Snow viruses and their implications on red snow algal blooms.

Algal blooms can give snowmelt a red color, reducing snow albedo and creating a runaway effect that accelerates snow melting. The occurrence of red snow is predicted to grow in polar and subpolar regions with increasing global temperatures. We hypothesize that these algal blooms affect virus-bacteria interactions in snow, with potential effects on snowmelt dynamics. A genomic analysis of double-stranded DNA virus communities in red and white snow from the Whistler region of British Columbia, Canada, identified 792 putative viruses infecting bacteria. The most abundant putative snow viruses displayed low genomic similarity with known viruses. We recovered the complete circular genomes of nine putative viruses, two of which were classified as temperate. Putative snow viruses encoded genes involved in energy metabolisms, such as NAD+ synthesis and salvage pathways. In model phages, these genes facilitate increased viral particle production and lysis rates. The frequency of temperate phages was positively correlated with microbial abundance in the snow samples. These results suggest the increased frequency of temperate virus-bacteria interactions as microbial densities increase during snowmelt. We propose that this virus-bacteria dynamic may facilitate the red snow algae growth stimulated by bacteria.IMPORTANCEMicrobial communities in red snow algal blooms contribute to intensifying snowmelt rates. The role of viruses in snow during this environmental shift, however, has yet to be elucidated. Here, we characterize novel viruses extracted from snow viral metagenomes and define the functional capacities of snow viruses in both white and red snow. These results are contextualized using the composition and functions observed in the bacterial communities from the same snow samples. Together, these data demonstrate the energy metabolism performed by viruses and bacteria in a snow algal bloom, as well as expand the overall knowledge of viral genomes in extreme environments.

Human microglia show unique transcriptional changes in Alzheimer's disease.

Microglia, the innate immune cells of the brain, influence Alzheimer's disease (AD) progression and are potential therapeutic targets. However, microglia exhibit diverse functions, the regulation of which is not fully understood, complicating therapeutics development. To better define the transcriptomic phenotypes and gene regulatory networks associated with AD, we enriched for microglia nuclei from 12 AD and 10 control human dorsolateral prefrontal cortices (7 males and 15 females, all aged >60 years) before single-nucleus RNA sequencing. Here we describe both established and previously unrecognized microglial molecular phenotypes, the inferred gene networks driving observed transcriptomic change, and apply trajectory analysis to reveal the putative relationships between microglial phenotypes. We identify microglial phenotypes more prevalent in AD cases compared with controls. Further, we describe the heterogeneity in microglia subclusters expressing homeostatic markers. Our study demonstrates that deep profiling of microglia in human AD brain can provide insight into microglial transcriptional changes associated with AD.

Role of COPD in a case of fatal Aspergillus niger tracheobronchitis.

A man with chronic obstructive pulmonary disease (COPD) in his mid-60s was admitted for respiratory failure due to multifocal, necrotising pneumonia. Despite initial improvement with antimicrobial therapy, the patient developed hemoptysis and progressive infiltrates. Subsequent fungal cultures from his bronchoalveolar lavage were positive for Aspergillus niger and treatment with voriconazole was added for suspected invasive pulmonary aspergillosis (IPA). A repeat bronchoscopy revealed cobblestone lesions with mucosal friability throughout the lower trachea and bilateral mainstem bronchi. Endobronchial biopsy showed septated hyphae confirming the diagnosis of IPA. Despite appropriate therapy, the patient declined further and passed away on hospital day 11. Invasive infections with A. niger are infrequent, with a paucity of data on clinical course and outcomes. Our case adds to the current body of literature regarding the potential virulence of this species in patients with COPD.

Heteroacene-Based Polymer with Fast-Switching Visible-Near Infrared Electrochromic Behavior.

