bluuebunny/crossref_metadata_2025 huggingface dataset:
Industry collaboration, scientific sharing, and the dissemination of knowledge
Authors: Evans James A.
Published: September 2010

Robert Merton famously characterized modern science as distinct from other social spheres by the importance of sharing. In contrast, secrecy is often claimed the most frequent method companies employ to benefit from their discoveries. This study interrogates these claims, and then uses fieldwork on academic research with the popular plant model Arabidopsis thaliana and the companies that support it to explore the nature of sharing in academy and industry. Using archival materials and panel models, the study then examines the consequences of industry collaboration, how it influences sharing between academic scientists and the reach of their ideas and materials. Interviews with academic scientists and industrial research managers reveal differences in sharing. Academics are practiced at communicating discoveries and sharing materials, but occasionally withhold to secure credit or barter to maximize it. In contrast, companies manage their ideas and resources for longer-term control. The difference is not that academic scientists never keep secrets, but that many do so badly. Statistical findings suggest that industry sponsorship influences scientists to reduce their sharing of research materials and methods, but it increases the reception of scientists’ early-stage manuscripts, probably as a substitute, enabling competing labs to infer a closed lab’s methods. Industry’s influence also affects sharing indirectly by sponsoring research in less crowded areas. In this way, industry curbs the demand as well as the supply of sharing in science. As a result, industry sponsorship limits the social, organizational, and geographic distance that sponsored ideas travel over time. Scientists find it difficult to enroll other academics in their research findings as they become enrolled in an industry project of avoiding and mitigating competing science.
Lower immunglobulin A levels but not lower cortisol or α-amylase activity in children with chronic tension-type headache
Authors: Fernández-de-las-Peñas César , Fernández-Mayoralas Daniel M , Arroyo-Morales Manuel , Ambite-Quesada Silvia , Rivas-Martínez Inés , Ortega-Santiago Ricardo , Díaz-Rodríguez Lourdes , Pareja Juan A
Published: September 2010

Objective

The tudy was designed to investigate the differences in salivary cortisol (hypothalamic-pituitary-adrenocortical[HPA] axis), immunoglobulin A (IgA) (immune system) concentrations and α-amylase (sympathetic nervous system [SNS]) activity between children with chronic tension-type headache (CTTH) and healthy children.

Methods

Thirty-six children, 10 boys and 26 girls (age: 9±2 years) with CTTH and 36 age - and sex-matched healthy children were recruited. Salivary cortisol, αm-amylase activity, salivary flow rate, IgA concentration and IgA rate were collected from non-stimulated saliva. A headache diary was used for collecting data on intensity, frequency and duration of headache for four weeks.

Results

Children with CTTH showed lower IgA concentration (p = .008) and IgA rate (p = .039), but not lower cortisol concentration (p = .447), salivary flow rate (p = .289) or α-amylase activity (p = .559), as compared to healthy children. Neither age (p < .582) nor gender (p < .227) influenced salivary markers. A significant association between the number of years with headache and IgA concentration (rs = - 0.385; p = .023) was found: the greater the number of years with headache, the lower the IgA concentration.

Conclusions

These results suggest that children with CTTH present with deficits in the immune system, but not dysfunction in the HPA axis or SNS. Future studies are needed to elucidate the direction of these relationships.
Inflammation in Neurological Disorders: A Help or a Hindrance?
Authors: Wee Yong V.
Published: September 2010

Inflammation of the central nervous system (CNS) (neuroinflammation) is now recognized to be a feature of all neurological disorders. In multiple sclerosis, there is prominent infiltration of various leukocyte subsets into the CNS. Even when there is no significant inflammatory infiltrates, such as in Parkinson or Alzheimer disease, there is intense activation of microglia with resultant elevation of many inflammatory mediators within the CNS. An extensive dataset describes neuroinflammation to have detrimental consequences, but results emerging largely over the past decade have indicated that aspects of the inflammatory response are beneficial for CNS outcomes. Benefits of neuroinflammation now include neuroprotection, the mobilization of neural precursors for repair, remyelination, and even axonal regeneration. The findings that neuroinflammation can be beneficial should not be surprising as a properly directed inflammatory response in other tissues is a natural healing process after an insult. In this article, we review the data that highlight the dual aspects of neuroinflammation in being a hindrance on the one hand but also a significant help for recovery of the CNS on the other. We consider how the inflammatory response may be beneficial or injurious, and we describe strategies to harness the beneficial aspects of neuroinflammation.
Human Cortical Control of Hand Movements: Parietofrontal Networks for Reaching, Grasping, and Pointing
Authors: Filimon Flavia
Published: September 2010

In primates, control of the limb depends on many cortical areas. Whereas specialized parietofrontal circuits have been proposed for different movements in macaques, functional neuroimaging in humans has revealed widespread, overlapping activations for hand and eye movements and for movements such as reaching and grasping. This review examines the involvement of frontal and parietal areas in hand and arm movements in humans as revealed with functional neuroimaging. The degree of functional specialization, possible homologies with macaque cortical regions, and differences between frontal and posterior parietal areas are discussed, as well as a possible organization of hand movements with respect to different spatial reference frames. The available evidence supports a cortical organization along gradients of sensory (visual to somatosensory) and effector (eye to hand) preferences.
Exploring Joint Variance Between Independent Variables and a Criterion
Authors: Schoen Jeremy L. , DeSimone Justin A. , James Lawrence R.
Published: September 2010

