bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three‐Dimensional surgical anatomy for stapes surgery computer‐aided reconstruction and measurement
Authors: Takahashi Haruo , Sando Isamu 
Published: October 2006

AbstractTo define anatomical relationships relevant to stapes surgery, computer‐aided three‐dimensional reconstruction and measurement were performed on nine normal temporal bones. The mean distance from the inferior portion of the long process of the incus to the center of the oval window was 3.80 mm. The shortest distance from the center of the oval window to the utricular macula, saccular membrane, and macula averaged 1.37, 1.60, and 2.13 mm. Surgery directed posteromedial‐superior from the oval window was found to be most dangerous because it would come so close to the utricular macula; a pos‐teromedial‐inferior approach was found to be safest. The distance from the inferior margin of the oval window inferiorly to the cochlear duct in the hook portion ranged between 0.58 and 1.29 mm, suggesting that when a drill hole is made on the inferior margin of the oval window to lift up a depressed stapes footplate, the hole should not be greater than 0.5 mm in diameter.
Facial nerve to facial canal cross‐sectional area ratio in children
Authors: Saito Haruo , Takeda Taizo , Kishimoto Seiji 
Published: October 2006

AbstractThe incidence of facial palsy among children is lower than that among adults, and the recovery rate after facial palsy among children is higher than that of adults. To investigate these differences, we compared the cross‐sectional area ratio of the facial nerve to that of the facial canal in 26 pediatric temporal bone specimens with that of 10 adult temporal bone specimens. The ratios were 0.31 ±0.08,0.35 ±0.10, and 0.18 ± 0.12, respectively, in the labyrinthine, horizontal, and mastoid segments of pediatric specimens. The ratios for adult specimens were 0.46 ±0.07, 0.52 ± 0.17, and 0.37 ± 0.04, respectively, in the labyrinthine, horizontal, and mastoid segments. These ratios were all significantly smaller than those for the corresponding segments of the adult specimens (P<.01). The results indicate that in children there is less possibility for entrapment of the facial nerve in the facial canal, and that children require facial nerve decompression less often than adults.
Utility of immediate on‐site cytopathological procurement and evaluation in fine needle aspiration biopsy of head and neck masses
Authors: Eisele David W. , Koch Wayne M. , Richtsmeier William J. , Sherman Mark E. , Wu Agnes Y. , Erozan Yener S. 
Published: October 2006

AbstractThe utility of on‐site microscopic evaluation of fine needle aspirates (FNAs) of the head and neck was assessed by comparing the diagnostic yield in 336 specimens obtained with immediate on‐site cytopathological procurement and evaluation to that achieved in 548 cases performed without immediate on‐site evaluation. Three hundred six (91%) of 336 immediate evaluation specimens were adequate for cytopathologic diagnosis, compared to 391 (71%) of 548 specimens not evaluated immediately (P < .001, chi‐squared test). The higher satisfactory rate in immediate evaluation cases was related primarily to 1. immediate reaspiration of the masses until sufficient cytopathologic material was obtained for diagnosis; and 2. optimal specimen preparation.It is concluded that immediate on‐site cytopathological procurement and evaluation of fine needle aspirates of head and neck masses is a valuable practice which assures a higher yield of adequate specimens compared to biopsies taken without immediate evaluation. The technique of immediate on‐site evaluation of FNAs is discussed and a cost‐benefit analysis of immediate on‐site evaluation of FNAs is presented.
The extrinsic polyharmonic map heat flow in the critical dimension
Authors: Gastel Andreas 
Published: October 2006

Abstract
We consider the gradient flow of higher order elliptic functionals of the type ∫
M

2 for maps from a compact Riemannian manifold M to ℝ
n
with image contained in another compact manifold, called the extrinsic polyharmonic map heat flow. We prove that smooth initial values can be continued as an eternal solution to the flow if M is of dimension < 2m. In the critical case dim M = 2m, we find a unique eternal weak solution which is smooth except possibly for finitely many times. A singularity can occur only if a “bubble” separates, using up a certain amount of energy.
Evaluation of risk factors for development of secondary glaucoma in dogs: 156 cases (1999–2004)
Authors: Johnsen Devin A. J. , Maggs David J. , Kass Philip H. 
Published: October 2006