The electrochromic properties and application of electronically conducting polymers (ECPs) (PTRPZ-EDOT) consisting of a 3,4-ethylenedioxythiophene (EDOT) and the heteroacene-based molecular scaffold, 6H-pyrrolo[3,2-b:4,5-b'] bis [1,4] benzothiazine (TRPZ), are reported. Known for its high electron mobility and conducting properties, the novel TRPZ scaffold was synthesized to possess two EDOT molecules termini affording TRPZ-EDOT. Electropolymerization of TRPZ-EDOT resulted in remarkable spectroscopic and conductive properties suitable for electrochromic device fabrication. Using atomic force microscopy (AFM), the average surface roughness and surface topography of PTRPZ-EDOT polymer thin films were determined. Spectroelectrochemical data showed that the polymer achieved switching times of 4.07 (coloration) and 0.47 s (bleaching) at 539 nm. The PTRPZ-EDOT film exhibits an optical contrast of 36-44% at 539 nm between its neutral and colored states, respectively. The NIR region from 1000 to 1700 nm shows the appearance of charge carrier bands with a 0-1 V potential range. An electrochromic device was successfully fabricated from PTRPZ-EDOT, showcasing the potential and applicability of the polymer material for advanced technologies such as smart windows, flexible electrochromic screens, and energy storage devices.

A Case Series of Secondary Spontaneous Pneumomediastinum and Pneumothorax in Severe COVID-19 Pneumonia.

Introduction Pneumomediastinum and pneumothorax are uncommon complications in COVID-19 patients. The exact prevalence, etiology, and outcomes are not well known. We report a case series of patients in our institution with COVID-19 related pneumomediastinum and pneumothorax and address these questions. Methods We conducted a single-center retrospective chart review of patients admitted at our institution with a positive polymerase chain reaction (PCR) confirming the diagnosis of COVID-19. A cohort of 500 potential study candidates was identified, of whom eight were investigated. Demographic data, hospital course, patient co-morbidities, and outcome data were collected. Results Eight patients were included in our study who were identified as having an event (i.e., pneumomediastinum and/or pneumothorax) during the specified timeframe. Overall, 62% of patients were on high-flow nasal cannula with an average FiO2 of >70%. The average oxygen saturation//fraction of inspired oxygen (SpO2/FiO2) ratio leading up to an event was 113.7286 (range: 101.11-130.66), and all of the patients not on mechanical ventilation met the criteria for acute respiratory distress syndrome (ARDS) based on the Kigali definition with SpO2/FiO2 < 315. The three patients who developed an event while requiring mechanical ventilation both had PaO2/FiO2 < 100, consistent with severe ARDS at the time of an event. The mean time in days, counted from the day of hospital admission until an event, was 10 days (range: 3-23 days). None of the cases had documented pulmonary parenchymal disease prior to developing COVID-19. To the best of our knowledge, these events were not iatrogenic in nature. Conclusion Secondary spontaneous pneumomediastinum and pneumothorax are rare albeit well-documented phenomena in hospitalized patients with COVID-19 infection. Interestingly, the majority of patients in our study were on high-flow nasal cannula at the time of an event. The majority of previously published data on this topic are on those who required positive pressure ventilation; however, there have been more recent papers that also describe these events in non-mechanically ventilated patients. The exact pathophysiology remains unknown, but it is likely multifactorial, and additional studies are needed to further evaluate this phenomenon.

The utility of the exoscope compared to the operating microscope in simulated temporal bone surgery.

OBJECTIVE: To objectively assess the utility of an exoscope during simulated otological surgery. DESIGN: Cohort study. SETTING: Tertiary referral otolaryngology centre. PARTICIPANTS: Seven experienced otologists undertook simulated temporal bone surgery on plastic temporal bones using the Zeiss Kinevo microscope with both a microscope and exoscope facility. OUTCOME MEASURES: The utility of microscope and exoscope was compared using a Likert scale from 1 to 10 with and without PPE. Attributes assessed included image quality, depth perception, adequacy of view, exoscope positioning, surgeon comfort, surgeon safety and adequacy of image and protection for assistants and observers. RESULTS: The exoscope in 3D mode performed as well as or better than the microscope for image quality, field of view and manoeuvrability. It outperformed the microscope for compatibility with PPE, surgeon comfort and assistant/observer experience. It scored almost as highly as the microscope for depth perception. CONCLUSION: There is likely to be a learning curve but this initial assessment of the exoscope shows significant potential as an alternative to the operating microscope in otological surgery but with the advantage of allowing the use of appropriate PPE and better ergonomics for both surgeon and assistant/observer.

