bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of the Biological Response to Acetylsalicylic Acid by Platelet Occlusion Time in Pregnant Women in Brazzaville
Authors: Gokaba LT Ocko , Samba JA Elira , Atipo-Tsiba OF Galiba , Buambo GRJ , Ngolet LO , Iwandza RC , Amboulou P Issongo , Mboumba J Nziengui , Bango C , Itoua C , Dokekias A Elira
Published: January 2024

Low-dose acetylsalicylic acid (ASA) has been recommended for pregnant women since 2011 by the OMS to prevent thrombotic phenomena. Despite the variability of its clinical efficacy (resistance phenomena), its non-standardized biological monitoring can be performed using platelet occlusion time (POT). The aim of this study was to assess the response to ASA using POT.

A multicenter, cross-sectional, analytical study was conducted in the obstetrics and gynaecology departments of six Brazzaville hospitals over a period of 09 months and included pregnant women on ASA 100 mg daily for at least 7 days. POT was measured using the INNOVANCE® PFA®-200 system. The variables studied were clinical (age, medical and obstetrical history) and biological (blood count, POT). Non-response to ASA was defined by a POT of 150 seconds or less. Data analysis was performed using STATA 12 software. Logistic regression was used to assess the determinants associated with non-response. The incidence of obstetric complications according to ASA resistance was evaluated by the Kaplan-Meier method and the Log-Rank test. The significance threshold was p<0.005.

The study involved 39 pregnant women, mean age 33.9 ± 5.4 years, treated with ASA for hypertensive disorders of pregnancy n=19 (48.7%), chronic arterial hypertension n=7 (18%), diabetes n=3(7.7%) fetal death n=3(7.7%), unexplained miscarriage n=3(7.7%), advanced age n=2 (5.1%) and twin pregnancy n=2(5.1%). The median body index was 25.5 kg/m2 [23.7;29.4] with 35.9% women of normal weight, 48.7% overweight and 15.4% obese. Non-response to ASA was found in 12 pregnant women (30.7%). No statistically significant differences were observed between non-responders and responders with regard to epidemiological, clinical and haematological determinants (p>0.05). Non-response was more observed in women with complications 23.08% versus 7.7% (p=0,008).

Non-response to ASA, present in a third of hypertensive pregnant women, is associated with the occurrence of obstetrical complications in Brazzaville.
Yield Gap Analysis for Enhancement of Rice Production and Productivity under Rain-Fed Condition of Chandel, Manipur, India
Authors: Chongloi Khumlo Levish , Singh Deepak , Monsang Ts. Leenda , Singh I. Meghachandra , Anal Bs. Hmannihring , Devi A. Ameeta
Published: January 2024

The study was conducted at Chandel district, Manipur state aiming to assess the impact of rice production under Frontline Demonstration (FLD) in terms of yield, yield gap/extension gap, technological gap and economic gains during kharif season from 2018 to 2022. The present Front Line Demonstration on rice var. RC-Maniphou-13 was carried out by Krishi Vigyan Kendra, Chandel, ICAR-RC for NEH Region, Manipur Centre at 40 hectares in 92 farmers’ field of different villages. The result indicated that average grain yield of rice in demonstration field ranged between 57.60 to 60.60 q/ha whereas in farmers’ practices, it was 42.50 to 47.33 q/ha during demonstrated years. The percent increase in yield with Demonstration Practices over Farmers’ Practices ranged between 28.04 to 35.53. The yield gap/technological and extension gap were from 9.40 to 12.40 and 13.27 to 15.10 q/ha respectively. Similarly, technological index was decreased from 17.71 to 13.43 per cent during the study period. The benefit cost ratio was from 1.98 to 2.65 under demonstration, while it was from 1.09 to 1.91 under farmer practices. By conducting Front Line Demonstration on improved practices with HYV of proven technologies in farmers’ field, yield potential of rice enhanced to a great extent which increased in production and productivity, also the income level of farmers has improved the livelihood of farming community in the region by reducing the technology gaps.
Innovation to Improve Critical Thinking Skills in the Generation Z using Peeragogy as a Learning Approach and Artificial Intelligence (AI) as a Tool
Authors: Baskoro Gembong , Mariza Ita , Sutapa I Nyoman
Published: January 2024

The current generation, known as generation Z (Gen Z), is a generation that lives and is familiar with information technology in everyday life, including but not limited to learning purposes. Gen Z is characterized by teamwork in cyberspace and solving problems. Gen Z can also adopt artificial intelligence (AI) technology as their learning tool. Meanwhile, Gen Z faces the challenge of acquiring 21st-century skills requiring higher-order thinking (HOTS). This paper will focus on learning skills, especially critical thinking (CT). For this reason, it is essential to improve the competency of CT skills in Gen Z by using a model that combines the 7E learning cycle with peeragogy learning approach and adopting the latest AI applications as a tool. This model will contribute to the theoretical and practical use of AI apps for education, particularly the role of correct utilization of AI. Additionally, it can be misused to improve learning skills, especially CT skills. The results carried out in class show AI's effectiveness in improving CT skills for Gen Z, especially the role of AI in the back-end learning process, namely to verify and validate understanding. This paper suggests that AI apps should be controlled if used in the front-end learning process, especially at the exploration stage, to improve CT skills. Without controlling the AI apps, they can reduce learners' ability to explore a topic according to their creativity and criticality.
Combined Waste Assessment Model and Fuzzy-FMEA in Lean Six Sigma for Generating Waste Reduction Strategy: A Proposed Model
Authors: Basuki Demas Emirbuwono , Cahyo Winda Nur , Handayani Dwi , Apriani Ratna Agil , Mukarim Rifki Nurul
Published: January 2024

