bluuebunny/crossref_metadata_2025 huggingface dataset:
Uterine Rupture: Changing Trends in Obstetrics and Lessons for Obstetricians
Authors: Rabbani Tamkin Khan , Zia Shumaila , Rafique Muhammad , Rizwan Ayesha , Amin Abdel Bagi
Published: February 2013

Objectives

To determine the impact of improved obstetric care on the incidence, risk factors, management modalities and fetomaternal outcome of uterine rupture.

Materials and methods

Retrospective analysis of clinical records of uterine rupture cases at the department of Obstetrics and Gynecology, Abha General Hospital, Abha, KSA, from January 2007 to January 2012.

Outcome measures

Maternal and perinatal morbidity and mortality.

Results

Analysis showed 33 cases of uterine rupture among 34,590 deliveries, the incidence being 1/1048 (0.09%). Majority of the cases (73%) were unbooked. Important risk factors were previous cesarean section (88%) and grand multiparity (80%). Previous one C-section was also found to be an important risk factor (80%) for uterine rupture. Most of the patients were in their 30s. The frequency of complete and incomplete uterine rupture was almost the same (52 and 48% respectively). Total abdominal hysterectomy was required in 9 (27%), repair in 23 (70%) and one (3%) woman underwent subtotal hysterectomy. None of the patients agreed for tubal ligation. Seven (21%) cases were associated with bladder injury and three (9%) had vascular injury. There was no maternal mortality, 11 (33%) intrauterine fetal deaths and a live birth rate was 67%.

Conclusion

The absolute incidence of uterine rupture has not decreased inspite of the availability of ANC care and facilities for institutional deliveries. Only the etiological profile has changed. Our study found previous C-section as the most important emerging cause for uterine rupture. Reduction in Csection rate, awareness about the signs and symptoms of impending rupture, careful monitoring during induction in a scarred uterus on the part of caregivers and counseling about need for timely booking and importance of institutional delivery are important factors for reducing uterine rupture.

How to cite this article

Zia S, Rafique M, Rizwan A, Amin AB, Khan T. Uterine Rupture: Changing Trends in Obstetrics and Lessons for Obstetricians. J South Asian Feder Obst Gynae 2012;4(3):155-158.
Peripartum Cardiomyopathy: A Review of Three Case Reports
Authors: Kumari Ankita , Chaturvedi Mridul
Published: February 2013

Peripartum cardiomyopathy (PPCM) is an idiopathic cardiomyopathy that presents with heart failure secondary to left ventricular systolic dysfunction toward the end of pregnancy or in the months after delivery. Incidence of PPCM ranges from 1:300 to 1:15,000 pregnancies. Causes and pathogenesis are poorly understood. Clinical presentation includes signs and symptoms of heart failure. PPCM remains a major cause of maternal morbidity and mortality. Many cases of PPCM improve or resolve completely but others progress to heart failure; as early diagnosis and medical treatment may affect the patient's long-term prognosis. The aim of this report is to make health professionals aware of the possibilities in a woman with dyspnoea in the postpartum period.

How to cite this article

Kumari A, Singh S, Singh S, Chaturvedi M. Peripartum Cardiomyopathy: A Review of Three Case Reports. J South Asian Feder Obst Gynae 2012;4(3):164-166.
Gravitational separation in the stratosphere – a new indicator of atmospheric circulation
Authors: Ishidoya S. , Sugawara S. , Morimoto S. , Aoki S. , Nakazawa T. , Honda H. , Murayama S.
Published: February 2013

Abstract. As a basic understanding of the dynamics of the atmospheric circulation, it has been believed that the gravitational separation of atmospheric components is observable only in the atmosphere above the turbopause. However, we found, from our high-precision measurements of not only the isotopic ratios of N2, O2 and Ar but also the concentration of Ar, that the gravitational separation occurs even in the stratosphere below the turbopause; their observed vertical profiles are in good agreement with those expected theoretically from molecular mass differences. The O2/N2 ratio observed in the middle stratosphere, corrected for the gravitational separation, showed the same mean air age as estimated from the CO2 concentration. Simulations with a 2-dimensional model of the middle atmosphere indicated that a relationship between the gravitational separation and the air age in the stratosphere would be significantly affected if the Brewer-Dobson circulation is enhanced due to global warming. Therefore, the gravitational separation is usable as a new indicator of changes in the atmospheric circulation in the stratosphere.
Why could ice ages be unpredictable?
Authors: Crucifix M.
Published: February 2013

Abstract. It is commonly accepted that the variations of Earth's orbit and obliquity control the timing of Pleistocene glacial-interglacial cycles. Evidence comes from power spectrum analysis of palaeoclimate records and from inspection of the timing of glacial and deglacial transitions. However, we do not know how tight this control is. Is it, for example, conceivable that random climatic fluctuations could cause a delay in deglaciation, bad enough to skip a full precession or obliquity cycle and subsequently modify the sequence of ice ages? To address this question, seven previously published conceptual models of ice ages are analysed by reference to the notion of generalised synchronisation. Insight is being gained by comparing the effects of the astronomical forcing with idealised forcings composed of only one or two periodic components. In general, the richness of the astronomical forcing allows for synchronisation over a wider range of parameters, compared to periodic forcing. Hence, glacial cycles may conceivably have remained paced by the astronomical forcing throughout the Pleistocene. However, all the models examined here also show a range of parameters for which the structural stability of the ice age dynamics is weak. This means that small variations in parameters or random fluctuations may cause significant shifts in the succession of ice ages if the system were effectively in that parameter range. Whether or not the system has strong structural stability depends on the amplitude of the effects associated with the astronomical forcing, which significantly differ across the different models studied here. The possibility of synchronisation on eccentricity is also discussed and it is shown that a high Rayleigh number on eccentricity, as recently found in observations, is no guarantee of reliable synchronisation.
A survey of strong high-frequency sea level oscillations along the US East Coast between 2006 and 2011
Authors: Pasquet S. , Vilibić I. , Šepić J.
Published: February 2013

