On equitably 2-colourable odd cycle decompositions

An l-cycle decomposition of K_v is said to be equitably 2-colourable if there is a 2-vertex-colouring of K_v such that each colour is represented (approximately) an equal number of times on each cycle: more precisely, we ask that in each cycle C of the decomposition, each colour appears on (l-1)/2 (floor) or (l-1)/2 (ceiling) of the vertices of C. In this paper we study the existence of equitably 2-colourable l -cycle decompositions of K_v, where l is odd, and prove the existence of such a decomposition for v=1,l (mod (2l))

Cyclic cycle systems of the complete multipartite graph

In this paper, we study the existence problem for cyclic $\ell$-cycle decompositions of the graph $K_m[n]$, the complete multipartite graph with $m$ parts of size $n$, and give necessary and sufficient conditions for their existence in the case that $2\ell \mid (m-1)n$

The Use of Barbed Suture for Intracorporeal Mechanical Anastomosis During a Totally Laparoscopic Right Colectomy: Is It Safe? A Retrospective Nonrandomized Comparative Multicenter Study

Background. A totally laparoscopic right colectomy could be perceived as a more challenging procedure over a laparoscopic-assisted right colectomy owing to the difficulty of intracorporeal anastomosis and the closure of the enterotomy. The aim of this study is to evaluate the safety and efficacy of the barbed auto-locking absorbable suture for the closure of an anastomotic stapler-access enterotomy during a totally laparoscopic right colectomy. Methods. From January 2010 to April 2016, data from patients who had undergone a laparoscopic right colectomy in 2 different departments of 2 institutions (the Department of General and Minimally Invasive Surgery, San Camillo Hospital in Trento and the Department of Surgical Specialties and Nephrology, University Federico II in Naples) were retrospectively analyzed. We compared the data of patients in whom the stapler-access enterotomy was closed through a conventional absorbable suture (Group A), with the data of patients in whom a stapler-access enterotomy was closed through a V-Loc 180 suture (Group B). Biometric features and intraoperative and postoperative data were collected and analyzed. Results. The 2 groups (Group A: 40 patients; Group B: 40 patients) were comparable for biometric features and postoperative outcomes. The anastomosing time was lower in Group B. A statistically significant difference was noted in the mean operative time between Groups A and B (Group A = 134.92 ± 34.17; Group B = 120.92 ± 23.27, P =.035). Only one anastomotic leakage per group was recorded, each treated with an anastomosis redo. During the reoperations, we find in both groups an intact stapler-access enterotomy. Conclusion. On retrospective analysis, barbed suture appears to be safe and efficient for closure of the stapler-access enterotomy during totally laparoscopic right colectomy

Validation of a model of the GAL regulatory system via robustness analysis of its bistability characteristics

In Saccharomyces cerevisiæ, structural bistability generates a bimodal expression of the galactose uptake genes (GAL) when exposed to low and high glucose concentrations. This indicates that yeast cells can decide between using either the limited amount of glucose or growing on galactose under changing environmental conditions. A crucial requirement for any plausible mechanistic model of this system is that it reproduces the robustness of the bistable response observed in vivo against inter-individual parametric variability and fluctuating environmental conditions

Red blood cell as an adaptive optofluidic microlens

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Effect of coil charge duration on combustion variability and flame morphology in a GDI engine working in lean burn conditions

Spark ignition (SI) and subsequent flame front development exert a significant influence on cyclic variability of internal combustion engines (ICEs). The increasing exploitation of lean air-fuel mixtures in SI engines to lower fuel consumption and CO2 emissions is driving the scientific community towards the search for innovative combustion strategies. Moreover, although lean combustion has been widely investigated and an important number of studies is already present in literature, the high cyclic variability typical of this combustion process still represents a major hinder to its exploitation. This study aims to investigate the effects of increasing ignition energy on combustion characteristics of lean mixtures. Tests were performed on an optically accessible gasoline direct injection (GDI) engine that allowed to investigate the correlation between the thermodynamic results and spark arc-flame morphology. Engine speed was fixed at 2000 rpm, a relative air fuel ratio (AFRrel) of about 1.3 was selected and ignition timing was set at 12 crank angle degrees (CAD) bTDC. Coil charge duration was swept from 10 to 40 CAD. Two intake pressure levels were investigated, the first corresponding to wide open throttle under naturally aspirated operating mode, the second with an intake pressure of 1.2 bar, thus corresponding to a boosted operating condition. Two dedicated scripts built using NI Vision were employed for image processing, allowing the evaluation of temporal and spatial evolution of the early stages of combustion. Arc elongation and flame front contour were used as correlation parameters that characterize flame kernel inception and development. The results confirm that, as expected, the increase of the coil charge duration tends to reduce cyclic variability in terms of engine output. The optical investigations revealed that for both examined cases the standard deviation related to the wrinkling effect on flame edge at CA5 decreased as the coil charge duration increased

