bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthese und Charakterisierung von Methyldialkoxogallanen MeGa(OR)2 (R = Et, nBu)
Authors: Chamazi Navabeeh Nami , Heravi Majid M. , Neumüller Bernhard
Published: April 2007

Synthesis and Characterization of Methyldialkoxogallanes MeGa(OR)2(R = Et, nBu)

GaMe3 reacts with ROH (R = Et, nBu) to give the methyldialkoxogallanes MeGa(OR)2 [R = Et (1), nBu (2)] under evolution of methane in boiling toluene. 1 and 2 were characterized by NMR and IR spectroscopy as well as by X‐ray analyses. According to the structural investigations both compounds form centrosymmetrical dimers which are connected to infinite chains along [100] (1) or [001] (2).
Synthese und Struktur der Cluster [Cu50Se24(S‐thiaz)2(dppm)10] und [Cu48Se24(S‐thiazH)2(dppm)10]
Authors: Fuhr Olaf , Fernandez‐Recio Lucia , Castiñeiras Alfonso , Fenske Dieter
Published: April 2007

Synthesis and Structure of the Clusters [Cu50Se24(S‐thiaz)2(dppm)10] and [Cu48Se24(S‐thiazH)2(dppm)10]

The reaction of copper(I) acetate with bis(diphenylphosphanyl)methane (dppm), 2‐mercaptothiazoline (S‐thiazH) and Se(SiMe3)2 in DME leads to the formation of [Cu50Se24(S‐thiaz)2(dppm)10] (1). In some rare cases additionally another cluster, [Cu48Se24(S‐thiazH)2(dppm)10] (2), is formed. Both clusters have nearly equal molecular structures; they only differ in the area, where the 2‐mercaptothiazoline ligands are located. In their copper selenium core both show structural features that are typical for the low temperature phase of binary Cu2Se.
Synthese und Kristallstrukturen von [p‐Me3NC6H4HgOC(O)Me][MeOSO3] und [(p‐Me3NC6H4)2Hg][HgI4]
Authors: Kuhn Norbert , Abu‐Salem Qutaiba , Maichle‐Mößmer Cäcilia , Steimann Manfred
Published: April 2007

Syntheses and Crystal Structures of [p‐Me3NC6H4HgOC(O)Me][MeOSO3] and [(p‐Me3NC6H4)2Hg][HgI4]

The carbene complexes [p‐Me3NC6H4HgOC(O)CH3][MeOSO3] (5) and [(p‐Me3NC6H4)2Hg][HgI4] (7) are obtained by alkylation of Me2NC6H4HgOC(O)Me (4) with Me2SO4 or MeI. The crystal structures of 5 and 7 reveal the expected presence of Hg‐C single bonds in both complexes.
Preparation and Characterization of Boron Chelates with Pyridoxine. The Crystal and Molecular Structures of [B(H2pdn)(Hpdn)]·H2O and [Ph2B(H2pdn)] (H3pdn = Pyridoxine)
Authors: de Sousa Adriana T. , Bessler Karl E. , Lemos Sebastia–o S. , Gomes Fernanda B. , Casagrande Gleison A. , Schulz Lang Ernesto
Published: April 2007

The 1:2 complex of boric acid with pyridoxine (1) crystallizes from aqueous solution as monohydrate in the triclinic space group ${\rm P}{\bar 1}$. The molecular structure of 1 corresponds to the expected bis‐chelate containing two non‐equivalent pyridoxinate ligands, one of them being dianionic and the other one monanionic, betain‐like with a protonated pyridine nitrogen atom. In the crystal structure hydrogen bonding, involving the water molecule, provides a supramolecular arrangement in form of sheets parallel to [011]. The 1H and 13C NMR spectra of 1 reveal a fast proton exchange between the two ligands in aqueous solution. Two new boron‐pyridoxine complexes [Ph2B(H2pdn)] (2) and [B(C2O4)(H2pdn)] (3) (H3pdn = pyridoxine) were prepared and characterized. In The crystal structure of 2 (monoclinic, P21/c) the molecules are linked to chains by N‐H···O hydrogen bonds along the b axis.
Synthesis, Crystal Structure and Supramolecular Organization of the 1D Coordination Polymer [Cu(HCOO)2(4‐bpytm)], (4‐bpytm = Bis(4‐pyridylthio)methane)
Authors: Carballo Rosa , Covelo Berta , García‐Martínez Emilia , Lago Ana B. , Vázquez‐López Ezequiel M.
Published: April 2007

The reaction of the flexible pyridyl dithioether ligand Bis(4‐pyridylthio)methane (4‐bpytm) with copper(II) formiate led to the formation of the coordination polymer [Cu(HCOO)2(4‐bpytm)]n, which has been characterized structurally. The copper atom is in a square‐planar environment and 4‐bpytm acts as an N,N′‐bis(monodentate) bridging ligand creating an onedimensional polymeric arrangement. The formiate ligand plays a key role in the supramolecular organization of the chains via CHformiate…Oformiate and CH4bpytm…Oformiate hydrogen bonds.
Synthesis and Characterization of Vanadium(IV) and (V) Complexes with 2‐Hydroxy‐acetophenone‐semicarbazone (H2hasc) as Ligand. X‐Ray Crystal Structures of [VO2(H2hasc)] and [VO2(Hhasc)]
Authors: da S. Maia Pedro Ivo , Deflon Victor M. , de Sousa Gerimário F. , Lemos Sebastia–o S. , Batista Alzir A. , Nascimento Otaciro R. , Niquet Elke
Published: April 2007

