bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unique fluorophores in the dimeric archaeal histones hMfB and hPyA1 reveal the impact of nonnative structure in a monomeric kinetic intermediate
Authors: Stump Matthew R. , Gloss Lisa M. 
Published: December 2007

AbstractHomodimeric archaeal histones and heterodimeric eukaryotic histones share a conserved structure but fold through different kinetic mechanisms, with a correlation between faster folding/association rates and the population of kinetic intermediates. Wild‐type hMfB (from Methanothermus fervidus) has no intrinsic fluorophores; Met35, which is Tyr in hyperthermophilic archaeal histones such as hPyA1 (from Pyrococcus strain GB‐3A), was mutated to Tyr and Trp. Two Tyr‐to‐Trp mutants of hPyA1 were also characterized. All fluorophores were introduced into the long, central α‐helix of the histone fold. Far‐UV circular dichroism (CD) indicated that the fluorophores did not significantly alter the helical content of the histones. The equilibrium unfolding transitions of the histone variants were two‐state, reversible processes, with ΔG°(H2O) values within 1 kcal/mol of the wild‐type dimers. The hPyA1 Trp variants fold by two‐state kinetic mechanisms like wild‐type hPyA1, but with increased folding and unfolding rates, suggesting that the mutated residues (Tyr‐32 and Tyr‐36) contribute to transition state structure. Like wild‐type hMfB, M35Y and M35W hMfB fold by a three‐state mechanism, with a stopped‐flow CD burst‐phase monomeric intermediate. The M35 mutants populate monomeric intermediates with increased secondary structure and stability but exhibit decreased folding rates; this suggests that nonnative interactions occur from burial of the hydrophobic Tyr and Trp residues in this kinetic intermediate. These results implicate the long central helix as a key component of the structure in the kinetic monomeric intermediates of hMfB as well as the dimerization transition state in the folding of hPyA1.
The Endoscopic Detection and Treatment of Vascular Ectasia in the Gastrointestinal Tract —A One Year Experience at Karolinska Hospital—
Authors: SHIRAI Masato , JARAMILLO Edgar , BEFRITS Ragnar , JONAS Eduard , LJUNG Tryggve , SLEZAK Premysl 
Published: December 2007

Abstract: Vascular ectasia of the upper and lower gastrointestinal tract (GIT) is occasionally seen at diagnostic endoscopy. The therapeutic relevance of these lesions are not always immediately clear. The aim of this study was to review a single institution's experience in the endoscopic diagnosis and treatment of GIT vascular ectasia. In order to identify and determine the characteristics and clinical course of patients with vascular ectasia, records of all adult patients undergoing upper or lower GIT endoscopy between September 1996 and August 1997 were reviewed.During the study period 2547 gastroscopies and 1759 colonoscopies were performed. Eighteen patients (0.7%) were diagnosed with vascular ectasia of the upper GIT and 23 patients (1.6%) the lower GIT. Mean age was 72.7 years and the majority of patients were male. A large percentage of patients had coexisting systemic disease. Anemia without overt GIT bleeding was the presenting clinical sign in 67% of upper GIT and 43% of lower GIT vascular ectasia. Fourteen patients received endoscopic treatment for upper GIT and 18 for lower GIT vascular ectasia. Endoscopic treatment was effective in 12 (86%) and 14 patients (78%) with upper and lower GIT vascular ectasia, respectively. Follow‐up ranged from 2 to 12 months. There was only one death in each group, both due to systemic diseases unrelated to vascular ectasia. Vascular ectasia of the GIT is a not infequent cause of upper and lower gastrointestinal bleeding and might be occult. Patients are usually elderly with coexisting systemic disease. Multi‐modality endoscopic management is the first line of treatment for this condition and seems both effective and safe.
A Case of Gastric Lipoma Removed by Endoscopic Polypectomy
Authors: YAMAMOTO Takatsugu , KUYAMA Yasushi , OBARA Masayuki , TANAKA Hideyo , SANAKA Masaki , ISHII Taro , TAMURA Mizue , YAMANAKA Masami , IMAMURA Tetsuo 
Published: December 2007