Current methods used in the analysis and interpretation of behavioral data tend to ignore a potentially important explanatory component. That component is the joint variance shared between predictors in explaining variance in the outcome variable. The authors provide an example of joint variance and how it could be interpreted. The authors believe ignoring this component has inhibited development of explanatory theories. The authors discuss a method developed by Mood for calculating joint explanatory variance. This method was initially developed to better interpret the unique effects of predictors on a criterion but can also be used to gain a better understanding of joint effects as well. They reanalyze published data to demonstrate the contribution of this approach in analyzing and interpreting behavioral data. They also provide a method for calculating the significance of joint variance components.
Subjective and objective fit in religious congregations: Implications for well-being
Authors: Hayward R. David , Elliott Marta
Published: September 2010

For most religiously affiliated people, the context of the religious group is a central element of the religious experience, but it is also one that has been relatively neglected in the study of the impact of religion on well-being. This study used social attraction as a framework to examine the role of individual—group fit in three congregations, with respect to four outcomes with implications for overall well-being. Structural equation modeling of survey data indicated that subjective fit with the congregation’s prototype was associated with greater life satisfaction and better self-reported health. Objective fit with observed congregational norms was associated only with greater life satisfaction. These effects were not mediated by existential certainty or by social support.
Transethmoidal Drainage of Frontal Brain Abscesses
Authors: Patron Vincent , Orsel Stéphane , Caire François , Aubry Karine , Jégoux Franck
Published: September 2010

Background: The frontal lobe is the second most common location for brain abscess after the temporal lobe. Since the advent of computed tomography and magnetic resonance imaging scanning, diagnosis has become easier, but the prognosis of brain abscess is still poor. Treatment is based on antimicrobial therapy and neurosurgical evacuation, but controversy still remains as to the merits place of each. Methods: This study describes 2 cases of patients with frontal abscesses treated by endonasal transethmoidal sinus surgery (ESS) and reviews the literature on this topic. Results: Follow-up revealed no cerebrospinal fluid leak in both patients, complete abscess drainage in one patient, and incomplete drainage in the other. Conclusions: ESS drainage of frontal abscesses is feasible in intracerebral and epidural abscesses if they have a thick shell and are in contact with the skull base. The procedure is minimally invasive and relatively simple. It allows for rapid microbial identification and an effective drainage.
The Effect of Music on Robot-Assisted Laparoscopic Surgical Performance
Authors: Siu Ka-Chun , Suh Irene H. , Mukherjee Mukul , Oleynikov Dmitry , Stergiou Nick
Published: September 2010

Music is often played in the operating room to increase the surgeon’s concentration and to mask noise. It could have a beneficial effect on surgical performance. Ten participants with limited experience with the da Vinci robotic surgical system were recruited to perform two surgical tasks: suture tying and mesh alignment when classical, jazz, hip-hop, and Jamaican music were presented. Kinematics of the instrument tips of the surgical robot and surface electromyography of the subjects were recorded. Results revealed that a significant music effect was found for both tasks with decreased time to task completion ( P = .005) and total travel distance ( P = .021) as well as reduced muscle activations ( P = .016) and increased median muscle frequency ( P = .034). Subjects improved their performance significantly when they listened to either hip-hop or Jamaican music. In conclusion, music with high rhythmicity has a beneficial effect on robotic surgical performance. Musical environment may benefit surgical training and make acquisition of surgical skills more efficient.
On the problems of mixing RCTs with qualitative research: the case of the MRC framework for the evaluation of complex healthcare interventions
Authors: Blackwood Bronagh , O'Halloran Peter , Porter Sam
Published: September 2010

In the perceived hierarchy of research designs, the results from randomised controlled trials are considered to provide the highest level of evidence. Indeed, these trials have been upheld as the gold standard in research. The benefits and limitations of the randomised controlled trial as a method of evaluating the effectiveness of healthcare interventions are presented. The paper then examines the different levels of complexity within healthcare interventions and the problems this poses in determining effectiveness. In an effort to provide a solution to this problem, the Medical Research Council produced a framework to assist investigators to develop and evaluate complex healthcare interventions. The framework is described with reference to an example of implementing and evaluating protocols for weaning patients in the intensive care unit. The framework is critiqued on the basis that it involves an ambiguous or contradictory ontology, which fails to articulate the relationship between the positivism of randomised controlled trials with the relativism of qualitative approaches. It is concluded that the use of realist strategies in combination with randomised controlled trials provides the most coherent solution to this quandary.
Developing workable research methods: lessons from a pilot study with vulnerable participants and complex assessments
Authors: Jones Susan E. , Hamilton Sharon , Perry Lin , O'Malley Claire , Halton Carol
Published: September 2010

Following acute stroke, deterioration in nutritional status and weight loss is common; few studies have investigated this, perhaps due to difficulties with recruitment and completion of complex assessments with stroke patients. This study reports the feasibility of a study protocol to determine predictors of nutritional intake in stroke patients. The aim of the study was to test the feasibility of a protocol to measure taste and smell function, and explore links with dietary intake following stroke. Patients were recruited from one Acute Stroke Unit in 2007/8. Data were collected at three time-points and entailed standardised validated assessments of taste and smell function, diet, appetite and mood state. Recruitment of this vulnerable population to a demanding assessment schedule was challenging. Of a cohort of 166 admissions, six were recruited and complete data collected from four participants. Slow recruitment was largely due to exacting inclusion criteria and rapid hospital discharge. Those who completed all assessments reported the schedule as tolerable and acceptable. This study illustrated the difficulties of recruiting this vulnerable population. Identification of reasons for slow recruitment facilitated development of measures to address them. It was possible to format a complex and lengthy assessment schedule to be acceptable to vulnerable participants.
Anterior transposition of the ulnar nerve with endoscopic assistance
Authors: Konishiike T. , Nishida K. , Ozawa M. , Ozaki T.
Published: September 2010

