bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production of cryoprotectant extracellular polysaccharide substances (EPS) by the marine psychrophilic bacteriumColwellia psychrerythraeastrain 34H under extreme conditionsThis article is one of a selection of papers in the Special Issue on Polar and Alpine Microbiology.
Authors: Marx Joseph G. , Carpenter Shelly D. , Deming Jody W. 
Published: February 2009

Extracellular polysaccharide substances (EPS) play critical roles in microbial ecology, including the colonization of extreme environments in the ocean, from sea ice to the deep sea. After first developing a sugar-free growth medium, we examined the relative effects of temperature, pressure, and salinity on EPS production (on a per cell basis) by the obligately marine and psychrophilic γ-proteobacterium, Colwellia psychrerythraea strain 34H. Over growth-permissive temperatures of ~10 to –4 °C, EPS production did not change, but from –8 to –14 °C when samples froze, EPS production rose dramatically. Similarly, at growth-permissive hydrostatic pressures of 1–200 atm (1 atm = 101.325 kPa) (at –1 and 8 °C), EPS production was unchanged, but at higher pressures of 400 and 600 atm EPS production rose markedly. In salinity tests at 10‰–100‰ (and –1 and 5 °C), EPS production increased at the freshest salinity tested. Extreme environmental conditions thus appear to stimulate EPS production by this strain. Furthermore, strain 34H recovered best from deep-freezing to –80 °C (not found for Earthly environments) if first supplemented with a preparation of its own EPS, rather than other cryoprotectants like glycerol, suggesting EPS production as both a survival strategy and source of compounds with potentially novel properties for biotechnological and other applications.
ONLINE LEARNING WITH MARKOV SAMPLING
Authors: SMALE STEVE , ZHOU DING-XUAN 
Published: February 2009

This paper attempts to give an extension of learning theory to a setting where the assumption of i.i.d. data is weakened by keeping the independence but abandoning the identical restriction. We hypothesize that a sequence of examples (xt, yt) in X × Y for t = 1, 2, 3,… is drawn from a probability distribution ρt on X × Y. The marginal probabilities on X are supposed to converge to a limit probability on X. Two main examples for this time process are discussed. The first is a stochastic one which in the special case of a finite space X is defined by a stochastic matrix and more generally by a stochastic kernel. The second is determined by an underlying discrete dynamical system on the space X. Our theoretical treatment requires that this dynamics be hyperbolic (or "Axiom A") which still permits a class of chaotic systems (with Sinai–Ruelle–Bowen attractors). Even in the case of a limit Dirac point probability, one needs the measure theory to be defined using Hölder spaces. Many implications of our work remain unexplored. These include, for example, the relation to Hidden Markov Models, as well as Markov Chain Monte Carlo methods. It seems reasonable that further work should consider the push forward of the process from X × Y by some kind of observable function to a data space.
Global C cycle perturbations recorded in marbles: a record of Neoproterozoic Earth history within the Dalradian succession of the Shetland Islands, Scotland
Authors: Prave A.R. , Strachan R.A. , Fallick A.E. 
Published: February 2009

Abstract:

The Shetland Islands in Scotland contain a
c
. 12 km thick, mostly siliciclastic Neoproterozoic succession that experienced deformation and greenschist- to amphibolite-facies metamorphism during the Ordovician–Silurian Caledonian Orogeny. Correlating these rocks with Neoproterozoic successions elsewhere has remained problematic. However, four marble units punctuate the succession; these are, in stratigraphic order, the Weisdale, Whiteness, Girlsta and Laxfirth Limestones, two of which record hallmark C-isotopic excursions diagnostic of Neoproterozoic time. The Whiteness Limestone is lithologically similar to the 635 Ma Marinoan post-glacial cap carbonate sequence and displays a δ
13
C
carbonate
profile in which values decline from a range of 0 to +2‰ to a nadir of −5‰ and then rise towards and oscillate around 0‰. The Girlsta Limestone is a 700–900 m thick marble unit with values of −9‰ to −11‰ and is interpreted as recording the late Neoproterozoic Shuram–Wonoka event. These correlations permit linking the Shetland succession to Neoproterozoic sections elsewhere and also show that rift-related rocks in Shetland post-date the Shuram–Wonoka event (post
c
. 600 Ma–pre
c
. 550 Ma) thereby supporting the concept of a diachronous phase of extensional tectonism, from
c
. 700 Ma in east–central Laurentia to near the close of the Proterozoic in northeastern Laurentia, prior to the opening of the Iapetus Ocean.
Probing the basement of southern Tibet: evidence from crustal xenoliths entrained in a Miocene ultrapotassic dyke
Authors: Chan G.H.-N. , Waters D.J. , Searle M.P. , Aitchison J.C. , Horstwood M.S.A. , Crowley Q. , Lo C.-H. , Chan J.S.-L. 
Published: February 2009

