bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation into the Impacts of Varied Batches of Stripped Eggs on the Reproductive Success of Clarias gariepinus
Authors: Otoh, A. J.  , George, U. U.  , Asangusung, P. S.  , Okoko, A. C.  , Ekanem, I. E.  , Umaha, M. N.  
Published: March 2024

This study was conducted at the hatchery complex of Akwa Ibom State University to investigate the effects of different batches of stripped egg on reproductive performances of Clarias gariepinus. Nine brood stocks of Clarias gariepinus (six males and 3 females) with average body weight of 2.3kg and 64.2 cm where carefully selected for the study. Six matured males were euthanized for the removal of testis without hormonal inducements. The milt collected from the six males were pooled together and divided into 12 portions each diluted with 2mL of normal saline solution. Three female brood stocks where separately induced with hormone at single dosage of 0.5ml/kg body weight and allowed for a period of 10 hours before stripping. Stripping of eggs from each brood stock where in four batches, each batch measured 50g and labeled A, B, C and D. 3g of eggs containing approximately 2000 oocytes (eggs) where measured out from each batch and mixed with the diluted milt and incubated in a 2 x 1 x 10cm3 of water in a concrete pond at temperature of 26oC in three replicates. The result revealed that the reproductive performances considered in this study decreased as the batches of stripped eggs increased from 1 ̶ 4 batches. The first batch of stripped eggs produced 87.69 ± 0.42, 97.06 ± 0.84, 84.29 ± 1.05 percentage fertilization, hatchability and survival rate respectively, while the least batch of stripped eggs (batch 4) produced the least value of fertilization 50.33 ± 1.67, 31.93 ± 4.94 hatchability and survival rate value of 42.69 ± 0.61. Therefore, from the above result, the least batch of stripped eggs should not be used for fertilization because the unhatched or dead eggs has a negative effect on the fertilized eggs including fry at the hatchery level.
Characterisation, Conservation and Sustainable Utilization of Kombai Dog Breed: A Unique Genetic Resource of India
Authors: Selvam R. , Rajinikanth V. , Satheeshkumar P. , Priyadharsini R. , Jagatheesan P.N. Richard 
Published: March 2024

Kombai is an ancient dog breed of Tamil Nadu, India. The Kombai dog is renowned for its fierce loyalty to its family and aggressiveness towards its adversaries. They are incredibly powerful, extremely intelligent, courageous, protective, resilient, territorial, and amiable breed making them as excellent guard dogs. Other names of this breed are Indian/Tamil Bear Hound, Poligar Dog, Mandai War Dog and Indian Rottweiler. The significant feature of this breed is that it lacks a fierce bark, it barks infrequently. Kombai is a sight hound, it hunt by sight and speed rather than by scent and stamina. The breed originated from the foothills of the Western Ghats in Theni district, Tamil Nadu. The breeding tract of this dog are Kombai, Uthamapalaiyam, Pannaipuram, Thevaram, Periakulam, Bodinayakkanur, Cumbam and Kudalur of Theni district and consequently dispersed throughout the southern India. The variants of this breed are Pulicharai Kombai and Porr Kombai. Kombai is medium-sized dog with muscular physique. True to this type of breeds are tan, brown, or reddish brown in color with a black muzzle, hence it is called as “Karuvaisevalai” or “Karumunji naai”. Piebald and brindle coat types are less popular. The head of a Kombai dog appear to be slightly larger than the body as a whole. Large oval-shaped dark brown eyes, strong jaws, and a broad, deep chest characterize the Kombai, and it has single, uniform, dense coat that is neither patchy nor uneven. It has lean muscles and a ridge that runs the length of their spine in the opposite way strengthens the entire body. Their mid-length ears are mostly flat or fold over at the front or sometime erect. The legs are designed for agility and quickness. The tail has smooth hair and is long, curling at the edge like a sickle. An adult dog weigh up to 30kg (Male 25–32 kg; Female 20–25 kg) and 24 inches in height (Males: 22 to 24 inches; Females:19 to 22 inches). Average life span of this breed is 12-15years. Litter size is 4 to 6. Kombai dogs attain sexual maturity between 6-10 months. At present, the Kombai breed is becoming scarce and is in danger of going extinct as a result of ban on hunting, indiscriminate breeding, lack of knowledge about their significance, and shortage of traditional breeders. It is imperative to take immediate action to conserve this superior distinctive genetic resource. Establishment of Kombai breeders association and proper coordination and integration among various agencies is highly needed. This unique Kombai dog should be conserved in their innate habitats by implementing partaking approach by including breeders, communities, and other pertinent shareholders in conservation programs and it should be registered as breed.
Numerical Evaluation of Vibration Induced by Explosive Blasting in the Bauxite Mines of Sangarédi, Guinea
Authors: Keita Oumar , Camara Yacouba 
Published: March 2024

