bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of B6 vitamin
Authors: Vucijak Nevena , Petrovic Slobodan , Bezbradica Dejan , Knezevic-Jugovic Zorica , Mijin Dusan
Published: October 2009

The importance of vitamin B6 has been known since its discovery in the 1940's. Chemical tests, elestrometric titration determinations, and absorption spectrum studies showed that this vitamin exists in three major chemical forms: pyridoxine (an alcohol), pyridoxal (an aldehyde), and pyridoxamine (a primary amine). Vitamin B6 is needed for more than 100 enzymes involved in protein metabolism, and it is assumed that this vitamin is cofactor of metabolic processes more important than any other substance. A deficiency of vitamin B6 in the human diet leads to severe disorders. Vitamin B6 is necessary for the proper function of the immune and nervous system, and helps the body convert protein to energy. This paper describes the history, properties and applications of vitamin B6, elucidation of chemical structure, and different procedures for synthesis of pyridoxine and pyridoxamine.
Pseudomnas syringae: A pathogen of fruit trees in Serbia
Authors: Gavrilovic Veljko
Published: October 2009

Data about symptomatology, pathogenicity and bacteriological characteristics of Pseudomonas syringae, and PCR methods for fast and reliable detection of the pathogen are given in this paper. P. syringae has been experimentally proved as a pathogen of pear, apple, apricot, plum cherry, and raspberry, and pathogen strains have also been isolated from necrotic peach buds. Two pathogen varieties, syringae and morsprunorum, were found in our research in Serbia, the former being dominant on fruit trees The most reliable method for detection of this bacteria is PCR, using BOX and REP primers. This method has also revealed significant differences among the strains originating from fruit trees in Serbia. Thus, it was proved that the population of P. syringae in Serbia is heterogeneous, which is very important for future epidemiologocal studies. Control of this pathogen includes mechanical, cultural and chemical measures, but integrated approach is very important for sustainable control.
Identification and control of Cladobotryum spp., causal agents of cobeweb disease of cultivated mushroom
Authors: Potocnik Ivana
Published: October 2009

Cladobotryum spp. are causal agents of cobweb disease, one of the most serious diseases of cultivated mushroom (Agaricus bisporus (Lange) Imbach) in Serbia and worldwide, which affects product quality and yield. The disease symptoms are: cottony fluffy white or yellowish to pink colonies on mushroom casing, rapid colonization of casing surface, covering of host basidiomata by mycelia, and their decay. Prochloraz-Mn has been officially recommended for mushroom cultivation in EU countries. However, inefficiency of prochloraz-Mn has been noted at a level of spotting symptoms of cobweb disease. With regard to cases of resistance evolution and a general threat to the environment and human health, special attention should be focused on good programmes of hygiene, and inventing and developing alternative methods of disease control.
A preliminary study of soybean genotype responses to glyphosate
Authors: Marinov-Serafimov Plamen
Published: October 2009

The effect of four application rates of glyphosate (Roundup, 360 g a.i./l) - 180; 360; 720 and 1440 g a.i./ha on the survival, dynamics of growth, and accumulation of fresh biomass in g per plant was studied on eight newly-developed Bulgarian lines, varieties and candidate varieties of soybean bred by different methods under greenhouse conditions. The objective of this study was to determine and compare the sensitivities of different soybean genotypes to glyphosate. The studied soybean genotypes showed different levels of glyphosate sensitivity due to their genetic differences. Glyphosate rates of 180, 360, 720 and 1440 g a.i./ha, applied at the stage of three trifoliate leaves (V4) of soybean had effect on the survival of the studied genotypes and can be presented conditionally in the following order: H (40.6%) < G (40.7%) < D (51.3%) < C (52.6%) < F (58.9%) < E (60.5%) < B (62.0%) < A (65.3%). The depression coefficients (B) of the studied characteristics depended mainly on soybean genotypes and the applied herbicide rates. The tested glyphosate rates showed a high (GI 26.5-51.6%) to relatively low degree of toxicity (GI 16.0-18.7%) in the studied soybean genotypes.
Prediction of Coronary Heart Disease Risk in a General, Pre-Diabetic, and Diabetic Population During 10 Years of Follow-up: Accuracy of the Framingham, SCORE, and UKPDS Risk Functions
Authors: van der Heijden Amber A.W.A. , Ortegon Monica M. , Niessen Louis W. , Nijpels Giel , Dekker Jacqueline M.
Published: October 2009

OBJECTIVE

To test the validity of the Framingham, Systematic Coronary Risk Evaluation (SCORE), and UK Prospective Diabetes Study (UKPDS) risk function in the prediction of risk of coronary heart disease (CHD) in populations with normal glucose tolerance (NGT), intermediate hyperglycemia, and type 2 diabetes.

RESEARCH DESIGN AND METHODS

Calibration and discrimination of the three prediction models were tested using prospective data for 1,482 Caucasian men and women, 50–75 years of age, who participated in the Hoorn Study. All analyses were stratified by glucose status.

