bluuebunny/crossref_metadata_2025 huggingface dataset:
Konflikthåndtering og mentalisering
Authors: Frederiksen Jesper , Petersen Karin Anna , Høyer Nadine Benike Bernsten , Vase Gitte Nørreskov
Published: March 2024

At være patient indebærer lidelse og et følelsesmæssigt pres, som kan skabe utryghed.
At skulle have hjælp fra andre, under sådanne vilkår kan være udfordrende. Både for patienten og
for sygeplejersken. Her er der risiko for, at misforståelser opstår, og at en konflikt
optrappes.
Konsekvensen heraf kan være, at sygeplejen påvirkes negativt, og at det medfører dårligere
behandling for patienten og dårligt arbejdsmiljø for sygeplejersken med øget risiko for mentale
belastninger, under- og overinvolvering og forråelse. Det kan derfor være betydningsfuldt at se
nærmere på disse konfliktoptrappende situationer, og på hvordan sygeplejersken kan hjælpe
patienten, sig selv og sit arbejdsmiljø. I denne artikel vil vi belyse dette ud fra teori om
konflikthåndtering og mentalisering via Kierkegaards tanker om hjælpekunst. Teorien om
mentalisering er bl.a. kendt indenfor det psykiatriske speciale.
I mentaliseringsteorien beskrives, hvorledes fagpersoner kan forstå, opretholde og stimulere
mentaliserende processer, for at hjælpe den anden i relationen.
Motivationen forud for denne artikel er, at den somatiske sygeplejerske også bør kende til
mentalisering, non-mentalisering og mentaliserende processer, for at kunne hjælpe patienten ved
“at finde ham der, hvor han er, og begynde der”, således at misforståelser og konflikter
håndteres, og god sygepleje består.
Hvad skal der til for at brugere og forskere kan samarbejde om sundhedsforskning?
Authors: Larsen Bjarne Ledet , Karlsson Anne Wettergren
Published: March 2024

Hvordan er det muligt at udføre forskning i samarbejde med patienter og pårørende?
Spørgsmålet bliver stillet af sygeplejerske Anne Wettergren Karlsson i hendes ph.d.-studie på
Syddansk
Universitet, og det er på den baggrund, at vi har mødtes til flere samtaler om, hvad der er
vigtigt, når
forskere og brugere skal samarbejde.
Ariklen har 2 forfattere: Bjarne som er bruger af sundhedsvæsenet gennem 18 år og Anne som er
forsker.
Smart sensor interface model using IoT for pipeline integrity Cathodic Protection
Authors: Algarni Mohammed , Zwawi Mohammed
Published: April 2024

This study proposes a design of a smart sensor interface for monitoring Cathodic Protection (CP) in an Internet of Things (IoT) environment. The corrosion sensor is used to monitor voltage potential from a sacrificial anode to an underground pipe or pipelines. The past design of monitoring CP was via wired networking (for data transfer) or by onsite inspection. Although such inspection offers a very reliable monitoring method, it is expensive and inconvenient. This research proposes a new, advanced and straightforward method to monitor CP, for field engineers, by the advancement of IoT intelligence to provide suggestions and make online-orders for consumable parts. This research proposes a solution by the novel design of monitoring corrosion via CP using a smart sensor interface model in an IoT environment and smart-phone applications. The results of this system design show good monitoring performance and excellent analytical potential.
Corbinites (Subfamily Lithacoceratinae), a new genus for the giant western Canadian Late Kimmeridgian or Tithonian (Late Jurassic) ammonite Titanites occidentalis Frebold
Authors: Poulton Terence
Published: April 2024

The finding of two new specimens and a reappraisal of the single original specimen of the problematic giant Canadian Late Jurassic ammonite Titanites occidentalis Frebold results in the creation of Corbinites, n. gen. It is assigned to the ataxioceratid subfamily Lithacoceratinae largely because of the presence of variocostate and previously unrecognized ataxioceratoid ribbing in middle and late growth stages. With enigmatic ancestry and geographically removed other forms with similar characteristics, the species may have been endemic in the relatively isolated early Alberta foreland basin of western interior Canada.
On the Coincidence Theorem
Authors: Bakić Radoš
Published: March 2024

We are proving Coincidence theorem due to Walsh for the case when the total degree of a polynomial is less than the number of arguments. Also, the following result has been proven: if $$p(z)$$ is a complex polynomial of degree $$n$$, then closed disk D that contains at least $$n-1$$ of its zeros (counting multiplicity) contains at least $$\left[\frac{n-2k+1}{2} \right]$$ zeros  of its $$k$$-th derivative, provided that the arithmetical mean of these zeros is also centre of D. We also prove a variation of the classical composition theorem due to Szegö.
Antioxidant and Prooxidant Effects of Curcumin, Piperine and Semi-synthetic Amides with Antimycobacterial Activity on the Lipid Oxidation Process
Authors: Slavchev Ivaylo , Dobrikov Georgi , Momchilova Svetlana , Ren Yanliang , Slavova-Kazakova Adriana
Published: March 2024

