162 research outputs found
The structure of gravel-bed flow with intermediate submergence: a laboratory study
The paper reports an experimental study of the flow structure over an immobile gravel bed in open channel at intermediate submergence, with particular focus on the near-bed region. The experiments consisted of velocity measurements using three-component (stereoscopic) Particle Image Velocimetry (PIV) in near-bed horizontal plane and two-component PIV in three vertical planes that covered three distinctly different hydraulic scenarios where the ratio of flow depth to roughness height (i.e., relative submergence) changes from 7.5 to 10.8. Detailed velocity measurements were supplemented with fine-scale bed elevation data obtained with a laser scanner. The data revealed longitudinal low-momentum and high-momentum "strips'' in the time-averaged velocity field, likely induced by secondary currents. This depth-scale pattern was superimposed with particle-scale patches of flow heterogeneity induced by gravel particle protrusions. A similar picture emerged when considering second-order velocity moments. The interaction between the flow field and gravel-bed protrusions is assessed using cross correlations of velocity components and bed elevations in a horizontal plane just above gravel particle crests. The cross correlations suggest that upward and downward fluid motions are mainly associated with upstream-facing and lee sides of particles, respectively. Results also show that the relative submergence affects the turbulence intensity profiles for vertical velocity over the whole flow depth, while only a weak effect, limited to the near-bed region, is noticed for streamwise velocity component. The approximation of mean velocity profiles with a logarithmic formula reveals that log-profile parameters depend on relative submergence, highlighting inapplicability of a conventional "universal'' logarithmic law for gravel-bed flows with intermediate submergence
IoT sensors for modern structural health monitoring. A new frontier
The problem of determining the structural safety level of buildings and civil engineering infrastructures (CEIs) is raising growing concern worldwide. Most of the reinforced concrete constructions have a design life not greater than 100 years, and today it is necessary to face the problem of assessing their level of safety and structural integrity. Such problem is even more pressing when a construction is subjected to extreme environmental conditions. The long-term goal of this study is the realization of wireless low- cost devices, and a data management software, for the structural health monitoring of buildings and CEIs, with remotely controlled sensors embedded in, or installed on, the structural elements, to measure stresses together with accelerations. Once equipped with such system, each construction can become part of the Internet of Things, permitting users and authorities to be alerted in case structural safety is diminished or compromised. A crucial aspect is the unaltered preservation of measurement data over time, which cannot just rely on third parties, and for which it is necessary the exploitation of suitable data-protection technologies. This study have been carried out by experimental testing and validation, both in lab and on site, of the monitoring devices designed and realized. Results show that it is possible to realize low-cost monitoring systems, and related installation techniques, for integration in every new or existing buildings and CEIs
Impact of time to surgery after neoadjuvant chemotherapy in patients with operable breast cancer.
Background: Some studies of adjuvant chemotherapy (CT) suggested that a shorter interval before the start of therapies may
improve survival outcomes in many groups of patients. Time to surgery (TTS) after neoadjuvant CT and survival outcomes have
not been established yet. The aim of this study is to evaluate the impact of TTS after neoadjuvant CT in terms of Overall Survival
(OS) and Disease Free Survival (DFS).
Patients and Methods: A retrospective analysis was conducted in 295 patients receiving neoadjuvant CT for stage I-IIIc breast
cancer between 1991 and 2013. 56 pts underwent surgery within 21 days (group A) from last CT cycle, 148 pts within 22-35 days
(group B) and 91 pts after 36 days (group C). The majority were infiltrating ductal carcinoma, stage IIA (37.6%) and IIB
(33.9%), with nodal involvement in 51.6% of the cases. LumA 18.3%, LumB/HER2- 28.2%, LumB/Her2+ 20.7%, HER2+ 9.8%,
TNBC 21%. All patients were treated with neoadjuvant CT: 70.5% with anthra-taxanes based regimen, 18% with anthra- alone,
10.9% with taxanes alone, 0.3% with CMF; plus Trastuzumab in 70% of HER2+ diseases.
Results: After a median follow up of 4.6 years, it was observed that patients in group A showed a significant better OS than
group B (HR 4.22; 95% CI, 1.27 \u2013 14.00, p=0.018) and group C (HR 3.61; 95% CI, 1.01 \u2013 12.86, p=0.048). Moreover group A
showed a significant better DFS than group B (HR 3.41; 95% CI 1.34 to 8.65, p=0.010) and group C (HR 3.77; 95% CI 1.42 to
9.95, p=0.007).