Abstract
Objective—To determine the immediately antecedent cause of secondary glaucoma and the prevalence of secondary glaucoma with anterior uveitis or lens dislocation in dogs.
Design—Retrospective case series.
Animals—156 dogs with secondary glaucoma.
Procedures—Cause of glaucoma was determined from records. Breed, age, sex, and neuter status of all dogs with secondary glaucoma were compared with the general hospital population. The prevalence of secondary glaucoma in dogs with a primary diagnosis of lens dislocation or anterior uveitis during the same period was determined.
Results—Secondary glaucoma was diagnosed in 156 of 2,257 (6.9%) dogs examined because of ophthalmic disease and was bilateral in 33 (21.2%) of those dogs. In 31 (94%) bilaterally affected dogs, the antecedent cause was the same in both eyes. Common causes of secondary glaucoma were non-surgical anterior uveitis (44.9%), anterior uveitis associated with prior phacoemulsification (15.8%), and lens dislocation (15.2%). Parson Russell Terriers, Poodles, Boston Terriers, Cocker Spaniels, Rhodesian Ridgebacks, and Australian Cattle Dogs had diagnoses of secondary glaucoma more often than expected, compared with the reference population. Age, sex, neuter status, and laterality were not associated with secondary glaucoma. The prevalence of secondary glaucoma in dogs with lens dislocation or uveitis was 15% or 17%, respectively.
Conclusions and Clinical Relevance—Glaucoma develops secondary to many intraocular diseases, particularly uveitis and lens dislocation. Diagnosis of these diseases should prompt frequent monitoring of intraocular pressure, regardless of signalment.
Effect of rostrocaudal mobility of the mandible on feed digestibility and fecal particle size in horses
Authors: Carmalt James L. , Allen Andrew L. 
Published: October 2006

Abstract
Objective—To evaluate the effect of rostrocaudal mobility (RCM) of the mandible during extension and flexion of the atlanto-occipital joint on weight gain, feed digestibility, and fecal particle size in horses.
Design—Randomized controlled trial.
Animals—34 pregnant mares housed in 1 barn.
Procedures—Horses were randomized into a treatment (n = 17) or control (17) group. All horses were sedated, and the distance between the rostral portions of the upper and lower incisor arcades was determined during extension and flexion of the atlanto-occipital joint; mandibular RCM was calculated as the difference between these values. In the treatment group, measurements were made after dental floating. Body weight was recorded 1 day before dental floating and at intervals after mandibular RCM determination for a period of 24 weeks. Feces were collected from each horse during two 5-day periods. Samples of feed and feces were analyzed to determine feed digestibility; particle size analysis was performed on dried fecal samples.
Results—Data obtained from each group of horses revealed that RCM of the mandible did not affect weight gain, feed digestibility, or particle size in feces; there were no differences among breeds. Controlling for age and number of dental lesions did not significantly affect results.
Conclusions and Clinical Relevance—In horses, RCM of the mandible did not appear to affect weight gain, feed digestibility, or fecal particle size. On the basis of these and other published data, the assumption that dental abnormalities affect digestion detrimentally in horses needs to be reevaluated.
Serum IgG and total protein concentrations in dairy calves fed two colostrum replacement products
Authors: Foster Derek M. , Smith Geof W. , Sanner Truman R. , Busso Gonzalo V. 
Published: October 2006

Abstract
Objective—To evaluate effects of 2 commercially available colostrum replacement products on serum IgG and total protein concentrations in dairy calves.
Design—Prospective clinical trial.
Animals—84 Holstein bull calves from a single dairy.
Procedures—Calves were randomly assigned to be given 4 quarts of colostrum (group 1; n = 21), 2 packages of a colostrum replacement product (product A; group 2; 21), 1 package of a different colostrum replacement product (product B; group 3; 21), or 2 packages of product B (group 4; 21). Treatments were given within 3 hours after birth, and blood samples were collected 24 hours later and submitted for determination of serum total protein and IgG concentrations.
Results—Group 1 calves had significantly higher serum total protein and IgG concentrations than did calves in the other 3 groups. However, the percentage of calves with adequate passive transfer (ie, serum IgG concentration > 1,000 mg/dL) was not significantly different among groups 1 (90%), 3 (81%), and 4 (95%). In contrast, only 10% of calves in group 2 had adequate passive transfer. It was predicted that calves fed product B that had serum total protein concentrations > 5.2 g/dL would have serum IgG concentrations > 1,000 mg/dL at least 90% of the time.
Conclusions and Clinical Relevance—Results indicated that product B could be considered as an alternative to colostrum in dairy calves, but product A failed to routinely provide adequate serum IgG concentrations when fed according to label directions.
3D numerical simulation of the flow of viscous newtonian and shear thinning fluids in a twin sigma blade mixer
Authors: Connelly Robin K. , Kokini Jozef L. 
Published: October 2006