Three novel vanadium complexes with pharmacologically active ligands were synthesized and characterized: [VIVO(acac)(Hhasc)], [VIVO2(H2hasc)], and [VVO2(Hhasc)], where H2hasc = 2‐Hydroxy‐acetophenone‐semicarbazone. The analytical methods used included FTIR, 1H‐, 13C‐, 51V‐NMR and EPR spectroscopies, elemental analysis and X‐ray diffractometry from single crystals. The crystal and molecular structures of [VIVO2(H2hasc)] and [VVO2(Hhasc)] were determined. [VIVO2(H2hasc)] crystallizes monoclinic [P21/c, Z = 4, a = 783.4(2), b = 1024.9(2), c = 1365.5(3) pm, β = 99.506(14)°]. The (VO2)2+ core is coordinated to a neutral O,N,O‐tridentate unit of the H2hasc ligand, with the vanadium atom showing a square pyramidal coordination sphere. In the crystal of [VVO2(Hhasc)], triclinic [${\rm P}{\bar 1}$, Z = 4, a = 858.73(11), b = 967.39(5), c = 1318.63(12) pm, α = 97.423(5), β = 101.590(6), γ = 98.144(5)°], two symmetry independent (VO2)+ cores are observed. Each of them coordinates to a monodeprotonated Hhasc− unit, in a O,N,O‐tridentate mode. One assumes a square pyramidal geometry for the pentacoordinate vanadium(V) center. An additional interaction is observed for the other one, involving the phenolate oxygen atom from a symmetry related unit, resulting in a [5+1]‐coordination number for the transition metal atom.
Zr50Sc12O43N50 and Zr3Sc4N8 – Synthesis, Neutron Powder Diffraction and Raman Spectroscopy
Authors: Martinez Meta N. J. , Schweda E. , Boysen H. , Haug A. , Chassé T. , Hoelzel M.
Published: April 2007

The nitridation of Zr50Sc12O118 (Zr0.807Sc0.193O1.90), an anion deficient fluorite related compound, with ammonia yields at 1100 °C a green product with composition Zr1.613Sc0.387O1.387N1.613. This compound crystallizes cubic in space group $Ia{\bar 3}$ (a = 1007.8(5) pm) and is isostructural to Bixbyite with statistical distribution of Zr/Sc at the cation and of O/N at the anion sites. These are the results of Rietveld refinements from a powder neutron diffraction experiment. If Zr3Sc4O12 (Zr0.429Sc0.571O1.714), an educt with another Zr/Sc ratio, is nitridated with ammonia the reaction path shows again the formation of a compound with a bixbyite structure, but finally at 1200 °C a red nitride with the composition Zr3Sc4N8 (Zr0.375Sc0.5N) is formed. This compound has a cation deficient NaCl type structure (space group is $Fm{\bar 3}m$) with a = 452.8(1) pm. Neutron diffraction revealed again no ordering on the cation sites. Both compounds show an unperturbed N≡N stretching frequency in their Raman spectrum at 2327 cm−1. Zr3Sc4N8 exhibits at 1552 cm−1 a second sharp line which was assigned to a N22− moiety.
Zink‐katalysierte Alkoholyse von β‐Lactonen und aktivierten β‐Lactamen
Authors: Groß F. , Brombacher H. , Vahrenkamp H.
Published: April 2007

Zinc‐Catalyzed Alcoholysis of β‐Lactones and Activated β‐Lactams

In the presence of methanol or ethanol the complex TpPh,MeZn‐OH acts as a catalyst for the ring opening of β‐butyrolactone and N‐nitrophenyl substituted β‐propiolactams, resulting in the formation of the esters of β‐hydroxybutyric acid and N‐substituted β‐aminopropionic acids.
Alkali Salts of 5‐Aminotetrazole – Structures and Properties
Authors: Ernst Veronika , Klapötke Thomas M. , Stierstorfer Jörg
Published: April 2007

Alkali salts of 5‐aminotetrazole (5‐At) are common intermediates in synthesis of alkylated aminotetrazoles and their derivatives and can also be used as coloring agents in modern pyrotechnics, due to their high nitrogen content. The crystal structures of A+ 5‐At– * × H2O (A = Li+ (6), Na+ x = 3 (7), K+ (8), Rb+ (9) and Cs+ (10)) were determined using single crystal X‐ray diffraction and a detailed description is given in this work. In addition the compounds were characterized using vibrational (IR and Raman) and NMR spectroscopy, elemental analysis and differential scanning calorimetry (DSC). Since tetrazoles are known to be promising energetic materials the heats of formation were calculated using bomb calorimetric measurements and the sensitivities of all compounds were tested using BAM methods. They show no sensitivity towards friction (< 360 N) or impact (< 50 J). X‐ray determinations: 6: monoclinic, P21/c, a = 4.7900(5) Å, b = 10.6139(11) Å, c = 7.0369(8) Å, β = 103.260(9)°, V = 348.22(7) Å3, Z = 4; 7: triclinic, $P{\bar 1}$, a = 5.8689(7) Å, b = 10.0258(9) Å, c = 12.1710(12) Å, α = 87.335(11)°, β = 77.546(9)°, γ = 80.059(9)°, V = 688.76(13) Å3, Z = 4; 8: monoclinic, P21/c, a = 9.8516(9) Å, b = 6.8702(8) Å, c = 6.8372(7) Å, β = 115.613(11)°, V = 417.29(8) Å3, Z = 4; 9: orthorhombic, Pnma, a = 7.4221(9) Å, b = 6.8053(8) Å, c = 9.0133(9) Å, V = 455.26(9) Å3, Z = 4; 10: orthorhombic, Pnma, a = 8.0538(7) Å, b = 6.9305(6) Å, c = 9.1021(8) Å, V = 508.05Å3, Z = 4.
Zwei Nitridchloride des Wolframs: W2NCl8 und W2NCl9
Authors: Weisser Martina , Tragl Sonja , Meyer H.‐Jürgen
Published: April 2007

