bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and Standardisation of Scale to Measure Attitude of the Farmers towards Natural Farming: A Sustainable Environmental Approach
Authors: Deepika Mupparapu , Gopal P.V.Sathya , Reddy K. Gurava , Sailaja V. , Reddy G. Krishna , Kumari P. Lavanya
Published: May 2024

Attitude is defined as the degree of favourable or unfavourable feeling of the farmers towards natural farming. Natural farming, a sustainable agricultural practice that eschews synthetic inputs, has garnered significant interest globally for its potential to enhance soil health, biodiversity and crop resilience. Understanding farmer’s attitude towards natural farming is crucial for its widespread adoption. It is the accepted fact that attitude of an individual plays an important role in determining ones behaviour. Keeping this in view a standardized scale has been developed to assess the attitude of the farmers towards natural farming. The Likert’s summated rating method was used to construct the scale. The process started with collection of items followed by relevancy testing and item analysis and checking the reliability and validity for precision and consistency. A total of twenty four statements were finally retained for measuring attitude of the farmers towards natural farming, out of which fourteen statements were positive and ten statements were negative. The reliability was checked using split-half method and validity was examined through content validity. The scale developed was found highly reliable and valid.
Efficacy of Certain Chemicals and Botanicals against Shoot and Fruit Borer, Leucinodes orbonalis (Guenee) on Brinjal (Solanum melongena L.)
Authors: Upadhyay Shitanshu , Tayde Anoorag R , Tripathi Akhilesh
Published: May 2024

The field trial was conducted at Central research farm , SHUATS, Prayagraj, U.P during Kharif season 2023 in randomized block design (RBD) with three replications consisting of eight treatment viz, Neem oil 2%,  Chlorantraniliprole 18.5% SC , Spinosad 45%SC, Flubendiamide 480 SC, Indoxacarb 14.5% SC, Pangomia + Flubendiamide,  Neem oil + Flubendiamide, and untreated  Control, The result revealed that all insecticidal treatments were significantly superior to reduce the incidence of shoot and fruit damage of brinjal compared to untreated control. The plot treated with Chlorantraniliprole 18.5% SC recorded the lowest % of shoot and fruit damage 4.03% and 3.20 % in first and second sprays, respectively followed by spinosad 45% SC (4.43% and 4.15% respectively). The yield ranged from 85 to 225.50 q/ha in all treatments. The highest yield was recorded in Chlorantraniliprole 18.5 % SC (225q/ha) followed by spinosad 45% SC (190q/ha), Flubendiamide 480 SC (17.50q/ha), Indoxacarb 14.5 SC (160.35q/ha), Pangomia + Flubendiamide (140.33q/ha), Neem oil + Flubendiamide (132.40q/ha) and Neem oil 2% (120.50q/ha) as compared to control (85.00q/ha). When cost benefit worked out the best and most economical treatment was Chlorantraniliprole 18.5% SC (1:10.3) followed by Spinosad 45% SC (1:8.5), Flubendiamide 480 SC (1:7.5), Indoxacarb14.5 SC (1:7.4), Pangomia + Flubendiamide (1:6.0), Neem oil + Flubendiamide (1:5.5) and Neem oil 2% (1:5.4) as compared to control (1:4.2).
Assessment of Physico-chemical Properties of Soil from Various Regions of Different Taluk of Pathanamthitta District in the State of Kerala, India
Authors: Krishnan Nithya , Swaroop Narendra , Thomas Tarence , Mohanta Satya Ranjan , Thomas Ashima
Published: May 2024

The assessment of Physico-Chemical Properties of Soil from Various Regions of Different Taluk of Pathanamthitta District of Kerala in 2023-24 was a valuable endeavour. A total of 27 samples were collected at profile depths of 0-15, 15-30, and 30-45. It is interesting to note the variations in soil colour between dry and wet conditions, ranging from light brown to dark reddish brown.The soil textural class was identified as Sandy clay Loam, and the sand, silt and clay percentage varied from 45.18% to 50.64%, 17.21% to 20.70%, 30.91% to 34.61%. Bulk Density was varied from 1.08 Mg m-3 to 1.28 Mg m-3. The Particle Density varied from 2.02 Mg m-3 to 2.55 Mg m-3. The Pore Space (%) ranged from 40.18% to 50.62%. The Water Retaining Capacity (%) ranged from 39.19 to 48.98%. The pH value ranged from 4.9 to 6.9. The Electrical Conductivity ranged from 0.03 to 0.30 dS m-1. The value of total Organic Carbon (%) varied from 0.16 to 1.68 %. The available Nitrogen content of soil ranged from 119.45 to 286.07 kg ha-1. The available Phosphorus content of soil ranged from 13.23 to 64.20 kg ha-1. Available Potassium content of soil ranged from 100.80 to 382.40 kg ha-1. Exchangeable Calcium content of soil ranged from 1.7(meq 100g-1) to 9.1(meq 100g-1). Exchangeable Magnesium content of soil ranged from 0.23 (meq 100g-1) to 0.74(meq 100g-1). The Sulphur content of soil ranged from 0.03 to 0.44 kg ha-1. The findings revealed minor increases in bulk and particle density with depth, yet the overall physical condition of the soil seems favourable for plant growth. It is evident that the soils are slightly acidic but meet the acceptable EC limit. The high levels of Organic Carbon are promising, while Nitrogen is lower and Phosphorus and Potassium levels are moderate to high. However, secondary nutrients like Calcium, Magnesium, and Sulphur are relatively low. Nutrient levels appear to be influenced by soil depth, with leaching due to higher precipitation levels in the area contributing to nutrient deficiencies. The results suggest that improvements can be made by implementing strategies such as cover crops, green manure, legume cultivation, mulching, and specific cropping systems to address leaching concerns.
Foliar Application of Seaweed Extract and Micronutrients on Plant Growth and Yield of Strawberry (Fragaria X ananassa Duch) CV. Winter Dawn
Authors: Bagh Aishwaryditya Singh , Mishra Saket
Published: May 2024

