bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identifying the Root Cause of Drilling Vibration and Stick-Slip Enables Fit-for-Purpose Solutions
Authors: Wu Xianping , Karuppiah Venki , Nagaraj Mahavir , Partin Uyen , Machado Marcia , Franco Mariana , Duvvuru Hari 
Published: April 2012

Abstract
Severe vibration and stick-slip are devastating dysfunctions that significantly limit drilling performance. They cause equipment failure and increase non-productive time driving up field development costs. The evolution of real-time downhole measurement technologies can monitor the onset and severity of vibrations and stick-slip. However, the low-frequency of the measurement data and increasing BHA complexity, the information does not necessarily pinpoint the root cause of drilling dysfunction. Drillers are often forced to live with the trial-and-error process to mitigate vibrations/stick-slip, which is an expensive and inefficient approach.
Combining the engineering expertise with an advanced drilling dynamics model, the service provider has successfully identified the root cause of vibration and stick-slip in a number of challenging drilling applications worldwide. This enables engineers to concentrate on fit-for-purpose solutions rather than the traditional trial-and-error approach.Two case studies are discussed to outline and document the analysis process and the underlying solution technologies.
Case study-1: drilling a 16” section in a Middle East gas field through heavily interbedded formations with hard stringers was damaging project economics. The root cause of damage was identified as bit whirl and axial vibration. The PDC was redesigned to improve durability and achieved the longest 16” run in this field with ROP 18% faster than the best offset.
Case study-2: hole enlargement while drilling a 17½” x 20” section offshore Brazil was challenging due to hard and abrasive formations. Premature reamer cutter wear was identified as the root cause for stick-slip. A new-generation of abrasion resistant cutters was implemented on the reamer and the BHA was optimized to reduce the weight at the reamer. The new assembly drilled and enlarged shoe-to-shoe in one run with minimum stick-slip and vibration.
A Survey of Mučnik and Medvedev Degrees
Authors: Hinman Peter G. 
Published: April 2012

AbstractWe survey the theory of Mučnik (weak) and Medvedev (strong) degrees of subsets of ωω with particular attention to the degrees of subsets of ω2. Sections 1–6 present the major definitions and results in a uniform notation. Sections 7–16 present proofs, some more complete than others, of the major results of the subject together with much of the required background material.
On rational limits of Shelah–Spencer graphs
Authors: Brody Justin , Laskowski M. C. 
Published: April 2012

AbstractGiven a sequence {αn} in (0,1) converging to a rational, we examine the model theoretic properties of structures obtained as limits of Shelah-Spencer graphsG(). We show that in most cases the model theory is either extremely well-behaved or extremely wild, and characterize when each occurs.
Truth definitions without exponentiation and the Σ1 collection scheme
Authors: Adamowicz Zofia , Kołodziejczyk Leszek Aleksander , Paris J. 
Published: April 2012

AbstractWe prove that:
• if there is a model of IΔ0 + ¬exp with cofinal Σ1-definable elements and a Σ1 truth definition for Σ1 sentences, then IΔ0 + ¬exp + ¬BΣ1 is consistent,• there is a model of IΔ0 + Ω1 + ¬exp with cofinal Σ1-definable elements, both a Σ2 and a Π2 truth definition for Σ1 sentences, and for each n ≥ 2, a Σn truth definition for Σn sentences.The latter result is obtained by constructing a model with a recursive truth-preserving translation of Σ1 sentences into boolean combinations of sentences.We also present an old but previously unpublished proof of the consistency of IΔ0 + ¬exp + ¬BΣ1 under the assumption that the size parameter in Lessan's Δ0 universal formula is optimal. We then discuss a possible reason why proving the consistency of IΔ0 + ¬exp + ¬BΣ1 unconditionally has turned out to be so difficult.
Sharpened lower bounds for cut elimination
Authors: Buss Samuel R. 
Published: April 2012