Lean Six Sigma is a method that is quite effective in solving waste problems in the production process, but it is often not optimal because of the tools used in the DMAIC process. Therefore, we developed a proposed model by combining the Waste Assessment Model and Fuzzy-FMEA in Lean Six Sigma to reduce waste in the production process. The Waste Assessment Model was used at the defined stage to identify waste, while the Fuzzy-FMEA was used for priority waste risk analysis at the analysis stage. Based on the results of the Waste Assessment Model case study, defects were the most influential waste, with a percentage of 22.38%. At the analysis stage using Pareto diagrams, tearing was the dominant defect in the Nike Extreme. Based on calculations using the Fuzzy-FMEA method, the highest cause of defects was errors in processes or missed processes that caused the failure. Improvement was carried out at the improvement stage, and we found it necessary to carry out intensive and periodic control or supervision of the Nike Extreme production process. Based on these results, the proposed Lean Six Sigma model can be used to identify and reduce waste in the production process.
Representasi Gaya Hidup Masyarakat Kota Besar dalam Iklan Gojek versi “Ribet Nyari Parkir Kalo Nyetir, Sekarang Tinggal Nge-Gojek Aja!”
Authors: Octaviano Rifqi Athallah
Published: January 2024

Gaya hidup dapat mencerminkan eksistensi dunia modern dan dapat mempengaruhi perilaku individu serta masyarakat di dalamnya. Gaya hidup tidak dapat dilepaskan dari pengaruh modernitas yang umumnya banyak berkembang dalam masyarakat kota. Sebagai lingkungan besar yang kompleks, interaksi sosial dan perbedaan status beserta ekonomi masyarakat kota memunculkan kelahiran budaya populer yang dapat kembali mempengaruhi gaya hidup. Penelitian ini berfokus dalam melihat serta menganalisis representasi gaya hidup di kota besar melalui iklan aplikasi Gojek yang berjudul “Ribet Nyari Parkir Kalo Nyetir, Sekarang Tinggal Nge-Gojek Aja!”. Melalui iklan, budaya populer serta gaya hidup dikomunikasikan melalui tanda-tanda dalam bentuk visual yang banyak dikonsumsi. Oleh karena itu, penelitian ini menggunakan metode analisis tekstual dengan semiotika dari Roland Barthes untuk memahami tanda tersebut secara denotatif dan konotatif yang tercermin secara representasional dalam video iklan Gojek ini.
Inhibitory Effect of Adefovir and Lamivudine on the Initiation of Hepatitis B Virus Infection in Primary Tupaia Hepatocytes
Authors: Köck Josef , Baumert Thomas F. , Delaney William E. , Blum Hubert E. , von Weizsäcker Fritz
Published: November 2003

Adefovir dipivoxil and lamivudine are two safe and efficacious drugs licensed for the treatment of chronic hepatitis B virus (HBV) infection. Both drugs inhibit the viral polymerase, resulting in a profound suppression of virus production. Blocking the viral polymerase may also affect the initiation of HBV infection, because HBV virions harbor a partially double–stranded genome and productive infection requires completion of viral plus–strand DNA synthesis with subsequent formation of covalently closed circular DNA (cccDNA). To address this issue, we used primary hepatocytes from the tree shrew Tupaia belangeri that were recently shown to be susceptible to HBV infection. Treatment of cells with either drug partially inhibited initial HBV cccDNA formation. Adefovir was more effective than lamivudine, resulting in a 3–fold reduction of RNA synthesis and viral surface antigen production. However, prevention of initial cccDNA formation was incomplete even after combined treatment, whereas de novo synthesis of viral replicative intermediates was completely suppressed. A possible explanation for this observation is the genomic plus–strand gap of less than 200 bases in some virions, limiting the window for antiviral action. In conclusion, nucleos(t)ide analogues can target initial plus–strand DNA repair and reduce but not completely block HBV infection.
Impaired Irs–1/Pi3–Kinase Signaling in Patients With Hcv: A Mechanism for Increased Prevalence of Type 2 Diabetes
Authors: Aytug Serhat , Reich David , Sapiro Lawrence E. , Bernstein David , Begum Najma
Published: November 2003

Patients with hepatitis C virus (HCV) infection have a greater risk of developing type 2 diabetes mellitus. However, the mechanism of this association is unclear. In this study, we examined the potential defects in upstream insulin signaling pathways in liver specimens obtained from nonobese/nondiabetic subjects with HCV infection. Fasting liver biopsy specimens were obtained from 42 HCV–infected subjects and 10 non–HCV–infected subjects matched for age and body mass index. Liver tissues were exposed to insulin and examined for the contents and phosphorylation/activation status of the upstream insulin signaling molecules by immunoprecipitation and Western blot analysis. HCV infection resulted in a trend toward a 2–fold to 3–fold increase in insulin receptor (IR) and insulin receptor substrate (IRS)–1 contents when compared with non–HCV. In contrast, insulin–stimulated IRS–1 tyrosine phosphorylation was decreased by 2–fold in HCV–infected subjects compared with non–HCV–infected subjects (P < .05). The observed reductions in IRS–1 tyrosine phosphorylation were accompanied by a 3.4–fold decrease in IRS–1/p85 phosphatidylinositol 3–kinase (PI3–kinase) association and a 2.5–fold decrease in IRS–1–associated PI3–kinase enzymatic activity (P < .05 vs. non–HCV). This was accompanied by a marked reduction in insulin–stimulated Akt phosphorylation without any alterations in mitogen–activated protein kinase (MAPK) phosphorylation. Cellular contents of the hepatic p85 subunit of PI3–kinase were comparable between HCV–infected and non–HCV–infected subjects. In conclusion, we found that (1) HCV infection leads to a postreceptor defect in IRS–1 association with the IR and (2) insulin signaling defects in hepatic IRS–1 tyrosine phosphorylation and PI3–kinase association/activation may contribute to insulin resistance, which leads to the development of type 2 diabetes mellitus in patients with HCV infection.
Association of Genetic Variants of the Chemokine Receptor Ccr5 and Its Ligands, Rantes and Mcp–2, With Outcome of Hcv Infection
Authors: Hellier Simon , Frodsham Angela J. , Hennig Branwen J.W. , Klenerman Paul , Knapp Suzanne , Ramaley Patricia , Satsangi Jack , Wright Mark , Zhang Lyna , Thomas Howard C. , Thursz Mark , Hill Adrian V.S.
Published: November 2003