The review summarizes the findings from recent studies, assessing the impact of foliar application of seaweed extracts and micronutrients on strawberry plants. Improvements in growth parameters, nutrient uptake, TSS, and yield attributes were observed. The study also determines whether adding seaweed extracts and micronutrients to strawberry growth methods can improve plant performance in general and fruit yield in particular. Minerals, amino acids, and plant growth regulators are among the bioactive substances found in seaweed extracts that have been shown to have a positive impact on a number of plant physiological functions. Furthermore, vitamin shortages might result in decreased growth and yield because they are essential to the plant's metabolic processes. The combination of micronutrients and seaweed extract has synergistic effects that offer a promising way to boost the general health and yield of strawberry crops.
The Role of Greenhouse Technology in Streamlining Crop Production
Authors: Singh Kunwar Akhand Pratap , Goutam Pawan Kumar , Xaxa Sindhu , Nasima . , Pandey Shivam Kumar , Panotra Narinder , G M Rajesh
Published: May 2024

Greenhouse technology has revolutionized modern agriculture by enabling year-round crop production, optimizing resource utilization, and enhancing crop yields and quality. This comprehensive review explores the multifaceted role of greenhouse technology in streamlining crop production processes. It delves into the principles of greenhouse design, covering essential components such as structural materials, covering materials, and environmental control systems. The article discusses the advantages of greenhouse cultivation, including extended growing seasons, protection from adverse weather conditions, and reduced pest and disease pressure. It examines the use of advanced technologies like hydroponics, aeroponics, and aquaponics in greenhouse systems, highlighting their potential for maximizing resource efficiency and minimizing environmental impact. The review also addresses the integration of precision agriculture techniques, such as sensors, automation, and data analytics, for optimizing greenhouse operations. Furthermore, it explores the economic aspects of greenhouse crop production, including initial investment costs, operational expenses, and market opportunities. The article emphasizes the importance of sustainable practices in greenhouse agriculture, focusing on energy conservation, water management, and waste reduction strategies. It also discusses the challenges associated with greenhouse technology adoption, such as high initial costs, technical complexity, and the need for skilled labor. Finally, the review concludes by outlining future research directions and the potential for greenhouse technology to contribute to global food security and sustainable agricultural practices.
Corrosion Protection of Mild Steel in Simulated Offshore Environment Using Ocimum gratissimum Leaf Extract
Authors: Ibeaja Adamma Chinyere E., , Onuabuchi Ifeanyi Augustine, , Ugorji Chinonso Chiagoziem,
Published: May 2024

The inhibitive action of Ocimum gratissimum leaf extracts on mild steel corrosion in 1M HCl and 0.5 NaCl solutions was studied using the Gravimetric technique. Four weighed well-polished coupons suspended into sample bottles labeled 200mg/l, 400mg/l, 800mg/l, 1200mg/l and the blank respectively was used. The results shown in Tables 1 to 5 is the weight loss data of mild steel in 0.1 M HCl and the effects of Ocimum gratissimum introduction and how the mild steel corroded progressively thereby increasing the weight loss value over immersion time as seen in Fig. 1. Fig. 2 shows the effects of Ocimum gratissimum extract concentration on the corrosion rate of mild steel in HCl, it is evident that increase in the concentration of the extract led to the decrease in the value of weight loss leading to appreciable inhibition efficiency. The plot in Fig. 3 showed that the values of the inhibition efficiency increased with the concentration of Ocimum gratissimum extract in the acidic environment except the value for 9 days which decreased with concentration. These results led to decrease in the values of inhibition efficiency over time as shown in Fig. 4. Tables 6 to 10 shows the weight loss data for the corrosion of mild steel in 0.5 M NaCl and the effects of Ocimum gratissimum introduction. The result showed that mild steel corroded, leading to fluctuations in the inhibition efficiency. Figs. 5-8 showed the variations of efficiency with time with different concentrations of Ocimum gratissimum in 0.5 M NaCl. Addition of Ocimum gratissimum extract synergistically increased the efficiency of the inhibitor and helped reduce the corrosion rate. A mechanism of adsorption is proposed to explain inhibition behaviour.
A Novel Efficient and Biodegradable Natural Catalyst and Bio Based Solvents for the Green One Pot Three Component Synthesis of Tetrahydrobenzo[B]pyran and 3,4-Dihydropyrano[C]chromenes
Authors: Kakeshpour A. , Moradi A. , Maghsoodlou M. T. , Moradi F.
Published: May 2024

This study presents a novel and efficient method for synthesizing Tetrahydrobenzo[b]pyran and 3,4-Dihydropyrano[c]chromene derivatives using honey as a highly efficient homogeneous catalyst. Through a one-pot three-component condensation of aromatic aldehydes with malononitrile and dimedone or 4-hydroxycoumarin, excellent yields were achieved under environmentally friendly conditions. The utilization of honey, a non-toxic and biodegradable catalyst, underscores the method's significance in green chemistry. The abstract highlights the method's advantages, including high yields, short reaction times, simple work-up, and its potential for applications in the green pharmaceutical and chemical industries. Additionally, the intricate role of honey as a catalyst in chemical reactions is explored, shedding light on its mechanism and potential applications in organic synthesis and other chemical processes. This research introduces a promising and environmentally friendly approach for the green synthesis of biologically active heterocyclic compounds using a natural, biodegradable catalyst, contributing significantly to the advancement of green chemistry practices.
A Smirk of Satisfaction: Study on Panama Cafe Consumers
Authors: Haeruddin Muhammad Ilham Wardhana
Published: May 2024