Two Tungsten Nitride Chlorides: W2NCl8 and W2NCl9

A solid state reaction of tungsten(VI)chloride and cyanamide yielded black crystals of W2NCl8 and red plate‐like crystals of W2NCl9. The structures of these compounds were determined by single crystal X‐ray diffraction. The crystal structure of W2NCl8 contains [Cl2/2Cl3WNWCl3Cl2/2]‐units forming chains along the c‐axis. The tungsten atoms are linked by a symmetric nitrido bridge (d(W–N) = 1.8203(4) Å). The crystal structure of W2NCl9 contains a dichloro‐bridged dimer of a nitride‐bridged ditungsten unit [Cl5WNWCl3Cl2/2]2 with two different W–N distances of 1.726(9) Å and 2.012(9) Å.
Silver(I) Complexes of 1,3‐Dialkyl‐4,5‐dimethylimidazol‐2‐ylidenes and their Use as Precursors for the Synthesis of Rhenium(V) NHC Complexes
Authors: Oehlke Elisabeth , Kückmann Theresa , Abram Ulrich
Published: April 2007

Ag(BF4) reacts with N‐heterocyclic carbenes (NHC) of the type 1,3‐dialkyl‐4,5‐dimethylimidazol‐2‐ylidene (LR, R = Me, Et, i‐Pr) under formation of [Ag(LR)2]+ complexes. [Ag(LEt)2](BF4) and [Ag(Li‐Pr)2](BF4) can be isolated from such procedures as air‐stable solids, while the methyl derivative decomposes rapidly in the reaction mixture. The Ag–carbene bond lengths in [Ag(Li‐Pr)2](BF4) are 2.08(1) Å. This is in accordance with the bonding situation in other Ag NHC complexes and does on its own not allow conclusions to be drawn concerning the bonding order or the reactivity of the compound.

Reactions of [Ag(LEt)2](BF4) with common rhenium(V) starting materials such as [ReOCl3(PPh3)2] or (NBu4)[ReOCl4] give the known ReV NHC complex [ReO2(LEt)4]+. This transmetallation reaction represents a new approach to rhenium or technetium NHC complexes which possess potential for applications in nuclear medicine.
Organometallic Compounds of the Lanthanides. 181 Alkyllanthanide Carbene Complexes
Authors: Schumann Herbert , Freckmann Dominique M. M. , Schutte Stefan , Dechert Sebastian , Hummert Markus
Published: April 2007

Ln(CH2SiMe3)3(THF)2 react with 1,3‐di‐iso‐propyl‐4,5‐dimethylimidazol‐2‐ylidene (ImMe2iPr2) yielding Ln(CH2SiMe3)3(THF)(ImMe2iPr2) (1, Ln = Er and 2, Ln = Lu). Reaction of 1 and 2 with an excess of ImMe2iPr2 results in the formation of the heteroleptic alkyllanthanide complexes Ln(CH2SiMe3)3(ImMe2iPr2)2 (3, Ln = Er) and (4, Ln = Lu). The molecular structures of 1, 2, and 4 show a distorded trigonal bipyramidal arrangement around the lanthanide centers with two alkyl ligands and one carbene in the equatorial positions.
Polyol Metal Complexes. Part 54 Multiply Deprotonated Purine Nucleosides as Ligands in Bismutates and Antimonates
Authors: Klüfers Peter , Mayer Peter
Published: April 2007

The crystal structures of [Co(NH3)6][Bi(Guo1,2′,3′H−3)2] · 9 H2O (1), Na[Sb(Ado2′,3′H−2)2] · H2O (2), and Na2[Bi(Ado2′,3′H−2)(Ado2′,3′,5′H−3)] · 13.5 H2O (3) were determined from single‐crystal X‐ray diffraction data (Guo = guanosine, Ado = Adenosine). The chelate complex anions of all structures consist of a bismuth(III) or antimony(III) center which is coordinated by the 1,2‐diolato group of the ribofuranosyl moiety of the nucleosides. In 1, two guanine moieties belonging to different complexes are linked by two hydrogen bonds of the type N2–H···N3. 13C NMR data obtained from the mother liquors show a coordination‐induced shift for the coordinating alkoxido groups of guanosine and adenosine as well as inosine.
Polyol Metal Complexes. Part 55 Germanes with Alkylenedioxy Substituents
Authors: Klüfers Peter , Vogler Constance
Published: April 2007

Within this work five novel germanes with alkylenedioxy substituents derived from 1,2‐diols have been synthesized and structurally characterized. Various coordination patterns from tetra‐ to hexacoordination were determined. Both open‐chain and cyclic 1,2‐diols such as 1,2‐ethandiol (Ethd), 1,1′‐bicyclohexyl‐1,1′‐diol (Bhxd), cis‐oxolane‐3,4‐diol (AnEryt) and cis‐1,2‐cyclopentanediol (cis‐1,2‐Cptd) were used. Tetracoordination of the germanium atom in the crystalline state appears to be restricted to sterically demanding substituents.

In general, the tendency of germanium to extend its coordination sphere to build penta‐ or hexacoordinate compounds is demonstrated. It is also shown that germanium is able to compensate a lack of substituents by the formation of dimeric structures.
Laparoscopic Nissen‐Rossetti Fundoplication with Routine Use of Intraoperative Endoscopy and Manometry: Technical Aspects of a Standardized Technique
Authors: del Genio Gianmattia , Rossetti Gianluca , Brusciano Luigi , Limongelli Paolo , Pizza Francesco , Tolone Salvatore , Fei Landino , Maffettone Vincenzo , Napolitano Vincenzo , del Genio Alberto
Published: April 2007

Background

Several different ways of fashioning a total fundoplication lead to different outcomes. This article addresses the technical details of the antireflux technique we adopted without modifications for all patients with GERD beginning in 1972. In particular it aims to discuss the relation between the mechanism of function of the wrap and the physiology of the esophagus.

Methods

The study population consisted of 380 patients affected by GERD with a 1‐year minimum of follow‐up who underwent laparoscopic Nissen‐Rossetti fundoplication by a single surgeon.

Results

No conversion to open surgery and no mortality occurred. Major complications occurred in 4 patients (1.1%). Follow‐up (median 83 months; range: 1–13 years) was achieved in 96% of the patients. Ninety‐two percent of the patients were satisfied with the results of the procedure and would undergo the same operation again. Postoperative dysphagia occurred in 3.5% of the patients, and recurrent heartburn was observed in 3.8%.