RESULTS

During 10 years of follow-up, a total of 197 CHD events, of which 43 were fatal, were observed in this population, with the highest percentage of first CHD events in the diabetic group. The Framingham and UKPDS prediction models overestimated the risk of first CHD event in all glucose tolerance groups. Overall, the prediction models had a low to moderate discriminatory capacity. The SCORE risk function was the best predictor of fatal CHD events in the group with NGT (area under the receiver operating characteristic curve 0.79 [95% CI 0.70–0.87]), whereas the UKPDS performed better in the intermediate hyperglycemia group (0.84 [0.74–0.94]) in the estimation of fatal CHD risk. After exclusion of known diabetic patients, all prediction models had a higher discriminatory ability in the group with diabetes.

CONCLUSIONS

The use of the Framingham function for prediction of the first CHD event is likely to overestimate an individual's absolute CHD risk. In CHD prevention, application of the SCORE and UKPDS functions might be useful in the absence of a more valid tool.
Autologous Umbilical Cord Blood Transfusion in Very Young Children With Type 1 Diabetes
Authors: Haller Michael J. , Wasserfall Clive H. , McGrail Kieran M. , Cintron Miriam , Brusko Todd M. , Wingard John R. , Kelly Susan S. , Shuster Jonathan J. , Atkinson Mark A. , Schatz Desmond A.
Published: October 2009

OBJECTIVE

Interest continues to grow regarding the therapeutic potential for umbilical cord blood therapies to modulate autoimmune disease. We conducted an open-label phase I study using autologous umbilical cord blood infusion to ameliorate type 1 diabetes.

RESEARCH DESIGN AND METHODS

Fifteen patients diagnosed with type 1 diabetes and for whom autologous umbilical cord blood was stored underwent a single intravenous infusion of autologous cells and completed 1 year of postinfusion follow-up. Intensive insulin regimens were used to optimize glycemic control. Metabolic and immunologic assessments were performed before infusion and at established time periods thereafter.

RESULTS

Median (interquartile range [IQR]) age at infusion was 5.25 (3.1–7.3) years, with a median postdiagnosis time to infusion of 17.7 (10.9–26.5) weeks. No infusion-related adverse events were observed. Metabolic indexes 1 year postinfusion were peak C-peptide median 0.50 ng/ml (IQR 0.26–1.30), P = 0.002; A1C 7.0% (IQR 6.5–7.7), P = 0.97; and insulin dose 0.67 units · kg−1 · day−1 (IQR 0.55–0.77), P = 0.009. One year postinfusion, no changes were observed in autoantibody titers, regulatory T-cell numbers, CD4-to-CD8 ratio, or other T-cell phenotypes.

CONCLUSIONS

Autologous umbilical cord blood transfusion in children with type 1 diabetes is safe but has yet to demonstrate efficacy in preserving C-peptide. Larger randomized studies as well as 2-year postinfusion follow-up of this cohort are needed to determine whether autologous cord blood–based approaches can be used to slow the decline of endogenous insulin production in children with type 1 diabetes.
Self-Monitoring of Blood Glucose as Part of the Integral Care of Type 2 Diabetes
Authors: Boutati Eleni I. , Raptis Sotirios A.
Published: October 2009

Results from landmark diabetes studies have established A1C as the gold standard for assessing long-term glycemic control. However, A1C does not provide “real-time” information about individual hyperglycemic or hypoglycemic excursions. Real-time information provided by self-monitoring of blood glucose (SMBG) represents an important adjunct to A1C, because it can differentiate fasting, preprandial, and postprandial hyperglycemia; detect glycemic excursions; identify hypoglycemia; and provide immediate feedback about the effect of food choices, physical activity, and medication on glycemic control. The importance of SMBG is widely appreciated and recommended as a core component of management in patients with type 1 or insulin-treated type 2 diabetes, as well as in diabetic pregnancy, for both women with pregestational type 1 and gestational diabetes. Nevertheless, SMBG in management of non–insulin-treated type 2 diabetic patients continues to be debated. Results from clinical trials are inconclusive, and reviews fail to reach an agreement, mainly because of methodological problems. Carefully designed large-scale studies on diverse patient populations with type 2 diabetes with the follow-up period to investigate long-term effects of SMBG in patients with type 2 diabetes should be carried out to clarify how to make the best use of SMBG, in which patients, and under what conditions.
Infant Anaplastic Large Cell Lymphoma with Hemophagocytic Syndrome
Authors: Khor Tze S. , Alessandri Angela J. , Jevon Gareth P.
Published: October 2009

Anaplastic large cell lymphoma (ALCL), anaplastic lymphoma kinase (ALK)-positive, is uncommon in infancy. We present an unusual occurrence of infant ALCL, ALK-positive, associated with hemophagocytic syndrome. To the best of our knowledge, there have been no cases of infant ALCL, ALK-positive, described that have been associated with hemophagocytic syndrome. Particularly in this age group, primary hemophagocytic syndrome is also a consideration, which raises particular differential diagnostic considerations.
The solution existence and convergence analysis for linear and nonlinear differential-operator equations in Banach spaces within the Calogero type projection-algebraic scheme of discrete approximations
Authors: Lustyk Miroslaw , Janus Julian , Pytel-Kudela Marzenna , Prykarpatsky Anatoliy
Published: October 2009

