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PubMed2006

Reactivity and structural and physical studies of tetranuclear iron(III) clusters containing the [Fe4(mu3-O)2]8+ "butterfly" core: an FeIII4 cluster with an S = 1 ground state.

The initial use of di-2-pyridyl ketone oxime [(py)2CNOH] in iron(III) carboxylate chemistry has yielded the tetranuclear complex [Fe4O2Cl2(O2CMe)2{(py)2CNO}4] (1). Compound 1 can be synthesized either by the 1:2:1 molar ratio reaction between Fe(III), MeCO2-, and (py)2CNOH (complex 1a) or by the 1:3 molar ratio reaction between [Fe3O(O2CMe)6(H2O)3]Cl and (py)2CNOH (complex 1b). The presence of N3- in both reaction mixtures has afforded the tetranuclear complex [Fe4O2(N3)2(O2CMe)2{(py)2CNO}4] (2), which can be alternatively synthesized by the reaction of 1 with N3-. Compound 1a crystallizes in the tetragonal space group /-4 with (at 25 degrees C) a = 35.06(2) A, b = 35.06(2) A, c = 13.255(6) A, V = 16293(2) A(3), and Z = 8. Compound 1b crystallizes in the monoclinic space group P2(1)/c with (at 25 degrees C) a = 22.577(7) A, b = 17.078(6) A, c = 17.394(6) A, beta = 93.50(1) degrees , V = 6694(4) A(3), and Z = 4. Compound 2 crystallizes in the triclinic space group P1 with (at 25 degrees C) a = 13.658(9) A, b = 15.815(9) A, c = 17.29(1) A, alpha = 97.08(3) degrees , beta = 98.55(3) degrees , gamma = 112.12(3) degrees , V = 3355(4) A(3), and Z = 2. The structures of 1 and 2 contain the [Fe4(mu3-O)2]8+ core comprising four Fe(III) ions in a "butterfly" disposition and two mu3-O2- ions, each bridging three Fe(III) ions forming the "wings" of the "butterfly". The Mössbauer spectra of 1b and 2 consist of composite quadrupole-split doublets, with parameters typical for high-spin Fe(III) in octahedral environments. Magnetic susceptibility measurements on 1a revealed antiferromagnetic interactions between the S = 5/2 ferric ions, with best-fit parameters being J(wb) = -40.2 cm(-1) and J(bb) = -59.4 cm(-1) (H = -2SigmaJiJj) for wingtip-body and body-body interactions, respectively, yielding an S = 1 ground state. Both wingtip-body and body-body interactions are well determined.

Journal Article↗
PubMed2006

Butterfly diradical intermediates in photochemical reactions of Fe2(CO)6(mu-S2).

Photolysis of the tetrahedrane Fe2(CO)6(mu-S2) at 450 +/- 35 nm in a Nujol matrix at low temperatures gives an isomer characterized by its nu(CO) infrared frequencies. Comparison of these experimental frequencies with those calculated by density functional theory using the BP86 functional indicates this photoisomer to be the butterfly singlet diradical Fe2(CO)6S2 isomer in which the S-S bond of the tetrahedrane is broken but the Fe-Fe bond is retained. Photolysis at higher energies (420-280 nm) results in CO loss from this singlet butterfly diradical as indicated again by comparison of the experimental infrared nu(CO) frequencies with those calculated for an Fe2(CO)5S2 isomer of this type.

Journal Article↗
PubMed2000

Epoxidation of acyclic chiral allylic alcohols with peroxy acids: spiro or planar butterfly transition structures? A computational DFT answer

The mechanism of the epoxidation of two chiral allylic alcohols, i.e., 3-methyl-3-buten-2-ol and (Z)-3-penten-2-ol, with peroxyformic acid has been investigated by locating 20 transition structures with the B3LYP/6-31G* method and by evaluating their electronic energy also at the B3LYP/6-311+G**@B3LYP/6-31G* theory level. Relative stability of TSs, as far as electronic energy is concerned, is basis set dependent; moreover, it also depends on entropy and solvent effects. Free enthalpies, calculated by using electronic energy at the higher theory level and with inclusion of solvent effects, indicates that syn, exo TSs, where the olefinic OH group hydrogen bonds the peroxy oxygens of the peroxy acid, outweigh syn, endo TSs, where the peroxy acid carbonyl oxygen is involved in hydrogen bonding. In the former TSs the peroxy acid moiety maintains its planar geometry while in the latter ones a strong out-of-plane distortion of peroxy acid is observed. This distortion makes it viable an unprecedented 1,2-H shift, as a possible alternative to the 1,4-H shift, for the peroxy acid hydrogen. In fact, for one syn, endo TS IRC analysis demonstrated that the 1,2-H shift mechanism is actually operative. The geometry of all TSs substantially conforms to a spiro (i.e., with the peroxy acid plane almost perpendicular to the C=C bond axis) butterfly orientation of the reactants while no TS resembles, even loosely, the planar butterfly structure. Theoretical threo/erythro epoxide ratios are in fair accord with experimental data. Calculations indicate that threo epoxides derive mostly from TSs in which the olefinic OH assumes an outside conformation while erythro epoxides originate from TSs with the OH group in an inside position. Computational findings do not support the qualitative TS models recently proposed for these reactions.