Abstract. A systematic survey of high-frequency sea level oscillations (<6 h) measured between 2006 and 2011 along the US East Coast is performed. Raw 1-min resolution sea level data is used. After performing a data quality check, the nine most intense events, with maximum recorded wave heights ranging from 40 to 100 cm, are identified. Focusing on three of these events enables us to recognize two different generation mechanisms: (i) topographically-trapped edge waves which are found to be a significant contributor to the strongest observed oscillations, and (ii) standing waves, which occur over enclosed shallow waters and may result in significant wave heights of up to 100 cm. A reproduction of the observed oscillations is a part of a future work, which will include an assessment of a generating force in the atmosphere, allowing for a better prevention of potential flooding along the US East Coast.
Extending MapMan Ontology to Tobacco for Visualization of Gene Expression
Authors: Ling Maurice H. T. , Rabara Roel C. , Tripathi Prateek , Rushton Paul J. , Ge Xijin
Published: February 2013

Microarrays are a large-scale expression profiling method which has been used to study the transcriptome of plants under various environmental conditions. However, manual inspection of microarray data is difficult at the genome level because of the large number of genes (normally at least 30 000) and the many different processes that occur within any given plant. MapMan software, which was initially developed to visualize microarray data for Arabidopsis, has been adapted to other plant species by mapping other species onto MapMan ontology. This paper provides a detailed procedure and the relevant computing codes to generate a MapMan ontology mapping file for tobacco (Nicotiana tabacum L.) using potato and Arabidopsis as intermediates. The mapping file can be used directly with our custom-made NimbleGen oligoarray, which contains gene sequences from both the tobacco gene space sequence and the tobacco gene index 4 (NTGI4) collection of ESTs. The generated dataset will be informative for scientists working on tobacco as their model plant by providing a MapMan ontology mapping file to tobacco, homology between tobacco coding sequences and that of potato and Arabidopsis, as well as adapting our procedure and codes for other plant species where the complete genome is not yet available.
Microstructural Observations in (Na0.5K0.5)NbO3Ceramics with CuO and ZnO Additives
Authors: Kim Young Heon , Ryu Hyun , Cho Yang-Koo , Lee Hwack-Joo , Nahm Sahn
Published: February 2013

The characterizations of CuO and ZnO pockets which had formed in (Na0.5K0.5)NbO3(NKN) matrix sintered at 920 °C with CuO of 1.5 mol % and ZnO of 1.5 and 3.0 mol % as the additives were investigated from a microstructural point of view using transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). Two types of pockets, composed of CuO and ZnO as a dominant component, were observed in the microstructure as new microstructure constituents. The abnormal grain growth has occurred by the liquid phase sintering. The pockets were melted partially or completely by the interactions with element Na in the matrix which has formed a eutectic compound whose melting point is lower than the sintering temperature. The reaction starts at the interfaces between the pocket and matrix and the kinetics depends not only on the size of the pocket but also on the environments where the pockets are located. When the additive content of ZnO was increased to 3.0 mol %, there are interactions between CuO and ZnO and both elements are found in the compound pocket. The sintering kinetics was much enhanced by the presence of both additives.
Electrochemical Characterization of Hydrothermally Synthesized Pt–Ru–Ni–P Catalyst for Direct Methanol Fuel Cell
Authors: Lee Seok-Hee , Kim Dong-Joo , Yoon Young-Soo
Published: February 2013

Pt–Ru–Ni–P/multiwalled carbon nanotube (MWCNT) catalyst is synthesized by a hydrothermal process using sodium hypophosphite (NaH2PO2) as a reducing agent. The particle size is evaluated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrocatalytic activity of a Pt–Ru–Ni–P/MWCNT catalyst for methanol electro-oxidation has been studied by cyclic voltammetry, chromoamperometry, and impedance spectroscopy. TEM images reveal that the Pt–Ru–Ni–P nanoparticles have a wide size distribution with an average size of 3.2 nm. Pt–Ru–Ni–P/MWCNT catalyst shows an electrochemically active surface area of 63.2 m2g-1and a mass activity of 187.56 mA mg Pt-1. It has been found that the presence of phosphorus as an interstitial species can enhance the dispersion as well as reduce the size of Pt–Ru–Ni–P nanoparticles. Moreover, incorporation of phosphorus into the Pt–Ru–Ni/MWCNT catalyst shows a 1.5 times higher electrocatalytic activity. The power density (57 mW cm-1) of the Pt–Ru–Ni–P/MWCNT catalyst in fuel cell tests is higher than that (40 mW cm-1) of the Pt–Ru–Ni/MWCNT catalyst.
Structural Deformation of Graphene–Nanotube Contacts: First-Principles Simulations
Authors: Ma Wanli , Zhang Gang
Published: February 2013