AbstractThe flow and mixing in a 3D geometrically accurate representation of a twin sigma blade mixer is simulated using the finite element method (FEM) combined with the mesh superimposition technique as implemented by Polyflow (Fluent, Inc.) to calculate the velocity, velocity gradients, shear rates, and mixing index. The mixing conditions and material models are based on those used in the laser‐Doppler anemometry (LDA) experiments of Prakash and Kokini. The simulation results are analyzed to determine the effect of increasing shear thinning on the flow and mixing, and are also compared with the experimental results of Prakash and Kokini for the © 2006 Wiley Periodicals, Inc. Adv Polym Techn 25:182–194, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20071
Synthesis of New 1‐[5‐(Substituted Phenoxymethyl)‐1,3,4‐oxadiazol‐2‐yl]‐5‐(substituted benzylidene)hydantoins as Potential Anthelminthic Agents
Authors: Shukla Jagdish S. , Agarwal Km. Kanchan 
Published: October 2006

AbstractVarious 1‐[5‐(substituted phenoxymethyl)‐1,3,4‐oxadiazol‐2‐yl]5‐(substituted benzylidene)hydantoins have been synthesized. Their activities against Hymenolepis nana infection in rats were tested. Compound 27 was found to be the most active showing 78.0% clearance of infection at a dose of 250 mg/kg for 3 days.
Polarographische Simultanbestimmung von Nitrofurantoin und Phenazopyridin in Tabletten
Authors: Surmann Peter , Aswakun Penpan 
Published: October 2006

AbstractNitrofurantoin und Phenazopyridin liefern in geeignetem Puffer bei Verwendung der Differentiellen Puls Polarographie (DPP) gut ausgeprägte und voneinander separierte Peaks. Britton Robinson Puffer pH 5,5 hat sich als optimal erwiesen bezüglich Peakform und Basislinie. Wegen der hohen Empfindlichkeit eignet sich die Methode gut zur Bestimmung der content uniformity. Zwischen Peakhöhe und Konzentration besteht im Bereich 1 μg/ml bis 8 μg/ml Linearität. Dies gestattet eine Verdünnung, die Matrixeffekte durch die Tablettenhilfsstoffe unterdrückt.
1‐Acetyl‐2,4,5‐trimethyl‐3,6‐diazaphenanthrene
Authors: Gorlitzer Klaus , Buß Dietrich 
Published: October 2006

AbstractEs wird über die Darstellung der Titelverbindungen 3‐8, ausgehend vom 4‐(2‐Nitrophenyl)‐1,4‐dihydropyridin 1 oder dessen Photoprodukt 2, berichtet.
Thiophen als Strukturelement physiologisch aktiver Substanzen, 11. Mitt. Substituierte Thieno[2,3‐d]imidazole als potentiell antivirale Wirkstoffe
Authors: Binder Dieter , Noe Christian R. , Kollmann Hermann , Rosenwirth Brigitte 
Published: October 2006

AbstractEine neue Thieno[2,3‐d]imidazol‐Synthese wird beschrieben, wobei in der Schlüsselsequenz ein Nitrothiophenderivat mit Dinatriumcyanamid umgesetzt und das resultierende Natriumsalz nach einer katalytischen Hydrierung ringgeschlossen wird. Eine nach diesem Verfahren hergestellte Verbindung 1, deren Substitutionsmuster einem gegen Rhino‐ und andere Picornaviren hochwirksamen Benzolanalogon, dem Enviroxime (B), entspricht, zeigt eine geringere antivirale Aktivität als dieses.
3,6‐Diazaphenanthrene aus Nifedipin
Authors: Görlitzer Klaus , Buß Dietrich 
Published: October 2006

AbstractBei der fluorimetrischen Bestimmung von Nifedipin nach Schloßmann entsteht das Lactam 4a und das Hydroxamsäurehalbacetal 5a. Die Struktur von 4a wird durch die Verbindungen 7‐9, die Konfiguration und Konformation von 5a durch die Substanzen 5b sowie 11‐13 chemisch und spektroskopisch gesichert.
9‐Chlor‐3,6‐diazaphenanthrene aus Nifedipin
Authors: Görlitzer Klaus , Buß Dietrich 
Published: October 2006

