Investigating the temporal dynamics of electroencephalogram (EEG) microstates using recurrent neural networks

Electroencephalogram (EEG) microstates that represent quasi‐stable, global neuronal activity are considered as the building blocks of brain dynamics. Therefore, the analysis of microstate sequences is a promising approach to understand fast brain dynamics that underlie various mental processes. Recent studies suggest that EEG microstate sequences are non‐Markovian and nonstationary, highlighting the importance of the sequential flow of information between different brain states. These findings inspired us to model these sequences using Recurrent Neural Networks (RNNs) consisting of long‐short‐term‐memory (LSTM) units to capture the complex temporal dependencies. Using an LSTM‐based auto encoder framework and different encoding schemes, we modeled the microstate sequences at multiple time scales (200–2,000 ms) aiming to capture stably recurring microstate patterns within and across subjects. We show that RNNs can learn underlying microstate patterns with high accuracy and that the microstate trajectories are subject invariant at shorter time scales (≤400 ms) and reproducible across sessions. Significant drop in the reconstruction accuracy was observed for longer sequence lengths of 2,000 ms. These findings indirectly corroborate earlier studies which indicated that EEG microstate sequences exhibit long‐range dependencies with finite memory content. Furthermore, we find that the latent representations learned by the RNNs are sensitive to external stimulation such as stress while the conventional univariate microstate measures (e.g., occurrence, mean duration, etc.) fail to capture such changes in brain dynamics. While RNNs cannot be configured to identify the specific discriminating patterns, they have the potential for learning the underlying temporal dynamics and are sensitive to sequence aberrations characterized by changes in metal processes. Empowered with the macroscopic understanding of the temporal dynamics that extends beyond short‐term interactions, RNNs offer a reliable alternative for exploring system level brain dynamics using EEG microstate sequences.     

Azithromycin resistance and its molecular characteristics in Neisseria gonorrhoeae isolates from a tertiary care centre in North India

Treatment guidelines for management of uncomplicated gonorrhoeae have been recently modified owing to alarming upsurge in azithromycin resistance. This study investigated the prevalence and genetic determinants of gonococcal azithromycin resistance in India. Four (5.7%) of 70 gonococcal isolates were resistant to azithromycin. Of 16 isolates investigated for molecular mechanisms of resistance, 13 (81.3%) and 6 (37.5%) isolates exhibited mutations in coding and promoter regions of mtrR gene, respectively. However, ermA, ermB and ermC genes or mutations in rrl gene were absent in all isolates. Azithromycin resistance is low in India posing no immediate threat to use of dual-therapy for syndromic management.     

Use of a composite pedicled muscle flap and rhBMP-7 for mandibular reconstruction

The aim of this study was to investigate the feasibility of reconstructing critical size continuity osteoperiosteal defects of the mandible using a composite of recombinant BMP-7 contained in a bovine type-1 collagen carrier wrapped in a pedicled sterno-occipitalis muscle flap. At 3 months following surgery, bridging of the surgical defect was noted in three subjects (60%). Histologically, the induced bone regenerate showed maturation from woven to lamellar bone. Islands of cartilage were distributed throughout the defect. Replacement ossification of the degenerated muscle was a common feature in all specimens. Microradiography showed a gradual increase in the calcification of mineralized tissue from the margin to the centre of the newly generated bone. This research represents a proof of the concept that bone can be satisfactorily formed within a muscular scaffolding at the site of the created defect in a one-stage procedure.     

Sphingolipids Mediate Differential Echinocandin Susceptibility in Candida albicans and Aspergillus nidulans

The cell wall synthesis-inhibiting echinocandins, including caspofungin and micafungin, play important roles in the treatment of candidiasis and aspergillosis. Previous studies revealed that, in the haploid yeast Candida glabrata, sphingolipid biosynthesis pathway mutations confer caspofungin reduced susceptibility (CRS) but micafungin increased susceptibility (MIS). Here, we describe one Candida albicans strain (of 10 tested) that similarly yields CRS-MIS mutants at relatively high frequency. Mutants demonstrated increased levels of long-chain bases (sphingolipid pathway intermediates) and, unique to this strain, loss of His104/Pro104 heterozygosity in the TSC13-encoded enoyl reductase. CRS-MIS was similarly observed in a C. albicans homozygous fen1Δ fen12Δ laboratory strain and in diverse wild-type strains following exogenous long-chain-base treatment. Analogous to these results, CRS-MIS was demonstrated in an Aspergillus nidulans basA mutant encoding defective sphingolipid C₄-hydroxylase and in its wild-type parent exposed to long-chain bases. Sphingolipids likely modulate echinocandin interaction with their Fks membrane target in all susceptible fungi, with potential implications for optimizing therapy with existing antifungals and the development of novel agents.     

Carcinoma presenting as idiopathic anterior glottic webs: A case series

An anterior glottic web is an abnormal fusion of the anterior aspect of the membranous vocal folds. Noncongenital glottic webs are usually iatrogenic from intubation or laryngeal surgery. We present six adult patients whose initial in‐office diagnoses were consistent with “idiopathic” benign anterior glottic webs as determined by three laryngologists (a.m.k. , j.m.b. , m.j.p. ). Further evaluation revealed the diagnoses of laryngeal squamous cell carcinoma in all cases. The high risk of malignancy in cases of idiopathic anterior glottic web necessitates biopsy for tissue diagnosis of all such lesions. Laryngoscope, 129:2118–2120, 2019     

Retraction of " Lung Cancer:MicroRNA and Target Database.Zhongguo Fei Ai Za Zhi,2012,15(7):429-434"

We would retract our article from Chinese Journal of Lung Cancer (published in the July 2012 issue of Chinese Journal ofLung Cancer)1due to