By using first-principles simulations, we studied the geometry deformation of few-layer graphene and single-walled carbon nanotube (SWNT) contact. With SWNT on the graphene, the graphene interlayer spacing reduces. Moreover, there is a dip appears in the topmost graphene layer due to the interaction with SWNT. The depth of this dip increases with SWNT diameter. And geometry deformation is also observed in thin SWNT. We demonstrate that even for very thin SWNT, the geometry deformation and flexibility of both graphene layer and SWNT cannot be ignored, which will lead to atomic scale locking of the nanotube on graphene. Thus the contact between SWNT and graphene is more stable than expected.
Graphene Manipulation on 4H-SiC(0001) Using Scanning Tunneling Microscopy
Authors: Xu Peng , Ackerman Matthew L. , Barber Steven D. , Schoelz James K. , Qi Dejun , Thibado Paul M. , Wheeler Virginia D. , Nyakiti Luke O. , Myers-Ward Rachael L. , Jr. Charles R. Eddy, , Gaskill D. Kurt
Published: February 2013

Atomic-scale topography of epitaxial multilayer graphene grown on 4H-SiC(0001) was investigated using scanning tunneling microscopy (STM). Bunched nano-ridges ten times smaller than previously recorded were observed throughout the surface, the morphology of which was systematically altered using a relatively new technique called electrostatic-manipulation scanning tunneling microscopy. Transformed graphene formations sometimes spontaneously returned to their original morphology, while others permanently changed. Using an electrostatic model, we calculate that a force up to ∼5 nN was exerted by the STM tip, and an energy of around 10 eV was required to alter the geometry of a ∼100×200 nm2 area.
Si1-yGey or Ge1-zSnz Source/Drain Stressors on Strained Si1-xGex-Channel P-Type Field-Effect Transistors: A Technology Computer-Aided Design Study
Authors: Eneman Geert , Keersgieter An De , Witters Liesbeth , Mitard Jerome , Vincent Benjamin , Hikavyy Andriy , Loo Roger , Horiguchi Naoto , Collaert Nadine , Thean Aaron
Published: February 2013

The interaction between two stress techniques, strain-relaxed buffers (SRBs) and epitaxial source/drain stressors, is studied on short, Si1-x
Ge
x
- and Ge-channel planar transistors. This work focuses on the longitudinal channel stress generated by these two techniques. Unlike for unstrained silicon-channel transistors, for strained channels on top of a strain-relaxed buffer a source/drain stressor without recess generates similar longitudinal channel stress than source/drain stressors with a deep recess. The least efficient stress transfer is obtained for source/drain stressors with a small recess that removes only the strained channel, not the substrate underneath. These trends are explained by a trade-off between elastic relaxation of the strained-channel during source/drain recess and the increased stress generation of thicker source/drain stressors. For Ge-channel pFETs, GeSn source/drains and Si1-x
Ge
x
strain-relaxed buffers are efficient stressors for mobility enhancement. The former is more efficient for gate-last schemes than for gate-first, while the stress generated by the SRB is found to be independent of the gate-scheme.
A Simple Circuit to Investigate Threshold Voltage Variation and Its Application in Monitoring Negative Bias Temperature Instability Degradation
Authors: Hong Jie , He Yandong , Zhang Ganggang , Zhang Xing
Published: February 2013

This paper presents a test circuit which can be used to analyze the p-MOSFET threshold voltage (V
T) shift and fluctuation. The proposed circuit includes two p-MOSFETs, series connection. Using the circuit, we can directly measure threshold voltage shift on the output side and gather fluctuation statistics of p-MOSFET devices. The principle and the sensitivity of this method are demonstrated, followed by simulation and experimental results. A predictive model of negative bias temperature instability (NBTI) is introduced to analyze the PMOS degradation under constant stress. The NBTI stress experimental results have shown that this circuit can monitor NBTI degradation accurately, and offer a significant improvement in efficiency over existing I
d–V
g methods.
Characteristics of Lateral Diffused Metal–Oxide–Semiconductor Transistors with Lightly Doped Drain Implantation through Gradual Screen Oxide
Authors: Yan Chin-Rung , Chen Jone F. , Lin Chung-Yi , Hsu Hao-Tang , Liao Yu-Jie , Yang Min-Ti , Chen Chih-Yuan , Lin Yin-Chia , Chen Huei-Haurng
Published: February 2013

Characteristics of lateral diffused metal–oxide–semiconductor (LDMOS) transistors with gradual junction profile by self-alignment implant through dual thicknesses of screen oxide are presented in this letter. Compared with LDMOS transistors with traditional junction profile, this new device shows improved off-state breakdown voltage, less severe in Kirk effect, and wider electrical safe operating area; without sacrificing device drivability. Technology computer aided design (TCAD) simulation results reveal that this new device has smaller electric field both in off- and on-state bias conditions. Hot-carrier induced degradation of this new device under various stress conditions is also investigated and compared with that of the device with traditional junction profile.
Study Trapped Charge Distribution in P-Channel Silicon–Oxide–Nitride–Oxide–Silicon Memory Device Using Dynamic Programming Scheme
Authors: Li Fu-Hai , Chiu Yung-Yueh , Lee Yen-Hui , Chang Ru-Wei , Yang Bo-Jun , Sun Wein-Town , Lee Eric , Kuo Chao-Wei , Shirota Riichiro
Published: February 2013

