Ionic Covalent Organic Framework as a Dual Functional Sensor for Temperature and Humidity.

Visual sensing of humidity and temperature by solids plays an important role in the everyday life and in industrial processes. Due to their hydrophobic nature, most covalent organic framework (COF) sensors often exhibit poor optical response when exposed to moisture. To overcome this challenge, the optical response is set out to improve, to moisture by incorporating H-bonding ionic functionalities into the COF network. A highly sensitive COF, consisting of guanidinium and diformylpyridine linkers (TG-DFP), capable of detecting changes in temperature and moisture content is fabricated. The hydrophilic nature of the framework enables enhanced water uptake, allowing the trapped water molecules to form a large number of hydrogen bonds. Despite the presence of non-emissive building blocks, the H-bonds restrict internal bond rotation within the COF, leading to reversible fluorescence and solid-state optical hydrochromism in response to relative humidity and temperature.

Comparative evaluation of C-MAC and McGrath MAC videolaryngoscopes with Macintosh direct laryngoscope for endotracheal intubation in adult patients undergoing elective surgeries.

Background and Aims: Videolaryngoscopes have an undisputed role in difficult airway management, but their role in routine intubation scenarios remains underappreciated. McGrath MAC is a lightweight laryngoscope with a disposable blade. It remains to be proven if it performs as efficiently as the reusable videolaryngoscopes like C-MAC and whether it has an advantage over standard Macintosh laryngoscope in predicted normal airways. Material and Methods: We recruited 180 adult patients and randomly divided them into three groups for intubation with either Macintosh laryngoscope (Group-A), C-MAC (Group-B), and McGrath (Group-C). The primary objective was to compare the first attempt success rate. Secondary objectives included Cormack-Lehane (CL) grades, laryngoscopy time, intubation time, ease of intubation, need for optimization manoeuver, and the number of passes to place the endotracheal tube. Results: The two videolaryngoscopes provided a superior first attempt success rate as compared to Macintosh laryngoscope (P = 0.027). The CL grade-I was 100% in group B, 41.7% in group-A and 90% in group-C (B vs C; P = 0.037). Laryngoscopy time was 9.9 ± 2.5 s, 12.6 ± 0.8 s, and 13.1 ± 0.8 s for groups A, B, and C, respectively (B vs C; P = 0.001). Intubation time was 24.4 ± 12 s, 28.3 ± 1.9 s, and 37.3 ± 5.8 s for groups A, B, and C, respectively (P < 0.0001). The number of tube passes was highest in group C. Conclusion: Videolaryngoscopes provided a superior glottic view and resulted in a superior first attempt success rate as compared to Macintosh laryngoscope. When comparing the two videolaryngoscopes, C-MAC resulted in better intubation characteristics (shorter intubation time, better glottic views, and higher first-attempt success rates) and should be preferred over McGrath for intubation in adult patients with normal airways.

Force Decomposition Analysis: A Method to Decompose Intermolecular Forces into Physically Relevant Component Contributions.

Computational quantum chemistry can be more than just numerical experiments when methods are specifically adapted to investigate chemical concepts. One important example is the development of energy decomposition analysis (EDA) to reveal the physical driving forces behind intermolecular interactions. In EDA, typically the interaction energy from a good-quality density functional theory (DFT) calculation is decomposed into multiple additive components that unveil permanent and induced electrostatics, Pauli repulsion, dispersion, and charge-transfer contributions to noncovalent interactions. Herein, we formulate, implement, and investigate decomposing the forces associated with intermolecular interactions into the same components. The resulting force decomposition analysis (FDA) is potentially useful as a complement to the EDA to understand chemistry, while also providing far more information than an EDA for data analysis purposes such as training physics-based force fields. We apply the FDA based on absolutely localized molecular orbitals (ALMOs) to analyze interactions of water with sodium and chloride ions as well as in the water dimer. We also analyze the forces responsible for geometric changes in carbon dioxide upon adsorption onto (and activation by) gold and silver anions. We also investigate how the force components of an EDA-based force field for water clusters, namely MB-UCB, compare to those from force decomposition analysis.

Are we ready to manage an opioid epidemic in the intensive care unit?

