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Stability of coprecipitated natural humic acid and ferrous iron under oxidative conditions
Colombo, C.,Palumbo, G.,Sellitto, V.M.,Cho, H.G.,Amalfitano, C.,Adamo, P. Elsevier 2015 Journal of geochemical exploration Vol.151 No.-
Goethite and lepidocrocite are considered the stable species of Fe oxyhydroxides formed from Fe<SUP>2+</SUP> oxidation in mildly acidic soil environments, while maghemite is formed in mildly alkaline conditions. Complexing ligands, especially humic acid (HA), can change the pathway formation of these iron oxyhydroxides from Fe<SUP>2+</SUP> oxidation. This research aimed to assess the influence of HA on Fe<SUP>2+</SUP> oxidation and its effect on crystalline Fe mineral products. Ferrous iron was added to HA at increasing initial COOH/Fe(II) charge ratios ® at pHs of 5.0 and 8.0 and aged at 70<SUP>o</SUP>C for 1month and up to 8years at room temperature. The precipitated products after aging were analysed using XRD, FT-IR, TEM and AFM. The results indicate that oxidation of Fe<SUP>2+</SUP> at pH5.0, in the presence of large amounts of HA (R=0.1) promoted the formation of goethite together with ferrihydrite. Oxidation of Fe<SUP>2+</SUP> in slightly alkaline conditions (pH8.0) yielded maghemite with small amounts of goethite. Further, long-term aging of HA coprecipitated with Fe<SUP>2+</SUP> perturbed the stacking of the Fe hydroxyl sheets at pH5.0, favouring the formation of ferrihydrite. At pH8.0 the presence of humic acid does not influence the crystallinity of the precipitation products and maghemite was still stable after 8years of aging. This research confirms that the oxidation of Fe<SUP>2+</SUP> in soil and its subsequent hydrolysis is a very common process of Fe hydroxides/oxide formation in acidic soil environments. The type of Fe oxide formed depends strictly on the pH and secondly on the rate of oxidation, especially on the presence and amount of organic compounds that inhibit crystal growth. Humic acid are the main organic molecules in soils, particularly in cool, humid weathering environments where they lead to a decrease in crystalline perfection and promote the formation of ferrihydrite instead of goethite or lepidocrocite. These results provide significant insights into the effect of the mobility of HA in association with Fe minerals.
Existing concrete dams: loads definition and finite element models validation
Colombo, Martina,Domaneschi, Marco,Ghisi, Aldo Techno-Press 2016 Structural monitoring and maintenance Vol.3 No.2
We present a methodology to validate with monitoring data finite element models of existing concrete dams: numerical analyses are performed to assess the structural response under the effects of seasonal loading conditions, represented by hydrostatic pressure on the upstream-downstream dam surfaces and thermal variations as recorded by a thermometers network. We show that the stiffness effect of the rock foundation and the surface degradation of concrete due to aging are crucial aspects to be accounted for a correct interpretation of the real behavior. This work summarizes some general procedures developed by this research group at Politecnico di Milano on traditional static monitoring systems and two significant case studies: a buttress gravity and an arch-gravity dam.
Alfredo Colombo,Concetta Maria Porretto 소화기인터벤션의학회 2024 International journal of gastrointestinal interven Vol.13 No.1
Colorectal cancer (CRC) is one of the most prevalent malignancies, and most patients are diagnosed with metastatic disease at first presentation. However, immunotherapy is particularly useful only in a limited number of patients with mismatch repair-deficient/high microsatellite instability metastatic CRC (mCRC), while most patients have proficient mismatch repair (pMMR)/microsatellite stability (MSS). Currently, many clinical research on immunotherapy in association with tyrosine kinase inhibitors are aiming to modulate the immune microenvironment of pMMR/MSS mCRC and turn “cold tumors” into “hot tumors,” which has not only unanticipated implications, but also good results. Some consequences include that the response may not be selective for metastases. This review summarizes recent studies on potential mechanisms of immunotherapy combined with local therapy (including radiotherapy, ablation, and transcatheter arterial chemoembolization) in the treatment of metastases.