Aims: The success of a business cannot be separated from customer satisfaction. Consumer satisfaction or customer satisfaction is also an important factor in building a business. Satisfied consumers will certainly increase sales from the company. Consumer satisfaction is the level of consumer feelings after comparing what he received with what he expected. The purpose of this study is to find solutions to problems among product quality, service quality, and price on customer satisfaction.
Study Design:  Quantitative descriptive.
Place and Duration of Study: The sample used in this study were consumers who made purchases at Panama Cafe in Makassar City during the period January to March 2024.
Methodology: This research is a descriptive quantitative study conducted from January to March 2024. Sampling using purposive sampling method. The total sample in this research are 50 customers (22 male, 22 female, age range 15-35 years) who made more than two purchases. Data collection uses a questionnaire, which will be tested for validity and reliability, with the help of SPSS to processing data.
Results: The Product Quality variable has a T count of 0.471 and a significant value obtained of 0.640> 0.05. Thus it can be said that the product quality variable does not have a positive and significant effect on customer satisfaction. The Service Quality variable has a T count of 2.030 and a significant value obtained of 0.048 <0.05. Therefore, it can be concluded that the service quality variable has a significant and significant influence on customer satisfaction. The Price variable has a T count of 4.781 and a significant value obtained of 0.000 <0.05. Hence it can be concluded that the service quality variable has an influence and is significant to customer satisfaction.
Conclusion: Product quality has no influence on customer satisfaction, while service quality and price have an influence on customer satisfaction at Panama Cafe in Makassar city.
Quantifying Interfacial Electric Fields and Local Crystallinity in Polymer–Fullerene Bulk‐Heterojunction Solar Cells
Authors: Gearba Raluca I. , Mills Travis , Morris Josh , Pindak Ron , Black Charles T. , Zhu Xiaoyang
Published: May 2011

The challenges of experimentally probing the physical and electronic structures of the highly intermixed organic semiconductor blends that comprise active layers in high‐performance organic photovoltaic (OPV) cells ultimately limit the fundamental understanding of the device performance. We use Fourier‐transform IR (FTIR)‐absorption spectroscopy to quantitatively determine the interfacial electric field in blended poly(3‐hexylthiophene) (P3HT):phenyl‐ C61‐butyric acid methyl ester (PCBM) thin films. The interfacial electric field is ≈0.2 V nm−1 in the as‐spun film and blends annealing at temperatures as high as 150 °C, which is the optimal annealing temperature in terms of OPV performance. The field decreases to a negligible value upon further annealing to 170 °C, at which temperature PCBM changes from amorphous to crystalline and the open‐circuit voltage of the solar cell decreases from 0.62 to 0.4 V. In addition, our measurements also allow determination of the absolute degree of crystallinity within the acceptor material. The roles of interfacial field and local crystallinity in OPV device performance are discussed.
Preparation of 5‐Membered Rings via Radical Addition‐ Translocation‐Cyclization (RATC) Processes Mediated by Diethyl Thiophosphites
Authors: Lamarque Christophe , Beaufils Florent , Dénès Fabrice , Schenk Kurt , Renaud Philippe
Published: May 2011

A practical method for the formation of thiophosphonates bearing functionalized monocyclic, fused bicyclic and spirocyclic residues is presented. The procedure requires the easily available terminal alkynes as starting materials as well as commercially and readily available reagents such as diethyl thiophosphite. The experimental procedure consists of a one‐pot process without any slow addition of one of the reagents.
A Simple Procedure for Selective Hydroxylation of L‐Proline and L‐Pipecolic Acid with Recombinantly Expressed Proline Hydroxylases
Authors: Klein Christian , Hüttel Wolfgang
Published: May 2011

Due to their diverse regio‐ and stereoselectivities, proline hydroxylases provide a straightforward access to hydroxprolines and other hydroxylated cylic amino acids, valuable chiral building blocks for chemical synthesis, which are often not available at reasonable expense by classical chemical synthesis. As yet, the application of proline hydroxylases is limited to a sophisticated industrial process for the production of two hydroxyproline isomers. This is mainly due to difficulties in their heterologues expression, their limited in vitro stability and complex product purification procedures. Here we describe a facile method for the production of cis‐3‐, cis‐4‐ and trans‐4‐proline hydroxylase, and their application for the regio‐ and stereoselective hydroxylation of L‐proline and its six‐membered ring homologue l‐pipecolic acid. Since in vitro catalysis with these enzymes is not very efficient and conversions are restricted to the milligram scale, an in vivo procedure was established, which allowed a quantitative conversion of 6 mM l‐proline in shake flask cultures. After facile product purification via ion exchange chromatography, hydroxyprolines were isolated in yields of 35–61% (175–305 mg per flask). L‐Pipecolic acid was converted with the isolated enzymes to prove the selectivities of the reactions. In transformations with optimized iron(II) concentration, conversions of 17–68% to hydroxylated products were achieved. The regio‐ and stereochemistry of the products was determined by NMR techniques. To demonstrate the applicability of the preparative in vivo approach for non‐physiological substrates, L‐pipecolic acid was converted with an E. coli strain producing trans‐4‐proline hydroxylase to trans‐5‐hydroxy‐L‐pipecolic acid in 61% yield. Thus, a synthetically valuable group of biocatalysts was made readily accessible for application in the laboratory without a need for special equipment or considerable development effort.
Direct Synthesis of 6‐Azabicyclo[3.2.1]oct‐6‐en‐2‐ones and Pyrrolizidines from Divinyl Ketones and Observation of Remarkable Substituent Effects
Authors: Xu Xianxiu , Li Yifei , Zhang Yu , Zhang Lingjuan , Pan Ling , Liu Qun
Published: May 2011