Abstract: A rare case of gastric lipoma removed by endoscopic polypectomy is presented herein. A 64‐year‐old female was found to have a polypoid lesion in the stomach on periodic X‐ray examination. Endoscopy revealed a submucosal tumor located on the posterior wall of the antrum. Endoscopic ultrasonography demonstrated a homogeneous, hyperechoic mass continuous with the submucosal layer, suggesting a lipoma. Because the likelihood of the tumor ultimately causing obstruction or prolapse into the duodenum was high, endoscopic polypectomy was performed. There were no complications. The histological examination revealed a mass of mature adipose tissue underneath the normal mucosa, which was consistent with the diagnosis made prior to polypectomy.The preferred treatment for gastric lipomas to date has been surgical excision, because the diagnosis is difficult to make prior to treatment. In the literature, only 17 cases undergoing endoscopic treatment for gastric lipomas have been reported. Endoscopic ultrasonography and computed tomography apparently facilitate preoperative diagnosis of lipomas.
Regression of Gastroduodenal Mucosa‐Associated Lymphoid Tissue Lymphoma after Eradication of Helicobacter pylori: A Case Report
Authors: KAJIMURA Masayoshi , NAKAGAWARA Masanori , YOSHIDA Ken‐ichi , KATAOKA Hideki , SHIRAI Naohito , SHNIZU Shin‐ichi , KOBAYASHI Hiroshi , SUCHI Taizan 
Published: December 2007

Abstract:Increasing evidence suggests that eradication therapy of Helicobacter pylori (H. pylori) may be an effective treatment for gastric lymphoma of mucosa‐associated lymphoid tissue (MALToma), but it remains unclear whether a similar therapeutic effect may be obtained for MALToma at other sites. We describe here a case of regression of gastroduodenal MALToma after eradication therapy for H. pylori. A 39‐year‐old man underwent gastroscopy at a routine check‐up, which demonstrated protruding lesions like a raised erosion in the antrum and multiple whitish granular lesions in the fornix. Simultaneously, multiple coarse nodular lesions were also found in the duodenal bulb. Forceps biopsy specimens obtained from both the stomach and bulb showed infiltration of small‐ to medium‐sized lymphocytes with cleaved nuclei, centrocyte‐like cells, together with atypical large lymphoid cells into the glandular lesion, and the rearrangement of immunoglobulin was positive, thereby allowing diagnosis of low grade MALToma with large cell transformation. H. pylori was positive in the stomach, while the presence of H, pylori was not detected microscopically in the bulb, although ectopic gastric mucosa was identified in the bulb. Regression of multiple coarse or granular lesions in both the stomach and bulb were observed three months after eradication of H. pylori. Thereafter the disappearance of MALToma was verified histologically a further six months later. There was no recurrence of MALToma detected over a two‐year follow‐up period. These findings suggest that eradication of H. pylori could be a treatment of first choice for MALToma occurring in the gastrointestinal tract outside the stomach.
A Case of Hemophilia B with Esophageal Varices Treated by Sclerotherapy with Factor‐IX Complex
Authors: KAYASHIMA Shinsuke , MURASHIMA Naoya , TAKEI Kazuo , NAKAYAMA Satoshi , MATSUOKA Masaki , YOSHIDA Yukiya , HAYAKAWA Kazuo , FUKUCHI Sohtarou , FUJIOKA Takahiro , OHBA Ken‐ichi 
Published: December 2007

Abstract:A 64‐year‐old man with hemophilia B and HCV‐positive chronic hepatitis who had been followed at our hospital presented with hematemesis. Gastrointestinal fiber‐scopy (GIF) demonstrated a small active gastric ulcer (Az stage) at the pyloric ring and esophageal varices (F1 Lm Cw RC(+)). He was admitted and the esophageal varices were safely and successfully treated by sclerotheapy. Sclerotherapy was performed by in‐traluminal injection of 4 mL 5% ethanolamine oleate with sufficient supplementation of factor‐lX complex (PPSB ‐HT) for four days to a total amount of 24,000 U. The patient was followed with GIF and endoscopic ultrasonography. Sclerotherapy proved effective after six months. We report a rare case of hemophilia B with esophageal varices successfully treated by sclerotherapy.
A Device for Simultaneous Application of Sclerotherapy and Endoscopic Ligation for Management of Esophageal Varices
Authors: MURASHIMA Naoya , KOBAYASHI Masahiro , KOBAYASHI Mizuho , TSUBOTA Akihito , SUZUKI Yoshiyuki , SAITOH Satoshi , ARASE Yasuji , CHAYAMA Kazuaki , IKEDA Kenji , KUMADA Hiromitsu 
Published: December 2007

