Polychromatic emission in a wide energy range from InP-InAs-InP multi-shell nanowires.

InP-InAs-InP multi-shell nanowires (NWs) were grown in the wurtzite (WZ) or zincblende (ZB) crystal phase and their photoluminescence (PL) properties were investigated at low temperature (≈6 K) for different measurement geometries. PL emissions from the NWs were carefully studied in a wide energy range from 0.7 to 1.6 eV. The different features observed in the PL spectra for increasing energies are attributed to four distinct emitting domains of these nano-heterostructures: the InAs island (axially grown), the thin InAs capping shell (radially grown), the crystal-phase quantum disks arising from the coexistence of InP ZB and WZ segments in the same NW, and the InP portions of the NW. These results provide a useful frame for the rational implementation of InP-InAs-InP multi-shell NWs containing various quantum confined domains as polychromatic optically active components in nanodevices for quantum information and communication technologies.

Deposition of metallic silver coatings by Aerosol Assisted MOCVD using two new silver ß-diketonate adduct metalorganic precursors.

This work reports two new silver metalorganic precursors for the chemical vapor deposition of Ag metallic coatings. Both precursors are based on ß-diketonate adducts, namely, Ag(hfac)(L) (H-hfac = 1,1,1,5,5,5-hexafluoro-2,4-pentanedione), where L is 1,10-phenanthroline (phen) or 2,5,8,11-tetraoxadodecane (triglyme). Using these ligands, the designed precursors have better solubility in alcoholic solvents and are less toxic and costly than previously reported ones. The new precursors have been characterized and their crystallographic structure solved. With the new triglyme precursor, [Ag(triglyme)2]+[Ag(hfac)2]-, pure metallic Ag coatings made of Ag nanoparticles about 20 nm in diameter were succesfully deposited on glass and Si substrates using Aerosol Assisted Metalorganic CVD (AA-CVD).

Heterogeneous nucleation of catalyst-free InAs nanowires on silicon.

We report on the heterogeneous nucleation of catalyst-free InAs nanowires on Si(111) substrates by chemical beam epitaxy. We show that nanowire nucleation is enhanced by sputtering the silicon substrate with energetic particles. We argue that particle bombardment introduces lattice defects on the silicon surface that serve as preferential nucleation sites. The formation of these nucleation sites can be controlled by the sputtering parameters, allowing the control of nanowire density in a wide range. Nanowire nucleation is accompanied by unwanted parasitic islands, but careful choice of annealing and growth temperature allows us to strongly reduce the relative density of these islands and to realize samples with high nanowire yield.

Objective estimation of body condition score by modeling cow body shape from digital images.

Body condition score (BCS) is considered an important tool for management of dairy cattle. The feasibility of estimating the BCS from digital images has been demonstrated in recent work. Regression machines have been successfully employed for automatic BCS estimation, taking into account information of the overall shape or information extracted on anatomical points of the shape. Despite the progress in this research area, such studies have not addressed the problem of modeling the shape of cows to build a robust descriptor for automatic BCS estimation. Moreover, a benchmark data set of images meant as a point of reference for quantitative evaluation and comparison of different automatic estimation methods for BCS is lacking. The main objective of this study was to develop a technique that was able to describe the body shape of cows in a reconstructive way. Images, used to build a benchmark data set for developing an automatic system for BCS, were taken using a camera placed above an exit gate from the milking robot. The camera was positioned at 3 m from the ground and in such a position to capture images of the rear, dorsal pelvic, and loin area of cows. The BCS of each cow was estimated on site by 2 technicians and associated to the cow images. The benchmark data set contained 286 images with associated BCS, anatomical points, and shapes. It was used for quantitative evaluation. A set of example cow body shapes was created. Linear and polynomial kernel principal component analysis was used to reconstruct shapes of cows using a linear combination of basic shapes constructed from the example database. In this manner, a cow's body shape was described by considering her variability from the average shape. The method produced a compact description of the shape to be used for automatic estimation of BCS. Model validation showed that the polynomial model proposed in this study performs better (error=0.31) than other state-of-the-art methods in estimating BCS even at the extreme values of BCS scale.

Enhanced iodine concentrating capacity by the mammary gland in iodine deficient lactating women of an endemic goiter region in Sicily.