Journal Article↗
PubMed2001

Novel chemistry of abdominal defensive glands of nymphalid butterfly Agraulis vanillae.

Abdominal defensive glands of both sexes of the Gulf fritillary butterfly, Agraulis vanillae (Linnaeus) (Nymphalidae:Heliconiinae) emit a pronounced odor when disturbed. We have identified 6-methyl-5-hepten-2-one; oleic, palmitic, and stearic esters of the corresponding alcohol 6-methyl-5-hepten-2-ol; hexadecyl acetate; 1,16-hexadecanediol diacetate; and 1,15-hexade-canediol diacetate in the glandular exudate. Since we have determined that free-flying birds or birds in a butterfly conservatory discriminate against A. vanillae as prey, we suggest that the constituents in the glands may play a defensive role against potential avian predators.

Abdomen↗
PubMed1993

Butterfly-shaped pigment dystrophy of the fovea caused by a point mutation in codon 167 of the RDS gene.

Butterfly-shaped pigment dystrophy of the fovea is an autosomal dominant eye disease characterized by a bilateral accumulation of yellowish or pigmented material at the level of the retinal pigment epithelium. It shares some clinical and histopathologic features with age related macular degeneration which is the most common cause of legal blindness in older patients. We screened affected patients from a three generation family with butterfly dystrophy for mutations in candidate genes. A base substitution was identified in the peripherin (RDS) gene and DNA sequencing revealed a G to A transition in codon 167 that substitutes aspartic acid for a highly conserved glycine. The mutation segregates with the disease phenotype (Zmax = 4, theta = 0) strongly suggesting that it causes the macular disease in this family.

Adult↗
PubMed2002

Wolbachia infection associated with all-female broods in Hypolimnas bolina (Lepidoptera: Nymphalidae): evidence for horizontal transmission of a butterfly male killer.

Inherited bacteria that kill male hosts during embryogenesis infect a wide range of insect species. In order to ascertain if there are patterns to host infection, with particular male killing bacteria specialising on particular taxa, we investigated the male killing trait in the butterfly Hypolimnas bolina. All-female broods were first reported in this species in the 1920s. Investigation of this system in the Fiji Islands revealed the causal agent of sex ratio distortion in H. bolina to be a male killing Wolbachia bacterium. This bacterium is identical in wsp and ftsZ sequence to a male killer in the butterfly Acraea encedon in Tanzania, suggesting it has moved between host species, yet retained its phenotype. The prevalence of the Wolbachia was calculated for three different island groups of Fiji, and found to vary significantly across the country. Antibiotics failed to cure either the male killing trait or the Wolbachia infection. The implications of these results are discussed.

Animals↗
PubMed1999

Influence of landscape on the population genetic structure of the alpine butterfly parnassius smintheus (Papilionidae)

Four microsatellite DNA markers were developed which were used to examine the relationship between landscape and population genetic structure among a set of populations of the butterfly Parnassius smintheus located in the foothills of the Canadian Rockies. Detailed information on the dispersal of adult butterflies among this same set of populations was available. Simple and partial Mantel tests were used to examine the relationships between genetic distances, predicted rates of dispersal, and a number of landscape variables, all measured pairwise for 17 sample sites. Nei's standard genetic distance was negatively correlated with predicted dispersal. We observed a significant pattern of isolation by distance at a very small spatial scale. The distance between sites that was through forest was a stronger predictor of genetic distance than the distance through open meadow, indicating a significant effect of landscape on population genetic structure beyond that of simple isolation by distance. Our results suggest that rises in the tree-line in alpine areas, caused by global warming, will lead to reduced gene flow among populations of P. smintheus.