AbstractWe present sharpened lower bounds on the size of cut free proofs for first-order logic. Prior lower bounds for eliminating cuts from a proof established superexponential lower bounds as a stack of exponentials, with the height of the stack proportional to the maximum depthdof the formulas in the original proof. Our results remove the constant of proportionality, giving an exponential stack of height equal tod−O(1). The proof method is based on more efficiently expressing the Gentzen–Solovay cut formulas as low depth formulas.
Association of High Pulse Pressure With Proteinuria in Subjects With Diabetes, Prediabetes, or Normal Glucose Tolerance in a Large Japanese General Population Sample
Authors: Yano Yuichiro , Sato Yuji , Fujimoto Shouichi , Konta Tsuneo , Iseki Kunitoshi , Moriyama Toshiki , Yamagata Kunihiro , Tsuruya Kazuhiko , Yoshida Hideaki , Asahi Koichi , Kurahashi Issei , Ohashi Yasuo , Watanabe Tsuyoshi 
Published: April 2012

OBJECTIVE
To examine whether there is a difference in the association between high pulse pressure and proteinuria, independent of other blood pressure (BP) indices, such as systolic or diastolic BP, among subjects with diabetes, prediabetes, or normal glucose tolerance.

RESEARCH DESIGN AND METHODS
Using a nationwide health checkup database of 228,778 Japanese aged ≥20 years (mean 63.2 years; 39.3% men; none had pre-existing cardiovascular disease), we examined the association between high pulse pressure, defined as the highest quintile of pulse pressure (≥63 mmHg, n = 40,511), and proteinuria (≥1+ on dipstick, n = 12,090) separately in subjects with diabetes (n = 27,913), prediabetes (n = 100,214), and normal glucose tolerance (n = 100,651).

RESULTS
The prevalence of proteinuria was different among subjects with diabetes, prediabetes, and normal glucose tolerance (11.3 vs. 5.0 vs. 3.9%, respectively; P &lt; 0.001). In subjects with diabetes, but not those with prediabetes or normal glucose tolerance, high pulse pressure was associated with proteinuria independently of significant covariates, including systolic BP (odds ratio 1.15 [95% CI 1.04–1.28]) or diastolic or mean BP (all P &lt; 0.01). In patients with diabetes, a +1 SD increase of pulse pressure (+13 mmHg) was associated with proteinuria, even after adjustment for systolic BP (1.07 [1.00–1.13]) or diastolic or mean BP (all P &lt; 0.05).

CONCLUSIONS
Among the Japanese general population, there was a significant difference in the association between high pulse pressure and proteinuria among subjects with diabetes, prediabetes, and normal glucose tolerance. Only in diabetes was high pulse pressure associated with proteinuria independent of systolic, diastolic, or mean BP levels.
Spectroscopy of thin polyaniline films deposited during chemical oxidation of aniline
Authors: Trchová Miroslava , Morávková Zuzana , Šeděnková Ivana , Stejskal Jaroslav 
Published: April 2012

AbstractAny surface immersed in the aqueous reaction mixture used for the preparation of polyaniline becomes coated with a polyaniline film of submicrometre thickness. In this way, various materials can be modified by an overlayer of conducting polymer. The present review illustrates the role of infrared, Raman, and UV-VIS spectroscopies in the studies of polyaniline film growth. Spectroscopic methods are crucial in the evaluation of the performance of polyaniline films alone or in combination with nanoparticles of noble metals. The assessment of film ageing and stability can be followed conveniently by these methods. Carbonization of polyaniline films to nitrogen-containing carbon analogues is also discussed.
Design and evaluation of moxifloxacin hydrochloride ocular inserts
Authors: Pawar Pravin , Katara Rajesh , Majumdar Dipak 
Published: April 2012

Design and evaluation of moxifloxacin hydrochloride ocular insertsThe objective of the present investigation was to prepare and evaluate ocular inserts of moxifloxacin. An ocular insert was made from an aqueous dispersion of moxifloxacin, sodium alginate, polyvinyl alcohol, and dibutyl phthalate by the film casting method. The ocular insert (5.5 mm diameter) was cross-linked by CaCl2and was coated with Eudragit S-100, RL-100, RS-100, E-100 or L-100. Thein vitrodrug drainage/permeation studies were carried out using an all-glass modified Franz diffusion cell. The drug concentration and mucoadhesion time of the ocular insert were found satisfactory. Cross-linking and coating with polymers extended the drainage from inserts. The cross-linked ocular insert coated with Eudragit RL-100 showed maximum drug permeation compared to other formulations.
The Effects of Erythropoietin on Bacterial Translocation and Inflammatory Response in an Experimental Intestinal Obstruction Model in Rats / Uticaj Eritropoetina Na Bakterijsku Translokaciju I Inflamatorni Odgovor U Eksperimentalnom Modelu Intestinalne Opstrukcije Kod Pacova
Authors: Kapan Murat , Onder Akın , Yuksel Hatice , Evliyaoglu Osman , Firat Ugur , Tekin Recep , Gul Mesut , Aliosmanoglu Ibrahim 
Published: April 2012

