Solution Combustion Synthesis of Nanoscale Materials.

Solution combustion is an exciting phenomenon, which involves propagation of self-sustained exothermic reactions along an aqueous or sol-gel media. This process allows for the synthesis of a variety of nanoscale materials, including oxides, metals, alloys, and sulfides. This Review focuses on the analysis of new approaches and results in the field of solution combustion synthesis (SCS) obtained during recent years. Thermodynamics and kinetics of reactive solutions used in different chemical routes are considered, and the role of process parameters is discussed, emphasizing the chemical mechanisms that are responsible for rapid self-sustained combustion reactions. The basic principles for controlling the composition, structure, and nanostructure of SCS products, and routes to regulate the size and morphology of the nanoscale materials are also reviewed. Recently developed systems that lead to the formation of novel materials and unique structures (e.g., thin films and two-dimensional crystals) with unusual properties are outlined. To demonstrate the versatility of the approach, several application categories of SCS produced materials, such as for energy conversion and storage, optical devices, catalysts, and various important nanoceramics (e.g., bio-, electro-, magnetic), are discussed.

Lipase-catalyzed process for biodiesel production: protein engineering and lipase production.

Biodiesel is an environment-friendly and renewable fuel produced by transesterification of various feedstocks. Although the lipase-catalyzed biodiesel production has many advantages over the conventional alkali catalyzed process, its industrial applications have been limited by high-cost and low-stability of lipase enzymes. This review provides a general overview of the recent advances in lipase engineering, including both protein modification and production. Recent advances in biotechnology such as in protein engineering, recombinant methods and metabolic engineering have been employed but are yet to impact lipase engineering for cost-effective production of biodiesel. A summary of the current challenges and perspectives for potential solutions are also provided.

An Exposition on Surgical Experiences in Identification, Exposure, and Injuries of Recurrent Laryngeal Nerve (RLN) During Thyroid Operations: Gleanings, Narrative, and the Reflections.

BACKGROUND: Identifying and preserving the recurrent laryngeal nerve (RLN) is of paramount importance during thyroid surgeries. Iatrogenic injuries to RLN (RLNI) are considered one of the most serious and feared complications of thyroidectomies. Surgically, there are four routes/approaches (lateral, inferior, superior, and medial) for localizing and identifying the RLN. This study aims to estimate the incidence of RLNI in the context of various approaches taken intra-operatively for nerve localization and identification. MATERIALS AND METHODS: This retrospective analytical study included 54 cases of thyroidectomies operated for various benign and malignant thyroid disorders in a tertiary care center from January 2018 to December 2020. Intraoperative search, identification, and dissection of the nerve were done with superior, inferior, medial, and lateral approaches. The chi-square test and exact test were used to analyze the data and p-value < 0.05 was considered significant. Pre- and post-operative recurrent laryngeal nerve evaluation was done with 90 degrees Hopkins laryngoscope. RESULTS: Overall in this series, the incidence of post-thyroidectomy RLNI was 3.7% and 3.7% for permanent and temporary nerve insults, respectively. Non-recurrent RLN on the right side was identified in one case and extra-laryngeal branching of RLN was identified in two cases. There was no statistically significant difference (p = 0.929) between the different approaches taken and the incidence of RLNI. The type of surgery and pathology also expressed no statistically significant relevance with the incidence of RLNI (p = 0.463 and p = 0.277, respectively). CONCLUSION: Adoption of a particular surgical approach to localize and identify RLN during thyroid surgery carries no statistically significant difference between RLNI and approaches taken. Meticulous handling and dissection of the tissue in the correct surgical plane are crucial determinants in preventing RLNIs.

Considerations on Ossicular Reconstruction Using Lenticular Prosthesis for the Necrosed Lenticular Process During Endoscopic Tympanoplasty in Chronic Otitis Media (Mucosal) Cases.