The projection-algebraic approach of the Calogero type for discrete approximations of linear and nonlinear differential operator equations in Banach spaces is studied. The solution convergence and realizability properties of the related approximating schemes are analyzed. For the limiting-dense approximating scheme of linear differential operator equations a new convergence theorem is stated. In the case of nonlinear differential operator equations the effective convergence conditions for the approximated solution sets, based on a Leray-Schauder type fixed point theorem, are obtained.
A note on a Brill-Noether locus over a non-hyperelliptic curve of genus 4
Authors: Huh Sukmoon
Published: October 2009

We prove that a certain Brill-Noether locus over a non-hyperelliptic curve C of genus 4, is isomorphic to the Donagi-Izadi cubic threefold in the case when the pencils of the two trigonal line bundles of C coincide.
Positive and maximal positive solutions of singular mixed boundary value problem
Authors: Agarwal Ravi , O’Regan Donal , Staněk Svatoslav
Published: October 2009

The paper is concerned with existence results for positive solutions and maximal positive solutions of singular mixed boundary value problems. Nonlinearities h(t;x;y) in differential equations admit a time singularity at t=0 and/or at t=T and a strong singularity at x=0.
X/XY Chromosome Mosaicism: Turner Syndrome and Other Clinical Conditions
Authors: Andriuškevičiūtė Irena , Šalomskienė Loreta , Jurkėnienė Lina , Sinkus Algimantas
Published: October 2009

X/XY Chromosome Mosaicism: Turner Syndrome and Other Clinical Conditions

The 45,X/46,XY mosaicism shows a wide spectrum of phenotypes ranging from females with Turner syndrome, male or female pseudohermaphroditism, to appearently normal male development. Chromosome anomalies accompanying Turner syndrome were found in lymphocyte cultures of 236 patients. Chromosomal analysis revealed the karyotype 45,X in 118 (50.0%) patients. X monosomy mosaics or structural rearrangements of the X chromosome was established in 112 (47.5%) patients. The Y chromosome was found in six (2.5%) patients with typical features of Turner syndrome. In five mosaics 45,X/46,XY the proportion of the XY clone ranged from 46% to 76%. In one Turner syndrome patient only 47,XYY cells were found (solely blood culture investigated). In most cases of 45,X/46,XY mosaicism, the cause is considered to be the loss of the Y chromosome because of nondisjunction after normal disomic fertilisation. Five other patients with X/XY chromosome mosaicism showed mixed gonadal dysgenesis (two patients), one male pseudohermafroditism, one male with Pierre Robin syndrome, and one normal male phenotype. In two non Turner syndrome patients nondisjunction of the primary clone 46,XY was obvious and resulted in mosaicism 45,X/46,XY/47,XYY, the one patient contained dicentric Y. The similarities between X/XY Turner syndrome and other nosological entity of females possessing Y chromosome — the Swyer syndrome — are discussed.
An Approach to Teaching Animal Welfare Issues at The Ohio State University
Authors: Lord Linda K. , Walker Jennifer B.
Published: October 2009

Despite the growing importance of animal welfare and the critical role of the veterinary profession, animal welfare is not formally taught in many veterinary curricula. In addition, veterinary students are often not exposed to current contentious animal welfare issues, which are subject to much debate and often proposed regulation. To address this deficiency in our curriculum at The Ohio State University College of Veterinary Medicine, we have developed a course titled “Contemporary Issues in Animal Welfare.” Our specific objectives for the course are: 1) to provide students with the opportunity to objectively evaluate and discuss current issues in the welfare of animals as companions, and in the industries of agriculture, science, education, conservation, and entertainment; 2) to increase students’ awareness of current important animal welfare issues; and 3) to develop students’ skills in the critical evaluation of written and visual material used in the scientific literature and lay press. We hope that, over time, this teaching model will be considered a means to educate veterinary students about animal welfare issues in other veterinary curricula.
Successful aging as an oxymoron
Authors: Torres Sandra , Hammarström Gunhild
Published: October 2009

Notions of what it means to age well or successfully are central to social gerontological research and practice. As such, one would expect that there would be consensus as to what the construct of successful aging means and/or how aging well is achieved. This is not, however, the case which is why this study explores the meanings that a group of older people (i.e. some with home-help care and some without) attach to this construct. The empirical material is constituted of 16 semi-structured interviews. The findings bring to fore the different resources (such as physical, mental, psycho-social, spiritual, and financial ones) that are associated with successful aging and the kind of outlook on life that is regarded as useful if one wants to age well. Differences between home-help care recipients and those that do not receive this type of care were found. Those that are managing without the help offered by home-help care services listed more resources and offered more nuanced descriptions of what successful aging means than those that receive home- help care. This suggests that receiving home-help care and/or not being able to manage primarily on one’s own might shape the manner in which older people think about what constitutes a good old age. The in-depth analysis of the notions of successful aging that were brought to the fore suggests also the paradoxical fact that the title of this article attests to; namely that some associate aging well with not aging at all and deem, in fact, the term successful aging to be an oxymoron.
Living in single person households and the risk of isolation in later life
Authors: Hill Michael , Banks Laura , Haynes Philip
Published: October 2009