Abstract:

A variety of felsic and mafic granulites and ultramafic rocks occur as xenoliths within a 12.7 Ma ultrapotassic dyke intruding Xigaze flysch immediately to the north of the Yarlung–Tsangpo suture zone in southern Tibet. Garnet–clinopyroxene–plagioclase–quartz thermobarometry on mafic granulite xenoliths gives temperatures of 1130–1330 °C and pressures between 22 and 26 kbar indicating equilibration in the high-pressure and ultrahigh-temperature granulite field and defining a geotherm of
c
. 16 °C km
−1
. Ultramafic xenoliths consist mainly of hornblende and biotite, probably of restitic crustal rather than mantle origin, and attained peak metamorphic conditions of 920–1130 °C and 17–24 kbar, whereas felsic granulites equilibrated at 870–900 °C at an inferred pressure of 17 kbar.
In situ
U–(Th)–Pb laser ablation inductively coupled plasma mass spectrometry dating of zircons shows that protoliths may include Proterozoic basement rocks, Late Cretaceous calc-alkaline tonalites of the Gangdese batholith root and/or remnants of a Neo-Tethyan oceanic arc. Certain zircons from a felsic granulite and an ultramafic xenolith have mean
206
Pb/
238
U ages of 16.8 ± 0.9 Ma and 15.6 ± 0.6 Ma, respectively, and monazites from a micaceous xenolith yielded a mean
208
Pb/
232
Th age of 14.4 ± 0.4 Ma. These results show that the southern Tibet basement reached a thickness of
c
. 80 km by 17–14 Ma at the latest and has remained unchanged until the present day.

Supplementary material:

Mineral analyses used for pressure–temperature estimations and results of
40
Ar/
30
Ar laser single-grain fusion experiments are available at
http://www.geolsoc.org.uk/SUP18325
.
Constraints on
87
Sr/
86
Sr of Late Ediacaran seawater: insight from Siberian high-Sr limestones
Authors: Melezhik V.A. , Pokrovsky B.G. , Fallick A.E. , Kuznetsov A.B. , Bujakaite M.I. 
Published: February 2009

Abstract:

In SE Siberia, carbonate formations with δ
13
C
carb
values ranging between −12‰ and −7‰ (V-PDB) and Sr concentrations of up to 2.5% occupy an area of 40 000 km
2
. Several successions exceed 1000 m in thickness and represent the world's largest known exposures of sedimentary carbonates exhibiting extreme depletion in
13
C. The carbonates were deposited on a carbonate platform evolving from a mixed carbonate–siliciclastic ramp to a carbonate ramp, and then from a peritidal rimmed shelf to a deep-water open shelf. All sequences reveal a facies-independent, upward rise in marine δ
13
C
carb
from −12‰ to −7‰. The trend and magnitude of the values mimic those that are characteristic of the 600–550 Ma Shuram–Wonoka isotope event. A coincident stratigraphic rise in
87
Sr/
86
Sr from 0.70802 to 0.70862 in several sections of limestones, containing 4400 μg g
−1
Sr on average, is considered to be by far the best available constraint on a temporal variation of seawater isotopic composition through the Late Ediacaran. If the greatest temporal rate of change in seawater
87
Sr/
86
Sr observed in the Cenozoic is applied to the Siberian sections, the calculated minimum duration for the Suram–Wonoka event is 10 Ma.

Supplementary material:

XRF and ICP-AES analysis, C, O and Sr isotopic data are available at
http://www.geolsoc.org.uk/SUP18324
.
Kinematics of the Greater Himalayan sequence, Dhaulagiri Himal: implications for the structural framework of central Nepal
Authors: Larson Kyle P. , Godin Laurent 
Published: February 2009

Abstract:

In the Dhaulagiri region of central Nepal quartz-rich specimens sampled from the Greater Himalayan sequence yield well-defined quartz
c
-axis fabrics with a dominant top-to-the-SW sense of shear. These fabrics reflect pervasive crystal-plastic deformation extending more than 8 km structurally below previously mapped locations of the Main Central thrust fault. Quartz
c
-axis fabric opening angles suggest deformation temperatures of
c
. 500 ± 50 °C within the lower portion of the Greater Himalayan sequence and up to
c
. 670 ± 50 °C within the migmatitic upper portion. These temperatures generally plot within error of garnet–biotite temperature estimates for metamorphic assemblages and are interpreted to reflect Tertiary deformation during extrusion of the mid-crust. The quartz
c
-axis data, and a new, detailed tectonostratigraphic map, constrain the position of the Ramgarh thrust in the Dhaulagiri region to be coincident with the Main Central thrust at the base of the pervasively deformed exhumed mid-crustal core. Mean kinematic vorticity numbers (
W
m
) measured in specimens sampled from the lower portion of the Greater Himalayan sequence range between 0.49 and 0.80 (
c
. 66–41% pure shear) with an average value of 0.67 (
c
. 53% pure shear). These data indicate that extrusion of the mid-crust was facilitated by a significant component of pure shear strain.
The significance of the contemporaneous Logoisk impact structure (Belarus) and Afro-Arabian flood volcanism
Authors: Sherlock Sarah C. , Kelley Simon P. , Glazovskaya Liudmila , Peate Ingrid Ukstins 
Published: February 2009

Abstract:

The relationships between meteorite impact craters, flood basalt volcanism and sudden environmental perturbation on Earth have been debated extensively. We present only the second example of contemporaneous meteorite impact and flood basalt volcanism: the 17 km diameter Logoisk impact structure (Belarus) and Afro-Arabian flood volcanism. The new precise
40
Ar/
39
Ar age of 29.71 ± 0.48 Ma for Logoisk is coincident with the acme of flood volcanism. We argue that at least one crater the size of Logoisk is likely to form during the emplacement of a flood volcanic province, and that contemporaneity of impacts and flood volcanism was the norm. The absence of a biotic effect from the combined Logoisk–Afro-Arabian volcanism we attribute to the magnitude of these combined events, which are both significantly smaller than the other known example of the Chicxulub impact event and the Deccan Traps flood volcanism.

Supplementary material:

40
Ar/
39
Ar data are available at
http://www.geolsoc.org.uk/SUP18329
.
Ichnotaxonomy of microbial trace fossils in volcanic glass
Authors: McLoughlin N. , Furnes H. , Banerjee N.R. , Muehlenbachs K. , Staudigel H. 
Published: February 2009

Abstract:

Ancient microbial activity in volcanic glass creates micron-sized cavities that can be regarded as trace fossils. These are common in glassy rims of oceanic pillow lavas and volcanic breccias. Morphologically comparable mineralized traces are also found in (meta)-volcanic glasses from ophiolites and Precambrian greenstone belts. Multiple lines of evidence indicate microbial formation of these borings, although the affinity of the trace maker(s) is poorly constrained. Two broad morphological types have been previously recognized and termed ’granular' and ’tubular' bioalteration textures. Here optical microscopy and SEM observations are used to erect two new ichnogenera:
Granulohyalichnus
igen. nov. and
Tubulohyalichnus
igen. nov. Five ichnospecies are also defined:
Granulohyalichnus vulgaris
isp. nov., a granular species;
Tubulohyalichnus simplus
isp. nov., an unornamented tubular species;
Tubulohyalichnus annularis
isp. nov., an annulated tubular species;
Tubulohyalichnus spiralis
isp. nov., a helicoidal tubular species;
Tubulohyalichnus stipes
isp. nov., a branched tubular species. This systematic taxonomy is advanced to allow reliable comparisons to be made between new and existing reports of these microbial borings. Moreover, the adoption of a taxonomic framework will aid the development of these ichnofossils as palaeoenvironmental indicators and tracers of microbial evolution.
Ionizing Radiation Up-regulates Telomerase Activity in Cancer Cell Lines by Post-translational Mechanism via Ras/Phosphatidylinositol 3-Kinase/Akt Pathway
Authors: Ram Ron , Uziel Orit , Eldan Orit , Fenig Eyal , Beery Einat , Lichtenberg Shelly , Nordenberg Yardena , Lahav Meir 
Published: February 2009

