bluuebunny/crossref_metadata_2025 huggingface dataset:
An Evaluation of Digital Addressing System Implementation in Ghana
Authors: Kubuga Kennedy Kumangkem , Ofori Philomina Pomaah , Abiam Solomon , Ayoung Daniel Azerikatoa , Asaamoning Godwin
Published: February 2024

Purpose: The research reviews the implementation of Ghana’s Digital Addressing System. Nearly six years into implementation and without an outward appearance of the meeting of the announced goals of the project, the research sets out to find out the likelihood of success or failure of the project and suggest remedial measures.

Relevance: The implementation of digital addressing in Ghana holds and demonstrates promise for benefits relative to transportation, courier services, taxation, property ownership and title, among others. For policy makers, the findings of this work give direct pointers to what needs to be done to keep the concept useful. For researchers, the work has only opened the doors for further academic and technical introspection into digital addressing and its nuances especially in Ghana.

Methods: Using a variety of quantitative and qualitative techniques the study assessed the implementation of the policy employing interviews, surveys, workshops and group discussion. It hinged on the Design-Reality Gap (DRG) model to identify the issues of interest with Ghana's digital addressing systems.

Findings: We found out that the attempts, although well intended, fall short in several best practice aspects. The research found it difficult to confidently showcase any immediate successes arising out of the implementation of the Ghana Post GPS App and System and proceeds to point out specific areas in need of attention if Ghana’s Digital Addressing efforts are to meet the presumptive goals.

Conclusion: The Digital Addressing System might be a partial failure unless action is taken to close design-reality gaps.
Influence of Drip Fertigation and Foliar Spray of Boron on Yield and Nutrient Uptake by Cucumber cv. Himangi
Authors: Giri Jaya , Ghawade S. M. , Panchbhai D. M. , Nagre P. K. , Kadu P. R. , Deshmukh M. M.
Published: February 2024

The effect of fertigation  and foliar application of boron on yield, uptake of nutrients and nutrient use efficiency by  cucumber Cv. Himangi was studied during two consecutive years 2018-19 and 2019-20. An experiment was carried out in open field conditions with five fertigation levels viz., 100 % RDF through soil, 120 %, 100 %, 80 %  and 60 % RDF through fertigation in ten equal splits at 10 days interval along with three levels of foliar application of boron viz. 0.0, 0.1, and 0.2 per cent concentration at 30, 45 and 60 DAS to determine suitable fertigation and foliar spray of boron dose for cucumber cultivation. The experiment was consisting of fifteen treatment combinations of recommended doses of water soluble fertilizers, comprising of five levels of fertigation.   The results indicated that, yield, nutrient uptake and nutrient use efficiency of nitrogen, phosphorus and potassium under study were significantly influenced by various fertigation and boron levels. On the basis of pooled data, it was observed that, among various treatment combinations, minimum  male : female sex ratio (1:4),  maximum average weight of fruit (239.88 g), yield per vine ( 2.44 kg), yield ( 228.37 q/ha), uptake of nitrogen by shoot, ( 13.03  kg/ha), ( 81.62 kg/ha) by fruit and (94.01 kg/ha) by whole cucumber vine, maximum uptake of phosphorus by shoot (3.62 kg/ha), (21.52  kg/ha) by fruit and ( 25.13 kg/ha) by whole cucumber vine and the maximum uptake of potassium by shoot ( 14.05   kg/ha), by fruit (101.45  kg/ha) and ( 115.20  kg/ha) by whole cucumber vine, B:C ratio (2.99) and minimum (27.73, 25.71 and 17.2, 16.85 and 55.28, 50.28 %, respectively) nutrient use efficiency of NPK were recorded with the application of 120 % RDF through fertigation due to nutrient losses through leaching, devolatilization. While, maximum (36.70, 34.70 and 25.38, 21.90 and 65.81, 63.43 respectively)  nutrient use efficiency of NPK was recorded with the application of 60 % RDF through fertigation. The maximum (22.59, 20.61 and 6.99, 7.70 and 27.30, 30.47 %, respectively) nutrient use efficiency with foliar application of boron at concentration of 0.2  per cent and minimum (3.60, 3.44 and 0.56, 0.52 and 3.72, 4.05 %, respectively) nutrient use efficiency with foliar application of boron at concentration of 0.1  per cent.
Investigation of the Presence of Bovine Papillomavirus in Blood Leukocytes of Cattle in West Mediterranean of Turkey
Authors: Taşatan Abdürrezzak , Kale Mehmet
Published: February 2024

One hundred Holstein cattle, varying in age from one to ten years, who had warts on different parts of its bodies and had previously had Bovine papillomavirus (BPV) typing had blood samples taken from them from various managements in Burdur-Center and its surroundings. DNA was extracted from leukocytes using the DNeasy Blood & Tissue Kit (Qiagen, Germany). RT-PCR test was performed using consensus and type-specific primers for the detection of BPV types. As a result of the study, RT-PCR test and consensus primers were not detected in blood leukocyte samples. Through the use of type-specific primers in an RT-PCR assay, the viral genome components of BPV-10 (56), BPV-11 (1), BPV-10+BPV-11 (2), BPV-10+BPV-12, and BPV-10+BPV-14 (2) were detected in these samples. BPV-12 was detected for the first time in blood leucocytes. In blood samples taken from animals classified according to the anatomical regions where the warts are located the highest BPV positivity (22,2%) was detected in animals with warts on the teats. Also, the most BPV-10 type was determined in the blood samples of animals with wart lesions on the teat and lobes. When the distribution of BPV PCR positive samples according to age groups was made, BPV PCR positive was found mostly in the between 1 and 47 month age group (71,4%). It was determined that the prevalence of BPV was high in the between 1 and 47 age group, while the rates of 48-83 months and later decreased with increasing age. In this investigation, it was found that BPV type 10 had been prevalent in blood leukocyte samples from cattle with warts in various areas of the body and with variable macroscopic appearance.
Assessment of Microbial, Physicochemical and Shelf-life of Sugarcane Jaggery Stored in Various Types of Packaging Materials
Authors: Rana Huma , Garg Amar Prakash , Jain Sourabh
Published: February 2024