Data from the International Social Survey Programme (2001) was used to analyse the social networks of older people and whether living in single person households increased the risk of isolation. When comparing respondents with one or more adult children, there was no significant difference in the likelihood of experiencing familial isolation between people living in single person households and those living in larger households. A majority of those living in single person households had at least regular contact with a sibling, adult child or close friend and participated in a social organisation. Friends compensate to some extent for a lack of support from the family, although in southern and eastern European countries, other relatives appeared to be more important in support networks. People living in single person households were more likely to experience isolation, but this was largely related to advanced age and childlessness. Whilst a very small minority in Japan were living in single person households, they were significantly more likely to be severely isolated than those living in single person households in other countries.
Configurational Entropy in Chiral Solutions—Negative Entropy of Solvent Envelopes
Authors: Shinitzky Meir
Published: October 2009

A homogeneous solution of a chiral substance is acquired with an overall asymmetry which is expressed by a specific rotation of a linearly polarized light. Such a solution, despite being at a complete equilibrium, stores configurational entropy in a form of negative entropy which can be nullified by mixing with a solution of the opposite enantiomer. This abundant, yet quite a specific case of inherent negative entropy, resides predominantly in the chiral configuration of the solvent envelopes surrounding the chiral centers. Heat release, amounting to several cal/mol, associated with the annulment of negative entropy in aqueous solutions of D- and L-amino acids, was recently documented by Shinitzky et al. [1]. This heat corresponds almost exclusively to TΔS stored in the solvent envelope upon adoption of a chiral configuration. Simple fundamental expressions which combine configurational entropy and information capacity in chiral solutions have been developed and were found to comply well with the observed heat release upon intermolecular racemization.
Distributed Environment Control Using Wireless Sensor/Actuator Networks for Lighting Applications
Authors: Nakamura Masayuki , Sakurai Atsushi , Nakamura Jiro
Published: October 2009

We propose a decentralized algorithm to calculate the control signals for lights in wireless sensor/actuator networks. This algorithm uses an appropriate step size in the iterative process used for quickly computing the control signals. We demonstrate the accuracy and efficiency of this approach compared with the penalty method by using Mote-based mesh sensor networks. The estimation error of the new approach is one-eighth as large as that of the penalty method with one-fifth of its computation time. In addition, we describe our sensor/actuator node for distributed lighting control based on the decentralized algorithm and demonstrate its practical efficacy.
Super-Resolution Reconstruction of Remote Sensing Images Using Multifractal Analysis
Authors: Hu Mao-Gui , Wang Jin-Feng , Ge Yong
Published: October 2009

Satellite remote sensing (RS) is an important contributor to Earth observation, providing various kinds of imagery every day, but low spatial resolution remains a critical bottleneck in a lot of applications, restricting higher spatial resolution analysis (e.g., intraurban). In this study, a multifractal-based super-resolution reconstruction method is proposed to alleviate this problem. The multifractal characteristic is common in Nature. The self-similarity or self-affinity presented in the image is useful to estimate details at larger and smaller scales than the original. We first look for the presence of multifractal characteristics in the images. Then we estimate parameters of the information transfer function and noise of the low resolution image. Finally, a noise-free, spatial resolutionenhanced image is generated by a fractal coding-based denoising and downscaling method. The empirical case shows that the reconstructed super-resolution image performs well indetail enhancement. This method is not only useful for remote sensing in investigating Earth, but also for other images with multifractal characteristics.
A Topology Reorganization Scheme for Reliable Communication in Underwater Wireless Sensor Networks Affected by Shadow Zones
Authors: Domingo Mari  Carmen
Published: October 2009

Effective solutions should be devised to handle the effects of shadow zones in Underwater Wireless Sensor Networks (UWSNs). An adaptive topology reorganization scheme that maintains connectivity in multi-hop UWSNs affected by shadow zones has been developed in the context of two Spanish-funded research projects. A mathematical model has been proposed to find the optimal location for sensors with two objectives: the minimization of the transmission loss and the maintenance of network connectivity. The theoretical analysis and the numerical evaluations reveal that our scheme reduces the transmission loss under all propagation phenomena scenarios for all water depths in UWSNs and improves the signal-to-noise ratio.
Antagonism of Innate Immunity by Paramyxovirus Accessory Proteins
Authors: Chambers Raychel , Takimoto Toru
Published: October 2009

Paramyxovirinae, a subfamily of Paramyxoviridae, are negative strand RNA viruses comprised of many important human and animal pathogens, which share a high degree of genetic and structural homology. The accessory proteins expressed from the P/V/C gene are major factors in the pathogenicity of the viruses, because of their ability to abrogate various facets of type I interferon (IFN) induction and signaling. Most of the paramyxoviruses exhibit a commonality in their ability to antagonize innate immunity by blocking IFN induction and the Jak/STAT pathway. However, the manner in which the accessory proteins inhibit the pathway differs among viruses. Similarly, there are variations in the capability of the viruses to counteract intracellular detectors (RNA helicases, mda-5 and RIG-I). Furthermore, a functional specificity in the antagonism of the IFN response has been reported, suggesting that specificity in the circumvention of innate immunity restricts viral host range. Available evidence indicates that paramyxoviruses employ specific strategies to antagonize the IFN response of their specific hosts, which is one of the major factors that determine viral pathogenicity and host range.
Retinopathy of Prematurity and Shaken Baby Syndrome
Authors: Aziz Hassan A. , Berrocal Audina , Sisk Robert , Murray Timothy
Published: October 2009

