Static and dynamic electronic characterization of organic monolayers grafted on a silicon surface.

Organic layers chemically grafted on silicon offer excellent interfaces that may open up the way for new organic-inorganic hybrid nanoelectronic devices. However, technological achievements rely on the precise electronic characterization of such organic layers. We have prepared ordered grafted organic monolayers (GOMs) on Si(111), sometimes termed self-assembled monolayers (SAMs), by a hydrosilylation reaction with either a 7-carbon or an 11-carbon alkyl chain, with further modification to obtain amine-terminated surfaces. X-ray photoelectron spectroscopy (XPS) is used to determine the band bending (∼ 0.3 eV), and ultraviolet photoelectron spectroscopy (UPS) to measure the work function (∼ 3.4 eV) and the HOMO edge. Scanning tunneling microscopy (STM) confirms that the GOM surface is clean and smooth. Finally, conductive AFM is used to measure electron transport through the monolayer and to identify transition between the tunneling and the field emission regimes. These organic monolayers offer a promising alternative to silicon dioxide thin films for fabricating metal-insulator-semiconductor (MIS) junctions. We show that gold nanoparticles can be covalently attached to mimic metallic nano-electrodes and that the electrical quality of the GOMs is completely preserved in the process.

Relationship between food intake and cutaneous solar elastosis adjacent to basal cell carcinoma.

BACKGROUND/OBJECTIVE: Studies suggest that diet may influence in skin ageing and skin appearance. However, the effect of diet in the elastotic changes of dermis, which is the main histological sign of ageing, has not been studied previously. The objective was to investigate if the dietary habits influence the dermal elastosis observed in BCCs. MATERIALS AND METHODS: The 136 patients with facial BCCs, who underwent surgery, were interviewed to assess the consumption of fruit, vegetables, fat, red meat, coffee and tea. We reviewed 136 specimens of BCC to identify the presence of solar elastosis. We also analysed clinical variables such as gender, age, phototype and smoking. RESULTS: Severe solar elastosis was found in 22 patients (16%), middle reticular dermis in 37 (27 %) and 77 patients (57%) had abscence or light elastosis. Fat consumption was reported by most of participants from our sample, while fruit and tea consumption was less common. Intakes of fat, vegetables and coffee were not associated with the grade of elastosis whereas Vitamin E and C-rich fruits and tea were correlated with less risk of elastosis. Smokers showed higher grades of elastosis than non-smokers. CONCLUSION: Our study provides evidence that the presence of dermal elastosis and cutaneous ageing may be influenced by the type of food intake: Vitamin E and C-rich fruit and tea are positively associated with less elastosis.

Clinical differences in a multidisciplinary pediatric pain unit between primary and secondary chronic pain.

INTRODUCTION: Chronic pain affects an important part of the pediatric population in developed countries. secondary chronic pain (SCP) can have a well-defined medical cause, but primary chronic pain (PCP) can have an unknown etiology. In Spain, there is as yet no information on the clinical differences between patients treated in multidisciplinary units. METHODS: Retrospective analysis of the clinical records of patients seen in 2018 at the Children's Chronic Pain Unit in University La Paz Hospital. RESULTS: A total of 92 patients were included, (age between 3 and 19 years), with a mean age of 12.4 (SD = 4.1) years, mostly female (55%), with a mean duration of pain of 11.3 (SD = 10.4) months. A comparison of patients with PCP (n = 31) and SCP (n = 61) showed that both groups, on average, presented intense pain (X = 5.9; SD = 2.2; range = 0-10), with similar duration and functional repercussions, although PCP was less likely to be associated with neuropathic descriptors than SCP (p = 0.040), and was more extensive (p < 0.001). Both groups received similar treatment, based on rehabilitation, psychotherapy, invasive techniques and analgesic medication, although patients in the PCP group received less analgesic medication (gabapentinoids and opioids) than the SCP (p = 0.011). CONCLUSION: Patients treated in a multidisciplinary Child Pain Unit for PCP or SCP present a very similar clinical profile, though with differences in the number and type of analgesic drugs used. This shows the importance of etiologic diagnosis for adequate pharmacological treatment.

Assessment of incompletely excised basal cell carcinomas in six facial areas: influence of elastosis.