The current opioid epidemic has had a massive impact on the critical care sector. This is due to an increase in the number of acute opioid overdose-related admissions and the number of opioid-dependent and opioid-tolerant patients admitted to intensive care units (ICUs). This review discusses the challenges that intensive care physicians face when caring for patients suffering from opioid-related disorders and analyses existing solutions. Preference for non-opioid analgesics, treatment of acute pain in the ICUs to avoid chronic pain syndrome, and education of patients and caregivers are critical to preventing this pandemic.

NewtonNet: a Newtonian message passing network for deep learning of interatomic potentials and forces.

We report a new deep learning message passing network that takes inspiration from Newton's equations of motion to learn interatomic potentials and forces. With the advantage of directional information from trainable force vectors, and physics-infused operators that are inspired by Newtonian physics, the entire model remains rotationally equivariant, and many-body interactions are inferred by more interpretable physical features. We test NewtonNet on the prediction of several reactive and non-reactive high quality ab initio data sets including single small molecules, a large set of chemically diverse molecules, and methane and hydrogen combustion reactions, achieving state-of-the-art test performance on energies and forces with far greater data and computational efficiency than other deep learning models.

A benchmark dataset for Hydrogen Combustion.

The generation of reference data for deep learning models is challenging for reactive systems, and more so for combustion reactions due to the extreme conditions that create radical species and alternative spin states during the combustion process. Here, we extend intrinsic reaction coordinate (IRC) calculations with ab initio MD simulations and normal mode displacement calculations to more extensively cover the potential energy surface for 19 reaction channels for hydrogen combustion. A total of ∼290,000 potential energies and ∼1,270,000 nuclear force vectors are evaluated with a high quality range-separated hybrid density functional, ωB97X-V, to construct the reference data set, including transition state ensembles, for the deep learning models to study hydrogen combustion reaction.

Development of a Many-Body Force Field for Aqueous Alkali Metal and Halogen Ions: An Energy Decomposition Analysis Guided Approach.

Aqueous solutions of alkyl/alkaline metal and halide ions play a crucial functional role in biological systems such as proteins, membranes, and nucleic acids and for interfacial chemistry in geomedia and in the atmosphere. We present the MB-UCB many-body force field for monovalent and divalent ions that includes polarization, charge penetration to describe the short-range permanent electrostatics accurately, as well as a model for charge transfer to better describe the quantum mechanical potential energy surface and its components obtained from the absolutely localized molecular orbital energy decomposition analysis (ALMO-EDA). We find that the MB-UCB force field is in very good agreement with a validation suite of ion-ion and ion-water cluster data, exhibiting overall better cancellation of errors among energy components, unlike the case for other many-body potentials that do not utilize an EDA scheme. However, limitations in the functional form for the classical many-body energy components do limit the best achievable accuracy through complete cancellation of error and warrant further study.

Comparative Evaluation of C-MAC Videolaryngoscope with Macintosh Direct Laryngoscope in Patients with Normal Airway Predictors.

Background: Video laryngoscopes (VL) assist in securing the airway faster and more accurately in difficult airways. However, data regarding its usefulness in patients with normal airways are sparse. Aim: We designed this study to compare the ease and success of endotracheal intubation between C-MAC and Macintosh direct laryngoscope (DL) in adult patients with no anticipated airway difficulty. Settings and Design: The design involves prospective randomized case - control study. Subjects and Methods: One hundred and twenty adult patients with predicted normal airway were randomized into two groups and were intubated using VL (C-MAC VL) and DL (Macintosh DL), respectively. The Cormack-Lehane (CL) grade, time taken for intubation, attempts taken (number), and need for laryngeal maneuvers or stylets were recorded and analyzed for statistical significance. Results: Thirty-eight patients in the DL group and 48 patients in the VL group had CL I view, 20 patients in the DL group and 16 patients in the VL group had CL II, and two patients in the DL group had CL III view. None of the patients in Group VL had CL III view. In seven out of 60 cases in the DL group, difficulty was experienced during insertion of the laryngoscope blade as compared to two cases out of 60 in the VL group. The mean time taken for intubation was lesser in Group DL (28.48 s) as compared to 39.3 s in Group VL. Nine patients in Group DL and 16 patients in Group VL required external laryngeal manipulation. Stylets were used, in seven patients in group DL and in 11 patients in group VL. Conclusions: In patients with a predicted normal airway, C-MAC provides a better glottic view compared to Macintosh DL. Time taken for intubation using the C-MAC video laryngoscope was more. However, success rates on the first attempt at endotracheal intubation and the number of intubation attempts with either laryngoscope were similar.