Retinopathy of prematurity is a vasoproliferative disease that occurs mostly in premature and low birth weight neonates. It is a potentially blinding disease that should be screened vigorously. On the other hand, shaken baby syndrome is a non-accidental trauma that is both common and avoidable. Ophthalmologists play a crucial role in diagnosing and treating the shaken infant. The authors describe a child with the combination of retinopathy of prematurity and shaken baby syndrome.
Cut and Paste: Sutureless Conjunctival Closure in Strabismus Surgery
Authors: Guo Suqin , Wagner Rudolph S. , Forbes Brian J. , Derespinis Patrick A. , Caputo Anthony R.
Published: October 2009

Purpose:

This study investigated the use of fibrin glue and compared its effect with traditional sutures for conjunctival closure in strabismus surgery.

Methods:

The study included 12 patients undergoing horizontal strabismus surgery, of whom 5 underwent bilateral medial rectus muscle recessions and 7 underwent bilateral lateral rectus muscle recessions. For each patient, fibrin glue was used to close the conjunctiva of one eye and 6-0 plain sutures were used to close the other.

Results:

All eyes maintained adequate closure of the conjunctiva postoperatively and there were no intraoperative or postoperative complications for any eye. However, the average surgical time needed to apply fibrin glue was considerably less than that required for closure with sutures. Furthermore, eyes closed with fibrin glue were associated with significantly less postoperative inflammation and patient discomfort than those closed with sutures. All patients and parents reported significantly less discomfort from the eyes treated with fibrin glue.

Conclusion:

These results are promising and demonstrate a safe and effective alternative to traditional suture closure in strabismus surgery. When compared to traditional suture closure, conjunctival closure with glue includes the following advantages: less postoperative patient discomfort, diminished postoperative inflammation, and potentially reduced surgical time with corresponding reduced time under general anesthesia.
Macular Abnormality Observed by Optical Coherence Tomography in Children With Amblyopia Failing to Achieve Normal Visual Acuity After Long-Term Treatment
Authors: Liu Hong , Zhong Lu , Zhou Xin , Jin Qing-Zi
Published: October 2009

EDUCATIONAL OBJECTIVES

1.

To explore whether there is any explanation for children with amblyopia who fail to achieve normal visual acuity.

2.

To discuss the optical coherence tomography application in observing the macular abnormality in children with amblyopia.

3.

To diagnose and evaluate the potential curable effect on treatment of amblyopia using optical coherence tomography examination.

Purpose:

To investigate why some children with amblyopia fail to achieve normal visual acuity.

Methods:

Optical coherence tomography (OCT) was performed to observe the morphology of the macular tissue of children with various types of amblyopia who failed to achieve normal visual acuity (⩽ 20/25). Average thickness of the retinal nerve fiber layer (RNFL) of the foveola and fovea (1-mm diameter range) was then assessed by macular retinal tomography map measurement. The data obtained were compared with those considered normal to detect any abnormality.

Results:

Fifteen patients (24 eyes) were examined. Images showed abnormality with thickened RNFL in the macular area in which either the fovea was not observed or the wave lines were flattened or unformed. The average RNFL thickness measured 201.5 ± 17.9 µm for the foveola and 226.9 ± 11.4 µm for the fovea (1-mm diameter range). The differences were highly statistically significant compared with normal values. Five cases were ametropic amblyopia, 5 were anisometropic amblyopia, and 5 were idiopathic amblyopia. Eleven cases showed improvement and 4 cases showed no response to the treatment. Twelve cases were myopic, 1 was mixed astigmatism, and 2 were normal. Nine cases were binocular amblyopia and 6 cases were uniocular amblyopia.

Conclusion:

Some children with various types of amblyopia who failed to achieve normal visual acuity after treatment showed macular abnormality on OCT examination.

[J Pediatr Ophthalmol Strabismus 2010;47:17–23.]
Is Buckle Surgery Still the State of the Art for Retinal Detachments Due to Retinal Dialysis?
Authors: Stoffelns Bernhard M. , Richard Gisbert
Published: October 2009

Purpose:

Retinal dialysis is a frequent cause of retinal detachment in infants and young adults. The authors report long-term results obtained with conventional detachment surgery in a large consecutive series.

Methods:

Fifty-two eyes of 50 patients with retinal detachment due to dialysis underwent a segmental buckling procedure between January 1990 and December 1998. Patient characteristics and surgical results at 1 year of follow-up were evaluated. In 2007, 40 eyes from these groups were reexamined for long-term results (follow-up: 9 to 17 years; median: 13.4 years).

Results:

The mean age of the patients was 12.8 years (range = 6 to 28 years). Preferred locations of the dialyses were inferotemporal (72%) and superonasal (16%). The macula was detached in 82%. At 1 year of follow-up, the retina was completely reattached after one surgical procedure in 87% and after two procedures in 97%. Long-term follow-up of 40 of 52 eyes revealed no retinal redetachment, but additional surgeries had been performed. Visual acuity improved in 70% of the eyes, but only 40% reattained reading vision due to the high rate of macula-off retinal detachment preoperatively.