Abstract
Purpose: Telomerase is considered currently as a hallmark of cancer, and its inhibition is expected to become an important anticancer modality. In contrast to abundant data concerning the effect of cytotoxic drugs on telomerase activity (TA), there is scant information on the effect of radiation on telomerase. The mechanism of telomerase regulation by irradiation has never been evaluated in detail. In the present study, we investigated the effect of radiation on TA and its regulation in cancer cells.
Experimental Design: The effect of various radiation doses on TA in several malignant and nonmalignant cell lines was evaluated. All malignant cells exhibited similar telomerase response to radiation and its regulation was assessed at transcriptional and post-translational levels in K562 cells. Next step was the evaluation of the upstream signaling pathways leading to changes in TA using kinetics and specific inhibitors.
Results: Radiation up-regulated TA in dose-dependent manner only in cancer cells. Telomerase was activated by phosphorylation by Akt and by cytoplasmic-nuclear shift. Transcriptional processes were not involved in TA. This telomerase regulation is mediated by Ras/phosphatidylinositol 3-kinase/Akt pathway. The canonical membrane effectors of irradiation (epidermal growth factor receptor, insulin-like growth factor-I receptor, and Ca2+ influx) were not involved in this process.
Conclusions: Radiation up-regulates telomerase activity specifically in cancer cells. This study adds to accumulating evidence pointing to post-translational level as important mode of telomerase regulation. Telomerase activation due to radiation may be detrimental in treatment of cancer. Data described in this study may add to future interventions aiming at inhibition of telomerase activation during irradiation.
A Phase I Study of Samarium Lexidronam/Bortezomib Combination Therapy for the Treatment of Relapsed or Refractory Multiple Myeloma
Authors: Berenson James R. , Yellin Ori , Patel Ravi , Duvivier Herb , Nassir Youram , Mapes Russell , Abaya Christina DiLauro , Swift Regina A. 
Published: February 2009

Abstract
Purpose: This open-label, phase I dose-escalation study assessed the safety, tolerability, and initial efficacy of Samariam 153 (153Sm)-lexidronam/bortezomib combination therapy for patients with relapsed/refractory multiple myeloma.
Experimental Design: Patients were enrolled in six cohorts and given bortezomib (1.0 or 1.3 mg/m2) on days 1, 4, 8, and 11 and 153Sm-lexidronam (0.25, 0.5, or 1.0 mCi/kg) on day 3 of a 56-day cycle (maximum of four cycles). The primary endpoints were safety and tolerability of the 153Sm-lexidronam/bortezomib regimen.
Results: Twenty-four patients were enrolled. Median values for age, time since diagnosis, and number of prior treatments were 63 years, 29 months, and three regimens, respectively. The most common toxicities were hematologic; during the first cycle, median neutrophil and platelet nadirs were 1,000/mm3 and 98,500/mm3, respectively, and observed generally 3 to 4 weeks post-treatment. The incidences of grade 4 neutropenia and thrombocytopenia were 12.5% and 8.3%, respectively, during treatment cycle 1. Dose-limiting toxicity, reached in cohort 6 as a result of hematologic toxicity, defined the maximum tolerated dose as 0.5 mCi/kg 153Sm-lexidronam in combination with 1.3 mg/m2 bortezomib. The maximum tolerated dose for 153Sm-lexidronam in combination with the 1.0 mg/m2 bortezomib was not reached. No nonhematologic dose-limiting toxicities were observed; both the incidence and the severity of peripheral neuropathy were low. Responses occurred in 5 (21%) patients, including 3 (12.5%) complete and 2 (8.3%) minimal responses.
Conclusions: Bortezomib combined with 153Sm-lexidronam appears to be a well-tolerated regimen, which showed clinical activity in this phase I trial for patients with relapsed or refractory multiple myeloma.
Mechanism of Purinergic Activation of Endothelial Nitric Oxide Synthase in Endothelial Cells
Authors: da Silva Cleide Gonçalves , Specht Anke , Wegiel Barbara , Ferran Christiane , Kaczmarek Elzbieta 
Published: February 2009