New Threat at Doorstep: What an Intensivist should Know.

How to cite this article: Das AK, Sharma A, Kumar S, Goyal S, Kothari N. New Threat at Doorstep: What an Intensivist should Know. Indian J Crit Care Med 2022;26(10):1076-1077.

Social Stigma of COVID-19 Experienced by Frontline Healthcare Workers of Department of Anaesthesia and Critical Care of a Tertiary Healthcare Institution in Delhi.

BACKGROUND: Social stigma is associated with Coronavirus Disease-2019 (COVID-19) particularly against people who have contracted the disease or have come in contact with it. There is paucity of studies regarding the prevalence of social stigma against healthcare workers (HCWs) in COVID-19 hospitals in India. The objective of this study was to measure social stigma faced by frontline HCWs of Department of Anaesthesia and Critical Care in a COVID-19 hospital and to assess the relationship between sociodemographic characteristics and social stigma. PATIENTS AND METHODS: A cross-sectional study using a questionnaire (sociodemographic characteristics along with modified Berger HIV Stigma Scale) was conducted from October 10, 2020 to October 30, 2020, in the Department of Anaesthesia and Critical Care. The survey was distributed among frontline HCWs using Google Forms as well as Bilingual Physical Form. Total stigma and subgroups of stigma scale were measured for different sociodemographic parameters and compared. Data were presented as mean ± standard deviation. p-value <0.05 was taken as significant. RESULTS: Out of 120 frontline HCWs participated in the study, 68 (56.6%) reported severe level of COVID-19-related stigma. The mean score of COVID-19-related stigma was 41 + 7.69. Mean scores for subgroups of stigma scale, i.e., personalized stigma, disclosure concerns, negative self-image, and concerns with public attitude, were 15.60 + 4.01, 6.68 + 3.21, 5.46 + 3.22, and 13.25 + 2.44, respectively. In the univariate analysis, the overall COVID-19-related stigma scores were associated with age >30 years, male gender, lower designation (technicians and nursing orderly), lesser education, and married HCWs. In logistic regression model, only male gender was significantly associated with severity of COVID-19 stigma. CONCLUSION: This study concluded that more than half of frontline HCWs in the Department of Anaesthesia and Critical Care experienced severe social stigma during COVID-19 pandemic, with highest stigma in concerns with public attitude subgroup. Severity of stigma was associated with age, male gender, designation, education, and marital status of HCW. HIGHLIGHTS: Frontline HCWs of Department Anaesthesia and Critical Care experienced significant stigma related to COVID-19. HOW TO CITE THIS ARTICLE: Jain S, Das AK, Talwar V, Kishore J, Heena, Ganapathy U. Social Stigma of COVID-19 Experienced by Frontline Healthcare Workers of Department of Anaesthesia and Critical Care of a Tertiary Healthcare Institution in Delhi. Indian J Crit Care Med 2021;25(11):1241-1246.

Opium Addiction: Practical Issues in ICU.

How to cite this article: Das AK, Sharma A, Kothari N, Goyal S. Opium Addiction: Practical Issues in ICU. Indian J Crit Care Med 2021;25(9):1082-1083.

Multipolar Force Fields for Amide-I Spectroscopy from Conformational Dynamics of the Alanine Trimer.