The main problems associated with Jaggery storage are liquefaction and deterioration of properties. When compared to fresh Jaggery, the packaging using various packing materials showed that there was a marked increase in moisture (15–22%) in the Jaggery packed in HDPE, but no discernible change in the percentage of moisture in the Jaggery stored in an aluminium pouch and LDPE environment. After six months of storage, Jaggery kept in glass jars and HDPE began to degrade, but Jaggery packed in aluminium pouches maintained levels of sucrose, moisture, reducing sugars, titratable acidity, pore space, and total microbial count comparable to fresh Jaggery at room temperature, and it continued to be significantly improved overall. The hardness of the Jaggery, which led to its lower acceptability, proved to be its main drawback. However, the physico-chemical characteristics and shelf life of the Jaggery under aluminium pouch and LDPE were comparable with fresh Jaggery samples.

Objectives: The Jaggery industry is one of the largest and oldest in India, and the region in the north is known as the "sugar belt." However, small farmers face significant challenges in storing their Jaggery, which forces them to sell their product at a reduced price during the sugarcane season because it spoils quickly during rainy seasons. The goal of the current study was to evaluate the microbial, physicochemical, and shelf life of sugarcane Jaggery stored in various types of packaging material at room temperature. This was done to determine the impact of different packing materials with preserved properties comparable to fresh Jaggery, as the traditional method of storing Jaggery in villages reduces the product's market value and acceptability by causing microbial spoilage and bad odour.

Methodology: In April 2022, Jaggery samples were made using sugarcane juice from four certified genotypes (Co 0237, Co 0238, CoS 767, and CoJ 64). The samples were then packaged in glass jars (GJ), aluminium pouches (AP), and low- and high-density polythene (LDPE) bags. After being stored for six months, the samples were examined for physicochemical, microbiological, and general acceptability characteristics. Using potato dextrose agar (PDA) and nutritional agar (NAM) medium, microbial counts for bacteria, mould, and yeasts were assessed.

Results and Conclusions: The traditional way of storage was compared with future storage ways with improved preservation of properties with an eye on better trade practices. It was found that the Jaggery packed in aluminium pouch showed better preserved properties comparable to fresh for sale in the market.
Growth, Yield Attributes, Yield and Economics of Mustard (Brassica Juncea L.) as Affected by Different Varieties and Spacing
Authors: Kumar Mukesh , Tiwari Dhananjay
Published: February 2024

A field experiment was conducted at Agricultural Research Farm, Narayan Institute of Agricultural Sciences, Gopal Narayan Singh University, Jamuhar, Sasaram, Rohtas, (Bihar) during the Rabi season of 2022-2023 to access the effect of different varieties and spacing on growth and yield of mustard. Treatment consisted of three varieties RH- 404, DRMR-1165-40 and NRCM-101 and three spacing viz. 30×10 cm, 40×10 cm and 50×10 cm. Present Experiment was conducted under randomized block design with three replications. The result of experiment showed that growth viz, plant height and dry weight and yield attributes viz., number of seeds/siliqua, biological yield (Kg/ha) and economics viz., cost of cultivation (Rs/ha), gross return (Rs/ha), net return (Rs/ha) and B:C ratio and yield were significantly affected due to different varieties and spacing. The maximum plant height (165.72 cm), dry weight (35.32 g/plant), number of seeds/siliqua (15.97), gross return (124623.3 Rs/ha), net return (74004.5 Rs/ha) and B:C ratio of (1.48) was found in treatment combination of NRCM-101 + 40 cm × 10 cm. However treatment combination of DRMR-1165-40 + 30 cm × 10 cm recorded maximum biological yield (6665.37 kg/ha).
Evaluation of CI Engine Performance Using Compression Ratio for Palm Oil Biodiesel
Authors: Gajera M. N. , Lakhani A. L. , Faldu Dhruvkumar J. , Mehta T. D.
Published: February 2024

The experiment explores vegetable oils as potential future fuels for internal combustion engines, particularly compression ignition engines designed for diesel. However, these oils have distinct properties from diesel, requiring modifications for direct use. Integration approaches include adjusting oil properties or adapting engines. Commonly, transesterification aligns oil properties, but using biodiesel often affects engine performance. In this study palm oil biodiesel as a diesel substitute, evaluating engine performance and emissions. In a short-term test, engine performance and emission traits by employing biodiesel compression ratio of 12:1, 14:1 and 18:1 with diesel at full load. Findings indicated that 14:1 and 18:1 exhibited 1.01 % and 1.02 % higher brake power than pure diesel. Volumetric efficiency percentages were 82.33 for 14:1, 82.36 for 18:1, and 82.30 for 12:1. Notably, 14:1 and 18:1 showed 5.44% and 10.90 % increased brake thermal efficiency compared to diesel. Interestingly, 14:1 and 18:1 displayed 2.35 % and 2.61 % higher mechanical efficiency than diesel. The exhaust gas temperature was notably decreased in 12:1 to 18:1 compression ratio.  Nitric oxide concentrations were 65.07 ppm for 12:1, 124.44 ppm for 14:1, and 126.48 ppm for 18:1. Carbon dioxide levels increased by 9.79 % for 14:1 and 62.47 % for 18:1 relative to diesel. Carbon monoxide concentrations were 0.07 % for 14:1 and 0.05% for 18:1, in contrast to diesel's 0.12%.
Trends in Addiction to Psychoactive Substances Among Homeless People in Colombia Using Artificial Intelligence
Authors: Ordoñez Hugo , Timarán-Pereira Ricardo , González-Sanabria Juan-Sebastián
Published: February 2024

