Effects of Melatonin on Sleep Quality and Patient-Reported Outcomes After Arthroscopic Rotator Cuff Surgery: A Prospective Randomized Controlled Trial.

BACKGROUND: Sleep disturbance is a significant symptom associated with both rotator cuff tears and arthroscopic rotator cuff repair. Melatonin has been shown to be safe and effective in managing multiple sleep disorders, including secondary sleep disorders, with relatively minor adverse effects and lack of addictive potential. PURPOSE: To investigate the effects of oral melatonin on postoperative sleep quality after arthroscopic rotator cuff repair. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: This was a prospective randomized clinical trial evaluating patients undergoing arthroscopic rotator cuff repair. Exclusion criteria included history of alcohol abuse, current antidepressant or sedative use, revision rotator cuff repair, severe glenohumeral arthritis, and concurrent adhesive capsulitis. Patients were randomly assigned in a 1:1 ratio to 1 of 2 groups: 5-mg dose of melatonin 1 hour before bedtime or standard sleep hygiene (≥6 hours per night, avoiding caffeine and naps in the evening). Patients in the melatonin group took their assigned melatonin dose for 6 weeks beginning the day of surgery. Patient-reported outcome assessments, including the Pittsburgh Sleep Quality Index (PSQI), the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), and the Single Assessment Numeric Evaluation (SANE), and pain medication charts were collected preoperatively as well as at 2 weeks, 6 weeks, 3 months, 4 months, and 6 months postoperatively. Numeric variables were analyzed using paired and unpaired t tests, with significance set at P < .05. RESULTS: Eighty patients were included for final analysis (40 in the control group, 40 in the melatonin group). Patient characteristics such as age, sex, race, body mass index, and laterality did not differ significantly (P≥ .05). Preoperative ASES, SANE, and PSQI scores did not differ between groups (P≥ .055). PSQI scores were significantly lower (better quality sleep) in the melatonin group at the 6-week postoperative period (P = .036). There was a positive correlation between how patients rated the intensity of their pain and the PSQI at the 6-week postoperative period (0.566). The PSQI question regarding sleep quality was found to be significantly lower in the melatonin group at the 3-month, 4-month, and 6-month postoperative periods (P = .015, P = .041, and P≤ .05, respectively). SANE scores were significantly lower in the melatonin group (P = .011) at 6 weeks and then higher in the melatonin group (P = .017) at 6 months. ASES scores were significantly higher in the melatonin group at 4 and 6 months (P = .022 and P = .020, respectively). Lastly, patients who were randomized into the melatonin group were found to use significantly less narcotic medication at the 4-month postoperative period (P = .046). CONCLUSION: Melatonin use after arthroscopic rotator cuff repair led to improved sleep quality (PSQI) in the early postoperative period as well as improved functional outcomes (ASES and SANE scores) and decreased narcotic use in the later postoperative period. Patients with significant sleep disturbances associated with rotator cuff repairs may benefit from the use of melatonin. REGISTRATION: NCT04278677 (ClinicalTrials.gov identifier).

A Novel Approach for the Synthesis of Responsive Core-Shell Nanogels with a Poly(N-Isopropylacrylamide) Core and a Controlled Polyamine Shell.

Microgel particles can play a key role, e.g., in drug delivery systems, tissue engineering, advanced (bio)sensors or (bio)catalysis. Amine-functionalized microgels are particularly interesting in many applications since they can provide pH responsiveness, chemical functionalities for, e.g., bioconjugation, unique binding characteristics for pollutants and interactions with cell surfaces. Since the incorporation of amine functionalities in controlled amounts with predefined architectures is still a challenge, here, we present a novel method for the synthesis of responsive core-shell nanogels (dh < 100 nm) with a poly(N-isopropylacrylamide) (pNIPAm) core and a polyamine shell. To achieve this goal, a surface-functionalized pNIPAm nanogel was first prepared in a semi-batch precipitation polymerization reaction. Surface functionalization was achieved by adding acrylic acid to the reaction mixture in the final stage of the precipitation polymerization. Under these conditions, the carboxyl functionalities were confined to the outer shell of the nanogel particles, preserving the core's temperature-responsive behavior and providing reactive functionalities on the nanogel surface. The polyamine shell was prepared by the chemical coupling of polyethyleneimine to the nanogel's carboxyl functionalities using a water-soluble carbodiimide (EDC) to facilitate the coupling reaction. The efficiency of the coupling was assessed by varying the EDC concentration and reaction temperature. The molecular weight of PEI was also varied in a wide range (Mw = 0.6 to 750 kDa), and we found that it had a profound effect on how many polyamine repeat units could be immobilized in the nanogel shell. The swelling and the electrophoretic mobility of the prepared core-shell nanogels were also studied as a function of pH and temperature, demonstrating the successful formation of the polyamine shell on the nanogel core and its effect on the nanogel characteristics. This study provides a general framework for the controlled synthesis of core-shell nanogels with tunable surface properties, which can be applied in many potential applications.

