262 research outputs found
Critical issues in ionospheric data quality and implications for scientific studies
Ionospheric data are valuable records of the behavior of the ionosphere, solar activity, and the entire Sun-Earth system. The data are critical for both societally important services and scientific investigations of upper atmospheric variability. This work investigates some of the difficulties and pitfalls in maintaining long-term records of geophysical measurements. This investigation focuses on the ionospheric parameters contained in the historical data sets within the National Oceanic and Atmospheric Administration National Geophysical Data Center and Space Physics Interactive Data Resource databases. These archives include data from approximately 100 ionosonde stations worldwide, beginning in the early 1940s. Our study focuses on the quality and consistency of ionosonde data accessible via the primary Space Physics Interactive Data Resource node located within the National Oceanic and Atmospheric Administration National Geophysical Data Center and the World Data Center for Solar-Terrestrial Physics located in Boulder, Colorado. We find that, although the Space Physics Interactive Data Resource archives contained an impressive amount of high-quality data, specific problems existed involving missing and noncontiguous data sets, long-term variations or changes in methodologies and analysis procedures used, and incomplete documentation. The important lessons learned from this investigation are that the data incorporated into an archive must have clear traceability back to the primary source, including scientific validation by the contributors, and that the historical records must have associated metadata that describe relevant nuances in the observations. Although this report only focuses on historical ionosonde data in National Oceanic and Atmospheric Administration databases, we feel that these findings have general applicability to environmental scientists interested in using long-term geophysical data sets for climate and global change research.Peer ReviewedPostprint (published version
Quantitative kinetics and enthalpy measurements of biphasic underflow chemical reactions by InfraRed Thermography
Abstract The scope of this paper is to present the experimental study of a well known chemical reaction in a biphasic millifluidic droplet flow by using InfraRed Thermography. This simple thermal evaluation enables the characterization of kinetics and enthalpy of exothermic chemical reactions. The originality of this work is the application of a very simple thermal model based on an homogenized thin body approximation to perform calorimetric estimations. This novel calorimeter needs a thermal calibration step to estimate the heat losses (W). Then, a correlation method is applied for the simultaneous estimation of the heat source (φ) and the characteristic coefficient due the convective effects (H). Here the estimation of the characteristic coefficient H (s −1 ) is done at each flow rate ratio (R). This procedure is applied for several chemical reaction performed at different flow rate ratios. Then, the enthalpy is estimated with an error lower than 2%. In addition, the methodology to estimate the mixing kinetics of the reaction can be pointed out by the integrated flux over the time. Finally, a non contact thermal calorimeter based on millifluidic and IR thermography was developed. It is a convenient and powerful tool for the characterization of chemical reaction performed in a droplet flow
Microscale spectroscopic thermal imaging of n-alkanes
Abstract Based on the recent development of our team on simultaneous measurement of thermal and spectral IR images, in this paper, the study of phase transition of molecular organic crystals, n-Tetraosane (C24H50), as a typical n-alkane will be presented. The goal is to demonstrate the high potentiality of the device in the study of couple phenomena
Mid-infrared spectroscopic thermotransmittance measurements in dielectric materials for thermal imaging
Thermal considerations affect the performance of most microsystems. Although surface techniques can give information on the thermal properties within the material or about buried heat sources and defects, mapping temperature and thermal properties in three dimension (3D) is critical and has not been addressed yet. Infrared thermography, commonly used for opaque materials, is not adapted to semi-transparent samples such as microfluidic chips or semiconductor materials in the infrared range. This work aims at answering these needs by using the variations of transmittance with temperature to obtain information on the temperature within the thickness of the sample. We use a tunable mid-infrared light source combined with an infrared camera to measure these variations of transmittance in a glass wafer. We couple this technique with a thermal model to extract the thermotransmittance coefficient—the coefficient of temperature variation of the transmittance. We then introduce a semiempirical model based on Lorentz oscillators to estimate the temperature-dependent optical properties of our sample in the mid-IR spectral range. Combined with the measurement, this paper reports the spectroscopic behavior of the thermotransmittance coefficient in the mid-IR range and a way to predict it
Long-term field metal extraction by pelargonium:phytoextraction efficiency in relation to plant maturity
The long length of periods required for effective soil remediation via phytoextraction constitutes a weak point that reduces its industrial use. However, these calculated periods are mainly based on short-term and/or hydroponic controlled experiments. Moreover, only a few studies concern more than one metal, although soils are scarcely polluted by only one element.In this scientific context, the phytoextraction of metals and metalloids (Pb, Cd, Zn, Cu,and As) by Pelargonium was measured after a long-term field experiment. Both bulk and rhizosphere soils were analyzed in order to determine the mechanisms involved in soil-root transfer. First, a strong increase in lead phytoextraction was observed with plant maturity, significantly reducing the length of the period required for remediation. Rhizosphere Pb, Zn, Cu, Cd, and As accumulation was observed (compared to bulk soil), indicating metal mobilization by the plant, perhaps in relation to root activity. Moreover, metal phytoextraction and translocation were found to be a function of the metals’ nature. These results, taken altogether, suggest that Pelargonium could be used as a multi-metal hyperaccumulator under multi-metal soil contamination conditions, and they also provide an interesting insight for improving field phytoextraction remediation in terms of the length of time required, promoting this biological technique
Catalog of prognostic tissue-based biomarkers in patients treated with neoadjuvant systemic therapy for urothelial carcinoma of the bladder: a systematic review
PURPOSE
The present systematic review aimed to identify prognostic values of tissue-based biomarkers in patients treated with neoadjuvant systemic therapy (NAST), including chemotherapy (NAC) and checkpoint inhibitors (NAI) for urothelial carcinoma of the bladder (UCB).