In this study, we precisely investigate the charge distribution in SiN layer by dynamic programming of channel hot hole induced hot electron injection (CHHIHE) in p-channel silicon–oxide–nitride–oxide–silicon (SONOS) memory device. In the dynamic programming scheme, gate voltage is increased as a staircase with fixed step amplitude, which can prohibits the injection of holes in SiN layer. Three-dimensional device simulation is calibrated and is compared with the measured programming characteristics. It is found, for the first time, that the hot electron injection point quickly traverses from drain to source side synchronizing to the expansion of charged area in SiN layer. As a result, the injected charges quickly spread over on the almost whole channel area uniformly during a short programming period, which will afford large tolerance against lateral trapped charge diffusion by baking.
Switching Model of TaOx-Based Nonpolar Resistive Random Access Memory
Authors: Tong Xin , Wu Wenjuan , Liu Zhe , Tran Xuan Anh , Yu Hong Yu , Yeo Yee-Chia
Published: February 2013

We report on a novel TaO
x
-based nonpolar resistive random access memory (RRAM) cell design with a Cr/TaO
x
/Al (top-to-bottom) structure. Extensive studies of the switching mechanism of the nonpolar RRAM were performed. The thermal coefficient of resistance of the RRAM in the low-resistance state is observed to adopt different polarities depending on how the preceding set operation was performed. On the basis of this observation, the coexistence of metallic ions and oxygen vacancies in the dominant filament is deduced, and a hybrid filament hypothesis is proposed for the first time to explain the observations. A switching model is provided to explain the microscopic changes in the nonpolar TaO
x
-based RRAM.
Electro-Mechanical Q Factor Control of Photonic Crystal Nanobeam Cavity
Authors: Ohta Ryuichi , Ota Yasutomo , Takagi Hiroyuki , Kumagai Naoto , Tanabe Katsuaki , Ishida Satomi , Iwamoto Satoshi , Arakawa Yasuhiko
Published: February 2013

We design and demonstrate a photonic crystal nanobeam cavity with a Q factor controllable by a micro-electro-mechanical system (MEMS). The cavity is evanescently coupled to an adjacent nanobeam waveguide, and its Q factor is controlled by electro-mechanically adjusting the gap distance between them. We experimentally demonstrate control of the Q factor from 2,250 to 2,750, by applying voltage from 0 to 11 V.
Direct Heteroepitaxial Growth of ZnO over GaN Crystal in Aqueous Solution
Authors: Hamada Takahiro , Ito Akihiro , Nagao Nobuaki , Suzuki Nobuyasu , Fujii Eiji , Tsujimura Ayumu
Published: February 2013

We report on the structural and electrical properties of ZnO films grown on surface-treated GaN/Al2O3substrates by chemical bath deposition. X-ray diffraction analysis indicated that the ZnO films had a single-crystalline wurtzite structure withc-axis orientation. The ZnO film exhibited n-type conduction with a carrier concentration of 6.9 ×1018cm-3, an electron mobility of 41 cm2/(V·s), and a resistivity of 2.2 ×10-2Ω·cm. A low specific contact resistivity of 4.3 ×10-3Ω·cm2was obtained at the ZnO/n-GaN interface. Additionally, the ZnO film exhibited high transparency in the visible and infrared region.
Optical and Electrical Properties of Au- and Ag-Doped ReSe2
Authors: Jian Yu-Ci , Lin Der-Yuh , Wu Jenq-Shinn , Huang Ying-Sheng
Published: February 2013

Single crystals of Au- and Ag-doped ReSe2 (ReSe2:Au and ReSe2:Ag) have been grown by chemical vapor transport (CVT) method using iodine as a transporting agent. The optical properties are studied by absorption and polarized-thermoreflectance (PTR) spectroscopy at different polarization angles in the temperature range between 12 and 300 K. The direct band-edge excitonic transitions (E
1
ex, E
2
ex, E
3
ex, and E

s

ex) have been clearly revealed for the first time in the absorption spectra when the samples are made thin enough. The dominant E
1
ex and E
2
ex excitonic transitions gets strongest as the polarization is parallel and perpendicular to the b-axis, respectively. The parameters that describe the temperature dependence of the excitonic transition energy and the broadening function are extracted and discussed. We have also performed electrical conductivity and Hall measurements at different temperatures to derive the activation energy (∼95 and 50 meV for ReSe2:Au and ReSe2:Ag, respectively).
Analytic Circuit Model of Ballistic Nanowire Metal–Oxide–Semiconductor Field-Effect Transistor for Transient Analysis
Authors: Numata Tatsuhiro , Uno Shigeyasu , Kamakura Yoshinari , Mori Nobuya , Nakazato Kazuo
Published: February 2013

A fully analytic and explicit model of device properties in the ballistic transport in gate-all-around metal–oxide–semiconductor field-effect transistors (MOSFETs) is proposed, which enables circuit simulations. The electrostatic potential distribution in the wire cross section is approximated by a parabolic function. Using the applied potential, the energy levels of electrons are analytically obtained in terms of a single unknown parameter by perturbation theory. Ballistic current is obtained in terms of an unknown parameter using the analytic expression of the electron energy level and the current equation for ballistic transport. We analytically derive the parameter with a one-of-a-kind approximate methodology. With the obtained parameter, the fully analytic and explicit model of device properties such as energy levels, ballistic current, and effective capacitance is derived with satisfactory accuracy compared with the numerical simulation results. Finally, we perform a transient simulation using a circuit simulator, introducing our model to it as a Verilog-A script.
Strikingly high false positivity of surveillance FDG‐PET/CT scanning among patients with diffuse large cell lymphoma in the rituximab era
Authors: Avivi Irit , Zilberlicht Ariel , Dann Eldad J. , Leiba Ronit , Faibish Tal , Rowe Jacob M. , Bar‐Shalom Rachel
Published: February 2013