Conclusions

Laparoscopic Nissen‐Rossetti fundoplication with the routine use of intraoperative manometry and endoscopy achieved good outcomes and long‐term patient satisfaction with few complications and side‐effects. Appropriate preoperative investigation and a correct surgical technique are important in securing these results.
Recurrence Pattern of Squamous Cell Carcinoma in the Middle Thoracic Esophagus after Modified Ivor‐Lewis Esophagectomy
Authors: Chen Gang , Wang Zhou , Liu Xiang‐yan , Liu Fan‐ying
Published: April 2007

Background

Despite increasingly radical surgery for esophageal carcinoma, many patients still develop tumor recurrence after operation. This study was designed to evaluate the recurrence pattern of squamous cell carcinoma in the middle thoracic esophagus after modified Ivor‐Lewis esophagectomy.

Methods

We retrospectively reviewed data of 196 patients who underwent modified Ivor‐Lewis esophagectomy with two‐field lymph node dissection from January 1997 to January 2001. Recurrence was classified as locoregional or hematogenous recurrence. Logistic regression analysis was performed to identify risk factors of postoperative recurrence.

Results

The overall 3‐year and 5‐year survival rates in all patients were 53% and 31%, respectively. Recurrence was recognized in 96 patients (48.9%) in the 3 years after operation. The median time to tumor recurrence was 12.2 months. The pattern of recurrence was locoregional in 52 patients (mainly mediastinal in 41, single cervical/supraclavicular in 8), hematogenous in 44 patients (simultaneous locoregional and hematogenous in 10; mainly liver, bone, or lung in 39). The locoregional recurrence rate was significantly lower in patients with postoperative radiotherapy than that in patients without postoperative radiotherapy (p = 0.02). Logistic regression analysis showed that T3 (p = 0.032), N1 (p = 0.003), and postoperative radiotherapy (p = 0.022) were independent risk factors for tumor locoregional recurrence.

Conclusions

About one half of the patients would develop recurrent disease within 3 years after modified Ivor‐Lewis esophagectomy with two‐field lymph node dissection, and most of them had mediastinal lymph node, liver, bone, or lung metastasis. Postoperative radiotherapy was beneficial in the control of locoregional recurrence.
Coagulopathy: Its Pathophysiology and Treatment in the Injured Patient
Authors: Tieu Brandon H. , Holcomb John B. , Schreiber Martin A.
Published: April 2007

Hemorrhage continues to be one of the leading causes of death following trauma. Trauma patients are susceptible to the early development of coagulopathy and the most severely injured patients are coagulopathic on hospital admission. Hypothermia, acidosis, and dilution from standard resuscitation can worsen the presenting coagulopathy and perpetuate bleeding. Early identification of coagulopathy is dependent on clinical awareness and point of care laboratory values. Routinely used laboratory coagulation parameters fail to adequately describe this state. Thrombelastography is a test that can be done at the bedside and uses whole blood to provide a functional evaluation of coagulation. Rapid diagnosis of coagulopathy, followed by prevention or correction of hypothermia and acidosis should be a priority during the initial evaluation and resuscitation. Judicious use of resuscitation fluids and early replacement of coagulation factors will help prevent iatrogenic hemodilution. This review covers the pathophysiology as well as the clinical and laboratory diagnosis of coagulopathy. Prevention and treatment strategies are discussed, including early transfusion of coagulation factors during massive transfusion and the use of recombinant factor VIIa. Damage control resuscitation is briefly discussed, and it involves the combination of hypotensive resuscitation and hemostatic resuscitation. Finally, a description of the use of fresh whole blood in the military setting is included. Its use has been proven to be safe and beneficial in this setting and warrants further investigation as an adjunct to the management of civilian trauma patients.
Intrathyroidal Differentiated Thyroid Carcinoma: Tumor Size‐Based Surgical Concepts
Authors: Miccoli Paolo , Minuto Michele N. , Ugolini Clara , Panicucci Erica , Berti Piero , Massi Marco , Basolo Fulvio
Published: April 2007

Introduction

Total thyroidectomy (TT) remains the treatment of choice for differentiated thyroid carcinomas (DTCs), but a limited approach can be proposed when tumors are at an early stage and limited to a single lobe. The aim of this study was to analyze the pathologic and clinical aspects of a retrospective series of DTCs in an attempt to determine whether these features might prove useful for limiting the surgical strategy in selected cases.

Methods

From 2000 to 2005, a total of 2798 patients (637 males, 2161 females; mean age 44.6 years) underwent TT for papillary thyroid carcinoma in our department. The histologic features considered were size, histologic subtype and capsule of the tumor, its multifocality/bilaterality, infiltration of the thyroid capsule, and the presence of nodal metastases.

Results

Statistical analysis revealed that among tumors ≤ 1 cm the presence of the tumor capsule, infiltration of the thyroid capsule, bilaterality, and the presence of node metastases were all significantly lower when the tumor size was ≤ 0.5 cm (p < 0.0001). Furthermore, patients with bilateral carcinomas demonstrated a significantly higher presence of a tumor capsule (p = 0.012), infiltration of the thyroid capsule (p < 0.0001), and node metastases (p < 0.0001) and a higher incidence of the “tall‐cells” variant (p < 0.0001) when compared to the unilateral population.

