We present turbulent Schmidt number (
S
c
t
) estimations above three-dimensional urban canopies, where
S
c
t
is a property of the flow defined as the ratio of the eddy diffusivity of momentum (
K
M
...) to the eddy diffusivity of mass (
D
t
). Despite the fact that
S
c
t
modelling is of great interest, inter alia, for pollutant dispersion simulations conducted via computational fluid dynamics, no universal value is known. Simultaneous measurements of fluid velocity and mass concentration are carried out in a water channel for three staggered arrays of cubical obstacles corresponding to isolated flow, wake-interference, and skimming-flow regimes. A passive tracer is released from a continuous point source located at a height
z
=
1.67
H
where
H
is the obstacle height. The results show an increase of
S
c
t
with height above the canopy for all three arrays, with values at
z
=
2
H
(
S
c
t
≈
0.6
) about double compared to that at
z
=
H
. The observed
S
c
t
agrees well with that modelled by using a simple formulation for
S
c
t
based on expressions for
K
M
and
D
t
published in previous studies. Comparisons with other
S
c
t
models found in the literature are also presented and discussed.
All over the world, the rapid urbanization process is challenging the sustainable development of our cities. In 2015, the United Nation highlighted in Goal 11 of the SDGs (Sustainable Development ...Goals) the importance to “Make cities inclusive, safe, resilient and sustainable”. In order to monitor progress regarding SDG 11, there is a need for proper indicators, representing different aspects of city conditions, obviously including the Land Cover (LC) changes and the urban climate with its most distinct feature, the Urban Heat Island (UHI). One of the aspects of UHI is the Surface Urban Heat Island (SUHI), which has been investigated through airborne and satellite remote sensing over many years. The purpose of this work is to show the present potential of Google Earth Engine (GEE) to process the huge and continuously increasing free satellite Earth Observation (EO) Big Data for long-term and wide spatio-temporal monitoring of SUHI and its connection with LC changes. A large-scale spatio-temporal procedure was implemented under GEE, also benefiting from the already established Climate Engine (CE) tool to extract the Land Surface Temperature (LST) from Landsat imagery and the simple indicator Detrended Rate Matrix was introduced to globally represent the net effect of LC changes on SUHI. The implemented procedure was successfully applied to six metropolitan areas in the U.S., and a general increasing of SUHI due to urban growth was clearly highlighted. As a matter of fact, GEE indeed allowed us to process more than 6000 Landsat images acquired over the period 1992–2011, performing a long-term and wide spatio-temporal study on SUHI vs. LC change monitoring. The present feasibility of the proposed procedure and the encouraging obtained results, although preliminary and requiring further investigations (calibration problems related to LST determination from Landsat imagery were evidenced), pave the way for a possible global service on SUHI monitoring, able to supply valuable indications to address an increasingly sustainable urban planning of our cities.
Due to its importance in airborne disease transmission, especially because of the COVID-19 pandemic, much attention has recently been devoted by the scientific community to the analysis of dispersion ...of particle-laden air clouds ejected by humans during different respiratory activities. In spite of that, a lack of knowledge is still present particularly with regard to the velocity of the emitted particles, which could differ considerably from that of the air phase. The velocity of the particles is also expected to vary with their size. In this work, simultaneous measurements of size and velocity of particles emitted by humans while speaking have been performed by means of Interferometric Laser Imaging Droplet Sizing (ILIDS). This technique allowed us to detect emitted particles with size down to 2 µm as well as to quantify all three components of the velocity vector and the particle concentration. The outcomes of this work may be used as boundary conditions for numerical simulations of infected respiratory cloud transmission.
Graphical abstract
Abstract
OBJECTIVES
The prognostic role of the number of resected and metastatic lymph nodes in non-small-cell lung cancer (NSCLC) is still being debated. The aim of this study was to evaluate the ...impact of lymphadenectomy in addition to the already validated variables in NSCLC survival.
METHODS
From January 2002 to December 2012, data on 4858 patients with NSCLC undergoing anatomical lung resection and hilomediastinal lymphadenectomy in 6 institutions were analysed retrospectively. Established prognostic factors in addition to the number of resected lymph nodes and the ratio between the number of metastatic lymph nodes and the number of resected lymph nodes (NR) were correlated to overall survival (OS) and disease-free survival (DFS) using the multivariable Cox regression model. Harrell’s C-statistic with the 95% confidence interval (CI) was determined. Analysis by means of maximally selected log-rank statistics was performed to find optimal cut-off points in order to split patients into groups with different outcome probabilities.
RESULTS
The median numbers of resected lymph nodes and of metastatic lymph nodes were 17 (range 6–85) and 2 (1–36), respectively. Hilar (N1) and mediastinal (N2) metastases were identified in 21.3% and 20.0% of cases, respectively. Overall, the 5-year OS and DFS rates were 54.6% and 44.8%, respectively. At multivariable analysis, age, gender, pathological stage, R0 resection, type of surgery and NR correlated with longer OS rates; the same variables plus tumour grading were further related to DFS. C-statistics were 66.0 (95% CI 62.7–69.4) for DFS and 60.5 (95% CI 58.3–62.6) for OS. An NR <40% significantly correlated with a higher 5-year survival rate in the total sample (OS 57.6% vs 23.8%, P < 0.001; DFS 48.2% vs 11.4, P < 0.001) and in patients with N1 (OS 47.9% vs 36.1%, P = 0.03; DFS 39% vs 24.2%, P = 0.02) and N2 (OS 36.9% vs 21.8%, P < 0.001 DFS 23.9% vs 9.1%, P < 0.001).