Maximum mouth opening in patients with cleft lip and palate or craniofacial anomalies compared with non-affected controls: A cross-sectional study.

BACKGROUND: There are limited published data on maximum mouth opening (MMO) for children with cleft lip or palate (CLP) or craniofacial anomalies (CFA). AIM: To report MMO of patients with CLP or CFA compared with non-affected controls. DESIGN: Retrospective cross-sectional review of electronic medical and dental records. Patients with CLP or CFA with recorded MMO, height, and weight were included and compared with a non-affected control individuals seen during orthodontic screening. Outcome measures included MMO, recorded in millimeters of inter-incisal distance, age, height, weight, and sex. RESULTS: Patients with CLP or CFA (n = 376) were matched by age and body mass standardized index (BMIz) to the non-affected pool (n = 376). The affected group had a MMO of 43.14 mm (±7.1 mm) compared with the control group MMO of 48.01 mm (±7.6 mm) with a statistically significant difference of -4.86 mm (p < .0001). Specifically, MMO of the unilateral cleft group is 4.26 mm smaller than that of non-affected controls (p < .0001). MMO of the bilateral cleft group is 3.65 mm smaller than that of non-affected controls (p = 0.0063). CONCLUSIONS: MMO for patients with CLP was significantly smaller as compared to non-affected controls. This study helps establish MMO values for children with CLP and CFA.

Alterations of cerebrovascular reactivity following pediatric mild traumatic brain injury are independent of neurodevelopmental changes.

Cerebrovascular dysfunction following mild traumatic brain injury (mTBI) is understudied relative to other microstructural injuries, especially during neurodevelopment. The blood-oxygen level dependent response was used to investigate cerebrovascular reactivity (CVR) in response to hypercapnia following pediatric mTBI (pmTBI; ages 8-18 years), as well as pseudocontinuous arterial spin labeling to measure cerebral blood flow (CBF). Data were collected ∼1-week (N = 107) and 4 months (N = 73) post-injury. Sex- and age-matched healthy controls (HC) underwent identical examinations at comparable time points (N = 110 and N = 91). Subtle clinical and cognitive deficits existed at ∼1 week that resolved for some, but not all domains at 4 months post-injury. At both visits, pmTBI showed an increased maximal fit between end-tidal CO2 regressor and the cerebrovascular response across multiple regions (primarily fronto-temporal), as well as increased latency to maximal fit in independent regions (primarily posterior). Hypoperfusion was also noted within the bilateral cerebellum. A biphasic relationship existed between CVR amplitude and age (i.e., positive until 14.5 years, negative thereafter) in both gray and white matter, but these neurodevelopment effects did not moderate injury effects. CVR metrics were not associated with post-concussive symptoms or cognitive deficits. In conclusion, cerebrovascular dysfunction may persist for up to four months following pmTBI.

Curve progression following selective and nonselective spinal fusion for adolescent idiopathic scoliosis: are selective fusions stable?

PURPOSE: The purpose of this study is to compare postoperative outcomes between selective and non-selective fusions longitudinally over the first five postoperative years. METHODS: Patient parameters were retrieved from a multicenter, prospective, database. Patients with Lenke 1-6, B and C deformities were included. Patients were stratified into 2 groups: selective fusion (SF), if the last instrumented vertebra (LIV) was at or cranial to the lumbar apex, or non-selective fusion (NSF). Differences in coronal and sagittal radiographic outcomes were assessed with generalized linear models (GLMs) at 1-, 2- and 5- year postoperative outcomes. Five-year postoperative categorical radiographic outcomes, flexibility, scoliosis research society scores (SRS), and reoperation rates were compared between groups. Matched cohorts were created for subgroup analysis. RESULTS: 416 (SF:261, NF:155) patients, including 353 females were included in this study. The mean preoperative thoracic and lumbar Cobb angles were 57.3 ± 8.9 and 45.3 ± 8.0, respectively. GLMs demonstrated greater postoperative coronal deformity in the SF group (p < 0.01); however, the difference between groups did not change overtime (p > 0.05) indicating a relatively stable postoperative deformity correction. The SF group had a greater incidence of lumbar Cobb ≥ 26 degrees (p < 0.01). The NSF group demonstrated worse forward and lateral flexibility at 5-year postoperative outcome (p < 0.05). There was no difference in postoperative SRS scores between the SF and NSF groups. Reoperation rates were similar between groups. CONCLUSION: Selective fusion results in greater coronal plane deformity; however, this deformity does not progress significantly over time compared to non-selective fusion. Selective spinal fusion may be a beneficial option for a larger subset of patients than previously identified. LEVEL OF EVIDENCE: III.