No correlations with OS were found in pts who achieved pCR (20.7%); pCR was predictive of better 5- and 10-years DFS
independently from TTS (95.4% in the pCR-group vs 75.4% of non-pCR group, HR 0.16; 95% CI 0.04 to 0.66, p=0.011). TTS
may influence DFS in non-pCR group: indeed 5-years DFS is 97.3% in group A, 72.7% in group B (HR 2.89; 95% CI 1.14 to
7.36, p=0.026), and 68.5% in group C (HR 3.44; 95% CI 1.3 to 9.1, p=0.013). No significant correlations with regard of stage at
diagnosis or molecular subtypes were found.
Conclusions: These results suggest that TTS after primary CT may influence patients' survival, regardless of stage at diagnosis
and tumor subtype, so that a shorter interval between that last cycle of neoadjuvant chemotherapy and breast surgery should be
addressed whenever possible
Permanent monitoring of thin structures with low-cost devices
Recently, structural monitoring technology invested in methodologies that give direct information on structures' stress state. Optic fibers, strain gauges, pressure cells give real-time data on the stress condition of a structural element, often determining the area where peak stresses have been reached, with a clear advantage over other less direct monitoring methodologies, such as, e.g., the use of accelerometers and inverse analysis to estimate internal forces. In addition, stresses can be recorded in a data log for analysis after a loading event, as well as for taking into account the lifelong stress state of the structure. Beams and columns of a reinforced concrete frame can be effectively monitored for flexural loads. Differently, thin shells are most of their lifespan under membrane regime, and, when properly designed, they rarely move to the bending regime. Our proposal is to monitor the stress in thin structures by small-sized low- cost devices able to record the stress history at key locations, sending alerts when necessary, with the aim of ensuring safety against the risk of collapse, or simply to perform maintenance/repairing activities. Such devices are realized with cheap off-the-shelf electronics and traditional strain gauges. The application examples are given as laboratory tests performed on a reinforced concrete plate, a masonry panel, and a steel beam. Results shows that the permanent monitoring control of stresses can be conveniently carried out on new structures using low-cost devices of the type we designed and realized in-house
Development and Multicenter Validation of a Novel Immune-Inflammation-Based Nomogram to Predict Survival in Western Resectable Gastric and Gastroesophageal Junction Adenocarcinoma (GEA): The NOMOGAST
Background. More than 50% of operable GEA relapse after curative-intent resection. We aimed at externally validating a nomogram to enable a more accurate estimate of individualized risk in resected GEA. Methods. Medical records of a training cohort (TC) and a validation cohort (VC) of patients undergoing radical surgery for c/uT2-T4 and/or node-positive GEA were retrieved, and potentially interesting variables were collected. Cox proportional hazards in univariate and multivariate regressions were used to assess the effects of the prognostic factors on OS. A graphical nomogram was constructed using R software’s package Regression Modeling Strategies (ver. 5.0-1). The performance of the prognostic model was evaluated and validated. Results. The TC and VC consisted of 185 and 151 patients. ECOG:PS > 0 (p < 0.001), angioinvasion (p < 0.001), log (Neutrophil/Lymphocyte ratio) (p < 0.001), and nodal status (p = 0.016) were independent prognostic values in the TC. They were used for the construction of a nomogram estimating 3- and 5-year OS. The discriminatory ability of the model was evaluated with the c-Harrell index. A 3-tier scoring system was developed through a linear predictor grouped by 25 and 75 percentiles, strengthening the model’s good discrimination (p < 0.001). A calibration plot demonstrated a concordance between the predicted and actual survival in the TC and VC. A decision curve analysis was plotted that depicted the nomogram’s clinical utility. Conclusions. We externally validated a prognostic nomogram to predict OS in a joint independent cohort of resectable GEA; the NOMOGAST could represent a valuable tool in assisting decision-making. This tool incorporates readily available and inexpensive patient and disease characteristics as well as immune-inflammatory determinants. It is accurate, generalizable, and clinically effectivex
Early Detection of Prostate Cancer: The Role of Scent
Prostate cancer (PCa) represents the cause of the second highest number of cancer-related
deaths worldwide, and its clinical presentation can range from slow-growing to rapidly spreading
metastatic disease. As the characteristics of most cases of PCa remains incompletely understood, it
