The importance of loop length on the stability of i-motif structures

Using UV and srCD spectroscopy it is found that loop length within the i-motif structure is important for both thermal and pH stability, but in contrast to previous statements, it is the shorter loops that exhibit the highest stability.

Assessment of variations of the mandibular canal through cone beam computed tomography

The neurovascular bundle may be vulnerable during surgical procedures involving the mandible, especially when anatomical variations are present. Increased demand of implant surgeries, wider availability of three-dimensional exams, and lack of clear definitions in the literature indicate that features of anatomical variations should be revisited. The objective of the study was to evaluate features of anatomical variations related to mandibular canal (MC), such as bifid canals, anterior loop of mental nerve, and corticalization of MC. Additionally, bone trabeculation at the submandibular gland fossa region (SGF) was assessed and related to visibility of MC. Cone beam computed tomography exams from 100 patients (200 hemimandibles) were analyzed and the following parameters were registered: diameter and corticalization of MC; trabeculation in SGF region; presence of bifid MC, position of bifurcations, diameter, and direction of bifid canals; and measurement of anterior loops by two methods. Corticalization of the MC was observed in 59% of hemimandibles. In 23%, MC could be identified despite absence of corticalization. Diameter of MC was between 2.1 and 4 mm for nearly three quarters of the sample. In 80% of the sample trabeculation at the SGF was either decreased or not visible, and such cases showed correlation with absence of MC corticalization. Bifid MC affected 19% of the patients, mostly associated with additional mental foramina. Clinically significant anterior loop (> 2 mm of anterior extension) was observed in 22-28%, depending on the method. Our findings, together with previously reported limitations of conventional exams, draw attention to the unpredictability related to anatomical variations in neurovascularization, showing the contribution of individual assessment through different views of three-dimensional imaging prior to surgical procedures in the mandible.

Location and dimensions of the mental foramen: a radiographic analysis by using cone-beam computed tomography

INTRODUCTION The mental foramen (MF) is an important landmark in dentistry. Knowledge of its position is central to perform block anesthesia of the mental nerve or to avoid nerve damage during surgical procedures in the premolar area of the mandible. The present radiographic study aimed at evaluating the location and dimension of the MF and measuring distances to neighboring structures by using limited cone-beam computed tomography (CBCT). METHODS Sagittal, axial, and coronal CBCT images of 142 patients (26 bilateral and 116 unilateral cases) were retrospectively screened to determine the location of the MF with respect to adjacent teeth and to take linear measurements of the size of the MF and its distances to the upper and lower borders of the mandible. In addition, the course and angulation of the mental canal exiting the MF were assessed. RESULTS The majority of MF (56%) were located apically between the 2 premolars, and another 35.7% of MF were positioned below the second premolar. On average, the MF was localized 5.0 mm from the closest root of the adjacent tooth (range, 0.3-9.8 mm). The mean size of the MF showed a height of 3.0 mm and a length of 3.2 mm; however, individual cases showed large differences in height (1.8-5.1 mm) and in length (1.8-5.5 mm). All mental canals exiting the MF demonstrated an upward course in the coronal plane, with 70.1% of the mental canal presenting an anterior loop (AL) in the axial view. The mean extension of AL in cases with an AL was 2.3 mm. CONCLUSIONS This study is consistent with previous radiographic studies regarding size and location of MF and distances between MF and adjacent anatomic structures. The assessed bilateral cases showed a high intraindividual concordance for certain features when comparing right and left sides.

Modeling 2R regenerator based on High Nonlinear Dispersion Imbalanced Loop Mirror (HN-DILM)

The model of Reshaping and Re-amplification (2R) regenerator based on High Nonlinear Dispersion Imbalanced Loop Mirror (HN-DILM) has been designed to examine its capability to reduce the necessary of fiber loop length and input peak power by deploying High Non linear Fiber (HNLF) compared to Dispersion Shifted Fiber (DSF). The simulation results show by deployed a HNLF as a nonlinear element in Dispersion Imbalanced Loop Mirror (DILM) requires only 400mW peak powers to obtain a peak of transmission compared to DSF which requires a higher peak power at 2000mW to obtain a certain transmissivity. It also shows that HNLF required shorter fiber length to achieve the highest transmission. The 2R regenerator also increases the extinction ratio (ER) of the entire system. © 2010 IEEE.

Desenvolvimento de estruturas fibrosas com comportamento auxético

Tese de Doutoramento Engenharia Têxtil

Helminth parasites of fishes from the hydroeletric power station of eletrosul (Brazil). I: Procamallanus petterae n. sp. and Spirocamallanus pintoi n. sp. (Nematoda, Camallanidae) from the reservoir of Salto Osório

Procamallanus petterae n. sp. from Plecostomus albopunctarus and Spirocamallanus pintoi n. sp. from Corydoras paleatus are described. procamallanus petterae n. sp. differs from all other species of the genus by having a buccal capsule without spiral bands, with five teeth-like structures on its base and four plate-like structures near the anterior margin; length ratio of oesophagus muscular/glandular 1:1.4; spicules short, 21µ m and 16µ m long and tails ending abruptly in a sharp point, in both sexes. Spirocamallanus pintoi n. sp. is characterized by having 6 to 8 spiral thickenings in the buccal capsule of male and 9 to 10 in female, occupying 2/3 of the length of the capsule; length of glandular oesophagus more than twice the muscular; spicules short, the right 94µ m and the left 82µ m long.