AbstractDas durch photochemische Reaktion aus Nifedipin erzeugte Nitrosopyridin gibt mit konz. HCl das chlorhaltige 3,6‐Diazaphenanthren 3a. Der Eisen‐Komplex der Hydroxamsäure 3a ermöglicht eine spektralphotometrische Bestimmung für Nifedipin. 3 ergibt bei der Behandlung mit PCl3 das Lactam 4, mit Acetanhydrid das Hydroxamat 5.
1,4‐Pentadien‐3‐one, 23. Mitt. Zur Reaktion von 2,4‐Bis(methoxycarbonyl)‐1,5‐diaryl‐3‐thia‐1,4‐pentadienen sowie ihrer Sulfoxide und Sulfone mit Hydroxylamin
Authors: Yamamura Hiroko , Otto Hans‐Hartwig 
Published: October 2006

AbstractDie Titelverbindungen reagieren mit Hydroxylamin in Art einer doppelten Michael‐Addition zu 1,4‐Thiazinan‐Derivaten, deren Stereochemie diskutiert wird.
Zur Stereochemie der 3‐Oxo‐5‐phenyl‐1‐cyclopentancarbonsäuren, 6. Mitt. Chemo‐, Regio‐ und Stereoselektivität der Methylierung substituierter 2‐Cyclopentanon‐carbonsäureester
Authors: Körfer Inge , Frahm August W. 
Published: October 2006

AbstractEs wird die Chemo‐, Regio‐ und Stereoselektivität der Methylierung von r‐5‐(4‐Fluorphenyl)‐c‐2‐methyl‐3‐oxo‐1.1.t‐4‐cyclopentantricarbonsäure‐trimethylester (1) und r‐5‐(4‐Fluorphenyl)‐t‐2‐methyl‐3‐oxo‐1.1.t‐4‐cyclopentantricarbonsäure‐trimethylester (2) beschrieben. Aus 1 entstehen r‐5‐(4‐Fluorphenyl)‐3‐methoxy‐c‐2‐methyl‐3‐cyclopenten‐1.1.4‐tricarbonsäure‐trimethylester (3) und r‐5‐(4‐Fluorphenyl)‐c‐2‐methyl‐t‐4‐methyl‐3‐oxo‐1.1.c‐4‐cyclopentantricarbonsäure ‐trimethylester (4). Aus 2 wird zusätzlich zu 3 und 4 2.2‐Dimethyl‐r‐5‐(4‐fluorphenyl)‐3‐oxo‐1.1.t‐4‐cyclopentantricarbonsäure‐trimethylester (7) gebildet.
Reduktionen substituierter 3,7‐Diaza‐ und 3‐Thia‐7‐azabicyclo[3.3.1]nonan‐9‐one mit Natriumborhydrid
Authors: Haller Rolf , Ashauer Ulrike 
Published: October 2006

AbstractSubstituierte 3,7‐Diaza‐ und 3‐Thia‐7‐azabicyclo[3.3.1]nonan‐9‐ole werden durch Reduktion der entsprechenden Ketone mit Natriumborhydrid erhalten. Die Stereoselektivität der Reduktion ist in wäßrigem Dioxan sehr hoch, während in Methanol Epimerengemische entstehen. Die 1H‐NMR‐Spektren der epimeren Alkohole werden vergleichend diskutiert.
Tertiäre 3‐Oxa‐7‐azabicyclo[3.3.1]nonan‐9‐ole
Authors: Haller Rolf , Ashauer Ulrike 
Published: October 2006

AbstractVon substituierten 3‐Oxa‐7‐azabicyclo[3.3.1]nonan‐9‐onen abgeleitete tertiäre Alkohole werden durch Grignard‐Reaktion der Ketone mit Propargylmagnesiumbromid erhalten. Die Stereoselektivität dieser Reaktionen ist sehr hoch. 1H‐NMR‐ und IR‐Spektren werden diskutiert.
Synthesis of 1,5‐dihydro‐5‐(4‐methoxyphenyl)‐4H‐pyrazolo[3,4‐d]pyrimidin‐4‐ones and their ribosides and mannich bases
Authors: Finlander Peter , Pedersen Erik B. 
Published: October 2006

Abstract1,5‐Dihydro‐4H‐pyrazolo[3,4‐d]pyrimidin‐4‐ones 5 and 6 were prepared by reaction of the corresponding ethyl 5‐aminopyrazole‐4‐carboxylate with triethyl orthoformate and amines. Ethyl N‐(4‐methoxyphenyl)formimidate and N,N′‐bis(4‐methoxyphenyl)formamidine could also be used as the ring closing reagent. The Mannich bases 13 and 14 were produced in a reaction of 9 with formaldehyde and piperidine. The ribosides 15 were obtained by melting a mixture of 9 and 1,2,3,5‐tetra‐O‐acetyl‐β‐D‐ribofuranose in the presence of p‐toluenesulphonic acid.
Ein einstufiges Verfahren zur Darstellung von γ‐Yliden‐α,β‐butenoliden
Authors: Reisch Johannes , Mester Zita 
Published: October 2006