Free radical oxidation is considered an important factor in the treatment of tuberculosis. Drugs or treatments with antioxidants are reflected in the literature but the choice of those used for tuberculosis is quite limited. Selected natural and synthetic compounds (hybrid molecules consisting of fenchane scaffold and cinnamoyl like residues attached through amide bond), possessing antimycobacterial activity were studied for their capacity to accelerate or decelerate lipid oxidation process. Three of the compounds under study showed prooxidant activity. To the best of our knowledge, this is the first report about the prooxidant activity of piperine under spontaneous autoxidation conditions. The presence of fenchane scaffold together with the 1,3-benzodioxole fragment, positively affects the activity but we can only speculate about the role of the amide part. Effect of equimolar binary mixtures with curcumin has also been studied. These new results may contribute to the search for efficient bio-antioxidant mixtures in the prevention and elimination of adverse reactions of antibacterial drugs.
Temporal Characteristics of the February 6, 2023 MW7.8, Turkey Earthquake Aftershock Sequence
Authors: Raykova Plamena , Solakov Dimcho , Simeonova Stela
Published: March 2024

The devastating earthquake with moment magnitude MW7.8, (local magnitude ML=7.5) which occurred in the East Anatolian Fault Zone, westwards of Gaziantep, Turkey on February 6, 2023 was followed by an intensive aftershock activity. Studying time distribution of aftershocks is important for understanding physics of the earthquake generation process.

In the present study temporal pattern of aftershock sequence of the 2023 MW7.8 Turkey earthquake is analyzed. Because of the factors such as location and radiation pattern and the cumulative nature of building damage, aftershocks can cause more damage than the main shock. The temporal clustering of aftershocks is a dominant non-random element of the seismicity, so when the clusters are removed, the remaining activity can be modelled (as first approximation) as a Poisson process.

On the assumption that aftershocks are distributed in time as a non-stationary Poisson process, we use the maximum likelihood method for estimating the parameters (K, c and p) of the modified Omori formula. For testing the goodness of fit between the aftershock occurrence and different statistical models, a transformation from the time scale t to a frequency-linearized time scale τ  is applied. Akaike's information criteria is used to select the best model for the temporal distribution of aftershocks.

It has been found that temporal distribution of the 2023 Turkey earthquake aftershocks is dominated by the classic power law decay in time and suggests the existence of secondary aftershock activity.
Differences and Intersections in Renal Biopsy Findings in Patients with Asymptomatic Hyperuricemia and Gout
Authors: Gancheva Rada , Hristova Maria , Kundurzhiev Todor , Yankova Petya , Nikolova Milena , Koundurdjiev Atanas
Published: March 2024

The aim of this study is to establish the association between asymptomatic hyperuricemia and gout with morphological and immunofluorescent changes in the renal biopsy. A total of 64 patients, 46 with asymptomatic hyperuricemia and 18 with gout were included in this retrospective study. Renal biopsy findings, clinical and laboratory data were analyzed by using medical documentation. We did not find a significant difference in the distribution of chronic renal failure between the two groups. In the gout group, the proportion of patients with nephrolithiasis was higher (p <0.001), and the presence of erythrocyturia was more common (p = 0.047). The percentage of damaged glomeruli (p = 0.249) and the distribution of mesangial proliferation (p = 0.536) was similar in the groups. The proportion of patients with interstitial fibrosis > 50$% was significantly higher in the gout group (p = 0.032), but no difference was observed in the distribution of tubular atrophy > 50% (p = 0.183). In subjects not receiving urate-lowering therapy, serum uric acid levels were comparable in the different stages of tubular atrophy and interstitial fibrosis. We found that in both asymptomatic hyperuricemia and gout, there is a deposition of immune deposits subepithelially, subendothelially, in the mesangium and in the vessel walls. In gout, the kidneys are affected to a much greater extent. We consider that not only the increased serum uric acid is important, but also monosodium urate crystals deposited in the renal interstitium causing a chronic inflammatory process followed by fibrosis. We suggest that the activation of the innate immune system by soluble uric acid and crystals with the subsequent development of a proinflammatory state in the body has led to the activation of complement and deposition of immune deposits in the kidneys.
Serum Fructosamine as a Marker for Glycemic Control in Patients with Diabetic Nephropathy
Authors: Vasileva Bilyana , Gatev Evan , Aleksandrov Aleksander , Kerezieva Simona , Ilieva Siyana , Popova Daniela , Vasilev Vasil , Niwa Toshimitsu , Mironova Roumyana , Deliyska Boryana , Tsekovska Rositsa
Published: March 2024

Diabetes mellitus (DM) is a metabolic disease of chronic insulin deficiency or resistance. The progression of DM is associated with long-term damage to macro- and micro-vascular body systems and causes serious health complications. Up to 40% of DM patients develop chronic kidney disease (CKD), mainly as a consequence of diabetic nephropathy (DN). Hence, strict glycemic control is recommended to slow down CKD progression. Hyperglycemia causes complications in diabetic patients through the glycation of various proteins. The interaction of glucose with the free NH2 groups of proteins results in the formation of the early glycation product fructosamine (FA). FA has a short half-life (1 to 2 weeks) and hence it has the potential of an early marker for glycemic control. Although long used in the clinical practice, the FA diagnostic and prognostic significance remains questionable. In this study, we tested the FA potential to serve as a glycemic marker in DM patients with DN. We found that DM patients have significantly higher serum FA levels than non-diabetics. Further, the serum FA level in diabetics correlates positively with the blood glucose concentration. Finally, the mean serum FA level was higher in DM patients with DN, compared to those without DN. These results establish FA as a promising marker for glycemic control in DN patients.
Protective Effect of Turmeric against Aluminium-induced Prostate Damage in Rats
Authors: Boudou Farouk , Belakredar Amal , Bendahmane-Salmi Malika
Published: March 2024