Conclusion:

Scleral buckling for retinal detachment due to dialysis yields good results, even in the long term, and remains the treatment of choice for these usually young patients despite the increasing popularity of primary vitrectomy.
Copper In-Depth Distribution in Hydrogen Implanted Cz Si Wafers Subjected to Two-Step Annealing
Authors: Frantskevich A.V. , Fedotov A.K. , Mazanik A.V. , Frantskevich N.V.
Published: October 2009

In this work we have studied the in-depth distribution of copper deposited on the surface of the hydrogen pre-implanted Cz Si wafers depending on the conditions of their subsequent annealing. In the standard n-type 4.5 ∙cm Cz Si wafers different numbers of radiation defects were formed by hydrogen ion implantation with an energy of 100 keV (0.9 m projected range, Rp) for different fluences (11015, 11016, or 41016 at/cm2) at room temperature. Then a copper layer 50-nm thick was deposited on the sample surface by magnetron sputtering at temperatures 250 or 300 oC with subsequent annealing for 4 h at the same temperatures. Whereupon the surface was chemically etched and the samples were annealed in vacuum during 2 h at 700 oC. The depth profiles of copper in the near-surface layer were controlled by RBS investigations both in the random and channeling modes. These experiments have shown that the copper in-depth distribution strongly depends on the implantation fluence and temperature of the low-temperature annealing: in case of copper deposition at 250 oC a relatively strong peak determined by copper on the surface is observed in RBS spectra after all the above-described steps. On the contrary, for higher temperatures of copper deposition (300 oC) a significant decrease in the intensity of this peak is observed in RBS spectra. A maximal concentration of copper at a depth of the projected range, Rp, was observed for the samples implanted with a maximal fluence (41016 at/cm2).
Review of Stress Effects on Dopant Solubility in Silicon and Silicon-Germanium Layers
Authors: Bennett Nicholas S. , Ahn Chihak , Cowern Nicholas E.B. , Pichler Peter
Published: October 2009

We present a review of both theoretical and experimental studies of stress effects on the solubility of dopants in silicon and silicon-germanium materials. Critical errors and limitations in early theory are discussed, and a recent treatment incorporating charge carrier induced lattice strain and correct statistics is presented. Considering all contributing effects, the strain compensation energy is the primary contribution to solubility enhancement in both silicon and silicon-germanium for dopants of technological interest. An exception is the case of low-solubility dopants, where a Fermi level contribution is also found. Explicit calculations for a range of dopant impurities in Si are presented that agree closely with experimental findings for As, Sb and B in strained Si. The theoretical treatment is also applied to account for stress effects in strained SiGe structures, which also show close correlation with recently derived experimental results for B-doped strained SiGe which are presented here for the first time.
Thermal Optimization of Cz Silicon Single Crystal Growth
Authors: Prostomolotov A.I. , Verezub N.A. , Milvidskii M.G.
Published: October 2009

In an application to large diameter Czochralski (CZ) silicon (Si) single crystal growing the influence on crystal temperature field of various thermal shield assemblies located near to its surface is discussed. By means of mathematical modeling the computer model of thermal processes in an application to a hot zone of "Redmet-90" puller [1], intended for 200 and 300 mm diameter Si single crystal growth is developed. The role of the ring shield and the shield assembly, consisting of two shields (an internal cone and an external one is repeating the crucible shape) and being as a basis of some patents, is investigated. On the basis of the carried out calculations the new thermal shield assembly for "Redmet-90" puller was offered. Its influence on formation of the characteristic thermal zones in growing single crystal, corresponding to defect formation processes in dislocation-free Si crystals (the recombination of intrinsic point defect – IPD, and the formation of their agglomerates) is discussed. The influence of a melt flow on the liquid/solid interface (LSI) shape and thermal stability of crystal growing process is analyzed.
Simulation of Iron Distribution after Crystallization of mc Silicon
Authors: Schön Jonas , Habenicht Holger , Schubert Martin C. , Warta Wilhelm
Published: October 2009

Interstitial iron (Fei) and iron-boron pairs influence or even limit the recombination lifetime in industrial block cast multicrystalline (mc) silicon, though the proportions in the total iron concentration are generally small. Most of the iron in mc silicon is precipitated and less recombination active. This work aims for a better understanding of the distribution of iron in its different states (precipitated or dissolved) over the block height, as well as in regions of different crystal quality. In experimental studies several features of iron in mc silicon were observed, which occur due to the high extended defect density. In our 2-dimensional model for mc silicon, trapping of interstitial Fe at extended defects and precipitation at the extended defects are taken into account. The results are compared with NAA-data and spatial resolved measurements of the Fei concentration.
Comparison of Efficiency and Kinetics of Phosphorus-Diffusion and Aluminum Gettering of Metal Impurities in Silicon: a Simulation study
Authors: Falkenberg M.A. , Abdelbarey D. , Kveder Vitaly V. , Seibt Michael
Published: October 2009