CONCLUSIONS
Our study confirms that the number of resected lymph nodes is a strong prognostic indicator in NSCLC. In particular, an NR cut-off value of 40% may predict both OS and DFS.
Abstract Objective This study investigated the prognostic impact of multimodality therapies in locally advanced thymomas. Methods From January 1990 to January 2010, clinicopathological, surgical, and ...oncological features were retrospectively reviewed in a cohort of 370 Masaoka-Koga stage III thymomas (World Health Organization classification A to B3) collected from 37 institutions. A multivariate Cox proportional hazard model was created to identify independent predictors of overall, cancer-specific (CSS), and relapse-free survivals. Furthermore, a propensity score–matching analysis for exposure to adjuvant (AT) therapy was generated. Results Induction therapy and AT were administered to 88 (24.9%) and 245 (69.4%) patients, respectively. Overall, 5- and 10-year overall survival, CSS, and relapse-free survivals were 82.8%, 88.4%, and 80.0%, and 68.9%, 83.3%, and 71.5%, respectively. At multivariable analysis performed in the matched cohort, AT was confirmed as the strongest predictive factor for overall survival (hazard ratio, 2.83; 95% confidence interval, 0.88-9.12; P = .08) and CSS (hazard ratio, 4.70; 95% confidence interval, 1.00-22.2; P = .05). Pathologic T classification (according to International Association for the Study of Lung Cancer and International Thymic Malignancy Interest Group TNM staging proposal) was an independent factor for relapse (hazard ratio, 8.69; 95% confidence interval, 1.08-70.04; P = .04). When CSS was adjusted for T classification, AT confirmed a significant survival advantage for pT3 tumors ( P = .04). On the other hand, for thymomas larger than 5 cm, stratifying for tumor size and AT did not affect 5-year CSS ( P = .17). Conclusions Our results indicate that AT is beneficial for locally advanced thymomas, mainly for specific pathologic features (pT3 or tumor size smaller than 5 cm). Further larger studies are needed to confirm these data.
Abstract
There is growing evidence that inflammatory, immunologic, and metabolic status is associated with cancer patients survival. Here, we built a simple algorithm to predict lung cancer outcome. ...Perioperative routine blood tests (RBT) of a cohort of patients with resectable primary lung cancer (LC) were analysed. Inflammatory, immunologic, and metabolic profiles were used to create a single algorithm (RBT index) predicting LC survival. A concurrent cohort of patients with resectable lung metastases (LM) was used to validate the RBT index. Charts of 2088 consecutive LC and 1129 LM patients undergoing lung resection were evaluated. Among RBT parameters, C-reactive protein (CRP), lymphocytes, neutrophils, hemoglobin, albumin and glycemia independently correlated with survival, and were used to build the RBT index. Patients with a high RBT index had a higher 5-year mortality than low RBT patients (adjusted HR 1.93, 95% CI 1.62–2.31). High RBT patients also showed a fourfold higher risk of 30-day postoperative mortality (2.3% vs. 0.5%, p 0.0019). The LM analysis validated the results of the LC cohort. We developed a simple and easily available multifunctional tool predicting short-term and long-term survival of curatively resected LC and LM. Prospective external validation of RBT index is warranted.
The prognostic role of baseline C-reactive protein (CRP) in chronic obstructive pulmonary disease (COPD) is controversial. In order to clarify this issue, we performed a systematic review and ...meta-analysis to assess the predictive effect of baseline CRP level in COPD patients. 15 eligible articles focusing on late mortality in COPD were included in our study. We performed a random-effects meta-analysis, and assessed heterogeneity and publication bias. We pooled hazard ratio (HR) estimates and their 95% confidence intervals on mortality for the comparison between the study-specific highest category of CRP level versus the lowest category. In overall analysis, elevated baseline CRP levels were significantly associated with higher mortality (HR 1.53, 95% CI 1.32-1.77, I
=68.7%, p<0.001). Similar results were observed across subgroups. However, higher mortality risk was reported in studies using a cut-off value of 3 mg·L
(HR 1.61, 95% CI 1.12-2.30) and in those enrolling an Asiatic population (HR 3.51, 95% CI 1.69-7.31). Our analysis indicates that baseline high CRP level is significantly associated with higher late mortality in patients with COPD. Further prospective controlled studies are needed to confirm these data.