BACKGROUND: Incomplete excision of non-melanoma skin cancer is a clinical indicator of surgical care. With most basal cell carcinomas arising on the face and considering the cosmetic and functional structures involved, it is interesting to identify what are the areas within the face with more likelihood of incomplete excision and the factors implicated. The aim of this study was to identify those areas and possible predictive factors. Six anatomical regions were considered and studied selectively. METHOD: A monocentric study was performed reviewing all facial basal cell carcinomas excised at our center during 2010. Data were analyzed using SPSS software. RESULTS: 202 lesions from 202 subjects were studied. The percentage of incomplete excision was 17.07%. CONCLUSION: Lesions located in the orbitopalpebral and auricular areas and those with moderate to severe grade of associated elastosis are more likely to be incompletely excised. Wider surgical margins are observed in frontal, malar and labial areas which are distant from functional structures. The following tumor features were found to be a risk factor for incomplete resection: morpheic or superficial histology, large lesions (>20 mm) and thick lesions (>6 mm).

[Analysis of accidental falls and the integration in the chronicity programs of patients with amyotrophic lateral sclerosis]. / Análisis de las caídas accidentales y la integración en los programas de cronicidad de los pacientes con esclerosis lateral amiotrófica.

INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is the most common degenerative motor neuron disease. There is no curative treatment available, and these patients require multidisciplinary support to promote their comfort and quality of life. PATIENTS AND METHODS: Longitudinal descriptive study in patients registered in primary care (PC), Costa de Ponent-Barcelona Institut Catala de la Salut to analyse emergency hospital visits, use of support devices and their integration into the primary care chronicity program. Variables were sex, age and evolution time, emergency visits, patients with percutaneous gastrostomy (PEG), non-invasive or invasive ventilation (NIV/VI), integration in the primary care chronicity program. RESULTS: 81 patients, 49.4% male, mean age 65.6 years (±11.7), evolution time less than 2 years or equal to or greater than 2 years (42 and 58%, respectively). Of them, 47 (58.5%) made 107 consultations. The most frequent reasons for consultation were falls (26.8%), respiratory difficulties (23.3%), comorbidity (16.7%), eating problems (11%) and pain (10.2%) without differences by age or sex. Greater frequency (p < 0.001) was observed in patients with less than two years of evolution and significant increases in the use of NIV and PEG up to 51.9 and 35.8% respectively, as well as integration in primary care chronicity program of 61.7%. CONCLUSIONS: Accidental falls were the most frequent and potentially avoidable reason for hospital emergency visits in patients with ALS, especially in the first two years of the disease. Significant increases are detected in the use of support devices and in primary care chronicity program integration. It is necessary to increase home resources, especially in physiotherapy and occupational therapy.

TITLE: Análisis de las caídas accidentales y la integración en los programas de cronicidad de los pacientes con esclerosis lateral amiotrófica.Introducción. La esclerosis lateral amiotrófica (ELA) es la enfermedad degenerativa de las motoneuronas más frecuente. No dispone de tratamiento curativo y estos pacientes requieren un soporte multidisciplinar para favorecer su confort y calidad de vida. Pacientes y métodos. Estudio descriptivo longitudinal en pacientes registrados en atención primaria, Costa de Ponent-Barcelona, Institut Català de la Salut, para analizar las visitas urgentes hospitalarias, la utilización de dispositivos de soporte y su integración en el programa de atención a la cronicidad. Las variables fueron sexo, edad y tiempo de evolución, visitas urgentes, portadores de gastrostomía percutánea (PEG), ventilación no invasiva o invasiva (VNI/VI) e integración en el programa de atención a la cronicidad. Resultados. Se incluyó a 81 pacientes, un 49,4% varones, con una edad media de 65,6 años (±11,7), y un tiempo de evolución menor de 2 años o igual o mayor de 2 años (42 y 58%, respectivamente). De ellos, 47 (58,5%) realizaron 107 consultas. Los motivos de consulta más frecuentes fueron: caídas (26,8%), dificultades respiratorias (23,3%), comorbilidad (16,7%), problemas en la alimentación (11%) y dolor (10,2%), sin diferencias por edad o sexo. Se observó una mayor frecuentación (p menor de 0,001) en pacientes con menos de dos años de evolución e incrementos significativos en la utilización de la VNI y la PEG hasta el 51,9 y el 35,8%, respectivamente, así como integración en el programa de atención a la cronicidad del 61,7%. Conclusiones. El motivo más frecuente de consulta a urgencias hospitalarias de pacientes con ELA y potencialmente evitable fueron las caídas accidentales, especialmente en los primeros dos años de enfermedad. Se detectan incrementos significativos en la utilización de dispositivos de soporte y en la integración en el programa de atención a la cronicidad. Es necesario incrementar los recursos domiciliarios, especialmente en fisioterapia y terapia ocupacional.

Lipid levels in patients with lichen planus: a case-control study.