During rocks blasting by explosives in mines and quarries, Vibration phenomena appear in the surrounding environment, often causing significant damage to neighboring structures such as: buildings, bridges, tunnels and dams. This is why mining companies using the technique of the explosion are often faced with constraints of limiting the vibration level in order to minimize or eliminate potential damage to neighboring structures or reduce neighbor complaints.
This paper presents a new numerical prediction model for vibration level induced by explosive blasting in the Bauxite mines of Sangarédi, Guinea. The dynamic damage law is associated with vibration phenomena analyses to determine numerical value of the particle velocities of different points located at different distances from the explosion hole for the explosion of a single charge hole, in order to compare to the vibration level required by the specifications of the Guinea mining company, which authorizes a vibration level of 10 mm/s in an inhabited area. The prediction of the vibration level gives particle velocities of 11m/s at a distance of 10 m from the explosion hole. Based on the results of the model, one could estimate that this required vibration level would be reached at a distance of 80 m from the blast hole.
Bioremediation of Diesel Fuel Contaminated Soil: Effect of Non Ionic Surfactants and Selected Bacteria Addition
Authors: Collina Elena , Lasagni Marina , Pitea Demetrio , Franzetti Andrea , Di Gennaro Patrizia , Bestetti Giuseppina 
Published: July 2007

AbstractAim of this work was to evaluate influence of two commercial surfactants and inoculum of selected bacteria on biodegradation of diesel fuel in different systems. Among alkyl polyethossilates (Brij family) and sorbitan derivates (Tween family) a first selection of surfactants was performed by estimation of Koc and Dafnia magna EC50 with molecular descriptor and QSAR model. Further experiments were conducted to evaluate soil sorption, biodegradability and toxicity. In the second part of the research, the effect of Brij 56, Tween 80 and selected bacteria addition on biodegradation of diesel fuel was studied in liquid cultures and in slurry and solid phase systems. The latter experiments were performed with diesel contaminated soil in bench scale slurry phase bioreactor and solid phase columns. Tween 80 addition increased the biodegradation rate of hydrocarbons both in liquid and in slurry phase systems. Regarding the effect of inoculum, no enhancement of biodegradation rate was observed neither in surfactant added nor in experiments without addition. On the contrary, in solid phase experiments, inoculum addition resulted in enhanced biodegradation compared to surfactant addition.
Highly Selective and Sensitized Spectrophotometric Determination of Iron (III) Following Potentiometric Study
Authors: Shokrollahi Ardeshir , Ghaedi Mehrorang , Rajabi Hamid Reza 
Published: July 2007

AbstractA simple, selective and sensitized spectrophotometric method for determination of trace amounts of Fe3+ ion in tap and waste water solutions has been described. The spectrophotometric determination of Fe3+ ion using Ferron in the presence of N,N‐Dodecytrimethylammonium bromide (DTAB) has been carried out. The Beer's law is obeyed over the concentration range of 0.05‐2.6 μg mL‐1 of Fe3+ ion with the relative standard deviation (RSD %) <0.2 % and the molar absorptivity of complexes in pH 3.5 is 3.8×103 L mol‐1 cm‐1.Potentiometric pH titration has been used for prediction of protonation constants of ferron, and evaluating its stoichiometry and respective stability constant with Fe3+ ion. As it is obvious the most likely species of ferron alone and its complexes are LH (log=7.64), LH2 (logK=10.52), LH3 (logK=11.74) and ML2 (logβ= 23.68), ML3 (logβ= 23.68), ML3H (logβ= 23.68), ML3H2 (logβ= 23.68) and ML(OH)2 (logβ=23.68) respectively.
Parafac and PLS Applied to Determination of Captopril in Pharmaceutical Preparation and Biological Fluids by Ultraviolet Spectrophotometry
Authors: Niazi Ali , Ghasemi Nahid 
Published: July 2007