Conclusions

Based on these data it is suggested that tumors ≤ 1 cm cannot be considered a homogeneous class of DTCs. Nevertheless, in tumors ≤ 0.5 cm the absence of a “tall‐cells” variant and the absence of infiltration of the thyroid capsule might be useful for avoiding an unnecessary completion thyroidectomy after lobectomy.
Evidence‐based Approach to the Management of Sporadic Medullary Thyroid Carcinoma
Authors: Moley Jeffrey F. , Fialkowski Elizabeth A.
Published: April 2007

Medullary thyroid carcinoma (MTC) is a rare malignancy of the thyroid C cells. It occurs in hereditary (25% of cases) and sporadic (75%) forms. Sporadic MTCs frequently metastasize to cervical lymph nodes. Thorough surgical extirpation of the primary tumor and nodal metastases by compartment‐oriented resection has been the mainstay of treatment (level IV evidence). Surgical resection of residual and recurrent disease is effective in reducing calcitonin levels and controlling complications of central neck disease (level IV evidence). Radioactive iodine, external beam radiation therapy, and conventional chemotherapy have not been effective. Newer systemic treatments, with agents that target abnormal RET proteins hold promise and are being tested in clinical trials for patients with metastatic disease.
Role of Surgeons in Clinical Trials for Thyroid Cancer
Authors: You Y. Nancy , Wells Samuel A.
Published: April 2007

Properly performed clinical trials provide a foundation for evidence‐based medical practice. The surgeon plays a central role in the management of patients with malignant solid tumors, including thyroid cancer, because operative extirpation of the malignancy is the essential first step in effective therapy. This article discusses the role of the surgeon in the clinical research of thyroid cancer and also reviews the important clinical trials that have influenced the treatment of patients with thyroid cancer. Recent discoveries defining the genetic mutations underlying the various types of thyroid cancers have led to the development of targeted therapies. These chemical compounds, which are now being evaluated in clinical trials, hold great promise for the treatment of patients with locally advanced and distant metastatic disease. The surgical investigator also plays an important role in procuring tumor tissue from patients in clinical trials. The molecular analysis of these tissues is of critical importance in selecting specific therapies and predicting patient response and prognosis.
Transient Liver Dysfunction after Laparoscopic Gastrectomy for Gastric Cancer Patients
Authors: Etoh Tsuyoshi , Shiraishi Norio , Tajima Masaaki , Shiromizu Akio , Yasuda Kazuhiro , Inomata Masafumi , Kitano Seigo
Published: April 2007

Introduction

The effect of laparoscopic surgery under CO2 pneumoperitoneum on liver function is not clear. The aim of this study was to clarify whether laparoscopy‐assisted distal gastrectomy (LADG) is associated with changes in liver function compared with open distal gastrectomy (ODG).

Methods

A total of 205 patients who underwent LADG (n = 147) or ODG (n = 58) between January 1994 and April 2004 were included in this study. Liver function tests—aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin, total bilirubin—were examined before surgery and at 1, 3, and 7 days after surgery. The postoperative clinical course was compared between the two groups.

Results

AST levels on day 1 and ALT levels on days 1 and 3 were significantly higher in the LADG group. Albumin levels showed a marked decrease after operation in both groups, but the level recovered more rapidly in the LADG group than in the ODG group, showing significant differences on days 3 and 7. The total bilirubin levels remained unchanged from baseline. The postoperative complication rate was similar in the two groups, although 3 LADG patients among the 27 patients with liver disease suffered severe enteritis.

Conclusions

Transient liver dysfunction was documented in patients after laparoscopic gastrectomy under CO2 pneumoperitoneum.
A Single Surgical Unit’s Experience with Abdominal Tuberculosis in the HIV/AIDS Era
Authors: Clarke D.L. , Thomson S.R. , Bissetty T. , Madiba T.E. , Buccimazza I. , Anderson F.
Published: April 2007

Introduction

Human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) has resulted in a resurgence of abdominal tuberculosis in South Africa, and these patients often present to general surgeons. We describe a single‐hospital experience in a region of high HIV prevalence.

Methods

A prospective database of all patients with suspected abdominal tuberculosis was maintained from January 2003 until July 2005.

Results

There were 67 patients (20 men, 47 women) with an average age of 32 years (range 27–61 years). The erythrocyte sedimentation rate was universally elevated (105 ± 23). Altogether, 23 patients were HIV‐positive and 7 were HIV‐negative. The status was unknown in the remainder. Chest radiographs demonstrated an abnormality in 17 patients (22%). Abdominal ultrasonography was performed in 59 patients and computed tomography in 12. Twelve laparotomies were performed, seven as emergencies. None in the elective laparotomy group died, whereas the mortality rate in the emergency group was 60%. Laparoscopy was insufficient for a variety of reasons. Two patients underwent appendectomy and two excision of a perianal fistula. Two patients underwent biopsy of a palpable subcutaneous node, which confirmed the diagnosis in both cases. A definitive diagnosis was achieved in all 12 patients subjected to laparotomy and at colonoscopic biopsy in 2, lymph node biopsy in 2, appendectomy in 2, perianal fistulectomy in 2, and percutaneous drainage in 2. In the remaining 47 patients the diagnosis was made on the basis of the clinical presentation and radiologic imaging. The patients were commenced on antituberculous therapy. The in‐hospital mortality in this group was 10%. Therapy was continued at a centralized tuberculosis facility independent of the hospital. Surgical follow‐up was poor, with only five (7%) patients completing the 6‐month review at a surgical clinic.

Conclusions

A resurgence in tuberculosis during the HIV era produces a new spectrum of presentations for the surgeon. Emergency surgery is associated with high mortality. Bacterial and histologic evidence of infection are difficult to obtain, and indirect clinical and imaging evidence are used to commence a trial of therapy. A short‐term clinical response is regarded as proof of disease. Lack of follow‐up means that the efficacy of this strategy is unproven. Health policy changes are needed to enable appropriate surgical follow‐up to determine the most effective management algorithm.
Prevalence of markers of heart failure in patients with atrial fibrillation and the effects of ximelagatran compared to warfarin on the incidence of morbid and fatal events: A report from the SPORTIF III and V trials
Authors: Cleland John G.F. , Shelton Rhiddian , Nikitin Nikolay , Ford Sarah , Frison Lars , Grind Margaretha
Published: April 2007

Background:

Patients with atrial fibrillation (AF) who also have heart failure have a worse outcome but the diagnosis of heart failure is often missed.