We treated 20 patients with cubital tunnel syndrome by anterior transposition of the ulnar nerve with endoscopic assistance. Five elbows were classified preoperatively as McGowan’s stage 1, 11 as stage 2 and four as stage 3. Excellent outcomes were obtained in nine and good in eight patients. Three patients had fair results. Improvement of symptoms occurred in all patients. There were no serious complications. All ulnar nerves remained anteriorly transposed.
Value of Ultrasonography for Detecting Ligament Damage in Athletes With Chronic Ankle Instability Compared to Computed Arthrotomography
Authors: Guillodo Yannick , Varache Sophie , Saraux Alain
Published: September 2010

Ankle sprains may be followed by chronic pain and/or instability, which may induce substantial disability, most notably in athletes. Chronic ankle instability promotes the development of cartilage lesions in athletes. Therefore, accurate evaluation of the ankle ligaments is crucial to the optimal management of chronic ankle instability after a sprain. The objective of this study was to assess the performance of ultrasonography in assessing damage to the anterior talofibular ligament (ATFL) in athletes with chronic ankle instability after a sprain. Consecutive patients seen at the author’s clinic for ankle instability more than 3 months after a sprain underwent ultrasonography and computed arthrotomography after a clinical anterior drawer stress test. Cohen’s kappa was computed to evaluate agreement between the 2 imaging modalities. This study included 56 patients, 46 men and 10 women, aged 15 to 69 years (mean, 30.1 ± 10.6 years). Mean time from the sprain to imaging was 7.6 ± 4.02 months. ATFL damage was found by ultrasonography in 34 (61%) of 56 patients and by computed arthrotomography in 39 of 55 patients (71%; k = 0.76). Cartilage damage was visualized by computed arthrotomography in 14 (25%) patients, all of whom had ATFL damage. Agreement was substantial (k = 0.76) between ultrasonography and computed arthrotomography for assessing the ATFL. The data support the use of ultra-sonography as the second-line investigation after a standard radiographic assessment in athletes with chronic ankle instability after a sprain.
Antithrombin-heparin covalent complex reduces microemboli during cardiopulmonary bypass in a pig model
Authors: Klement Petr , Berry Leslie R. , Liao Peng , Wood Henry , Tressel Paul , Smith Lesley J. , Haque Nihal , Weitz Jeffery I. , Hirsh Jack , Paredes Nethnapha , Chan Anthony K.C.
Published: September 2010

Transcranial Doppler-detected high-intensity transient signals (HITS) during cardiopulmonary bypass (CPB) surgery have been associated with postoperative neurocognitive dysfunction, suggesting microemboli in the brain could be a contributing factor. HITS occur despite administration of unfractionated heparin (UFH). This study was done to determine whether antithrombin-heparin covalent complex (ATH), a more potent anticoagulant than heparin, can reduce HITS during CPB. In a pig CPB model, ATH, UFH, or UFH + antithrombin (AT) was intravenously administered to female Yorkshire pigs after sternotomy. Twenty minutes later, hypothermic CPB was initiated and continued for 1.25 hours, then normothermia was re-established for 45 minutes. Protamine sulfate was given to neutralize the anticoagulants, and pigs were allowed to recover. HITS were monitored using an arterial flow probe placed over the carotid artery. Compared with UFH (300 or 1000 U/kg), ATH reduced the number of HITS during CPB in a dose-dependent manner. AT (3 mg/kg) + UFH (300 U/kg) resulted in an intermediate HITS rate between UFH and ATH (2 mg/kg in terms of AT). Examination of brain sections for emboli formation confirmed that, similar to HITS, number of thrombi decreased in direct proportion to ATH dosage. These results support the hypotheses that the majority of HITS represent thromboemboli and that ATH reduces emboli formation during CPB.
Respiratory health in children, and indoor exposure to (1,3)-β-d-glucan, EPS mould components and endotoxin
Authors: Tischer C. , Gehring U. , Chen C-M. , Kerkhof M. , Koppelman G. , Sausenthaler S. , Herbarth O. , Schaaf B. , Lehmann I. , Krämer U. , Berdel D. , von Berg A. , Bauer C.P. , Koletzko S. , Wichmann H-E. , Brunekreef B. , Heinrich J.
Published: September 2010

For a long time, exposure to mould and dampness-derived microbial components was considered a risk factor for the development of respiratory diseases and symptoms. Some recent studies suggested that early childhood exposure to mould components, such as (1,3)-β-d-glucan and extracellular polysaccharides (EPSs), may protect children from developing allergy. We investigated the association of exposure to (1,3)-β-d-glucan, EPS and endotoxin with asthma and allergies in 6-yr-old children.