Substituents create access to molecular diversity. Under basic conditions, 6‐azabicyclo[3.2.1]oct‐6‐en‐2‐ones 3 and pyrrolizidines 4 are efficiently synthesized, respectively, in a single step from ethyl isocyanoacetate 2 and divinyl ketones 1 bearing an aryl or alkyl group at the 2‐position. For comparison, only the corresponding pyrrolizidines 4′ can be obtained from divinyl ketones 1′ bearing a methoxycarbonyl group at the 2‐position.
Highly Active and Diastereoselective N,O‐ and N,N‐Yttrium Complexes for Intramolecular Hydroamination
Authors: Lauterwasser Frank , Hayes Paul G. , Piers Warren E. , Schafer Laurel L. , Bräse Stefan
Published: May 2011

The intramolecular hydroamination of aminoalkynes and unactivated aminoalkenes catalyzed by yttrium N,O‐ and N,N‐complexes has been investigated. The N,N‐yttrium complexes are highly active, catalyzing the conversion of a wide range of terminal aminoalkenes at room temperature, and internal aminoalkenes at elevated temperature, to yield pyrrolidine and piperidine products in high yields. A high diastereoselectivity of up to 23:1 is observed at 0 °C with 1‐methyl‐4‐pentenylamine as substrate.
Gold‐Catalyzed Direct Intermolecular Coupling of Ketones, Secondary Amines, and Alkynes: A Facile and Versatile Access to Propargylic Amines Containing a Quaternary Carbon Center
Authors: Cheng Ming , Zhang Qiang , Hu Xiao‐Yu , Li Bo‐Gang , Ji Jian‐Xin , Chan Albert S. C.
Published: May 2011

The first gold‐catalyzed direct intermolecular coupling of ketones, secondary amines, and alkynes was achieved under mild and solvent‐free conditions. The present methodology provides a promising and versatile tool for the construction of propargylic amines with a newly‐formed quaternary carbon center.
Synthesis, Rhodium Complexes and Catalytic Applications of a New Water‐Soluble Triphenylphosphane‐Modified β‐Cyclodextrin
Authors: Legrand François‐Xavier , Six Natacha , Slomianny Christian , Bricout Hervé , Tilloy Sébastien , Monflier Eric
Published: May 2011

A new triphenylphosphane based on a β‐cyclodextrin skeleton (PM‐β‐CD‐OTPP) was synthesized. This ligand can be dispersed in water by using the nanoprecipitation method. Transmission electron microscopy and NMR spectroscopy showed that PM‐β‐CD‐OTPP is aggregated in water and forms a stable dispersion. Its aqueous solubility can be dramatically increased in the presence of selected water‐soluble guests by formation of inclusion complexes. Associated to a rhodium precursor, PM‐β‐CD‐OTPP is able to generate soluble rhodium species in water. In addition, NMR experiments showed that the cyclodextrin cavity remains accessible for a guest even when PM‐β‐CD‐OTPP is coordinated to rhodium. Finally, this ligand was efficient for rhodium‐catalyzed hydrogenation and hydroformylation performed in aqueous medium.
Ring Size‐Selective Ring‐Closing Olefin Metathesis: Taking Advantage of the Deleterious Effect of Ethylene Gas
Authors: Yoshida Kazuhiro , Kano Yuto , Takahashi Hidetoshi , Yanagisawa Akira
Published: May 2011

The deleterious effect of ethylene gas on the ring‐closing olefin metathesis (RCM) for the formation of 5‐ to 8‐membered rings was investigated. Significant rate differences caused by ethylene gas were observed among the different ring‐size formation reactions. Nevertheless, the rate differences can be advantageously utilized for chemoselective RCM.
Asymmetric Aerobic Oxidation of α‐Hydroxy Acid Derivatives Catalyzed by Reusable, Polystyrene‐Supported Chiral N‐Salicylidene Oxidovanadium tert‐Leucinates
Authors: Salunke Santosh B. , Babu N.Seshu , Chen Chien‐Tien
Published: May 2011

The direct immobilization of two different C‐5‐propargyl ether‐modified, chiral N‐salicylidene vanadyl(V) tert‐leucinates onto 4‐azidomethyl‐substituted polystyrene by click chemistry was examined. Among the eight different solvents investigated, the resulting polystyrene‐supported catalysts promote the asymmetric, aerobic oxidation of α‐hydroxy (thio)esters and amides with enantioselectivities of up to 99% ee (selectivity factor up to 41) in chloroform. These polystyrene‐supported catalysts can be readily recovered by filtration and reused for at least four consecutive runs without discernible loss of reactivity and enantioselectivity.
Efficient Recovery and Reuse of an Immobilized Peptidic Organocatalyst
Authors: Arakawa Yukihiro , Wiesner Markus , Wennemers Helma
Published: May 2011

