Molecular dynamics study on atomic elastic stiffness at mode I crack along bi-metal interface.

Propagation of mode I crack along bi-metal (001) interfaces of Fe/W, Fe/Ni, Fe/Co and Ti/Mg is simulated by molecular dynamics and discussed with the eigenvalue/vector of the atomic elastic stiffness, [Formula: see text], and surface energy. The crack does not propagate at the interface but in the adjacent phase of smaller surface energy, except in Fe/Ni. The 1st eigenvalue ηa(1), or the solution of [Formula: see text] of each atom, clarifies the difference of 'soft/hard' of both phases at the onset of crack propagation. In the case of Fe/Ni, the ηa(1) of Ni atoms remarkably decreases in the Fe/Ni bi-metal structure, even though Ni has higher ηa(1) than Fe at no-load perfect lattices. Thus the rupture occurs in the Ni side even though the Ni has slightly higher (001) surface energy than Fe. Deformation modes at the crack propagation are also visualized by the eigenvector of ηa(1) < 0 unstable atoms. This article is part of the theme issue 'Fracture dynamics of solid materials: from particles to the globe'.

Influence of balancing-side occlusal interference on smoothness of working-side condylar movement and intra-articular space in chewing efforts.

Response of temporomandibular joint (TMJ) articulation adapting to occlusal alteration has been sparsely known. For 10 healthy adults with acceptably good occlusion, an artificial occlusal interference (OI) was introduced to the lower molar on the balancing side of unilateral chewing. Subjects were asked to chew a gum on their preferred side. The chewing jaw movements with/without the OI were recorded using a video-based optoelectronic system. The mandibular movements were generated in each individual's TMJ model reconstructed by magnetic resonance images. The smoothness of local condylar point movements towards the normal direction of the condylar surface and interarticular space on the working side was measured. Overall, the smoothness of condylar point movements in the closing phase was impaired immediately after introduction of the OI. In the intercuspal phase, the OI increased the joint space. After about 60 chewing cycles, the movement smoothness and joint space began to recover. These findings suggest that OI on the balancing side induced irregular stress field translation on the working-side condylar surface followed by acute recovery process.

Temporomandibular joint articulations on working side during chewing in adult females with cross-bite and mandibular asymmetry.

Influence of mandibular asymmetry and cross-bite on temporomandibular joint (TMJ) articulation remained unknown. This study aimed to investigate whether/how the working-side condylar movement irregularity and articular spaces during chewing differ between patients with mandibular asymmetry/cross-bite and control subjects. The cross-bite group and the control group consisted of 10 adult female patients and 10 adult female subjects, respectively. They performed unilateral gum-chewing. The mandibular movements were recorded using a video-based opto-electronic system. The 3D articular surface of the TMJ for each individual was reconstructed using CT/MRI data. For local condylar points, the normalised jerk cost (NJC) towards normal direction to the condylar surface, the angle between tangential velocity vector and condylar long axis and intra-articular space were measured. Three rotatory angles at centre of the condyle were also measured. During closing and intercuspation, (i) movements of posterior portion of the deviated side condyle showed significantly less smoothness as compared with those for the non-deviated side and control subjects, (ii) the rotations of the condyle on the deviated side induced greater intra-articular space at posterior and lateral portions. These findings suggest that chewing on the side of mandibular deviation/cross-bite may cause irregular movement and enlarged intra-articular space at posterior portion of the deviated side condyle.

Improvements in smoothness of chewing cycles in adults with mandibular prognathism after surgery: a longitudinal study.

Although adults with mandibular prognathism are known to show impaired smoothness of masticatory jaw movements, it remains uncertain whether/how the surgical-orthodontic treatment is effective to improve masticatory jaw movements. The aims of this study were (i) to verify whether the surgical-orthodontic treatment of patients with mandibular prognathism improve smoothness of the chewing jaw movements post-operatively and, if so, (ii) to examine whether the improved parameters show similar quantities as those of the control subjects. The chewing jaw movements for 13 patients with mandibular prognathism were recorded at pre- and post-treatment stages. The patient group was divided into two groups: Class III(closed) showed full occlusal contact at the habitual intercuspal position, whereas Class III(open) showed inability of occlusal contact between the upper and lower anterior teeth. The control group (CG) consisted of 52 subjects having acceptably good occlusion. The normalised jerk cost (NJC), movement duration and peak velocity in jaw closing were compared. For both Class III(open) and Class III(closed) groups, statistical comparisons revealed that the NJC and movement duration were decreased after the treatment, whereas the peak velocity was increased (all P < 0·01). For the Class III(open), these quantities at the post-treatment stage did not show any significant differences compared with those for the CG. It is concluded that the smoothness of chewing jaw movements for patient with mandibular prognathism were improved after treatment, and for the patients with anterior open bite at pre-treatment, the post-operatively achieved smoothness of jaw-closing movements did not differ from those of the CG.

