Few layers graphene as thermally activated optical modulator in the visible-near IR spectral range.

We report the temperature modulation of the optical transmittance of a few layers of graphene (FLG). The FLG was heated either by the Joule effect of the current flowing between coplanar electrodes or by the absorption of a continuous-wave 532 nm laser. The optical signals used to evaluate the modulation of the FLG were at 633, 975, and 1550 nm; the last wavelengths are commonly used in optical communications. We also evaluated the effect of the substrate on the modulation effect by comparing the performance of a freely suspended FLG sample with one mounted on a glass substrate. Our results show that the modulation of the optical transmittance of FLG can be from millihertz to kilohertz.

[Small fiber neuropathy as a possible cause for chronic pruritus]. / Kleinfaserneuropathie als mögliche Ursache für chronischen Pruritus.

BACKGROUND: Small fiber neuropathy arises from injury of small C and Aδ fibers and leads to pruritus as well as positive (pain, burning, tingling or stinging sensation) and negative neurological (numbness) symptoms. OBJECTIVES: To give an overview on small fiber neuropathy as a cause for chronic pruritus, the diagnostic approach to this condition, and therapeutic options. MATERIALS AND METHODS: A literature search using the terms "small fiber neuropathy", "pruritus", "itch", and "pain" was performed. RESULTS: Small fiber neuropathy is often associated with systemic diseases. However, it may occur without an underlying cause (idiopathic small fiber neuropathy). To identify small fiber neuropathy as the causal agent of pruritus, a detailed clinical history is essential. By measuring the intraepidermal nerve fiber density from skin biopsies at the sural nerve supplied region (lateral lower leg), the neurological impairment can be quantified. Often, dysfunction of a nerve fiber occurs after morphological changes ensue. Quantitative sensory testing allows the study of impaired function of these small fibers. Therapeutically, it is important to treat the underlying cause of the neuropathy. A symptomatic approach should be taken into account, when the cause cannot be treated. Topical capsaicin, as well as anticonvulsants and/or antidepressants, have been used with good results. CONCLUSION: Due to chronification processes, pruritus may persist even after treatment of the underlying cause. Therefore, early identification of small fiber neuropathy and immediate treatment of the cause is crucial for the success of the treatment.

Agreeableness and Self-Consciousness as Predictors of Induced Scratching and Itch in Patients with Psoriasis.

BACKGROUND: Psoriasis (PS) is a frequent skin disease accompanied by itch, a symptom that has been shown to be related to depression and self-consciousness. PS patients describe themselves as more agreeable than healthy controls (HC), a trait that might be protective against impulsive scratching. PURPOSE: This study is the first to analyze the relationship between agreeableness and induced scratching and between depression, self-consciousness, and induced itch in PS patients. METHODS: Twenty-four PS patients and 24 HC were shown two videos: an itch-inducing experimental video (EV) and a non-itch-inducing control video (CV). Induced itch/scratching was determined by calculating the difference in itch intensity/number of scratch movements between EV and CV. Validated questionnaires were used to measure agreeableness, depression, and self-consciousness. RESULTS: In accordance with our hypothesis, in PS patients, public self-consciousness was significantly positively associated with induced itch (r = 0.564; p < 0.001), and agreeableness was significantly negatively associated with induced scratching (r = -0.444; p < 0.05). In HC, the relationship between public self-consciousness and induced itch and between agreeableness and induced scratching were positive, but not significant. CONCLUSIONS: This study showed distinct findings for PS patients and HC regarding the relationship between agreeableness and induced scratching. The relationship between public self-consciousness and induced itch was positive in both groups. The distinct finding regarding agreeableness supports the idea that scoring low on this scale might be a protective factor for scratching in PS patients. Future research should investigate mediating factors of the outlined relationships.

Structural, chemical and mechanical study of TiAlV film on UHMWPE produced by DC magnetron sputtering.

Ultra High Molecular Weight Polyethylene (UHMWPE), with a semi-trapezoidal topography, and glass samples were coated with a TiAlV film using magnetron sputtering in order to study its structure, chemical composition and the adhesion film properties on the polymer surfaces. The magnetron sputtering is a PVD technique that depending on the deposited parameter produces a coating with structural, chemical and specific topographic characteristics that increase the electrical, mechanical, optical and biological surface properties of the organic compounds. The quantities of Vanadium (V) and Aluminum (Al) were similar to that of Ti64 alloy. The metallic film obtained presents α-Ti phase structure with a (200) preferential orientation. The TiAlV film on polymeric surfaces with semi-trapezoidal topography exhibit irregularities and uncoated zones but on the glass, the metallic coating was smooth and continuous. The scratch tests were carried out using an incremental load configuration with a Tribotechnic scratch tester equipment. The metallic film decreased the viscoelastic recovering of the polymeric surface but increased the load capacity. The metallic film did not present complete delamination but fractures and small zones of coating detachment were observed on all the scratch tracks.

Cylindrical hot refractory anode vacuum arc (CHRAVA).

