Decreasing Tendency (decreasing + tendency)

Distribution by Scientific Domains


Selected Abstracts


Epidemiological data on consumer allergy to p -phenylenediamine

CONTACT DERMATITIS, Issue 6 2008
Jacob Pontoppidan Thyssen
Many women and men now dye their hair. p-Phenylenediamine (PPD) is a frequent and important component of permanent hair dye products; exposure to it may cause allergic contact sensitization, acute dermatitis, and severe facial oedema. To increase our understanding of PPD allergy, we reviewed published literature containing PPD patch test data from dermatitis patients and individuals in the general population. This was performed to estimate the median prevalence and the weighted average of PPD sensitization and thereby assess the burden of PPD-containing hair care products on health. Literature was examined using PubMed,MEDLINE, Biosis, and Science Citation Index. The median prevalence among dermatitis patients was 4.3% in Asia, 4% in Europe, and 6.2% in North America. A widespread increase in the prevalence of PPD sensitization was observed among Asian dermatitis patients. In Europe, a decrease in the 1970s was replaced by a plateau with steady, high prevalences ranging between 2% and 6%. The prevalence remained high in North America, although a decreasing tendency was observed. Contact allergy to PPD is an important health issue for both women and men. More stringent regulation and enforcement are required as public health measures to reduce the burden of disease that exposure to PPD has brought to populations. [source]


Altered small-world brain functional networks in children with attention-deficit/hyperactivity disorder

HUMAN BRAIN MAPPING, Issue 2 2009
Liang Wang
Abstract In this study, we investigated the changes in topological architectures of brain functional networks in attention-deficit/hyperactivity disorder (ADHD). Functional magnetic resonance images (fMRI) were obtained from 19 children with ADHD and 20 healthy controls during resting state. Brain functional networks were constructed by thresholding the correlation matrix between 90 cortical and subcortical regions and further analyzed by applying graph theoretical approaches. Experimental results showed that, although brain networks of both groups exhibited economical small-world topology, altered functional networks were demonstrated in the brain of ADHD when compared with the normal controls. In particular, increased local efficiencies combined with a decreasing tendency in global efficiencies found in ADHD suggested a disorder-related shift of the topology toward regular networks. Additionally, significant alterations in nodal efficiency were also found in ADHD, involving prefrontal, temporal, and occipital cortex regions, which were compatible with previous ADHD studies. The present study provided the first evidence for brain dysfunction in ADHD from the viewpoint of global organization of brain functional networks by using resting-state fMRI. Hum Brain Mapp, 2009. © 2008 Wiley-Liss, Inc. [source]


Features of cross-Pacific climate shown in the variability of China and US precipitation

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 13 2005
Q. Li
Abstract In this study, we have analyzed the climate features of China and the United States with a focus on the differences, similarities, connectivity, and predictability of precipitation and the relationships between precipitation and large-scale patterns of natural variability. China precipitation is characterized by large seasonality, with a maximum in summer and a minimum in winter. The seasonality of precipitation shows an increasing linear tendency in northwest China, with a change of about 20% from 1901 to 1998. A relatively weaker increasing tendency also appears in the Big Bend of Yellow River (BBYR) and the Tibetan Plateau, while southwest China experiences a decreasing tendency. Furthermore, the seasonality in the BBYR shows particularly significant interdecadal variability, while that of southern and eastern China has decreased slightly in the recent decades. Compared to China, the United States as a whole has less precipitation in summer but more precipitation in other seasons. Here, the seasonality of precipitation is only about 24% of that in China. The annual mean precipitation is 64.1 mm per month in the United States, compared to 54.6 mm per month in China. The seasonality of precipitation exhibits a decreasing tendency in the southeast, Pacific Northwest, and Gulf Coast and an increasing tendency in the Great Lakes. The seasonality in the Great Plains exhibits large interdecadal variability. The long-term variations of precipitation are highly seasonally dependent. In summer, a decreasing trend is observed in north China and an increasing trend is found in eastern-central China. However, these trends are almost opposite in spring. In addition, the fall precipitation decreases with time nearly everywhere in China except for the middle and lower reaches of the Yangtze River Valley. Results also indicate that the El Niño/Southern Oscillation (ENSO), the Arctic Oscillation (AO), the North Atlantic Oscillation (NAO), the Pacific Decadal Oscillation (PDO), and the North Pacific (NP) fluctuation affect strongly the variations of China and US precipitation. Although these influences vary with regions and seasons, we in particular emphasize the importance of AO and NAO for China precipitation and NP and PDO for US precipitation. In fall, ENSO and PDO are the two phenomena that influence predominantly precipitation variability in both China and the United States We also identify the common phenomena that influence China and US regional precipitation and provide a better understanding of the physical mechanism for precipitation variability through the associated changes in atmospheric and oceanic conditions. Furthermore, we develop a linear regression model, based on multiple regression method by combining the regionally and seasonally varying impacts, to increase the skill of precipitation prediction. Copyright © 2005 Royal Meteorological Society [source]