Purulent pericarditis, an unusual cause of cardiac arrest.

Purulent pericarditis is a rare infection of the pericardial space defined by the presence of gross pus or microscopic purulence. Here, we present a case of Streptococcus anginosus purulent pericarditis, leading to obstructive and septic shock. After prompt pericardial drainage, the patient experienced rapid improvement in symptoms. However, due to the presence of a loculated effusion and concern for development of constrictive pericarditis, a pericardial window was performed. Although purulent pericarditis is often fatal, this case illustrates the reduced morbidity following prompt recognition and drainage.

Recurrent Metastatic Breast Cancer in Internal Mammary Lymph Nodes along the Translocated Left Internal Mammary Artery Bypass Graft.

Internal mammary lymph node (IMLN) is the second most common site for nodal metastases in breast cancer. The authors present a case of a 58-year-old woman with a history of coronary artery bypass graft surgery 1 year prior who presented with a neck mass. Imaging showed an enlarged IMLN along the course of the translocated left internal mammary artery (LIMA) bypass graft on the surface of the heart, and the patient was later proven to have recurrent breast cancer. To the authors' knowledge, this is the first case report in the literature of a breast cancer recurrence in an IMLN along the postoperative translocated LIMA bypass graft. Keywords: Adults, CT, PET/CT, Breast, Thorax, Lymphatic, Metastases © RSNA, 2021.

Patients' Experiences of Deciding Whether or Not to Accept Bone Conduction Hearing Implants: A Qualitative Investigation.

OBJECTIVES: Bone conduction hearing implants (BCHIs) are an effective option to rehabilitate hearing for people who cannot use conventional, air conduction hearing aids. However, the uptake of such devices in the United Kingdom is lower than might be expected, and the reasons for this are not fully understood. The present study used qualitative methods to explore decision-making about whether to accept or reject BCHIs. DESIGN: Semistructured telephone interviews were conducted with 17 BCHI candidates who had recently accepted or rejected BCHIs. RESULTS: A thematic analysis identified four overarching themes: participants wanted to look and feel normal; potential risks were weighed against rewards; participants felt that there was a "right time" to have a BCHI; and information from clinicians and BCHI users was treated differently. Participants' perceptions of normality were influential in the final decision, and the BHCI was seen either as a barrier or facilitator of this. Participants consistently weighed up potential advantages and disadvantages of BCHIs, with potential for hearing improvement typically used as a benchmark against which other factors were measured. Some participants who rejected BCHIs felt that they could reconsider having a BCHI when they felt the time was right for them. Participants highly valued advice from clinicians, but felt that their expertise lacked validity as clinicians typically did not have experience of using BCHIs themselves. CONCLUSIONS: The decision to accept or reject a BCHI was highly individual. Each participant considered a range of factors; the influence of each factor depended on the individual's perceptions and experiences. This work highlights the importance of clinical staff being able to explore the individual priorities and concerns of each patient to ensure that patients feel happy and confident with the decision that they make.

Early-Onset Familial Alzheimer Disease Variant PSEN2 N141I Heterozygosity is Associated with Altered Microglia Phenotype.

BACKGROUND: Early-onset familial Alzheimer disease (EOFAD) is caused by heterozygous variants in the presenilin 1 (PSEN1), presenilin 2 (PSEN2), and APP genes. Decades after their discovery, the mechanisms by which these genes cause Alzheimer's disease (AD) or promote AD progression are not fully understood. While it is established that presenilin (PS) enzymatic activity produces amyloid-ß (Aß), PSs also regulate numerous other cellular functions, some of which intersect with known pathogenic drivers of neurodegeneration. Accumulating evidence suggests that microglia, resident innate immune cells in the central nervous system, play a key role in AD neurodegeneration. OBJECTIVE: Previous work has identified a regulatory role for PS2 in microglia. We hypothesized that PSEN2 variants lead to dysregulated microglia, which could further contribute to disease acceleration. To mimic the genotype of EOFAD patients, we created a transgenic mouse expressing PSEN2 N141I on a mouse background expressing one wildtype PS2 and two PS1 alleles. RESULTS: Microglial expression of PSEN2 N141I resulted in impaired γ-secretase activity as well as exaggerated inflammatory cytokine release, NFκB activity, and Aß internalization. In vivo, PS2 N141I mice showed enhanced IL-6 and TREM2 expression in brain as well as reduced branch number and length, an indication of "activated" morphology, in the absence of inflammatory stimuli. LPS intraperitoneal injection resulted in higher inflammatory gene expression in PS2 N141I mouse brain relative to controls. CONCLUSION: Our findings demonstrate that PSEN2 N141I heterozygosity is associated with disrupted innate immune homeostasis, suggesting EOFAD variants may promote disease progression through non-neuronal cells beyond canonical dysregulated Aß production.