Predictive value (PV) of surveillance fluorodeoxyglucose positron emission tomography (FDG‐PET) in patients with diffuse large B‐cell lymphoma (DLBCL) treated with chemotherapy‐rituximab (R) versus chemotherapy only, remains unclear. The aim of the current study was to compare the performance of surveillance PET in DLBCL patients receiving CHOP (cyclophosphamide, hydroxydaunorubicin hydrochloride, vincristine, and prednisone) alone versus CHOP‐R. Institutional database was retrospectively searched for adults with newly diagnosed DLBCL, receiving CHOP or CHOP‐R, who achieved complete remission and underwent surveillance PETs. Follow‐up (FU) PET was considered positive for recurrence in case of an uptake unrelated to physiological or known benign process. Results were confirmed by biopsy, imaging and clinical FU. One hundred nineteen patients, 35 receiving CHOP and 84 CHOP‐R, who underwent 422 FU‐PETs, were analyzed. At a median PET‐FU of 3.4 years, 31 patients relapsed (17 vs. 14, respectively; P = 0.02). PET detected all relapses, with no false‐negative studies. Specificity and positive PV (PPV) were significantly lower for patients receiving CHOP‐R vs. CHOP (84% vs. 87%, P = 0.023; 23% vs. 74%, P < 0.0001), reflecting a higher false‐positive (FP) rate in subjects receiving CHOP‐R (77% vs. 26%, P < 0.001). In the latter group, FP‐rate remained persistently high up to 3 years post‐therapy. Multivariate analysis confirmed rituximab to be the most significant predictor for FP‐PET. In conclusion, routine surveillance FDG‐PET is not recommended in DLBCL treated with rituximab; strict criteria identifying patients in whom FU‐PET is beneficial are required. Am. J. Hematol. 88:400–405, 2013. © 2013 Wiley Periodicals, Inc.
Natural weathering studies of biobased thermoplastic starch from agricultural waste/polypropylene blends
Authors: Pang Ming‐Meng , Pun Meng‐Yan , Ishak Zainal Arifin Mohd.
Published: February 2013

Thermoplastic starch (TPS) obtained from agricultural waste was blended with polypropylene (PP) for natural weathering studies. The agricultural waste material was obtained from seeds and tubers with a starch content of approximately 50%. Commercial‐grade TPS and native tapioca‐based TPS were also prepared for comparison. The biobased TPS/PP extruded sheets were exposed to natural weathering for six months and their deterioration in weight, tensile properties, thermal properties, and relative molecular weight were monitored. SEM micrographs revealed the formation of surface cracking and the presence of microorganisms. FTIR spectrum indicated an increase in the carbonyl index over time as a result of the formation of degradation products. TPS/PP blends made from agricultural waste showed a better resistance to natural weathering compared to the other high starch formulation. The higher starch content in the blend system encouraged the rapid degradation process due to the combined effect of UV radiation with oxidation, moisture, temperature, and microbial attack. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
DNAzyme‐Based Probes for Telomerase Detection in Early‐Stage Cancer Diagnosis
Authors: Wang Hui , Donovan Michael J. , Meng Ling , Zhao Zilong , Kim Youngmi , Ye Mao , Tan Weihong
Published: February 2013

Human telomerase is a polymerase enzyme that adds tandem repeats of DNA (TTAGGG) in the telomeric region to the ends of chromosomes. Since telomerase can be detected in immortalized, but not normal, somatic cells, it has been considered a selective target for cancer chemotherapy. Here, we describe a DNAzyme‐based probe to detect the presence of telomerase in cell lysates. Telomerase elongates the primer site on the probe. Subsequent addition of the PbII cofactor activates the DNAzyme, which cleaves the elongated fragment at the RNA site, releasing the probe for repetitive cycling and signal amplification. The cleaved fragment is detected by a reporter molecular beacon. Enzymatic amplification with rapid turnover allows detection of telomerase in the range of 0.1 to 1 μg cell lysate, with a fivefold increase in signal level for cancer cells over normal cells. This probe design can provide a simple, yet rapid and sensitive, measurement of telomerase activity.
ChemInform Abstract: Synthetic Approach for Constructing the 1‐Oxygenated Carbazole Core and Its Application to the Preparation of Natural Alkaloids.
Authors: Bautista Rafael , Jerezano Alberto V. , Tamariz Joaquin
Published: February 2013

Starting with the regioselective condensation of anilines with cyclohexane‐1,2‐diones, a convenient synthesis of 2‐methoxy substituted diarylamines (V) is demonstrated.
Off the Beaten Track: The Use of Secondary Amines in the Ugi Reaction
Authors: Tron Gian Cesare
Published: February 2013

Although the Ugi multicomponent reaction is more than 40 years old, there is still room for its application to the discovery of new multicomponent transformations, even within the constraints of its classic four‐reactant menu (aldehyde, amine, carboxylic acid, and isocyanide). Replacement of a primary amine with a secondary one thus allows the Mumm‐like rearrangement step to be avoided, freezing the reaction course at the stage of an imino‐anhydride intermediate susceptible to alternative nucleophilic trapping. Mainstream post‐transformation strategies can then add a further level of complexity. The potential of this approach to expedite access to molecular scaffolds of biological relevance and to create unprecedented chemical diversity is outlined.
Kimberlite eruptions as triggers for early Cenozoic hyperthermals
Authors: Patterson Michael V. , Francis Don
Published: February 2013