Purpose: To evaluate hearing outcome and fate of LPIRP (lenticular process of incus replacement prosthesis) prosthesis in the reconstruction of erosion of long process of the incus. Methods: In this retrospective descriptive study 17 patients with erosion of long process of incus who were operated (reconstructed with LPIRP prosthesis) between January 2015 to December 2017 in a tertiary care center were included. The hearing outcome was evaluated by comparing mean PTA and mean ABG preoperatively and postoperatively at the end of 3 months and 18 months. The graft uptake rate, reperforation, and extrusion of the prosthesis were assessed using otoendoscopy. Results: Preoperative mean PTA was 53.8 dB while mean postoperative PTA was 36.6 dB and 33.4 dB at the end of 3 and 18 months respectively (p-value ˂ 0.05). The mean preoperative ABG was 30.2 dB while the postoperative mean was 13.4 dB and 11.2 dB at the end of 3 months and 18 months respectively (p < 0.05). Extrusion with re-perforation was seen only in one case 1/17 (5.8%). Conclusion: LPIRP has all the characteristics for an ideal middle ear implant which is a cost-effective alternative in the reconstruction of an eroded long process of the incus. Supplementary Information: The online version contains supplementary material available at 10.1007/s12070-022-03317-5.

Contemporary Plural Deliberations and Perspectives in Revision Middle Ear Surgery. Causes, Outcomes and Lessons Learned.

The indications for revision middle ear surgery are inter-linked to the objectives of surgery and needs of the patient. Revision middle ear surgery is often challengingly arduous not only for the patient but for the surgeon as well. This study concentrates on the causes of failures of primary ear surgery, indications, techniques, outcomes and lessons learned in revision ear surgery. This retrospectivedescriptive study included 22 cases (12.29%) of revision surgery,with a follow up of at least one year, out of total 179 cases of middle ear surgeries performed over a period of 5 years.These revision cases included tympanoplasty, cortical mastoidectomy and modified radical mastoidectomy alongwith ossiculoplasty and scutumplasty, wherever required. Hearing improvement, closure of perforation, and prevention of recrudescence were the main outcome parameters. The overall morphologic success of revision surgery in our series was 90.90%.There was one graft failure, one attic retraction and the main complication observed was post-operative worsening of hearing.Mean postoperative pure-tone average air -bone gap (ABG) was 20.86 ± 11.29 dB compared with preoperative ABG of 29.64 ± 10.63 dB and the difference was statistically significant ( p < 0.05) with p value 0.0112 on paired t-test. Detailed knowledge and anticipation of the cause of failure is a must in preventing another failure in revision ear surgeries. Hearing preservation must be considered in a pragmatic perspective and accordingly surgical indications must complement the realistic and reasonable expectations of the patients.

Role of Pre Auricular Flap in Reconstruction of Acquired Meatal Stenosis Via Endaural Approach.

Acquired meatal stenosis is a difficult entity to treat with a significant recurrence rate. It is normally approached posteriorly via post aural approach and reconstructed using split thickness skin graft. We are presenting a novel method of surgery for acquired meatal stenosis using a pre auricular flap via endaural approach only. The aim was to evaluate the success rate of using a pre auricular flap in acquired atresia of the external auditory canal using the endaural approach. Twenty patients with acquired atresia of the external auditory canal that was surgically treated were retrospectively studied from July 2012 to July 2018. All cases were done using endaural approach only. During the surgery, the atretic tissue was removed, wide canaloplasty done and the stenotic segment widened. Reconstruction of the external auditory canal was done using a pedicled anteriorly based pre auricular flap rotating it into the external auditory canal to cover the bare bone. Of the 20 patrients there were good results in 18 patients with restenosis occurring only in 2 patients. However, a skin tag developed in 2 other patients which was excsiced as OPD procedure and patient was asymptomatic on further follow ups. In all the 20 cases preauricular flap was used for reconstruction along with use of Split thickness skin graft in 10 cases. All 20 cases were operated via endaural route only. Use of a Preauricular flap in surgical treatment of acquired aural stenosis gives good results with a wide dry cavity as the flap is pedicled with its vascular supply and it can be tailor made according to each case and requirement.

An Exposition on Endoscopic Broad Palisade Cartilage Tympanoplasty: Procedural Illustrations and Connotations in Context of Audiological and Morphological Outcomes.