Introduction: Currently, homelessness should not be seen as just another problem, but as a reality of inequality and the absence of social justice. In this sense, homeless people are subjected to social disengagement, lack of job opportunities or the instability of these, insecurity circumstances, these aspects being one of the causes associated with the consumption or addiction to psychoactive substances. Data: To define the proposed approach, data from the Census of Street Inhabitants - CHC- 2021 of the National Administrative Department of Statistics (DANE), which contains 19,375 records and 25 columns, were used. Methodology: This article presents an artificial intelligence approach that implements a model based on machine learning algorithms for identifying addiction trends to psychoactive substances in street dwellers in Colombia. Conclusions: Based on the results obtained, it is evident that the approach can serve as a support for decision making by municipal administrations in the definition of social public policies for the street-dwelling population in Colombia.
Solubility of carbon dioxide in aqueous piperazine solutions
Authors: Derks P. W. J. , Dijkstra H. B. S. , Hogendoorn J. A. , Versteeg G. F.
Published: May 2005

In the present work, new experimental data are presented on the solubility of carbon dioxide in aqueous piperazine solutions, for concentrations of 0.2 and 0.6 molar piperazine and temperatures of 25, 40, and 70°C respectively. The present data, and other data available in the literature, were correlated using a model based on the electrolyte equation of state (EoS), as originally proposed by Fürst and Renon. The final model derived, containing only seven adjustable (ionic) parameters, was able to describe the available experimental solubility data (>150 data points for total and/or CO2 partial pressure) with an average deviation of 16%. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Inhibitors of Protein Tyrosine Phosphatases: Next‐Generation Drugs?
Authors: Bialy Laurent , Waldmann Herbert
Published: May 2005

The protein tyrosine phosphatases (PTPs) constitute a family of closely related key regulatory enzymes that dephosphorylate phosphotyrosine residues in their protein substrates. Malfunctions in PTP activity are linked to various diseases, ranging from cancer to neurological disorders and diabetes. Consequently, PTPs have emerged as promising targets for therapeutic intervention in recent years. In this review, general aspects of PTPs and the development of small‐molecule inhibitors of PTPs by both academic research groups and pharmaceutical companies are discussed. Different strategies have been successfully applied to identify potent and selective inhibitors. These studies constitute the basis for the future development of PTP inhibitors as drugs.
Underexpansion of sirolimus‐eluting stents: Incidence and relationship to delivery pressure
Authors: Cheneau Edouard , Satler Lowell F. , Escolar Esteban , Suddath William O. , Kent Kenneth M. , Weissman Neil J. , Waksman Ron , Pichard Augusto D.
Published: May 2005

We aimed to assess the incidence of underexpansion and the relationship between delivery pressure and expansion with sirolimus‐eluting stents. Adequate stent expansion contributes to early and late improved outcomes. In 51 patients (53 lesions) with native coronary artery narrowing, balloon‐expandable sirolimus‐eluting stents (Cypher) were serially expanded with gradual balloon inflations [14 atm, 20 atm, and in case of minimal stent cross‐sectional area (CSA)/reference lumen CSA < 50% at 20 atm, postdilatation with 0.5 mm larger balloon]. Intravascular ultrasound (IVUS) imaging was performed before intervention and after each gradual balloon inflation. Stent expansion (minimal stent CSA/reference lumen CSA) was measured. Stent expansion was 72% ± 16% after 14 atm balloon inflation, 90% ± 18% after 20 atm balloon inflation (P < 0.001 vs. 14 atm), and 90% ± 18% at the end of the procedure (including optional postdilatations with 0.5 mm larger balloon; P = NS vs. 20 atm). Stent expansion addressed by MUSIC criteria (all struts apposed, no tissue protrusion, and final lumen CSA > 80% of the reference or > 90% if minimal lumen CSA was < 9 mm2) was adequate in 15% of the cases after 14 atm balloon inflation, in 60% after 20 atm balloon inflation (P < 0.001 vs. 14 atm), and in 60% at the end of the procedure (P = NS vs. 20 atm). Sirolimus‐eluting stent underexpansion is common when deployed at conventional pressures. Increasing balloon delivery pressure or assessing stent expansion with IVUS seems warranted in order to ensure adequate sirolimus‐eluting stent deployment. © 2005 Wiley‐Liss, Inc.
Emergency stent graft deployment for acute aortic rupture following primary stenting for aortic coarctation
Authors: Tan Ju‐Le , Mullen Michael
Published: May 2005

We present a case of endovascular stenting for aortic recoarctation complicated by acute aortic rupture, which was successfully treated by emergency stent graft deployment. This case illustrates the potential serious complication that can occur during aortic stent dilatation and how the prompt deployment of a stent graft helped to change the clinical outcome of this life‐threatening situation. © 2005 Wiley‐Liss, Inc.
Fluoroscopic localization of the femoral head as a landmark for common femoral artery cannulation†
Authors: Garrett Paul D. , Eckart Robert E. , Bauch Terry D. , Thompson Christopher M. , Stajduhar Karl C.
Published: May 2005

We sought to determine the reliability of frequently used landmarks for femoral arterial access in patients undergoing cardiac catheterization. The common femoral artery (CFA) is the most frequently used arterial access in cardiac catheterization. Arterial sheath placement into the CFA has been shown to decrease vascular complications. Some authors recommend locating the inferior border of the femoral head using fluoroscopy due to the relationship of the femoral head and the bifurcation of the CFA. We performed a descriptive study in a prospective design of 158 patients undergoing catheterization from the femoral approach. A femoral angiogram was performed, and the CFA bifurcation location was recorded in relation to the inguinal ligament, middle and inferior border of the femoral head, and the inguinal skin crease. The CFA bifurcation was distal to the inguinal ligament, middle femoral head, and inferior femoral head in most patients with mean distances (cm ± SD) of 7.5 ± 1.7, 2.9 ± 1.5, and 0.8 ± 1.2, respectively. The inguinal skin crease was below the bifurcation in 78% of patients (−1.8 ± 1.6 cm). The CFA overlies the femoral head in 92% of cases. The femoral head has a consistent relationship to the CFA, and localization using fluoroscopy is a useful landmark. © 2005 Wiley‐Liss, Inc.
Technical details and programming guide for a general two‐way positive matrix factorization algorithm
Authors: Lu Jianhang , Wu Laosheng
Published: May 2005