This investigation was the follow-up to a nested case–control study among three European birth cohorts. Children from two ongoing birth cohort studies performed in Germany (n = 358) and one in the Netherlands (n = 338) were selected. Levels of (1,3)-β-d-glucan, EPS and endotoxin were measured in settled house dust sampled from children’s mattresses and living-room floors when the children were, on average, 5 yrs of age. At the age of 6 yrs, health outcome information was available for 678 children.

In the two German subsets, domestic EPS and endotoxin exposure from children’s mattresses were significantly negatively associated with physician-diagnosed asthma (OR per interquartile range increase 0.60 (95% CI 0.39–0.92) and 0.55 (95% CI 0.31–0.97), respectively). In addition, EPS exposure was inversely related to physician-diagnosed allergic rhinitis (OR 0.50, 95% CI 0.31–0.81). For the Dutch population, no associations were observed between exposure to microbial agents and respiratory health outcomes.

We found inverse associations between domestic exposure to EPS and endotoxin from children’s mattresses, and doctor-diagnosed asthma and rhinitis in German, but not in Dutch, school children. The reasons for the differences between countries are not clear.
Sequential algorithm for life threatening cardiac pathologies detection based on mean signal strength and EMD functions
Authors: Anas Emran M Abu , Lee Soo Y , Hasan Md K
Published: September 2010

Background

Ventricular tachycardia (VT) and ventricular fibrillation (VF) are the most serious cardiac arrhythmias that require quick and accurate detection to save lives. Automated external defibrillators (AEDs) have been developed to recognize these severe cardiac arrhythmias using complex algorithms inside it and determine if an electric shock should in fact be delivered to reset the cardiac rhythm and restore spontaneous circulation. Improving AED safety and efficacy by devising new algorithms which can more accurately distinguish shockable from non-shockable rhythms is a requirement of the present-day because of their uses in public places.

Method

In this paper, we propose a sequential detection algorithm to separate these severe cardiac pathologies from other arrhythmias based on the mean absolute value of the signal, certain low-order intrinsic mode functions (IMFs) of the Empirical Mode Decomposition (EMD) analysis of the signal and a heart rate determination technique. First, we propose a direct waveform quantification based approach to separate VT plus VF from other arrhythmias. The quantification of the electrocardiographic waveforms is made by calculating the mean absolute value of the signal, called the mean signal strength. Then we use the IMFs, which have higher degree of similarity with the VF in comparison to VT, to separate VF from VTVF signals. At the last stage, a simple rate determination technique is used to calculate the heart rate of VT signals and the amplitude of the VF signals is measured to separate the coarse VF from VF. After these three stages of sequential detection procedure, we recognize the two components of shockable rhythms separately.

Results

The efficacy of the proposed algorithm has been verified and compared with other existing algorithms, e.g., HILB [1], PSR [2], SPEC [3], TCI [4], Count [5], using the MIT-BIH Arrhythmia Database, Creighton University Ventricular Tachyarrhythmia Database and MIT-BIH Malignant Ventricular Arrhythmia Database. Four quality parameters (e.g., sensitivity, specificity, positive predictivity, and accuracy) were calculated to ascertain the quality of the proposed and other comparing algorithms. Comparative results have been presented on the identification of VTVF, VF and shockable rhythms (VF + VT above 180 bpm).

Conclusions

The results show significantly improved performance of the proposed EMD-based novel method as compared to other reported techniques in detecting the life threatening cardiac arrhythmias from a set of large databases.
Scoring Rules and Decision Analysis Education
Authors: Bickel J. Eric
Published: September 2010

Experiential learning is perhaps the most effective way to teach. One example is the scoring procedure used for exams in some decision analysis programs. Under this grading scheme, students take a multiple-choice exam, but rather than simply marking which answer they think is correct, they must assign a probability to each possible answer. The exam is then scored with a special scoring rule, under which students' best strategy is to avoid guessing and instead assign their true beliefs. Such a scoring function is known as a strictly proper scoring rule. In this paper, we discuss several different scoring rules and demonstrate how their use in testing situations provides insights for both students and instructors.
Eliciting Patients' Revealed Preferences: An Inverse Markov Decision Process Approach
Authors: Erkin Zeynep , Bailey Matthew D. , Maillart Lisa M. , Schaefer Andrew J. , Roberts Mark S.
Published: September 2010

Estimating patient preferences over various health states is an important problem in health care decision modeling. Direct approaches, which involve asking patients various abstract questions, have significant drawbacks. We propose a new approach that infers patient preferences based on observed decisions via inverse optimization techniques. We illustrate our methods on the timing of a living-donor liver transplant.
Target Age and the Acquisition of Innovation in High-Technology Industries
Authors: Ransbotham Sam , Mitra Sabyasachi
Published: September 2010

External acquisition of new technology is a growing trend in the innovation and product development process, particularly in high-technology industries, as firms complement internal research and development efforts with aggressive acquisition programs. Yet, despite its importance, there has been little empirical research on the timing of acquisition decisions in high-technology environments. Should organizations wait until more information is available about the target and its markets so that a better valuation can be obtained? Or should the target be acquired early to lower acquisition cost and gain early access to key technologies? Applying an event study methodology to technology acquisitions in the telecommunications industry from 1995 to 2001, we find evidence that supports acquiring early in the face of uncertainty. Our analytical model and empirical analysis uncover two characteristics of young targets that drive benefits from early acquisitions—flexible growth options that provide greater opportunities for synergistic fit, and greater valuation uncertainty that leads to lower prices. However, the negative effect of target age on acquirer value is partially mitigated if the target has recent patents or is privately held. In addition, the probability of acquisition is higher for targets that have signals of higher quality, and lower for targets that have superior access to capital and resources.
Patients with primary hyperparathyroidism have lower circulating sclerostin levels than euparathyroid controls
Authors: van Lierop A H , Witteveen J E , Hamdy N A T , Papapoulos S E
Published: September 2010

Objective

In vitroandin vivostudies in animal models have shown that parathyroid hormone (PTH) inhibits the expression of theSOSTgene, which encodes sclerostin, an osteocyte-derived negative regulator of bone formation. We tested the hypothesis that chronic PTH excess decreases circulating sclerostin in humans.