MATERIAL AND METHODS
The PubMed, Web of Science, and Scopus databases were searched in August 2020 according to the PRISMA statement. Studies were deemed eligible if they compared oncologic or pathologic outcomes in patients treated with NAST for UCB with and without detected pretreatment tissue-based biomarkers.
RESULTS
Overall, 44 studies met our eligibility criteria. Twenty-three studies used immunohistochemistry (IHC), 19 – gene expression analysis, three - quantitative polymerase chain reaction (QT PCR), and two – next-generation sequencing (NGS). According to the currently available literature, predictive IHC-assessed biomarkers, such as receptor tyrosine kinases and DNA repair pathway alterations, do not seem to convincingly improve our prediction of pathologic response and oncologic outcomes after NAC. Luminal and basal tumor subtypes based on gene expression analysis showed better NAC response, while claudin-low and luminal-infiltrated tumor subtypes did not. In terms of NAI, PD-L1 seems to maintain value as a predictive biomarker, while the utility of both tumor mutational burden and molecular subtypes remains controversial. Specific genomic alterations in DNA repair genes have been shown to provide significant predictive value in patient treated with NAC. QT PCR quantification of specific genes selected through microarray analysis seems to classify cases regarding their NAC response.
CONCLUSION
We believe that the present systematic review may offer a robust framework that will enable the testing and validation of predictive biomarkers in future prospective clinical trials. NGS has expanded the discovery of molecular markers that are reflective of the mechanisms of the NAST response
Benefit and Harm of Active Surveillance for Biopsy-proven Renal Oncocytoma : A Systematic Review and Pooled Analysis
Context: Active surveillance (AS) of biopsy-proven renal oncocytomas may reduce overtreatment. However, on biopsy, the risk of misdiagnosis owing principally to entities with peculiar hybrids and overlap morphology, and phenotypes argues for early intervention. Objective: To assess the benefit and harm of AS in biopsy-proven renal oncocytoma. Evidence acquisition: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). We systematically searched PubMed, Scopus, and Web of Science databases from September 26 up to October 2021, for studies that analyzed the outcomes of AS in patients with biopsy-proven renal oncocytoma. Evidence synthesis: A total of ten studies with 633 patients met our inclusion criteria and were included for analysis. After a median follow-up of 34.5 mo (95% confidence interval [CI] 30.6-38.4), the overall definitive treatment rate from AS to definitive treatment was 17.3% (n = 75/433, six studies). The pooled pathological agreement between the initial renal mass biopsy and the surgical pathology report was 91.1%. The main indications for surgery during follow-up were rapid tumor growth and patient request. The pooled median growth rate was 1.55 mm/yr (95% CI 0.9-2.2). No metastasis or death related to renal oncocytoma was reported. Conclusions: Annual tumor growth of biopsy-proven renal oncocytoma is low. AS is oncologically safe, with favorable compliance of patients. Crossover to definitive treatment revealed a strong concordance between biopsy and final pathology. Further studies on the long-term outcomes of AS are needed. Patient summary: In this study, we examined the benefit and harm of active surveillance (AS) in biopsy-proven oncocytoma. Based on the available data, AS appears oncologically safe and may represent a promising alternative to immediate treatment. Patients should be included in AS decision discussions
Intravesical Therapy in Patients with Intermediate-risk Non–muscle-invasive Bladder Cancer: A Systematic Review and Network Meta-analysis of Disease Recurrence
Context
Patients with intermediate-risk non–muscle-invasive bladder cancer (NMIBC) may pose a clinical dilemma without an agreed evidence-based decision tree for personalized treatment. Objective
To perform a systematic review and network meta-analysis (NMA) to summarize available evidence on the oncologic outcomes of intravesical therapy in patients with intermediate-risk NMIBC.