In the past decade a factor analysis model named positive matrix factorization (PMF) has been increasingly used in analysis of environmental data. The PMF computing program is commercially available from its developer, but the technical details of the algorithm and program codes remain unpublished so far. For better documentation and facilitation of its application we present the technical details of a general two‐way PMF algorithm and provide a detailed guide for its programming. We explicitly explain the iterative procedure and construction of matrices and vectors used in the PMF algorithm and illustrate their implementations with ready‐to‐use Matlab codes. We also give our experiences and suggestions on various aspects of PMF programming, such as reducing memory need, improving computational efficiency and adjusting model parameters. The contents presented in this paper are helpful for one who would like to create his/her own PMF computing codes and thus be able to tailor the model for specific tasks or purposes. Copyright © 2005 John Wiley & Sons, Ltd.
A comparative study of linear regression methods in noisy environments
Authors: Reis Marco S. , Saraiva Pedro M.
Published: May 2005

With the development of measurement instrumentation methods and metrology, one is very often able to rigorously specify the uncertainty associated with each measured value (e.g. concentrations, spectra, process sensors). The use of this information, along with the corresponding raw measurements, should, in principle, lead to more sound ways of performing data analysis, since the quality of data can be explicitly taken into account. This should be true, in particular, when noise is heteroscedastic and of a large magnitude. In this paper we focus on alternative multivariate linear regression methods conceived to take into account data uncertainties. We critically investigate their prediction and parameter estimation capabilities and suggest some modifications of well‐established approaches. All alternatives are tested under simulation scenarios that cover different noise and data structures. The results thus obtained provide guidelines on which methods to use and when. Interestingly enough, some of the methods that explicitly incorporate uncertainty information in their formulations tend to present not as good performances in the examples studied, whereas others that do not do so present an overall good performance. Copyright © 2005 John Wiley & Sons, Ltd.
A new maximum entropy‐based method for deconvolution of spectra with heteroscedastic noise
Authors: Buttingsrud Bård , Alsberg Bjørn K.
Published: May 2005

Broadening of spectral lines combined with large and heteroscedastic noise contributions constitutes an important problem in analytical chemistry. Reduced interpretability and artefacts in further data analysis make deconvolution methods necessary. A new robust deconvolution method (RHEMEM) based on the principle of maximum entropy is proposed in order to effectively handle the presence of heteroscedastic noise. Other deconvolution methods such as Jansson's method, Fourier self‐deconvolution and LOMEP are also studied with respect to their ability to handle heteroscedastic noise. A systematic simulation study is used to compare the performance of the new method with the reference methods. They are evaluated according to reconstruction performance, robustness and the ability to work without manual input. Copyright © 2005 John Wiley & Sons, Ltd.
Controlling coverage of D‐optimal onion designs and selections
Authors: Olsson Ing‐Marie , Gottfries Johan , Wold Svante
Published: May 2005

Statistical molecular design (SMD) is a powerful approach for selection of compound sets in medicinal chemistry and quantitative structure–activity relationships (QSARs) as well as other areas. Two techniques often used in SMD are space‐filling and D‐optimal designs. Both on occasions lead to unwanted redundancy and replication. To remedy such shortcomings, a generalization of D‐optimal selection was recently developed. This new method divides the compound candidate set into a number of subsets (‘layers’ or ‘shells’), and a D‐optimal selection is made from each layer. This improves the possibility to select representative molecular structures throughout any property space independently of requested sample size. This is important in complex situations where any given model is unlikely to be valid over the whole investigated domain of experimental conditions. The number of selected molecules can be controlled by varying the number of subsets or by altering the complexity of the model equation in each layer and/or the dependency of previous layers. The new method, called D‐optimal onion design (DOOD), will allow the user to choose the model equation complexity independently of sample size while still avoiding unwarranted redundancy. The focus of the present work is algorithmic improvements of DOOD in comparison with classical D‐optimal design. As illustrations, extended DOODs have been generated for two applications by in‐house programming, including some modifications of the D‐optimal algorithm. The performances of the investigated approaches are expected to differ depending on the number of principal properties of the compounds in the design, sample sizes and the investigated model, i.e. the aim of the design. QSAR models have been generated from the selected compound sets, and root mean squared error of prediction (RMSEP) values have been used as measures of performance of the different designs. Copyright © 2005 John Wiley & Sons, Ltd.
Polystyrene‐Supported Organotin Dichloride as a Recyclable Catalyst in Lactone Ring‐Opening Polymerization: Assessment and Catalysis Monitoring by High‐Resolution Magic‐Angle‐Spinning NMR Spectroscopy
Authors: Deshayes Gaëlle , Poelmans Kevin , Verbruggen Ingrid , Camacho‐Camacho Carlos , Degée Philippe , Pinoie Vanja , Martins José C. , Piotto Martial , Biesemans Monique , Willem Rudolph , Dubois Philippe
Published: May 2005

Dialkyltin dichloride grafted to a cross‐linked polystyrene, with the formula [PH](1−t)[P(CH2)nSnBuCl2]t (P=[CH2CH(pC6H4)], t=the degree of functionalization, and n=6 or 11), is investigated as a recyclable catalyst in the ring‐opening polymerization (ROP) of ε‐caprolactone (CL). It is demonstrated that high‐resolution magic‐angle‐spinning (HR‐MAS) NMR spectroscopy is an invaluable tool to characterize completely the supported catalyst. The 2D 1H–13C HSQC HR‐MAS spectrum, in particular, allowed extensive assignment of the 1H and 13C resonances, as well as accurate measurement of the nJ(1H–117/119Sn) and nJ(13C–117/119Sn) coupling constants. 1H and 119Sn HR‐MAS NMR spectroscopy is presented as a monitoring tool for catalytic processes based on organotin compounds, particularly for the investigation of the extent to which polymerization residues are observable in situ in the material pores and for the assessment of the chemical integrity and recycling conditions of the grafted catalyst. From polymerization experiments with CL, initiated by n‐propanol and with [PH](1−t)[P(CH2)nSnBuCl2]t of various compositions as the supported catalyst, it appears that a partial 'burst' of the polystyrene support occurs when the length of the alkyl spacer is limited to n=6, as a result of polymer chains growing within the pores of the support. However, extension of the length of the aliphatic polymethylene spacer from 6 to 11 carbon atoms preserves the support integrity and allows the production of catalyst‐deprived poly(ε‐caprolactone) (PCL) oligomers. A preliminary attempt to recycle the heterogeneous catalyst has shown that very good reproducibility can be obtained, in terms of both catalyst activity and molecular‐weight parameters of the as‐recovered PCL polyester chains.
Sensing Nitrite through a Pseudoazurin–Nitrite Reductase Electron Transfer Relay
Authors: Astier Yann , Canters Gerard W. , Davis Jason J. , Hill H. Allen O. , Verbeet Martin P. , Wijma Hein J.
Published: May 2005