Predictors of Patient-Reported Outcomes After Hyaluronic Acid Injections: Effect of Expectations and Psychological Stress.

INTRODUCTION: Hyaluronic acid (HA) injections are a common nonsurgical treatment of knee osteoarthritis (OA). Patient expectations and psychological stress are believed to affect outcomes after orthopaedic procedures. METHODS: This was a prospective cohort study seeking to identify factors predictive of greater patient-reported outcomes after HA injections, particularly expectations and psychological stress. 250 patients receiving a series of HA injections for knee OA were enrolled, with 196 being included for analysis. Demographics, surgical history, and preoperative Kellgren-Lawrence severity scores were collected, and patients completed the Knee Osteoarthritis Outcome Score (KOOS) questionnaire, a modified KOOS questionnaire assessing their 6-month postinjection expectations, and the Perceived Stress Scale before the first injection. Outcomes were assessed at 3 weeks and 3 and 6 months after the final injection. RESULTS: KOOS scores improved from preinjection to 6-month follow-up but did not meet patients' expectations or minimal clinically important difference. Expectations correlated with 6-month KOOS pain, activities of daily living, sport, and quality of life subscales (ρ = 0.19 to 0.34), but not the symptom subscale (P = 0.10). Expectations (ρ = 0.31 to 0.37), younger age (ρ = -0.17 to -0.18), and greater perceived stress (ρ = 0.23) correlated with greater improvement from baseline KOOSs. Lower body mass index (ρ = -0.19 to -0.22), male sex (ρ = -0.17), and greater preinjection function (ρ = 0.37 to 0.46) correlated with greater 6-month outcomes. Stress measured on the Perceived Stress Scale did not correlate with 6-month KOOSs (P ≥ 0.27). Lower Kellgren-Lawrence severity score was weakly associated with greater 6-month KOOS activities of daily living and sport scores (ρ = -0.15 to -0.16) and greater improvement in the KOOS symptom score (ρ = -0.15). DISCUSSION: This study identified that higher expectations, lower body mass index, younger age, male sex, lower radiographic severity, greater preinjection function, and greater perceived stress are associated with greater patient outcomes after HA injection. Physicians should consider these factors when counseling patients with knee OA about viscosupplementation. STUDY TYPE: Prospective Cohort Study (Level of Evidence II).

Photoresponsive arylazopyrazole surfactant/PDADMAC mixtures: reversible control of bulk and interfacial properties.

In many applications of polyelectrolyte/surfactant (P/S) mixtures, it is difficult to fine-tune them after mixing the components without changing the sample composition, e.g. pH or the ionic strength. Here we report on a new approach where we use photoswitchable surfactants to enable drastic changes in both the bulk and interfacial properties. Poly(diallyldimethylammonium chloride) (PDADMAC) mixtures with three alkyl-arylazopyrazole butyl sulfonates (CnAAP) with -H, -butyl and -octyl tails are applied and E/Z photoisomerization of the surfactants is used to cause substantially different hydrophobic interactions between the surfactants and PDADMAC. These remotely controlled changes affect significantly the P/S binding and allows for tuning both the bulk and interfacial properties of PDADMAC/CnAAP mixtures through light irradiation. For that, we have fixed the surfactant concentrations at values where they exhibit pronounced surface tension changes upon E/Z photoisomerization with 365 nm UV light (Z) and 520 nm green (E) light and have varied the PDADMAC concentration. The electrophoretic mobility can be largely tuned by photoisomerisation of CnAAP surfactants and P/S aggregates, which can even exhibit a charge reversal from negative to positive values or vice versa. In addition, low colloidal stability at equimolar concentrations of PDADMAC with CnAAP surfactants in the E configuration lead to the formation of large aggregates in the bulk which can be broken up by irradiation with UV light when the surfactant's alkyl chain is short enough (C0AAP). Vibrational sum-frequency generation (SFG) spectroscopy reveals changes at the interface similar to the bulk, where the charging state at air-water interfaces can be modified with light irradiation. Using SFG spectroscopy, we interrogated the O-H stretching modes of interfacial H2O and provide qualitative information on surface charging that is complemented by neutron reflectometry, from which we resolved the surface excesses of PDADMAC and CnAAP at the air-water interface, independently.

Exploring proteins at soft interfaces and in thin liquid films - From classical methods to advanced applications of reflectometry.

