Balanced and strongly balanced Pk-designs

AbstractGiven a graph G, a G-decomposition of the complete graph Kv is a set of graphs, all isomorphic to G, whose edge sets partition the edge set of Kv. A G-decomposition of Kv is also called a G-design and the graphs of the partition are said to be the blocks. A G-design is said to be balanced if the number of blocks containing any given vertex of Kv is a constant.In this paper the concept of strongly balanced G-design is introduced and strongly balanced path-designs are studied. Furthermore, we determine the spectrum of those path-designs which are balanced, but not strongly balanced

Occupational Risk Assessment in Landfills. Research Outcomes from Italy

Industrial production has brought increased wellbeing in the last years, but the amount of solid waste has undoubtedly increased. Thus, open dumpsites and landfills have been created throughout the world, with serious impacts on the environment and public health. In such a context, occupational health and safety (OHS) issues related to workers that have to deal with landfill characterization or management have not been considered sufficiently. To reduce such a research gap, in 2019 a research project started in Italy on OHS risk assessment in landfills. In fact, in such facilities, workers can be subjected to direct contact with the polluted environment and might not be completely aware of the entity and type of pollution (e.g., in open dumpsites). Starting with the analysis of INAIL data on accidents at work which occurred in Italy during the period 2008–2019, a specific risk analysis was carried out with the goal of defining risk determinants and profiles by means of K-means cluster analysis. Such an analysis allowed us to recognize the use of work equipment and the work environment as the main determinants of the accidents on the one hand, and the “driver of the excavator” as the most risky activity on the other. The achieved results take a step forward towards the characterization of occupational health and safety issues in landfills. Accordingly, the research outcomes represent a basis on which to address further research work in this field

Modified pseudo-elastic approach for modelling cyclic response of biological heart valves

A modified pseudo-elastic approach is proposed to model cyclic response on biological heart valves. The model takes into account hysteretic effects, in combination with hyperelastic anisotropic behaviour of valve leaflets, allowing reproduction of different loading and unloading paths. FEM implementation considered a biological heart valve during the closure phase

Role of docetaxel in the treatment of advanced gastric carcinoma

With a median survival of 9-11 months, advanced gastric cancer represents one of the most aggressive neoplastic disease in western Countries. Radical surgery is considered the cornerstone for any curative procedure, however only a relatively small proportion of resected cases can be considered cured after surgery. In the last few years research data suggested that advanced gastric cancer can be classified into 2 distinct clinical categories: locally advanced (nonmetastatic, non resectable) and metastatic. While the therapeutic goal in the metastatic setting is palliation and survival improvement, in locally advanced cases one of the main goals of the treatment should be response with the aim to make resectable what was unresectable. The introduction of docetaxel for the treatment of advanced gastric cancer represented then a crucial step forward for the cure of this disease with an improvement in both survival and response rate. In this article we reviewed past and ongoing trials using docetaxel in gastric cancer with the aim to delineate a possible effective strategy for the treatment of this tumou

Lessons from the COVID-19 pandemic: remote coaching in bariatric surgery

Background: The development of fast internet connection has stimulated different types of video-assisted teaching programs. However, a remote mentoring with the proctor not on site has never been reported in bariatric surgery. We described our experiences with remote telementoring for laparoscopic sleeve gastrectomy. Methods: A qualified general surgeon at the beginning of his bariatric practice performed a series of 8 laparoscopic sleeve gastrectomies (LSG) while tutored by an experienced bariatric surgeon connected from a different city through a specific videoconferencing platform. Data on demographics at baseline, operative time, hospital stay, intraoperative early, and late complications were collected. Results: Mean age and BMI of patients were 36.9 ± 9.6 years old and 41.8 ± 1.7 kg/m2. All procedures were carried out without conversion to open or complications. Mean operative time was 112.4 ± 21.9 min while the hospital stay was 3.5 ± 0.5 days. Operative time significantly decreased after the fourth operation. Conclusions: Remote coaching appears to be possible and safe for LSG

Safety and efficacy of OAGB/MGB during the learning curve: setting a benchmark in a bariatric center of excellence

: Very little has been published on the learning curve (LC) of the One Anastomosis /Mini Gastric Bypass (OAGB/MGB). Aim of this study was to compare perioperative outcomes of OABG/MGBs performed during the LC of an experienced laparoscopic surgeon to global benchmark cut-offs. First 200 patients undergoing OAGB/MGB at our university hospital from 2010 to 2016 were retrospectively included in this study. LC of the surgeon was divided in two groups of 100 consecutive patients each and perioperative outcomes were compared to abovementioned global benchmarks for LSG and RYGB. A cumulative sum (CUSUM) analysis was performed for operative time and hospital stay. Uneventful postoperative recovery was recorded in 95% of patients. All benchmark values for RYGB were met in group 2. Comparison with cut-offs for LSG showed longer hospital stay and operative time in both groups but postoperative rate of complications resulted lower even for Group 1. CUSUM graph of the operative time runs randomly above the predetermined limit till the 40th cases but reaches the plateau after the 115th operation. CUSUM curve of the hospital stay reaches the plateau after the 57th case. OAGB/MGB confirms to be a feasible procedure, which can be safely and effectively performed during the learning curve. However, at least 100 hundred cases are required to reduce operative time and hospital stay