BACKGROUND: Cardiovascular risk factors have been assessed with some skin diseases such as alopecia and psoriasis. Recently, a case-control study found that lichen planus (LP) was associated with dyslipidaemia in a large series of patients. However, no data were presented about lipid values in patients and controls. OBJECTIVE: The objective of this case-control study was to evaluate lipid levels in men and women with lichen planus and in healthy controls, excluding lichenoid drug eruption and treatment for LP such as systemic corticosteroids, retinoid acid or methotrexate. PATIENTS AND METHODS: This case-control study included 160 patients, 80 with LP (40 men and 40 women) and 80 controls consecutively admitted to the outpatient clinic in Dermatology department of San Cecilio Hospital, Granada, Spain. RESULTS: Patients with LP presented higher significant triglycerides values (145.9 vs. 101.5 mg/dL P = 0.0007), total cholesterol values (197.7 vs. 178.4 mg/dL P = 0.001), LDL-C values (120.8 vs. 100.9 mg/dL P < 0.0001) and lower HDL-C values (55.3 vs. 61.9 mg/dL P = 0.004) vs. controls. Adjusted OR for dyslipidaemia in patients with LP was 3.03 (95% confidence interval: 1.49-6.17, P = 0.002). CONCLUSION: The results obtained in this study indicate an association between LP and dyslipidaemia. Lipid levels screening in men or women with LP may be useful to detect individuals at risk and start preventive treatment against the development of cardiovascular disease.

Domain wall conductivity in La-doped BiFeO3.

The transport physics of domain wall conductivity in La-doped bismuth ferrite (BiFeO3) has been probed using variable temperature conducting atomic force microscopy and piezoresponse force microscopy in samples with arrays of domain walls in the as-grown state. Nanoscale current measurements are investigated as a function of bias and temperature and are shown to be consistent with distinct electronic properties at the domain walls leading to changes in the observed local conductivity. Our observation is well described within a band picture of the observed electronic conduction. Finally, we demonstrate an additional degree of control of the wall conductivity through chemical doping with oxygen vacancies, thus influencing the local conductive state.

Hypertension and aldosterone levels in women with early-onset androgenetic alopecia.

BACKGROUND: Few studies have analysed the relationship between androgenetic alopecia (AGA) in women and cardiovascular disease. There is reported to be an elevated prevalence of hypertension among men with AGA, and it has been proposed that both phenomena may be explained by the presence of hyperaldosteronism. However, no data on blood pressure (BP) and aldosterone levels in women with AGA have been published to date. OBJECTIVES: The objective of this study was to evaluate aldosterone levels and the presence of systolic and diastolic hypertension in women with early-onset AGA and in healthy controls. PATIENTS AND METHODS: This case-control study included 40 women with AGA and 40 healthy controls from the Department of Dermatology of San Cecilio Hospital, Granada, Spain. RESULTS: Patients with AGA showed significantly higher systolic BP values (139.43 vs. 107.80 mmHg; P < 0.0001), diastolic BP values (87.65 vs. 67.48 mmHg; P < 0.0001) and aldosterone levels (249.55 vs. 155.14 pg mL(-1); P = 0.002) vs. controls, respectively. A positive correlation between aldosterone levels and systolic and diastolic BP values is described. CONCLUSIONS: A higher prevalence of hypertension in women with AGA has been found. The elevated aldosterone values in these patients may contribute, alongside other mechanisms, to the development of AGA and may also explain the higher prevalence of hypertension. BP screening of women with AGA will permit earlier diagnosis of an unsuspected hypertension and initiation of appropriate treatment.

[Male androgenetic alopecia and cardiovascular risk factors: A case-control study]. / Alopecia androgénica masculina y factores de riesgo cardiovascular: estudio de casos y controles.