A neutral boundary layer was generated in the laboratory to analyze the mean velocity field and the turbulence field within and above an array of two-dimensional obstacles simulating an urban canopy. ...Different geometrical configurations were considered in order to investigate the main characteristics of the flow as a function of the aspect ratio (
AR
) of the canopy. To this end, a summary of the two-dimensional fields of the fundamental turbulence parameters is given for
AR
ranging from 1 to 2. The results show that the flow field depends strongly on
AR
only within the canyon, while the outer flow seems to be less sensitive to this parameter. This is not true for the vertical momentum flux, which is one of the parameters most affected by
AR
, both within and outside the canyon. The experiments also indicate that, when
A
R
≲
1.5
(i.e. the skimming-flow regime), the roughness sub-layer extends up to a height equal to 1.25 times the height of the obstacles
(
H
)
, surmounted by an inertial sub-layer that extends up to
2.7
H
. In contrast, for
A
R
>
1.5
(i.e. the wake-interference regime) the inertial sub-layer is not present. This has significant implications when using similarity laws for deriving wind and turbulence profiles in canopy flows. Furthermore, two estimations of the viscous dissipation rate of turbulent kinetic energy of the flow are given. The first one is based on the fluctuating strain rate tensor, while the second is related to the mean strain rate tensor. It is shown that the two expressions give similar results, but the former is more complicated, suggesting that the latter might be used in numerical models with a certain degree of reliability. Finally, the data presented can also be used as a dataset for the validation of numerical models.
Abstract Background Higher blood levels of C-reactive protein (CRP) have been associated with shorter survival in patients with cardiovascular, chronic obstructive pulmonary disease and cancer. We ...investigated the impact of baseline and postoperative CRP levels on survival of patients with operable lung cancer (LC). Patients and methods CRP values at baseline (CRP0 ) and 3 days after surgery (CRP3 ) were measured in a consecutive series of 1750 LC patients who underwent complete resection between 2003 and 2015. Patients were classified as having 0 ( N = 593), 1 ( N = 658) or 2 ( N = 553) risk factors: CRP0 and/or CRP3 values above the respective median value. The effect of higher CRP was evaluated by Kaplan–Meier mortality curves and adjusted hazard ratio (HR) with 95% confidence interval (CI), by fitting Cox proportional hazards models. Results Cumulative proportions of 5-year survival were 67% for 0 risk factors, 58% for 1 risk factor and 41% for 2 risk factors ( P < 0.0001). The overall 5-year mortality risk was significantly higher in patients with 1 risk factor (adjusted hazard ratio aHR 1.43 95% CI 1.14–1.79), or 2 risk factors (aHR 2.49 95% CI 1.99–3.11). A significant impact on survival was observed in each tumour-node-metastasis stage group, and in the subset of non-smokers. Postoperative 30-day mortality was significantly higher in patients with 2 risk factors only (aHR 2.2% versus 0.6%, p < 0.0475). Conclusions Baseline and postoperative CRP levels predict immediate and long-term mortality in all stages of operable lung cancer. Patients with higher CRP levels could be candidate to randomised adjuvant trials with anti-inflammatory agents.
Lagrangian and Eulerian statistics are obtained from a water-channel experiment of an idealized two-dimensional urban canopy flow in neutral conditions. The objective is to quantify the Eulerian
(
T
...E
)
and Lagrangian
(
T
L
)
time scales of the turbulence above the canopy layer as well as to investigate their dependence on the aspect ratio of the canopy,
AR
, as the latter is the ratio of the width (
W
) to the height (
H
) of the canyon. Experiments are also conducted for the case of flat terrain, which can be thought of as equivalent to a classical one-directional shear flow. The values found for the Eulerian time scales on flat terrain are in agreement with previous numerical results found in the literature. It is found that both the streamwise and vertical components of the Lagrangian time scale,
T
u
L
and
T
w
L
, follow Raupach’s linear law within the constant-flux layer. The same holds true for
T
w
L
in both the canopies analyzed
(
A
R
=
1
and
A
R
=
2
) and also for
T
u
L
when
A
R
=
1
. In contrast, for
A
R
=
2
,
T
u
L
follows Raupach’s law only above
z
=
2
H
. Below that level,
T
u
L
is nearly constant with height, showing at
z
=
H
a value approximately one order of magnitude greater than that found for
A
R
=
1
. It is shown that the assumption usually adopted for flat terrain, that
β
=
T
L
/
T
E
is proportional to the inverse of the turbulence intensity, also holds true even for the canopy flow in the constant-flux layer. In particular,
γ
/
i
u
fits well
β
u
=
T
u
L
/
T
u
E
in both the configurations by choosing
γ
to be 0.35 (here,
i
u
=
σ
u
/
u
¯
, where
u
¯
and
σ
u
are the mean and the root-mean-square of the streamwise velocity component, respectively). On the other hand,
β
w
=
T
w
L
/
T
w
E
follows approximately
γ
/
i
w
=
0.65
/
σ
w
/
u
¯
for
z
>
2
H
, irrespective of the
AR
value. The second main objective is to estimate other parameters of interest in dispersion studies, such as the eddy diffusivity of momentum
(
K
T
)
and the Kolmogorov constant
(
C
0
)
. It is found that
C
0
depends appreciably on the velocity component both for the flat terrain and canopy flow, even though for the latter case it is insensitive to
AR
values. In all the three experimental configurations analyzed here,
K
T
shows an overall linear growth with height in agreement with the linear trend predicted by Prandtl’s theory.
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