The early Cenozoic experienced at least three short but major hyperthermals associated with disruptions of the global carbon cycle. The largest among those, the Paleocene‐Eocene thermal maximum, was associated with a negative carbon isotopic excursion of ~ 2.5‰ that appears to be best explained by the thermal dissociation of methane hydrates due to an initial period of warming. The cause of the initial warming has been attributed to a massive injection of carbon (CO2 and/or CH4) into the atmosphere; however, the source of the carbon is as yet unknown. The emplacement of a large cluster of kimberlite pipes at ~56 Ma in the Lac de Gras region of northern Canada may have provided the carbon that triggered early warming in the form of exsolved magmatic CO2. Our calculations indicate that the estimated 900–1100 Pg of carbon required for the initial ~3°C of ocean water warming associated with the Paleocene‐Eocene thermal maximum could have been released during the emplacement of a large kimberlite cluster. The coeval ages of two other kimberlite clusters in the Lac de Gras field and two other early Cenozoic hyperthermals indicate that CO2 degassing during kimberlite emplacement is a plausible source of the CO2 responsible for these sudden global warming events.
Weathering geochemistry and Sr‐Nd fingerprints of equatorial upper Nile and Congo muds
Authors: Garzanti Eduardo , Padoan Marta , Setti Massimo , Najman Yani , Peruta Luigi , Villa Igor M.
Published: February 2013

This study investigates processes of sediment generation in equatorial central Africa. An original, complete and integrated mineralogical‐geochemical database on silt‐sized sediments derived from different parent rocks (basalt, granite, gneiss, metapsammite, sandstone) along the East African Rift from 5°S in Tanzania to 5°N in Sudan is presented and used to assess the incidence of diverse factors controlling sediment composition (source‐rock lithology, geomorphology, hydraulic sorting, grain size, recycling), with particular emphasis on chemical weathering.
Laboratory observation of acoustic fluidization in granular fault gouge and implications for dynamic weakening of earthquake faults
Authors: Xia Kaiwen , Huang Sheng , Marone Chris
Published: February 2013

Several lines of evidence, including remote triggering of earthquakes and modulation of seismic tremor by Earth tides, suggest that faults weaken when subject to shaking and dynamic stresses associated with the passage of seismic waves. However, the origin of such dynamic weakening is poorly understood. Here we explore the role of acoustic resonance for dynamic fault weakening using laboratory measurements. Experiments were conducted using a split Hopkinson pressure bar assembly, with dynamic stressing via impact loading. Samples were composed of crushed rock particles from mine tailings with a particle size distribution similar to that found in a natural fault gouge. We used pulse‐shaper techniques and carefully evaluated dynamic stresses recorded at the front and rear of the sample to ensure that dynamic force balance was satisfied. Our experiments document acoustic‐induced fluidization and dramatic dynamic weakening. Frictional strength and elastic modulus of a simulated fault gouge are reduced by a factor of 5–10 via acoustic fluidization. We find a threshold acoustic pressure for fluidization that varies systematically with gouge zone properties. Our observations could help explain dynamic fault weakening and triggering of earthquake fault slip by dynamic stressing.
How do “ghost transients” from past earthquakes affect GPS slip rate estimates on southern California faults?
Authors: Hearn E. H. , Pollitz F. F. , Thatcher W. R. , Onishi C. T.
Published: February 2013

In this study, we investigate the extent to which viscoelastic velocity perturbations (or “ghost transients”) from individual fault segments can affect elastic block model‐based inferences of fault slip rates from GPS velocity fields. We focus on the southern California GPS velocity field, exploring the effects of known, large earthquakes for two end‐member rheological structures. Our approach is to compute, at each GPS site, the velocity perturbation relative to a cycle average for earthquake cycles on particular fault segments. We then correct the SCEC CMM4.0 velocity field for this perturbation and invert the corrected field for fault slip rates. We find that if asthenosphere viscosities are low (3 × 1018 Pa s), the current GPS velocity field is significantly perturbed by viscoelastic earthquake cycle effects associated with the San Andreas Fault segment that last ruptured in 1857 (Mw = 7.9). Correcting the GPS velocity field for this perturbation (or “ghost transient”) adds about 5 mm/a to the SAF slip rate along the Mojave and San Bernardino segments. The GPS velocity perturbations due to large earthquakes on the Garlock Fault (most recently, events in the early 1600s) and the White Wolf Fault (most recently, the Mw = 7.3 1952 Kern County earthquake) are smaller and do not influence block‐model inverted fault slip rates. This suggests that either the large discrepancy between geodetic and geologic slip rates for the Garlock Fault is not due to a ghost transient or that un‐modeled transients from recent Mojave earthquakes may influence the GPS velocity field.
A fractal‐based approach to lake size‐distributions
Authors: Seekell David A. , Pace Michael L. , Tranvik Lars J. , Verpoorter Charles
Published: February 2013

The abundance and size distribution of lakes is critical to assessing the role of lakes in regional and global biogeochemical processes. Lakes are fractal but do not always conform to the power law size‐distribution typically associated with fractal geographical features. Here, we evaluate the fractal geometry of lakes with the goal of explaining apparently inconsistent observations of power law and non–power law lake size‐distributions. The power law size‐distribution is a special case for lakes near the mean elevation. Lakes in flat regions are power law distributed, while lakes in mountainous regions deviate from power law distributions. Empirical analyses of lake size data sets from the Adirondack Mountains in New York and the flat island of Gotland in Sweden support this finding. Our approach provides a unifying framework for lake size‐distributions, indicates that small lakes cannot dominate total lake surface area, and underscores the importance of regional hypsometry in influencing lake size‐distributions.
Hysteretic nonlinear elasticity of Berea sandstone at low‐vibrational strain revealed by dynamic acousto‐elastic testing
Authors: Renaud G. , Rivière J. , Le Bas P.‐Y. , Johnson P.A.
Published: February 2013