Aim:

To compare the effects of warfarin and ximelagatran on morbidity and mortality in patients with AF with and without markers of heart failure.

Methods and results:

Data for 7329 patients from two randomised controlled trials were merged. Treatment with loop diuretics or the presence of left ventricular dysfunction, were used as markers of possible heart failure. The 3555 (49%) patients with markers of heart failure had higher composite event rates on warfarin (10.81% per year [py] [95% CI 9.59 to 12.13]) compared to the 3774 (51%) patients without markers of heart failure (4.18% py [95% CI 3.44 to 5.01]). The composite event rate was lower on ximelagatran overall (6.18% py [95% CI 5.51 to 6.89] versus 7.34% py [95% CI 6.63 to 8.10] on warfarin; P=0.0219 for the difference) with similar effects in each trial and in patients with and without markers of heart failure, mainly due to fewer heart‐failure events (hazard ratio 0.69 [95% CI 0.54 to 0.87]; P<0.001).

Conclusions:

Patients with markers of heart failure, even if the diagnosis is not well established, are at increased risk of thromboembolic events and might be targeted for more effective antithrombotic therapy. This might include patients in sinus rhythm as well as AF.
Effect of supplementation of women in high-risk pregnancies with long-chain polyunsaturated fatty acids on pregnancy outcomes and growth measures at birth: a meta-analysis of randomized controlled trials
Authors: Horvath Andrea , Koletzko Berthold , Szajewska Hania
Published: April 2007

It is hypothesized that the intake of long-chain PUFA (LC-PUFA) throughout pregnancy could protect against pre-eclampsia, pregnancy-induced hypertension or intra-uterine growth retardation, and is essential for optimal neural development. The objective of the present study was to systematically evaluate the effect of LC-PUFA supplementation of high-risk pregnant women's diets on pregnancy outcomes and growth measures at birth. We searched MEDLINE, EMBASE, CINAHL and the Cochrane Library through March 2006 and references in reviewed articles for randomized controlled trials (RCT) comparing LC-PUFA supplementation with placebo or no supplementation in women with high-risk pregnancies. We found no evidence that supplementation influenced the duration of pregnancy or the percentage of preterm deliveries < 37 weeks of gestation. However, compared with controls, supplementation was associated with a significantly lower rate of early preterm delivery ( < 34 weeks of gestation) (two RCT; n 291; relative risk 0·39 (95 % CI 0·18, 0·84)). There was no significant difference in the infant birth weight, the rate of low birth weight ( < 2500 g or < 10th percentile) and the recurrence of intra-uterine growth retardation. Other pregnancy outcomes (for example, the rate of pregnancy-induced hypertension, the rate of pre-eclampsia and the rate of Caesarean section) were also similar in both groups. In conclusion, the present data suggest that supplementation with n-3 LC-PUFA in women with high-risk pregnancies reduced the risk of early preterm delivery in the fatty acid-supplemented group compared with the placebo group, while no other effects on pregnancy outcomes were detected.
MEDICAL MISSIONARIES AND MODERNIZING EMIRS IN COLONIAL HAUSALAND: LEPROSY CONTROL AND NATIVE AUTHORITY IN THE 1930S
Authors: SHANKAR SHOBANA
Published: April 2007

This article argues that emirs modernized and enhanced their authority through cooperation with Christian missions in the anti-leprosy campaign in colonial Hausaland in the 1930s. New documentary and oral sources detail how Native Administrations and Sudan Interior Mission workers together established leprosaria that were important beyond religious interaction. Emirs translated Islamic ideals of charity into governmental responsibility for medical welfare. The leprosy scheme brought together the elite and non-elite in ways that would previously have been unimaginable and took emirs' power to new reaches in an era of expanding native authority in Nigeria and throughout much of British Africa.
READING, WRITING AND RALLIES: THE POLITICS OF ‘FREEDOM’ IN SOUTHERN BRITISH TOGOLAND, 1953–1956
Authors: SKINNER KATE
Published: April 2007

Examples of chant, song and written propaganda from the mid-1950s are examined here in order to probe the debates and relationships which influenced the political future of the Ewe-speaking areas of southern British Togoland. While microstudies have been important in explaining sources of division between communities in these areas, propaganda provides a means of understanding the arguments, idioms and ideas about the state which brought many different people together behind the apparently peculiar project of Togoland reunification. The main source of tension within this political movement was not competing local or communal interests, but the unequal relationships that resulted from uneven provision of education. Written and oral propaganda texts, and the rallies where they were performed and exchanged, point to a surprisingly participatory and eclectic political culture, where distinctions between the lettered and unlettered remained fluid and open to challenge.
Choosing a paediatric tracheostomy tube: an update on current practice
Authors: Tweedie D J , Skilbeck C J , Cochrane L A , Cooke J , Wyatt M E
Published: April 2007

Objectives:

A variety of paediatric tracheostomy tubes are available. This article reviews those in current use at Great Ormond Street Hospital.

Methods:

We outline our preferences and the particular indications for the different tubes, speaking valves and other attachments.

Results:

Practice has changed significantly in recent years. One product has been re-sized by its manufacturer; others are no longer commonly used. An updated sizing chart is included for reference purposes, together with manufacturers' contact details.