is crucial to identify new biomarkers that can aid in early detection. Despite the prostate-specific
antigen serum (PSA) levels, prostate biopsy, and imaging representing the actual gold-standard
for diagnosing PCa, analyzing volatile organic compounds (VOCs) has emerged as a promising
new frontier. We and other authors have reported that highly trained dogs can recognize specific
VOCs associated with PCa with high accuracy. However, using dogs in clinical practice has several
limitations. To exploit the potential of VOCs, an electronic nose (eNose) that mimics the dog olfactory
system and can potentially be used in clinical practice was designed. To explore the eNose as an
alternative to dogs in diagnosing PCa, we conducted a systematic literature review and meta-analysis
of available studies. PRISMA guidelines were used for the identification, screening, eligibility,
and selection process. We included six studies that employed trained dogs and found that the
pooled diagnostic sensitivity was 0.87 (95% CI 0.86–0.89; I2, 98.6%), the diagnostic specificity was
0.83 (95% CI 0.80–0.85; I2, 98.1%), and the area under the summary receiver operating characteristic
curve (sROC) was 0.64 (standard error, 0.25). We also analyzed five studies that used an eNose to
diagnose PCa and found that the pooled diagnostic sensitivity was 0.84 (95% CI, 0.80–0.88; I2, 57.1%),
the diagnostic specificity was 0.88 (95% CI, 0.84–0.91; I2, 66%), and the area under the sROC was
0.93 (standard error, 0.03). These pooled results suggest that while highly trained dogs have the
potentiality to diagnose PCa, the ability is primarily related to olfactory physiology and training
methodology. The adoption of advanced analytical techniques, such as eNose, poses a significant
challenge in the field of clinical practice due to their growing effectiveness. Nevertheless, the presence
of limitations and the requirement for meticulous study design continue to present challenges when
employing eNoses for the diagnosis of PCa
Cancer initiation and progression: an unsimplifiable complexity
BACKGROUND: Cancer remains one of the most complex diseases affecting humans and, despite the impressive advances that have been made in molecular and cell biology, how cancer cells progress through carcinogenesis and acquire their metastatic ability is still widely debated. CONCLUSION: There is no doubt that human carcinogenesis is a dynamic process that depends on a large number of variables and is regulated at multiple spatial and temporal scales. Viewing cancer as a system that is dynamically complex in time and space will, however, probably reveal more about its underlying behavioural characteristics. It is encouraging that mathematicians, biologists and clinicians continue to contribute together towards a common quantitative understanding of cancer complexity. This way of thinking may further help to clarify concepts, interpret new and old experimental data, indicate alternative experiments and categorize the acquired knowledge on the basis of the similarities and/or shared behaviours of very different tumours
Combined low densities of FoxP3+ and CD3+ tumor-infiltrating lymphocytes identify stage II colorectal cancer at high risk of progression
The densities of CD3+ and CD8+ tumor-infiltrating lymphocytes (TILs), combined with TNM (tumor-node-metastasis) staging, have prognostic value for nonmetastatic colorectal cancer (CRC) patients. We compared the prognostic value of CD3+ and FoxP3+ TILs at the invasive front, TNM classifiers, and microsatellite (MS) status in a trial set of patients with stage II-III CRC (n = 413), by recursive partitioning with a classification and regression tree (CART). Significant prognostic factors and interactions were re-assessed by logistic regression and Cox proportional-hazards modeling in the trial and a validation set (n = 215) of patients with stage II CRC. In the trial set, CART indicated that TIL numbers were of value only in predicting recurrence risk for stage II cancers, where low densities of FoxP3+ TILs ranked first and low densities of CD3+ TILs further stratifiying risk. Multivariate analysis showed that TILs interacted with tumor stage (FoxP3+, P = 0.06; CD3+, P = 0.02) and MS instability (FoxP3+; P = 0.02). In stage II MS-stable cancers, concomitant low densities of both FoxP3+ and CD3+ TILs identified patients with the highest progression risk in the trial (HR 7.24; 95%CI, 3.41-15.4; P < 0.001) and the validation (HR 15.16; 95% IC, 3.43-66.9; P < 0.001) sets. FoxP3+ and CD3+ TIL load in CRC was more informative than other prognostic factors before the cancer progressed to lymph nodes. This prognostic information about TILs, including FoxP3+ cells, suggests that randomized controlled trials might be refined to include interactions between TNM status, molecular classifiers, and post-surgical treatments
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