AERATION AND MIXING BEHAVIOURS OF BINARY MIXTURES OF NANO-SIZED POWDERS UNDER SOUND VIBRATION

The aeration behaviour of three different nano-sized powders, Al2O3, Fe2O3 and CuO, fluidized under the application of acoustic fields of different intensities (125-150 dB) and frequencies (50-300 Hz) has been characterized. The characterization of the fluidization of binary mixtures of Al2O3 and Fe2O3 has been also investigated under the application of acoustic fields of 120 Hz and of two different intensities, 130 and 135 dB, and varying the relative amount of two powders from 17 to 50 %wt of Fe2O3. The addition of Fe2O3 has a beneficial effect on fluidization quality of Al2O3 even for the lowest amount of Fe2O3. Under the effect of sound, mixing between Al2O3 and CuO nanopowders has been also quantitatively characterized by the Scanning Electron Microscopy with X-ray microanalysis (SEM/EDS) analysis of captured samples. Mixing between aggregates of the two powders takes only few minutes. However, mixing also occurs inside aggregates but this process requires times of the order of 80-150 minutes, depending on the feeding order of two powders

Role of Sound Vibration during Aeration of Nano-Sized Powders

The behaviour of two different nano-sized powders, Al2O3 (40 nm) and SiO2 (15 nm), during aeration has been investigated in a laboratory scale fluidized bed. The fluidization quality of both powders is very poor without application of acoustic fields even if some bed expansion has been found. The application of acoustic fields of intensities larger than 135 dB and frequencies close to 120 Hz is able to increase the fluidization quality of both powders. Sound is also able to promote an apparent self-fluidization of a relatively thin portion of the upper part of the bed. The possibility that there is an efficient mixing between aggregates during aeration has been highlighted by experiments using a tracer powder

HYDRODYNAMICS OF UNCONVENTIONAL FLUIDIZED BEDS: SOLIDS FLOW PATTERNS AND THEIR INFLUENCE ON MIXING/SEGREGATION OF A LARGE FLOTSAM PARTICLE IN A BED OF FINER SOLIDS

Gross solids circulation of solid phase and its influence on mixing/segregation of a large flotsam particle in beds of finer solids in unconventional fluidized beds has been investigated. A tapered two-dimensional fluidization column and a fluidization column equipped with a diverging cone as gas distributor have been adopted. The hydrodynamics of the gas-solid suspension in the two apparatus has been qualitatively assessed by visual observation and the trajectories of the centre-of-gravity of large flotsam particles have been evaluated to assess the extent of mixing/segregation

Mast cells, microRNAs and others: The role of translational research on colorectal cancer in the forthcoming era of precision medicine

Colorectal cancer (CRC) is a heterogeneous disease, molecularly and anatomically, that develops in a multi-step process requiring the accumulation of several genetic or epigenetic mutations that lead to the gradual transformation of normal mucosa into cancer. In fact, tumorigenesis is extremely complex, with many immunologic and non-immunologic factors present in the tumor microenvironment that can influence tumorigenesis. In the last few years, a role for mast cells (MCs), microRNAs (miRNAs), Kirsten rat sarcoma (KRAS) and v-raf murine sarcoma viral oncogene homologue B (BRAF) in cancer development and progression has been suggested, and numerous efforts have been made to thoroughly assess their correlation with CRC to improve patient survival and quality of life. The identification of easily measurable, non-invasive and cost-effective biomarkers, the so-called “ideal biomarkers”, for CRC screening and treatment remains a high priority. The aim of this review is to discuss the emerging role of mast cells (MCs), microRNAs (miRNAs), KRAS and BRAF as diagnostic and prognostic biomarkers for CRC, evaluating their influence as potential therapy targets in the forthcoming era of precision medicine

Intraventricular Meningiomas: Clinical-Pathological and Genetic Features of a Monocentric Series

Intraventricular meningiomas (IVMs) are rare (0.5-5%) and usually low-grade (90% grade I) brain neoplasms. Their recurrence rate is lower than that of extra-axial meningiomas, but their surgical resection can be burdened with life-threatening complications, which represent the major cause of the reported 4% mortality. The aim of this study is to characterize the molecular portrait of IVMs to identify potential therapeutic targets. For this, we explored mutations and copy number variations (CNV) of 409 cancer-related genes and tumor mutational burden (TMB) of six cases, using next-generation sequencing. Five IVMs were grade I and one was grade II; none recurred, in spite of partial surgical resection in one case. NF2 mutation was the only recurring alteration and was present in three of the six IVMs, in association with SMARCB1 mutation in one case. None of the cases was hypermutated (TMB > 10 mutations/Mb). NF2-mutant progressing or recurring IVMs could potentially be treated with targeted therapies applied to other NF2-mutant tumors, as an alternative to surgery or radiosurgery, while in view of their low TMB they are unlikely candidates to immune check-point inhibition

The Immunohistochemical Loss of H3K27me3 in Intracranial Meningiomas Predicts Shorter Progression-Free Survival after Stereotactic Radiosurgery