Nitrite is converted to nitric oxide by haem or copper‐containing enzymes in denitrifying bacteria during the process of denitrification. In designing an efficient biosensor, this enzymic turnover must be quantitatively assessed. The enzyme nitrite reductase from Alcaligenes faecalis contains a redox‐active blue copper centre and a nonblue enzyme‐active copper centre. It can be covalently tethered to modified gold‐electrode surfaces in configurations in which direct electron transfer is possible. A surface cysteine mutant of the enzyme can be similarly immobilised on bare electroactive gold substrates. Under such circumstances, however, electron transfer cannot be effectively coupled with substrate catalytic turnover. In using either the natural redox partner, pseudoazurin, or ruthenium hexammine as an “electron‐shuttle” or “conduit” between enzyme and a peptide‐modified electrode surface, the coupling of electron transfer to catalysis can be utilised in the development of an amperometric nitrite sensor.
Cross‐Linking of Polyolefins: A Study by Thermoporosimetry with Benzene Derivatives as Swelling Solvents
Authors: Billamboz Nicolas , Nedelec Jean‐Marie , Grivet Manuel , Baba Mohamed
Published: May 2005

The solvents o‐, m‐, p‐xylene, p‐dichlorobenzene, 1,2,4‐trichlorobenzene, and naphthalene were calibrated as condensates used in the thermoporosimetry technique. Exponential relationships were found connecting the pore radii Rp (in nm) and the freezing‐point depression of the swelling solvent ΔT (in °C) on the one hand and the apparent energy of crystallization Wa (in J cm−3) and ΔT on the other hand: ${{\rm R}{_{p}}={\rm t}\,exp[- 1/({\rm c}{\Delta}{\rm T})]}$; ${{\rm W}{_{a}}={\rm W}{_{0}}\,exp({\Delta}{\rm T}/{\rm f})}$. Pore‐ or mesh‐size distributions can be derived from differential scanning calorimetry results by using the following equation: ${d{\rm V}{_{p}}/d{\rm R}{_{p}}={\rm k}\{[{\rm cY}({\rm T}){\Delta}{\rm T}{^{2}}]/[{\rm W}{_{a}}{\rm R}{_{p}}]\}}$. All the numerical parameters were determined. Polyethylene and polypropylene samples, cross‐linked with high‐energy electrons or γ‐rays, were submitted to thermoporosimetry study. Relative mesh‐size distributions, which depend on the polymer/solvent pair, were calculated for these polyolefins with o‐, m‐, and p‐xylene as solvent and were found to be in the same sequence as those of their degrees of swelling and the irradiation doses received.
A Theoretical Investigation of Substituent Effects on the Absorption and Emission Properties of a Series of Terpyridylplatinum(II) Acetylide Complexes
Authors: Liu Xiao‐Juan , Feng Ji‐Kang , Meng Jian , Pan Qing‐Jiang , Ren Ai‐Min , Zhou Xin , Zhang Hong‐Xing
Published: May 2005

A comprehensive calculational investigation has been carried out on a series of complexes of the type [(terpyridyl‐R1)Pt(C≡C‐R2)], where terpyridyl‐R1 is a series of substituted 2,2':6',2''‐terpyridyl ligands and C≡C‐R2 is a series of substituted acetylide ligands. In one series of complexes (I), the energy of the electronic excited state is varied by changing the substituents on the terpyridyl ligand (R1). In a second series of complexes (II), this electronic structure variation is obtained by changing the para substituents (R2) of the acetylide ligand. The effect of varying the substituents on the lowest‐energy excited states of the complexes has been assessed by calculating their electronic structures and excitation energies. We anticipated that introduction of electron‐withdrawing substituents on the terpyridyl ligand will benefit the LLCT (or MLCT) and prohibit the nonradiative pathways via d‐d transitions in these complexes; introduction of electron‐donating substituents on the acetylide ligand can also prohibit the nonradiative pathways by increasing the energy gaps between the HOMO–LUMO and d‐d transitions. The results also reveal that the lowest‐energy excitations of all complexes of series I and IIa–b complexes are dominated by a π(C≡C) → π*(terp) (LLCT) transition mixed with some energetically dπ(Pt) → terpyridyl (MLCT) transition. However, for the complexes IIc–IId, in which phenyl rings are introduced on the acetylide ligand, the lowest‐lying absorptions of IIc and IId are predominately LLCT in character, with less MLCT mixture, due to a lower contribution of the Pt(d) orbital to the HOMO, while for IIe, with a stronger donor on the acetylide, the lowest‐lying absorption is completely LLCT in character. The absorption and emission calculations using the TDDFT method are based on the optimized geometries obtained at the B3LYP/LanL2DZ and CIS/LanL2DZ levels, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis and Reactions of Mixed N,P Ligands
Authors: Bowen Richard J. , Fernandes Manuel A. , Gitari Patricia W. , Layh Marcus , Moutloali Richard M.
Published: May 2005