Readily reusable immobilized organocatalysts are important from a practical, economic, and environmental viewpoint. However, their successful development has proven challenging and only limited reaction and recovery cycles have been achieved. We report an extraordinarily robust resin‐bound tripeptidic organocatalyst that can be readily reused for at least 30 reaction and recovery cycles without loss in catalytic activity or stereoselectivity. The immobilized catalyst can be directly reused for conjugate addition reactions between aldehydes and nitroolefins after a simple filtration from the reaction products. The catalytic efficiency and chemoselectivity of the immobilized peptidic catalysts is so high that a broad range of γ‐nitroaldehydes were isolated easily after filtration and removal of all volatiles in quantitative yields, excellent diastereoselectivities and enantioselectivities and, most remarkably, perfect analytical purities. The ease of handling allows for a facile scale‐up of reactions catalyzed by the immobilized peptidic catalyst. In addition, the results provide a guide for the further development of immobilized organocatalysts.
Brief communication: The relation between standard error of the estimate and sample size of histomorphometric aging methods
Authors: Hennig Cheryl , Cooper David
Published: May 2011

Histomorphometric aging methods report varying degrees of precision, measured through Standard Error of the Estimate (SEE). These techniques have been developed from variable samples sizes (n) and the impact ofnon reported aging precision has not been rigorously examined in the anthropological literature. This brief communication explores the relation betweennand SEE through a review of the literature (abstracts, articles, book chapters, theses, and dissertations), predictions based upon sampling theory and a simulation. Published SEE values for age prediction, derived from 40 studies, range from 1.51 to 16.48 years (mean 8.63; sd: 3.81 years). In general, these values are widely distributed for smaller samples and the distribution narrows asnincreases—a pattern expected from sampling theory. For the two studies that have samples in excess of 200 individuals, the SEE values are very similar (10.08 and 11.10 years) with a mean of 10.59 years. Assuming this mean value is a ‘true’ characterization of the error at the population level, the 95% confidence intervals for SEE values from samples of 10, 50, and 150 individuals are on the order of ±4.2, 1.7, and 1.0 years, respectively. While numerous sources of variation potentially affect the precision of different methods, the impact of sample size cannot be overlooked. The uncertainty associated with SEE values derived from smaller samples complicates the comparison of approaches based upon different methodology and/or skeletal elements. Meaningful comparisons require larger samples than have frequently been used and should ideally be based upon standardized samples. Am J Phys Anthropol, 2011. © 2011 Wiley‐Liss, Inc.
Light Microscopy with Doughnut Modes: A Concept to Detect, Characterize, and Manipulate Individual Nanoobjects
Authors: Züchner Tina , Failla Antonio Virgilio , Meixner Alfred J.
Published: May 2011

Higher order laser modes, mainly called doughnut modes (DMs) have use in many different branches of research, such as, bio‐imaging, material science, single‐molecule microscopy, and spectroscopy. The main reason of their increasing importance is that recently, the techniques to generate well‐defined DMs have been refined or rediscovered. Although their potential is still not fully utilized, their specifically polarized field distribution gives rise to a wide field of applications. They are contributing to complete our fundamental knowledge of the optical properties of single emitting species, such as molecules, nanoparticles, or quantum dots, offering insight into the three‐dimensional dipole or particle orientation in space. The perfect zero intensity in the focus center qualifies some DMs for stimulated emission depletion (STED) microscopy. For the same reason, they have been suggested for trapping and tweezing applications.
Cyclometalated iridium(III) complex of 6‐hydroxydipyrido[3,2‐a:2′,3′‐c]phenazine: synthesis, and acid–base and avid DNA binding properties
Authors: Chen Yan‐Min , Zhang An‐Guo , Wang Ke‐Zhi
Published: May 2011

A new cyclometalated Ir(III) complex [Ir(ppy)2(hdppz)]PF6 (Hppy = 2‐phenylpyridine and hdppz = 6‐hydroxydipyrido[3,2‐a:2′,3′‐c]phenazine) was synthesized and characterized. The pH effects on the UV–vis absorption spectra were studied and ground‐state acid ionization constant pKa values of the complex were derived. The calf thymus DNA (ct‐DNA) binding properties of the complex were investigated with UV‐vis absorption spectrophotometric titrations, DNA competitive binding with ethidium bromide, DNA melting experiments, viscosity measurements and density functional theory (DFT) calculations. The complex was demonstrated to act as a ct‐DNA intercalator with a large DNA binding constant value of (6.06 ± 0.32) × 106 M−1 in 50 mM NaCl. The avid DNA binding affinity observed was rationalized by the DFT calculations. Copyright © 2011 John Wiley & Sons, Ltd.
Burden and viability of Borrelia burgdorferi in skin and joints of patients with erythema migrans or lyme arthritis
Authors: Li Xin , McHugh Gail A. , Damle Nitin , Sikand Vijay K. , Glickstein Lisa , Steere Allen C.
Published: May 2011

Objective

To determine the burden and viability of Borrelia burgdorferi in the skin and joints of patients with Lyme disease.

Methods

Standard and quantitative polymerase chain reaction (PCR) techniques were used to detect B burgdorferi DNA in skin samples from 90 patients with erythema migrans (EM) and in synovial fluid (SF) from 63 patients with Lyme arthritis (LA) and in synovial tissue from 9 patients. Quantitative PCR determinations of B burgdorferi DNA, messenger RNA (mRNA), and ribosomal RNA (rRNA) were made in 10 skin samples from EM patients and 11 SF samples from LA patients.

Results

Skin lesions in most patients with EM had positive PCR results for B burgdorferi DNA. In the majority of patients with LA, a late disease manifestation, PCR results in pretreatment SF samples were positive. In patients with antibiotic‐refractory arthritis, positive PCR results persisted for as long as 11 months, but positive results in samples taken during the postantibiotic period did not correlate with relapse or with the subsequent duration of arthritis, and at synovectomy, all results of PCR of synovial tissue were negative. B burgdorferi mRNA, a marker of spirochetal viability, was detected in 8 of 10 skin samples from EM patients, but in none of 11 SF samples from LA patients, even when obtained prior to antibiotic administration. Moreover, the median ratio of spirochetal rRNA to DNA, a measure of ribosomal activity, was 160 in the 10 EM skin samples, but only 0.15 in the 3 LA SF samples with positive results.