The immunohistochemical loss of histone H3 trimethylated in lysine 27 (H3K27me3) was recently shown to predict recurrence of meningiomas after surgery. However, its association with tumor progression after stereotactic radiosurgery (SRS) is unexplored. To investigate whether H3K27 methylation status may predict progression-free survival (PFS) after SRS, we assessed H3K27me3 immunoexpression in thirty-nine treatment naïve, intracranial, meningiomas, treated with surgery and subsequent SRS for residual (twenty-three cases) or recurrent (sixteen cases) disease. H3K27me3 immunostaining was lost in seven meningiomas, retained in twenty-seven and inconclusive in five. Six of the seven meningiomas (86%) with H3K27me3 loss had tumor progression after SRS, compared to nine of twenty-seven (33%) with H3K27me3 retention (p = 0.0143). In addition, patients harboring a meningioma with H3K27me3 loss had significantly shorter PFS after SRS (range: 10-81 months; median: 34 months), compared to patients featuring a meningioma with retained H3K27me3 (range: 9-143 months; median: 62 months) (p = 0.0036). Nonetheless, tumor sagittal location was the only significant prognostic variable at multivariate analysis for PFS after SRS (p = 0.0142). These findings suggest a previously unreported role of H3K27me3 as a predictor of meningioma progression after SRS for recurrent or residual disease. Modulation of H3K27 methylation status may represent a novel therapeutic strategy to induce radiosensitization of meningiomas

Training curriculum in minimally invasive emergency digestive surgery : 2022 WSES position paper

Background Minimally invasive surgery (MIS), including laparoscopic and robotic approaches, is widely adopted in elective digestive surgery, but selectively used for surgical emergencies. The present position paper summarizes the available evidence concerning the learning curve to achieve proficiency in emergency MIS and provides five expert opinion statements, which may form the basis for developing standardized curricula and training programs in emergency MIS. Methods This position paper was conducted according to the World Society of Emergency Surgery methodology. A steering committee and an international expert panel were involved in the critical appraisal of the literature and the development of the consensus statements. Results Thirteen studies regarding the learning curve in emergency MIS were selected. All but one study considered laparoscopic appendectomy. Only one study reported on emergency robotic surgery. In most of the studies, proficiency was achieved after an average of 30 procedures (range: 20-107) depending on the initial surgeon's experience. High heterogeneity was noted in the way the learning curve was assessed. The experts claim that further studies investigating learning curve processes in emergency MIS are needed. The emergency surgeon curriculum should include a progressive and adequate training based on simulation, supervised clinical practice (proctoring), and surgical fellowships. The results should be evaluated by adopting a credentialing system to ensure quality standards. Surgical proficiency should be maintained with a minimum caseload and constantly evaluated. Moreover, the training process should involve the entire surgical team to facilitate the surgeon's proficiency. Conclusions Limited evidence exists concerning the learning process in laparoscopic and robotic emergency surgery. The proposed statements should be seen as a preliminary guide for the surgical community while stressing the need for further research.Peer reviewe

Diversity and ethics in trauma and acute care surgery teams: results from an international survey

Background Investigating the context of trauma and acute care surgery, the article aims at understanding the factors that can enhance some ethical aspects, namely the importance of patient consent, the perceptiveness of the ethical role of the trauma leader, and the perceived importance of ethics as an educational subject. Methods The article employs an international questionnaire promoted by the World Society of Emergency Surgery. Results Through the analysis of 402 fully filled questionnaires by surgeons from 72 different countries, the three main ethical topics are investigated through the lens of gender, membership of an academic or non-academic institution, an official trauma team, and a diverse group. In general terms, results highlight greater attention paid by surgeons belonging to academic institutions, official trauma teams, and diverse groups. Conclusions Our results underline that some organizational factors (e.g., the fact that the team belongs to a university context or is more diverse) might lead to the development of a higher sensibility on ethical matters. Embracing cultural diversity forces trauma teams to deal with different mindsets. Organizations should, therefore, consider those elements in defining their organizational procedures. Level of evidence Trauma and acute care teams work under tremendous pressure and complex circumstances, with their members needing to make ethical decisions quickly. The international survey allowed to shed light on how team assembly decisions might represent an opportunity to coordinate team member actions and increase performance

Infected pancreatic necrosis: outcomes and clinical predictors of mortality. A post hoc analysis of the MANCTRA-1 international study

: The identification of high-risk patients in the early stages of infected pancreatic necrosis (IPN) is critical, because it could help the clinicians to adopt more effective management strategies. We conducted a post hoc analysis of the MANCTRA-1 international study to assess the association between clinical risk factors and mortality among adult patients with IPN. Univariable and multivariable logistic regression models were used to identify prognostic factors of mortality. We identified 247 consecutive patients with IPN hospitalised between January 2019 and December 2020. History of uncontrolled arterial hypertension (p = 0.032; 95% CI 1.135-15.882; aOR 4.245), qSOFA (p = 0.005; 95% CI 1.359-5.879; aOR 2.828), renal failure (p = 0.022; 95% CI 1.138-5.442; aOR 2.489), and haemodynamic failure (p = 0.018; 95% CI 1.184-5.978; aOR 2.661), were identified as independent predictors of mortality in IPN patients. Cholangitis (p = 0.003; 95% CI 1.598-9.930; aOR 3.983), abdominal compartment syndrome (p = 0.032; 95% CI 1.090-6.967; aOR 2.735), and gastrointestinal/intra-abdominal bleeding (p = 0.009; 95% CI 1.286-5.712; aOR 2.710) were independently associated with the risk of mortality. Upfront open surgical necrosectomy was strongly associated with the risk of mortality (p < 0.001; 95% CI 1.912-7.442; aOR 3.772), whereas endoscopic drainage of pancreatic necrosis (p = 0.018; 95% CI 0.138-0.834; aOR 0.339) and enteral nutrition (p = 0.003; 95% CI 0.143-0.716; aOR 0.320) were found as protective factors. Organ failure, acute cholangitis, and upfront open surgical necrosectomy were the most significant predictors of mortality. Our study confirmed that, even in a subgroup of particularly ill patients such as those with IPN, upfront open surgery should be avoided as much as possible. Study protocol registered in ClinicalTrials.Gov (I.D. Number NCT04747990)