AbstractA new ultraviolet spectrophotometric method has been developed for the direct qualitative determination of captopril in pharmaceutical preparation and biological fluids such as human plasma and urine samples. The method was accomplished based on parallel factor analysis (PARAFAC) and partial least squares (PLS). The study was carried out in the pH range from 2.0 to 12.8 and with a concentration from 0.70 to 61.50 μg ml‐1 of captopril. Multivariate calibration models PLS at various pH and PARAFAC were elaborated from ultraviolet spectra deconvolution and captopril determination. The best models for this system were obtained with PARAFAC and PLS at pH = 2.04 (PLS‐PH2). The applications of the method for the determination of real samples were evaluated by analysis of captopril in pharmaceutical preparations and biological (human plasma and urine) fluids with satisfactory results. The accuracy of the method, evaluated through the root mean square error of prediction (RMSEP), was 0.58 for captopril with PARAFAC and 0.67 for captopril with PLS‐PH2 model. Acidity constant of captopril at 25 °C and ionic strength of 0.1 M have also been determined spectrophotometrically. The obtained pKa values of captopril are 3.90 ± 0.05 and 10.03 ± 0.08 for pKa1 and pKa2, respectively.
Heavy Metal Levels and Physico – Chemical Quality of Potable Water Supply in Warri, Nigeria
Authors: Nduka J.K.C. , Orisakwe O.E. 
Published: July 2007

AbstractThe interaction between man's activities and the environment is gaining world wide attention. Warri an oil producing community in Delta State of Nigeria is faced with environmental oil pollution. Since open and underground water bodies are regarded as final recipients of most environmental pollutants, this study sought to provide data on the levels of the physico‐chemical parameters and contaminants in Warri metropolitan water supply. This study investigated the cadmium, lead and chromium using Atomic Absorption Spectrophotometer, physico – chemical properties such as pH, temperature, total suspended solid TSS, total dissolved solid TDS, electrical conductivity EC, biological oxygen demand BOD, dissolved oxygen DO, chemical oxygen demand COD, and total coliform count of potable water sources in Warri. Ekpan River was found to have 1.2mg/L of cadmium, 1.0mg/L of chromium, 1.20mg/L of lead and 2.0mg/L of manganese. The heavy metals levels and the pollution parameters were lowest in the borehole water samples, except pH which is more acidic in borehole water samples and conductivity which is more in well water samples in all the sampling stations. Some of the parameters were above WHO standards.
Partitioning Study of Polycyclic Aromatic Hydrocarbons between Water and Some Selected Water‐Insoluble Phases
Authors: Ceraulo Leopoldo , Fanara Serena , Ferrugia Mirella , Turco Liveri Vincenzo 
Published: July 2007

AbstractAn investigation on the partitioning of naphthalene and phenanthrene between water and some water‐insoluble phases has been carried out by Uv‐vis‐NIR spectrophotometry. The analysis of the experimental results emphasized the role of intermolecular interactions and structural features of the hosting phases as driving forces of the partitioning of these polycyclic aromatic hydrocarbons. The critical comparison of the resulting distribution constants allowed to evaluate the potentials of some extracting phases to set up sensitive analytical methods and/or effective environment remediation technologies.
Highly Selective and Sensitive Spectrophotometric Determination of Trace Amounts of Silver Ion in Surfactant Media Using 2‐Mercaptobenzoxazole
Authors: Ghaedi M. , Daneshfar A. , Shokrollahi A. , Ghaedi H. , Arvin Pili F. 
Published: July 2007

