Combined Technique Approach Research Articles

Controls of Mineral Solubility on Adsorption-Induced Molecular Fractionation of Dissolved Organic Matter Revealed by 21 T FT-ICR MS.

Mineral adsorption-induced molecular fractionation of dissolved organic matter (DOM) affects the composition of both DOM and OM adsorbed and thus stabilized by minerals. However, it remains unclear what mineral properties control the magnitude of DOM fractionation. Using a combined technique approach that leverages the molecular composition identified by ultrahigh resolution 21 T Fourier transform ion cyclotron resonance mass spectrometry and adsorption isotherms, we catalogue the compositional differences that occur at the molecular level that results in fractionation due to adsorption of Suwannee River fulvic acid on aluminum (Al) and iron (Fe) oxides and a phyllosilicate (allophane) species of contrasting properties. The minerals of high solubility (i.e., amorphous Al oxide, boehmite, and allophane) exhibited much stronger DOM fractionation capabilities than the minerals of low solubility (i.e., gibbsite and Fe oxides). Specifically, the former released Al3+ to solution (0.05-0.35 mM) that formed complexes with OM and likely reduced the surface hydrophobicity of the mineral-OM assemblage, thus increasing the preference for adsorbing polar DOM molecules. The impacts of mineral solubility are exacerbated by the fact that interactions with DOM also enhance metal release from minerals. For sparsely soluble minerals, the mineral surface hydrophobicity, instead of solubility, appeared to be the primary control of their DOM fractionation power. Other chemical properties seemed less directly relevant than surface hydrophobicity and solubility in fractionating DOM.

Applications of remote sensing and near-surface geophysical methods for the investigations of a morainic ridge susceptible to landslide. A case study from the high lands of the Himalayas, Pakistan

Numerous factors are necessary to comprehensively comprehend the complex phenomenon of landslides and, ultimately, facilitate effective measures for their protection and management. This paper investigates the case history of the Maicher landslide in the Nagar District (Northern Pakistan) by using a multidisciplinary combined technique approach based on conventional geophysical measurements and modern remote sensing techniques. The first technique is to identify the rate of deformations with real-time landslide monitoring sensors and satellite images. Care is devoted to data acquisition and processing using the ad-hoc methodology to minimize errors and ensure high reliability. For the second technique (electrical resistivity tomography, surface waves measurements, and ground-penetrating radar), convenient methods for landslide characterization are used and herein presented. The combination of information taken from the different techniques allows the results to be validated by conventional and modern approaches and enhances the accuracy of each method. The results suggest that shear surface planes at a depth of 35–40 m have developed over time. The analysis also provided information on controlling factors and possible expansion of the different slope sections. This work highlighted that geophysical parameters (shear wave velocity Vs, dielectric constant ε, and resistivity value ρ) could provide reliable qualitative and quantitative information about the shallow layer, bedrock contacts, possible sliding surface and subsurface water saturation, and seepage system of a landslide. The geophysical results reflect an overview of the geological model and are effective in terms of the slope stabilization process.

Expanding the Analytical Window for Biochar Speciation: Molecular Comparison of Solvent Extraction and Water-Soluble Fractions of Biochar by FT-ICR Mass Spectrometry.

Biochar, a low-density yet carbon-rich material derived from different organic materials pyrolyzed under low or no oxygen conditions, has been widely studied as a soil amendment, for greenhouse gas mitigation and in remediation of trace element-contaminated soils. Molecular speciation of biochar compounds has been challenging due to low solubility, aggregation, and immense compositional polydispersity that challenges nearly all mass spectrometry methods routinely applied to carbon-based organic materials. Through a combined technique approach that applies advanced analytical strategies, we provide bulk and molecular characterization of Kentucky bluegrass biochar that can be applied to any biomass or biochar sample. First, we characterize Kentucky bluegrass biochar chemical functional groups by solid-state magic-angle spinning dynamic nuclear polarization NMR (MAS-DNP NMR) and resolve aromatic and aliphatic signals from the pyrogenic material and intact plant material. Next, we isolate water-soluble biochar species by solid-phase extraction followed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and identify highly polar, oxygen species across a wide carbon number range. Solvent fractionation of biochar further expands the compositional range and identifies condensed polycyclic aromatic species across nonpolar and polar classes detected by two ionization modes (-ESI and +APPI) by FT-ICR MS. Plotting biochar species with DBE versus carbon number highlights the pericondensed molecular structural motif that persists across numerous heteroatom classes and ionization modes. To the best of our knowledge, this is the first molecular level identification of nonfunctionalized PAHs in biochar extracts by APPI FT-ICR MS. Thus, we identify biochar species that span the same compositional space as coal, heavy oil asphaltenes, and coal tar and correspond to condensed ring PAHs.