Conclusion

B burgdorferi in the skin lesions of EM patients were active and viable, whereas those in the SF of LA patients were moribund or dead at any time point. Thus, detection of B burgdorferi DNA in SF is not a reliable test of active joint infection in Lyme disease.
Anatomical Sciences Education Vol. 4, Issue 3, 2011 Cover Image
Authors: Macchi Veronica , Porzionato Andrea , Stecco Carla , Tiengo Cesare , Parenti Anna , Cestrone Adriano , De Caro Raffaele
Published: May 2011

Medical Gross Anatomy lecture at the University of Padova, Italy. Gross Anatomy at the University of Padova is taught utilizing both traditional and technological resources, which are integrated with practical laboratory exercises (mainly on plastic models and plastinated specimens) as well as radiological anatomy. In this issue of ASE, Dr. Veronica Macchi and her colleagues from the Department of Human Anatomy and Physiology at the University of Padova discuss an innovative pilot project with their University Hospital in which they obtain body parts removed from patients during surgical procedures and utilize them for gross anatomy education. The cover photograph shows one of the co‐authors of this paper, Professor Raffaele De Caro and his students, performing dissection of the distal forearm and hand in the anatomy lecture theater at the University of Padova.
Coverage‐Dependent Variation of Adsorption Configurations of Methionine on Ge(100)
Authors: Yang Sena , Kim Yaewon , Park Sunmin , Kim Ki‐jeong , Lee Hangil
Published: May 2011

The adsorption configurations of methionine molecules on the Ge(100) surface have been studied by using DFT calculations, core‐level photoemission spectroscopy (CLPES), and low‐energy electron diffraction (LEED) to scrutinize the adsorption structure as a function of coverage. At first, we obtained two important and stable structures. One is the most stable structure between these structures described as an “OH dissociated‐N dative‐S dative‐bonded structure” and the other is a less stable adsorption structure of these indicating an “OH dissociated‐S dative‐bonded structure” by using DFT calculations. We also performed CLPES to clarify our DFT calculation results. Through the spectral analysis of the S 2p, C 1s, N 1s, and O 1s core‐level spectra, we acquired the reasonable results that also revealed quite different bonding configurations depending on the methionine coverage. At low coverage (ca. 0.30 ML), a single type of sulfur and charged nitrogen peaks, which indicate an “OH dissociated‐N dative‐S dative‐bonded structure”, were observed. On the other hand, two types of sulfur peaks with thiol formation and two nitrogen peaks with neutralized and charged characteristics were monitored at a higher coverage (0.60 ML and above), which can be described as an “OH dissociated‐S dative‐bonded structure”. Hence, we can clearly demonstrate that our results obtained from CLPES spectra and DFT calculations are matched well with each other. Moreover, we additionally confirmed that the relative population of the two types of thiols and amines being included in methionine in between half monolayer induces a surface reorientation in the ordering from 2×1 to 1×1 employing LEED. This interesting variation of the methionine adsorbed on the Ge(100) surface by coverage dependence will be precisely discussed by using DFT calculations, CLPES, and LEED.
Why is it crucial to reintegrate pathology into cancer research?
Authors: Rodriguez‐Canales Jaime , Eberle Franziska C. , Jaffe Elaine S. , Emmert‐Buck Michael R.
Published: May 2011

The integration of pathology with molecular biology is vital if we are to enhance the translational value of cancer research. Pathology represents a bridge between medicine and basic biology, it remains the gold standard for cancer diagnosis, and it plays an important role in discovery studies. In the past, pathology and cancer research were closely associated; however, the molecular biology revolution has shifted the focus of investigators toward the molecular alterations of tumors. The reductionist approach taken in molecular studies is producing great insight into the inner workings of neoplasia, but it can also minimize the importance of histopathology and of understanding the disease as a whole. In turn, pathologists can underestimate the role of molecular studies in developing new ancillary techniques for clinical diagnosis. A multidisciplinary approach that integrates pathology and molecular biology within a translational research system is needed. This process will require overcoming cultural barriers and can be achieved through education, a more effective incorporation of pathology into biological research, and conversely an integration of biological research into the pathology laboratory.
Metal ion‐assembled micro‐collagen heterotrimers
Authors: LeBruin Lyndelle Toni , Banerjee Sunandan , O'Rourke Bruce Delany , Case Martin Ashley
Published: May 2011

Collagen mimetic peptides (CMPs) provide critical insight into the assembly, stability, and structure of the triple helical collagen protein. The majority of natural fibrous collagens are aab or abc heterotrimers, yet few examples of heterotrimeric CMPs have been reported. Previously, CMP heterotrimers have only been accessible by total syntheses or by introducing complementary interstrand electrostatic or steric interactions. Here, we describe an abc CMP heterotrimer in which each contributing CMP consists of only three amino acids: glycine, proline and 4‐hydroxyproline. Assembly of the heterotrimeric triple helix is directed by a combination of metal‐ion coordination to set the relative register of the CMPs, and minimization of valence frustration to direct heterotrimerization. Assembly of the four‐component mixture is facile and extremely rapid, and equilibration to the abc heterotrimer occurs within a few hours at modestly elevated temperatures. The melting temperatures of the metal‐assembled collagen trimers are higher by some 30°C than the apopeptide assemblies. Two iterations of the design are described, and the outcomes suggest possibilities for designing self‐assembling abc and abb heterotrimers. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 792‐800, 2011.
Inhibitory effects of novel integrin‐targeting peptides on angiogenesis activity in HUVEC cells in vitro
Authors: Liu Yaqin , Li Yesen , Xu Yuhong
Published: May 2011