The objective of this study was to evaluate graft take up rate and hearing improvement in type I and type III endoscopic tympanoplasty using broad palisade cartilage graft and to compare the results with other studies who have used single piece cartilage as graft. This retrospective observational descriptive study was done in a tertiary care hospital. This study included 64 cases, who met the inclusion criteria, which were operated over 2 years and were followed for 3 years. The results were evaluated using graft uptake rates and hearing improvement comparing the preoperative and postoperative air conduction threshold (ACT) and air bone gap closure (ABG). The graft take rate was 92.1% and 87.5% at the end of 1 year and 3 years respectively. The preoperative and post-operative air conduction threshold were 35 ± 6.0 dB HL and 17.5 ± 2.7 dB HL in type I tympanoplasty respectively (p value <0.0001) while in type III tympanoplasty, preoperative and post-operative air conduction threshold (ACT) were 43.3 ± 8.6 dB HL and 23.1 ± 4.2 dB HL respectively (p value <0.0001). The preoperative and postoperative air bone gap (ABG) were 29.0 ± 5.6 dB HL and 14.4 ± 4.20 dB HL in type I tympanoplasty respectively (p value <0.0001). In type III preoperative and post-operative air bone gap were 36. 1 ± 7.5 dB HL and 16.4 ± 3.3 dB HL respectively (p value < 0.0001). Endoscopic broad palisade cartilage tympanoplasty has similar outcomes in morphological and audio logical perspectives as single piece cartilage tympanoplasty. Further studies with long term follow up period are required to corroborate the result of this study.

The Emerging Surgical Concepts and Principles of Attic and Postero-Superior Wall Reconstruction by Auricular Cartilage and Free Fibro-Periosteal Tissue in Middle Ear Surgery. An Exposition on Surgical Experiences, Observations and Mistakes.

In middle ear surgeries, addressing the pathologies (cholesteatoma, retractions or tympanosclerosis) in attic or postero-superior area, are associated with difficulties like reconstruction of attic and postero-superior canal wall after clearing the disease. There are various graft materials available for such attic reconstruction in intact canal -wall surgeries. We describe our experience of attic and postero-superior canal wall reconstruction in combined approach tympanoplasty (CAT) using free auricular cartilage and free fibro-periosteal tissue and to present our results in anatomical and functional perspectives. This retrospective observational study was conducted in a tertiary care center which comprised 25 cases of combined approach tympanoplasty (with attic wall reconstruction) which were operated for attic cholesteatoma, tympanosclerosis or adhesive otitis media from January 2017 to December 2019 in our otolaryngology department. Outcomes were evaluated in audiological and morphological dimensions and paired "t" test (significant p value < 0.05) was used to analyse the audiological data. A total of 25 cases (22 primary and 3 revision cases) were included in the study. Defect in attic and posterosuperior canal wall was caused by pathology (disease itself) in 2 cases, surgically created (intraoperatively to clear the disease) in 11 cases and both by pathology and surgically in 12 cases. 22 cases had successful graft uptake, with a morphological success rate of 88%, whereas graft failure was encountered in 3 cases. Complications observed were post-operative otorrhea (2 cases), recurrence (3 cases), no hearing improvement despite intact graft (1 case) and worsening of hearing post operatively in 1 case. Pre-operative ACT (Air conduction threshold) was 45.96 ± 12.47 dB and the post-operative ACT was 38.61 ± 9.76 dB (p value = 0.0246). Pre-operative ABG (Air-bone gap) was reduced from 30.58 ± 11.06 dB to the post-operative ABG of 21.89 ± 6.24 dB (p value = 0.0013). Reconstruction of postero-superior canal wall and attic defects in CAT using auricular cartilage and fibro-periosteal tissue (over mastoid cortex) is a novel method and associated with satisfactory morphological and audiological results. It is also effective in preventing postoperative retractions.

Extra-Rhino Cerebral Manifestations of Mucormycosis in Head and Neck Region: An Insight.

Mucormycosis is a potentially life-threatening fungal infection with a high mortality rate. The difficulty and delay in diagnosis due to its rarity usually results in a poor prognosis. Most common site in head and neck region is the nose and paranasal sinuses. However there are other very unusual areas in head and neck region where mucormycosis is encountered. Knowledge of these unusual areas is must and can save a patient's life. To elaborate and highlight the unusual areas in head and neck region where mucormycosis can mimic other common diseases. This retrospective study was done from May 2010 to May 2019 over a period of 9 years. All histopathologically confirmed cases of Head and Neck mucormycosis were evaluated and data analyzed. Total 35 cases of head neck mucormycosis were encountered from May 2010 to May 2019 over a period of 9 years. Out of which 30 cases (85.72%) were of rhino-orbito-cerebral mucormycosis and 5 cases (14.28%) were EXTRA rhino-orbito-cerebral mucormycosis in head neck region. Mucormycosis at such unusual sites can cause diagnostic dilemma for the treating doctor. Clinical knowledge with anticipation is a must for success in treatment of mucormycosis in unusual places in head neck region especially when normal looking diseases does not respond to usual treatment.