Abstract:A device developed for simultaneous application of sclerotherapy and endoscopic variceal ligation to treat esophageal varices is described. This device took less than 14 sec to attach to the endoscope, compared to 71 sec using the conventional device. The success rate of intravariceal injection using a 3‐cm or 4‐cm long hemostatic balloon or a conventional balloon was not significantly different. This device had the added advantage that simultaneous sclerotherapy and ligation were possible without changing the endoscope.
Timing of Cenozoic extensional tectonics in west Turkey
Authors: SEYITOǴLU G. , SCOTT B. C. , RUNDLE C. C. 
Published: December 2007

The timing of the transition from compressional to extensional tectonics in the late Cenozoic evolution of west Turkey has been constrained by K-Ar geochronology from acidic volcanic rocks and tourmaline leucogranite dykes in the central and east margin respectively of the Gördes basin.
Dacites and rhyolites in the centre of the Gördes Neogene sedimentary basin cut both the basement ophiolites of the Izmir-Ankara suture zone and the Neogene sediments. On the basin’s eastern margin the leucogranites cut metamorphic basement along a major NE-SW-trending normal fault that controls the regional structure of the basin. Pebbles of these leucogranites occur in adjacent Neogene turfites and conglomerates.
K-Ar dates on biotites from the central volcanic rocks vary from 18.4 ± 0.8 Ma to 16.3 + 0.5 Ma (early Miocene) whilst muscovite from a leucogranite on the eastern margin of the basin provides ages of 24.2 ± 0.8 Ma and 21.1 ± 1.1 Ma (latest Oligocene to early Miocene).
Geochronological data and field relationships demonstrate that the earlier compressional regime had been replaced by extensional tectonics by latest Oligocene-early Miocene.
Background to the Cambrian Explosion
Authors: BRASIER M. D. 
Published: December 2007

This thematic set brings together invited papers given at the Lyell Meeting on 14 February 1991. Despite the Siberian weather, over 60 scientists descended on Burlington House from 12 different countries to attend this meeting, which brought together a wide range of specialists. A major aim of the meeting was to discuss the background to the ‘Cambrian Explosion’ by focussing on various aspects of ‘Geological and biological changes across the Proterozoic-Phanerozoic transition’.
This interval (Fig. 1) marked a major turning point in the geological record, during which the major invertebrate groups appeared. Rapid evolutionary diversification (Fig. 2) is clear from data presented in the following papers. Decline in the abundance and diversity of the soft-bodied Ediacara fauna during the Kotlinian Crisis was followed by an adaptive radiation that included trace fossils, acritarch phytoplankton and a variety of early skeletal fossils. The rise and subsequent fall of the early Cambrian biota is most dramatically picked out by the history of archaeocyathan sponges (Fig. 2) which largely became extinct during the Toyonian Crisis.

No biostratigraphical framework existed for this remote part of the scale prior to 1960.
J. W. Cowie
gives the background to the last two decades of steady progress by members of IGCP Project 29 on the Precambrian-Cambrian boundary, leading up to a vote on the boundary stratotypes at about the time of the Lyell Meeting. In the interval between the meeting and going to press, a majority vote has favoured placing the Precambrian-Cambrian boundary at a point marked by
Burgess Shale-type faunas in the context of the ‘Cambrian explosion’: a review
Authors: CONWAY MORRIS S. 
Published: December 2007

Burgess Shale-type faunas are now known from almost 40 lower and middle Cambrian localities, although those from British Columbia (Canada), Yunnan (China) and Peary Land (Greenland) are of paramount significance. The diverse faunas are dominated by animals with an otherwise negligible fossilization potential, and their stratigraphical position makes them of unique importance in documenting the major adaptive radiations at this time (‘Cambrian explosion’).
Important features of these faunas include the presence of taxa surviving from the late Precambrian Ediacaran faunas, the discovery of articulated material that throws new light on scleritome organization in various Cambrian skeletal taxa, and the significance of the degree of anatomical disparity among Cambrian animals. In addition, these soft-bodied faunas offer some hope of reconciling soft-part data with trace fossil occurrences. New discoveries of Burgess Shale-type faunas are inevitable, and such finds will continue to enhance our under­standing of early animal evolution.
Passive continental margin subsidence
Authors: BARR D. 
Published: December 2007

The papers in the following thematic set arise from the 1991 William Smith Lecture Meeting of the Geological Society, convened by J. M. Cubitt and held at Burlington House on 3 April 1991.