AbstractA simple and accurate spectrophotometric method for determination of trace amounts of silver ion in tap and wastewater solution and photographic solutions has been described. The spectrophotometric determination of silver ion using 2‐mercaptobenzoxazole (MBO) in the presence of Triton X‐100 as nonionic surfactant has been carried out. The Beer's law is obeyed over the concentration range of 0.1‐9.0 μg mL‐1 of Ag+ ion with the detection limits of 1.6 ng mL‐1. The influence of type and amount of surfactant, pH, complexation time and amount of ligand on sensitivity of method were optimized. Finally the repeatability, accuracy and the effect of interfering ions on the determination of silver ion were evaluated. There is a good agreement between results of proposed method and atomic absorption spectrometry.
Simultaneous cyclic scheduling and optimal control of polymerization reactors
Authors: Terrazas‐Moreno Sebastian , Flores‐Tlacuahuac Antonio , Grossmann Ignacio E. 
Published: July 2007

AbstractThe simultaneous solution of the optimal sequencing and optimal dynamic transitions of two multigrade polymerization continuous stirred‐tank reactors (CSTRs) is presented. The simultaneous formulation leads to a mixed‐integer dynamic optimization (MIDO) problem. The profiles of the state variables during dynamic transitions are discretized using orthogonal collocation on finite elements, transforming the MIDO problem into a mixed‐integer nonlinear programming (MINLP) problem. The objective of this formulation is to maximize the profit of the manufacturing operation, considering polymer sales, inventory costs and transition costs. The transition cost term is determined by the duration of the transition stages and the manipulated variable profile during transitions. Two industrial reaction systems are used to analyze the optimal solution and compare it to other solutions obtained using different methods. Finally, a sensitivity analysis is carried out to describe the impact of changes in certain problem parameters. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Cyclisierungsreaktionen über Palladium‐katalysierte allylische Alkylierungen
Authors: Trost Barry M. 
Published: July 2007

AbstractDie historische Entwicklung der Chemie von Carbo‐ und Heterocyclen ist eng verknüpft mit ihrer Zugänglichkeit. Übergangsmetallkatalysierte Cyclisierungsreaktionen eröffnen neue Möglichkeiten zur einfachen Darstellung carbo‐ und heterocyclischer Verbindungen. Unter diesen Methoden nehmen Palladium‐katalysierte allylische Alkylierungen wegen ihrer außerordentlichen Chemo‐, Regio‐ und Diastereoselektivität sowie den sich abzeichnenden Möglichkeiten zur Entwicklung enantioselektiver Reaktionen einen hohen Stellenwert ein. Da der Ringschluß anderen Gesetzen unterliegt als in Reaktionen, die nicht übergangsmetallkatalysiert sind, lassen sich anstelle normaler (d. h. fünf‐, sechs‐ und siebengliedriger) Ringe bevorzugt mittlere (d. h. acht‐, neun‐, zehn‐ und elfgliedrige) und große Ringe aufbauen. Mit geeigneten Substraten kann man sogar Makrocyclen unter normalen Konzentrationsbedingungen darstellen. Ein weiterer Vorteil der übergangsmetallkatalysierten Substitution ist die – im Vergleich zu Reaktionen, die nicht übergangsmetallkatalysiert sind (Inversion der Konfiguration) – komplementäre Stereochemie (Retention der Konfiguration). Durch den vorübergehenden Einbau des Substrats in den Übergangsmetallkomplex kann im Übergangszustand eine stereochemische Anordnung erzwungen werden, die – unabhängig von der Stereochemie des Ausgangsmaterials – die Bildung des thermodynamisch weniger stabilen Produkts begünstigt. Während sich die meisten bisherigen Arbeiten auf die Synthese von Carbocyclen konzentrieren, stecken die Möglichkeiten zur Darstellung von Heterocyclen noch in den Anfängen. Heterocyclen können nicht nur durch C‐C‐Verknüpfung aufgebaut werden, sondern es können auch Heteroatome wie Sauerstoff und Stickstoff als Nucleophile bei der Cyclisierung fungieren; die Verwendung weiterer Heteroatome als Nucleophile bleibt zu untersuchen. Neue Anwendungsbereiche für Cyclisierungen durch allylische Alkylierung eröffnen sich, wenn man das benötigte π‐Allylpalladium‐Zwischenprodukt auf andere Weise als über Palladium (0)‐initiierte allylische Ionisierung erzeugt. Auch die Verwendung anderer Metalle anstelle von Palladium könnte weitere Möglichkeiten bieten.
Ungewöhnliche Geometrie eines sterisch gehinderten Analogons von (CH)
Authors: Maier Günther , Rang Harald , Kalinowski Hans‐Otto 
Published: July 2007