Iodine balance during pregnancy and lactation was investigated by measuring iodine concentration in the urine of 11 pregnant women, born and living in a moderately iodine deficient endemic goiter area in Northeastern Sicily, collected during the last week of pregnancy, and between the 5th and 7th day after delivery, and in their milk sampled simultaneously with the urine of their newborns. The results were compared with those obtained on similar samples from 16 euthyroid age-matched nongoitrous women and their offspring from an iodine sufficient area. Urinary iodine concentration in pregnant women from the endemic area (1.28 +/- 0.13 micrograms/dl, mean +/- SE) was significantly lower than that of pregnant women from the iodine sufficient area (3.77 +/- 0.57 micrograms/dl) (t = 3.56, p less than 0.005). The longitudinal measurement of iodine concentration in each nursing woman showed a marked increase (approximately 90%) when compared with the values obtained during pregnancy in both endemic and control groups (2.32 +/- 0.36 and 7.76 +/- 2.08 micrograms/dl; t = 2.13 p less than 0.05, respectively). The slight difference in milk iodine concentration between the endemic (3.25 +/- 0.77 micrograms/dl) and the control (4.33 +/- 0.57 micrograms/dl) group was not statistically significant (t = 1.14; p less than 0.5, NS). Similarly no difference was found in urinary iodine excretion between the endemic and the control newborn groups (3.41 +/- 0.76 and 4.30 +/- 0.65 micrograms/dl, respectively, t = 0.88 p less than 0.1, NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiology and clinical characteristics of endemic cretinism in Sicily.

In this study we report the prevalence of endemic cretinism in the general population of two iodine deficient areas in Northeastern Sicily that were described more than 10 yr ago. In addition, the individual characteristics of endemic cretins are considered in order to define the typical expressions of this major iodine deficiency disorder in Sicily. Forty-three mental defectives were identified: 22 were living in an area with three bordering and closely connected municipalities within the province of Messina and with a population of 17,485 inhabitants (prevalence = 0.13%). Three out of the 22 were school-age children. The other community, in the province of Catania, was constituted by a unique and mostly agricultural hamlet, and showed a prevalence of cretinism that was 0.68% (21/3,100). Among the 43 mental defectives, 16 (37%) presented prominent neuromotor and neurosensorial disorders, including deafmutism and were euthyroid, thus conforming to the neurological type of cretinism; 13 (30%) were hypothyroid and exhibited stunted growth without significant neuromotor and neurosensorial impairment (myxedematous cretins). In the remaining 14 individuals (33%) neurological disorders were associated with stunted growth and clinical or biochemical hypothyroidism. These data indicate that also in Sicily endemic cretinism is a continuum of a variety of forms: among these the pure neurological and pure myxedematous forms represent the two extremes. Our observations also indicate that endemic cretinism still represents a major public health problem in Sicily. The finding of 3 endemic cretins younger than 13 yr suggests the persistence of this disorder even in the presence of improved economic, social and nutritional conditions.

Defective neuromotor and cognitive ability in iodine-deficient schoolchildren of an endemic goiter region in Sicily.

Visual perceptual integrative motor ability was investigated in 719 6- to 12-yr-old, presumably normal, primary schoolchildren living in 2 iodine-deficient endemic goiter areas in Sicily, identified on the basis of the presence (area A) or absence (area B) of endemic cretinism, by administrating the Bender Gestalt test. All of these clinically euthyroid schoolchildren were also examined neurologically by an investigator unaware of the result of the Bender test. Ninety-nine (13.76%) schoolchildren were found to be defective by the Bender test; this prevalence was significantly higher than that (3.0%) found in an iodine-sufficient goiter-free control area (area C) lying at sea level (chi 2 = 36.25; P less than 0.000001). No difference in the prevalence of Bender abnormalities was apparent if the children were divided according to the area of provenience (area A, 14.4%; area B, 13.1%). A high percentage of children falling in the lower range of normality was found in both area A (15.5%) and area B (19.0%); this was significantly higher than that in area C (3.8%; chi 2 = 77.55; P less than 0.000001). Neuromuscular and neurosensorial abnormalities, including increased tendon reflexes, clonus of the foot, Babinski sign, minor disturbances in balance, and gait, and minor defects in hearing and speech, were apparent in 19.3% (area A) and 18.5% (area B) of the children. These disorders were significantly more frequent in defective children identified by the Bender test (33.3%) than in normal children (15.3%; (chi 2 = 17.29; P less than 0.00005). The general intellectual aptitude in Bender deficient subjects was evaluated by the Terman Merrill test and was found to be impaired in 95%, thus confirming the existence of an endemic cognitive deficiency (ECD), distinct from the endemic mental deficiency previously found in other endemic goiter, iodine-deficient areas. ECD seems to be epidemiologically independent of the existence of endemic cretinism. Further clinical auxological and biochemical studies in a selected group of ECD children suggested the epidemiological and, possibly, pathogenic association of cognitive impairment with iodine deficiency.