Integrins are critically involved in many tumour‐promoting activities. The development of inhibitors against integrins may suppress tumour growth by inhibiting tumour angiogenic signalling. In this study, we investigated the effects of two novel peptides containing the integrin binding arginine‐glycine‐aspartic acid‐motif on inhibiting diverse cell behaviours, including cell adhesion, motility, invasion, tube formation and cell cytoskeleton. Cell adhesion and motility assays demonstrated that cyclopeptides c‐Gly and c‐Lys might inhibit the adhesive and motile activity at the concentration of 25 μM. There was no significant effect on cell invasion, indicating the importance of extracellular matrix degradation in modulating the anti‐invasive effect of human umbilical vein endothelial cells (HUVECs). More importantly, the tubular network formation of HUVECs was significantly inhibited by cyclopeptide c‐Lys besides causing a remarkable inhibition of cytoskeletal organization, disrupting the focal adhesion and actin stress fibres formation. In conclusion, this study results indicated that the novel peptide c‐Lys has the ability to inhibit diverse cell behaviours of HUVECs, and the effects may be mediated at different levels of the tumour growth. Therefore, c‐Lys is perhaps proposed to be a potent anti‐angiogenic drug candidate. Copyright © 2011 John Wiley & Sons, Ltd.
The Sintering of Supported Pd Automotive Catalysts
Authors: Xu Qing , Kharas Karl C. , Croley Brandon J. , Datye Abhaya K.
Published: May 2011

This work is directed at investigating the contribution of metal particle sintering to catalyst deactivation in close‐coupled automotive catalysts that are aged at elevated temperatures. We focus on the evolution of metal particle sizes in Pd/Al2O3 under conditions typically used for accelerated aging of automotive exhaust catalysts (10 mol % H2O at 900 °C). By using multiple analytical techniques (transmission electron microscopy, X‐ray diffraction, chemisorption, and CO oxidation) we can determine the role of support surface area collapse (encapsulation) versus metal particle sintering. The final dispersion (% metal atoms exposed) after sintering for 96 h ranged from 1.94 to 0.86 % for metal loadings ranging from 0.1 to 7.0 wt % (a 70‐fold variation). Thus, it appears that metal loading (over the range studied) has only a limited effect on the final dispersion in the sintered catalyst. The sintering kinetics were found to obey a relationship dn−${d{{n\hfill \atop 0\hfill}}}$=kt for which the exponent n is approximately 2.0 and d is the number average particle diameter at time t. This relationship and the fact that metal particle size continues to grow with time are both consistent with Ostwald ripening as the dominant mechanism. Furthermore, no limiting (equilibrium) particle size was achieved within the sintering times studied here (up to 200 h). These results have important implications for the design of thermally stable automotive catalysts.
NMR Spectroscopy of Intermetallic Compounds: An Experimental and Theoretical Approach to Local Atomic Arrangements in Binary Gallides
Authors: Haarmann Frank , Koch Katrin , Jeglič Peter , Pecher Oliver , Rosner Helge , Grin Yuri
Published: May 2011

The results of the investigation of MGa2 with M=Ca, Sr, Ba and of MGa4 with M=Na, Ca, Sr, Ba by a combined application of NMR spectroscopy and quantum mechanical calculations are comprehensively evaluated. The electric‐field gradient (EFG) was identified as the most reliable measure to study intermetallic compounds, since it is accessible with high precision by quantum mechanical calculations and, for nuclear spin I>1/2, by NMR spectroscopy. The EFG values obtained by NMR spectroscopy and quantum mechanical calculations agree very well for both series of investigated compounds. A deconvolution of the calculated EFGs into their contributions reveals its sensitivity to the local environment of the atoms. The EFGs of the investigated di‐ and tetragallides are dominated by the population of the px‐, py‐, and pz‐like states of the Ga atoms. A general combined approach for the investigation of disordered intermetallic compounds by application of diffraction methods, NMR spectroscopy, and quantum mechanical calculations is suggested. This scheme can also be applied to other classes of crystalline disordered inorganic materials.
Hemoglobin as a Nitrite Anhydrase: Modeling Methemoglobin‐Mediated N2O3 Formation
Authors: Hopmann Kathrin H. , Cardey Bruno , Gladwin Mark T. , Kim‐Shapiro Daniel B. , Ghosh Abhik
Published: May 2011

