Identifying precursors and aqueous organic aerosol formation pathways during the SOAS campaign

Sareen, Neha,Carlton, Annmarie G.,Surratt, Jason D.,Gold, Avram,Lee, Ben,Lopez-Hilfiker, Felipe D.,Mohr, Claudia,Thornton, Joel A.,Zhang, Zhenfa,Lim, Yong B.,Turpin, Barbara J. Copernicus GmbH 2016 Atmospheric Chemistry and Physics Vol.16 No.22

<P>Abstract. Aqueous multiphase chemistry in the atmosphere can lead to rapid transformation of organic compounds, forming highly oxidized, low-volatility organic aerosol and, in some cases, light-absorbing (brown) carbon. Because liquid water is globally abundant, this chemistry could substantially impact climate, air quality, and health. Gas-phase precursors released from biogenic and anthropogenic sources are oxidized and fragmented, forming water-soluble gases that can undergo reactions in the aqueous phase (in clouds, fogs, and wet aerosols), leading to the formation of secondary organic aerosol (SOAAQ). Recent studies have highlighted the role of certain precursors like glyoxal, methylglyoxal, glycolaldehyde, acetic acid, acetone, and epoxides in the formation of SOAAQ. The goal of this work is to identify additional precursors and products that may be atmospherically important. In this study, ambient mixtures of water-soluble gases were scrubbed from the atmosphere into water at Brent, Alabama, during the 2013 Southern Oxidant and Aerosol Study (SOAS). Hydroxyl (OH⚫) radical oxidation experiments were conducted with the aqueous mixtures collected from SOAS to better understand the formation of SOA through gas-phase followed by aqueous-phase chemistry. Total aqueous-phase organic carbon concentrations for these mixtures ranged from 92 to 179 µM-C, relevant for cloud and fog waters. Aqueous OH-reactive compounds were primarily observed as odd ions in the positive ion mode by electrospray ionization mass spectrometry (ESI-MS). Ultra high-resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) spectra and tandem MS (MS-MS) fragmentation of these ions were consistent with the presence of carbonyls and tetrols. Products were observed in the negative ion mode and included pyruvate and oxalate, which were confirmed by ion chromatography. Pyruvate and oxalate have been found in the particle phase in many locations (as salts and complexes). Thus, formation of pyruvate/oxalate suggests the potential for aqueous processing of these ambient mixtures to form SOAAQ. </P>

Host-guest complexation behaviour of emissive calix[3]naphthobipyrrole toward aromatic guests

Sareen, Divya,Abebayehu, Abeje,Lee, Chang-Hee Informa UK (TaylorFrancis) 2018 Supramolecular chemistry Vol.30 No.11

Ion-mediated single-molecular optical switching and sensing based on the fluorophore-tethered calix[4]pyrrole

Sareen, Divya,Lee, Ji Hye,Hwang, Hyonseok,Yoo, Soeun,Lee, Chang-Hee The Royal Society of Chemistry 2016 Chemical communications Vol.52 No.34

<P>The design and synthesis of the first asymmetrically 'two-walled'' meso-substituted calix[4]pyrrole tethered by a fluorophore and its subsequent implication as an archetype sequential 'on-off-on-off' fluorescent single-molecular switch are reported. The current system permits us to extend the sensitivity up to sub-nanomolar levels with the detection limit as low as 0.4 nM.</P>

Total Cholesterol and Triglyceride Levels in Patients with Breast Cancer

Umesh Kapil,Ajeet Singh Bhadoria,Neha Sareen,Preeti Singh,Sada N. Dwivedi 한국유방암학회 2013 Journal of breast cancer Vol.16 No.1

Flipped Reposition Laminoplasty for Excision of Intradural Extramedullary Tumors in the Thoracolumbar Spine: A Case Series of 14 Patients

Ramesh Kumar,Ijack Debbarma,Tankeshwar Boruah,Atul Sareen,Mohit Kumar Patralekh,Ashish Dagar,Shaffaf Abdul Kareem 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.3

Study Design: A retrospective study was done to assess the outcome of the new technique of flipped reposition laminoplasty for excision of intradural extramedullary (IDEM) spinal tumors of the thoracolumbar region.Purpose: To describe flipped reposition laminoplasty technique and evaluate its outcomes. Overview of Literature: Laminectomy has been the conventional approach for the surgical excision of IDEM spinal tumors, but it has potential postoperative complications. Laminoplasty maintains the posterior arch of the spine and avoids complications seen in Laminectomy, such as instability, epidural scarring, and kyphotic deformity.Methods: Fourteen patients (nine females and five males) diagnosed with IDEM tumors of the thoracolumbar region operated between 2016 and 2018 were included in this study. Pathologically, five cases were schwannomas; four cases were meningiomas; two cases were ependymomas; and one case each was lymphoma, neurofibroma, and teratoma. All patients had their neurological deficits documented using the American Spinal Injury Association (ASIA) impairment scale. After completion of all preanesthetic formalities, the patients were operated upon by a single surgeon using the flipped reposition laminoplasty technique. Follow-up was done at 1, 3, 6, and 12 months post operation and yearly thereafter.Results: The mean age of the patients was 35.28 years (14–65 years), and the mean follow-up duration was 17 months (6–26 months). Two patients were assessed with ASIA grade A neurology, one patient improved to ASIA grade B, whereas the other did not improve. Two patients improved from ASIA grade B to ASIA grade D, and seven patients with ASIA grades C and D improved to ASIA grade E. Fusion at the osteotomy site was seen in 92.85% (13 out of 14) cases on one side within 6 months post operation. Fusion was seen in all the cases within 1 year post operation.Conclusions: Flipped reposition laminoplasty is an excellent technique providing adequate exposure and additional stability postoperatively.