The gold complexes [RN=C(R')CH(R)PPh2(AuCl)] (6a, R' = tBu; 6b, R' = Ad; R = SiMe3) were synthesised from the ketimines RN=C(R')CH(R)PPh2 (2a, R' = tBu; 2b, R' = Ad; R = SiMe3) and Me2SAuCl. The hydrolysis of the complexes to [H2NC(R')=CHPPh2(AuCl)] (8a, R' = tBu; 8b, R' = Ad) in protic solvents was studied and the reaction intermediate [H(R)NC(tBu)=CHPPh2(AuCl)] (7a) was isolated. The ketimines were further reacted with PhPCl2 to the cyclic phosphonium salts [Ph2PP(Ph)N(H)C(R')=CH]X (3a, R' = tBu, X = Cl; 3c, R' = Ad, X = Cl; 3d, R' = Ad, X = BPh4) and in the case of 3a oxidised with sulfur to give the ring‐opened β‐keto thiophosphane oxide Ph2P(S)CH2C(O)tBu (9). All compounds were fully characterised by NMR spectroscopy and in the case of 6b, 8a and 9 by X‐ray crystallography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
The Role of C–H···O Interactions in the Solid and Liquid‐Phase Structures of Methyltrioxo Rhenium
Authors: Vaz Pedro D. , Ribeiro‐Claro Paulo J. A.
Published: May 2005

The importance of C–H···O hydrogen bonds involving the less common Re=O acceptor group in the small organometallic methyltrioxorhenium (MTO) is studied by combined vibrational spectroscopy and ab initio calculations. The observed vibrational spectrum is well described by the calculated spectrum of a C–H···O bonded dimer, which accounts for the symmetry decrease and the intermolecular interactions in the solid. Spectral evidence indicates both C–H···O and O–H···O hydrogen bonds are formed in the MTO/methanol solutions. The Re=O stretching mode is sensitive to hydrogen bonding, but the major effects of intermolecular association are observed in the βC–H and νC–H modes of MTO. Ab initio calculations for the MTO/methanol system predict the coexistence of both the Lewis adduct and the hydrogen‐bonded complex, with an energy difference of ca. 1.2 kJ·mol–1. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
The Structural Chemistry of N‐Monolithium Borazines
Authors: Nöth Heinrich , Rojas‐Lima Susana , Troll Alexander
Published: May 2005

Trimethylborazine (Me3B3N3H3, 1) reacts with RLi (R = nBu, tBu) in hexane solution by alkyl group exchange to give a mixture of borazines Me3–nRnB3N3H3. In contrast, deprotonation of 1 to Me3B3N3H2Li (2) occurs upon treatment with MeLi in diethyl ether solution or RLi (R = nBu, tBu) complexed with tetramethylethylenediamine (TMEDA), pentamethyldiethylentriamine (PMDTA), or trimethylhexahydrotriazine (TMTA) in hexane solution, to give solvates of 2. [(Me3B3N3H2)Li(OEt2)] (2a), [(Me3B3N3H2)Li(tmta)] (2c), and [(Me3B3N3H2Li)4(tmeda)3] (2b) contain dimeric units of 2. In the case of 2b two of these dimers are bridged by one tmeda molecule, while the other two are coordinated to a lithium atom of one of its dimeric units, respectively. This molecule therefore contains tri‐ and tetracoordinated Li atoms. In contrast, [(Me3B3N3H2)Li(pmdta)] (2c) is monomeric. The N‐lithiation leads to a distortion of the planar B3N3 ring system: the B–N bonds at the metallated N atoms are short, the next opposite B–N pair is the longest, followed by a shorter B–N bond involving the B atom in the para position. However, all B–N bonds are longer than in the parent compound 1. Reaction of tBu3B3N3H3 (3) with tBuLi in the presence of triisopropylhexahydrotriazine (TIPTA) in hexane leads to the salt [(tipta)2Li][tBu4B3N3H3] (4), while deprotonation occurs with tBuLi(tmta) to give monomeric [(tBu3B3N3H2)Li(tmta)] (5) after refluxing the reaction mixture. Similarly, (Me2N)3B3N3H3 (6) can be deprotonated with RLi in the presence of TMTA to give monomeric [{(Me2N)3B3N3H2}Li(tmta)] (7b). The N‐lithiation has almost no influence on the shielding of the boron nucleus of the borazine nuecleus. Attempts to obtain di‐ and trilithiated 1 as pure compounds failed: alkyl group exchange and borate formation as well as destruction of the borazine ring were detected by NMR spectroscopy. However, treatment of these reaction mixtures with MeBr gave Me3B3N3NH3–nMen (n = 0–3). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Supramolecular Copper Phenanthroline Racks: Structures, Mechanistic Insight and Dynamic Nature
Authors: Kalsani Venkateshwarlu , Bodenstedt Heinrich , Fenske Dieter , Schmittel Michael
Published: May 2005

Herein, we describe the preparation of several dynamic multicomponent supramolecular racks based on copper phenanthroline complexes using the HETPHEN concept (heteroleptic bisphenanthroline complexes). This approach employs bulky aryl substituents at the bisimine coordination sites to control the coordination equilibrium. The racks were characterised by spectroscopic methods, both in solution (1H NMR, ESI‐MS, UV/Vis, vapour pressure osmometry) and in the solid state (X‐ray). Ligand exchange studies established the reversible nature of the aggregates, the details of which are vital for the development of higher level multicomponent structures. In this regard, the present rack assemblies contrast to the large multitude of known rack motifs that are almost exclusively built using kinetically inert coordination building blocks. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis, Characterization and Photophysical Properties of Novel Dinuclear Silver(I) and Mononuclear Palladium(II) Complexes with 1,2‐Bis[(anthracen‐9‐ylmethyl)amino]ethane
Authors: Zhang Guo‐qi , Yang Guo‐qiang , Yang Lan‐ying , Chen Qing‐qi , Ma Jin‐Shi
Published: May 2005