BACKGROUND AND OBJECTIVES: The relationship between androgenetic alopecia and cardiovascular disease has been studied by some authors in the past, although the results of epidemiological studies have been variable. The objective of this study was to determine the prevalence of metabolic syndrome and carotid arteriosclerosis in patients with early-onset androgenetic alopecia. PATIENTS AND METHODS: Seventy men were studied, 35 with diagnosis of early-onset (before 35 years of age) androgenetic alopecia and 35 control subjects who consulted for other skin conditions. In both groups, the criteria for metabolic syndrome according to the Adult Treatment Panel-III were studied (obesity, triglycerides, high-density lipoprotein cholesterol, systolic and diastolic blood pressure, and blood glucose), presence of atheromatous plaques, and carotid intima-media thickness using Doppler ultrasonography. Other cardiovascular risk factors, hormones, and acute-phase reactants were also analyzed. RESULTS: Criteria for metabolic syndrome were met by 57.1% of the patients with androgenetic alopecia compared to 14.3% of the controls (P<0001). Thirty-four percent of the patients with androgenetic alopecia had atheromatous plaques compared to 8.6% of the controls (P=.018). In an independent correlation analysis, abdominal obesity, systolic blood pressure, triglycerides, and blood glucose levels were significantly greater among patients with androgenetic alopecia. Testosterone and sex hormone binding globulin levels were similar in the 2 groups whereas insulin and aldosterone levels were higher in patients with androgenetic alopecia (P<05). CONCLUSIONS: The high frequency of metabolic syndrome and carotid atheromatous plaques in patients with androgenetic alopecia suggests cardiovascular screening should be done to enable early detection of individuals at risk and initiation of preventive treatment before cardiovascular disease becomes established.

Elevated aldosterone levels in patients with androgenetic alopecia.

BACKGROUND: There is reported to be an elevated prevalence of hypertension among patients with androgenetic alopecia (AGA), and it has been proposed that both phenomena may be explained by the presence of hyperaldosteronism. However, no data on aldosterone levels in patients with AGA have been published to date. OBJECTIVES: The objective of this pilot study was to evaluate aldosterone levels and the presence of hypertension in patients with AGA and in healthy controls. METHODS: This case-control study included 40 patients with AGA and 40 healthy controls from the Dermatology Department of San Cecilio Hospital, Granada, Spain. RESULTS: Patients with AGA showed significantly higher systolic blood pressure values (136.23 vs. 124.10 mmHg, P = 0.01) and aldosterone levels (197.35 vs. 133.71 pg mL(-1), P = 0.007) vs. controls. CONCLUSION: The elevated aldosterone values in these patients may contribute, together with other mechanisms, to the development of AGA and may also explain the higher prevalence of hypertension. Blood pressure screening of patients with AGA will permit earlier diagnosis of an unknown hypertension and initiation of appropriate treatment.

Nanocatalysis by the tip of a scanning tunneling microscope operating inside a reactor cell.

The platinum-rhodium tip of a scanning tunneling microscope that operates inside of an atmospheric-pressure chemical reactor cell has been used to locally rehydrogenate carbonaceous fragments deposited on the (111) surface of platinum. The carbon fragments were produced by partial dehydrogenation of propylene. The reactant gas environment inside the cell consisted of pure H(2) or a 1:9 mixture of CH(3)CHCH(2) and H(2) at 300 kelvin. The platinum-rhodium tip acted as a catalyst after activation by short voltage pulses. In this active state, the clusters in the area scanned by the tip were reacted away with very high spatial resolution.

Imaging the condensation and evaporation of molecularly thin films of water with nanometer resolution.

The polarization force between an electrically charged atomic force microscope tip and a substrate has been used to follow the processes of condensation and evaporation of a monolayer of water on mica at room temperature. Condensation proceeds in two distinct structural phases. Up to about 25 percent humidity, the water film grows by forming two-dimensional clusters of less than a few 1000 angstroms in diameter. Above about 25 percent humidity, a second phase grows, forming large two-dimensional islands with geometrical shapes in epitaxial relation with the underlaying mica lattice. The growth of this second water phase is completed when the humidity reaches about 45 percent. The reverse process of evaporation has also been imaged.

Total alignment of calcite at acidic polydiacetylene films: cooperativity at the organic-inorganic interface.

Biological matrices can direct the absolute alignment of inorganic crystals such as calcite. Cooperative effects at an organic-inorganic interface resulted in similar co-alignment of calcite at polymeric Langmuir-Schaefer films of 10,12-pentacosadiynoic acid (p-PDA). The films nucleated calcite at the (012) face, and the crystals were co-aligned with respect to the polymer's conjugated backbone. At the same time, the p-PDA alkyl side chains reorganized to optimize the stereochemical fit to the calcite structure, as visualized by changes in the optical spectrum of the polymer. These results indicate the kinds of interactions that may occur in biological systems where large arrays of crystals are co-aligned.

Direct observation of native DNA structures with the scanning tunneling microscope.

Uncoated double-stranded DNA dissolved in a salt solution was deposited on graphite and imaged in air with the scanning tunneling microscope (STM). The resolution was such that the major and minor grooves could be distinguished. The pitch of the helix varied between 27 and 63 angstroms in the images obtained. Thus the STM can be useful for structural studies of a variety of uncoated and isolated biomolecules.