The dynamics and spectroscopy of N-methyl-acetamide (NMA) and trialanine in solution are characterized from molecular dynamics simulations using different energy functions, including a conventional point charge (PC)-based force field, one based on a multipolar (MTP) representation of the electrostatics, and a semiempirical DFT method. For the 1D infrared spectra, the frequency splitting between the two amide-I groups is 10 cm-1 from the PC, 13 cm-1 from the MTP, and 47 cm-1 from self-consistent charge density functional tight-binding (SCC-DFTB) simulations, compared with 25 cm-1 from experiment. The frequency trajectory required for the frequency fluctuation correlation function (FFCF) is determined from individual normal mode (INM) and full normal mode (FNM) analyses of the amide-I vibrations. The spectroscopy, time-zero magnitude of the FFCF C(t = 0), and the static component Δ02 from simulations using MTP and analysis based on FNM are all consistent with experiments for (Ala)3. Contrary to this, for the analysis excluding mode-mode coupling (INM), the FFCF decays to zero too rapidly and for simulations with a PC-based force field, the Δ02 is too small by a factor of two compared with experiments. Simulations with SCC-DFTB agree better with experiment for these observables than those from PC-based simulations. The conformational ensemble sampled from simulations using PCs is consistent with the literature (including PII, ß, αR, and αL), whereas that covered by the MTP-based simulations is dominated by PII with some contributions from ß and αR. This agrees with and confirms recently reported Bayesian-refined populations based on 1D infrared experiments. FNM analysis together with a MTP representation provides a meaningful model to correctly describe the dynamics of hydrated trialanine.

Configurational Entropy of Folded Proteins and Its Importance for Intrinsically Disordered Proteins.

Many pairwise additive force fields are in active use for intrinsically disordered proteins (IDPs) and regions (IDRs), some of which modify energetic terms to improve the description of IDPs/IDRs but are largely in disagreement with solution experiments for the disordered states. This work considers a new direction-the connection to configurational entropy-and how it might change the nature of our understanding of protein force field development to equally well encompass globular proteins, IDRs/IDPs, and disorder-to-order transitions. We have evaluated representative pairwise and many-body protein and water force fields against experimental data on representative IDPs and IDRs, a peptide that undergoes a disorder-to-order transition, for seven globular proteins ranging in size from 130 to 266 amino acids. We find that force fields with the largest statistical fluctuations consistent with the radius of gyration and universal Lindemann values for folded states simultaneously better describe IDPs and IDRs and disorder-to-order transitions. Hence, the crux of what a force field should exhibit to well describe IDRs/IDPs is not just the balance between protein and water energetics but the balance between energetic effects and configurational entropy of folded states of globular proteins.

From Intermolecular Interaction Energies and Observable Shifts to Component Contributions and Back Again: A Tale of Variational Energy Decomposition Analysis.

Quantum chemistry in the form of density functional theory (DFT) calculations is a powerful numerical experiment for predicting intermolecular interaction energies. However, no chemical insight is gained in this way beyond predictions of observables. Energy decomposition analysis (EDA) can quantitatively bridge this gap by providing values for the chemical drivers of the interactions, such as permanent electrostatics, Pauli repulsion, dispersion, and charge transfer. These energetic contributions are identified by performing DFT calculations with constraints that disable components of the interaction. This review describes the second-generation version of the absolutely localized molecular orbital EDA (ALMO-EDA-II). The effects of different physical contributions on changes in observables such as structure and vibrational frequencies upon complex formation are characterized via the adiabatic EDA. Example applications include red- versus blue-shifting hydrogen bonds; the bonding and frequency shifts of CO, N2, and BF bound to a [Ru(II)(NH3)5]2 + moiety; and the nature of the strongly bound complexes between pyridine and the benzene and naphthalene radical cations. Additionally, the use of ALMO-EDA-II to benchmark and guide the development of advanced force fields for molecular simulation is illustrated with the recent, very promising, MB-UCB potential.

A Reactive Force Field with Coarse-Grained Electrons for Liquid Water.

Nonreactive force fields are defined by perturbations of electron density that are relatively small, whereas chemical reactivity involves wholesale electronic rearrangements that make and break bonds. Thus, reactive force fields are incredibly difficult to develop compared to nonreactive force fields, yet at the same time, they fill a critical need when ab initio molecular dynamics methods are not affordable. We introduce a new reactive force field model for water that combines modified nonbonded terms of the ReaxFF model and its embedding in the electrostatic interactions described by our recently introduced coarse-grained electron model (C-GeM). The ReaxFF/C-GeM force field is characterized for many energetic and dissociative water properties for water clusters, structure, and dynamical properties under ambient conditions in the condensed phase, as well as the temperature dependence of density and water diffusion, with very good agreement with experiment. The ReaxFF/C-GeM force field should be more transferable and more broadly applicable to a range of reactive systems involving both proton and electron transfer in the condensed phase.