SummaryBackground:Intestinal obstruction results in distortion of balance of antiinflammatory cytokines and release of oxidants, and also leads to bacterial translocation, sepsis and multiple organ failure. Asymmetric dimethylarginine is related to multiple organ failure as a new prognostic marker. Erythropoietin reduces the inflammatory response by decreasing the levels of proinflammatory cytokines and cytokine-induced apoptosis. In this study, we aimed to investigate the effectiveness of erythropoietin in reducing the severity of bacterial translocation and inflammatory response after intestinal obstruction and the relation between asymmetric dimethylarginine and inflammatory markers.Methods:Forty Wistar albino rats (200-250 g) were divided into 4 groups as follows: Group 1 (Sham), only ileocaecal junction dissection; Group 2 (Erythropoietin), ileocaecal junction dissection and 3000 lU/kg erythropoietin subcutaneously; Group 3 (Intestinal Obstruction), complete ileal ligation; Group 4 (Intestinal Obstruction + Erythropoietin), complete ileal ligation and 3000 IU/kg erythropoietin subcutaneously. After 24 hours, the rats were sacrificed by taking blood from the heart for biochemical analyses. Peritoneal swab culture, liver, mesenteric lymph nodes, spleen and ileum were collected for microbiological and histopathological examinations.Results:Erythropoietin reduced the secretion of inflammatory cytokines, oxidative damage and bacterial translocation, prevented the formation of inflammatory changes in the intestine, liver, spleen and mesenteric lymph nodes,and also significantly prevented the formation of intestinal damage after intestinal obstruction (p<0.05). Conclusions: Asymmetric dimethylarginine levels did not differ between the groups. Erythropoietin may be useful to preserve from intestinal injury and related sepsis in patients with intestinal obstruction. Asymmetric dimethylarginine is not a suitable prognostic marker.
Hyperphosphatemia - The Risk Factor for Adverse Outcome in Maintenance Hemodialysis Patients
Authors: Petrović Dejan , Obrenović Radmila , Trbojević-Stanković Jasna , Majkić-Singh Nada , Stojimirović Biljana 
Published: April 2012

Hyperphosphatemia - The Risk Factor for Adverse Outcome in Maintenance Hemodialysis PatientsHyperphosphatemia is a potent stimulator of vascular and valvular calcifications in hemodialysis patients. To determine the prevalence of hyperphosphatemia and assess its effect on the outcome of hemodialysis patients, a total of 115 chronic hemodialysis patients were studied. Laboratory parameters were determined at baseline, and after 12 and 24 months of follow-up. Valvular calcification was assessed with echocardiography. Laboratory parameters were statistically analyzed with ANOVA. Survival analysis was performed with the Kaplan-Meier test and Log-Rank test. Hyperphosphatemia was present in 31.30% of the patients, high calcium-phosphate (Ca × P) product in 36.52% and valvular calcifications in 48.70%. Patients with serum phosphate >2.10 mmol/L and Ca × P product >5.65 mmol2/L2at baseline were at high risk for all-cause and cardiovascular mortality. Hyperphosphatemia is a risk factor for adverse outcome in patients on regular hemodialysis.
Association Between Telomere Shortening and Ageing During Occupational Exposure
Authors: Eshkoor Sima , Jahanshiri Fatemeh , Ismail Patimah , Rahman Sabariah , Moin Saidi , Adon Mohd 
Published: April 2012

Association Between Telomere Shortening and Ageing During Occupational ExposureTelomere length is considered as a biomarker of ageing, resulting in shortening during the process. The present investigation was an attempt to determine the relative telomere length in mechanical workshop workers. Telomere length shortening in cells during occupational exposure causes accelerated ageing. Genomic DNA was isolated from buccal epithelial cells collected from 240 individuals, comprising two groups of 120 exposed workers and 120 unexposed controls. Telomere length was measured by using real time PCR. Both telomere (T) and single copy gene (S) specific primers were used to compute the relative T/S ratio and expressed as the relative telomere length. Telomere length differed significantly between the workers and controls (p<0.05). The results showed an indirect and significant association (r=-0.356, p=0.001) between age and telomere length in the workers. This study showed that the difference in telomere length shortening was statistically significant (p<0.05) between the workers and controls. It was concluded that occupational exposure acts as a risk factor to enhance telomere length shortening and accelerate ageing.
Analysis of Codon 972 (Gly → Arg) Polymorphism in IRS-1 Gene in Type 2 Diabetic Population
Authors: Kumar Robby , Sharan Nishant 
Published: April 2012