Ultrafast imaging of soft materials during shear flow
Gabriele Colombo,Roberta Massaro,Steven Coleman,Jörg Läuger,Peter Van Puyvelde,Jan Vermant 한국유변학회 2019 Korea-Australia rheology journal Vol.31 No.4
The direct imaging of flow induced microstructural changes in complex fluids can have advantages over the use of scattering methods, since localized phenomena can be observed directly and more mechanistic insights can be obtained. This is useful in particular for materials with hierarchical or multiscale structures such as aggregated dispersions. Rheoconfocal instruments are ideally suited for this purpose but were, as yet, limited to relatively low imaging rates. In the present work, a stress-controlled rheometer was coupled to a fast scanning, instant structured illumination confocal microscope which uses a multi-array illumination and detection scheme. A second motor is integrated in a custom-made rheoconfocal instrument to achieve the counter-rotation of the lower glass plate. The resulting stagnation plane can be moved within the shearing gap in real time and allows the stable imaging of micro-structural features under steady shear. Velocity profiles were measured to validate the performance of the mechanical components, using particle image velocimetry on a sterically stabilized suspension. Structured illumination optics yielded an excellent inplane spatial resolution, while the multipoint scanning allows speeds as high as 1000 frames per second at full frame resolution. However, for rheological studies the 3D structure should ideally be resolved. The mechanical refocusing using a fast piezo stage at high speeds led to deformations of the lower thin glass plate. To circumvent this bottleneck, a focus-tunable lens was incorporated in the setup to acquire 3D image volumes at video rates. The excellent combination of temporal and spatial resolution under flow is demonstrated here using selected results from aggregated colloidal dispersions. The microstructure of a model depletion gel is studied over a broad range of shear rates under strong to moderate flow conditions. The ability to measure rheological properties while imaging the time-dependent microstructure is demonstrated with particles dispersed in a more viscous PDMS matrix. Transient rheology is reported simultaneously with high resolution imaging of the microscopic structural recovery. This novel tool enables the direct imaging of rheologically complex materials under conditions relevant to processing, to elucidate the physical phenomena underlying nonlinear rheology and thixotropy.
( Massimo Colombo ),( Alessio Aghemo ),( Lin Liu ),( Robert H. Hyland ),( Chohee Yun ),( Diana M. Brainard ),( John G. Mchutchison ),( Sunjin Hwang ),( Marc Bourliere ),( Markus Peck-radosavljevic ),( 대한간학회 2016 춘·추계 학술대회 (KASL) Vol.2016 No.1
Methods: Kidney transplant recipients with chronic GT1 or GT4 HCV infection, treatment-naive and treatment-experienced, with or without compensated cirrhosis were randomized 1:1 at 5 sites in Europe to receive LDV/SOF (90 mg/400 mg) for 12 or 24 weeks. Randomization was stratified by HCV genotype, treatment history and presence or absence of cirrhosis. Cirrhosis was determined by liver biopsy (Metavir score = 4 or Ishak score ≥5), Fibroscan® >12.5 kPa, or Fibrotest® >0.75 and APRI >2. A pretreatment creatinine clearance <40 mL/min was an exclusionary criterion. The primary endpoint was SVR12. Results: 114 patients were randomized and treated; median age was 53, 58% were male, 94% were white, 72% carried the non-CC IL28B allele, 91% had GT 1 infection, 69% were treatment-naive, and 15% had compensated cirrhosis. The median eGFR was 56ml/min (range 35-135ml/min). All 92 patients with SVR4 data available achieved SVR4 including a patient discontinuing treatment at Week 4 due to an AE. SAEs were reported in 12 (11%) patients; 3 were assessed as treatment related: syncope, pulmonary embolism, and blood creatinine increased. The most frequent AEs were headache (19%), asthenia (13%), and fatigue (10%). Conclusions: Administration of LDV/SOF for 12 or 24 weeks in patients with chronic HCV genotype 1 or 4 patients who have undergone kidney transplant was safe and highly effective with an SVR4 rate of 100%. Treatment was well-tolerated. SVR12 data for all patients will be presented.
Binoy C.,Delvare Gérard,Colombo Wesley D.,Surya K.S.,Sureshan P.M. 한국응용곤충학회 2023 Journal of Asia-Pacific Entomology Vol.26 No.4
Hymenopteran parasitoids of the black soldier fly (BSF) Hermetia illucens (Linnaeus, 1758) (Diptera, Strat iomyidae), are recorded from southern India. Two new species, Calyoza hermetiae Binoy, & Colombo sp. nov. (Bethylidae, Epyrinae) and Eniacomorpha bouceki Binoy sp. nov. (Chalcididae, Dirhininae) are described and illustrated. Spalangia cameroni Perkins, S. obscura Bouˇcek and S. simplex Perkins (Spalangiidae, Spalangiinae) and Dirhinus anthracia Walker (Chalcididae, Dirhininae) are also reported from BSF and are diagnosed and illustrated. A key to the hymenopteran parasitoids of BSF respectively belonging to Bethylidae (1 sp.), Chalcididae (4 spp.), Diapriidae (1 sp.), Spalangiidae (3 spp.), is provided. This study forms the first record of a host for Calyoza. Finally, the negative impact of these parasitoid assemblages on BSL is discussed.
Mismatched Imaging Findings of Prostate Cancer Diagnosis: 68 Ga-PSMA PET/CT vs mpMRI
Lopci Egesta,Colombo Piergiuseppe,Lazzeri Massimo 대한핵의학회 2021 핵의학 분자영상 Vol.55 No.4
Multiparametric magnetic resonance imaging (mpMRI) is the modality of choice for initial diagnosis of prostate cancer (PCa), including biopsy-naïve patients. Nevertheless, clinicians must be aware of the possibility that up to one-fourth of clinically significant cancers might be missed by the modality. Acknowledgment of this occurrence and the increased availability of 68 Ga-PSMA PET/CT in clinical routine, open the door to new, fascinating, indications for this functional modality in the context of PCa detection. With the case herein illustrated, we report a paradigmatic example of mismatch findings between PET/CT and mpMRI better elucidating the potential indication.