This study investigates the potential protective properties of turmeric (Curcuma longa L.) against aluminium (Al) toxicity-induced prostate damage in male rats. The administration of AlCl3 to rats resulted in decreased body weight, increased oxidative stress markers, hormonal depletion, apoptosis induction, and pro-inflammatory cell infiltration in the prostate tissue. Additionally, histopathological examination revealed various abnormalities. However, co-treatment with turmeric extract improved body weight, increased testosterone levels, reduced apoptosis, and mast cell infiltration. C. longa L. exhibited strong antioxidant and anti-inflammatory effects, highlighting its potential as a phytomedicine against reproductive disorders like prostatitis induced by Al exposure.
Effect of Nano-silicon Application on Salt Tolerance of Pepper (Capsicum annuum L.)
Authors: Kusvuran Sebnem , Cengil Bekir , Mutlu Ferhat
Published: March 2024

The effectiveness of nano-silicon (nSi) in increasing salt tolerance in pepper was investigated. Commercial varieties of Mızrak were used as material. To stress the plants, 4 salt doses, namely 0 (control), 50, 100, and 150 mM NaCl, were used, and 0, 0.5, 1, 2, and 3 mM doses of nSi were sprayed on the plants every seven days. Malondialdehyde (MDA), chlorophyll a and b, total carotenoid, and enzymatic activity were examined. NaCl treatment led to decreases in photosynthetic pigment contents (chlorophyll a and b, total carotenoid). NSi applications significantly increased superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase activity. However, MDA content was significantly decreased. The results support foliar application of nSi to increase the defense system of pepper, which enables it to tolerate the negative effects induced by salinity.
Protein language model-embedded geometric graphs power inter-protein contact prediction
Authors: Si Yunda , Yan Chengfei
Published: April 2024

Accurate prediction of contacting residue pairs between interacting proteins is very useful for structural characterization of protein–protein interactions. Although significant improvement has been made in inter-protein contact prediction recently, there is still a large room for improving the prediction accuracy. Here we present a new deep learning method referred to as PLMGraph-Inter for inter-protein contact prediction. Specifically, we employ rotationally and translationally invariant geometric graphs obtained from structures of interacting proteins to integrate multiple protein language models, which are successively transformed by graph encoders formed by geometric vector perceptrons and residual networks formed by dimensional hybrid residual blocks to predict inter-protein contacts. Extensive evaluation on multiple test sets illustrates that PLMGraph-Inter outperforms five top inter-protein contact prediction methods, including DeepHomo, GLINTER, CDPred, DeepHomo2, and DRN-1D2D_Inter, by large margins. In addition, we also show that the prediction of PLMGraph-Inter can complement the result of AlphaFold-Multimer. Finally, we show leveraging the contacts predicted by PLMGraph-Inter as constraints for protein–protein docking can dramatically improve its performance for protein complex structure prediction.
Improving the educational experience on Youtube: a machine learning approach to classifying and recommending educational videos
Authors: Carvalho Henrique Carlos Fonte Boa , Dorça Fabiano Azevedo , Pitangui Cristiano Grijó , Andrade Alessandro Vivas , Assis Luciana Pereira de , Trindade Eduardo Augusto Costa
Published: April 2024

The fast development of technology has revolutionized social interaction and enabled easy access to a vast amount of information. However, it is increasingly challenging to find relevant educational materials within the large volume of available data. This challenge has led to a significant waste of time for teachers and students in searching for high-quality educational resources. In this sense, the present work focuses on classifying educational videos on YouTube using Machine Learning models. The study extends a previous work that analyzed YouTube videos and proposed a methodology for classifying them using their comments. The current study expands the dataset used in the previous work and employs Machine Learning algorithms such as Random Forest and Neural Networks, along with hyperparameter tuning techniques like Grid Search. Experimental results showed that a Convolutional Neural Network was able to differentiate educational videos from non-educational ones with an accuracy rate of 95,71%. This study highlights the potential of Convolutional Neural Networks in classifying educational content on YouTube, contributing to advances in the field of Machine Learning for educational purposes.
Exploring Reproductive Health Knowledge and Practices of Female Students under 24 Years: A Study at the University of Dschang Main Campus
Authors: Alain Djam Chefor , Meli Michaela Josée , Kepgang Evrard , Choupo Gile Loïc Kongne , Ngandjui Bobby Stéphane Siewe , Saha Roddy Yvain
Published: April 2024