Smoothness of chewing jaw movements in adults with mandibular prognathism.

Indices such as smoothness, movement time, peak velocity, and symmetry of the velocity profile have been shown to be effective in explaining the degree of skilfulness of human saccadic eye, limb, and jaw motions. We investigated whether adult subjects with mandibular prognathism show impaired smoothness of the masticatory jaw movements. Forty-nine adults with skeletal Class III malocclusions and 52 healthy adults with acceptably good occlusions were selected respectively as Test and Control subjects. Subjects of the Test Group were subdivided into two groups: Class III(closed) showed full occlusal contact between the upper and lower teeth at the habitual intercuspal position, whereas Class III(open) showed inability of occlusal contact between the upper and lower anterior teeth. Each subject was asked to chew a piece of chewing gum. The normalised jerk-cost (NJC), movement duration, and tangential velocity profile during jaw-closing movements were compared between groups. Test Groups showed greater NJC (P < 0·01) with longer movement duration (P < 0·01) and lower peak velocity (P < 0·01) than the Control Group did. Class III(closed) showed greater NJC (P < 0·01) with longer movement duration (P < 0·01) and lower peak velocity (P < 0·01) than Class III(open) did. Results show that the mandibular movements made by the Test Groups exhibit lower skilfulness than those made by the Control Group. The jaw movement skilfulness of the prognathic patients decreases most drastically with existence of malocclusal contact between upper and lower anterior teeth.

Masticatory jaw movement optimization after introduction of occlusal interference.

How 'control' characteristics of masticatory jaw movement, such as skilfulness of the movement, change after alteration in occlusion remains uncertain. For each of 10 healthy adults with good occlusion, an occlusal interference with artificial 'tooth-cusp' was introduced to the crown of the upper molar tooth on the non-working side of unilateral chewing. Mandibular incisor-point movements were then recorded by a 3D tracking device. The introduction of the occlusal interference induced a remarkable increase in the normalized jerk-cost (NJC), prolonged duration of the decelerative phase and lowered peak velocity for jaw closing movement during chewing. Overall, the NJC and velocity profile showed significant recoveries during the course of about 90 repetitive chewing cycles performed under the altered occlusal condition. These findings suggest that acute adaptive changes of jaw motion after introduction of occlusal interference might be characterized as the recovery process of movement skilfulness in terms of movement smoothness and velocity profile.

Low-volume muscle endurance training prevents decrease in muscle oxidative and endurance function during 21-day forearm immobilization.

AIM: To examine the effects of low-volume muscle endurance training on muscle oxidative capacity, endurance and strength of the forearm muscle during 21-day forearm immobilization (IMM-21d). METHODS: The non-dominant arm (n = 15) was immobilized for 21 days with a cast and assigned to an immobilization-only group (Imm-group; n = 7) or an immobilization with training group (Imm+Tr-group; n = 8). Training comprised dynamic handgrip exercise at 30% of pre-intervention maximal voluntary contraction (MVC) at 1 Hz until exhaustion, twice a week during the immobilization period. The duration of each exercise session was 51.7 +/- 3.4 s (mean +/- SE). Muscle oxidative capacity was evaluated by the time constant for phosphocreatine recovery (tau(off)PCr) after a submaximal handgrip exercise using (31)phosphorus-magnetic resonance spectroscopy. An endurance test was performed at 30% of pre-intervention MVC, at 1 Hz, until exhaustion. RESULTS: tau(off)PCr was significantly prolonged in the Imm-group after 21 days (42.0 +/- 2.8 and 64.2 +/- 5.1 s, pre- and post-intervention respectively; P < 0.01) but did not change for the Imm+Tr-group (50.3 +/- 3.0 and 48.8 +/- 5.0 s, ns). Endurance decreased significantly for the Imm-group (55.1 +/- 5.1 and 44.7 +/- 4.6 s, P < 0.05) but did not change for the Imm+Tr-group (47.9 +/- 3.0 and 51.7 +/- 4.0 s, ns). MVC decreased similarly in both groups (P < 0.01). CONCLUSIONS: Twice-weekly muscle endurance training sessions, each lasting approx. 50 s, effectively prevented a decrease in muscle oxidative capacity and endurance; however, there was no effect on MVC decline with IMM-21d.