The effect of host genetic variation on the outcome of hepatitis C virus (HCV) infection and its treatment is poorly understood. The chemokine receptors CCR5, CCR2, and CCR3 and their ligands, RANTES, MCP–1, MCP–2, and MIP–1α, are involved in the immune responses and the selective recruitment of lymphocytes to the liver in HCV infection. We studied 20 polymorphisms within these genes and investigated their association with persistent carriage of HCV, severity of liver disease, hepatic inflammation, and response to treatment in a large European cohort. Significant associations were found between CCR5–Δ32 and reduced portal inflammation (P = .011, odds ratio [OR]: 2.3, 95% confidence interval [CI]: 1.09–4.84) and milder fibrosis (P = .015, OR: 1.97, 95% CI: 1.13–3.42). A promoter polymorphism at position -403 in the RANTES gene was associated with less severe portal inflammation (P = .004). An amino acid change in MCP2, Q46K, was associated with severity of fibrosis (P = .018, OR: 2.29, 95% CI: 1.14–4.58). In conclusion, our study suggests a possible role of the polymorphisms CCR5–Δ32, RANTES -403, and MCP–2 Q46K in the outcome of HCV infection.
Dna Methylation Controls the Responsiveness of Hepatoma Cells to Leukemia Inhibitory Factor
Authors: Blanchard Frédéric , Tracy Erin , Smith Joseph , Chattopadhyay Souvik , Wang Yanping , Held William A. , Baumann Heinz
Published: November 2003

The related members of the interleukin 6 (IL–6) family of cytokines, IL–6, leukemia inhibitory factor (LIF), and oncostatin M, act as major inflammatory mediators and induce the hepatic acute phase reaction. Normal parenchymal liver cells express the receptors for these cytokines, and these receptors activate, to a comparable level, the intracellular signaling through signal transducer and activator of transcription (STAT) proteins and extracellular–regulated kinase (ERK). In contrast, hepatoma cell lines show attenuated responsiveness to some of these cytokines that is correlated with lower expression of the corresponding ligand–binding receptor subunits. This study tests the hypothesis that the reduced expression of LIF receptor (LIFR) observed in hepatoma cells is mediated by altered DNA methylation. H–35 rat hepatoma cells that have a greatly reduced LIF responsiveness were treated with 5–aza–2′–deoxycytidine, an inhibitor of DNA methyltransferase. Surviving and proliferating cells showed reestablished expression of LIFR protein and function. Restriction landmark genomic scanning (RLGS) demonstrated genome–wide drug–induced alterations in DNA methylation status, with striking similarities in the demethylation pattern among independently derived clonal lines. Upon extended growth in the absence of 5–aza–2′–deoxycytidine, the cells exhibit partial reversion to pretreatment patterns. Demethylation and remethylation of the CpG island within the LIFR promoter that is active in normal liver cells correlate with increased and decreased usage of this promoter in H–35 cells. In conclusion, these results indicate that transformed liver cells frequently undergo epigenetic alterations that suppress LIFR gene expression and modify the responsiveness to this IL–6 type cytokine.
Humoral and Cardiac Effects of Tips in Cirrhotic Patients With Different “Effective” Blood Volume
Authors: Salerno Francesco , Cazzaniga Massimo , Pagnozzi Giovanni , Cirello Ilaria , Nicolini Antonio , Meregaglia Daniele , Burdick Larry
Published: November 2003

The aim of this study was to evaluate the cardiac effects of transjugular intrahepatic portosystemic shunts (TIPS) in cirrhotic patients with different effective blood volume. Two–dimensional echocardiography was performed before and 7 and 28 days after TIPS insertion in 7 cirrhotic patients with PRA <4 ng/mL/h (group A, normal effective blood volume) and 15 with PRA >4 ng/mL/h (group B, reduced effective blood volume). Before TIPS, most cirrhotic patients showed diastolic dysfunction as indicated by reduced early maximal ventricular filling velocity (E)/late filling velocity (A) ratio. Patients of group B differed from patients of group A because of smaller left ventricular volumes and stroke volume, indicating central underfilling. After TIPS insertion, portal decompression was associated with a significant increase of cardiac output (CO) and a decrease of peripheral resistances. The most important changes were recorded in patients of group B, who showed a significant increase of both the end–diastolic left ventricular volumes and the E/A ratio and a significant decrease of PRA. In conclusion, these results show that the hemodynamic effects of TIPS differ according to the pre–TIPS effective blood volume. Furthermore, TIPS improves the diastolic cardiac function of cirrhotic patients with effective hypovolemia. This result is likely due to a TIPS–related improvement of the fullness of central blood volume.
Separate Analysis of Asialoglycoprotein Receptors in the Right and Left Hepatic Lobes Using 99MTc–Gsa Spect
Authors: Sugahara Kazuhiko , Togashi Hitoshi , Takahashi Kazuei , Onodera Yuya , Sanjo Mai , Misawa Keiko , Suzuki Akihiko , Adachi Tohru , Ito Junitsu , Okumoto Kazuo , Hattori Etsuko , Takeda Tadashi , Watanabe Hisayoshi , Saito Koji , Saito Takafumi , Sugai Yukio , Kawata Sumio
Published: November 2003