Context: Reproductive health encompasses people’s freedom and ability to procreate and have a sexual life that is not only safe but also satisfying. Identifying factors related to the under-utilization of reproductive health services among young girls could help reduce the incidence of reproductive health problems affecting them.
Methods: This was a cross sectional study carried out from January to July 2022 among the female students aged 24years and below of the University of Dschang’s main campus. The sampling method was proportionate stratified sampling. Categorical and continuous variables were expressed as frequencies and means respectively. Multiple logistic regression was used to assess the relationship between dependent and independent variables.
Results: A total of 395 participants were recruited, with a mean age of 20.6 years and a reported high level of knowledge about reproductive health at 88.9%. Furthermore, 56.2% of the respondents were already sexually active, with the average age at first sex being 18.8 years. However, 30.6% of the participants had made use of reproductive health services. Being aged 21-22 years and being of a religion other than Christianity were some of the predictors of the participants' knowledge and practices towards reproductive health services.
Conclusion: This study highlights the low use of reproductive health services among female students and provides new grounds for implementing interventions that will not only improve their reproductive health status but will also be culturally appropriate.
Growth of tetrakis thiourea potassium iodide as new second order optical material
Authors: Prakash J. Thomas Joseph , Vijayan N. , Kumararaman S.
Published: January 2008

A novel organometallic nonlinear optical (NLO) crystal, namely thiourea complex of tetrakis thiourea potassium iodide (TTPI), has been grown by slow evaporation solution growth technique. The harvested crystal is large in size. To our knowledge there is no report is available for the bulk size single crystal of TTPI. This material has a positive temperature coefficient and has been grown by slow evaporation solution growth technique. The grown crystal have been characterized by employing several techniques such as single crystal and powder X‐ray diffraction, FTIR, UV‐Vis‐NIR spectra, thermo gravimetric analyses respectively. Etching studies have also been carried out in order to know the surface defects on the as grown specimen of TTPI. The relative second harmonic generation efficiency have been tested by using Nd:YAG laser as source. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth, optical and thermal studies of nonlinear optical L‐arginine perchlorate single crystals
Authors: Kalaiselvi D. , Kumar R. Mohan , Jayavel R.
Published: January 2008

A potentially useful semiorganic nonlinear optical (NLO) material, L‐arginine perchlorate, has been synthesized and bulk crystals have been grown by slow cooling technique. The grown crystals were characterized by single crystal X‐ray diffraction, UV‐Vis‐NIR spectroscopy, FT‐IR, thermal analysis and SHG measurements. The grown crystals were thermally stable upto 153°C and exhibit SHG efficiency of about 0.17 with respect of Urea. The etching studies have been carried out on the grown crystal. LAPC has good optical transmission not only in the visible range, however, also in the near UV part of the spectra and hence it is a potential material for nonlinear frequency conversion. The refractive index was measured by the Brewster's angle method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reciprocal‐influence mediation model: A guide for practice and research
Authors: Sinclair Lucinda E. , Stuart William D.
Published: January 2008

Because of the length of most mediation sessions, it is challenging to assess a session's turn‐by‐turn nature. Here, a reciprocal‐influence model is presented that views mediation as a dynamic, interdependent system that recognizes individual utterances of disputants and media‐tors that change or reinforce destructive conflict. This perspective gives rise to a research method that maps the mediation discourse at a micro‐level in order to track each member's constructive and destructive state‐ments and view their mutual influence on the system as well as changes within the system over time. This process then facilitates a closer exam‐ination of critical shifts that lead to integrative conflict or resolution among the disputants. These closer examinations also indicate more‐and less‐effective client‐responsive interventions posed by the mediator.
Caged Amino Acids for Visible‐Light Photodelivery
Authors: Salierno Marcelo , Fameli Cecilia , Etchenique Roberto
Published: January 2008

We present a photocleavable protecting group based on ruthenium bipyridyl complexes and suitable for amino acid photodelivery. We discuss the photochemical properties of the caged glutamate, which is a major neurotransmitter in the CNS. The molar absorptivity for the caged glutamate at 450 nm is ϵ = 4200 M–1 cm–1 and its quantum yield of photorelease at 450 nm is ΦPD = 0.035, which is about 17 times higher than that of the most active organic caged compound at this wavelength. Similar figures are obtained for other α‐amino acids. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Toxoplasma gondii ferredoxin‐NADP+ reductase: Role of ionic interactions in stabilization of native conformation and structural cooperativity
Authors: Singh Kulwant , Bhakuni Vinod
Published: January 2008

The apicoplast and the proteins present therein are parasite‐specific targets for chemotherapy of apicomplexan parasites. Ferredoxin‐NADP+ reductase (FNR) is an important enzyme present in the apicoplast of Toxoplasma gondii that operates as a general electron switch at the bifurcation step of many different electron transfer pathways. In spite of its importance as drug target not much structural information on the enzyme is available. Using fluorescence and CD spectroscopy in combination with enzyme activity measurement and size exclusion chromatography, we studied the pH‐dependent changes in structural and functional properties and interdomain interactions in recombinant Toxoplasma gondii ferredoxin‐NADP+ reductase (TgFNR) to understand the interactions responsible for stabilization of native conformation and modulation of functional activity of the enzyme. Under physiological conditions, the recombinant TgFNR is stabilized in an open conformation. The open conformation of the enzyme was found to be essential for its optimum functioning, as induction of compactness/rigidity by modulation of pH, leads to decrease in the functional activity. In native conformation, strong interactions exist between the NADP+‐ and FAD‐binding domains thus making the enzyme a structurally cooperative molecule. Under acidic conditions (pH about 4), the interdomain interactions present in native TgFNR were lost and the enzyme became structurally noncooperative. The pH‐induced structural alterations in the NADP+ binding domain, more precisely compaction of the conformation lead to its stabilization against thermal denaturation. The studies demonstrate the significance of electrostatic interactions both in stabilization of native conformation and maintenance of structural cooperativity in TgFNR. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Identifying folding nucleus based on residue contact networks of proteins
Authors: Li Jie , Wang Jun , Wang Wei
Published: January 2008