Comparative evaluation of peri-implant stress distribution in implant protected occlusion and cuspally loaded occlusion on a 3 unit implant supported fixed partial denture: A 3D finite element analysis study

Paramba Hitendrabhai Acharya,Vilas Valjibhai Patel,Sareen Subhash Duseja,Vishal Rajendrabhai Chauhan 대한치과보철학회 2021 The Journal of Advanced Prosthodontics Vol.13 No.2

Purpose. To assess peri-implant stress distribution using finite element analysis in implant supported fixed partial denture with occlusal schemes of cuspally loaded occlusion and implant protected occlusion. Materials and methods. A 3-D finite element model of mandible with D2 bone with partially edentulism with unilateral distal extension was made. Two Ti alloy identical implants with 4.2 mm diameter and 10 mm length were placed in the mandibular second premolar and the mandibular second molar region and prosthesis was given with the mandibular first molar pontic. Vertical load of 100 N and and oblique load of 70 N was applied on occlusal surface of prosthesis. Group 1 was cuspally loaded occlusion with total 8 contact points and Group 2 was implant protected occlusion with 3 contact points. Results. In Group 1 for vertical load, maximum stress was generated over implant having 14.3552 Mpa. While for oblique load, overall stress generated was 28.0732 Mpa. In Group 2 for vertical load, maximum stress was generated over crown and overall stress was 16.7682 Mpa. But for oblique load, crown stress and overall stress was maximum 22.7561 Mpa. When Group 1 is compared to Group 2, harmful oblique load caused maximum overall stress 28.0732 Mpa in Group 1. Conclusion. In Group 1, vertical load generated high implant stress, and oblique load generated high overall stresses, cortical stresses and crown stresses compared to vertical load. In Group 2, oblique load generated more overall stresses, cortical stresses, and crown stresses compared to vertical load. Implant protected occlusion generated lesser harmful oblique implant, crown, bone and overall stresses compared to cuspally loaded occlusion.

Evaluation of calcium sulphate barrier to collagen membrane in intrabony defects

Shilpa Budhiraja,Neeta Bhavsar,Santosh Kumar,Khushboo Desai,Sareen Duseja 대한치주과학회 2012 Journal of Periodontal & Implant Science Vol.42 No.6

Purpose: The aim of this study was to clinically and radiographically evaluate and compare treatment of intrabony defects with the use of decalcified freeze-dried bone allograft in combination with a calcium sulphate barrier to collagen membrane. Methods: Twelve patients having chronic periodontal disease aged 20 to 50 years and with a probing depth >6 mm were selected. Classification of patient defects into experimental and control groups was made randomly. In the test group, a calcium sulphate barrier membrane, and in control group, a collagen membrane, was used in conjunction with decalcified freezedried bone graft in both sides. Ancillary parameters as well as soft tissue parameters along with radiographs were taken at baseline and after 6 months of surgery. Parameters assessed were plaque index, modified gingival index, probing depth, relative attachment level, and location of the gingival margin. A Student’s t-test was done for intragroup and a paired t-test for intergroup analysis. Results: Intragroup analysis revealed statistically significant improvement in all the ancillary parameters and soft tissue parameters with no statistically significant difference in intergroup analysis. Conclusions: The study concluded that a calcium sulphate barrier was comparable to collagen membrane in achieving clinical benefits and hence it can be used as an economical alternative to collagen membrane.

Evaluation of calcium sulphate barrier to collagen membrane in intrabony defects

Budhiraja, Shilpa,Bhavsar, Neeta,Kumar, Santosh,Desai, Khushboo,Duseja, Sareen Korean Academy of Periodontology 2012 Journal of Periodontal & Implant Science Vol.42 No.6

Purpose: The aim of this study was to clinically and radiographically evaluate and compare treatment of intrabony defects with the use of decalcified freeze-dried bone allograft in combination with a calcium sulphate barrier to collagen membrane. Methods: Twelve patients having chronic periodontal disease aged 20 to 50 years and with a probing depth >6 mm were selected. Classification of patient defects into experimental and control groups was made randomly. In the test group, a calcium sulphate barrier membrane, and in control group, a collagen membrane, was used in conjunction with decalcified freeze-dried bone graft in both sides. Ancillary parameters as well as soft tissue parameters along with radiographs were taken at baseline and after 6 months of surgery. Parameters assessed were plaque index, modified gingival index, probing depth, relative attachment level, and location of the gingival margin. A Student's t-test was done for intragroup and a paired t-test for intergroup analysis. Results: Intragroup analysis revealed statistically significant improvement in all the ancillary parameters and soft tissue parameters with no statistically significant difference in intergroup analysis. Conclusions: The study concluded that a calcium sulphate barrier was comparable to collagen membrane in achieving clinical benefits and hence it can be used as an economical alternative to collagen membrane.