The asialoglycoprotein receptor (ASGPR) is abundantly expressed on the sinusoidal surfaces of hepatocytes. We aimed to clarify the clinical significance of the regional distribution of ASGPRs in the human liver, especially in chronic viral hepatitis. Eighteen volunteers, 34 patients with chronic hepatitis, and 33 patients with cirrhosis (11/Child–Pugh A, 11/Child–Pugh B, 11/Child–Pugh C) were studied using a newly developed, conventional technetium–99m–diethylenetriaminepentaacetic acid–galactosyl human serum albumin (99mTc–GSA), single photon emission computed tomography (SPECT) method. Using Cantlie's line as a guide, ASGPR dynamics were analyzed separately in the right and left lobes, as well as in the whole liver, using novel indices (the liver uptake ratio [LUR] and the liver uptake density [LUD], which reflect the amount and density of ASGPRs in the liver, respectively). Mean LUR and LUD values for the whole liver and the right and left lobes decreased with increasing progression of chronic viral hepatitis. The LUR for the whole liver correlated well with parameters measuring the hepatic functional reserve and the platelet count. The right LUR correlated particularly well with conventional liver function tests, and comparison of the right LUD with histologic findings showed that it was a good indicator of periportal and/or bridging necrosis and fibrosis. In conclusion, our 99mTc–GSA SPECT method was clinically useful in evaluating regional hepatic function and the progression of chronic viral hepatitis using dynamic changes in ASGPRs.
Early Change in Bilirubin Levels Is An Important Prognostic Factor in Severe Alcoholic Hepatitis Treated With Prednisolone
Authors: Mathurin Philippe , Abdelnour Marcelle , Ramond Marie-José , Carbonell Nicolas , Fartoux Laetitia , Serfaty Lawrence , Valla Dominique , Poupon Raoul , Chaput Jean-Claude , Naveau Sylvie
Published: November 2003

Early identification of patients with severe (discriminant function ≥32) biopsy–proven alcoholic hepatitis (AH) who are not responding to corticosteroids would be clinically relevant. Our goal was to develop simple criteria that will help physicians to promptly identify nonresponders to corticosteroids. A total of 238 patients were included. We used 6 months survival as an end point because of the rule requiring 6 months for listing alcoholic patients for transplantation. Overall survival at 1 and 6 months was 85% ± 2.3% and 64.3% ± 3.3%, respectively. An early change in bilirubin levels (ECBL) at 7 days (defined as bilirubin level at 7 days lower than bilirubin level on the first day of treatment) was observed in 73% of patients. At 7 days, in patients with ECBL, bilirubin decreased (84 ± 75 μmol/L [4.94 ± 4.40 mg/dL]), whereas it increased in patients without ECBL (76.5 ± 77 μmol/L [4.50 ± 4.54 mg/dL], P < .0001). Ninety–five percent of patients with ECBL continued to have improved liver function during treatment. At 6 months, survival of patients with ECBL was significantly higher than that of patients without ECBL, 82.8% ± 3.3% versus 23% ± 5.8%, P < .0001. On multivariate analysis, ECBL, discriminant function and creatinine were independent prognostic variables, and ECBL had the most important prognostic value. In conclusion, ECBL is a very simple predictive factor for identifying nonresponders. A recommendation to discontinue corticosteroids after 7 days in patients without ECBL, suggested by our results, awaits additional confirmation.
Adefovir Dipivoxil Therapy for Lamivudine–Resistant Hepatitis B in Pre- and Post-Liver Transplantation Patients
Authors: Schiff Eugene R. , Lai Ching-Lung , Hadziyannis Stefanos , Neuhaus Peter , Terrault Norah , Colombo Massimo , Tillmann Hans L. , Samuel Didier , Zeuzem Stefan , Lilly Leslie , Rendina Maria , Villeneuve Jean-Pierre , Lama Nicole , James Craig , Wulfsohn Michael S. , Namini Hamid , Westland Christopher , Xiong Shelly , Choy Gavin S. , Van Doren Sally , Fry John , Brosgart Carol L.
Published: November 2003

Three–hundred and twenty–four patients were enrolled in an open–label, multicenter, international study in which pre– and post–liver transplantation (LT) patients with recurrent chronic hepatitis B (CHB) and evidence of lamivudine–resistant HBV were treated with adefovir dipivoxil 10 mg once daily. In the pre– and post–LT cohorts, 128 and 196 patients were treated for a median duration of 18.7 and 56.1 weeks, respectively. In patients who received 48 weeks of treatment, 81% of the pre–LT and 34% of the post–LT cohort achieved undetectable serum hepatitis B virus (HBV) DNA (Roche Amplicor MonitorTM polymerase chain reaction [PCR] assay lower limit of quantification [LLQ] < 400 copies/mL) with a median change in serum HBV DNA from baseline of -4.1 log10 and -4.3 log10 copies/mL, respectively. Serum alanine aminotransferase (ALT), albumin, bilirubin, and prothrombin time normalized in 76%, 81%, 50%, and 83% of pre–LT patients and 49%, 76%, 75%, and 20% of post–LT patients. The Child–Pugh–Turcotte (CPT) score improved in over 90% of patients in both cohorts. Genotypic analysis of 122 HBV baseline samples revealed that 98% of these patients had lamivudine–resistant mutant HBV. No adefovir resistance mutations were identified in patients after 48 weeks of therapy. One–year survival was 84% for pre–LT and 93% for post–LT patients (Kaplan–Meier analysis). Treatment–related adverse effects associated with adefovir dipivoxil in this setting were primarily mild to moderate in severity. In conclusion, 48 weeks of adefovir dipivoxil resulted in significant improvements in virologic, biochemical, and clinical parameters in CHB patients pre– and post–LT with lamivudine–resistant HBV.
Social Engineering and the Contradictions of Modernization in Khuzestan's Company Towns: A Look at Abadan and Masjed-Soleyman
Authors: Ehsani Kaveh
Published: November 2003