Conclusions:

The choice of paediatric tracheostomy tube is driven by clinical requirements. A small range of tubes are suitable for the majority of children, but some will require other varieties in specific circumstances.
Spherical splitting of 3-orbifolds
Authors: PETRONIO CARLO
Published: April 2007

The famous Haken–Kneser–Milnor theorem states that every 3-manifold can be expressed in a unique way as a connected sum of prime 3-manifolds. The analogous statement for 3-orbifolds has been part of the folklore for several years, and it was commonly believed that slight variations on the argument used for manifolds would be sufficient to establish it. We demonstrate in this paper that this is not the case, proving that the apparently natural notion of “essential” system of spherical 2-orbifolds is not adequate in this context. We also show that the statement itself of the theorem must be given in a substantially different way. We then prove the theorem in full detail, using a certain notion of “efficient splitting system.”
Kummer theory for big Galois representations
Authors: DELBOURGO DANIEL , SMITH PAUL
Published: April 2007

In their 1990 paper, Bloch and Kato described the image of the Kummer map on an abelian variety over a local field, as the group of 1-cocycles which trivialise after tensoring by Fontaine's mysterious ring BdR. We prove the analogue of this statement for the universal nearly-ordinary Galois representation. The proof uses a generalisation of the Tate local pairing to representations over affinoid K-algebras.
The abelianization of the congruence IA-automorphism group of a free group
Authors: SATOH TAKAO
Published: April 2007

We consider the abelianizations of some normal subgroups of the automorphism group of a finitely generated free group. Let Fn be a free group of rank n. For d ≥ 2, we consider a group consisting the automorphisms of Fn which act trivially on the first homology group of Fn with ${\mathbf Z}$/d${\mathbf Z}$-coefficients. We call it the congruence IA-automorphism group of level d and denote it by IAn,d. Let IOn,d be the quotient group of the congruence IA-automorphism group of level d by the inner automorphism group of a free group. We determine the abelianization of IAn,d and IOn,d for n ≥ 2 and d ≥ 2. Furthermore, for n=2 and odd prime p, we compute the integral homology groups of IA2,p for any dimension.
The Aging lung
Authors: Dyer Christopher AE , Stockley Robert A
Published: April 2007

The human lung is a resilient and complex organ, capable of uninterrupted functioning without defect over a lifetime. While there is a body of knowledge regarding macroscopic and physiological changes that occur in the lung with age, there is still much to be understood. In itself this is not surprising given the complex interaction of intrinsic and extrinsic factors that might play a role in these changes. Lung tissue is highly susceptible to environmental factors, which can have an impact over the course of a lifetime, including smoking, pollutants, occupation and nutrition.
Changes in biomass carbon stocks in China's grasslands between 1982 and 1999
Authors: Piao Shilong , Fang Jingyun , Zhou Liming , Tan Kun , Tao Shu
Published: April 2007

Terrestrial ecosystems in the northern latitudes are significant carbon sinks for atmospheric CO2; however, few studies come from grassland ecosystems. Using national grassland resource inventory data, NDVI (normalized difference vegetation index) time series data set, and a satellite‐based statistical model, this study identifies changes in the size and distribution of aboveground biomass carbon (C) stocks for China's grasslands between 1982 and 1999. Biomass C stocks averaged 145.4 Tg C for the study period for a total area of 334.1 × 104 km2, and have increased by 17.7 Tg C (1 Tg = 1012 g) from 136.3 Tg C in the early 1980s (average of 1982–1984) to 154.0 Tg C in the late 1990s (average of 1997–1999), with an annual increase of 0.7%. This suggests that the aboveground biomass of China's grasslands may have functioned as the C sinks in the past 2 decades. Assuming a constant ratio of aboveground to belowground biomass for each grassland type, we also estimated belowground biomass C and its change over time for each grassland type, generating an average estimate of 1051.1 Tg C for the total (aboveground and belowground) biomass C and an annual increase of 126.67 Tg C for China's grasslands over the 18 years. However, the accuracy of these estimates has limitations due primarily to uncertainties in estimates of belowground C, biomass inventories, and satellite time series data sets.
Response of sea surface properties to Hurricane Dennis in the eastern Gulf of Mexico
Authors: Hu Chuanmin , Muller‐Karger Frank E.
Published: April 2007

Sea Surface Reflectance (SSR) and Sea Surface Temperature (SST) were assessed in the eastern Gulf of Mexico in early July 2005 after passage of Hurricane Dennis, a category 4 storm, using data from the MODIS, SeaWiFS, and AVHRR satellite sensors, historical hydrographic and nutrient surveys, and a simple vertical water column mixing model. The bathymetric gradient across the shelf break, the offshore deep nutricline, and nearby Loop Current eddies led to unique SSR and SST changes after the passage of Dennis. In waters shallower than 50 m, a strong sediment resuspension event led to higher SSR in the visible and an increase in the MODIS fluorescence line height (FLH). These variables returned to pre‐storm conditions after about 10 days. The FLH change indicates increasing biomass in the short response time (<2 days), which might have been due to resuspended benthic and/or near‐bottom algae, as opposed to simply new primary production in the overlying water column. The SST changes occurred almost entirely along the right side of the hurricane track (−1.96 ± 0.66°C for an area of 158,600 km2). Waters >50 m deep cooled down significantly, but there was no apparent change in SSR, presumably because the nutricline was too deep to be affected by vertical mixing due to the storm. The three‐dimensional hydrographic and nutrient structure in waters near the west Florida shelf defines what changes may be detected at the surface with remote sensing.
Rates of thermohaline recovery from freshwater pulses in modern, Last Glacial Maximum, and greenhouse warming climates
Authors: Bitz C. M. , Chiang J. C. H. , Cheng W. , Barsugli J. J.
Published: April 2007

Recovery rates of the thermohaline circulation after a freshwater pulse in the North Atlantic vary considerably depending on the background climate, as demonstrated in the Community Climate System Model. The recovery is slowest in a Last Glacial Maximum (LGM) climate, fastest in a modern climate, and intermediate between the two in a greenhouse warming (4XCO2) climate. Previously proposed mechanisms to explain thermohaline circulation stability involving altered horizontal freshwater transport in the North Atlantic are consistent with relative recovery rates in the modern and 4XCO2 climates, but fail to explain the slow LGM recovery. Instead, sea ice expansion inhibits deep‐water formation after freshening in the LGM climate by reducing heat loss to the atmosphere and providing additional surface freshwater. In addition, anomalous vertical freshwater transport across ∼1 km depth after freshening is most effective at weakening the stratification in the modern case but is negligible in the LGM case.
Plume mantle source heterogeneity through time: Insights from the Duarte Complex, Hispaniola, northeastern Caribbean
Authors: Escuder‐Viruete Javier , Pérez‐Estaún Andrés , Contreras Fernando , Joubert Marc , Weis Dominique , Ullrich Thomas D. , Spadea Piera
Published: April 2007

