The structure and optical properties of ZnO nanocrystals embedded in SiO2 fabricated by radio-frequency sputtering

Zinc oxide (ZnO) nanocrystals (NCs) with high crystalline quality were prepared via radio-frequency magnetron sputtering as a SiO(2)/ZnO/SiO(2) trilayer on Si(100) and Al(2)O(3)(0001) substrates with an intermediate in situ annealing step. Transmission electron microscopy reveals a uniform dispersion of ZnO NCs in the amorphous SiO(2) matrix with typical sizes up to 16 nm with a larger fraction of smaller crystals. The size distribution analysis yields a mean grain size of 5 nm for small particles. Individual ZnO NCs show a well-defined hexagonal close packed wurtzite structure and lattice parameters close to those of bulk ZnO, confirming their high crystalline quality. Mapping of the Zn distribution by means of energy-filtered transmission electron microscopy reveals a strongly non-uniform distribution of Zn within the SiO(2) matrix, corroborating the chemical separation of ZnO NCs from surrounding SiO(2). Optical transmittance measurements confirm the findings of the electron microscopy analysis. The fabrication technique described opens up new possibilities in the preparation of ZnO NCs with high crystalline quality, including growth in monolithic optical cavities without intermediate ex situ fabrication steps.

[Could the screening of autoimmune diseases be simplified?]

Autoimmune diseases (AD) represent usually a big challenge for the general physician (GP) and are often under diagnosed because of their rarity and their complex clinical symptoms. Even though AD are rapidly suspected, the GP is often exposed to the difficulty of screening and the complexity of the various biological tests at his disposal. This article propose the way to simplify the primary diagnostic approach of AD which often need a further specialized counseling necessary to determine the therapy.

OmpA and antigenic diversity of bovine Chlamydophila pecorum strains

Infections with the intracellular bacterium Chlamydophila (C.) pecorum are highly prevalent worldwide in cattle. These infections cause significant diseases such as polyarthritis, pneumonia, enteritis, genital infections and fertility disorders, and occasionally sporadic bovine encephalomyelitis. Subclinical respiratory infections of calves with C. pecorum have been associated with airway obstruction, pulmonary inflammation, and reduced weight gains. This investigation examined four chlamydial strains with biological properties of C. pecorum isolated from feces of clinically normal cattle, from calves with pneumonia, and from bulls with posthitis. The objective was to characterize the evolutionary relationships of these bovine chlamydial isolates to other chlamydiae by genetic analysis of the ompA gene, and by the immunological cross-reactivities in Western immunoblot analysis. PCR typing of the ompA gene identified these isolates as C. pecorum. The OmpA-deduced amino acid dissimilarities between these four strains spanned 10-20%. In phylogenetic analysis, the four isolates clustered with C. pecorum ruminant, porcine, and koala strains of different geographic origins rather than with each other. All four isolates showed different patterns of Western immunoblot reactivity with antiserum against bovine C. pecorum strain LW63, and, interestingly, no cross-reactivity of the OmpA proteins with the anti-LW613 OmpA antibodies. These data underscore the polyphyletic population structure of C. pecorum and suggest that the spectrum of C. pecorum OmpA proteins in a host species can occupy the entire evolutionary bandwidth within C. pecorum. The variant immunoblot reactivities support the notion of considerable genomic plasticity of C. pecorum.

Homeopathic pathogenetic trials produce more specific than non-specific symptoms: results from two double-blind placebo controlled trials

We conducted two parallel, blinded homeopathic pathogenetic trials conducted at two different sites to determine whether symptoms reported by healthy volunteers were significantly different for homeopathic remedies than for placebos. Study 1 used a two-armed design, testing ozone against placebo. Study 2 used a three-armed design, testing ozone and iridium against placebo. We found significantly more remedy-specific symptoms in provers taking ozone or iridium than in provers taking placebo in the three-armed trial and in both trials pooled for ozone and placebo. We, therefore, conclude that homeopathic remedies produce more symptoms typical for a remedy than non-typical symptoms. The results furthermore suggest a somewhat non-classical pattern because symptoms of one remedy appear to be mimicked in the other trial arm. This might be indicative of entanglement in homeopathic systems.