In the native structure of a protein, all the residues are tightly parked together in a specific order following its folding and every residue contacts with some spatially neighbor residues. A residue contact network can be constructed by defining the residues as nodes and the native contacts as edges. During the folding of small single‐domain proteins, there is a set of contacts (or bonds), defined as the folding nucleus (FN), which is formed around the transition state, i.e., a rate‐limiting barrier located at about the middle between the unfolded states and the native state on the free energy landscape. Such a FN plays an essential role in the folding dynamics and the residues, which form the related contacts called as folding nucleus residues (FNRs). In this work, the FNRs in proteins are identified by using quantities which characterize the topology of residue contact networks of proteins. By comparing the specificities of residues with the network quantities KR, LR, and DR, up to 90% FNRs of six typical proteins found experimentally are identified. It is found that the FNRs behave the full‐closeness centrals rather than degree or closeness centers in the residue contact network, implying that they are important to the folding cooperativity of proteins. Our study shows that the FNRs can be identified solely from the native structures of proteins based on the analysis of residue contact network without any knowledge of the transition state ensemble. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Kinetic models for mechanoenzymes: Structural aspects under large loads
Authors: Tsygankov Denis , Fisher Michael E.
Published: January 2008

A broad class of chemical kinetic model for mechanoenzymes is analyzed theoretically in order to uncover structural aspects of the underlying free-energy landscape that determine the behavior under large resisting and assisting loads, specifically the turnover rate or, for a translocatory motor protein, the mean velocity, say, V. A systematic graphical reduction algorithm is presented that provides explicit analytical expressions for mean occupation times in individual biomechanochemical states, for the splitting or backward/forward fractions, for the overall mean dwell time, and for the turnover rate. Application to the previously studied N-state sequential and (Nα,Nβ)-parallel-chain models provides explicit structural criteria (independent of the zero-load transition rates) that determine whether ∣V∣ diverges to large values or, conversely, exhibits extrema and converges to a vanishing value as the externally imposed load grows. Closed-form analytical extensions accommodate side-chain and looped side-chain reaction sequences in the enzymatic cycle. A general divided-pathway model is analyzed in detail.
Prediction of rise velocity of a liquid Taylor bubble in a vertical tube
Authors: Mandal T. K. , Das G. , Das P. K.
Published: January 2008

In the present study, a theoretical analysis has been performed to predict rise velocity of liquid Taylor bubbles. The viscous potential flow analysis has been adopted for this purpose. The results have revealed the importance of nose shape. This has been quantified by a shape factor. A method for estimating this factor has also been proposed.
Identification of single and coupled acceptors in silicon nano-field-effect transistors
Authors: Khalafalla M. A. H. , Ono Y. , Nishiguchi K. , Fujiwara A.
Published: January 2008

We performed dopant mediated hole transport measurements to identify the depth position of individual boron acceptors and investigate two-acceptor coupling in silicon-on-insulator nanoscale field-effect transistors at a temperature of 6K. The depth position is qualitatively obtained from the analysis of the acceptor-to-gate capacitances. We also observe signatures of a two-acceptor capacitive coupling in the characteristics of the conductance versus the front and back gate voltages.
Photoacoustic Doppler flow measurement in optically scattering media
Authors: Fang Hui , Maslov Konstantin , Wang Lihong V.
Published: January 2008

We recently observed the photoacoustic Doppler effect from flowing small light-absorbing particles. Here, we apply the effect to measure blood-mimicking fluid flow in an optically scattering medium. The light scattering in the medium decreases the amplitude of the photoacoustic Doppler signal but does not affect either the magnitude or the directional discrimination of the photoacoustic Doppler shift. This technology may hold promise for a new Doppler method for measuring blood flow in microcirculation with high sensitivity.
Design of efficient organic tandem cells: On the interplay between molecular absorption and layer sequence
Authors: Dennler Gilles , Forberich Karen , Ameri Tayebeh , Waldauf Christoph , Denk Patrick , Brabec Christoph J. , Hingerl Kurt , Heeger Alan J.
Published: January 2008

We have carried out detailed optical simulations of tandem solar cells based on the following organic semiconductors: poly(3-hexylthiophene) (P3HT), poly[2,6-(4,4-bis-(2-ethylhexyl)-4H- cyclopenta[2,1-b;3,4-b′]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT), 1-(3- methoxycarbonyl) propyl-1-phenyl[6,6] C61 (PC60BM), and 1-(3-methoxycarbonyl) propyl-1- phenyl[6,6] C71 (PC70BM). We demonstrate that out of the many possible combinations of the component materials, one specific combination emerges as the best to reduce the spectral overlap of the two bulk heterojunction blends and thereby to ensure an optimized short-circuit current density (Jsc). Furthermore, the calculations allow us to predict the maximum Jsc achievable in tandem cells based on P3HT and PCPDTBT. Finally, we show that the efficient tandem cell realized and described recently by Kim et al. [Science 317, 222 (2007)] ensures balanced absorption in the top and bottoms cells.
Temperature-dependent photoluminescence properties of synthesized schistoselike organic nanostructures
Authors: Chen Yujie , Chen Xudong , Yu Dingshan , Li Baojun , He Zhiqiu , Li Guangji
Published: January 2008