Journal Article↗
PubMed2006

Arm to leg coordination in elite butterfly swimmers.

This study proposed the use of four time gaps to assess arm-to-leg coordination in the butterfly stroke at increasing race paces. Fourteen elite male swimmers swam at four velocities corresponding to the appropriate paces for, respectively, the 400-m, 200-m, 100-m, and 50-m events. The different stroke phases of the arm and leg were identified by video analysis and then used to calculate four time gaps (T1: time gap between entry of the hands in the water and the high break-even point of the first undulation; T2: time gap between the beginning of the hands' backward movement and the low break-even point of the first undulation; T3: time gap between the hands' arrival in a vertical plane to the shoulders and the high break-even point of the second undulation; T4: time gap between the hands' release from the water and the low break-even point of the second undulation), the values of which described the changing relationship of arm to leg movements over an entire stroke cycle. With increases in pace, elite swimmers increased the stroke rate, the relative duration of the arm pull, the recovery and the first downward movement of the legs, and decreased the stroke length, the relative duration of the arm catch phase and the body glide with arms forward (measured by T2), until continuity in the propulsive actions was achieved. Whatever the paces, the T1, T3, and T4 values were close to zero and revealed a high degree of synchronisation at key motor points of the arm and leg actions. This new method to assess butterfly coordination could facilitate learning and coaching by situating the place of the leg undulation in relation with the arm stroke.

Acceleration↗
PubMed2000

Inlay butterfly cartilage tympanoplasty (Eavey technique) modified for adults.

INTRODUCTION: Popular myringoplasty techniques include either an underlay or an onlay approach using tissues such as temporalis fascia or perichondrium as grafts. In 1998, Eavey described an inlay tympanoplasty technique in children using a cartilage graft which resembled butterfly wings. This technique was effective for closure of tympanic membrane perforations, while being more rapid for the surgeon and more comfortable for the patient. The aim of this study was to describe our results with modification of this technique in adults under local anesthesia. METHODS AND MATERIAL: Cartilage butterfly inlay tympanoplasty was carried out in 20 adult patients to close small-to-medium tympanic membrane perforations over a period of 11 months. Compared with the original description, 3 modifications are noted: (1) adult patients, (2) local anesthesia, and (3) no skin graft over the cartilage. We evaluated the success rate and postoperative hearing results. RESULTS: Two patients were not evaluated in terms of hearing gain because they had profound preoperative hearing loss. Fourteen patients had a postoperative 4 pure-tone average between 0 and 9 dB, 3 patients between 10 and 20 dB, and 1 patient greater than 20 dB. The graft "take rate" was 90% (18/20) at the end of the follow-up period (mean follow-up 7.25 months). Seventeen of 18 successful cases had cartilage grafts that were intact and dry at the last visit. CONCLUSIONS: The tympanoplasty technique described by Eavey is effective to close tympanic membrane perforation in adults as well as children. The technique modifications introduced here (abandonment of the skin graft and local anesthesia) reduced surgery time and postoperative morbidity. Postoperative results compared with those of the original technique were good.

Adolescent↗
PubMed2003

The power of evo-devo to explore evolutionary constraints: experiments with butterfly eyespots.

Examples of adaptive radiation by Darwinian evolution will always enthral, and the theory of natural selection binds the whole of biology. But is selection all-powerful? Evolutionary developmental biology is beginning to provide the background to understanding how the internal organisation of organisms can influence the tempo and direction of evolutionary change. Do the mechanisms that generate the phenotype channel, bias or limit morphological evolution? The formation of eyespots on the wings of the butterfly Bicyclus anynana is a process which is becoming comparatively well understood from the genetical, developmental and ecological perspectives. We have begun to combine this knowledge with artificial selection experiments to examine the rates at which morphological changes of a particular eyespot pattern in different directions can be achieved. Our initial selection experiment performed over twenty-five generations has shown that in contrast to predictions based on shared genetical and developmental properties, two butterfly eyespots on the same wing surface can be freely uncoupled from each other with respect to their pattern of relative sizes. This flexibility in development and in response to selection may occur because our base population is part of a lineage with a long legacy of natural selection building up genetic variation that enables independent behaviour for eyespot size, and thus it no longer reflects a tightly modular organisation of eyespots as may well have existed close to their evolutionary origin in basal Lepidoptera. Comparisons can be made between such descriptions of the potential for short-term changes in morphology in B. anynana and observed patterns of divergence among all extant species in this species-rich genus. Being able to map phenotypes onto genotypes via developmental processes provides a powerful basis for exploring genetical and developmental constraints. This will eventually lead to examples of evolutionary constraints that represent more than 'just-so' stories, and thus to a more balanced view of Darwinian evolution.