The purpose of this meeting was to review our current understanding of passive margin subsidence. To this end an international cast of speakers was invited to a meeting centred on the William Smith Lecture by A.B. Watts of Oxford University. Four of the papers delivered are published here.
Passive margins form just over half of the present-day continental margin system and, although like the world's oceans all are relatively young (Mesozoic-Tertiary), former passive margins of Palaeozoic and Precambrian age are preserved in orogenic belts and plate interiors. It is now generally accepted that passive margin subsidence is a direct consequence of litho-spheric thinning, most of which took place prior to final separation of the continents and emplacement of an oceanic spreading centre. Intracontinental rifts that failed to develop oceanic crust are geodynamically very similar to passive margins, and in recent years lessons learned in one environment have been successfully applied in the other.
In both cases, subsidence is isostatically driven and results from thinning of the continental crust and its replacement by higher density mantle. Because extension and thinning tends to involve the whole lithosphere (125 km or so in thickness), and not just the top 30 km or so of continental crust, higher density lithospheric mantle is displaced by lower density astheno-sphere during stretching, partially canceling
A pre-caldera plateau-andesite field in the Borrowdale Volcanic Group of the English Lake District
Authors: PETTERSON M. G. , BEDDOE-STEPHENS B. , MILLWARD D. , JOHNSON E. W. 
Published: December 2007

The 6 km thick Ordovician Borrowdale Volcanic Group is readily divisible into a lower 2.2–2.7 km thick predominantly pre-caldera succession dominated by basalt, andesite and dacite sheets, and an upper succession of caldera-related ignimbrites and volcaniclastic sedimentary rocks of
c.
3 km thickness. The lower Borrowdale Volcanic Group rocks, here included within a single lithostratigraphical unit, the Birker Fell Formation, affords a well-exposed section through a pre-caldera sequence.

The Birker Fell Formation is dominated by andesites which comprise 60% of the stratigraphy. Thin sequences of reworked volcanic detritus are commonly interbedded with the andesites; locally there are thicker units of volcaniclastic sedimentary rocks. Interpretation of the stratigraphy and eruptive history of the formation has been aided by the recognition of some distinctive lithological units including: (1) a 200-600 m thick sequence of weakly parallel-bedded basaltic tuffs resting on the pre-volcanic basement, (2) a 200-600 m sequence of single flow unit aa basalts, (3) dacite flows and ignimbrites up to > 1100 m thick in the middle and upper parts of the formation and (4) aphyric to pyroxene-phyric, simple and compound flows of basalt, 50-400 m thick, locally present in the uppermost parts.
Analysis of the facies comprising the Birker Fell Formation indicates that it was emplaced as a sub-aerial, plateau-andesite sequence, formed by the coalescence of products erupted from a number of centres or fissures in an extensional, subsiding volcano-tectonic rift zone. Volcano-tectonic faulting and eruption of thick ignimbrites locally influenced development of this field.
Chemical cyclicity and correlation of Lower Lias mudstones using gamma ray logs, Yorkshire, UK
Authors: VAN BUCHEM F. S. P. , MELNYK D. H. , McCAVE I. N. 
Published: December 2007