Perfect Octagon Quadrangle Systems with an upper C4-system and a large spectrum

An octagon quadrangle is the graph consisting of an 8-cycle (x1, x2,..., x8) with two additional chords: the edges {x1, x4} and {x5, x8}. An octagon quadrangle system of order ν and index λ [OQS] is a pair (X,H), where X is a finite set of ν vertices and H is a collection of edge disjoint octagon quadrangles (called blocks) which partition the edge set of λKν defined on X. An octagon quadrangle system Σ=(X,H) of order ν and index λ is said to be upper C4-perfect if the collection of all of the upper 4-cycles contained in the octagon quadrangles form a μ-fold 4-cycle system of order ν; it is said to be upper strongly perfect, if the collection of all of the upper 4-cycles contained in the octagon quadrangles form a μ-fold 4-cycle system of order ν and also the collection of all of the outside 8-cycles contained in the octagon quadrangles form a ρ-fold 8-cycle system of order ν. In this paper, the authors determine the spectrum for these systems, in the case that it is the largest possible

Panitumumab: the evidence for its use in the treatment of metastatic colorectal cancer

Panitumumab is the first fully human monoclonal antibody to Epidermal Growth Factor Receptor (EGFR) to enter clinical trials for the treatment of solid tumors. The anti-tumor activity of panitumumab has been tested in vitro and in vivo, and inhibition of tumor growth has been observed in numerous cancer models, particularly lung, kidney and colorectal (CRC). Preclinical and clinical studies have established a role for panitumumab in metastatic colorectal cancer (mCRC) refractory to multiple chemotherapeutic regimens. Based on these encouraging findings, panitumumab was approved by the US Food and Drug Administration for the treatment of patients with epidermal growth factor receptor-expressing mCRC refractory to fluoropyrimidine-, oxaliplatin-, and/or irinotecan-containing chemotherapeutic regimens. The improvement in progression free survival (PFS) and response rate (RR) produced by panitumumab monotherapy was significantly greater in patients with non mutated (wild-type) K-RAS than in those with mutant K-RAS. Therefore implementing routine K-RAS screening and limiting the use of EGFR inhibitors to patients with wild-type K-RAS appears the better strategy for select only the patients who could benefit from the therapy with panitumumab and also may have the potential for cost savings. The purpose of this review was to evaluate the patient-related, disease-related and economic-related evidence for the use of panitumumab in the treatment of metastatic colorectal cancer in clinical practice

Vitamin D Deficiency in Patients with Morbid Obesity before and after Metabolic Bariatric Surgery

Background: Metabolic bariatric surgery (MBS) is the most effective treatment for severe obesity. Vitamin D deficiency is a common complication encountered both during preoperative workup and follow-up. Aim: To estimate the prevalence of vitamin D deficiency in patients undergoing MBS. Methods: Prospectively maintained database of our university MBS center was searched to assess the rate of preoperative and postoperative vitamin D deficiency or insufficiency in patients undergoing MBS over a one-year period. Results: In total, 184 patients were included, 85 cases of Sleeve Gastrectomy (SG), 99 Gastric Bypass (GB; 91 One Anastomosis and 8 Roux-en-Y). Preoperative vitamin D deficiency and insufficiency were respectively found in 61% and 29% of patients, with no significant difference between SG and GB. After six months, 15% of patients had vitamin D deficiency, and 34% had vitamin D insufficiency. There was no significant difference in the rate of vitamin D deficiency or insufficiency and the percentage of total weight loss (%TWL) at 1, 3, and 6 postoperative months between SG and GB. Conclusions: Preoperative vitamin D deficiency or insufficiency is common in MBS candidates. Regular follow-up with correct supplementation is recommended when undergoing MBS. Early postoperative values of vitamin D were comparable between SG and OAGB

New techniques versus standard mapping for sentinel lymph node biopsy in breast cancer: a systematic review and meta-analysis

: New tracers for sentinel lymph node biopsy (SLNB), as indocyanine green (ICG), superparamagnetic iron oxide (SPIO) and micro bubbles, have been recently introduced in clinical practice showing promising but variable results. We reviewed the available evidence comparing these new techniques with the standard tracers to evaluate their safety. To identify all available studies, a systematic search was performed in all electronic databases. Data regarding sample size, mean number of SLN harvested for patient, number of metastatic SLN and SLN identification rate of all studies were extracted. No significant differences were found in terms of SLNs identification rates between SPIO, RI and BD but with a higher identification rate with the use of ICG. No significant differences were also found for the number of metastatic lymph nodes identified between SPIO, RI and BD and the mean number of SLNs identified between SPIO and ICG versus conventional tracers. A statistically significant differences in favor of ICG was reported for the comparison between ICG and conventional tracers for the number of metastatic lymph nodes identified. Our meta-analysis demonstrates that the use of both ICG and SPIO for the pre-operative mapping of sentinel lymph nodes in breast cancer treatment is adequately effective