Journal Article↗
PubMed1991

The butterfly rash and the malar flush. What diseases do these signs reflect?

The butterfly rash and malar flush are common facial manifestations of several disorders. Systemic lupus erythematosus may produce a transient rash before any other signs. In pellagra, symmetric keratotic areas on the face are always accompanied by lesions elsewhere on the body. Erysipelas produces brawny, fiery red facial lesions, and scarlet fever causes facial eruptions as part of a generalized eruption. Lupus vulgaris and lupus pernio produce nodules that may spread in a butterfly pattern, and seborrheic dermatitis has a predilection for the malar prominences and other areas of the face. Carcinoid syndrome often causes flushing attacks that vary in duration, and facial flushing that lasts throughout treatment may accompany chemotherapy if the patient has a hypersensitivity reaction. Deep-red rashes and/or lichenoid lesions may be caused by graft-versus-host disease in a patient undergoing bone marrow transplantation.

Dermatitis, Seborrheic↗
PubMed2002

Kinematic analysis of butterfly turns of international and national swimmers.

The aims of this study were (1) to evaluate the different turn phases of 200 m butterfly during competition in a 50 m pool, (2) to determine if wall contact times are related to swim speed and (3) to compare the turn variables of a European Champion with other swimmers. In the first part of the study, we assessed the turns of 22 swimmers ranked in three groups according to 200 m butterfly swim performance (fast group = 121.73+/-3.03 s, intermediate group = 126.25+/-0.55 s, slow group = 129.24+/-2.30 s). Two turn times were recorded: the first before the turn (i.e. the time it takes the swimmer's head to reach the wall from 7.5 m away) and the second after the turn (i.e. the time from the wall to the point at which the swimmer's head passes 7.5 m away). The third turn was performed significantly faster by the fast group than by the slow group, both before (P< 0.01) and after (P< 0.02) the turn. In the second part of the study, objectives (2) and (3) were evaluated among 15 swimmers based on a specific protocol. Three cameras (50 Hz) simultaneously recorded the turn; these were placed above the water 10 m before the wall, 5 m before and just above the wall. Longer contact times of the feet on the wall were associated with a faster push-off speed (P < 0. 02). The European Champion achieved an improved contact time while performing a rapid pull-out speed.

Analysis of Variance↗
PubMed2000

The Dispersal System of a Butterfly: A Test of Source-Sink Theory Suggests the Intermediate-Scale Hypothesis.

Theory predicts source-sink dynamics can occur in species with the ideal preemptive distribution but not with the ideal free distribution. Source-sink dynamics can also occur in species with passive dispersal, in which a fixed fraction of the population disperses each generation. However, in nature, dispersal often approximates random diffusion rather than ideal choices or fixed probabilities. Here, I ask which dispersal system occurred in a butterfly (Euphydryas editha) known to have source-sink dynamics. The study used 13 experimental sites, where vacant and occupied habitat patches were juxtaposed. I estimated movement during the flight season and tested hypotheses about the type of dispersal system. Ideal free and ideal preemptive models were rejected because per capita movement rates were density independent. Passive dispersal was rejected because per capita rates were related to patch area and habitat preference. The diffusion model best explained the data because it predicted both the area relationship and an odd feature of the habitat preference: immigration was not higher in preferred habitat; rather, emigration was lower. The diffusion model implied that source-sink dynamics were driven by diffusion from areas of high to low population density. Existing source-sink theory assumes fine-scale patchiness, in which animals have perfect knowledge and ease of mobility. The results from the butterfly suggest that source-sink dynamics arise at coarser spatial scales, where diffusion models apply.

diffusion↗
PubMed2002

The 'butterfly' graft in functional secondary rhinoplasty.