Analysis of Codon 972 (Gly → Arg) Polymorphism in IRS-1 Gene in Type 2 Diabetic PopulationPolymorphism of Insulin Receptor Substrate-1, especially the GGG→AGG (Gly-Arg) substitution at codon 972, is one of the major factors leading to the development of type 2 diabetes mellitus. This defect in IRS-1 causes insulin resistance along with many other consequences. It generally impairs insulin signalling via the phosphadylinositol-3 (PI3)-Kinase pathway. In this study, the heterozygous Gly→Arg substitution at codon 972 of the IRS-1 gene was found in 2 of the 43 control Indian subjects, which is higher than normal when compared with the other population. The prevalence of the codon 972 GGG→AGG substitutions was found to be around 4.6%, which may be due to a predisposition factor. In diabetic subjects, on the other hand, 5 out of 43 showed substitution at codon 972, with a percent prevalence of 14%, establishing the role of the polymorphism of IRS-1 codon in the prevalence of diabetes mellitus.
Empirical investigation of two designs of incline solar water desalination system
Authors: Agboola Phillips , Egelioglu Fuat 
Published: April 2012

Empirical investigation of two designs of incline solar water desalination system
This paper presents an experimental investigation of two incline solar water desalination (ISWD) systems. One design uses spray jets for spraying water onto the absorber plate, while the other uses a longitudinal slot for getting the inlet water on the absorber plate. The first ever ISWD system constructed and tested by Aybar et al (2005) used the longitudinal slot with a maximum daily production of 2.995 kg/m2 day. The Aybar et al design produced 3.4 kg/m2-day while the new design produced 6.41 kg/m2-day for wick on absorber plate system day during the hottest months in Famagusta (July-August 2010). Also tested was the influence of porous media (wire mesh), wick on the absorber plate. The effect of number of spray jets used in the system on the daily productivity and efficiency of the systems were also investigated.
Performance of silica aerogels modified with amino functional groups in PB(II) and CD(II) removal from aqueous solutions
Authors: Faghihian Hossein , Nourmoradi Heshmatollah , Shokouhi Maryam 
Published: April 2012

Performance of silica aerogels modified with amino functional groups in PB(II) and CD(II) removal from aqueous solutions
The adsorption behavior of Pb(II) and Cd(II) ions in aqueous solutions on silica aerogels modified with amino propyl triethoxysilane was investigated as a function of pH, contact time, adsorbate concentration and adsorbent dose. It was found that maximum adsorption of Pb(II) and Cd(II) ions occurs at pH 6.0 and pH 8.0, respectively. The optimum contact time to obtain equilibrium adsorption with the modified silica aerogel was experimentally found to be around 48h. Adsorption isotherms clearly indicated that the adsorption behavior of metals ions on the modified silica aerogels is fitted well with both the Langmuir and Freundlich isotherms. The maximum adsorption capacities of Pb(II) and Cd(II) on modified silica aerogel were found to be 45.45mg/g and 35.71mg/g, respectively. The results indicated that silica aerogels modified with amino functional groups can be used as an efficient adsorbent in the removal of metal ions such as Pb(II) and Cd(II) from aqueous solutions.
Stimuli responsive polymeric nanoparticles in regulated drug delivery for cancer
Authors: Yadav Deepak , Suri Suruchi , Chaudhary Anis , Hemant  , Beg Mohd , Garg Veena , Asif Mohd , Ahmad Altaf 
Published: April 2012