Influence of gum-chewing on the haemodynamics in female masseter muscle.

Blood flow in active skeletal muscles provides energy substrate, oxygen and reduction of excessive heat and metabolic by-products. Although cyclic jaw motions such as those during mastication and speech articulation are the primitive oro-facial functions, possible effects of the cyclic muscle contractions on the intramuscular haemodynamics of the jaw muscles remains scarcely known. We investigated the masseteric haemodynamics during and after gum-chewing. Ten healthy female adults participated in the study. Electromyography, kinetics of masseter muscle oxygenation, electrocardiogram and blood pressure were recorded simultaneously. The subjects were asked to perform gum-chewing and cyclic jaw motion without gum bolus (empty-chewing task). The haemodynamics parameters were compared between the two experimental conditions. During gum-chewing task, deoxygenated haemoglobin and sympathetic nerve activity increased, while tissue blood oxygen saturation decreased. Blood pressure and parasympathetic nerve activity did not change. The overall behaviour of haemodynamic parameters during empty-chewing task was similar to that observed during gum-chewing task. However, the latency periods from the end of chewing until significant changes in the haemodynamic parameters were notably shorter (P < 0.05) in gum-chewing task as compared with those associated with empty-chewing task. The duration of the changes was shorter with empty-chewing than with gum-chewing. Fluctuations in masseter muscle haemodynamics associated with chewing jaw movement differed depending on the level of muscle contraction during movement. The differences became statistically significant immediately after the commencement of chewing and after the cessation movement. During the chewing movement, automatic nerve activities increased in response to the level of muscle contraction during movement.

[Primary arterial switch operation for complete transposition of the great arteries (type I) of a neonate weighing 1,378 g].

A 2-day-old female baby, delivered by emergent cesarean section at 35 weeks of gestational age with a birth weight of 1,378 g, was referred to our institute for intensive care of heart failure. By echocardiography and cardiac catheterization, the patient was diagnosed with isolated complete transposition of the great arteries. Primary arterial switch operation was performed at 13 days of age. No technical difficulty arose, imposed by the small size of cardiovascular structure. On the 5th postoperative day, surgical repair of intestinal perforation was performed. Convalescence thereafter was uneventful. She returned home on the 64th postoperative day with the body weight of 2,310 g. We conclude that primary arterial switch operation can be a feasible surgical option even in a neonate with very low birth weight.

The influence of single molar crown placement on the smoothness of masticatory movement.

The jerk-cost is an index that can quantify the smoothness of various movements including human body movements. A previous study reported the usefulness of jerk-cost in the evaluation of masticatory movement, and proposed that the masticatory movement of subjects with good occlusion could be explained as a maximum smooth movement. The purpose of this study was to investigate the influence of a single prosthetic molar restoration on the smoothness of masticatory movement. Fourteen adults who visited this hospital seeking a single prosthetic restoration on a molar were selected. Each subject chewed a piece of chewing gum on the molars of the treated side before and after crown placement. Movement trajectory was recorded using the Sirognathograph Analyzing System. Normalized jerk-cost (NJC) was calculated on the closing phase of each chewing cycle and was compared before and after the crown placement. After the prosthetic restoration, NJC significantly decreased (P < 0.05) in seven subjects with a crown placed on a lower molar, whereas significant changes were not observed in seven subjects with a crown placed on an upper molar. These results suggest that restoring a crown on a lower molar could significantly improve the smoothness of masticatory movement on the same side.

Powdery mildew (Podosphaera xanthii) resistance in melon is categorized into two types based on inhibition of the infection processes.