AbstractIn einem Eintopfverfahren können durch Umsetzung von Aldehyden bzw. deren Acetalen mit 2,5‐Dihydro‐2,5‐dimethoxy‐furan in Gegenwart von Trimethylchlorsilan γ‐Yliden‐α,β‐butenolide 3 dargestellt werden. Der Reaktionsmechanismus wird diskutiert.
Vinyloge Carbonsäuren vom 1,6‐Dihydropyridin‐Typ
Authors: Möhrle Hans , Reinhardt Hans W. 
Published: October 2006

AbstractAus C‐Aminomethylverbindungen von N‐sekundären Enaminonen entstehen mit Malon‐ oder Cyanessigestern unter Zusatz von Kalium‐tert.‐butylat die Kalium‐Salze vinyloger Carbonsäuren vom 1,6‐Dihydropyridin‐Typ. Der mehrstufige Reaktionsverlauf wird untersucht.
Selektive katalytische Hydrierungen und Hydrogenolysen, 6. Mitt. Eine verbesserte Synthese von 1‐Benzyl‐2‐methyloctahydroisochinolinen
Authors: Reimann Eberhard , Höglmüller Angelika 
Published: October 2006

AbstractDie Titelverbindungen 3 sind bequem aus den Methoiodiden 2 der entsprechenden Bz‐Tetrahydroisochinoline 1 durch NaBH4‐Reduktion herstellbar.
Chemical Stability of the Hagedorn Oximes HGG‐12 and HI‐6
Authors: Eyer Peter , Hell Winfried 
Published: October 2006

AbstractThe chemical stability of the soman antidotes HGG‐12 and HI‐6 was studied over the pH range 2–9 at various temperatures. Maximum stability for both oximes was found at pH 2. From Arrhenius plots the predicted shelf life (10% decomposition) was 2.6 years at 25° C and 60 years at 4 °C for both oximes. The apparent energy of activation was 113kJ/mol. The decay rate of both oximes apparently was not influenced by oxime concentration, buffer composition, light, and oxygen. By ion‐pair HPLC the following degradation products were indentified: pyridine‐2‐carbaldoxime, pyridine‐2‐carbonitrile, 2‐pyridone, formaldehyde and 3‐benzoylpyridine (for HGG‐12) or isonicotinamide and isonicotinic acid (for HI‐6). Two additional pyridinium compounds have not yet been identified. The pattern of degradation products varied considerably with pH.
Hydroxylamin‐Derivate der Quadratsäure
Authors: Zinner Gerwalt , Grünefeld Johann , Baehr Mitarbeit Von Michael 
Published: October 2006

AbstractReaktion von Quadratsäuredimethylester (1) mit äquimolaren Mengen substituierter Hydroxylamine ergibt 3‐Hydroxyamino‐4‐methoxy‐3‐cyclobuten‐1,2‐dione 2. Bei Umsetzung von Quadratsäuredichlorid mit Hydroxylaminen werden Desoxygenierungsreaktionen beobachtet.
National estimates and race/ethnic‐specific variation of selected birth defects in the United States, 1999–2001
Authors: Canfield Mark A. , Honein Margaret A. , Yuskiv Nataliya , Xing Jian , Mai Cara T. , Collins Julianne S. , Devine Owen , Petrini Joann , Ramadhani Tunu A. , Hobbs Charlotte A. , Kirby Russell S. 
Published: October 2006