Through changes in wave speed of ultrasonic pulses traversing the sample, we measure variations in the elasticity of dry Berea sandstone as a function of the applied low‐frequency (LF) axial strain (varied from 10−7 to 10−5). The approach, termed dynamic acousto‐elasticity, is the dynamic analog of static acousto‐elasticity where the wave speed is measured as a function of the applied static load. Dynamic acousto‐elasticity uses low‐frequency vibrational loading of smaller strain amplitude, typically below 10−4, and it includes inertial effects. At strain amplitudes around 10−6, compression and tension produce a material softening of the material. In contrast, a quasi‐static compression inducing a strain between 10−4 and 10−3 leads to a material stiffening. At 10−5 strain amplitude, elaborate hysteretic signatures of modulus strain are observed. The measurements provide the first direct experimental evidence of hysteretic nonlinear (wave amplitude dependent) elasticity in a sandstone at low dynamic strains.
Evidence of long‐term change in zonal wind in the tropical lower mesosphere: Observations and model simulations
Authors: Venkat Ratnam M. , Kishore Kumar G. , Venkateswara Rao N. , Krishna Murthy B. V. , Laštovička Jan , Qian Liying
Published: February 2013

In recent years, the mesosphere (50 to 85–100 km) has evoked great scientific interest as long‐term changes due to global warming can be clearly captured due to the large perturbation amplitudes at these altitudes. In the present study, zonal wind observations between 70 and 80 km over the Indian region provided by rocketsonde (1977–1991), HRDI/UARS (1991–1999), and MST radar (1995–2010) are used to construct a long‐term data set from 1977 to 2010. Using this unprecedented data set, a decreasing trend of 2 m/s/yr is found, changing from strong eastward winds during the 1970s to weak westward winds in recent years. On the other hand, between 80 and 98 km using medium frequency radar observations during 1993–2009, no perceptible trend is found. Simulations of NCAR TIME‐GCM also showed a similar change in the circulation when CO2 in the atmosphere is doubled, suggesting role of anthropogenic changes in the dynamics of the mesosphere.
Regional climate impacts of a biofuels policy projection
Authors: Anderson Christopher J. , Anex Robert P. , Arritt Raymond W. , Gelder Brian K. , Khanal Sami , Herzmann Daryl E. , Gassman Phillip W.
Published: February 2013

The potential for regional climate change arising from adoption of policies to increase production of biofuel feedstock is explored using a regional climate model. Two simulations are performed using the same atmospheric forcing data for the period 1979–2004, one with present‐day land use and monthly phenology and the other with land use specified from an agro‐economic prediction of energy crop distribution and monthly phenology consistent with this land use change. In Kansas and Oklahoma, where the agro‐economic model predicts 15‐30% conversion to switchgrass, the regional climate model simulates locally lower temperature (especially in spring), slightly higher relative humidity in spring and slightly lower relative humidity in summer, and summer depletion of soil moisture. This shows the potential for climate impacts of biofuel policies and raises the question of whether soil water depletion may limit biomass crop productivity in agricultural areas that are responsive to the policies. We recommend the use of agronomic models to evaluate the possibility that soil moisture depletion could reduce productivity of biomass crops in this region. We conclude, therefore, that agro‐economic and climate models should be used iteratively to examine an ensemble of agricultural land use and climate scenarios, thereby reducing the possibility of unforeseen consequences from rapid changes in agricultural production systems.
Implications of Arctic sea ice changes for North Atlantic deep convection and the meridional overturning circulation in CCSM4‐CMIP5 simulations
Authors: Jahn Alexandra , Holland Marika M.
Published: February 2013

Using CCSM4 climate simulations for 1850–2300 with four different future forcing scenarios, we show that the maximum strength of the Atlantic meridional overturning circulation (MOC) decreases proportionally to the applied CO2 forcing. This weakening of the overturning is caused by a reduction or shut down of North Atlantic (NA) deep convection due to a surface freshening. In the Labrador Sea, the surface freshening is caused by strongly increased liquid freshwater exports from the Arctic, which are largely due to the decrease in the Arctic sea ice cover. In the strongest forcing scenario (RCP8.5), the Arctic becomes summer ice‐free by the end of the 21st century and year‐round ice‐free by the end of the 23rd century. As a result of the associated freshening, all NA deep convection ceases by 2145, which leads to a 72% (18 Sv) decrease of the MOC strength by the end of the simulation in 2300.
Sensitivity of Southern Hemisphere circulation to LGM and 4 × CO2 climates
Authors: Rojas M.
Published: February 2013