Monitoring and quantifying morphological and structural changes in electrode materials under operando conditions

X-ray absorption and small-angle x-ray scattering spectra were simultaneously acquired under operando conditions in a joined technique approach, for the first time applied in the field of energy storage materials. This approach allows one to closely follow the electronic and local structure evolution, as well as monitor and quantify the morphological and nanostructural changes occurring during electrochemical cycling. Here we demonstrate its potential on the example of doped and non-doped Fe2O3 anode material vs. Li. Our results reveal that upon discharge Fe3+ is gradually reduced to the metallic state and segregated as nanoparticles. For the relithiation reaction, upon subsequent charge, we observe improved reversibility for the Sr-doped compared to non-doped and Ca-doped Fe2O3. We highlight that this combined technique approach is a reliable, facile and powerful tool to investigate electrode materials under realistic cycling condition. It provides an unbiased and holistic picture of the morphological and structural changes occurring during operation, which allows for adequate material tailoring.

Complex anal fistulae management by combined technique approach: an experience

Background: The aim of this study is to evaluate our experience in the management of complex anal fistulae by combined technique approach. Ideal surgical treatment for complex anal fistula should aim to eradicate the source of infection and promote healing of the tract, while preserving the sphincters and the mechanism of anal continence. Even with the evolving newer techniques complex anal fistulae have higher rates of recurrence and functional disability as anal incontinence. The requirement of multiple surgeries for recurrence and the newer techniques like anal fistula plug are expensive and will become a burden for patients living in developing countries like ours. Thus, apart from Ligation of Intersphincteric fistula tract, the use of cutting seton is the main surgical method practiced here. This article focuses on the approach to the complex anal fistula management through evidence-based treatment strategies.Methods: Author conducted a prospective study of 35 complex anal fistulae patients undergoing combined technique approach with cutting Seton, Ligation of Intersphincteric Fistula tract and fistulotomy. Results: All patients recovered well with no complications in postoperative period. After 2 years of follow up patients are recurrence free and only 2 patients had partial incontinence with improving trend.Conclusions: The use of cutting Seton in high anal fistula is an effective technique. LIFT technique is good for Transphincteric tracts without previous scarring; it can be easily learned and applied. We can conclude that combined technique was an effective procedure and valid alternative for complex anal fistula management.

Detailed Compositional Characterization of the 2014 Bangladesh Furnace Oil Released into the World’s Largest Mangrove Forest

On December 9, 2014, ∼94 000 gallons of furnace oil spilled into the Shela River in Bangladesh, a designated World Heritage Site by the United Nations Educational, Scientific and Cultural Organization. It was the largest recorded oil spill in the Sundarbans region. Visually, furnace oil appears similar to heavy fuel oil, but little is known about its composition even though it is heavily utilized worldwide. A shift in global oil production to heavier, less well-known feeds (i.e., heavy oil and bitumen) requires molecular-level knowledge for efficient response, damage assessment, and restoration in the event of any oil spill. However, little is known about the chemical composition of furnace oil in chronic and acute releases. For the first time, we catalog the molecular-level composition of a relatively unknown furnace oil collected immediately after the 2014 Bangladesh spill and compare it to a well-characterized intermediate fuel oil (IFO) spilled in Texas City, Texas (U.S.A.) in March 2014. Through a combined technique approach, we apply comprehensive two-dimensional gas chromatography (GC×GC) analysis and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to contrast the unknown furnace oil to IFO. Combined, these techniques capture the continuum of oil components and access the less volatile, highly complex non-GC amenable compounds. GC×GC analysis provides biomarker signatures that suggest the furnace oil likely originated in the Middle East and is a refined product. We further compared the furnace oil with the Arabian light crude from Middle East origin (WP681) and revealed remarkable similarities between the two oils. Simulated distillation for the furnace oil showed that 42% of the oil mass is not volatile below 478 °C (equivalent to C40; the upper limit for GC-based techniques), whereas the IFO contained 38% of the total mass >C40. Furthermore, FT-ICR MS extends the carbon number range and unlocks the molecular composition of non-GC amenable compounds. Atmospheric pressure photoionization (APPI) and electrospray ionization (ESI) FT-ICR MS resolve and identify tens of thousands of molecular formulas in each oil and report furnace oil composition similar to whole heavy crudes. To the best of our knowledge, this is the first report of the detailed compositional characterization of any furnace oil.