Online support group users' perceptions and experiences of bone-anchored hearing aids (BAHAs): a qualitative study.

Objective: Better understanding of the decision-making process for bone-anchored hearing aid (BAHA) candidates has been identified by clinicians as a research priority. This study aimed to understand experiences and perceptions of BAHA candidates and users who use online support groups.Design: One thousand posts retrieved from a public UK-based online support group were thematically analysed.Study sample: Messages were posted by 270 BAHA users and candidates.Results: Individuals used the online group to obtain information about BAHAs and support for decision-making regarding accepting BAHA surgery and wearing a percutaneous device. BAHA users evaluated the efficacy of the system, perceiving it to be highly effective in improving their hearing. The BAHA influenced individuals' self-image and impacted their social lives. Fears of surgery and post-implantation infections were regarded as challenges to be faced when choosing to accept implantation.Conclusions: BAHA candidates found the online support group useful in helping them to decide whether or not to proceed with surgery, and the personal experiences of BAHA users were predominantly positive. However, it is not clear to what extent such positive experiences are representative of BAHA users more generally, and candidates need to be aware of this when using these groups to support decision-making.

Esophageal Bronchial Artery Fistulaization: A Complication of an Endobronchial Ultrasound.

Bronchial artery pseudoaneurysms are an extremely rare cause of upper gastrointestinal bleeding. The presence of a bronchial artery pseudoaneurysm resulting in an esophageal fistula is an entity that, to our knowledge, has yet to be described. Successful management requires an interdisciplinary approach to guide closure of the defects. We present a novel case of an esophageal fistula and bronchial artery pseudoaneurysm resulting from an endobronchial ultrasound-guided transbronchial needle aspiration successfully managed by endoscopic therapy and coil embolization.

Results of a 2-Year Prospective Multicenter Study Evaluating Long-term Audiological and Clinical Outcomes of a Transcutaneous Implant for Bone Conduction Hearing.

OBJECTIVE(S): To evaluate 2-year audiological and clinical outcomes of a transcutaneous implant for bone conduction hearing of a previously published 6-month evaluation. DESIGN: Fifty-four unilaterally implanted adult patients with conductive or mild mixed hearing loss or single-sided sensorineural deafness were included in this prospective multicenter study. Follow-up visits were scheduled post-surgery at 10 days; 4, 6, and 12 weeks; 6, 12, and 24 months. Main outcomes were audiological benefit, patient-reported outcomes (PROs), soft tissue status, pain, numbness, implant survival, and daily usage. RESULTS: In the study population, the transcutaneous implant resulted in statistically significant improvement in objective hearing test and PROs compared with the unaided situation. Soft tissue complications were observed in 4.6% of the patients per visit. Pain/discomfort and numbness were initially reported in the majority of the patients, but declined over time; approximately 9% of patients reported some degree of numbness and 15% (slight) pain/discomfort after 2 years. During the 24-month period, two implant magnets were removed (3.7%), while two other implants were converted to the percutaneous counterpart (3.7%). At the final visit, 89.6% (n = 42 out of 47) of the patients used their sound processor, with a median daily usage of 6 h/d (range, 0-18 h/d). CONCLUSIONS: After 24 months, the transcutaneous implant provided statistically significant mean improvement in objective and subjective hearing performance as well as PROs compared with the preoperative unaided condition and had a low soft tissue complication rate. The test device could be considered as an alternative treatment option for appropriately selected and counseled patients.