Tragal Perichondrium and Composite Cartilage Graft Complimenting Endoscopic Tympanoplasty in True Sense: A Comparison.

INTRODUCTION: In days of scar less surgeries it has become necessary for otologists to concentrate on tympanoplasties without external incisions. This study compares the anatomical and functional results of tragal perichondrium graft and perichondrium-cartilage composite graft for transcanal endoscopic tympanoplasties in Himalayan region. METHODS AND MATERIALS: This prospective study included 60 subjects of chronic otitis media (mucosal type), who underwent transcanal endoscopic underlay type I tympanoplasty and were divided into two groups. In 30 cases tragal perichondrium graft and in rest of 30 cases Tragal perichondrium Cartilage composite graft was used. Anatomical and functional outcomes were evaluated at 6 months time. RESULTS: Hearing gain comparing Audiometric data between the tragal perichondrial graft group and tragal perichondrial cartilage composite graft group at 6 months showed no statistically significant differences (P= 0.9533). Assessment of anatomical outcome indicated a greater number of complications in the tragal perichondrial graft group although it was not statistically significant (P=0.6360 in anterior graft failure group, P =0.1322 in reperforation group and P= 0.1056 in retraction group). CONCLUSION: Functional results validated both the grafting material while anatomical results are slightly better in tragal perichondrial cartilage composite graft group in term of re perforation and retraction. Moreover use of tragal grafts endoscopic tympanoplasty fulfils its true meaning as no visible scar and post operative patient morbidity is prevented.

A Perspective of Clinical Behaviour and Management of Deep Neck Space Infections (DNSI): The Clinical Conundrum.

The diagnosis and management of deep neck space infections remain a challenging task for otolaryngologists. A retrospective observational analysis of 137 cases of deep neck infections at a tertiary care centre was reviewed. We present 137 treated cases of DNSIs in a retrospective 5 years clinical study conducted in the department of otolaryngology at a tertiary care center from January 2012 to December 2016. Demographic information, Socio-economic data, etiopathogenesis, clinical presentation, spaces involved, diagnosis, and treatment strategies, associated morbidities, course and complications were analysed and compared with past experiences. Odontogenic and salivary gland infections causes were the most common source of DNIs. Major complication observed was skin defect. In this study, submandibular space infection was found to be the most common space involved in DNSI. Pain (100%) was the most common clinical complaint followed by neck swelling (65.69%). Staphylococcus aureus (38 cases) was the most common micro-organism isolated. Surgical intervention was the main modality of treatment and there was one mortality. DNSIs are fairly common challenging and potentially lethal entities which can lead to severe complications in a very short time, should there be delay in its prompt diagnosis and management. Computerized Tomography Scan (CT scan) with contrast is the investigation of choice in diagnosing DNSIs. Assessment of airway control must take precedence.

Apparatus for studies of high-temperature chemical reactions in single particle systems.

We report a compact microgravity flight apparatus for characterization of high-temperature chemical reactions in single particle systems. The apparatus employs an infrared CO(2) laser to ignite 1-5 mm samples while video images, thermocouple measurements, laser on/off status, and XYZ accelerometer signals are synchronously recorded. Different operating modes permit preignition quenching, ignition, and combustion experiments to be performed. The apparatus was successfully utilized during microgravity experiments on board NASA research aircraft.

Binder-Free N- and O-Rich Carbon Nanofiber Anodes for Long Cycle Life K-Ion Batteries.

Carbon nanofibers produced by electrospinning of polyacrylonitrile polymer and subsequent carbonization were tested as freestanding potassium-ion anodes. The effect of oxygen functionalization on K-ion carbon anode performance was tested for the first time via plasma oxidation of prepared carbon nanofibers. The produced materials exhibited exceptional cycling stability through the amorphous carbon structuring and one-dimensional architecture accommodating significant material expansion upon K+ intercalation, resulting in a stable capacity of 170 mAh g-1 after 1900 cycles at 1C rate for N-rich carbon nanofibers. Excellent rate performance of 110 mAh g-1 at 10C rate, as compared to 230 mAh g-1 at C/10 rate, resulted from the K-ion surface storage mechanism and the increased K+ solid diffusion coefficient in carbon nanofibers as compared to graphite. Plasma oxidation treatment augmented surface storage of K+ by oxygen functionalities but increased material charge transfer resistance as compared to N-rich carbon fibers. Ex situ characterization revealed that the one-dimensional structure was maintained throughout cycling, despite the increase in graphitic interlattice spacing from 0.37 to 0.46 nm. The carbon nanofibers demonstrate great potential as an anode material for potassium-ion batteries with superior cycling stability and rate capability over previously reported carbon materials.