Physiological races of powdery mildew (Podosphaera xanthii) cause different symptoms in eight melon lines. Infection by races 1, 2, and 5 was examined in different melon lines. After a compatible reaction, conidia germination, haustorium initiation from the germ tube, germ tube branching, and sporulation occurred within 12, 24, 48, and 120 h, respectively, and the conidia matured within 240 h. In contrast, type i and ii inhibition were identified through incompatible reactions. The germ tube and haustorium were initiated from conidia, but no germ tube branching occurred in the lines with type i resistance within 48-240 h. In type ii resistance, germ tube branching was observed within 120 h, but no sporulation was observed within 240 h. The number of fluorescing epidermal cells was higher within 24 h in type i, and within 48-120 h in type ii resistance lines than in susceptible lines. Callose accumulation around the haustorium was detected in type ii resistance lines within 48-120 h. This suggests that the rapid hypersensitive response (HR) within 24 h has an important role in the type i response, while HR and callose accumulation in the type ii response occur slowly between 48 and 120 h. Of the resistant lines, PMR 45 and WMR 29 showed a type i incompatible response; the PI 414723 response was entirely type ii; and PMR 5, PI 124112, and MR-1 showed different responses depending on the race. Therefore, the two types of incompatible responses were intermixed in the same germplasm.

Stabilization of jaw-closing movements during chewing after correction of incisor crossbite.

Humans with normal occlusion usually perform gum-chewing movements in a characteristic manner. The purpose of present study was to examine whether the variability of masticatory jaw movement in children with incisor crossbite is greater than that in children with normal occlusions, and if so, to examine whether correction of the crossbite results in a significant reduction in the variability. The variance in masticatory jaw movement trajectory was investigated in 10 children with acceptable occlusion and 11 children with crossbite of one or two incisors. The lower incisor-point movements during chewing of standardized gum were monitored using a 3D tracking device. The deviation of the jaw-closing trajectory from a best-fit plane was then evaluated for each chewing cycle. Subsequently, variance in angles of the best-fit planes and variance in the instantaneous curvature of the jaw-closing trajectories were evaluated. Pitch angles of the best-fit planes and curvature of the trajectories during closing in patients were more variable than those in control subjects (P < 0.05). After treatment, the variances decreased significantly (P < 0.05). These findings suggest that the achievement of good occlusion is associated with a reduction of variability of jaw movements in a gum-chewing task.

Post-operative optimization of gum-chewing kinematics in a prognathic patient.

Smooth jaw movements during gum chewing, which are defined as those driven by optimally smooth patterns of temporal change in acceleration/deceleration, have been quantified in subjects with acceptable occlusions. This paper reports a case in which significant improvement of the smoothness of masticatory jaw movement was observed following surgical-orthodontic treatment. A patient, who demonstrated a mandibular prognathism, underwent the treatment. The irregularity in acceleration/deceleration of jaw closing movement during gum chewing was quantified by the movement jerk-cost, where the jerk is rate of change in movement acceleration/deceleration. The normalized jerk-costs and results of maximum-smoothness model simulation were compared between jaw movements at pre- and post-treatment stages. The correction of mandibular prognathism and crossbite allowed the patient to close the jaw with wider lateral excursion. Furthermore, smoothness of the jaw closing movements increased significantly and the velocity profile was characterized as similar to that predicted by the kinematic model after treatment. These findings for achievement of 'functional occlusion' that allows the patient to perform smooth and economical jaw closing movements during chewing demonstrate necessity of orthodontic treatment of mandibular prognathism to improve jaw motor function.

Powdery mildew (Sphaerotheca fuliginea) resistance in melon is selectable at the haploid level.

The major cause of powdery mildew in melons (Cucumis melo L.) is the fungus Sphaerotheca fuliginea. There are several cultivar- and season-specific races of this fungus. In order to control powdery mildew, it is important to introduce resistance to fungal infection into new cultivars during melon breeding. Haploid breeding is a powerful tool for the production of pure lines. In this study, it was investigated whether powdery mildew resistance could be manifested at the haploid level from two disease-resistant melon lines, PMR 45 and WMR 29. the effects of various races of S. fuliginea on diploid and haploid plants of PMR 45 and WMR 29 and of a disease-susceptible line, Fuyu 3 were measured. The responses of haploid and diploid plants to powdery mildew were identical. In addition, haploids that were generated from hybrids between Fuyu 3 and disease-resistant lines were examined. Seven out of 13 haploids from a Fuyu 3xPMR 45 cross and 10 out of 12 haploids from a Fuyu 3xWMR 29 cross were classified as resistant plants because they showed the same responses as their disease-resistant diploid parents to the various fungal races. These results indicate that resistance in PMR 45 and WMR 29 is selectable at the haploid level. All of the plant responses were observed by microscopy. A possible mechanism for generating powdery mildew resistance in two different melon lines is discussed.