This paper investigates the effect of Last Glacial Maximum (LGM) versus high CO2 world boundary condition on the Southern Hemisphere atmospheric circulation, in particular on the strength and latitudinal position of the near surface Southern Westerly Winds (SWW). PMIP2 and PMIP3 experiments, as well as the “abrupt 4 × CO2” simulations from CMIP5, were analyzed. Robust findings include poleward expansion of the Mean Meridional Circulation (MMC) and intensified and poleward‐shifted SWW in the 4 × CO2 simulations (consistent with recent observations and 21st century climate change projections); and for the LGM, stronger and southward shifted northern hemisphere MMC, and weakened southern Hadley cell. However, six of the eight LGM simulations show a decrease in the SWW, the other two models simulate the opposite. A critical difference between the models is strong coupling between sea‐ice extent, surface temperature gradients, SWW, and Ferrel cell in the two models with stronger and poleward‐shifted SWW.
Sensitivity of tropospheric oxidants to biomass burning emissions: implications for radiative forcing
Authors: Mao Jingqiu , Horowitz Larry W. , Naik Vaishali , Fan Songmiao , Liu Junfeng , Fiore Arlene M.
Published: February 2013

Biomass burning is one of the largest sources of trace gases and aerosols to the atmosphere and has profound influence on tropospheric oxidants and radiative forcing. Using a fully coupled chemistry‐climate model (GFDL AM3), we find that co‐emission of trace gases and aerosol from present‐day biomass burning increases the global tropospheric ozone burden by 5.1% and decreases global mean OH by 6.3%. Gas and aerosol emissions combine to increase CH4 lifetime nonlinearly. Heterogeneous processes are shown to contribute partly to the observed lower ΔO3/ΔCO ratios in northern high latitudes versus tropical regions. The radiative forcing from biomass burning is shown to vary nonlinearly with biomass burning strength. At present‐day emission levels, biomass burning produces a net radiative forcing of −0.19 W/m2 (−0.29 from short‐lived species, mostly aerosol direct and indirect effects, +0.10 from CH4‐ and CH4‐induced changes in O3 and stratospheric H2O) but increases emissions to over 5 times present levels would result in a positive net forcing.
FUNCTIONAL ANALYSIS OF VERBAL BEHAVIOR: A BRIEF REVIEW
Authors: Plavnick Joshua B. , Normand Matthew P.
Published: February 2013

A variation of the preintervention functional analysis of problem behavior has recently been extended to identify the function of verbal behavior emitted by children with autism. Recent research suggests that a functional analysis of verbal behavior might be beneficial in evaluating previous instruction and guiding the selection of future educational targets and instructional procedures. The present paper reviews previous literature on the functional analysis of verbal behavior and identifies avenues for future research.
Mechanisms of marine low cloud sensitivity to idealized climate perturbations: A single‐LES exploration extending the CGILS cases
Authors: Bretherton Christopher S. , Blossey Peter N. , Jones Christopher R.
Published: February 2013

Climate change sensitivities of subtropical cloud‐topped marine boundary layers are analyzed using large‐eddy simulation (LES) of three CGILS cases of well‐mixed stratocumulus, cumulus under stratocumulus, and shallow cumulus cloud regimes, respectively. For each case, a steadily forced control simulation on a small horizontally doubly periodic domain is run 10–20 days into quasi‐steady state. The LES is rerun to steady state with forcings perturbed by changes in temperature, free‐tropospheric relative humidity (RH), CO2 concentration, subsidence, inversion stability, and wind speed; cloud responses to combined forcings superpose approximately linearly. For all three cloud regimes and 2× CO2 forcing perturbations estimated from the CMIP3 multimodel mean, the LES predicts positive shortwave cloud feedback, like most CMIP3 global climate models. At both stratocumulus locations, the cloud remains overcast but thins in the warmer, moister, CO2‐enhanced climate, due to the combined effects of an increased lower‐tropospheric vertical humidity gradient and an enhanced free‐tropospheric greenhouse effect that reduces the radiative driving of turbulence. Reduced subsidence due to weakening of tropical overturning circulations partly counteracts these two factors by raising the inversion and allowing the cloud layer to deepen. These compensating mechanisms may explain the large scatter in low cloud feedbacks predicted by climate models. CMIP3‐predicted changes in wind speed, inversion stability, and free‐tropospheric RH have lesser impacts on the cloud thickness. In the shallow cumulus regime, precipitation regulates the simulated boundary‐layer depth and vertical structure. Cloud‐droplet (aerosol) concentration limits the boundary‐layer depth and affects the simulated cloud feedbacks.
Prescription of Antiepileptics and the Risk of Road Traffic Crash
Authors: Orriols Ludivine , Foubert‐Samier Alexandra , Gadegbeku Blandine , Delorme Bernard , Tricotel Aurore , Philip Pierre , Moore Nicholas , Lagarde Emmanuel ,   on behalf of the CESIR Research Group
Published: February 2013

Studies assessing the impact of epilepsy and its medication on the risk of road traffic crashes have shown inconsistent results. The aim in this study was to assess this risk using French databases. Data from three French national databases were extracted and matched: the national health care insurance database, police reports, and the national police database of injurious crashes. Only antiepileptics prescribed predominantly in epilepsy were studied (phenobarbital, phenytoin, ethosuximide, valproic acid, vigabatrin, tiagabin, levitiracetam, zonisamide, and lacosamide). A case–control analysis comparing responsible and non‐responsible drivers and a case–crossover analysis were performed. Drivers (72 685) involved in an injurious crash in France between July 2005 and May 2008, were included. Drivers exposed to prescribed antiepileptic medicines (n = 251) had an increased risk of being responsible for a crash (OR 1.74 [1.29–2.34]). The association was also significant for the most severe epileptic patients (n = 99; OR = 2.20 [1.31–3.69]). Case–crossover analysis found no association between crash risk and treatment prescription. Patients with prescription of antiepileptic drugs should be cautioned about their potential risk of road traffic crash. This risk is however more likely to be related to seizures than to the effect of antiepileptic medicines.