Modeling of surface-dominated plasmas: from electric thruster to negative ion source

This contribution shows two important applications of the particle-in-cell/monte Carlo technique on ion sources: modeling of the Hall thruster SPT-100 for space propulsion and of the rf negative ion source for ITER neutral beam injection. In the first case translational degrees of freedom are involved, while in the second case inner degrees of freedom (vibrational levels) are excited. Computational results show how in both cases, plasma-wall and gas-wall interactions play a dominant role. These are secondary electron emission from the lateral ceramic wall of SPT-100 and electron capture from caesiated surfaces by positive ions and atoms in the rf negative ion source.

Development of SRS.php, a Simple Object Access Protocol-based library for data acquisition from integrated biological databases

Data integration has become an important task for biological database providers. The current model for data exchange among different sources simplifies the manner that distinct information is accessed by users. The evolution of data representation from HTML to XML enabled programs, instead of humans, to interact with biological databases. We present here SRS.php, a PHP library that can interact with the data integration Sequence Retrieval System (SRS). The library has been written using SOAP definitions, and permits the programmatic communication through webservices with the SRS. The interactions are possible by invoking the methods described in WSDL by exchanging XML messages. The current functions available in the library have been built to access specific data stored in any of the 90 different databases (such as UNIPROT, KEGG and GO) using the same query syntax format. The inclusion of the described functions in the source of scripts written in PHP enables them as webservice clients to the SRS server. The functions permit one to query the whole content of any SRS database, to list specific records in these databases, to get specific fields from the records, and to link any record among any pair of linked databases. The case study presented exemplifies the library usage to retrieve information regarding registries of a Plant Defense Mechanisms database. The Plant Defense Mechanisms database is currently being developed, and the proposal of SRS.php library usage is to enable the data acquisition for the further warehousing tasks related to its setup and maintenance.

Quecksilber und Alzheimer-Erkrankung

Higher mercury concentrations were found in brain regions and blood of some patients with Alzheimer's disease (AD). Low levels of inorganic mercury were able to cause AD- typical nerve cell deteriorations in vitro and in animal experiments. Other metals like zinc, aluminum, copper, cadmium, manganese, iron, and chrome are not able to elicit all of these deteriorations in low levels, yet they aggravate the toxic effects of mercury (Hg). Main human sources for mercury are fish consumption (Methyl-Hg) and dental amalgam (Hg vapour). Regular fish consumption reduces the risk of development of AD. Amalgam consists of approx. 50 % of elementary mercury which is constantly being vaporized and absorbed by the organism. Mercury levels in brain tissues are 2 - 10 fold higher in individuals with dental amalgam. Persons showing a genetically determined subgroup of transportation protein for fats (apolipoprotein E4) have an increased AD risk. Apoliprotein E (APO E) is found in high concentrations in the central nervous system. The increased AD risk through APO E4 might be caused by its reduced ability to bind heavy metals. Latest therapeutic approaches to the treatment of Alzheimer disease embrace pharmaceuticals which remove or bind metals from the brain. Preliminary success has been documented with chelation of synergistic toxic metals (Fe, Al, Zn, Cu) and therefore also Hg. The available data does not answer the question, whether mercury is a relevant risk factor in AD distinctively. In sum, the findings from epidemiological and demographical studies, the frequency of amalgam application in industrialized countries, clinical studies, experimental studies and the dental state of Alzheimer patients in comparison to controls suggest a decisive role for inorganic mercury in the etiology of Alzheimer's disease. Other factors currently discussed as causes (e. g. other metals, inflammations, dietetic factors, vitamin deficiency, oxidative distress, and metabolic impairments) may act as co-factors.