OBJECTIVE: To describe a surgical technique (the conchal cartilage "butterfly" graft) which, when used in properly selected patients, has been found to be a dependable method for alleviation of postrhinoplasty internal nasal valve dysfunction. STUDY DESIGN: Retrospective chart review. METHODS: Analysis of consecutive patients with weakness and/or collapse of the upper lateral cartilages following rhinoplasty. Seventy-two patients (37 women and 35 men, age range 17-76 y) had severe nasal obstruction and were found to have indications for this procedure. All patients had undergone at least one rhinoplastic procedure. All patients were followed for a minimum of 2 years after surgery. RESULTS: All 72 patients experienced significant subjective improvement in relative nasal obstruction. Two patients (3%) reported less than total resolution of their difficulty breathing through their nose; the remaining 70 patients (97%) reported complete resolution of their nasal airway problems. No patients reported their postoperative nasal obstruction as the same or worse than their preoperative baseline. Sixty-two patients (86%) reported improvement in the appearance of their nose, 8 patients (11%) felt that their appearance was unchanged, and 2 patients (3%) felt that the appearance of their nose was made worse by the procedure. CONCLUSIONS: Patients presenting with nasal obstruction after rhinoplasty are frequently found to have collapse and/or weakening of their upper lateral cartilages with resulting nasal valve dysfunction. The conchal cartilage "butterfly" graft is a technique which, when properly performed during revision rhinoplasty, yields predictable functional and cosmetic results with minimal morbidity.

Adolescent↗
PubMed2001

Hofstadter butterfly and integer quantum hall effect in three dimensions.

For a three-dimensional (3D) lattice in magnetic fields we have shown that the hopping along the third direction, which normally smears out the Landau quantization gaps, can rather give rise to a Hofstadter's butterfly specific to 3D when a criterion is fulfilled by anisotropic (quasi-one-dimensional) systems. In 3D the angle of the magnetic field plays the role of the field intensity in 2D, so that the butterfly can occur in much smaller fields. We have also calculated the Hall conductivity in terms of the topological invariant in the Kohmoto-Halperin-Wu formula, and each of sigma(xy),sigma(zx) is found to be quantized.

Journal Article↗
PubMed2004

Detection of a Landau band-coupling-induced rearrangement of the Hofstadter butterfly.

The spectrum of 2D electrons subjected to a weak 2D potential and a perpendicular magnetic field is composed of Landau bands with a fractal internal pattern of subbands and minigaps referred to as Hofstadter's butterfly. The Hall conductance may serve as a spectroscopic tool as each filled subband contributes a specific quantized value. Advances in sample fabrication now finally offer access to the regime away from the limiting case of a very weak potential. Complex behavior of the Hall conductance is observed and assigned to Landau band-coupling-induced rearrangements within the butterfly.

Journal Article↗
PubMed1993

Intracutaneous butterfly suture with absorbable synthetic suture material. Technique, tissue reactions, and results.

BACKGROUND: Tension on surgical wound edges is often an obstacle to proper closure and good cosmetic results in dermatologic surgery. OBJECTIVE: A buried, butterfly-shaped, interrupted suture has been developed to remedy this. The suture is anchored very broadly in the corium, the knot is below the corium. The butterfly suture can be supplemented by a temporary running suture or by close-set, superficially placed interrupted sutures. METHODS: This technique was studied in a follow-up of 876 operations, with histologic study of 60 scars resulting from the suture. In particular, the specific advantages and disadvantages of two synthetic suture materials were compared: monofilament (polydioxanon) and polyfilament (polyglactin 910). RESULTS: Polydioxanon sutures were found to be clinically superior. It was important, however, that the suture knot be deeply anchored and that the surgeon be experienced. CONCLUSION: Cosmetic results of 18,000 procedures with this suture over a period of 6 years were found to be clearly better than those of surgery with conventional sutures.

Absorption↗
PubMed2006

Influence of swimsuit design and fabric surface properties on the butterfly kinematics.

This study investigated the influence of the covering swimsuit and the fabric surface properties on the butterfly stroke kinematics. Surface properties were evaluated by wetting measurements of two fabric samples: one for training suits and one for competition suits. The surface of the second one was coated by mechanochemical treatment in order to modify its surface properties. Nine national level swimmers performed a 50-m butterfly at submaximal velocity in three swimsuit conditions: conventional, long, and coated long swimsuits. From video recording, the hip was digitized at the entry and exit of the swimmer's hand in order to calculate the duration, hip displacement, and hip linear velocity during underwater and recovery phases and during stroke. The results for wetting show that competition fabric was more water-repellent than training fabric, but both were isotropic. Moreover, the mechanochemical treatment increased water repellency and anisotropy. The swimming results indicated that, when compared to a conventional swimsuit, wearing a coated long swimsuit increased hip linear velocity during stroke, and particularly during the recovery phase which had a shorter duration. These results suggest that the covering swimsuit should be coupled with the water repellent and anisotropic properties of the fabric surface in order to improve swimming performance.

Biomechanical Phenomena↗