The efficiency of solar cells produced from crystalline silicon materials is considerably affected by the presence of metal impurities. In order to reduce the concentration of metal impurities, gettering processes as phosphorus diffusion gettering (PDG) and aluminum gettering (AlG) are routinely included in solar cell processing. Further development and optimization of gettering schemes has to ground on physics-based simulations of gettering processes. In this contribution we use quantitative simulations to compare the efficiency and kinetics of PDG and AlG in the presence of precipitates for interstitially dissolved metals, like iron, at different gettering conditions. Recently measured segregation coefficients of iron in liquid AlSi with respect to crystalline silicon are used in order to compare with PDG under typical conditions. It is shown that kinetics of both, PDG and AlG, can be separated into two regimes: (i) at low temperatures kinetics are limited by precipitate dissolution, and (ii) at high temperatures kinetics of AlG is mainly limited by metal impurity diffusion while phosphorus in-diffusion is the limiting factor of PDG.
Effect of Growth Conditions and Catalyst Material on Nanowhisker Morphology: Monte Carlo Simulation
Authors: Nastovjak A.G. , Neizvestny I.G. , Shwartz Nataly
Published: October 2009

The process of nanowhisker formation on the substrates activated by catalyst drops was investigated by Monte Carlo simulation. Influence of deposition conditions on whisker morphology was considered. Straight whiskers with uniform diameter could be grown using catalyst possessing large contact angle with whisker material. It was demonstrated that variation of growth conditions in such physicochemical system may result in nanotube formation. Atomic mechanism of hollow whisker formation was suggested. The range of model growth conditions for nanowhisker and nanotube formation were identified.
Versatile Simulation Tool and Novel Measurement Method for Electrical Characterization of Semiconductors
Authors: Schüler N. , Hahn Torsten , Dornich Kay , Niklas J.R.
Published: October 2009

A versatile numerical tool for the simulation of electrical properties of a semiconductor
such as minority carrier lifetimes and photoconductivity as a function of defect parameters was developed.
Unlike the SRH-model this tool enables to simulate e.g. different measurement conditions
and even trapping effects. Contrary to the widely used simulation tool PC1D also non-steady state
solutions can be obtained. Furthermore the novel contact less method MDP is presented. Using the
example of iron determination the new possibilities arising from combining the novel simulation
tool and the method MDP are shown. Simulations for different trapping densities and measurement
conditions were executed and exemplary measurements of the trap density and the cross-over point
of mc-Si wafers were performed. It was found, that the cross-over point and the sensitivity of iron
determination at low level injections is effected by trapping and the chosen non- or steady state
measurement conditions.
Analysis of Heterogeneous Iron Precipitation in Multicrystalline Silicon
Authors: Haarahiltunen Antti , Vähänissi Ville , Yli-Koski Marko , Talvitie H. , Savin Hele
Published: October 2009

Iron precipitation in multicrystalline silicon has been modeled aiming at the optimization of intrinsic gettering of iron in multicrystalline silicon. Iron precipitation during both crystal growth and following phosphorus diffusion gettering (PDG) are simulated and compared to experimental results as the iron precipitate density after these processes is essential in the modeling of intrinsic gettering in multicrystalline silicon solar cell processing. The PDG decreases the density of iron precipitates compared to the as-grown state and as expected the effect is larger at lower initial iron concentrations. Due to this effect the iron precipitation is significantly reduced almost throughout the whole ingot height and it can be concluded that intrinsic gettering has a beneficial effect only in the case of high initial iron concentration, in accordance with the experimental results. The simulated change in interstitial iron concentration as a function of intrinsic gettering temperature suggests the same optimum intrinsic gettering temperature as the experiments. With the given model it is however much easier to find optimal parameters compared to expensive and time consuming experiments.
Dislocation States and Deformation-Induced Point Defects in Plastically Deformed Germanium
Authors: Shevchenko S. , Tereshchenko A.N.
Published: October 2009

We used the DLTS and photoluminescence (PL) techniques to study the deep states due to dislocations and deformation-induced point defects (PDs) in plastically deformed p-type germanium single crystals containing predominantly 60 dislocations with density ND, ranging from 105 to 106 cm-2. The narrow line near the temperature 140K dominates in the DLTS spectra. The ionization enthalpy and the capture cross section for holes traps indicate that the substitution copper atoms Cus are the main type of PDs. A decrease of the Cus atoms concentration and redistribution of the intensity in the PL spectra after the heat treatment of deformed samples at a temperature 500 °C are attributed to the diffusion of copper atoms to dislocations resulting in the appearance of “dirty” regular segments of 60 dislocations.
Formation of Radiation-Induced Defects in Si Crystals Irradiated with Electrons at Elevated Temperatures
Authors: Markevich Vladimir P. , Peaker Anthony R. , Lastovskii Stanislav B. , Gusakov Vasilii E. , Medvedeva I.F. , Murin L.I.
Published: October 2009