Evidence acquisition
The MEDLINE, EMBASE, and ClinicalTrials.gov databases were searched in October 2020 according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. Studies were deemed eligible if they reported on oncologic outcomes in patients with intermediate-risk NMIBC treated with transurethral resection of bladder tumor with and without intravesical chemotherapy or bacillus Calmette-Guérin (BCG) immunotherapy. Evidence synthesis
Twelve studies were included in a qualitative synthesis (systematic review); three were deemed eligible for a quantitative synthesis (NMA). An NMA of five different regimens was conducted for the association of treatment with the 5-yr recurrence risk. Chemotherapy with maintenance was associated with a lower likelihood of 5-yr recurrence than chemotherapy without maintenance (odds ratio [OR] 0.51, 95% credible interval [CI] 0.26–1.03). Immunotherapy, regardless of whether a full- or reduced-dose regimen, was not associated with a significantly lower likelihood of 5-yr recurrence when compared with chemotherapy without maintenance (OR 0.90, 95% CI 0.39–2.11 vs OR 0.93, 95% CI 0.40–2.19). Analysis of the treatment ranking revealed that chemotherapy with maintenance had the lowest 5-yr recurrence risk (P score 0.9666).
Conclusions
Our analysis indicates that chemotherapy with a maintenance regimen confers a superior oncologic benefit in terms of 5-yr recurrence risk compared to chemotherapy without maintenance in patients with intermediate-risk NMIBC. Regardless of the dose regimen, immunotherapy with BCG does not appear to be superior to chemotherapy in patients with intermediate-risk NMIBC in term of disease recurrence. However, owing to the lack of comparative studies, there is an unmet need for well-designed, large-scale trials to validate our findings and generate robust evidence on disease recurrence and progression. Patient summary
A maintenance schedule of chemotherapy reduces the rate of long-term recurrence of bladder cancer that has not invaded the bladder muscle. Chemotherapy inserted directly into the bladder and immunotherapy without maintenance schedules seem to have limited benefit in preventing cancer recurrence
The Efficacy and Safety of Metastasis-directed Therapy in Patients with Prostate Cancer:A Systematic Review and Meta-analysis of Prospective Studies
CONTEXT: Despite the lack of level 1 evidence, metastasis-directed therapy (MDT) is used widely in the management of metastatic prostate cancer (mPCa) patients. Data are continuously emerging from well-designed prospective studies.OBJECTIVE: To summarise and report the evidence on oncological and safety outcomes of MDT in the management of mPCa patients.EVIDENCE ACQUISITION: We searched the PubMed, Scopus, and Web of Science databases for prospective studies assessing progression-free survival (PFS), local control (LC), androgen deprivation therapy (ADT)-free survival (ADT-FS), overall survival (OS), and/or adverse events (AEs) in mPCa patients treated with MDT. A meta-analysis was performed for 1- and 2-yr PFS, LC, ADT-FS, OS, and rate of AEs. Meta-regression and sensitivity analysis were performed to account for heterogeneity and identify moderators.EVIDENCE SYNTHESIS: We identified 22 prospective studies (n = 1137), including two randomised controlled trials (n = 116). Two studies were excluded from the meta-analysis (n = 120). The estimated 2-yr PFS was 46% (95% confidence interval [CI]: 36-56%) or 42% (95% CI: 33-52%) after excluding studies using biochemical or ADT-related endpoints. The estimated 2-yr LC, ADT-FS, and OS were 97% (95% CI: 94-98%), 55% (95% CI: 44-65%), and 97% (95% CI: 95-98%), respectively. Rates of treatment-related grade 2 and ≥3 AEs were 2.4% (95% CI: 0.2-7%) and 0.3% (95% CI: 0-1%), respectively.CONCLUSIONS: MDT is a promising treatment strategy associated with favourable PFS, excellent LC, and a low toxicity profile that allows oligorecurrent hormone-sensitive patients to avoid or defer ADT-related toxicity. Integration of MDT with other therapies offers a promising research direction, in particular, in conjunction with systemic treatments and as a component of definitive care for oligometastatic PCa. However, in the absence of randomised trials, using MDT for treatment intensification remains an experimental approach, and the impact on OS is uncertain.PATIENT SUMMARY: Direct treatment of metastases is a promising option for selected prostate cancer patients. It can delay hormone therapy and is being investigated as a way of intensifying treatment at the expense of manageable toxicity.</p
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