Silver(I) (3) and palladium(II) (4) complexes of 1,2‐bis[(anthracen‐9‐ylmethyl)amino]ethane have been synthesized and structurally characterized. X‐ray crystal structure analysis reveals that compound 3 exists as a dinuclear tris(ligand) complex with formula [Ag2(2)3]·2NO3, in which each silver center is three‐coordinate to form a slightly distorted planar‐trigonal geometry with three nitrogen donors originating from two distinct ligands. Compound 4, on the other hand, is a mononuclear bis(ligand) complex with formula [Pd(2)2]·2OAc, in which the palladium center is four‐coordinate with four nitrogen donors originating from two distinct ligands to form a square‐planar geometry. In crystals of both 3 and 4 strong intermolecular edge‐to‐face C–H···π packing interactions are observed, which contribute to stabilize the crystalline solid. Studies of the photophysical properties of these compounds (3, 4, and ligand 2) show apparent fluorescence quenching effect by introduction of metal ions and likely “excimer” emission of anthracene in the crystalline solid. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Di‐2‐pyridyl Ketone Oxime in Zinc Chemistry: Inverse 12‐Metallacrown‐4 Complexes and Cationic Pentanuclear Clusters
Authors: Alexiou Maria , Katsoulakou Eugenia , Dendrinou‐Samara Catherine , Raptopoulou Catherine P. , Psycharis Vassilis , Manessi‐Zoupa Evy , Perlepes Spyros P. , Kessissoglou Dimitris P.
Published: May 2005

The use of di‐2‐pyridyl ketone oxime (Hpko)/X– “blends” (X– = PhCO2–, N3–, NCO–, acac–, NCS–) in zinc chemistry yields neutral tetranuclear and cationic pentanuclear clusters. Various synthetic procedures have led to the synthesis of compounds [Zn4(OH)2(O2CPh)2(pko)4]·3MeCN (1·3MeCN), [Zn4(OH)2(N3)2(pko)4]·4DMF (2·4DMF), [Zn4(OH)2(NCO)2(pko)4]·3DMF·H2O (3·3DMF·H2O), [Zn4(OH)2(acac)2(pko)4]·4CH2Cl2 (4·4CH2Cl2), [Zn5Cl2(pko)6][ZnCl(NCS)3]·2.5H2O·1.5MeOH (5·2.5H2O·1.5MeOH) and [Zn5(NCS)2(pko)6(MeOH)][Zn(NCS)4]·2.5H2O·MeOH (6·2.5H2O·MeOH). The structures of the six complexes have been determined by single‐crystal X‐ray crystallography. The tetranuclear molecules of 1–4 lie on a crystallographic inversion centre and have an inverse 12‐metallacrown‐4 topology. Two triply bridging hydroxides are accommodated in the centre of the metallacrown ring. The pko– ligands form a propeller configuration that imposes absolute stereoisomerism with Λ and Δ chirality. Two metal ions are in distorted O2N4 octahedral environments, whereas the rest are in severely distorted tetrahedral or trigonal bipyramidal environments. The five Zn ions of the cations of 5 and 6 are held together by six pko– ligands which adopt three different coordination modes; the chloro (5) and isothiocyanato (6) ligands are terminal. The five Zn ions define two nearly equilateral triangles sharing a common apex, and the novel Zn5 topology can be described as two “collapsed” 9‐metallacrown‐3 structures sharing a common Zn apex. Besides the pentanuclear cations, the structures of 5 and 6 contain slightly distorted tetrahedral [ZnCl(NCS)3]2– and [Zn(NCS)4]2– ions, respectively, with the isothiocyanato ligands binding the metal ion in a virtually linear fashion. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Structures, Electronic States and Electroluminescent Properties of a Series of CuI Complexes
Authors: Yang Li , Feng Ji‐Kang , Ren Ai‐Min , Zhang Ming , Ma Yu‐Guang , Liu Xiao‐Dong
Published: May 2005

A series of new mixed‐ligand copper(I) complexes [Cu(NN)POP]BF4, where NN = 1,10‐phenanthroline (phen; 1a), 2,9‐dimethyl‐phen (DMphen; 1b), 4,7‐diphenyl‐phen (DPpehn; 1c) and 2,2'‐bipyridine (bpy; 2a), have been synthesized. Density functional theory (DFT) was applied to study the ground‐ and excited‐state properties of these copper(I) complexes. The electronic structure variation is obtained by changing the substituted positions on the phenanthroline ligand. A time‐dependent‐DFT approach (TDDFT) was used to interpret the absorption and emission spectra in this system based on the optimized geometries at the B3LYP/LANL2DZ and CIS/LANL2DZ levels of theory, respectively. The results show that the lowest‐energy excitations of all complexes are dominated by dπ(Cu)→π*(phen) or bpy (MLCT) excitations. In particular, the lowest triplet state (T1) corresponds to an excitation from the HOMO to the LUMO in all considered complexes, and emissions occur from T1, assigned to 3MLCT. Steric effects exerted by the pendent groups at the 2‐ and 9‐positions of the phenanthroline ligands increase the HOMO–LUMO gaps and thus lead to a blue‐shift of both absorption and emission spectra and effectively prevent structural relaxation in the MLCT state, which may narrow the energy gap between the excited and ground states and therefore increase nonradiative decay. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
N‐Bonded Monosilanols: Synthesis and Characterization of ArN(SiMe3)SiMe2Cl and ArN(SiMe3)SiMe2OH (Ar = C6H5, 2,6‐Me2C6H3,2,6‐iPr2C6H3)
Authors: Chandrasekhar Vadapalli , Boomishankar Ramamoorthy , Azhakar Ramachandran , Gopal Kandasamy , Steiner Alexander , Zacchini Stefano
Published: May 2005