After the discovery of oil in Masjed-Soleyman by employees of the D'Arcy Concession in 1908, the Anglo Persian Oil Company (APOC) was incorporated in London. The oil cities of Abadan, Masjed-Soleyman, and at least seven other sister towns designed and constructed by the APOC in the first quarter of the twentieth century in Khuzestan, were the first modern and industrial towns in Iran and the Middle East. This essay studies Abadan and Masjed-Soleyman – company towns with, on the one hand, a modern and authoritarian structure and organization, and on the other hand, thanks to the heterogeneity and energy of their population, as well as the forbidding scale the cities had reached despite the company's wishes, a conditional modernity. The result of these contradictions were cities and urban cultures that were energetic and dynamic, but also eclectic and hybrid.
Organised Protestant Missions to Chinese Immigrants in Canada, 1885–1923
Authors: WANG JIWU
Published: November 2003

During a period of almost forty years, major Protestant denominations in Canada consolidated their scattered and individual Chinese mission activities into centralised institutions. However, the missions did not gain significant success in the mission field. Church leaders and missionaries often attributed this to a chronic lack of financial and human resources. But the real reason was the anti-Chinese sentiment that always cast a shadow over the missions. The rise of nationalism in the Chinese community at the turn of the twentieth century also had a negative effect on the mission.
DISCUSSION: HAMPTON ON FREE RIDING
Authors: Sollars Gordon G.
Published: November 2003

Jean Hampton has argued that an important case of the free-rider problem has the structure of a battle-of-the-sexes game, rather than the Prisoner's Dilemma, as is often assumed. This case occurs when the collective good to be produced is a ‘step’ or ‘lumpy’ good, one that is produced in a single production step. Battle of the Sexes is a coordination game, with stronger equilibria than games such as the Prisoner's Dilemma or Chicken. Hampton argues that, because of this difference, there is good reason to think that players facing a battle-of-the-sexes game can more easily reach mutually desirable outcomes than players facing these other games. An examination of Hampton's argument, however, shows that she has failed to specify a condition that would clearly distinguish her examples of battle-of-the-sexes games from chicken games. Consequently, Hampton's claim that free riding in the provision of step goods is less tempting than other analyses have suggested because of the presence of coordination equilibria is incorrect as it stands.
Marine snow latitudinal distribution in the equatorial Pacific along 180°
Authors: Gorsky Gabriel , Le Borgne Robert , Picheral Marc , Stemmann Lars
Published: November 2003

Marine snow (MS) distribution from the surface to 1000 m depth was determined in the equatorial Pacific using the underwater video profiler during the Etude du Broutage en Zone Equatoriale cruise in fall 1996. The latitudinal transect was carried out at 17 stations along the 180° meridian from 8°S to 8°N during a cold phase of El Niño‐Southern Oscillation. Higher MS concentrations were found below the equatorial zone than poleward. At the equator the estimated integrated MS carbon m−2 in the upper kilometer was 5.7 g m−2, while both southward and northward (between 1° and 8°) the mean integrated MS carbon was about 2.7 g. m−2. In the upper 50 m the MS carbon was twofold lower than the combined carbon of autotrophic and heterotrophic protists and four times lower than the mesozooplankton carbon biomass, both measured concurrently during the cruise. Different water bodies had different MS content. The highest concentrations were found in the South Equatorial Current, the South Equatorial Counter Current, and the North Equatorial Countercurrent. Tropical waters at the south in the South Subsurface Countercurrents and the warm northern superficial waters had the lowest MS biomass. Mechanistically, a latitudinal “conveyor belt”, a poleward divergence of upwelled waters that return to the equator after being downwelled at north and south convergent zones, may partially explain the vertical distribution of particulate matter observed during the studied period.
Can an isotropic plasma pressure distribution be in force balance with the T96 model field?
Authors: Zaharia Sorin , Cheng C. Z.
Published: November 2003

In this paper we investigate how close the gradient force of an isotropic pressure distribution P can be in force balance with the magnetic (Lorentz) force in the T96 empirical model. The study leads to the conclusion that no isotropic pressure can be found in exact force balance with the magnetic field of the quiet time T96 model. The conclusion is derived from several analyses: (1) computing the loop integral of J × B from the model along a closed contour in the equatorial plane (the integral should vanish if J × B = ∇P); (2) obtaining one‐dimensional profiles for P on the Sun‐Earth axis by integrating ∇P = J × B and comparing them with observations; and (3) decomposing J × B into gradient‐free and curl‐free terms (the former term would be zero in an exact equilibrium) and subsequently computing the two terms by solving a Poisson‐like equation with constraints. Possible physical reasons for our finding that no P exists such that J × B = ∇P include small mass flows as well as nonisotropic (and possibly even nongyrotropic) terms in the magnetospheric pressure tensor. While the lack of exact force balance with isotropic P will probably be not too serious for many situations, for some physical applications, such as the computation of Birkeland currents using the Vasyliunas relation, care must be exercised if one uses the model field in conjunction with isotropic pressure. Finally, we discuss possible ways of computing magnetospheric configurations in exact force balance with isotropic P by using empirical model fields as a starting point.
A study of the onset of melt over the Arctic Ocean in RADARSAT synthetic aperture radar data
Authors: Kwok R. , Cunningham G. F. , Nghiem S. V.
Published: November 2003