Autoantibodies to thyroxin and triiodothyronine in the immunoglobulin G fraction of serum.

Thyroid hormone antibodies (THAbs)--i.e., antibodies to thyroxin (T4) and triiodothyronine (T3)--are detected rarely in human serum, where they are searched for, possibly because of a quantitatively minimal interaction between thyroid hormones (the haptens) and serum IgGs (the antibodies). The weak binding could result from these facts: (a) there are already six physiological carrier proteins for thyroid hormones; (b) THAbs usually account for a very small fraction of the total serum IgGs; (c) THAbs may have--as reported in the literature--a relatively low affinity. To ascertain whether THAbs could pass undetected in serum, we measured antibodies to T3 and T4 in both the serum and the corresponding IgG fraction of six normal persons and 45 patients with various thyroid diseases (Graves' disease, idiopathic myxedema, Hashimoto's thyroiditis, subacute thyroiditis, tumors), using radioimmunoprecipitation. The prevalence of antibodies to T4 was 0/51 in both the sera and the IgG fractions; the prevalence of antibodies to T3 was 1/51 in both materials. Because all of the sera that tested THAb negative were confirmed to be so in the THAb assay of the IgG fraction, we conclude that the prevalence of serum THAbs is not underestimated and that autoimmunization against thyroid hormones is really a rare phenomenon.

Detection and characterization of autoantibodies blocking the TSH-dependent cAMP production using FRTL-5 cells.

Autoantibodies blocking the TSH-stimulated cAMP production (TBkAb) were measured in immunoglobulin G (IgG) preparations from 38 patients with primary autoimmune hypothyroidism, using FRTL-5 cells. TBkAb were detectable in 15/23 IgG preparations from patients with untreated idiopathic myxedema, and in 2/15 IgGs from patients under L-thyroxine treatment. None of the IgG from 22 normal subjects or from 10 patients with nonautoimmune hypothyroidism following total thyroidectomy caused any significant effect on the TSH-stimulated cAMP production. No correlation was found between TBkAb and the thyroid microsomal antibody. Antibodies inhibiting the 125I-TSH binding to TSH receptor were detectable in only 3/20 patients; IgGs from these 3 patients were also positive in the TBkAb assay. One IgG with potent TBkAb activity inhibited the TSH-stimulated adenylate cyclase in a competitive manner, while it had no effect on the forskolin-stimulated cAMP production. The inhibiting action of this IgG was almost completely lost after preabsorption with human thyroid membranes. In conclusion, we describe a new practical and sensitive method for the measurement of TBkAb; TBkAb are distinct from the microsomal antibody, and are probably directed to the TSH receptor.

Increased serum thyroglobulin concentrations and impaired thyrotropin response to thyrotropin-releasing hormone in euthyroid subjects with endemic goiter in Sicily: their relation to goiter size and nodularity.

Serum thyroglobulin (Tg), T4, T3, FT4, FT3, TSH concentrations and TSH response to iv TRH (delta TSH) were measured in 56 consecutive patients with (multi) nodular goiter from a severely iodine-deficient endemic goiter area in Northeastern Sicily and in 11 non goitrous euthyroid individuals living in the same area. Serum Tg concentrations were sharply increased in goitrous subjects (453 +/- 476 ng/ml) and related to thyroid size and the presence of nodules (chi 2 = 43.5, p less than 0.0005). Serum TSH levels measured in goitrous patients (2.1 +/- 0.9 microU/ml) were significantly lower than those measured in nongoitrous iodine deficient subjects (3.1 +/- 0.9 microU/ml, p less than 0.001) and decreased with increasing goiter size and nodularity (chi 2 = 27.3, p less than 0.05). A similar pattern was shown by the analysis of the delta TSH (chi 2 = 43.1, p less than 0.0005). These results suggest that at least a part of the largest and multinodular goiters become autonomously functioning with duration and growing in size. In 13 goitrous patients with absent or impaired response to TRH, a significant direct relation was apparent between log-Tg and goiter size and nodularity (r = 0.64) with an inverse relationship between serum FT3 and delta TSH (r = 0.73). A computed program analysis based on the combination of different independent variables (x) including age, thyroid size and nodularity, serum TSH, log-Tg and FT3, indicated the existence of a significant negative relationship between these variables and the TSH response to TRH (r = 0.75, p = 0).(ABSTRACT TRUNCATED AT 250 WORDS)