Defects induced in silicon crystals by irradiations with 6 MeV electrons in the temperature range 60 to 500 oC have been studied by means of deep level transient spectroscopy (DLTS) and high-resolution Laplace DLTS. Diodes for the study were fabricated on n-type epitaxially grown Si wafers. The DLTS spectra for the samples irradiated at elevated temperatures were compared with those for samples, which were subjected to irradiation at 60 oC and subsequent isochronal anneals in a furnace. The dominant radiation-induced defects in the samples irradiated at temperatures lower than 400 oC were found to be vacancy-oxygen (VO) and interstitial carbon – interstitial oxygen (CiOi) complexes. The introduction rates of the VO and CiOi centers increased about twice upon raising the irradiation temperature from 50 to 400 oC. It is argued that this effect is associated with either a) the suppression of the annihilation rate of Frenkel pairs or b) a decrease in the threshold energy for displacement of a host Si atom upon increase in the irradiation temperature. Transformations of deep level traps due to divacancies (V2) and trivacancies (V3) to V2-oxygen and V3-oxygen complexes were found to occur upon irradiation or annealing at temperatures exceeding 250 oC. A clear anti-correlation between changes in the minority carrier life time induced in the p+-n diodes by irradiation at different temperatures and changes in the concentrations of radiation-induced vacancy- and vacancy-oxygen-related complexes was found.
Suppression of Pores Formation on a Surface of p-Si by Laser Radiation
Authors: Medvid Arthur , Onufrijevs Pavels , Fedorenko L. , Yusupov N. , Dauksta Edvins
Published: October 2009

The influence of strongly absorbing N¬2 laser radiation on pores formation on a surface of Si single crystal has been investigated using optical microscope, atomic force microscope and photoluminescence. After irradiation by the laser and subsequent electrochemical etching in HF acid solution morphological changes of the irradiated parts of a surface of Si were not observed. At the same time, pores formation on the non-irradiated parts of Si surface took place. The porous part of the Si surface is characterized by strong photoluminescence in red part of spectra with maximum at 1.88 eV and intensity of photoluminescence increases with current density. Suppression of the pores formation by the laser radiation is explained with inversion of Si type conductivity from p-type to n-type. This fact is explained by Thermogradient effect – generation and redistribution of the intrinsic defects in gradient of temperature. It was shown that the depth of n-Si layer on p-Si substrate depends on intensity of laser radiation and it increases with intensity of laser radiation. The results of the investigation can be used for optical recording and storage of information on surface of semiconductors.
Hydrogen-Induced Passivation of Grain-Boundary Defects in Polycrystalline Silicon
Authors: Nickel N.H.
Published: October 2009

The influence of the hydrogen content in the amorphous starting material on hydrogen bonding and defect passivation in laser annealed polycrystalline silicon is investigated. The samples are characterized using electron paramagnetic resonance and hydrogen effusion measurements. After laser dehydrogenation and crystallization the samples contain a residual H concentration of up to 8×1021 cm-3. During a vacuum anneal at least 1.5×1021 cm-3 are mobile of which only 3.7×1018 cm-3 H atoms passivate preexisting Si dangling bonds. It is shown that a vacuum anneal can cause the vast majority of H atoms to accumulate in platelet-like structures. Defect passivation and platelet nucleation and growth occur spatially separated requiring long range H diffusion.
Characterization of Thin Film Photovoltaic Material Using Photoluminescence and Raman Spectroscopy
Authors: Mchedlidze Teimuraz , Arguirov Tzanimir , Kouteva-Arguirova Simona , Kittler Martin
Published: October 2009

Electrical and structural properties of thin-film photovoltaic (PV) material fabricated using Crystal Silicon on Glass (CSG) technology was investigated applying photoluminescence (PL) and Raman spectroscopy (RS). The obtained results and their correlation with the PV properties of the cells prepared from the same material showed that PL is applicable for in-line characterization of the material before the electrical contact fabrication processes. The results obtained using RS gave useful information on crystallization grade of the material during the fabrication process.
Delineation of Microdefects in Silicon Substrates by Chromium-Free Preferential Etching Solutions and Laser Scattering Tomography
Authors: Pellowska M. , Possner D. , Kot D. , Kissinger G. , Kolbesen Bernd O.
Published: October 2009

Chromium-free preferential etching techniques in combination with light optical microscopy were compared with the non-destructive Laser Scattering Tomography (LST) for the evaluation of crystal defect densities in Czochralski substrates grown under different conditions. Dichromate containing etching solutions (original Secco etch and dilute Secco etch) were included into the study as reference. The chromium-free etching solutions with high etch rates comprised mixtures of nitric, hydrofluoric and acetic acid with water (JEITA 1, MEMC). Those with low etch rates consisted of mixtures of nitric and acetic or propanoic acid with hydrogen peroxide which form peracetic or perpropanoic acid (Organic Peracid Etches). OPE solutions provide improved discrimination of different types of defects and work also on highly doped substrates. As a general result, it turned out that the defect densities determined by the preferential etching solutions applied were significantly higher than those evaluated by LST. Relatively close to the LST defect densities are those determined by original Secco etch for larger etch pits.
An Express Method for the Study of Planar Homogeneity of Diffusion Lenght in Multicrystalline Solar Silicon
Authors: Litovchenko V.G. , Sarikov Andrey V. , Evtukh A.A.
Published: October 2009

In this paper, the influence of the gettering treatment on the distribution of diffusion length of minority charge carriers in multicrystalline silicon has been investigated. For the calculation of the parameters of diffusion length distribution, a new method has been proposed based on the mathematical treatment of experimentally measured integrated spectra of surface photovoltage measured by capacitor method (capacitor photovoltage). Obtained results show not only the increase of the average diffusion length as a result of used gettering procedure, but also the decrease of inhomogeneity of its distribution.