The regional melt onset signal of Lagrangian elements of Arctic sea ice in RADARSAT synthetic aperture radar (SAR) data during the spring of 1998 is examined. The melt signal is clearly detectable not only in backscatter changes over multiyear ice but also first‐year ice and mixtures of these ice types. This allows a more complete mapping of the progression of melt over the sea ice cover. For the spring of 1998 the onset dates range between 10 May and 29 June. The spatial pattern of melt onset is characterized by sharp boundaries delineating distinct regions with relatively uniform onset dates. This pattern appears to be associated with moisture and warm air brought in by a low‐pressure trough and the timing of a rain event reported at the Surface Heat Budget of the Arctic Ocean (SHEBA) camp. Measurements from the SHEBA camp show good correspondence between the timing of melt in SAR imagery and the onset of albedo drop off associated with the beginning of summer. Onset dates are compared with the timing of the zero crossing of the temperature records from drifting buoys and the onset dates derived from satellite passive microwave brightness temperature fields. The timing of our estimates is within 1–2 days of the zero crossing of the buoy temperature records. Onset dates derived from passive microwave observations appear to be biased toward a later stage of melt. Comparison with results derived from a SAR data set from the spring of 1992 show that the onset of melt in 1998, derived from RADARSAT, in the Beaufort Sea occurred 2 weeks earlier.
Vertical profiles of activated ClO and ozone loss in the Arctic vortex in January and March 2000: In situ observations and model simulations
Authors: Vogel Bärbel , Grooß Jens‐Uwe , Müller Rolf , Deshler Terry , Karhu Juha , McKenna Daniel S. , Müller Melanie , Toohey Darin , Toon Geoffrey C. , Stroh Fred
Published: November 2003

In situ observations of ClO mixing ratios obtained from a balloonborne instrument launched in Kiruna on 27 January 2000 and on 1 March 2000 are presented. ClO mixing ratios and quasi‐simultaneously observed ozone loss are compared to model simulations performed with the Chemical Lagrangian Model of the Stratosphere (CLaMS). ClO mixing ratios are simulated initializing the model simulations for early winter conditions. Sensitivity studies are performed to explore the impact of the surface area of the background aerosol, of denitrification, and of the recently reported kinetics of the ClO self‐reaction [Bloss et al., 2001] on simulated ClO. For 27 January 2000, model simulations agree with rate constants reported by Bloss et al. [2001], whereas for 1 March 2000 simulations employing rate constants reported by Bloss et al. [2001] and by Sander et al. [2000] reproduce the ClO measurements. The impact of uncertainties arising from accumulated errors along the calculated backward trajectories and uncertainties within temperatures derived from the UK Met Office are also studied. For both flights, simulated ClO show a good overall agreement with measured ClO within uncertainties arising from accumulated errors along air parcel histories. We find a layer of low ClO mixing ratios < 100 pptv between 600 and 620 K for the flight on 27 January 2000 and between 525 and 550 K on 1 March 2000. For this layer, measured ClO is substantially lower than simulated ClO. Potential causes are discussed, but the discrepancy remains unexplained at present. Furthermore, for 1 March 2000, an overall agreement is found between model simulations and measurements by the HALOE instrument of HCl and NOx (=NO + NO2) for all altitudes considered. We conclude that denitrification occurred up to a potential temperature of ≈550 K (≈24 km altitude) on 1 March 2000. Finally, model simulations show that between late January and 1 March, a significant ozone loss of about 0.8–1.8 ppmv is derived between 425 and 490 K of potential temperature in agreement with measured ozone loss and correlated with the enhanced ClO. For 1 March 2000, 77 ± 10 DU is obtained as an estimate of the loss in column ozone.
Influence of variations in NAO and SO on air temperature over the northern Tibetan Plateau as recorded by δ18O in the Malan ice core
Authors: Ninglian Wang , Thompson L. G. , Davis M. E. , Mosley‐Thompson E. , Tandong Yao , Jianchen Pu
Published: November 2003

An isotopic (δ18O) enrichment trend from 1887 to 1998 recorded in the Malan ice core from the northern Tibetan Plateau indicates that temperatures there have warmed in the past century. Statistical analyses suggest that the annual δ18O in this ice core largely reflects air temperature variations in the warm season. Statistically significant modest to weak correlations were found between the annual δ18O and the North Atlantic Oscillation (NAO) index from May through October and the Southern Oscillation (SO) index from August through November, respectively. A multivariate linear regression shows that when combined, the NAO and SO account for 55% of the total variance in δ18O over the past century. Moreover, the correlations between δ18O and the NAO and the SO vary over the study period, as might be expected due to changes in the strength and amplitude of the NAO and SO over the past century.
Internal tide scattering at the Line Islands Ridge
Authors: Johnston T. M. Shaun , Merrifield Mark A. , Holloway Peter E.
Published: November 2003