Mapping Coral Reef Habitats in Southeast Florida Using a Combined Technique Approach

To create maps of nearshore benthic habitats of Broward County, Florida, from 0 to 35 m depth, we combined laser bathymetry, acoustic ground discrimination, subbottom profiling, and aerial photography data in a geographic information system (GIS). A mosaic of interpolated, sun-shaded, laser bathymetry data served as the foundation upon which acoustic ground discrimination, limited subbottom profiling and aerial photography, and groundtruthing data aided in interpretation of habitats. Mapping criteria similar to NOAA biogeographic Caribbean mapping were used to allow for a comparable output. Expert-driven visual interpretation outlined geomorphological features at a scale of 1 : 6000 with a minimum mapping unit of 1 acre. Acoustic data were then used to differentiate areas of similar geomorphology by their acoustic diversity into areas of high and low scatter, which could be equated to rugosity created by either the substratum or benthic fauna. Of the approximately 112 km2 mapped, 56.62 km2 were coral reef and colonized hard bottom (50.42%), 54.78 km2 were unconsolidated sediments (46.80%), and 0.43 km2 were other categories (2.78%). Three linear reef complexes exist. The outermost linear reef has a mature windward reef morphology including a drowned spur and groove system, which was absent on the other two reef lines. The acoustic ground discrimination and groundtruthing showed different benthic habitats on the outer vs. middle and inner reefs. Higher acoustic scatter could be related to taller benthos and more rugose substratum. A considerable amount of colonized pavement (nearshore hard grounds) was found inshore. The map of Broward County yielded a high overall accuracy of 89.6%, only slightly less than the photo-interpreted NOAA Caribbean maps (overall accuracy of 91.1%). User and producer accuracies within each category were also similar. The combined technique approach was effective and accurate, and similar methodology can be used in other areas where photo interpretation is not feasible because of turbidity or depth limitations.

Preoperative high-dose leucovorin/5-fluorouracil and radiation therapy for unresectable rectal cancer

Twenty patients with primary or recurrent unresectable rectal cancer limited to the pelvis were entered on a Phase I trial of preoperative pelvic radiation therapy (RT) (5040 cGy) and two cycles of combined high-dose leucovorin (LV) and 5-fluorouracil (5-FU), followed by surgery and ten cycles of postoperative LV/5-FU (sequential). Maximum tolerated doses (MTD) were determined for preoperative combined LV/5-FU and RT and for postoperative sequential LV/5-FU. 5-FU was escalated 50 mg/m2 while the LV remained constant at 200 mg/m2. The initial doses of 5-FU were combined LV/5-FU and RT (200 mg/m2) and sequential LV/5-FU (325 mg/m2). The median follow-up time was 14 months. The resectability rate was 89%, and the pathologic complete response rate was 21%. The MTD for combined LV/5-FU and RT was 300 mg/m2; therefore, the recommended dose of 5-FU is 250 mg/m2. The recommended dose of 5-FU for sequential LV/5-FU is 375 mg/m2. The dose-limiting toxicities in this trial were diarrhea, tenesmus, increased bowel movements, dysuria, and myelosuppression. For the six patients who received 5-FU at the recommended dose level, the median low counts were leukocyte count, 3.7/microliters (range, 2.4 to 4.9/microliters); hemoglobin, 9.0 g/dl (range, 8.2 to 11.9 g/dl); and platelet count (X1000), 146/microliters (range, 89 to 182/microliters). The incidence rate of any Grade 3 toxicity was 17% (diarrhea and frequent bowel movements). The recommended doses of 5-FU used in this protocol were well tolerated. Because there was a long delay before optimal doses of 5-FU could be delivered, the authors do not recommend that high-dose LV be used in conjunction with combined 5-FU and RT with the treatment regimen as currently designed. However, because the resectability and complete response rates were higher than those previously reported for preoperative RT alone, the authors are encouraged by the combined technique approach. New trials are currently being undertaken to determine if the use of a low-dose LV regimen is more tolerable.

Combined use of mask CPAP and minitracheotomy as an alternative to endotracheal intubation

We describe the combined use of mask CPAP (continuous positive airway pressure) and minitracheotomy as an alternative to conventional endotracheal intubation in 3 patients requiring CPAP, secretion removal and diagnostic procedures such as bronchoalveolar lavage and bronchial cultures. These requirements were fulfilled with the combined technique approach, thus preserving glottic function and avoiding the disadvantages of endotracheal intubation of tracheotomy. This approach seems particularly suitable in the treatment of immunocompromised patients because of its reduced invasiveness.