Design

We studied 25 patients with elevated serum PTH concentrations due to primary hyperparathyroidism (PHPT) and 49 patients cured from PHPT after successful parathyroidectomy (PTx; euparathyroid controls (EuPTH)).

Methods

We measured plasma PTH and serum sclerostin levels and the serum markers of bone turnover alkaline phosphatase, P1NP, and β-CTX.

Results

As expected by the design of the study, mean plasma PTH was significantly higher (P<0.001) in PHPT patients (15.3 pmol/l; 95% confidence interval (CI): 11.1–19.5) compared with that of EuPTH controls (4.1 pmol/l; 95% CI: 3.6–4.5). PHPT patients had significantly lower serum sclerostin values compared with those in EuPTH subjects (30.5 pg/ml; 95% CI: 26.0–35.1 vs 45.4 pg/ml; 95% CI: 40.5–50.2;P<0.001) and healthy controls (40.0 pg/ml; 95% CI: 37.1–42.9;P=0.01). Plasma PTH concentrations were negatively correlated with serum sclerostin values (r=−0.44;P<0.001). Bone turnover markers were significantly correlated with PTH, but not with sclerostin.

Conclusion

Patients with PHPT have significantly lower serum sclerostin values compared with PTx controls with normal PTH concentrations. The negative correlation between PTH and sclerostin suggests thatSOSTis downregulated by PTH in humans.
Group I p21-activated kinases regulate thyroid cancer cell migration and are overexpressed and activated in thyroid cancer invasion
Authors: McCarty Samantha K , Saji Motoyasu , Zhang Xiaoli , Jarjoura David , Fusco Alfredo , Vasko Vasyl V , Ringel Matthew D
Published: September 2010

p21-activated kinases (PAKs) are a family of serine/threonine kinases that regulate cytoskeletal dynamics and cell motility. PAKs are subdivided into group I (PAKs 1–3) and group II (PAKs 4–6) on the basis of structural and functional characteristics. Based on prior gene expression data that predicted enhanced PAK signaling in the invasive fronts of aggressive papillary thyroid cancers (PTCs), we hypothesized that PAKs functionally regulate thyroid cancer cell motility and are activated in PTC invasive fronts. We examined PAK isoform expression in six human thyroid cancer cell lines (BCPAP, KTC1, TPC1, FTC133, C643, and SW1746) by quantitative reverse transcription-PCR and western blot. All cell lines expressed PAKs 1–4 and PAK6 mRNA and PAKs 1–4 protein; PAK6 protein was variably expressed. Samples from normal and malignant thyroid tissues also expressed PAKs 1–4 and PAK6 mRNA; transfection with the group I (PAKs 1–3) PAK-specific p21 inhibitory domain molecular inhibitor reduced transwell filter migration by ∼50% without altering viability in all cell lines (P<0.05). BCPAP and FTC133 cells were transfected with PAK1, PAK2, or PAK3-specific small interfering RNA (siRNA); only PAK1 siRNA reduced migration significantly for both cell lines. Immunohistochemical analysis of seven invasive PTCs demonstrated an increase in PAK1 and pPAK immunoactivity in the invasive fronts versus the tumor center. In conclusion, PAK isoforms are expressed in human thyroid tissues and cell lines. PAK1 regulates thyroid cancer cell motility, and PAK1 and pPAK levels are increased in PTC invasive fronts. These data implicate PAKs as regulators of thyroid cancer invasion.
Interfacial transfer of Cd2+ assisted by 4′ — morpholino-acetophenone-4-phenyl-3-thiosemicarbazone across the water/1,2-dichloroethane interface
Authors: Bingol Haluk , Atalay Tevfik
Published: September 2010

The assisted transfer of heavy metal ions by interfacial complexation with 4′-morpholinoacetophenone-4-phenyl-3-thiosemicarbazone (MAPPT) at the interface between two immiscible electrolyte solutions (ITIES) was studied by cyclic voltammetry. The voltammograms obtained across the water/1,2-dichloroethane interface using the MAPPT ligand in the organic phase shows that the assisted metal ion transfers have different nature for different ions. The quasi-reversible voltammetric peak of the Cd2+ ion was obtained and is discussed in detail. The dependence of the half-wave transfer potential on MAPPT concentration showed that the equilibrium is effectively displaced towards a 1:3 (metal:ligand) stoichiometry with an association constant of log β o =15.46 (±0.11) for the Cd2+ ion, corresponding to the TIC/TID mechanism.
Efficiency of acoustic heating produced in the thermoviscous flow of a fluid with relaxation
Authors: Perelomova Anna , Pelc-Garska Weronika
Published: September 2010