Development and Multidisciplinary Preliminary Validation of a 3-Dimensional-Printed Pediatric Airway Model for Emergency Airway Front-of-Neck Access Procedures.

BACKGROUND: Pediatric-specific difficult airway guidelines include algorithms for 3 scenarios: unanticipated difficult tracheal intubation, difficult mask ventilation, and cannot intubate/cannot ventilate. While rare, these instances may require front-of-neck access (FONA) to secure an airway until a definitive airway can be established. The aim of this study was to develop a pediatric FONA simulator evaluated by both anesthesiology and otolaryngology providers, promoting multidisciplinary airway management. METHODS: A 3-dimensional-printed tracheal model was developed using rescaled, anatomically accurate dimensions from a computerized tomography scan using computer-aided design software. The medical grade silicone model was incorporated into a mannequin to create a low-cost, high-fidelity simulator. A multidisciplinary team of anesthesiology, otolaryngology, and simulation experts refined the model. Experts in airway management were recruited to rate the realism of the model's characteristics and features and their own ability to complete specific FONA-related tasks. RESULTS: Six expert raters (3 anesthesiology and 3 otolaryngology) were identified for multidisciplinary evaluation of model test content validity. Analysis of response data shows null variance within 1 or both specialties for a majority of the content validity tool elements. High and consistent absolute ratings for each domain indicate that the tested experts perceived this trainer as a realistic and highly valuable tool in its current state. CONCLUSIONS: The ability to practice front-of-neck emergency airway procedures safely and subsequently demonstrate proficiency on a child model has great implications regarding both quality of physician training and patient outcomes. This model may be incorporated into curricula to teach needle cricothyroidotomy and other FONA procedures to providers across disciplines.

Biophysical and physiological processes causing oxygen loss from coral reefs.

The microbialization of coral reefs predicts that microbial oxygen consumption will cause reef deoxygenation. Here we tested this hypothesis by analyzing reef microbial and primary producer oxygen metabolisms. Metagenomic data and in vitro incubations of bacteria with primary producer exudates showed that fleshy algae stimulate incomplete carbon oxidation metabolisms in heterotrophic bacteria. These metabolisms lead to increased cell sizes and abundances, resulting in bacteria consuming 10 times more oxygen than in coral incubations. Experiments probing the dissolved and gaseous oxygen with primary producers and bacteria together indicated the loss of oxygen through ebullition caused by heterogenous nucleation on algae surfaces. A model incorporating experimental production and loss rates predicted that microbes and ebullition can cause the loss of up to 67% of gross benthic oxygen production. This study indicates that microbial respiration and ebullition are increasingly relevant to reef deoxygenation as reefs become dominated by fleshy algae.

Development of a high fidelity subglottic stenosis simulator for laryngotracheal reconstruction rehearsal using 3D printing.

INTRODUCTION: Laryngotracheal reconstruction (LTR) with cartilage graft augmentation is an effective treatment for subglottic stenosis and a critical advanced procedure for Pediatric Otolaryngologists. Trainees almost exclusively learn this procedure intraoperatively on children due to the lack of adequate pediatric training models. An enhanced and accelerated educational experience may be possible if trainees can rehearse the key portions of the procedure on a simulation model. OBJECTIVE: To design and manufacture a low-cost, high fidelity surgical simulation model of subglottic stenosis for LTR. METHODS: This simulator is composed of two component models: rib cartilage and trachea. Additive manufacturing techniques, including Computer Aided Design and Three Dimensional (3D) printing, were utilized to create the simulator. Three expert Pediatric Otolaryngologists rated the functionality and realism of the simulator using Likert scale survey data. RESULTS: The use of CAD and 3D printing techniques allowed for realistic, reproducible surgical simulation of key aspects of LTR. The validation evidence indicated good to excellent means across the five domains relevant to the simulator's fidelity and usability (M = 3.47 to 4.00) out of a maximum of 4 points. Lowest rated items were consistent with expert comments suggesting minor simulator improvements. Time of production is approximately 20 h from print to post-processing, and consumable material costs per model are $2.60 USD. CONCLUSIONS: This subglottic stenosis airway simulator facilitated Laryngotracheal Reconstruction rehearsal and is a promising training tool for pediatric otolaryngologists. Our methods allow patient-specific, pre-surgical rehearsal for complex airway scenarios that could benefit the experienced airway surgeon and trainees alike. Future research aims to validate this device's utility for accelerating attainment of proficiency and improving surgical outcomes.