Electrochemical performance of MXenes as K-ion battery anodes.

Herein, we report on the electrochemical performance of two-dimensional transition metal carbonitrides as novel promising electrode materials in K-ion batteries. Titanium carbonitride, Ti3CNTz, was investigated in detail using electrochemical galvanostatic cycling at various current densities. X-ray diffraction and X-ray photoelectron spectroscopy were used to study the potassiation mechanism and its structural changes.

Randomized, Double-Blind, Phase III Trial of Ipilimumab Versus Placebo in Asymptomatic or Minimally Symptomatic Patients With Metastatic Chemotherapy-Naive Castration-Resistant Prostate Cancer.

Purpose Ipilimumab increases antitumor T-cell responses by binding to cytotoxic T-lymphocyte antigen 4. We evaluated treatment with ipilimumab in asymptomatic or minimally symptomatic patients with chemotherapy-naive metastatic castration-resistant prostate cancer without visceral metastases. Patients and Methods In this multicenter, double-blind, phase III trial, patients were randomly assigned (2:1) to ipilimumab 10 mg/kg or placebo every 3 weeks for up to four doses. Ipilimumab 10 mg/kg or placebo maintenance therapy was administered to nonprogressing patients every 3 months. The primary end point was overall survival (OS). Results Four hundred patients were randomly assigned to ipilimumab and 202 to placebo; 399 were treated with ipilimumab and 199 with placebo. Median OS was 28.7 months (95% CI, 24.5 to 32.5 months) in the ipilimumab arm versus 29.7 months (95% CI, 26.1 to 34.2 months) in the placebo arm (hazard ratio, 1.11; 95.87% CI, 0.88 to 1.39; P = .3667). Median progression-free survival was 5.6 months in the ipilimumab arm versus 3.8 with placebo arm (hazard ratio, 0.67; 95.87% CI, 0.55 to 0.81). Exploratory analyses showed a higher prostate-specific antigen response rate with ipilimumab (23%) than with placebo (8%). Diarrhea (15%) was the only grade 3 to 4 treatment-related adverse event (AE) reported in ≥ 10% of ipilimumab-treated patients. Nine (2%) deaths occurred in the ipilimumab arm due to treatment-related AEs; no deaths occurred in the placebo arm. Immune-related grade 3 to 4 AEs occurred in 31% and 2% of patients, respectively. Conclusion Ipilimumab did not improve OS in patients with metastatic castration-resistant prostate cancer. The observed increases in progression-free survival and prostate-specific antigen response rates suggest antitumor activity in a patient subset.

Engineering surface hydrophobicity improves activity of Bacillus thermocatenulatus lipase 2 enzyme.

Bacillus thermocatenulatus lipase 2 (BTL2) is a promising industrial enzyme used in biodiesel production. Although BTL2 has high thermostability and good resistance to organic solvents, the activity of BTL2 is suboptimal for industrial processes. To improve BTL2 activity, we engineered BTL2 lipase by modulating hydrophobicity of its lid domain. Through site-directed mutagenesis, we constructed three mutants, namely Y225F+S232A, S232A+T236V and Q185L, to cover all uncharged hydrophilic amino acids within the lid domain. Activities of these mutants were characterized. Our findings suggest that one mutant (Y225F+S232A) showed ∼35% activity increase in catalyzing heterogeneous hydrolytic reactions relevant for industrial applications. A mathematical framework was established to account for different molecular events that contribute to the observed apparent catalytic activities. Increases in hydrophobicity of lid domains were associated with increased interfacial adsorption of lipases and lower molecular enzymatic activities. The measured apparent activities of lipases include contributions from both events. Lid hydrophobicity can thus result in different changes in lipase activities depending on the mutation site. Our work demonstrates the feasibility of increasing BTL2 activity by modulating the hydrophobicity of lid domains and provides some guidelines for further improving BTL2 activity.