Instantaneous acoustic heating of a fluid with thermodynamic relaxation is the subject of investigation. Among others, viscoelastic biological media described by the Maxwell model of the viscous stress tensor, belong to this type of fluid. The governing equation of acoustic heating is derived by means of the special linear combination of conservation equations in differential form, allowing the reduction of all acoustic terms in the linear part of the final equation, but preserving terms belonging to the thermal mode responsible for heating. The procedure of decomposition is valid for weakly nonlinear flows, resulting in the nonlinear terms responsible for the modes interaction. Nonlinear acoustic terms form a source of acoustic heating in the case of dominative sound, which reflects the thermoviscous and dispersive properties of a fluid. The method of deriving the governing equations does not need averaging over the sound period, and the final governing dynamic equation of the thermal mode is instantaneous. Some examples of acoustic heating are illustrated and discussed, conclusions about efficiency of heating caused by different sound impulses are made.
Changes in 8–12 μm CdxHg1−xTe photodiode arrays caused by fast neutron irradiation
Authors: Lysiuk I.O. , Gumenjuk-Sichevska J.V. , Dvoretsky S.A. , Varavin V.S.
Published: September 2010

We have measured the current-voltage characteristics of the long-wavelength infrared (LWIR) photodiode array, formed on the epitaxial CdxHg1−xTe film (x = 0.21–0.23) with a high concentration of the Shockley-Read-Hall centres, before and after irradiating it with fast neutrons (energy 1 MeV, dose 5×1013 cm−2) at room temperature. Residual changes in current-voltage characteristics, persisting after 20 days, have been identified. Model calculations indicate that the Shockley-Read-Hall centre concentration increases 2–4 times, and the carrier lifetime decreases 2–5 times after the irradiation.
Uncooled MWIR and LWIR photodetectors in Poland
Authors: Piotrowski J. , Pawluczyk J. , Piotrowski A. , Gawron W. , Romanis M. , Kłos K.
Published: September 2010

The history, status, and recent progress in the middle and long wavelength Hg1−xCdxTe infrared detectors operating at near room temperatures are reviewed. Thermal generation of charge carriers in narrow gap semiconductor is a major limitation or sensitivity. Cooling is a straightforward way to suppress thermal generation of charge carriers and reduce related noise. However, at the same time, cooling requirements make infrared systems bulky, heavy, and inconvenient in use. A number of concepts to improve performance of photodetectors operating at near room temperatures have been proposed and implemented. Recent considerations of the fundamental detector mechanisms suggest that near perfect detection can be achieved without the need for cryogenic cooling. This paper, to a large degree, is based on the research, development, and commercialization of uncooled HgCdTe detectors in Poland. The devices have been based on 3D-variable band gap and doping level structures that integrate optical, detection and electric functions in a monolithic chip. The device architecture is optimized for the best compromise between requirements of high quantum efficiency, efficient and fast collection of photogenerated charge carriers, minimized thermal generation, reduced parasitic impedances, wide linear range, wide acceptance angles and other device features. Recent refinements in the devices design and technology have lead to sensitivities close to the background radiation noise limit, extension of useful spectral range to > 16 μm wavelength and picosecond range response times. The devices have found numerous applications in various optoelectronic systems. Among them there are fast scan FTIR spectrometers developed under MEMFIS project.
History of HgTe-based photodetectors in Poland
Authors: Rogalski A.
Published: September 2010

In Poland, the HgCdTe studies began in 1960 at the Institute of Physics, Warsaw University. The material processing laboratory was created by Giriat and later by Dziuba, Gałązka, and others. Bridgman technique with sealed thick wall quartz ampoules was used to grow material suitable for research and experimental devices. Among the first papers published in 1961 and 1963 there were the Polish works devoted to preparation, doping, and electrical properties of HgCdTe.

Infrared detector’s research and development efforts in Poland were concentrated mostly on uncooled market niche. At the beginning, a modified isothermal vapour phase epitaxy has been used for research and commercial fabrication of photoconductive, photoelectromagnetic and other HgCdTe devices. Bulk growth and liquid phase epitaxy were also used. Recently, the fabrication of infrared devices relies on low temperature epitaxial technique, namely metalorganic vapour phase deposition.

At present stage of development, the photoconductive and photoelectromagnetic (PEM) detectors are gradually replaced with photovoltaic devices which offer inherent advantages of no electric or magnetic bias, no heat load and no flicker noise. Potentially, photodiodes offer high performance and very fast response. However, conventional photovoltaic uncooled detectors suffer from low quantum efficiency and very low junction resistance. The problems have been solved with advanced band gap engineered architecture, multiple cell heterojunction devices connected in series, and monolithic integration of the detectors with microoptics.

In final part of the paper, the Polish achievements in technology and performance of HgMnTe and HgZnTe photodetectors are presented.
Mid infrared resonant cavity detectors and lasers with epitaxial lead-chalcogenides
Authors: Zogg H. , Rahim M. , Khiar A. , Fill M. , Felder F. , Quack N.
Published: September 2010

Wavelength tunable emitters and detectors in the mid-IR wavelength region allow applications including thermal imaging and gas spectroscopy. One way to realize such tunable devices is by using a resonant cavity. By mechanically changing the cavity length with MEMS mirror techniques, the wavelengths may be tuned over a considerable range.

Resonant cavity enhanced detectors (RCED) are sensitive at the cavity resonance only. They may be applied for low resolution spectroscopy, and, when arrays of such detectors are realized, as multicolour IR-FPA or “IR-AFPA”, adaptive focal plane arrays.