We present a study of a novel vacuum arc deposition system composed of a water-cooled aluminum cathode and a hot refractory anode. The plasma of the arc system was diagnosed using a cylindrical electrostatic probe. It was found that the mean electron temperature was ∼2 eV, the plasma density could be varied in the range of 0.5-6 × 1016 m-3, and the ion flux was between 0.06 and 0.35 A m-2. Optical emission spectroscopy measurements showed the presence of emission lines corresponding to Al i and Al ii. The characterization of the coatings showed that the deposition rate varied from 0.8 to 4 nm/s and the surface roughness (Ra) of the films was as low as 25 nm. We demonstrated that it was possible to deposit films with low macroparticle densities, overcoming the principal disadvantage of the vacuum arc process. Measurements of the arc voltage and current were performed as a function of time and the applied magnetic field. The anode temperature was measured using a pyrometer through a ZnS window as a function of time and arc current, and the maximum value was 1800 °C with heating rates of up to 110 °C/s.

Major cat and dog allergens share IgE epitopes.

BACKGROUND: Patients allergic to cats and dogs frequently display IgE reactivity against allergens from different animals, suggesting a cross-sensitization to common allergenic determinants. Although albumins have been recognized as relevant cross-reactive allergens, little is known regarding cross-reactive epitopes of the major cat and dog allergens. OBJECTIVE: In this study, sera from patients allergic to cats and/or dogs were used to investigate the presence of common IgE epitopes among the major cat and dog allergens. METHODS: The IgE reactivity profile of 109 patients who were allergic to allergens from several species of animals was determined with nitrocellulose-blotted cat and dog allergens. Sera from patients who were strongly allergic to the major cat and dog allergens were tested for the presence of cross-reactive IgE antibodies by one-dimensional and two-dimensional immunoblot inhibition experiments and by quantitative measurements obtained with the CAP-FEIA system (Pharmacia). RESULTS: Sixty-eight of 109 patients with animal allergy showed IgE reactivity to cat allergens and dog allergens. Sera from patients with both cat and dog allergy detected allergens of similar molecular weight in nitrocellulose-blotted cat and dog hair/dander extracts. Common, as well as species-restricted, IgE epitopes of the major cat and dog allergens could be demonstrated by IgE inhibition studies. CONCLUSION: Shared IgE epitopes of the major cat and dog allergens may provide an explanation for the clinical observation that allergies to cats and dogs are frequently associated.

Characterization of allergens from deer: cross-reactivity with allergens from cow dander.

BACKGROUND: Animal hair/dander proteins frequently cause Type I hypersensitivities. Species-specific and broadly cross-reacting allergens have been characterized in the past. METHODS: Sera from eight individuals suffering from symptoms due to exposure to deer and deer-derived products were investigated by immunoblotting. Extracts from deer, dog, cat, horse, rabbit and cow, respectively, were tested for IgE-binding. To reveal cross-reactivities patients' sera were preadsorbed with these extracts prior to testing with deer extract. RESULTS: Deer allergens with the molecular mass of 22 and 25 kD (major allergens), as well as 60 kD were identified. The 22 and 25 kD allergens are cross-reactive with the corresponding cow allergens. CONCLUSION: Deer allergy is a rare sensitization mainly affecting persons exposed to deer, who displayed an atopic disposition. From our results it can be assumed that this hypersensitivity is partly associated with allergy to cow dander.

IgE cross-reactivities against albumins in patients allergic to animals.

BACKGROUND: Type I allergic symptoms and severe asthma in particular are frequently caused by animal hair/dander proteins, among which albumins are possible cross-sensitizing allergenic components. METHODS: The significance and degree of IgE-cross-reactivities against various albumins were studied in a representative number (n = 200) of patients allergic to animals with hair/dander extracts, purified albumins from different animals, and a recombinant dog albumin fragment expressed in lysogenic Escherichia coli Y1089 and purified as a beta-galactosidase fusion protein. RESULTS: Despite a high degree of sequence homology among different albumins, a remarkable variability of IgE cross-reactivities was observed, indicating that some patients were sensitized preferentially against certain albumins. Most of the patients allergic to albumins, however, reacted to dog, cat, and horse albumin, which also bound a high percentage of albumin-specific IgE. CONCLUSION: The purified recombinant dog albumin fragment, representing 265 amino acids of the mature protein, bound IgE from all 15 patients allergic to albumin tested suggesting its potential usefulness for diagnosis and perhaps therapy.

Molecular characterization of dog albumin as a cross-reactive allergen.

Indoor allergens comprise a group of allergenic proteins that are commonly derived from house dust mite and cat and dog dander. In addition to the two major dog allergens (molecular weights: 19 and 23 kd), dog albumin represents an important allergen for up to 35% of patients who are allergic to dogs. In IgE immunoblot inhibition studies and histamine release tests it has been demonstrated that patients who react to dog albumin exhibit IgE reactivity with purified albumins from cat, mouse, chicken, and rat. The proportion of dog-specific IgE directed against dog albumin was determined for patients allergic to dog albumin, and it ranges from 70% to 90%. By IgE immunoscreening of a lambda gt11 expression library from a dog salivary gland, we identified a number of reactive complementary DNA clones. All patients with IgE reactivity against natural dog albumin displayed IgE reactivity to the beta-galactosidase fusion protein encoded by clone 54c, which was therefore assumed to contain major IgE epitopes of dog albumin. The deduced amino acid sequence of clone 54c was compared with the Swiss-Prot library, and significant sequence homologies were found with albumins from different species (human: 82.6%, pig: 81.8%, cattle: 77.3%, sheep: 78.8%, mouse: 75.8%, and rat: 76.2%). Several other IgE-positive clones hybridized with oligonucleotides that were prepared according to this sequence. Partial complementary DNA coding for dog albumin fragments may be considered a useful tool for further characterization of major IgE epitopes of dog albumin.