Histological evidences suggest recommending orchiopexy within the first year of life for children with unilateral inguinal cryptorchid testis

INTERNATIONAL JOURNAL OF UROLOGY, Issue 7 2007
Kwan Hyun Park
Objective: To determine the optimal timing for orchiopexy, we evaluated the histological parameters of the cryptorchid testis. Methods: We prospectively performed testicular biopsy in a total of 65 consecutive children with palpable unilateral inguinal cryptorchid testes. For controls, we used testicular histological slides from 15 age-matched children with testicular tumor. To investigate the fertility potential, we analyzed the parameters including mean tubular diameter (MTD), mean tubular fertility index (MTFI), germ cell count/tubule (GCC), Sertoli cell index (SCI) and interstitial fibrosis index (IFI). Results: The MTFI and GCC in children ,1 years of age were significantly higher than those of other older age groups. The MTFI, GCC and IFI were significantly better in patients ,2 years of age when compared to those of > 2 years. Compared to the controls, the MTFI and GCC in the patients were significantly worse in those aged > 2 years at surgical repair. In the ,2-year age group, the MTFI and GCC of the cryptorchid testis showed a decreasing tendency with age, which were contrasting with the ascending curves in the control and the curves crossed at 1,2 years of age in each parameter. Conclusions: To protect fertility potential, we recommend, orchiopexy should be performed within the first year of life, and no later than 2 years of age in patients with palpable inguinal cryptorchid testes. [source]


Morphology and thermal and dielectric behavior of cycloaliphatic epoxy/trimethacrylate interpenetrating polymer networks for vacuum-pressure-impregnation electrical insulation

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008
Jingkuan Duan
Abstract Vacuum pressure impregnation has been known as the most advanced impregnation technology that has ever been developed for large and medium high-voltage electric machines and apparatuses. We developed one new type of vacuum-pressure-impregnation resin with excellent properties by means of a novel approach based on in situ sequential interpenetrating polymer networks resulting from the curing of trimethacrylate monomer [trimethylol-1,1,1-propane trimethacrylate (TMPTMA)] and cycloaliphatic epoxy resin (CER). In this study, the influence of the concentrations of the components and their microstructures on their thermal and dielectric behaviors were investigated for the cured CER/TMPTMA systems via atomic force microscopy, dynamic mechanical analysis, thermogravimetric analysis, and dielectric analysis. The investigation results show that the addition of TMPTMA to the CER,anhydride system resulted in the formation of a uniform and compact microstructure in the cured epoxy system. This led the cured CER/TMPTMA systems to show much higher moduli in comparison with the pure CER,anhydride system. The thermogravimetric analysis results show that there existed a decreasing tendency in the maximum thermal decomposition rates of the cured CER/TMPTMA systems, which implies that the thermal stability properties improved to some extent. The dielectric analysis results show that the cured CER/TMPTMA systems displayed quite different dielectric behaviors in the wide frequency range 0.01 Hz,1 MHz and in the wide temperature range 27,250°C compared with the cured CER,anhydride system. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]


Temporal patterns of growth in larval cohorts of the Japanese sardine Sardinops melanostictus in a coastal nursery area

JOURNAL OF FISH BIOLOGY, Issue 6 2008
G. Plaza
Growth patterns of larval sardine Sardinops melanostictus were studied in a coastal nursery area, in southern Japan for four monthly hatch cohorts of larvae (November, December, January and February) for the 2003,2004 and 2004,2005 seasons. Laird,Gompertz models were fitted to each cohort using both total length (LT)-at-age at capture and mean LT -at-age data derived from backcalculations. In both approaches, the absolute daily growth rates (GR) and absolute daily growth rates at the inflection point (GXO) were estimated. In parallel, individual growth rates (GI) were derived from backcalculated LT (LB). Growth showed the following general common patterns irrespective of hatch month, season and methods: (1) significant Laird,Gompertz fits, (2) asymptotic growth, (3) a decrease in GR after the inflexion point, except for February for the 2003,2004 season that showed an apparent constant growth pattern, (4) six in eight cohorts showed GXO ranging from 0·8 to 1·2 mm day,1 and (5) a decreasing tendency of GI from 1·75 to 0·24 mm day,1, from first feeding through the first month of larval life. The contrasting pattern between the 2003,2004 and the 2004,2005 seasons were: (1) allometric v. logarithmic (ln) LT and otolith radius relationships, (2) low GXOv. high GXO, (3) high GRv. low GR when growth turned asymptotic, (4) low GXOv. high GXO when monthly hatch cohorts were combined and (5) LB and GI not differing among monthly hatch cohorts. The differences in growth patterns and growth rates between seasons seemed to be linked to the influx of warmer and oligotrophic waters of the Kuroshio Current that triggered an increase of 3° C in the coastal area for the 2003,2004 seasons. In the overall context, however, the high GXO, within cohorts and seasons reported in the current study, suggests that either sea surface temperature (SST) or food availability, or both are in the optimal range of preferences for S. melanostictus larvae. Consequently, nearshore coastal areas seem to be playing an important role as a nursery area for the larval stage of this species. [source]