Möglicherweise trigonal‐bipyramidal liegt das tert‐Butyl‐substituierte Kation 1 vor. Wie 13C‐NMR‐Spektren zeigen, besteht ein temperaturabhängiges Gleichgewicht zwischen drei degenerierten Strukturen. Das Mittelungsspektrum entspricht der hochsymmetrischen Struktur 2.magnified image
Hexaalkinyltriphenylen als neuer Typ nematisch‐discotischer Kohlenwasserstoffe
Authors: Praefcke Klaus , Kohne Bernd , Singer Dirk 
Published: July 2007

Einen 80 (R = Pentyl) bzw. 54 K (R = Heptyl) breiten Mesophasenbereich weisen die hochungesättigten, großflächigen monotropen Kohlenwasserstoffe 1 auf, die durch repetitive Pd‐katalysierte Alkinylierung von Hexabromtriphenylen in einer Eintopfreaktion erhalten wurden. Wie bei anderen Multi(phenylethinyl)arenen mit ND‐Phasen sind auch hier die Umwandlungsenthalpien ΔH(ND → I) für den Klärvorgang mit etwa 0.2 kJ mol−1 auffallend klein.magnified image
Struktur und Farbe von substituiertem Pentaphenylbismut
Authors: Schmuck Arno , Pyykkö Pekka , Seppelt Konrad 
Published: July 2007

Die quadratisch‐pyramidale Struktur ist eine Ursache der intensiven Farbe von Pentaphenylbismut und vielen seiner Derivate wie 1. Die leichte elektronische Anregung wird in diesem Fall durch ein tiefliegendes LUMO ermöglicht, das nach der sechsten Koordinationsstelle des Oktaeders ausgerichtet ist. Bemerkenswert sind die mangelnde Abschirmung durch 4f‐Elektronen und relativistische Effekte. Das trigonal‐bipyramidale Derivat 2 ist nicht violett, sondern orange.magnified image
Lithium‐bis(di‐tert‐butylfluorsilyl)amid als Kontaktionenpaar mit linearer Si‐N⊖‐Si‐Einheit und als Ionenpaar ohne Li+‐Anion‐Kontakt
Authors: Pieper Ursula , Walter Simone , Klingebiel Uwe , Stalke Dietmar 
Published: July 2007

Wie wirken Donorsolventien auf die Titelverbindung ein? Die THF‐Verbindung liegt als Kontaktionenpaar 1 vor. Dagegen ermöglicht die stärkere Lewis‐Base [12] Krone‐4 erstmalig in einem derartigen System die Bildung freier Ionen 2.magnified image
Ein Carbonyleisen‐Komplex eines Amino‐9‐fluorenylidenborans mit Koordination an eine Borabutadien‐Einheit
Authors: Channareddy Sreelatha , Linti Gerald , Nöth Heinrich 
Published: July 2007

Im photochemisch erzeugten Tricarbonyleisen‐Komplex 1 von 9‐Fluorenyliden(tetramethylpiperidino)boran ist das Metallkomplex‐Fragment η4 an eine cis‐Borabutadien‐Einheit gebunden, wobei die Aromatizität eines Benzolringes stark gestört wird. Konsequenterweise reagiert der η4‐Komplex leicht mit Zweielektronen‐Donoren unter Bildung von η2‐Komplexen.magnified image
Gemischte Kolbe‐Elektrolysen mit Zuckercarbonsäuren
Authors: Weiper Andreas , Schäfer Hans J. 
Published: July 2007

Eine radikalische C‐C‐Verknüpfung von Zucker‐ und Alkylresten zu 3 gelang erstmals durch Elektrolyse von Gemischen aus Zuckercarbonsäuren wie 1 und Alkansäuren wie 2. In Abwesenheit der Alkansäuren spielen Radikalreaktionen nur eine untergeordnete Rolle.magnified image
Nickel: Ein Element mit vielfältigen Eigenschaften in der technisch‐homogenen Katalyse
Authors: Keim Wilhelm 
Published: July 2007