AbstractBACKGROUND: In the United States, birth defects affect approximately 3% of all births, are a leading cause of infant mortality, and contribute substantially to childhood morbidity. METHODS: Population‐based data from the National Birth Defects Prevention Network were combined to estimate the prevalence of 21 selected defects for 1999–2001, stratified by surveillance system type. National prevalence was estimated for each defect by pooling data from 11 states with active case‐finding, and adjusting for the racial/ethnic distribution of US live births. We also assessed racial/ethnic variation of the selected birth defects. RESULTS: National birth defect prevalence estimates ranged from 0.82 per 10,000 live births for truncus arteriosus to 13.65 per 10,000 live births for Down syndrome. Compared with infants of non‐Hispanic (NH) white mothers, infants of NH black mothers had a significantly higher birth prevalence of tetralogy of Fallot, lower limb reduction defects, and trisomy 18, and a significantly lower birth prevalence of cleft palate, cleft lip with or without cleft palate, esophageal atresia/tracheoesophageal fistula, gastroschisis, and Down syndrome. Infants of Hispanic mothers, compared with infants of NH white mothers, had a significantly higher birth prevalence of anencephalus, spina bifida, encephalocele, gastroschisis, and Down syndrome, and a significantly lower birth prevalence of tetralogy of Fallot, hypoplastic left heart syndrome, cleft palate without cleft lip, and esophageal atresia/tracheoesophageal fistula. CONCLUSIONS: This study can be used to evaluate individual state surveillance data, and to help plan for public health care and educational needs. It also provides valuable data on racial/ethnic patterns of selected major birth defects. Birth Defects Research (Part A), 2006. © 2006 Wiley‐Liss, Inc.
Mechanism of Cycloisomerisation of 1,6‐Heptadienes Catalysed by [(tBuCN)2PdCl2]: Remarkable Influence of Exogenous and Endogenous 1,6‐ and 1,5‐Diene Ligands
Authors: Bray Katharine L. , Lloyd‐Jones Guy C. , Muñoz M. Paz , Slatford Paul A. , Tan Emily H. P. , Tyler‐Mahon Amanda R. , Worthington Paul A. 
Published: October 2006

AbstractThe mechanism of the highly regioselective cycloisomerisation of dimethyl hept‐1,6‐dienyl‐4,4‐dicarboxylate (1) by a neutral pre‐catalyst, [(tBuCN)2PdCl2] (8), to generate dimethyl 3,4‐dimethylcyclopent‐2‐ene‐1,1‐dicarboxylate (3) has been investigated by isotopic labelling (reactions involving single and mixed samples of 1,1,2,6,7,7‐[2H6]‐1; 3,3,5,5‐[2H4]‐1; 1,7‐(Z,Z)‐[2H2]‐1; [1,3‐13C1,5,7‐13C1]‐1 and [1,3‐13C1,6‐2H1]‐1) and by study of the reactions of dimethyl 1‐aryl‐hept‐1,6‐dienyl‐4,4‐dicarboxylates (9 a–e, where aryl is p‐C6H4‐X; X=H, OMe, Me, Cl, CF3) and dimethyl hept‐1,5‐dienyl‐4,4‐dicarboxylate (14), a 1,5‐diene isomer of 1. The mechanism proposed involves the generation of a monochloro‐bearing palladium hydride which undergoes a simple hydropalladation, carbopalladation, Pd/H dyotropy, β‐H elimination sequence to generate 3. A key point that emerges is that chelation of the 1,6‐diene 1 at various stages in the mechanism plays an important role in determining the regioselectivity of the reaction. The selective generation of 3 with pre‐catalysts of the form L2PdCl2, as compared to the generation of dimethyl 3‐methylene‐4‐methyl‐cyclopentane‐1,1‐dicarboxylate (2) with pre‐catalysts of the form [(MeCN)2Pd(allyl)]OTf (5) is ascribed to the absence of chloride ion in the latter, which makes an additional coordination site available throughout turnover. Liberation of the product 3 when [(tBuCN)2PdCl2] (8) is employed as pre‐catalyst, is proposed to proceed via a mono‐ to bidentate switch in the π‐coordination of diene 1 (η2 to bis‐η2) displacing π‐coordinated 3 from Pd. When 1‐aryl‐1,6‐dienes 9 are employed as substrates, the electron‐donor property of the aryl group is found to influence the regioselectivity of cyclisation. Electron‐withdrawing groups favour dimethyl 3‐arylmethyl‐4‐methylcyclopent‐2‐ene‐1,1‐dicarboxylates (10), whilst electron‐donating aryl groups favour 3‐arylidene‐4‐methyl‐cyclopentane‐1,1‐dicarboxylates (11). The regioselectivity (10/11) correlates with the Hammett σ+ values (ρ+=1.3, r 2=0.975) indicative of a strong π‐resonance contribution from the aryl ring rather than a simple σ‐inductive effect. Intermolecular modulation of regioselectivity is observed and the net effect proposed to arise through the (π→d) donation ability of the vinyl arene in the diene displacing product (10/11) via a mono‐ to bidentate switch in coordination. The isomerisation process increasingly sequesters Pd as turnover proceeds leading to a powerful inhibition mechanism and ultimately a limitation in turnover number to about 80.