By the use of aniline and the sterically hindered aromatic primary amines, 2,6‐Me2C6H3NH2 and 2,6‐iPr2C6H3NH2, N‐bonded monochlorosilanes, ArN(SiMe3)SiMe2Cl [Ar = C6H5 (1a), Ar = 2,6‐Me2C6H3 (1b) and Ar = 2,6‐iPr2C6H3 (1c)] have been prepared by a sequential deprotonation at the nitrogen followed by reaction with silyl chlorides. Hydrolysis of the N‐bonded monochlorosilanes afforded the N‐bonded monosilanols ArN(SiMe3)SiMe2OH [Ar = C6H5 (2a), Ar = 2,6‐Me2C6H3 (2b) and Ar = 2,6‐iPr2C6H3 (2c)]. The X‐ray crystal structure of 1c reveals a positional disorder of the Cl and CH3 substituents on silicon. The X‐ray crystal structure of 2c shows that it is involved in an intermolecular O–H···O hydrogen bonding in the solid state to afford a dimeric structure containing the O2H2 ring. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Low‐Valent Titanium–Pentafulvene Complexes – Formation of Dinuclear Titanium–Nitrogen Complexes
Authors: Scherer Axel , Kollak Kay , Lützen Arne , Friedemann Marion , Haase Detlev , Saak Wolfgang , Beckhaus Rüdiger
Published: May 2005

In a late stage of production Equation (2) on p. 1006 of the print version[1] was inadvertently replaced by a copy of Equation (3); the electronic version is free of this error. The correct Equation (2) is shown below.
Hyrtiosins A–E, Five New Scalarane Sesterterpenes from the South China Sea Sponge Hyrtios erecta
Authors: Yu Zhi‐Guo , Bi Kai‐Shun , Guo Yue‐Wei
Published: May 2005

Five new scalarane sesterterpenes, hyrtiosins A–E (1–5), together with three previously reported sesterterpenes, 25‐dehydroxy‐12‐epi‐scalarin (6), 12‐epi‐scalarin (7) and heteronemin (9), were isolated from the South China Sea sponge Hyrtios erecta. Their structures were determined on the basis of extensive NMR studies and high‐resolution MS measurements.
Asymmetric 1,3‐Dipolar Cycloadditions of 2‐Diazocyclohexane‐1,3‐diones and Alkyl Diazopyruvates
Authors: Müller Paul , Chappellet Sabrina
Published: May 2005

The 1,3‐dipolar cycloaddition reactions of 2‐diazocyclohexane‐1,3‐dione (7a; Table 1) and of alkyl diazopyruvates (11a–e; Table 3) to 2,3‐dihydrofuran and other enol ethers have been investigated in the presence of chiral transition metal catalysts. With RhII catalysts, the cycloadditions were not enantioselective, but those catalyzed by [RuIICl2(1a)] and [RuIICl2(1b)] proceeded with enantioselectivities of up to 58% and 74% ee, respectively, when diazopyruvates 11 were used as substrates. The phenyliodonium ylide 7c yielded the adduct 8a in lower yield and poorer selectivity than the corresponding diazo precursor 7a (Table 2) upon decomposition with [Ru(pybox)] catalysts. This suggests that ylide decomposition by RuII catalysts, contrary to that of the corresponding diazo precursors, does not lead to Ru‐carbene complexes as reactive intermediates. Our method represents the first reproducible, enantioselective 1,3‐cycloaddition of these types of substrates.
Sarcophytonolides A–D, Four New Cembranolides from the Hainan Soft Coral Sarcophyton sp.
Authors: Jia Rui , Guo Yue‐Wei , Mollo Ernesto , Cimino Guido
Published: May 2005

Four new cembranolide diterpenes, sarcophytonolides A–D (1–4), were isolated from a Hainan soft coral Sarcophyton sp. Their structures were elucidated on the basis of detailed spectroscopic analysis and by comparison with related model compounds.
Use of Dibutyl[14C]formamide as a Formylating Reagent in the Vilsmeier–Haack Reaction and Synthesis of a 14C‐Labeled Novel Phosphodiesterase‐4 (PDE‐4) Inhibitor
Authors: Ho Jonathan Z. , Elmore Charles S. , Wallace Michael A. , Yao Dan , Braun Matthew P. , Dean Dennis C. , Melillo David G. , Chen Cheng‐yi
Published: May 2005

A simple, high‐yielding synthesis of dibutyl[14C]formamide ([14C]DBF; 1) from 14CO2 was developed (Scheme 1): reaction of LiBEt3H and 14CO2 followed by aqueous workup gave H14CO2H in high yield. Conversion of the [14C]formic acid to 1 was effected by a standard carbodiimide coupling procedure. The utility of 1 as an alternative to dimethyl[14C]formamide ([14C]DMF) in alkylation reactions and in the [14C]Vilsmeier–Haack reaction was demonstrated for several substrates (Table 2). A 14C‐labeled phosphodiesterase‐4 (PDE‐4) inhibitor, [14C]‐2, was synthesized by application of this technology (Scheme 2).
New Iridoid Triesters from Valeriana jatamansi
Authors: Yu Lili , Huang Rong , Han Changri , Lv Yuping , Zhao Yong , Chen Yegao
Published: May 2005

Two new iridoid triesters, valeriotriates A (1) and B (2), were isolated from the roots of Valeriana jatamansi Jones. Their structures were elucidated by HR‐ESI‐MS and 1D‐ and 2D‐NMR spectroscopy.
Reductive Elimination of Phenylsulfonyl Groups in the 3‐Position of Benzo[a]heptalene‐2,4‐diols
Authors: eldin Abdel Fattah Mohy , El Rayes Samir , Soliman El Sayed Ahmed , Linden Anthony , Abou‐Hadeed Khaled , Hansen Hans‐Jürgen
Published: May 2005

3‐(Phenylsulfonyl)benzo[a]heptalene‐2,4‐diols 1 can be desulfonylated with an excess of LiAlH4/MeLi⋅LiBr in boiling THF in good yields (Scheme 6). When the reaction is run with LiAlH4/MeLi, mainly the 3,3′‐disulfides 6 of the corresponding 2,4‐dihydroxybenzo[a]heptalene‐3‐thiols are formed after workup (Scheme 7). However, the best yields of desulfonylated products are obtained when the 2,4‐dimethoxy‐substituted benzo[a]heptalenes 2 are reduced with an excess of LiAlH4/TiCl4 at −78→20° in THF (Scheme 10). Attempts to substitute the PhSO2 group of 2 with freshly prepared MeONa in boiling THF led to a highly selective ether cleavage of the 4‐MeO group, rather than to desulfonylation (Scheme 13).