A Novel Hierarchy of Integrable Lattices

In the framework of the reduction technique for Poisson-Nijenhuis structures, we derive a new hierarchy of integrable lattice, whose continuum limit is the AKNS hierarchy. In contrast with other differential-difference versions of the AKNS system, our hierarchy is endowed with a canonical Poisson structure and, moreover, it admits a vector generalisation. We also solve the associated spectral problem and explicity contruct action-angle variables through the r-matrix approach.Comment: Latex fil

Design, Computational Modelling and Experimental Characterization of Bistable Hybrid Soft Actuators for a Controllable-Compliance Joint of an Exoskeleton Rehabilitation Robot

This paper presents the mechatronic design of a biorobotic joint with controllable compliance, for innovative applications of “assist-as-needed” robotic rehabilitation mediated by a wearable and soft exoskeleton. The soft actuation of robotic exoskeletons can provide some relevant advantages in terms of controllable compliance, adaptivity and intrinsic safety of the control performance of the robot during the interaction with the patient. Pneumatic Artificial Muscles (PAMs), which belong to the class of soft actuators, can be arranged in antagonistic configuration in order to exploit the variability of their mechanical compliance for the optimal adaptation of the robot performance during therapy. The coupling of an antagonistic configuration of PAMs with a regulation mechanism can achieve, under a customized control strategy, the optimal tuning of the mechanical compliance of the exoskeleton joint over full ranges of actuation pressure and joint rotation. This work presents a novel mechanism, for the optimal regulation of the compliance of the biorobotic joint, which is characterized by a soft and hybrid actuation exploiting the storage/release of the elastic energy by bistable Von Mises elastic trusses. The contribution from elastic Von Mises structure can improve both the mechanical response of the soft pneumatic bellows actuating the regulation mechanism and the intrinsic safety of the whole mechanism. A comprehensive set of design steps is presented here, including the optimization of the geometry of the pneumatic bellows, the fabrication process through 3D printing of the mechanism and some experimental tests devoted to the characterization of the hybrid soft actuation. The experimental tests replicated the main operating conditions of the regulation mechanism; the advantages arising from the bistable hybrid soft actuation were evaluated in terms of static and dynamic performance, e.g., pressure and force transition thresholds of the bistable mechanism, linearity and hysteresis of the actuator response

Laparoscopic treatment of abdominal unicentric castleman's disease: a case report and literature review.

BACKGROUND: Castleman's disease is a rare lymphoproliferative disorder of unknown etiology that most commonly presents as a mediastinal nodal mass. It is exceptionally uncommon for Castleman's disease to present in the mesentery and, only 53 cases have ever been described in the literature. Standard treatment for this lymphoproliferative disorder involving a single node is a complete "en bloc" surgical resection which has proven to be a curative approach in almost all cases without recurrence after 20 years of follow up. All 53 reported cases of mesenteric Castleman's disease, except one, were treated with laparotomy. CASE PRESENTATION: We report on a case of mesenteric Castleman's disease localized in the mesentery which is the second reported case if its kind and was treated by a laparoscopic-assisted procedure. Our female patient had an uneventful postoperative course and was discharged in the 5th post-operative day. No signs of recurrence were present as evidenced by physical examination and total body CT scan 24 months after the operation. We compare our case with the other reported cases in which Castleman's disease presented as an isolated mass in the abdomen. CONCLUSION: Although a rare disease, Unicentric Castleman's disease should always be considered when a solid asymptomatic abdominal mass is occasionally presented. The laparoscopic approach (LA) allows for the achievement of better results than open surgery, including a reduction in postoperative pain and length of hospital stay. In cases of masses of an uncertain nature, LA must be considered the last diagnostic tool and the first treatment one