Natural gamma-ray spectrometry on coastal sections from Redcar and Robin Hood's Bay permits the radioactive characterization of five different mudstone units and the construction of an outcrop gamma-ray log for the Lower Lias. Correlation of these five units with their equivalents in the gamma-ray log of the Felixkirk Borehole, located 40 km to the west, has been established. Statistical comparison of tie points in the composite coastal section shows there to be a stratigraphic gap of 10 m between the two localities relative to the continuous section in the Felixkirk Borehole.
The distribution of Th (ppm), K (%) and U (ppm) are generally highly correlated with the total radioactivity. However, anomalies do occur: a peak in the Th/K ratio can be related to an iron-oolitic horizon marking a condensed sequence in the early/mid-Sinemurian; a sharp fall in the Th/K ratio followed by high U values coincides with the early-Pliensbachian transgression. Comparison with mineralogical (clays) and chemical (Si/Al and Al/K ratio, V, Total Organic Carbon) profiles of the same section allows for an evaluation of the significance of radioactive element distribution in terms of grainsize, run-off and oxygenation indicators.
A spline curve fitted through the total radioactivity data emphasizes low frequency cyclicity (wavelengths of between 10 and 30 m) in the outcrop section. These cycles appear to be correlatable with cycles of comparable wavelengths in the low-pass filtered gamma-ray log of the Felixkirk Borehole. Sedimentological evidence confirmed high radioactivity peaks correspond to transgressive phases. The gamma-ray signal of the Felixkirk borehole has also been analysed for high frequency cyclicity. With an overall rate of accumulation of about 13m/Ma variation in the Milankovitch band is marked by units 5 m or less in thickness. Evidence for eccentricity, obliquity and precession cycles has been found both in borehole and in outcrop. A typical shift from lower to higher frequencies occurs consistently in transgressive phases, and is related to increased sedimentation rates.
Organisms and sediments: relationships and applications
Authors: GOLDRING R. , POLLARD J. E. 
Published: December 2007

The sixth Lyell meeting of the Geological Society was held on 13 February 1992. Major themes included advances in the study of trace fossils with emphasis on ichnofabrics, and the use of skeletal accumulations (shell and bone beds), both in elucidating environmental change, and in sequence stratigraphy. Of the 12 papers read at the meeting, seven are published in this thematic set.

The papers presented cover topics which Lyell did not himself discuss at any length, with the exception of his classic study on the Temple at Puzzuoli. Nevertheless the theme of the meeting was aptly expressed by him: ‘Arrangements of fossils in strata: Each stratum in fact however far it may now lie beneath the surface was once in the state of shingle, loose sand or soft mud at the bottom of the sea, in which shells and other bodies easily became enveloped. By attending to the nature of these remains we are often enabled to determine whether deposition was slow or rapid, whether it took place in a deep or shallow sea, near the shore or far from land, and whether the water was salt, brackish or fresh’ (Elements of Geology, Chapter 3).
As well as honouring Lyell it was befitting to remember Robert W. Frey (University of Georgia, Athens) who died on 1 January 1992 following a long fight against cancer. Much of his considerable research output was directly in the fields covered at the meeting. Over the past 20 years he pioneered the study of animal-sediment
Volcanically influenced calcareous palaeosols from the Miocene Kiahera Formation, Rusinga Island, Kenya
Authors: BESTLAND E. A. , RETALLACK G. J. 
Published: December 2007

The Miocene Kiahera Formation at its type locality on Rusinga Island in the Kenyan part of Lake Victoria consists of a sequence of alluvial sedimentary and pyroclastic strata and calcareous palaeosols. The 80 m thick formation was formed by braidplain aggradation and pyroclastic airfall in response to volcanism from the nearby Kisingiri volcano.
Numerous fining-upward sequences approximately 5 m to 15 m thick make up the bulk of the Kiahera Formation. A complete sequence contains sandy and conglomeratic beds at the base which fine upward to sandy siltstones, calcareous palaeosols and airfall tuffs. The fining-upward sequences may have been produced by aggradation during phases of volcanic eruption. During major eruptive episodes, scoriaceous nephelinite detritus flooded the alluvial system to create the lower, coarse-grained beds. As eruptive activity waned, airfall ash and overbank flood deposits accumulated on the landscape forming the upper, fine-grained beds of the sequence. Calcareous soils formed on these highly alkaline ashes between large ash fall events.

The calcareous palaeosols are grouped broadly into two main types: tuffaceous clayey Inceptisols with distinct Ck horizons (Chido palaeosols) and sandy Inceptisols consisting of nephelinitic rock fragments and subordinate amounts of tuff (Okoto palaeosols). Both types show only weak to moderate soil development interpreted to be a result of episodic rejuvenation by fresh airfall ash and flood deposits. Comparison of depth of the calcareous subsurface horizon from these palaeosols with those in calcareous modern soils from the Serengeti Plain that also developed on alkaline volcanic ash allow for rainfall estimates of between 550 mm a
−1
to 750 mm a
−1
for the Kiahera palaeosols. This together with root traces, soil structure, and major element chemistry of the two palaeosol types are evidence of a landscape with sandy, stream-side woodland soils (Okoto palaeosols) and clayey, floodplain grassy woodland soils (Chido palaeosols).