Intrathecal IgM-synthesis does not correlate with the risk of relapse in patients with a primary demyelinating event

The objective of this study was to investigate, whether the presence of oligoclonal immunoglobulin M bands (IgM-OCB) in cerebrospinal fluid (CSF) from patients with a clinically isolated syndrome (CIS), which is suggestive for the first clinical manifestation of multiple sclerosis (MS), anticipates the risk of a relapse during a retrospective study period of 21-106 months (mean 60 +/- 25). A relapse would lead to the diagnosis of clinically definite MS. Paired CSF and serum samples from 42 patients with a CIS and positive intrathecal IgG-synthesis were tested retrospectively for IgM-OCB, which are exclusively present in CSF, but not in the corresponding serum. Isoelectric focusing and affinity blot were used and clinical follow-up was based on telephone interviews. IgM-OCB were found in the CSF from 31 of 42 patients (74%). There was no correlation between the presence of IgM-OCB, the number of such bands or the IgM-Index on the one hand and the risk of a relapse during the follow-up in the cohort studied, on the other hand. These data do not support the idea that the presence of IgM-OCB in CSF might predict an unfavourable course in MS.

Epidemiology of juvenile idiopathic arthritis in a multiethnic cohort: ethnicity as a risk factor

OBJECTIVE

To study the influence of ethnicity on the risk of developing juvenile idiopathic arthritis (JIA) in a multiethnic community of patients with unrestricted access to health care.

METHODS

A questionnaire on ethnicity was distributed to all patients with JIA being followed up at the Hospital for Sick Children in Toronto, Ontario, Canada. Of 1,082 patients, 859 (79.4%) responded to the questionnaire. To calculate the relative risk (RR) of developing JIA in this study cohort, the results were compared with data from the age-matched general population of the Toronto metropolitan area (TMA) as provided in the 2001 census from Statistics Canada.

RESULTS

European descent was reported by 69.7% of the patients with JIA compared with a frequency of 54.7% in the TMA general population, whereas a statistically significantly lower than expected percentage of the patients with JIA reported having black, Asian, or Indian subcontinent origin. Children of European origin had a higher RR for developing any of the JIA subtypes except polyarticular rheumatoid factor (RF)-positive JIA, and were particularly more likely to develop the extended oligoarticular and psoriatic subtypes. A higher frequency of enthesitis-related JIA was observed among patients of Asian origin, while those of black origin or native North American origin were more likely to develop polyarticular RF-positive JIA.

CONCLUSION

In this multiethnic cohort, European descent was associated with a significantly increased risk of developing JIA, and the distribution of JIA subtypes differed significantly across ethnic groups.

Histopathological prevalence of subchondral insufficiency fracture of the femoral head

OBJECTIVE

Subchondral insufficiency fracture of the femoral head (SIF) is a recently recognised cause of acute onset arthritis mostly in older women, which previously had been commonly considered either as osteonecrosis or osteoarthritis. The purpose of this study is to report the histopathological incidence of SIF using surgically removed femoral heads.

METHODS

We reviewed 7718 consecutive femoral heads from 7286 patients removed over a 4-year period (2001-2004). There were 4211 women and 3507 men. The age range was from 13 to 96, average age was 60. There were 7349 hips with a preoperative clinical diagnosis of osteoarthritis and 369 with a preoperative clinical diagnosis of osteonecrosis.

RESULTS

SIF was diagnosed histologically as the primary process in 501 of 7718 resected femoral heads (6.5%). The age range in these patients was from 20 to 93, with an average age of 68, in which 79% (394 hips) were over 60. They were 305 hips in women and 196 in men. The affected side was the right one in 253 hips and left in 248. The prevalence of SIF in cases with a preoperative diagnosis of osteoarthritis was 6.3% (460 of 7349), and with osteonecrosis was 11.1% (41 of 369). In all cases, callus and granulation tissue were observed histologically along the fracture line.