Scattering of the M2 mode one internal tide from the Line Islands Ridge is examined with a primitive equation numerical model. Model runs with baroclinic and barotropic forcing are performed to distinguish scattered from locally generated internal tides. TPXO.5 tidal model sea surface elevations provide barotropic forcing, while for the run with baroclinic forcing a mode one M2 energy flux of 1000 W m−1 is used to represent energy fluxes emanating from the Hawaiian Ridge. Scattering redistributes more energy flux from mode one than is locally generated in mode one. For the higher modes, scattering and generation contribute equally in terms of the overall energy flux. Spatial and modal distributions of energy density and flux show internal tide scattering dominates at Hutchinson Seamount, while higher modes are generated locally at Sculpin Ridge. Hutchinson Seamount's slopes are steeper over a greater continuous area than Sculpin Ridge. Scattered energy is found downstream of the steepest topographies, similar to simulations with idealized Gaussian ridges. At the Line Islands Ridge, 37% of the incident mode one energy flux is lost because of scattering into modes 2–5 (19%), dissipation by the model's turbulence parameterization (15%), and nonlinear transfer to the M4 internal tide (3%). Two TOPEX ground tracks pass through the model domain roughly normal to the ridge topography and confirm the general features of the modal and spatial distribution found in the model. In the topographically rough western Pacific, internal tide scattering may be a significant source of energy for mixing away from topography.
Cation Structures in Bis(2-Guanidino-benzimidazole)metal(II) Complexes: Crystal and Molecular Structure of the Copper(II) Perchlorate Adduct
Authors: Arablo Naser , Torabi S. Ali Asghar , Morsali Ali , Skelton Brian W. , White Allan H.
Published: November 2003

Following previous studies of [M(gbH)2](NO3)2 (M = Ni(II), Zn(II), gbH = 2-guanidinobenzimidazole) a low temperature single-crystal X-ray study of [Cu(gbH)2](ClO4)2·H2O enables a comparison of the impact of the different electron configurations of these divalent metals on the overall cation geometries.
8-Allyldihydroberberine as an Alternative Precursor for the Synthesis of 13-Substituted Berberine Derivatives
Authors: Bremner John B. , Samosorn Siritron
Published: November 2003

An alternative route to 13-substituted derivatives of the biologically active alkaloid berberine has been developed based on the key synthetic precursor, 8-allyldihydroberberine.
Approaches to Cyclopropa-Fused Quinones. The Synthesis and Photolysis of Some 4,9-Disubstituted 3,3-Dimethyl-3H-benz[f]indazoles
Authors: Collis Gavin E. , Wege Dieter
Published: November 2003

Addition of 2-diazopropane to 1,4-naphthoquinone at low temperature, followed by in situ enolization and acetylation or silylation gave 3,3-dimethyl-1H-benz[f]indazol-4,9-diyl diacetate and 3,3-dimethyl-9-(t-butyl-dimethylsilyloxy)-1H-benz[f]indazol-4-ol, respectively. Functional group manipulation of the latter compound provided a number of other 4,9-disubstituted 3,3-dimethyl-3H-benz[f]indazoles. Irradiation of the diacetate led to clean extrusion of nitrogen to give the naphtho[b]cycloproparene and an alkene. Attempts to elaborate the cycloproparene into the derived cyclopropanaphthoquinone were unsuccessful. Of the other 4,9-disubstituted 3,3-dimethyl-3H-benz[f]indazoles examined, only the compound possessing an acetoxy group at C9 was photoactive, and afforded the expected cycloproparene and alkene. Compounds bearing a hydroxy or alkoxy group at C9 were photochemically inert.
Chiral Resolution of Hexaamine Cobalt(III) Cages: Substituent Effects on Chiral Discrimination
Authors: Bernhardt Paul V. , Dyahningtyas Tri Erny , Harrowfield Jack M. , Kim Jee-Young , Kim Yang , Rukmini Elisabeth
Published: November 2003

Chiral resolution of the cobalt cage complexes [Co(diNOsar)]3+ and [Co(diAMsarH2)]5+ have been achieved by selective crystallization with the anion bis-μ-(R), (R)-tartratodiantimonate(III) ([Sb2(R,R-tart)2]2–) and also by column chromatography with Na2[Sb2(R,R-tart)2] as eluent. The X-ray crystal structures of Λ-[Co(diNOsar)][Sb2(R,R-tart)2]Cl . 7 H2O and Δ-[Co(diAMsarH2)][Sb2(R,R-tart)2]2Cl . 14 H2O are reported, which reveal an unexpected reversal of chiral discrimination when the cage substituent is changed from nitro (Λ-enantiomer) to ammonio Δ-enantiomer) and shows that the ammonio-substituted cage is capable of forming a three-point hydrogen-bonding interaction with each complex anion, whereas the nitro analogue can only form two hydrogen bonds with each [Sb2(R,R-tart)2]2– anion. During cation exchange chromatography of the racemic cobalt cage complexes with Na2[Sb2(R,R-tart)2] as eluent, Λ-[Co(diNOsar)]3+ elutes first, which implies a tighter ion pairing interaction than for the Δ-enantiomer. On the other hand, Δ-[Co(diAMsarH2)]5+ elutes first during chromatography under identical conditions, which is also consistent with a preferred outer-sphere complex formed between Δ-[Co(diAMsarH2)]5+ and [Sb2(R,R-tart)2]2– relative to Λ-[Co(diAMsarH2)]5+ and [Sb2(R,R-tart)2]2–.
A Two-Dimensional Layered Cadmium Polymer Featuring Cd4(μ-O)4 Cores and Fluorescent Emission
Authors: Yang Jin-Hua , Li Wei , Zheng Shao-Liang , Huang Zhen-Li , Chen Xiao-Ming
Published: November 2003