Schistoselike organic nanostructures were synthesized via a simple hydrothermal method. Optical properties of the nanostructures have been investigated by temperature-dependent photoluminescence (PL) spectroscopy. Three PL peaks were observed and their positions can be tuned by temperature from visible to ultraviolet region. The Huang-Rhys factor of the PL spectrum was calculated and an extended empirical model of the Bose-Einstein statistical factor concerning phonon emission and absorption was applied to investigate the PL behavior. The emission dynamic behaviors of the organic nanostructures were studied by PL decay curve, indicating two lifetime components of 0.80 and 6.98 μs at 300 K.
Energy-based quasi-static modeling of the actuation and sensing behavior of single-crystal iron-gallium alloys
Authors: Atulasima Jayasimha , Flatau Alison B. , Cullen James R.
Published: January 2008

An energy based model [W. D. Armstrong, J. Appl. Phys. 81, 2321 (1997); J. Atulasimha, Ph.D. thesis, Aerospace Engineering, University of Maryland, College Park, MD, 2006] is employed to predict the actuation (λ−H and B−H at various compressive stresses) and sensing behavior (B−σ and ε−σ at various bias fields) of single-crystal FeGa alloys. The significant feature of this formulation is that, in addition to modeling actuation behavior, the sensing behavior can be predicted based on parameters estimated from the actuator characteristics. These predictions are then validated against experimental data for furnace cooled 19 at. % [100] oriented single-crystal FeGa alloys. Furthermore, an attempt is made to couple the energy-based sensing model with a lumped-parameter model that simulates the magnetic interaction between the magnetostrictive specimen and the magnetic circuit comprising the transducer. This enables a prediction of the variation in field through the sample due to changes in reluctance of the magnetostrictive sample with stress, as well as the impact of this variation in field on the B−σ and ε−σ curves. These predictions are benchmarked against experimental data, wherein the bias field varies due to change in sample reluctance with application of compressive stress while the drive current to the transducer is maintained constant.
Remote phonon scattering in field-effect transistors with a high κ insulating layer
Authors: Laikhtman B. , Solomon P. M.
Published: January 2008

In this paper a remote phonon scattering of channel electrons in a field-effect transistor (FET) with a high dielectric constant (κ) insulator in between the gate and the channel is studied theoretically. The spectrum of phonons confined in the high κ layer and its modification by the gate screening is investigated. Only two phonon modes of five participate in the remote electron-phonon scattering. The gate suppresses one of the modes but increases scattering by the other. Numerical results for the channel mobility limited only by remote phonon scattering were obtained for a Si FET with a HfO2 layer and a SiO2 layer in between the channel and metallic gate. A surprising result is the reduction of the mobility compared to the case when the gate screening is absent. The dependence of the mobility on the widths of HfO2 and interfacial SiO2 layers on channel concentration and temperature was studied. The accuracy of the calculations based on the Boltzmann equation is discussed. Finally, a comparison of our results with available experimental data leads to the conclusion that the remote phonon scattering is not the dominating scattering mechanism.
Zinc oxide nanorods grown on two-dimensional macroporous periodic structures and plane Si as a pH sensor
Authors: Al-Hilli Safaa M. , Al-Mofarji R. T. , Klason P. , Willander M. , Gutman N. , Sa'ar A.
Published: January 2008

p H determination is a strong prerequisite for many biochemical and biological processes. We used two methods, namely, the electrochemical potential method (experimental) and site binding method (theoretical), to study the sensitivity of zinc oxide (ZnO) nanorods grown on two-dimensional macroporous periodic structures (2DMPPS) (p-and n-type) and plane n-type Si substrates for use as an intracellular pH sensing device. The dimension of these nanorods varied in radius between 50 and 300 nm and lengths of 1–10 μm. We found that the sensitivity of ZnO nanorods increases with reductions in size, from 35 mV/pH for D=300 nm and L=10 μm, to 58 mV/pH for D=50 nm and L=1 μm, using the site binding model. The experimental electrochemical potential difference for the ZnO nanorods working electrode versus Ag/AgCl reference electrode showed a high sensitivity range for ZnO nanorods grown on 2DMPPS n-Si substrate as compared to plane n-Si at room temperature for pH ranging from 4 to 12 in buffer and NaCl solutions.
Electronic transport and magnetoresistance in ultrathin manganite-titanate junctions
Authors: Xie Y. W. , Sun J. R. , Han Y. N. , Shen B. G.
Published: January 2008

We present a systematic study on the rectifying behaviors of the heterojunctions composed of a ultrathin La0.67Sr0.33MnO3 film (∼2nm in thickness) and a SrTiO3 substrate doped by 0.05 or 1wt% Nb. These junctions exhibit excellent rectifying behaviors and a remarkable bias-dependent magnetoresistance (up to 60% under a field of 5T). The transport behaviors are dominated by thermal process and tunneling process for the junctions with low and high Nb contents, respectively.
Growth and characterization of GaP nanowires on Si substrate
Authors: Zhang G. , Tateno K. , Sogawa T. , Nakano H.
Published: January 2008