Monocyte cytokine and costimulatory molecule expression in patients infected with Leishmania mexicana

PARASITE IMMUNOLOGY, Issue 3 2007
G. CARRADA
SUMMARY Leishmania mexicana causes localized and diffuse cutaneous leishmaniasis. Patients with localized cutaneous leishmaniasis (LCL) develop a benign disease, whereas patients with diffuse cutaneous leishmaniasis (DCL) suffer from a progressive disease associated with anergy of the cellular response towards Leishmania antigens. We evaluated the production of the interleukins (IL) IL-12, IL-15, IL-18 and tumour necrosis factor-, (TNF-,) and the expression of the costimulatory molecules CD40, B7-1 and B7-2 in monocytes from LCL and DCL patients, stimulated in vitro with Leishmania mexicana lipophosphoglycan (LPG) for 18 h. LCL monocytes significantly increased TNF-,, IL-15 and IL-18 production, and this increase was associated with reduced amounts of IL-12. DCL monocytes produced no IL-15 or IL-18 and showed a decreasing tendency of TNF-, and IL-12 production as the severity of the disease increased. No difference was observed in the expression of CD40 and B7-1 between both groups of patients, yet B7-2 expression was significantly augmented in DCL patients. It remains to be established if this elevated B7-2 expression in DCL patients is cause or consequence of the Th2-type immune response that characterizes these patients. These data suggest that the diminished ability of the monocytes from DCL patients to produce cell-activating innate proinflammatory cytokines when stimulated with LPG is a possible cause for disease progression. [source]


REE, Mn, Fe, Mg and C, O Isotopic Geochemistry of Calcites from Furong Tin Deposit, South China: Evidence for the Genesis of the Hydrothermal Ore-forming Fluids

RESOURCE GEOLOGY, Issue 1 2010
Yan Shuang
Abstract The Furong tin deposit in the central Nanling region, South China, consists of three main types of mineralization ores, i.e. skarn-, altered granite- and greisen-type ores, hosted in Carboniferous and Permian strata and Mesozoic granitic intrusions. Calcite is the dominant gangue mineral intergrown with ore bodies in the orefield. We have carried out REE, Mn, Fe, and Mg geochemical and C, and O isotopic studies on calcites to constrain the source and evolution of the ore-forming fluids. The calcites from the Furong deposit exhibit middle negative Eu anomaly (Eu/Eu*= 0.311,0.921), except for one which has an Eu/Eu* of 1.10, with the total REE content of 5.49,133 ppm. The results show that the calcites are characterized by two types of REE distribution patterns: a LREE-enriched pattern and a flat REE pattern. The LREE-enriched pattern of calcites accompanying greisen-type ore and skarn-type ore are similar to those of Qitianling granite. The REE, Mn, Fe, and Mg abundances of calcites exhibit a decreasing tendency from granite rock mass to wall rock, i.e. these abundances of calcites associated with altered granite-type and greisen-type ores are higher than those associated with skarn-type ores. The calcites from primary ores in the Furong deposit show large variation in carbon and oxygen isotopic compositions. The ,13C and ,18O of calcites are ,0.4 to ,12.7, and 2.8 to 16.4,, respectively, and mainly fall within the range between mantle or magmatic carbon and marine carbonate. The calcites from greisen and altered granite ores in the Furong deposit display a negative correlation in the diagram of ,13C versus ,18O, probably owing to the CO2 -degassing of the ore-forming fluids. From the intrusion to wall-rock, the calcites display an increasing tendency with respect to ,13C values. This implies that the carbon isotopic compositions of the ore-bearing fluids have progressively changed from domination by magmatic carbon to sedimentary carbonate carbon. In combination with other geological and geochemical data, we suggest that the ore-forming fluids represent magmatic origin. We believe that the fluids exsolved from fractionation of the granitic magma, accompanying magmatism of the Qitianling granite complex, were involved in the mineralization of the Furong tin polymetallic deposit. [source]