CONCLUSIONS

In this large series of total hip replacements SIF as the cause of disease was diagnosed histologically in 6.5% of the surgically removed femoral heads.

Downregulation of organic anion transporters OAT1 and OAT3 correlates with impaired secretion ofpara-aminohippurate after ischemic acute renal failure in rats

Ischemic acute renal failure (iARF) was described to reduce renal extraction of the organic anion para-aminohippurate (PAH) in humans. The rate-limiting step of renal organic anion secretion is its basolateral uptake into proximal tubular cells. This process is mediated by the organic anion transporters OAT1 and OAT3, which both have a broad spectrum of substrates including a variety of pharmaceutics and toxins. Using a rat model of iARF, we investigated whether impairing the secretion of the organic anion PAH might be associated with downregulation of OAT1 or OAT3. Inulin and PAH clearance was determined starting from 6 up to 336 h after ischemia-reperfusion (I/R) injury. Net secretion of PAH was calculated and OAT1 as well as OAT3 expression was analyzed by RT-PCR and Western blotting. Inulin and PAH clearance along with PAH net secretion were initially diminished after I/R injury with a gradual recovery during follow-up. This initial impairment after iARF was accompanied by decreased mRNA and protein levels of OAT1 and OAT3 in clamped animals compared with sham-operated controls. In correlation to the improvement of kidney function, both mRNA and protein levels of OAT1 and OAT3 were upregulated during the follow-up. Thus decreased expression of OAT1 and OAT3 is sufficient to explain the decline of PAH secretion after iARF. As a result, this may have substantial impact on excretion kinetics and half-life of organic anions. As a consequence, the biological effects of a variety of organic anions may be affected after iARF.

Reduction of X-ray-induced radiation damage of macromolecular crystals by data collection at 15 K: a systematic study

The cryocooling of protein crystals to temperatures of around 100 K drastically reduces X-ray-induced radiation damage. The majority of macromolecular data collection is therefore performed at 100 K, yielding diffraction data of higher resolution and allowing structure determination from much smaller crystals. However, at third-generation synchrotron sources radiation damage at 100 K still limits the useful data obtainable from a crystal. For data collection at 15 K, realised by the use of an open-flow helium cryostat, a further reduction of radiation damage is expected. However, no systematic studies have been undertaken so far. In this present study, a total of 54 data sets have been collected from holoferritin and insulin crystals at 15 and 90 K in order to identify the effect of the lower data-collection temperature on the radiation damage. It is shown that data collection at 15 K has only a small positive effect for insulin crystals, whereas for holoferritin crystals radiation damage is reduced by 23% compared with data collection at 90 K.

libRASCH--a programming framework for transparent access to physiological signals

For the analysis of physiological signals, such as ECG's, continuous blood pressure recordings etc., access to the raw signal data as well as to processed data is mandatory. Up to now, there is no computer program which allows access to raw and processed data independently from the file formats used. Thus, programs have to be adapted to each new file format. The aim of the programming library 'libRASCH', is to provide an interface which allows the access to physiological signals in a consistent way. libRASCH is written in C and runs under Linux and Windows. The source code of libRASCH is published under the GNU LGPL. A plugin mechanism for extension of the library was implemented. Support for some widely used data formats (e.g. European Data Format) is already available. To support a new file-format, only the corresponding plugin has to be written. Moreover all programs using this library, can handle the new format without further adjustments. For other programming languages than C (e.g. Perl, Python), interfaces are available. On the libRASCH website (http://www.librasch.org), the source code of libRASCH and further information's are available.