We report the first room temperature mid-IR VECSEL (vertical external cavity surface emitting laser) with a wavelength above 3 μm. The active region is just 850 nm PbSe, followed by a 2.5 pair Bragg mirror. Output power is > 10 mW at RT.
Influence of near-surface graded-gap layers on electrical characteristics of MIS-structures based on MBE grown HgCdTe
Authors: Voitsekhovskii A.V. , Nesmelov S.N. , Dzyadukh S.M. , Varavin V.S. , Dvoretskii S.A. , Mikhailov N.N. , Sidorov Yu.G. , Yakushev M.V.
Published: September 2010

The paper examines influence of near-surface graded-gap layers on electrical characteristics of MIS-structures fabricated on heteroepitaxial Hg1−xCdxTe films grown by molecular beam epitaxy (MBE). Two types of insulators, i.e., two-layer SiO2/Si3N4 and anodic oxide films were used. As it is seen from the depth and width of the valley on the C-V characteristics, the capacitance is found to vary in a wide range, in contrast to the structures without graded-gap layers. It is shown that the graded-gap layer under MIS-structures with x = 0.22 effectively reduces the tunnelling generation via deep levels and increases a lifetime of minority carriers in the space charge region and its differential resistance. The properties of the HgCdTe-insulator interfaces are studied.
Energy-band diagrams and capacity-voltage characteristics of CdxHg1−xTe-based variband structures calculated with taking into account dependence of electron affinity on a composition
Authors: Voitsekhovskii A.V. , Gorn D.I. , Nesmelov S.N. , Kokhanenko A.P.
Published: September 2010

The purpose of this scientific work is the research of energy-band diagrams and capacity-voltage characteristics of CdxHg1−xTe-based variband heteroepitaxial structures with taking into account the dependence of electron affinity on the composition.

Numerical simulations of energy-band diagrams and capacity-voltage characteristics for metal-insulator-semiconductor structures based on CdxHg1−xTe-variable composition layers are carried out in this work. Energy diagrams are calculated with taking into account the dependence of electron affinity on the composition x of CdxHg1−xTe. This dependence was obtained in terms of dependence of the local electroneutrality level on the composition for CdxHg1−xTe.
A novel approach to increase emission wavelength of InAs/GaAs quantum dots by using a quaternary capping layer
Authors: Chowdhury S. , Adhikary S. , Halder N. , Chakrabarti S.
Published: September 2010

In this paper, we present a new approach to obtain large size dots in an MBE grown InAs/GaAs multilayer quantum dot system. This is achieved by adding an InAlGaAs quaternary capping layer in addition to a high growth temperature (590°C) GaAs capping layer with the view to tune the emission wavelength of these QDs towards the 1.3 μm/0.95 eV region important for communication devices. Strain driven migration of In atoms from InAlGaAs alloy to the InAs QDs effectively increases the size of QDs. Microscopic investigations were carried out to study the dot size and morphology in the different layers of the grown samples. Methods to reduce structural defects like threading dislocations in multilayer quantum dot samples are also studied.
Stimulated and spontaneous far infra-red emission from uniaxially strained gapless Hg1−xCdxTe
Authors: Gasan-Zade S.G. , Strikha M.V. , Shepelskii G.A.
Published: September 2010

The intensive far infra-red irradiation in the range of 80–100 μm was observed in uniaxially strained gapless p-Hg1−xCdxTe (MCT) with x = 0.14 in the strong electric field. The inverse occupation in strained MCT is created because the hot electrons distribution occurs in the c-band under impact ionization, while the holes are localized near the v-band top. The probability of band-to-band radiative transition increases dramatically when the acceptor level becomes resonance in the v-band. At threshold values of strain and electric field (P = 2.5–2.7 kbar, E = 50–55 V/cm), increase in irradiation (by 3 orders of magnitude) and increase in current (by 4–6 times) occur.
Comparison of single-layer and bilayer InAs/GaAs quantum dots with a higher InAs coverage
Authors: Sengupta S. , Shah S.Y. , Halder N. , Chakrabarti S.
Published: September 2010

Epitaxially grown self-assembled InAs quantum dots (QDs) have found applications in optoelectronics. Efforts are being made to obtain efficient quantum-dot lasers operating at longer telecommunication wavelengths, specifically 1.3 μm and 1.55 μm. This requires narrow emission linewidth from the quantum dots at these wavelengths. In InAs/GaAs single layer quantum dot (SQD) structure, higher InAs monolayer coverage for the QDs gives rise to larger dots emitting at longer wavelengths but results in inhomogeneous dot-size distribution. The bilayer quantum dot (BQD) can be used as an alternative to SQDs, which can emit at longer wavelengths (1.229 μm at 8 K) with significantly narrow linewidth (∼16.7 meV). Here, we compare the properties of single layer and bilayer quantum dots grown with higher InAs monolayer coverage. In the BQD structure, only the top QD layer is covered with increased (3.2 ML) InAs monolayer coverage. The emission line width of our BQD sample is found to be insensitive towards post growth treatments.
Human Decidual Tissue Contains Differentiated CD8+ Effector-Memory T Cells with Unique Properties
Authors: Tilburgs Tamara , Schonkeren Dorrith , Eikmans Michael , Nagtzaam Nicole M. , Datema Gert , Swings Godelieve M. , Prins Frans , van Lith Jan M. , van der Mast Barbara J. , Roelen Dave L. , Scherjon Sicco A. , Claas Frans H.
Published: September 2010