Background—Decreased endothelial nitric oxide (NO) synthase (eNOS) activity and NO production are critical contributors to the endothelial dysfunction and vascular complications observed in many diseases, including diabetes mellitus. Extracellular nucleotides activate eNOS and increase NO generation; however, the mechanism of this observation is not fully clarified.Methods and Results—To elucidate the signaling pathway(s) leading to nucleotide-mediated eNOS phosphorylation at Ser-1177, human umbilical vein endothelial cells were treated with several nucleotides, including ATP, UTP, and ADP, in the presence or absence of selective inhibitors. These experiments identified P2Y1, P2Y2, and possibly P2Y4 as the purinergic receptors involved in eNOS phosphorylation and demonstrated that this process was adenosine independent. Nucleotide-induced eNOS phosphorylation and activity were inhibited by BAPTA-AM (an intracellular free calcium chelator), rottlerin (a protein kinase Cδ inhibitor), and protein kinase Cδ siRNA. In contrast, blockade of AMP-activated protein kinase, calcium/calmodulin-dependent kinase II, calcium/calmodulin-dependent kinase kinase, serine/threonine protein kinase B, protein kinase A, extracellular signal-regulated kinase 1/2, and p38 mitogen-activated protein kinase did not affect nucleotide-mediated eNOS phosphorylation.Conclusions—The present study indicates that extracellular nucleotide–mediated eNOS phosphorylation is calcium and protein kinase Cδ dependent. This newly identified signaling pathway opens new therapeutic avenues for the treatment of endothelial dysfunction.
Arthroscopic versus Open Acromioplasty
Authors: Davis A. David , Kakar Sanjeev , Moros Chris , Krall Kaye Elizabeth , Schepsis Anthony A. , Voloshin Ilya 
Published: February 2009

Background To address persisting controversy in the literature concerning the efficacy of arthroscopic compared to open acromioplasty, a meta-analysis was performed to evaluate the treatment effect after both approaches. Hypothesis The final clinical outcomes will be the same after both open and arthroscopic acromioplasty. However, the arthroscopic technique results in faster recovery and less postoperative morbidity as reflected by faster return to work and decreased hospital stays. Study Design Meta-analysis; Level of evidence, 3. Methods We performed our search of published English language literature using PubMed. We also searched the proceedings from 4 major orthopaedic meetings convened from 2000 to 2007. Furthermore, the reference sections of all relevant articles were reviewed for pertinent studies and presentations. Nine studies met the inclusion criteria that directly compared arthroscopic versus open acromioplasty with minimum follow-up of 1 year. The analysis focused on 1-year clinical outcome and included comparison of the objective 100-point score, hospital stay, time until return to work, operative time, and complications. Results No significant differences were found in clinical outcomes or complications for the 2 groups. However, open acromioplasty was associated with longer hospital stays (2.3 days, P = .05) and a greater length in time until return to work (65.1 days) compared with the arthroscopic technique (48.6 days) (P < .05). Conclusion Arthroscopic and open acromioplasty have equivalent ultimate clinical outcomes, operative times, and low complication rates. However, arthroscopic acromioplasty results in faster return to work and fewer hospital inpatient days compared with the open technique.
A Prospective Comparison of 3 Hamstring ACL Fixation Devices—Rigidfix, BioScrew, and Intrafix—Randomized into 4 Groups with 2 Years of Follow-Up
Authors: Harilainen Arsi , Sandelin Jerker 
Published: February 2009

Background New devices for graft fixation in anterior cruciate ligament reconstruction are released to clinical use without clinical follow-up data. Hypothesis There is similar clinical outcome after either cross-pin or absorbable interference screw fixation in anterior cruciate ligament reconstruction with hamstring tendons. Study Design Randomized controlled clinical trial; Level of evidence, 1. Methods A total of 120 patients were randomized into 4 different groups (30 each) for anterior cruciate ligament reconstruction with hamstring tendons: femoral Rigidfix cross-pin and Intrafix tibial expansion sheath with a tapered expansion screw; Rigidfix femoral and BioScrew interference screw tibial fixation, BioScrew femoral and Intrafix tibial fixation; or BioScrew fixation into both tunnels. The evaluation methods were clinical examination, knee scores, and instrumented laxity measurements. Results Ten patients were completely lost to follow-up and 3 revisions were done before the 2-year follow-up, leaving 107 of 120 (89%) patients for analysis. No statistically significant differences between the groups were seen 2 years postoperatively, and all but 2 patients in the Rigidfix/Intrafix and Rigidfix/BioScrew groups, respectively, were classified into International Knee Documentation Committee A or B categories. A revision reconstruction was performed before the 2-year follow-up in 2 cases after a high-energy injury caused a rerupture (1 in Rigidfix/Intrafix and 1 in BioScrew/BioScrew groups). In addition, there were 4 nontraumatic failures revised before the 2-year follow-up (2 in Rigidfix/Intrafix and 1 each in Rigidfix/BioScrew and BioScrew/BioScrew). Conclusion There were no statistically or clinically relevant differences in the results 2 years postoperatively, and all 4 techniques improved patient performance.