Stimuli responsive polymeric nanoparticles in regulated drug delivery for cancer
Stimuli-responsive drug delivery system is a concept in which a drug is delivered at a suitable rate in response to stimuli. States of diseases may cause an alteration in some parameters of the body (e.g. in tumors) and the onset and offset of the drug delivery can be done by using this as a stimuli or a "trigger". Stimuli-responsive ("intellectual" or "sharp") resources and molecules show abrupt property changes in response to miniature changes in external stimuli such as pH, temperature etc. For regulated drug delivery, environmental stimuli such as pH and temperature, which undertake phase transition in polymer system, have been investigated. Thermally-responsive polymers can be tuned to a preferred temperature variety by copolymerization with a hydrophilic co-monomer or a hydrophobic co-monomer. Hydrophilic co-monomers increase the LCST while hydrophobic co-monomers decrease the LCST. The stimuli responsive polymer for regulated drug delivery can contain a polymer and copolymers having equilibrium of hydrophilic and hydrophobic groups. A number of these polymers have been investigated extensively and some success in drug delivery with them has been achieved, such as polymers and copolymers of N-isopropylacrylamide, PLGA, and PLA, HEMA etc. Thus this review is designed for stimuli pH and temperature responsive polymeric nanoparticles, which would be helpful to treat various cronic diseases such as cancer and others, for scientists in the field of the regulated drug delivery system.
Optimization and equilibrium studies of Pb(II) removal by Grewia Asiatica seed: a factorial design approach
Authors: Siyal Ali , Memon Saima , Khaskheli Mazhar 
Published: April 2012

Optimization and equilibrium studies of Pb(II) removal by Grewia Asiatica seed: a factorial design approach
This study aims to explore the efficiency of an agro waste material for the remediation of Pb(II) contaminated water. A factorial design approach is adopted to optimize removal efficiency and to study the interaction between effective variables. A face-centered Draper-Lin composite design predicted 100% removal efficiency at optimum variables; pH 8, initial concentration of Pb(II) ion 12mg/L, sorbent dose 200mg and agitation time 110 min. Regration coefficient (R2 = 99.9%) of a plot of the predicted versus the observed values and p value (>0.05) confirms the applicability of the predicted model. Langmuir and Dubinin-Radushkevich (D-R) isotherm models were applicable to sorption data with the Langmuir sorption capacity of 21.61±0.78 mg/g. The energy of sorption was found to be 13.62±0.32 kJ/mol expected for ion-exchange or chemisorption nature of sorption process. Characterization of Grewia seed suggested a possible contribution of carboxyl and hydroxyl groups in the process of biosorption. The present study shows that Grewia seeds can be used effectively for the remediation of Pb(II) contaminated water.
Improving flexibility and endurance of elderly women through a six-month training programme
Authors: Plachy Judit Kopkáné , Kovách Magdolna Vécseyné , Bognár József 
Published: April 2012

PurposeAdvancing age is associated with predictable sensory, motor and cognitive changes, which may have a potential impact on an older person's ability to function effectively in society. The purpose of this study was to assess whether two slightly different half-year-long regular training programmes had a positive effect on flexibility, range of motion and endurance in a sample population of elderly persons. Also analysed was which programme was found to be more effective.MethodsA group of women (<i>N</i> = 42, <i>M</i> = 67.1 ± 4.5 years) was chosen from retired persons clubs from Eger, Hungary. They were randomly divided into three groups. The first group (<i>N</i> = 15, <i>M</i> = 66.2 ± 3.8 years) took part in a one-hour-long Pilates training session three times a week, the second group (<i>N</i> = 15, <i>M</i> = 67.1 ± 5.9 years) took part in an aqua-fitness class twice a week with one Pilates class once a week and the third group (<i>N</i> = 12, <i>M</i> = 68.2 ± 3.2 years) was the control group. Pre-and postmeasurements were conducted on: flexion of the right shoulder and hip, lumbar spine flexion, thoracolumbar spine flexion, trunk lateral flexion on the right side, a 6-minute walk test, and a 30-second sit-to-stand test. Significant inter-group differences could be found in all of the measurements. Data were analysed using statistical software with the Paired-Samples T-test and Multivariate Analysis of Variance (<i>p</i> < 0.05).ResultsAfter the six-month regular training programmes no differences were found in the control group. For the two groups subjected to the training programmes all the other variables showed significant differences. The most remarkable results for the Pilates group were with the 6-minute walk and sit-to-stand test, while for the aqua-fitness and Pilates group shoulder and hip flexion.ConclusionsA half-year-long training program can considerably improve the physical performance elderly adults need in everyday life.