Massive hemoptysis in an 11-year-old girl with isolated pulmonary arteritis

A 10-year-old girl developed recurrent bouts of massive hemoptysis over a 9-month period. No obvious bleeding source was detected. Her pulmonary angiogram showed a pulmonary aneurysm of the second branch of the left main pulmonary artery as well as widespread irregularities of the pulmonary arteries including areas of stenosis and pruning. Elective embolization of the aneurysm did not control hemoptysis and emergency left upper lobectomy had to be performed. Histology showed large artery wall injury with acute leucocytoclastic inflammation, fibrinoid necrosis, granulomatous inflammation, and ectasia of vessel wall. This combination of abnormalities has not been described to date and represents the first case of isolated pulmonary arteritis in children prior to puberty.

Prevalence, risk factors, and outcome of uveitis in juvenile idiopathic arthritis: A long-term followup study

OBJECTIVE

To assess the prevalence, risk factors, and long-term outcome of uveitis in patients with juvenile idiopathic arthritis (JIA).

METHODS

An inception cohort of all 1,081 patients diagnosed as having JIA at a single tertiary care center was established. A questionnaire and followup telephone calls were used to confirm the diagnosis of uveitis. Ophthalmologists' records of patients with uveitis were collected. Kaplan-Meier and Cox regression analyses were used to assess risk factors for developing uveitis and for complications of uveitis.

RESULTS

After a mean followup time of 6.9 years, 142 of 1,081 patients (13.1%) had developed uveitis. Risk factors were young age at diagnosis, female sex, antinuclear antibody positivity, and the subtype of JIA. The relative contribution of these risk factors was different for the different subtypes of JIA. Until the end of the study, uveitis complications had developed in 53 of 142 patients with uveitis (37.3%; 4.9% of the total cohort). Only 16 of 175 involved eyes (9.1%) in 14 of 108 patients (13%; 1.3% of the total cohort) for whom ophthalmology reports were available had best corrected visual acuity less than 20/40 (mean followup time for uveitis of 6.3 years). Abnormal vision was associated with synechiae or cataract.

CONCLUSION

Risk factors for developing uveitis were different among subtypes of JIA. The long-term outcome of JIA-associated uveitis in our cohort was excellent despite the high rate of complications.

Cognitive plasticity in people at risk for dementia: optimising the testing-the-limits-approach

A topic of great interest in gerontology research is the prediction of cognitive deterioration which marks the transition from mild cognitive impairment (MCI) to dementia. In this area, the term cognitive plasticity can be of great interest. We examined the utility of the Adaptive Figure Series Learning Test (ADAFI) to evoke cognitive plasticity and to show whether reduced plasticity can be found in people with MCI. In a pre-test-intervention-post-test design, intervention with the ADAFI was compared to an unspecific brain jogging task in MCI participants and healthy controls. A total of 42 subjects were included. Independent of mental health status only using the ADAFI led to pronounced improvements in post-test performances, but MCI participants profited less from the intervention with the ADAFI than healthy controls, that is, showed lower cognitive plasticity. Thus, the overlap in performance distributions between healthy participants and MCI individuals at pre-test was reduced at the time of post-test once the ADAFI had been given as intervention. The findings of the present article indicate that plasticity oriented information can be gained when the ADAFI is given as an intervention in a pre-test-training-post-test-design. The cognitive plasticity approach seems potentially useful for purposes of early identification of dementia.

Tensile bond strength of dual curing resin-based cements to commercially pure titanium

OBJECTIVES

The aim of this study was to evaluate the tensile bond strength of dual curing luting resin cements to commercially pure titanium at 10 min and 24h after removal of the oxide layer.

METHODS

One hundred and twenty titanium discs were obtained by casting and polishing with silicon carbide papers. The titanium discs were sandblasted with 50 microm aluminum oxide, ultrasonic cleaned and bonded in pairs with the resin-based cements Panavia F and Rely X ARC at 10 min and 24h after the sandblasting. The tensile test was performed with a crosshead speed of 0.5mm/min in an Instron Universal testing machine.