Simulations numériques de la dynamique des protéines : translation de ligands, flexibilité et dynamique des boucles

La flexibilité est une caractéristique intrinsèque des protéines qui doivent, dès le mo- ment de leur synthèse, passer d’un état de chaîne linéaire à un état de structure tridimen- sionnelle repliée et enzymatiquement active. Certaines protéines restent flexibles une fois repliées et subissent des changements de conformation de grande amplitude lors de leur cycle enzymatique. D’autres contiennent des segments si flexibles que leur structure ne peut être résolue par des méthodes expérimentales. Dans cette thèse, nous présentons notre application de méthodes in silico d’analyse de la flexibilité des protéines : • À l’aide des méthodes de dynamique moléculaire dirigée et d’échantillonnage pa- rapluie, nous avons caractérisé les trajectoires de liaison de l’inhibiteur Z-pro- prolinal à la protéine Prolyl oligopeptidase et identifié la trajectoire la plus pro- bable. Nos simulations ont aussi identifié un mode probable de recrutement des ligands utilisant une boucle flexible de 19 acides aminés à l’interface des deux domaines de la protéine. • En utilisant les méthodes de dynamique moléculaire traditionnelle et dirigée, nous avons examiné la stabilité de la protéine SAV1866 dans sa forme fermée insérée dans une membrane lipidique et étudié un des modes d’ouverture possibles par la séparation de ses domaines liant le nucléotide. • Nous avons adapté auproblème de la prédiction de la structure des longues boucles flexibles la méthode d’activation et de relaxation ART-nouveau précédemment uti- lisée dans l’étude du repliement et de l’agrégation de protéines. Appliqué au replie- ment de boucles de 8 à 20 acides aminés, la méthode démontre une dépendance quadratique du temps d’exécution sur la longueur des boucles, rendant possible l’étude de boucles encore plus longues.

Estudos sobre estrutura, ciclo de vida e comportamento de Sardinella brasiliensis (Steindachner, 1879) na área entre 22ºS e 28ºS, Brasil: 4. Crescimento: aspectos quantitativos

Foram estimados os parâmetros de crescimento em comprimento e peso para Sardinella brasiliensisda costa sudeste do Brasil (22ºS-28ºS), evidenciando-se dois padrões de crescimento distintos: um, para os exemplares que ocupam as regiões estuarino-lagunares de Cananeia e Paranaguá (25º-26ºS; III) e outro, para aqueles que ocupam as regiões costeiras da plataforma. Nestas regiões foi identificado um grupo no extremo norte da região (22º- 23ºS; I) com crescimento mais intenso que o verificado para o resto da área (23º-25ºS; II e 26º- 28ºS; IV). Os resultados sugerem que a espécie não é homogênea na região, reforçando hipótese anterior.

[The mental foramen or "the crossroads of the mandible." An anatomic and clinical observation]

This paper presents a clinical and anatomical review of the mental foramen (MF) based on recent publications (since 1990). Usually, the MF is located below the 2nd premolar or between the two premolars, but it may also be positioned below the 1st premolar or below the mesial root of the 1st molar. At the level of the MF, lingual canals may join the mandibular canal (hence the term "crossroads"). Accessory MF are frequently described in the literature with large ethnic variations in incidence. The emergence pattern of the mental canal usually has an upward and posterior direction. The presence and extent of an "anterior loop" of the mental canal may be overestimated with panoramic radiography. Limited cone-beam computed tomography currently appears to be the most precise radiographic technique for assessment of the "anterior loop". The mental nerve exiting the MF usually has three to four branches for innervation of the soft tissues of the chin, lower lip, facial gingiva and mucosa in the anterior mandible. The clinician is advised to observe a safety distance when performing incisions and osteotomies in the vicinity of the MF.

A modified gambler's ruin model of polyethylene chains in the amorphous region.

Polyethylene chains in the amorphous region between two crystalline lamellae M unit apart are modeled as random walks with one-step memory on a cubic lattice between two absorbing boundaries. These walks avoid the two preceding steps, though they are not true self-avoiding walks. Systems of difference equations are introduced to calculate the statistics of the restricted random walks. They yield that the fraction of loops is (2M - 2)/(2M + 1), the fraction of ties 3/(2M + 1), the average length of loops 2M - 0.5, the average length of ties 2/3M2 + 2/3M - 4/3, the average length of walks equals 3M - 3, the variance of the loop length 16/15M3 + O(M2), the variance of the tie length 28/45M4 + O(M3), and the variance of the walk length 2M3 + O(M2).

Curvature versus V-bends in a group B titanium T-loop spring

Objective: To compare the system of forces acting on curvature and preactivated V-bends in titanium T-loop springs (TTLSs) made of 0.017- X 0.025-inch TMA (titanium molibdenium alloy) wire.Materials and Methods: Pictures of TTLSs preactivated by curvature and V-bends were inserted in the LOOP software program to design both TTLSs. Symmetry was assured using the program. Both TTLSs used the same amount (length) of wire and had the same angulation between their anterior and posterior extremities when passive. The loops were activated 7 mm, and forces and moments were registered after each 0.5 mm of deactivation. The brackets were at the same height, separated by 23 mm and angulated 0 degrees.Results: The preactivated curvature TTLS delivered horizontal forces ranging from 34 gF to 456 gF, while the TTLS preactivated by V-bends delivered forces ranging from 54 gF to 517 gF. The forces decreased more (30 gF vs 33 gF) with every 0.5 mm of activation on the preactivated V-bend TTLS than on the preactivated curvature TTLS. Vertical forces were low and clinically insignificant for both TTLSs. The moment to force (MF) ratios were systematically higher on the preactivated curvature than on the preactivated V-bend TTLS (from 5.8 mm to 38.8 mm vs 4.7 mm to 28.3 mm).Conclusions: Although both loops show symmetrical moments in their anterior and posterior extremities and can be used for group B anchorage, the curvature preactivated TTLS delivers lower horizontal forces and higher MF ratios than the acute preactivated V-bend TTLS.