AbstractDer Stand und die Leistungsfähigkeit der Chemischen Industrie sind eng mit der Entwicklung der Katalyse verknüpft; es gibt Schätzungen, daß 60 bid 70% aller Industrie‐Chemikalien zu irgendeinem Zeitpunkt mit Katalysatoren in Kontakt kommen. In den vergangenen zwei Jahrzehnten ist der Marktanteil der homogenen Übergangsmetallkatalyse auf 10–15% gestiegen. Neben Cobalt, das vorzugsweise in der Hydroformylierung verwendet wird, ist Nickel das wohl am häufigsten technisch genutzte Metall. Vor allem Kohlenstoff‐Kohlenstoff‐Verknüpfungen können nickelkatalysiert mit hoher Selektivität durchgeführt werden. Hierzu zählen: Carbonylierungen; Ringsynthesen aus 1,3‐Dienen; Dimerisierungen, Oligomerisierungen, Polymerisierungen und Funktionalisierungen von Monoolefinen und Polyolefinen. Es ist das große Verdienst von Reppe und von Wilke, durch ihre Pionierarbeiten die homogene Nickelkatalyse in wesentlichen Bereichen erschlossen zu haben. Aber auch die Organonickel‐Chemie hat durch Wilke und seine Schule wichtige Impulse erfahren. Die Forschungen auf diesem Gebiet haben grundlegend zum Verständnis der während der Katalyse ablaufenden Reaktionen beigetragen. Nickelkatalysierte Reaktionen, die technisch durchgeführt werden oder von industriellem Interesse sind, stehen im Mittelpunkt dieses Beitrags; dabei wird auch auf mechanistische Aspekte eingegangen.
Carbonylierung doppelt lithiierter N‐Pivaloylanilin‐Derivate; ein neuer Weg zu Dioxindolen durch intramolekulare Abfangreaktion aromatischer Acyllithium‐Verbindungen
Authors: Smith Keith , Pritchard Gareth J. 
Published: July 2007

Einen neuen Zugang zu Indol‐Derivaten 3 bietet die Titelreaktion. Die bisher recht begrenzten Möglichkeiten, die Carbonylierung von Organolithium‐Verbindungen für Synthesen zu nutzen, werden wesentlich erweitert. Die doppelte Lithiierung von 1, Carbonylierung der Zwischenstufe bei Raumtemperatur und die abschließende Protonierung ergeben die Verbindungen 2, die problemlos in 3 umgewandelt werden können.magnified image
Abhängigkeit der anomeren Stabilisierung von der Struktur bei Acetalen
Authors: Beckhaus Hans‐Dieter , Dogan Barbara , Verevkin Sergej , Hädrich Johannes , Rüchardt Christoph 
Published: July 2007

Quantitative Aussagen über den anomeren Effekt bei Acetalen 1 wurden durch Gruppeninkremente möglich, die für das Schlüssel‐C‐Atom durch Vergleich der Bindungsenthalpien in Acetalen, Ethern und Kohlenwasserstoffen abgeleitet wurden. Die Extrastabilisierung durch den zweiten Sauerstoffsubstituenten ist überraschend groß und zeigt eine starke Substituentenabhängigkeit (Alkylphenylketonacetal ‐ 12.1, Formaldehydacetal ‐ 3.3 kcal mol‐1).magnified image
Erste direkte Nachweise der gehinderten Rotation unsubstituierter η5‐Cyclopentadienylgruppen in Lösung durch 13C‐NMR‐Spektroskopie
Authors: Mynott Richard , Lehmkuhl Herbert , Kreuzer Eva‐Maria , Joußen Eckhard 
Published: July 2007

Die Barriere ΔG# für die Rotation des Cp‐Rings in 1 beträgt bei ‐ 90°C 34.2 ± 1.5 kJ mol−1, wie aus den 13C‐NMR‐Spektren abgeleitet wurde. Die sterisch sehr anspruchsvollen übrigen Liganden dürften der Grund dafür sein, daß bei 1 und 2 die Rotation um die Cp‐M‐Bindung so stark gehindert ist, daß sie ab ca. ‐ 100°C auf der NMR‐Zeitskala langsam ist. Ersetzt man in 1 den Styroldurch einen Ethylenliganden, verändert sich das Cp‐13C‐NMR‐Signal bis ‐ 95°C nicht signifikant.magnified image