Located in the Cordillera Central of Hispaniola, the Duarte Complex offers an opportunity to study an on‐land fragment of the Caribbean‐Colombian oceanic plateau. Geochemical, Sr‐Nd isotope, and 40Ar‐39Ar radiometric age data combined with detailed mapping have shown that the Duarte Complex includes two lithostratigraphic units, composed of four geochemical groups of metavolcanic rocks: Group Ia, low‐Ti high‐Mg basalts, and group Ib, high‐Ti picrites and primitive high‐Mg basalts, occur interlayered in the lowermost levels of the lower unit; group II, light rare earth element (LREE)‐enriched picrites, ferropicrites and high‐Mg basalts, forms the main lava sequence of the lower unit; and group III, LREE‐enriched Fe‐Ti basalts, is present exclusively in the upper unit. Nd isotope and incompatible trace element patterns are diverse in the Duarte Complex metavolcanics and are consistent with mantle sources related to a heterogeneous plume. Mantle melt modeling suggests that an early, extensive melting (10–20%) of shallow mantle resulted in the formation of relatively depleted group I and II magmas, whereas the late, more enriched group III magmas were the product of deeper, low‐degree (<3%) melting of a heterogeneous plume. Therefore plume mantle sources were more enriched and deeper through time. Foliated amphibolites of the Duarte Complex yield 40Ar‐39Ar hornblende plateau ages of 93.9 ± 1.4 and 95.8 ± 1.9 Ma (Cenomanian, 99.6–93.5 Ma) that demonstrate an older age of the protholiths, probably Albian (>96 Ma). Hence an Early Cretaceous phase of the Caribbean‐Colombian oceanic plateau construction is recorded in Hispaniola.
Numerical simulation of M2 internal tides in the South Brazil Bight and their interaction with the Brazil Current
Authors: Pereira A. F. , Castro B. M. , Calado L. , da Silveira I. C. A.
Published: April 2007

A fully three‐dimensional nonlinear primitive equation ocean model is applied to study the semidiurnal internal tide in the South Brazil Bight under summer conditions. Along the shelf break and upper slope of this region, the upper layer (0–600 m) is occupied by the southward flowing Brazil Current. Several numerical experiments were conducted to investigate the generation and propagation of the M2 internal tide. Using horizontally homogeneous and vertically stratified density fields, internal tides were generated over the whole Bight with a clear signal on the continental shelf. When a more realistic summer stratification was considered, a baroclinic jet, representative of the Brazil Current, developed and comparisons between current observations and modeled results were improved. This jet acts as a barrier to the coastward propagation of the internal tide generated over the slope, reflecting it back towards the open ocean. On the negative relative vorticity side of the Brazil Current, located over the shelf, internal tides are trapped, enhancing vertical current variability and, hence, tidally induced mixing. The results highlight the importance of considering background flows when investigating internal tides in regions of strong along‐slope baroclinic flows such as western boundary currents.
On improving the simulation of Atlantic Water circulation in the Arctic Ocean
Authors: Golubeva E. N. , Platov G. A.
Published: April 2007

We performed a set of numerical experiments in order to better simulate the circulation of Atlantic Water in the Arctic Ocean by employing a coupled ice‐ocean Arctic regional model. We found that the inflow of Atlantic Water via Fram Strait is weak in the case of high viscosity and diffusivity coefficients (1 · 108 cm2/s and 1 · 107 cm2/s) and creates an anticyclonic circulation in the Eurasian basin. This flow increases significantly when both coefficients are scaled down (to 1 · 107 cm2/s and 0.5 · 106 cm2/s) but the current path is then unstable, and it becomes mostly anticyclonic after about a decade of integration. A further reduction of these coefficients leads to growing instabilities due to insufficient grid resolution. Short‐term integration of the model with doubled space resolution shows better agreement with observations, but long‐term calculation is still restricted by simulation time. Alternatively, a lower resolution version of this model benefits from parameterizations of subscale processes. Incorporation of the Neptune parameterization of eddy‐topography interaction into the model intensifies the current steered by subsurface topography and results in cyclonic circulation of the Atlantic Water in every subbasin and in the whole Arctic region. In the absence of salinity restoring there was strong salinity drift at the surface, resulting in a salinity increase in the central Arctic by 3 units from 1960 to 2005. The Arctic freshwater content is driven basically by year‐to‐year variations of convective mixing involving more saline water from lower layers. After cooling and increasing in salinity through brine rejection, the surface water becomes denser, leading to even stronger convective mixing. One‐dimensional model tests showed how model performance could be improved by implementing a lower vertical diffusion coefficient and higher vertical resolution.
Effects of topography on the spin‐up of a Venus atmospheric model
Authors: Herrnstein A. , Dowling T. E.
Published: April 2007

We study how topography affects the spin‐up from rest of a model of the atmosphere of Venus. The simulations are performed with the EPIC model using its isentropic, terrain‐following hybrid vertical coordinate, and are forced with the Newtonian‐cooling profile used to achieve superrotation in a Venus model with no topography by Lee et al. (2005). We are able to reproduce their results with our model, which was developed independently and uses a different vertical coordinate. Both groups use a horizontal resolution of 5°, which is dictated by the need for reasonable computer runtime and is not a claim of numerical convergence. We find that the addition of topography substantially changes both the evolution and end state of the model's spin‐up: the magnitude of the superrotation is diminished from 55 ms−1 to 35 ms−1, and it reaches steady state faster, in a few years instead of a few decades. A large, stationary eddy associated with Ishtar Terra forms that has a local horizontal temperature anomaly of order 2 K at the 0.7 bar level; such a feature may be observable in high‐resolution infrared images.