A cadmium coordination complex featuring novel Cd4(μ-O)4 cores, [Cd2(Hbna)(opy)(H2O)2] (1) (H4bna=2,2′-dihydroxy-[1,1′]-binaphthalene-3,3′-dicarboxylate acid; Hopy=1H-pyridine-2-one), has been hydrothermally synthesized and characterized. The Hbna ligand here acts in an unprecedented chelating/tridentate coordination mode for two carboxy groups with an additional μ-O-bridging coordination mode for the ortho-hydroxy oxygen atom. A study of the physical properties of solid (1) at room temperature demonstrates that it exhibits a moderately strong fluorescent emission in the blue-green region (about 538 nm), which can be assigned to LMCT emission.
Foliar applications of phosphate increase the yield of essential oil inmenthol mint (Mentha arvensis)
Authors: Ram M. , Singh R. , Ram D. , Sangwan R. S.
Published: November 2003

Field experiments were conducted at Lucknow, India, to study the effect of foliar application of orthophosphoric acid and diammonium phosphate filtrate on the biosynthesis and yield of essential oil in transplanted menthol mint: a foliage rich and vegetatively harvested crop. A foliar spray of 10% diammonium phosphate filtrate on the plants of menthol mint enhanced the biosynthesis of essential oil in the leaves to the extent of 15.6–18.7% over the control. A spray of 0.1% orthophosphoric acid gave an increase in the range 8.0–9.4%. When different varieties of menthol mint were sprayed with 10% diammonium phosphate filtrate, the variety Kosi exhibited 13, 78.3 and 66% higher essential oil yield over the varieties Himalaya, Hariti and Kalka, respectively. At the same concentration of spray, the variety Kosi enhanced the essential oil yield by 60% compared with that of the control. The early transplanted crop (18 March) was found to be good in terms of higher essential oil production by about 31% than the later transplanted crop (31 March). It is recommended that in order to get a high essential oil yield from a transplanted mint crop, a foliar spray of 10% diammonium phosphate filtrate should be applied twice, first in the second week of April and second in the first week of June. The optimum time to transplant mint plantlets in the field is the third week of March. A putative working metabolic model of the phosphate effect on biosynthesis of essential oil in volatile plants has been proposed.
Magnetic resonance imaging of water movement through asparagus
Authors: Heyes Julian A. , Clark Christopher J.
Published: November 2003

Asparagus spears are rapidly growing structures supplied with abundant vascular bundles. After extended periods of water loss, the stem surface becomes flaccid over a core of turgid tissue. We have used magnetic resonance imaging (MRI) coupled with a paramagnetic contrast reagent (Mn2+) to visualise water and ion movement within spear tissues. Using this technique we estimated the rate of water flow in the xylem and lateral movement out of the xylem into the surrounding tissues. Longitudinal flow rates of at least 3.7 mm min–1 and lateral diffusion rates of at least 17 μm min–1 were recorded. The outer parenchyma was difficult to label with vascular-supplied Mn2+, suggesting the presence of an apoplastic barrier. Stem shrinkage was greater in the outer parenchyma than in the inner cortex and pith parenchyma. Feeding the cut spear with 70 mM sucrose reduced the rate of lateral movement of Mn2+. The MRI technique highlighted differences in transport rates between adjacent vascular bundles and identified structural features with a resolution of 78 μm. This non-invasive technique is useful both for observing details of the transport paths in living tissue and for setting minimal estimates of transport rates.
Non-self recognition, transcriptional reprogramming, and secondary metabolite accumulation during plant/pathogen interactions
Authors: Hahlbrock Klaus , Bednarek Pawel , Ciolkowski Ingo , Hamberger Björn , Heise Andreas , Liedgens Hiltrud , Logemann Elke , Nürnberger Thorsten , Schmelzer Elmon , Somssich Imre E. , Tan Jianwen
Published: November 2003

Disease resistance of plants involves two distinct forms of chemical communication with the pathogen: recognition and defense. Both are essential components of a highly complex, multifaceted defense response, which begins with non-self recognition through the perception of pathogen-derived signal molecules and results in the production, inter alia, of antibiotically active compounds (phytoalexins) and cell wall-reinforcing material around the infection site. To elucidate the molecular details and the genomic basis of the underlying chains of events, we used two different experimental systems: suspension-cultured cells of
Petroselinum crispum
(parsley) and wild-type as well as mutant plants of
Arabidopsis thaliana
. Particular emphasis was placed on the structural and functional identification of signal and defense molecules, and on the mechanisms of signal perception, intracellular signal transduction and transcriptional reprogramming, including the structural and functional characterization of the responsible cis-acting gene promoter elements and transacting regulatory proteins. Comparing
P. crispum
and
A. thaliana
allows us to distinguish species-specific defense mechanisms from more universal responses, and furthermore provides general insights into the nature of the interactions. Despite the complexity of the pathogen defense response, it is experimentally tractable, and knowledge gained so far has opened up a new realm of gene technology-assisted strategies for resistance breeding of crop plants.
Influence of topology on bacterial social interaction
Authors: Park Sungsu , Wolanin Peter M. , Yuzbashyan Emil A. , Lin Hai , Darnton Nicholas C. , Stock Jeffry B. , Silberzan Pascal , Austin Robert
Published: November 2003

The environmental topology of complex structures is used by
Escherichia coli
to create traveling waves of high cell density, a prelude to quorum sensing. When cells are grown to a moderate density within a confining microenvironment, these traveling waves of cell density allow the cells to find and collapse into confining topologies, which are unstable to population fluctuations above a critical threshold. This was first observed in mazes designed to mimic complex environments, then more clearly in a simpler geometry consisting of a large open area surrounding a square (250 × 250 μm) with a narrow opening of 10–30 μm. Our results thus show that under nutrient-deprived conditions bacteria search out each other in a collective manner and that the bacteria can dynamically confine themselves to highly enclosed spaces.