Noncontact to contact tunneling microscopy in self-assembled monolayers of alkylthiols on gold.

The mechanical interaction between a scanning tunneling microscopy (STM) probe and hexadecane (C16) alkylthiol molecules in a self-assembled monolayer was investigated by sensing the force during constant current mode STM imaging. The force regime changed from attractive to repulsive over the insulating molecule islands under feedback control of the current. The repulsive force on the molecule was strongly dependent on the setpoint value of the current during STM operation. In our experiments, the threshold for contact was found at a tunneling current of 1 pA when the sample bias is 2 V. At higher current, the apparent height of molecular islands changed logarithmically with current. In addition, the current as a function of applied load revealed a stepwise increase, indicative of discrete molecular tilting events. A tunneling decay constant beta of =0.53+/-0.02 A(-1) was obtained based on the measurement of the height of molecules and the tunneling current.

The structure of mixed H2O-OH monolayer films on Ru(0001).

Scanning tunneling microscopy (STM) and x-ray absorption spectroscopy (XAS) have been used to study the structures produced by water on Ru(0001) at temperatures above 140 K. It was found that while undissociated water layers are metastable below 140 K, heating above this temperature produces drastic transformations, whereby a fraction of the water molecules partially dissociate and form mixed H(2)O-OH structures. X-ray photoelectron spectroscopy and XAS revealed the presence of hydroxyl groups with their O-H bond essentially parallel to the surface. STM images show that the mixed H(2)O-OH structures consist of long narrow stripes aligned with the three crystallographic directions perpendicular to the close-packed atomic rows of the Ru(0001) substrate. The internal structure of the stripes is a honeycomb network of H-bonded water and hydroxyl species. We found that the metastable low temperature molecular phase can also be converted to a mixed H(2)O-OH phase through excitation by the tunneling electrons when their energy is 0.5 eV or higher above the Fermi level. Structural models based on the STM images were used for density functional theory optimizations of the stripe geometry. The optimized geometry was then utilized to calculate STM images for comparison with the experiment.

A Model for the Characterization of the Polarizability of Thin Films Independently of the Thickness of the Film.

The dielectric properties of thin films can be modified relative to the bulk material because the interaction between film and substrate influences the mobility of the atoms or molecules in the first layers. Here we show that a strong scale effect occurs in nanometer size octadecylammine thin films. This effect is attributed to the different distribution of molecules depending on the size of the film. To accurately describe this effect, we have developed a model which is a reinterpretation of the linearized Thomas-Fermi approximation. Within this model, we have been able to characterize the polarizability of thin films independently of the thickness of the film.

Induced water condensation and bridge formation by electric fields in atomic force microscopy.

We present an analytical model that explains how, in humid environments, the electric field near a sharp tip enhances the formation of water menisci and bridges between the tip and a sample. The predictions of the model are compared with experimental measurements of the critical distance where the field strength causes bridge formation.

A New Data Analysis System to Quantify Associations between Biochemical Parameters of Chronic Kidney Disease-Mineral Bone Disease.

BACKGROUND: In hemodialysis patients, deviations from KDIGO recommended values of individual parameters, phosphate, calcium or parathyroid hormone (PTH), are associated with increased mortality. However, it is widely accepted that these parameters are not regulated independently of each other and that therapy aimed to correct one parameter often modifies the others. The aim of the present study is to quantify the degree of association between parameters of chronic kidney disease and mineral bone disease (CKD-MBD). METHODS: Data was extracted from a cohort of 1758 adult HD patients between January 2000 and June 2013 obtaining a total of 46.141 records (10 year follow-up). We used an advanced data analysis system called Random Forest (RF) which is based on self-learning procedure with similar axioms to those utilized for the development of artificial intelligence. This new approach is particularly useful when the variables analyzed are closely dependent to each other. RESULTS: The analysis revealed a strong association between PTH and phosphate that was superior to that of PTH and Calcium. The classical linear regression analysis between PTH and phosphate shows a correlation coefficient is 0.27, p<0.001, the possibility to predict PTH changes from phosphate modification is marginal. Alternatively, RF assumes that changes in phosphate will cause modifications in other associated variables (calcium and others) that may also affect PTH values. Using RF the correlation coefficient between changes in serum PTH and phosphate is 0.77, p<0.001; thus, the power of prediction is markedly increased. The effect of therapy on biochemical variables was also analyzed using this RF. CONCLUSION: Our results suggest that the analysis of the complex interactions between mineral metabolism parameters in CKD-MBD may demand a more advanced data analysis system such as RF.