During pregnancy, maternal lymphocytes at the fetal–maternal interface play a key role in the immune acceptance of the allogeneic fetus. Recently, CD4+CD25bright regulatory T cells have been shown to be concentrated in decidual tissue, where they are able to suppress fetus-specific and nonspecific immune responses. Decidual CD8+ T cells are the main candidates to recognize and respond to fetal HLA-C at the fetal–maternal interface, but data on the characteristics of these cells are limited. In this study we examined the decidual and peripheral CD8+ T cell pool for CD45RA, CCR7, CD28, and CD27 expression, using nine-color flow cytometry. Our data demonstrate that decidual CD8+ T cells mainly consist of differentiated CD45RA−CCR7− effector-memory (EM) cells, whereas unprimed CD45RA+CCR7+ naive cells are almost absent. Compared with peripheral blood EM CD8+ T cells, the decidual EM CD8+ T cells display a significantly reduced expression of perforin and granzyme B, which was confirmed by immunohistochemistry of decidual tissue sections. Interestingly, quantitative PCR analysis demonstrates an increased perforin and granzyme B mRNA content in decidual EM CD8+ T cells in comparison with peripheral blood EM CD8+ T cells. The presence of high levels of perforin and granzyme B mRNA in decidual EM T cells suggests that decidual CD8+ T cells pursue alternative means of EM cell differentiation that may include a blockade of perforin and granzyme B mRNA translation into functional perforin and granzyme B proteins. Regulation of decidual CD8+ T cell differentiation may play a crucial role in maternal immune tolerance to the allogeneic fetus.
IL-1β–Mediated Signals Preferentially Drive Conversion of Regulatory T Cells but Not Conventional T Cells into IL-17–Producing Cells
Authors: Li Lequn , Kim Jin , Boussiotis Vassiliki A.
Published: September 2010

Regulatory T cells (Tregs) are committed to suppressive functions. Recently, it was proposed that Tregs could produce IL-17 under proinflammatory, polarizing conditions. We studied the role of Tregs on IL-17 production in the absence of exogenous cytokines and insults. Using in vitro and in vivo approaches, we determined that under neutral conditions, simultaneous activation of Tregs and naive CD4+ conventional T cells in the presence of APCs resulted in conversion of Tregs into IL-17–producing cells, and endogenous IL-1β was mandatory in this process. Mechanistic analysis revealed that the IL-1R1 was highly expressed on Tregs and that IL-1β induced marked activation of p38 and JNK, which were involved in IL-17 production. These observations could have important implications on therapeutic strategies using Tregs.
Free Ig Light Chains Interact with Sphingomyelin and Are Found on the Surface of Myeloma Plasma Cells in an Aggregated Form
Authors: Hutchinson Andrew T. , Ramsland Paul A. , Jones Darren R. , Agostino Mark , Lund Maria E. , Jennings Cameron V. , Bockhorni Vanessa , Yuriev Elizabeth , Edmundson Allen B. , Raison Robert L.
Published: September 2010

Free κ L chains (FκLCs) are expressed on the surface of myeloma cells and are being assessed as a therapeutic target for the treatment of multiple myeloma. Despite its clinical potential, the mechanism by which FκLCs interact with membranes remains unresolved. In this study, we show that FκLCs associate with sphingomyelin on the plasma membrane of myeloma cells. Moreover, membrane-bound FκLCs are aggregated, suggesting that aggregation is required for intercalation with membranes. Finally, we propose a model where the binding of FκLCs with sphingomyelin on secretory vesicle membranes is stabilized by self-aggregation, with aggregated FκLCs exposed on the plasma membrane after exocytosis. Although it is well known that protein aggregates bind membranes, this is only the second example of an aggregate being found on the surface of cells that also secrete the protein in its native form. We postulate that many other aggregation-prone proteins may associate with cell membranes by similar mechanisms.
Beckwith–Wiedemann syndrome
Authors: Choufani Sanaa , Shuman Cheryl , Weksberg Rosanna
Published: September 2010

Beckwith–Wiedemann syndrome (BWS) is an imprinting disorder characterized by overgrowth, tumor predisposition, and congenital malformations. Approximately 85% of reported BWS cases are sporadic, while the remaining 15% are familial. BWS is caused by epigenetic or genomic alterations which disrupt genes in one or both of the two imprinted domains on chromosome 11p15.5. In each domain, an imprinting center regulates the expression of imprinted genes in cis. Normally in domain 1, insulin‐like growth factor 2 (IGF2) and the untranslated mRNA H19 are monoallelically expressed. In BWS, increased expression of IGF2 occurs via several mechanisms. In domain 2, CDKN1C, a growth repressor, and an untranslated RNA, KCNQ1OT1, are normally expressed monoallelically. In cases of BWS, several mechanisms result in reduced expression of CDKN1C. Recent reports of BWS cases have identified mutations outside the chromosome 11p15.5 critical region, thereby broadening the challenges in the diagnosis and genetic counseling of individuals and families with BWS. © 2010 Wiley‐Liss, Inc.
ChemInform Abstract: Effect of Chlorine Atmosphere on the Anatase‐Rutile Transformation.
Authors: GAMBOA J. A. , PASQUEVICH D. M.
Published: September 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.