The integration of III-V semiconductor materials with Si technology is of great interest for optoelectronic integration circuits. We have studied the growth and structural aspects of GaP nanowires (NWs) grown on Si substrate in a metalorganic vapor phase epitaxy system. Au colloid particles dispersed on Si substrate were used as catalysts to conduct the NW growth. The growth temperature considerably affected the growth rate and shape of GaP NWs. The growth rate showed a maximum value of 14.69nm∕s at 480°C. When growth temperature increased the radial growth on NW sides was enhanced and the NWs therefore exhibited a tapering shape. GaP NWs with a uniform diameter could be grown at a growth temperature as low as 420°C using a two-temperature process. The NW diameter could be well controlled by using size-selective Au colloid particles. The growth rate dependence showed that the thin NWs grew more slowly than thick ones and the V∕III source ratio had a significant effect on the growth rate dependence. An analysis of the GaP∕Si interface by transmission electron microscopy indicated that the NWs were epitaxially grown on the Si(111) substrate. Based on these experimental results, the growth mechanism of the GaP NWs on Si was discussed.
Charge storage characteristics in metal-oxide-semiconductor memory structure based on gradual Ge1−xSix∕Si heteronanocrystals
Authors: Lu Jin , Zuo Zheng , Chen Yubin , Shi Yi , Pu Lin , Zheng Youdou
Published: January 2008

Charge storage characteristics in the metal-oxide-semiconductor memory structure based on gradual Ge1−xSix∕Si heteronanocrystals (HNCs) have been investigated by using capacitance-voltage measurements. The gradual Ge1−xSix∕Si HNCs on ultrathin SiO2 were fabricated through combining self-assembled growth and selective chemical etching technique. The observations demonstrate that the holes reach a longer retention time even with an ultrathin tunnel oxide, owing to the high band offset at the valence band between Ge and Si.
Controllable switching of vortex chirality in magnetic nanodisks by a field pulse
Authors: Gaididei Yuri , Sheka Denis D. , Mertens Franz G.
Published: January 2008

We propose a way of fast switching the chirality in a magnetic nanodisk by applying a field pulse. To break the symmetry with respect to clockwise or counterclockwise chirality, a mask is added by which an inhomogeneous field influences the vortex state of a nanodisk. Using numerical spin-lattice simulations, we demonstrate that chirality can be controllably switched by a field pulse, whose intensity is above some critical value. A mathematical definition for the chirality of an arbitrary shaped particle is proposed.
Around-the-Clock, Rapid Diagnosis of Influenza by Means of Membrane Chromatography Antigen Testing Confirmed by Polymerase Chain Reaction
Authors: Nilsson Anna C. , Alemo Birgitta , Björkman Per , Dillner Lena , Melhus Åsa , Nilsson Berit , Widell Anders
Published: January 2008

One rapid membrane chromatography test and 2 immunofluorescence tests were compared with polymerase chain reaction as tools for the diagnosis of influenza in 277 patients treated in an emergency department. The sensitivity on days 1-3 of symptoms was 71% for the rapid membrane chromatography test, 70% for the first immunofluorescence test, and 79% for the second immunofluorescence test. Rapid tests are useful for round-the-clock identification of influenza, with follow-up polymerase chain reaction used for confirmation.
Marine mineral resources
Authors: CRONAN D.S.
Published: January 2008

Oceanic manganese nodules, for long the cornucopia of sea floor mineral deposits, have lost much of their economic attractiveness in recent years as a result of depressed metal prices and difficulties surrounding their potential extraction under the Law of the Sea Convention. In their place, commerical interest in mineral deposits within Exclusive Economic Zones has increased, while the scientific world is enamoured with the black smokers discharging at mid–ocean ridges and the polymetallic sulphides that precipitate from them.
Searching for metals in the 1980s
Authors: EARLE STEVEN
Published: January 2008

The past four decades have seen an unprecedented development of metal exploration techniques because as exposed and easily exploitable mineral deposits have been used up, exploration geologists have been forced to find new ways of looking deeper into the crust.
Mass mortalities of Devonian fish – the Achanarras Fish Bed, Caithness
Authors: TREWIN NIGEL H.
Published: January 2008

The fossil fish found so beautifully preserved in the Middle Devonian Achanarras Fish Bed of northern Scotland drifted to their final resting place following mass mortalities caused by deoxygenation of lake waters.
Tailor–made geology 1: General introduction and Salthill Quarry, Lancashire
Authors: DUFF KEITH
Published: January 2008

The protection and long‐term safeguarding of geological localities are fundamental to the continuation of fieldwork, both now and in the future. The responsibility for these lies with the Nature Conservancy Council, the government agency charged with protecting geological and biological sites. Part of the work of the Council's Geology Branch is concerned with creating or re‐exposing geological localities which are of value for teaching or collecting; and in the article which follows, Keith Duff explains the background and methods of this work, using the recently established geological trail at Salthill Quarry in Lancashire as as example. This is the first of a series of articles which will give details of British sites developed in this way.
Ordovician volcanoes in Britain and Ireland
Authors: STILLMAN C.J.
Published: January 2008

The intense volcanic activity of Ordovician times can be explained in terms of the type of plate‐tectonic processes occurring today. Whenever plate tectonics is vigorous, so is volcanism.
The blueschist enigma
Authors: WINTSCH SUSAN
Published: January 2008