Nitrite has recently been recognized as a storage form of NO in blood and as playing a key role in hypoxic vasodilation. The nitrite ion is readily reduced to NO by hemoglobin in red blood cells, which, as it happens, also presents a conundrum. Given NO’s enormous affinity for ferrous heme, a key question concerns how it escapes capture by hemoglobin as it diffuses out of the red cells and to the endothelium, where vasodilation takes place. Dinitrogen trioxide (N2O3) has been proposed as a vehicle that transports NO to the endothelium, where it dissociates to NO and NO2. Although N2O3 formation might be readily explained by the reaction Hb‐Fe3++NO2−+NO⇌Hb‐Fe2++N2O3, the exact manner in which methemoglobin (Hb‐Fe3+), nitrite and NO interact with one another is unclear. Both an “Hb‐Fe3+‐NO2−+NO” pathway and an “Hb‐Fe3+‐NO+NO2−” pathway have been proposed. Neither pathway has been established experimentally. Nor has there been any attempt until now to theoretically model N2O3 formation, the so‐called nitrite anhydrase reaction. Both pathways have been examined here in a detailed density functional theory (DFT, B3LYP/TZP) study and both have been found to be feasible based on energetics criteria. Modeling the “Hb‐Fe3+‐NO2−+NO” pathway proved complex. Not only are multiple linkage‐isomeric (N‐ and O‐coordinated) structures conceivable for methemoglobin–nitrite, multiple isomeric forms are also possible for N2O3 (the lowest‐energy state has an NN‐bonded nitronitrosyl structure, O2NNO). We considered multiple spin states of methemoglobin–nitrite as well as ferromagnetic and antiferromagnetic coupling of the Fe3+ and NO spins. Together, the isomerism and spin variables result in a diabolically complex combinatorial space of reaction pathways. Fortunately, transition states could be successfully calculated for the vast majority of these reaction channels, both MS=0 and MS=1. For a six‐coordinate Fe3+‐O‐nitrito starting geometry, which is plausible for methemoglobin–nitrite, we found that N2O3 formation entails barriers of about 17–20 kcal mol−1, which is reasonable for a physiologically relevant reaction. For the “Hb‐Fe3+‐NO+NO2−” pathway, which was also found to be energetically reasonable, our calculations indicate a two‐step mechanism. The first step involves transfer of an electron from NO2− to the Fe3+–heme–NO center ({FeNO}6) , resulting in formation of nitrogen dioxide and an Fe2+–heme–NO center ({FeNO}7). Subsequent formation of N2O3 entails a barrier of only 8.1 kcal mol−1. From an energetics point of view, the nitrite anhydrase reaction thus is a reasonable proposition. Although it is tempting to interpret our results as favoring the “{FeNO}6+NO2−” pathway over the “Fe3+‐nitrite+NO” pathway, both pathways should be considered energetically reasonable for a biological reaction and it seems inadvisable to favor a unique reaction channel based solely on quantum chemical modeling.
Squaramides: Bridging from Molecular Recognition to Bifunctional Organocatalysis
Authors: Alemán José , Parra Alejandro , Jiang Hao , Jørgensen Karl Anker
Published: May 2011

In this minireview, squaramides are presented from their roots as artificial anion receptors in molecular recognition studies to their recent advances as powerful bifunctional hydrogen‐bonding catalysts in asymmetric organocatalysis. The main features of the squaramido functionality and the direct comparison with the analogous ureas and thioureas are also discussed.
Proton‐Induced Tuning of Metal–Metal Communication in Rack‐Type Dinuclear Ru Complexes Containing Benzimidazolyl Moieties
Authors: Kobayashi Katsuaki , Ishikubo Masamichi , Kanaizuka Katsuhiko , Kosuge Keiko , Masaoka Shigeyuki , Sakai Ken , Nozaki Koichi , Haga Masa‐aki
Published: May 2011

Ru complexes bearing a bis‐tridentate benzimidazolyl ligand have been synthesized. The dinuclear ones act as a bibasic acid with pKa1=4.36 and pKa2=5.90. The protonated form of the dinuclear complex exhibited two one‐electron oxidations at +0.91 and +1.02 V versus the ferrocenium/ferrocene (Fc/Fc+) couple (the potential difference (ΔE)=0.11 V), but the di‐deprotonated form showed two waves at +0.50 and +0.58 V versus Fc/Fc+ (ΔE=0.08 V). Since the potential difference between two waves reflects the strength of the metal–metal interaction, the deprotonation of the benzimidazole moieties in the complexes weakened the Ru–Ru communication. The degree of electronic coupling between two metal centers, estimated from the intervalence charge transfer (IVCT) band, was greater for the protonated form. DFT calculations for the protonated and deprotonated forms of the dinuclear complex suggest that the RuII–L(H2) π* interaction plays a key role in the Ru–Ru interaction.
Open‐Shell Characters and Second Hyperpolarizabilities of One‐Dimensional Graphene Nanoflakes Composed of Trigonal Graphene Units
Authors: Yoneda Kyohei , Nakano Masayoshi , Fukui Hitoshi , Minami Takuya , Shigeta Yasuteru , Kubo Takashi , Botek Edith , Champagne Benoît
Published: May 2011

The impact of topology on the open‐shell characters and the second hyperpolarizabilities (γ) has been addressed for one‐dimensional graphene nanoflakes (GNFs) composed of the smallest trigonal graphene (phenalenyl) units. The main results are: 1) These GNFs show not only diradical but also multiradical characters when increasing the number of linked units. 2) GNFs composed of an equivalent number of units can exhibit a wide range of open‐shell characters—from nearly closed‐shell to pure multiradical characters—depending on the linking pattern of the trigonal units. 3) This wide variation in open‐shell characters is explained by their resonance structures and/or by their (HOMO−i)−(LUMO+i) gaps deduced from the orbital correlations. 4) The change in the linking structure of the units can effectively control their open‐shell characters as well as their γ values, of which the longitudinal components are significantly enhanced for the singlet GNFs having intermediate open‐shell characters. 5) Singlet alternately linked (AL) systems present intermediate multiradical characters even in the case of a large number of units, which creates a significant enhancement of γ with increasing the size, whereas nonalternately linked (NAL) systems, which present pure multiradical characters, possess much smaller γ values. Finally 6) by switching from the singlet to the highest spin states, the γ values of NAL systems hardly change, whereas those of AL systems exhibit large reductions. These fascinating structure–property relationships between the topology of the GNFs, their open‐shell characters, and their γ values not only deepen the understanding of open‐shell characters of GNFs but aim also at stimulating further design studies to achieve giant NLO responses based on open‐shell graphene‐like materials.