RESULTS

The Rely X ARC reached the highest tensile strength value at 24h after sandblasting (18.27 MPa), but there was no statistically significant difference between the two dual curing resin cements for both times tested. All specimens showed a mixture of cohesive fracture in the resin cement and adhesive failure. However, the predominant failure mode for Panavia F was cohesive in resin cement, and the Rely X ARC exhibited a greater proportion of specimens with adhesive failure between the alloy and resin luting cement at 10 min and 24h.

SIGNIFICANCE

Both cements had, statistically, the same tensile bond strength. But in the fracture mode analysis, the adhesive predominant fracture mode of Rely X ARC cement indicates a premature clinical adhesive failure. On the other hand, the cohesive predominant fracture mode of Panavia F indicates a longer clinical adhesive bond with titanium.

Clinical features and outcome of pediatric Wegener's granulomatosis

OBJECTIVE

Wegener's granulomatosis (WG) is a predominantly small-vessel vasculitis associated with antineutrophil cytoplasmic antibodies (ANCAs). There are few reports describing its clinical features and outcome in children. We report on the experience at a single tertiary referral center over 21 years.

METHODS

We conducted a retrospective chart review of all patients diagnosed with WG at The Hospital for Sick Children between 1984 and 2005.

RESULTS

Twenty-five patients were identified. Median age at diagnosis and median followup were 14.5 years and 32.7 months, respectively. Male-to-female ratio was 1:4. Median duration of symptoms before diagnosis was 2 months. Of 22 patients, 21 were ANCA positive during their disease course (classic ANCA 78.9%). Constitutional symptoms were the most common clinical feature at presentation (24 of 25). Glomerulonephritis was present in 22 patients at presentation. Only 1 of 11 patients who presented with or developed renal impairment had normalization of serum creatinine. Upper airway involvement occurred in 21 patients at presentation and 24 over followup; only 1 had subglottic stenosis. Twenty patients had initial pulmonary involvement, most commonly nodules (44%) and pulmonary hemorrhage (44%). Five patients required ventilation for pulmonary hemorrhage. Four patients (16%) had venous thrombotic events (VTEs). Treatment included prednisone (100%), cyclophosphamide (76%), azathioprine (40%), and methotrexate (32%).

CONCLUSION

Pediatric WG typically presents in adolescence and has a female predominance. Glomerulonephritis and pulmonary disease are common at diagnosis and frequently present as a pulmonary-renal syndrome. Loss of renal function is common and rarely completely reversible. As in adults, children with WG are at risk of VTEs.

Risk of new-onset uveitis in patients with juvenile idiopathic arthritis treated with anti-TNFalpha agents

OBJECTIVE

To determine whether treatment with tumor necrosis factor alpha (TNFalpha)-blocking agents alters the incidence of new-onset uveitis in patients with juvenile idiopathic arthritis (JIA).

STUDY DESIGN

Cohort study based on retrospective chart review. The charts of all 1109 patients with a diagnosis of JIA seen between January 1, 1996, and June 30, 2003, at our clinic were reviewed for diagnosis of uveitis and treatment with TNFalpha inhibitors. Cox regression analysis was performed with anti-TNFalpha treatment as a time-dependent covariate for risk of development of uveitis.

RESULTS

We identified 70 patients treated with anti-TNFalpha without a prior diagnosis of uveitis. Two of these 70 patients (2.9%), both treated with etanercept, had development of new-onset uveitis during anti-TNFalpha therapy. One had juvenile psoriatic arthritis diagnosed 4.1 years before onset of uveitis. The other had extended oligoarticular JIA diagnosed 6.4 years before onset of uveitis. We found no statistically significant difference in the risk for development of uveitis between patients with or without anti-TNFalpha treatment.

CONCLUSIONS

In our patients with JIA, anti-TNFalpha treatment did not alter the risk for development of new-onset uveitis. However, anti-TNFalpha therapy with etanercept did not prevent the development of uveitis in 2 patients.