Plate tectonics, the new view of Earth dynamics that took shape in the late 1960s, has steadily gained strength over the past IS years. The vast majority of geologists now picture the Earth's outer shell not as a single, solid sheath, but as a jigsaw of shifting plates, whose movements are called upon to explain everything from mountains to the mineral make‐up of individual rocks. Emerging plate‐tectonics models revolutionised the very approach to geologic problems. One of the early fruits of this powerful and intellectually fertile theory was a new understanding of‘blueschists’, rocks named for their finely layered, or schistose, structure and for the characteristic colour and nature of their mineral grains.
The future of the ‘Geological Museum’
Authors: DUNNING FRED
Published: January 2008

The following letter was written for, and has already been published in, the Geologists' Association Circular; but because it represents an important contribution to issues rehearsed in these columns, the editor of the Circular and the author have kindly agreed to its re‐publication here.
Purchasing satellite imagery for geological applications
Authors: JONES ALUN C.
Published: January 2008

The attractiveness of remotely sensed data to aid in the interpretation of global and local environmental processes has been widely recognized. However, some of the most common and frustrating, yet simple, questions that are asked by potential users of remotely sensed data are what images are available, from whom, and, most importantly, how much do t h q cost? As cost is often critical in deciding whether satellite imagery is to be used in a project, it is important to determine what benefits can be obtainedfrom the use of such data. These questions are examined here in the context of obtaining remotely sensed Landsat and SPOT imagery for monitoring a spectral and spatial dynamic geological feature, namely, an active volcano, Mt Etna, Sicily.
The latest vertebrates are the earliest
Authors: ALDRIDGE RICHARD J. , BRIGGS DEREK E. G. , SANSOM IVAN J. , SMITH M. PAUL
Published: January 2008

The teeth, or elements, ofconodonts are among the most important Palaeozoic microfossils. Despite this, the biological relationships of conodonts have long remained enigmatic. Recent evidence of their soft anatomy, and of the ultrastructure of the elements, has finally revealed that they are vertebrates. These discoveries push vertebrate origins firmly back into the Cambrian and add a large cohort of specialists to the ranks of the vertebrate palaeontologists.
Detectives and geology in fiction ‐ 1: Holmes and Thorndyke
Authors: SARJEANT WILLIAM A. S.
Published: January 2008

In the early years ‐ the so called ‘Golden Age’ ‐ of mystery fiction, there were a number of towering figures ‐ the ‘great detectives’. However, only two of them included geology among their concerns. Their abilities and achievements are here compared and assessed.
Exotic marbles on Cheshire cheese: High‐street geology in Bath
Authors: DOVE JANE
Published: January 2008

Most shoppers in Bath ignore the cladding on the front of the‘Co‐op’. Those pausing to look probably consider it marble. In fact, it is Larvikite, a type of syenite commonly used to clad high‐street stores throughout Britain. A survey of shop fronts, banks and other services in this city reveals a wide variety of exotic imported marbles and granites attached to local Bath Stone at street level. Modern stone cladding is also found to extend beyond the post‐war shopping area. Stromatolitic limestones and porphyritic granites peep out beneath Victorian shop windows in Milsom Street. Moreover, not all the cladding in this street is found to be modern. Scottish and Shap Granites, introduced into Bath in the nineteenth century, clad former banks and a Victorian department store.
PREPARATION AND PROPERTIES OF PHOTOPRODUCTS OF OROTIC ACID ANALOGUES*
Authors: Sztumpf Eva , Shugar D.
Published: January 2008

Abstract— Irradiation of orotic acid or 3‐methylorotic acid in liquid medium in the quartz U.V. leads to formation of photoproducts which have been shown to be dimers similar to those formed from uracil or thymine in frozen solution. The dimers are subject to photo‐dissociation in the same wavelength range, so that at any given wavelength there is a stationary equilibrium between dimer formation and dissociation. The equilibrium point is also dependent on concentration, and on pH, the dimerization reaction being more rapid for the neutral forms. For both compounds there is an appreciable oxygen effect, which inhibits dimer formation.

I‐methylorotic acid and 1,3‐dimethylorotic acid also dimerize, but the oxygen effect is diminished as a result of alkylation on the N1 ring nitrogen.

5‐methylorotic acid is radiation resistant in liquid medium, but readily dimerizes in frozen medium; the subsequent photodissociation of this dimer in liquid medium is unaffected by oxygen.

Orotidine forms several photoproducts of which one, about 20 per cent of the total, is a similar dimer.

Orotic acid methyl ester likewise dimerizes in liquid medium and exhibits an oxygen effect comparable to that for orotic acid. By contrast 5‐methylorotic acid methyl ester in liquid medium is radiation resistant at short wavelengths, but dimerizes at long wavelengths.

The dimers of orotic acid, 3‐methylorotic acid, 5‐methylorotic acid and orotidine have been isolated in crystalline form. The properties of the various photodimers are described and quantum yields for dimerization and photodissociation calculated for several of them at 254 mμ. For orotic and 3‐methylorotic acids the high quantum yields for dimerization and the appreciable oxygen effect suggest that the dimerization of these molecules proceeds via a long‐lived excited state.