results indicate that in addition to culture conditions, such as cell isolation method or cell density, chondrocyte behavior on plastic depends on the presence of aggregates.

DNA fragmentation in human spermatozoa: significance in the diagnosis and treatment of infertility.

The integrity of the paternal genome is of paramount importance in the initiation and maintenance of a pregnancy in vivo and in vitro. The presence in the embryonic genome of chemical modifications at the level of DNA nucleotides and/or DNA strand breaks coming from the paternal genome (that have not been repaired by the oocyte after fertilization), is not compatible with normal embryo and fetal development. DNA fragmentation in human spermatozoa has been recently shown to be an important contributing factor to the etiology of unexplained infertility. In this review, the mechanisms responsible for DNA fragmentation in sperm, including defects in chromatin remodeling during the process of spermiogenesis, apoptosis and ROS-induced damage during sperm migration from the seminiferous tubules to the epididymis, are discussed. Also, the different methodologies used to determine DNA fragmentation in human sperm (with special emphasis on the SCSA test) and the applications of the SCSA test in the diagnosis and treatment of infertility, are presented. Finally, answers to common questions asked about the SCSA test are also included.

Photodynamic therapy with 5-aminolevulinic acid for recalcitrant familial benign pemphigus (Hailey-Hailey disease).

Familial benign pemphigus is a chronic, recurrent, autosomal dominant blistering disease that may significantly affect quality of life. Surgical methods are often needed to control flares in difficult cases. We describe the use of photodynamic therapy (PDT) with topical 5-aminolevulinic acid (ALA) followed by irradiation with incoherent light (ALA-PDT) in 2 patients with chronic, recalcitrant familial benign pemphigus.

Characterization of subsets of human spermatozoa at different stages of maturation: implications in the diagnosis and treatment of male infertility.

BACKGROUND: Reactive oxygen species (ROS)-induced damage of membrane phospholipids and DNA in human spermatozoa has been implicated in the pathogenesis of male infertility. In this study, variations in ROS production, DNA structure (as measured by the sperm chromatin structure assay) and lipid composition, were studied in human spermatozoa at different stages of maturation. METHODS: Sperm subsets were isolated by discontinuous density gradient centrifugation of semen samples obtained from healthy donors and from infertility patients. RESULTS: DNA damage and ROS production were highest in immature spermatozoa with cytoplasmic retention and abnormal head morphology, and lowest in mature spermatozoa. Docosahexaenoic acid and sterol content were highest in immature germ cells and immature spermatozoa, and lowest in mature spermatozoa. The relative proportion of ROS-producing immature spermatozoa in the sample was directly correlated with DNA damage in mature spermatozoa, and inversely correlated with the recovery of motile spermatozoa. There was no correlation between DNA damage and sperm morphology in mature spermatozoa. CONCLUSIONS: The high levels of ROS production and DNA damage observed in immature spermatozoa may be indicative of derangements in the regulation of spermiogenesis. DNA damage in mature spermatozoa may be the result of oxidative damage by ROS-producing immature spermatozoa during sperm migration from the seminiferous tubules to the epididymis.

Differential production of reactive oxygen species by subsets of human spermatozoa at different stages of maturation.

BACKGROUND: Reactive oxygen species (ROS)-mediated damage to human spermatozoa has been implicated in the pathogenesis of male infertility. Although ROS production by human spermatozoa has been extensively studied, the cell-to-cell variation in ROS production by spermatozoa at different stages of maturation has never been investigated. METHODS: In this study, we determined ROS production by subsets of human spermatozoa at different stages of maturation isolated by density gradient centrifugation of ejaculated spermatozoa obtained from healthy donors and from patients attending a clinic for infertility screening. RESULTS: Four different fractions were obtained. ROS production was highest in immature spermatozoa with abnormal head morphology and cytoplasmic retention and lowest in mature spermatozoa and immature germ cells (P < 0.01). ROS production was highest in immature spermatozoa from males with abnormal semen parameters compared with donors (P < 0.0001) or patients with normal semen parameters (P = 0.015). ROS production by immature spermatozoa was inversely correlated with the recovery of motile, mature spermatozoa in the high density fraction 4 (P = 0.01). CONCLUSIONS: The results of this study indicate that there is significant cell-to-cell variation in ROS production in subsets of spermatozoa at different stages of maturation and that oxidative damage of mature spermatozoa by ROS-producing immature spermatozoa during sperm migration from the seminiferous tubules to the epididymis may be an important cause of male infertility.