Audiological and clinical outcomes of a transcutaneous bone conduction hearing implant: Six-month results from a multicentre study.

OBJECTIVES: To compare the hearing performance of patients with conductive and mild mixed hearing loss and single-sided sensorineural deafness provided with a new transcutaneous bone conduction hearing implant (the Baha Attract System) with unaided hearing as well as aided with a sound processor on a softband. Furthermore, to evaluate safety and subjective benefit before and after implantation of the test device. PARTICIPANTS: Fifty-four adult patients in five participating centres were enrolled in this prospective study. Baseline data were collected during a pre-operative visit, and after a softband trial, all patients were implanted unilaterally. Follow-up visits were scheduled at 10 days, 4, 6, 12 weeks and 6 months. MAIN OUTCOME MEASURES: Free-field hearing thresholds pure-tone average (PTA4 in dB HL; mean threshold at 500, 1000, 2000, 4000 Hz; primary outcome measure). Individual free-field hearing thresholds, speech recognition in quiet and in noise, soft tissue status during follow-up and subjective benefit as measured with the Abbreviated Profile of Hearing Aid Benefit (APHAB), Speech, Spatial and Qualities of Hearing Scale (SSQ) and Health Utilities Index (HUI) questionnaires. RESULTS: Implantation of the Baha Attract System resulted in favourable audiological outcomes compared to unaided conditions. On the primary outcome parameter, a statistically significant improvement was observed compared to unaided hearing for the patients with conductive/mixed hearing loss (mean PTA4 difference -20.8 dB HL, SD 9.8; P < 0.0001) and for the patients with single-sided sensorineural deafness (SSD) (mean PTA4 difference -21.6 dB HL, SD 12.2; P < 0.0001). During all audiology tests, the non-test ear was blocked. Statistically significant improvements were also recorded in speech tests in quiet and noise compared to unaided hearing for the conductive/mixed hearing loss group and for speech in quiet in the SSD group. Compared to the pre-operative measurement with softband, no significant differences were recorded in the PTA4 free-field hearing threshold or the other audiological outcomes in either of the groups (P > 0.05). Soft tissue-related issues observed during follow-up included numbness, pain/discomfort at the implant site and to a lesser extent pressure-related skin complications. A declining trend was noted in the rate of these complications during follow-up. Approximately 20% of patients reported some degree of numbness and 38% (slight) pain/discomfort at final follow-up of 6 months. Good results on the subjective benefit questionnaires were observed, with statistically significant improvements on APHAB and SSQ questionnaires, and on the hearing attribute of HUI3. CONCLUSIONS: The Baha Attract System provided a significant improvement in hearing performance and subjective benefit compared to the pre-operative unaided condition (with the non-test ear blocked). Hearing performance of the Baha Attract was similar to a test situation with the same sound processor on a softband. A proportion of the patients reported numbness and pain/discomfort at the implant site during follow-up, especially during the first post-operative weeks. Based on the results of the current multicentre study, the Baha Attract can be considered as a treatment option for patients with the aforementioned hearing losses. Especially in the SSD patients, a careful selection procedure is warranted. Therefore, a pre-operative trial should be part of the decision-making process before fitting a patient with the Baha Attract System.

Intestinal Spirochetosis: An Obscure Cause of Lower Gastrointestinal Bleeding.

Adherence of spirochetes to the apical membrane of the colonic epithelium has been well-described in the literature, but the exact pathogenesis leading to symptomatic clinical manifestations is poorly understood. Most cases are found incidentally on the pathological evaluation of colonic biopsies taken during diagnostic or therapeutic colonoscopies. However, whether the colonization of the intestinal mucosa can be attributed to clinical symptoms is a matter of debate. Here, we present a case of intermittent hematochezia attributed to the overwhelming invasion of the colonic mucosa by intestinal spirochetes.