Bioactive saponins and glycosides. XIX. Notoginseng (3): immunological adjuvant activity of notoginsenosides and related saponins: structures of notoginsenosides-L, -M, and -N from the roots of Panax notoginseng (Burk.) F. H. Chen.

New dammarane-type triterpene saponins, notoginsenosides-L, -M, and -N, were isolated from the glycosidic fraction of the dried roots of Panax notoginseng (Burk.) F. H. Chen. Their structures were elucidated on the basis of chemical and physicochemical evidence. Immunological adjuvant activities of the principal notoginsenosides and related dammarane-type triterpene saponins were examined and notoginsenosides-D, -G, -H, and -K were found to increase the serum IgG level in mice sensitized with ovalbumin.

Changes in masticatory jaw movement and muscle activity following surgical orthodontic treatment of an adult skeletal Class III case.

This case report examines the masticatory jaw movements and electromyograph (EMG) recordings of anterior and posterior temporal and masseter muscles before and after surgical orthodontic treatment in an adult patient with incisor crossbite and skeletal Class III jaw base relationship. The prescribed treatment resulted in a good occlusion and skeletal and dental Class I relationship. The chopping type jaw movement pattern during gum chewing was transformed to more of a grinding motion after treatment. But this motion was not as broad as is normally seen. This observation is indicative of the difficulties associated with improving the masticatory jaw movements in an adult patient to a completely normal pattern even after retention. In this patient, the high frequency of silent periods on the EMG that were observed in the early intercuspal phase before treatment were decreased to normal low levels after treatment. A similar decrease was also seen in the mean duration of the chewing cycle. We conjecture that this patient unsuccessfully attempted to compensate for the silent periods by increasing the period of his chewing cycle.

High-level production of recombinant chicken interferon-gamma by Brevibacillus choshinensis.

Cytokines, such as interferon-gamma have been shown to have adjuvant and growth promoting activity in poultry and livestock and have the potential to be used as alternatives to antibiotics. We have developed an efficient system for commercial-scale synthesis of recombinant chicken interferon-gamma (ChIFN-gamma) using Brevibacillus choshinensis as the host for protein production. The ChIFN-gamma expression vector, pNCIFN, was constructed using the novel Escherichia coli-B. choshinensis shuttle vector, pNCMO2. ChIFN-gamma expression was optimized by investigating different culture conditions and different host B. choshinensis mutants. The highest level of production was observed using the B. choshinensis HPD31-MB2 strain grown at 30 degrees C, where ChIFN-gamma was produced at approximately 300-500 mg/L. ChIFN-gamma was also produced as a His-tagged fusion protein by using the pNCHis-IFN expression vector, a derivative of pNCMO2. The protein was constitutively secreted into the culture supernatant and could be partially purified in a single step using a Ni-nitrilotriacetic acid column. This recombinant His-ChIFN-gamma was shown to have the same biological activity as native ChIFN-gamma.

Absence of aflatoxin biosynthesis in koji mold (Aspergillus sojae).

Ten strains isolated from industrial soy sauce producing koji mold were identified as Aspergillus sojae and distinguished from Aspergillus parasiticus morphologically and physiologically. There was no detectable aflatoxin in any culture extracts of A. sojae strains. Strain 477 was chosen as a representative strain of industrial A. sojae for further molecular analysis. All enzymatic activities associated with the aflatoxin biosynthesis were not detected or negligible in strain 477 compared with that of the A. parasiticus strain. Southern analysis suggested that the genomic DNA of strain 477 contained aflatoxin biosynthetic pathway genes. In contrast, all industrial strains lacked detectable transcripts of aflR, the main regulatory gene for aflatoxin biosynthesis, under the aflatoxin-inducing condition. Our data suggest that defects in aflR expression cause the lack of expression of aflatoxin-related genes which results in the absence of aflatoxin biosynthesis in A. sojae strains.