The history of the topic of proteins at soft interfaces dates back to the 19th century, and until the present day, it has continuously attracted great scientific interest. A multitude of experimental methods and theoretical approaches have been developed to serve the research progress in this large domain of colloid and interface science, including the area of soft colloids such as foams and emulsions. From classical methods like surface tension adsorption isotherms, surface pressure-area measurements for spread layers, and surface rheology probing the dynamics of adsorption, nowadays, advanced surface-sensitive techniques based on spectroscopy, microscopy, and the reflection of light, X-rays and neutrons at liquid/fluid interfaces offers important complementary sources of information. Apart from the fundamental characteristics of protein adsorption layers, i.e., surface tension and surface excess, the nanoscale structure of such layers and the interfacial protein conformations and morphologies are of pivotal importance for extending the depth of understanding on the topic. In this review article, we provide an extensive overview of the application of three methods, namely, ellipsometry, X-ray reflectometry and neutron reflectometry, for adsorption and structural studies on proteins at water/air and water/oil interfaces. The main attention is placed on the development of experimental approaches and on a discussion of the relevant achievements in terms of notable experimental results. We have attempted to cover the whole history of protein studies with these techniques, and thus, we believe the review should serve as a valuable reference to fuel ideas for a wide spectrum of researchers in different scientific fields where proteins at soft interface may be of relevance.

Translational use of homing peptides: Tumor and placental targeting.

HYPOTHESIS: Tissue-specific homing peptides have been shown to improve chemotherapeutic efficacy due to their trophism for tumor cells. Other sequences that selectively home to the placenta are providing new and safer therapeutics to treat complications in pregnancy. Our hypothesis is that the placental homing peptide RSGVAKS (RSG) may have binding affinity to cancer cells, and that insight can be gained into the binding mechanisms of RSG and the tumor homing peptide CGKRK to model membranes that mimic the primary lipid compositions of the respective cells. EXPERIMENTS: Following cell culture studies on the binding efficacy of the peptides on a breast cancer cell line, a systematic translational characterization is delivered using ellipsometry, Brewster angle microscopy and neutron reflectometry of the extents, structures, and dynamics of the interactions of the peptides with the model membranes on a Langmuir trough. FINDINGS: We start by revealing that RSG does indeed have binding affinity to breast cancer cells. The peptide is then shown to exhibit stronger interactions and greater penetration than CGKRK into both model membranes, combined with greater disruption to the lipid component. RSG also forms aggregates bound to the model membranes, yet both peptides bind to a greater extent to the placental than cancer model membranes. The results demonstrate the potential for varying local reservoirs of peptide within cell membranes that may influence receptor binding. The innovative nature of our findings motivates the urgent need for more studies involving multifaceted experimental platforms to explore the use of specific peptide sequences to home to different cellular targets.

Dynamic Functional Connectivity in Pediatric Mild Traumatic Brain Injury.

Resting-state fMRI can be used to identify recurrent oscillatory patterns of functional connectivity within the human brain, also known as dynamic brain states. Alterations in dynamic brain states are highly likely to occur following pediatric mild traumatic brain injury (pmTBI) due to the active developmental changes. The current study used resting-state fMRI to investigate dynamic brain states in 200 patients with pmTBI (ages 8-18 years, median = 14 years) at the subacute (∼1-week post-injury) and early chronic (∼ 4 months post-injury) stages, and in 179 age- and sex-matched healthy controls (HC). A k-means clustering analysis was applied to the dominant time-varying phase coherence patterns to obtain dynamic brain states. In addition, correlations between brain signals were computed as measures of static functional connectivity. Dynamic connectivity analyses showed that patients with pmTBI spend less time in a frontotemporal default mode/limbic brain state, with no evidence of change as a function of recovery post-injury. Consistent with models showing traumatic strain convergence in deep grey matter and midline regions, static interhemispheric connectivity was affected between the left and right precuneus and thalamus, and between the right supplementary motor area and contralateral cerebellum. Changes in static or dynamic connectivity were not related to symptom burden or injury severity measures, such as loss of consciousness and post-traumatic amnesia. In aggregate, our study shows that brain dynamics are altered up to 4 months after pmTBI, in brain areas that are known to be vulnerable to TBI. Future longitudinal studies are warranted to examine the significance of our findings in terms of long-term neurodevelopment.

Sex- and Age-Related Differences in Post-Concussive Symptom Reporting Among Children and Their Parents.

Pediatric mild traumatic brain injury (pmTBI) has received increased public attention over the past decade, especially for children who experience persistent post-concussive symptoms (PCS). Common methods for obtaining pediatric PCS rely on both self- and parental report, exhibit moderate test-retest reliability, and variable child-parent agreement, and may yield high false positives. The current study investigated the impact of age and biological sex on PCS reporting (Post-Concussion Symptom Inventory) in patients with pmTBI (n = 286) at retrospective, 1 week, 4 months, and 1 year post-injury time points, as well as reported symptoms in healthy controls (HC; n = 218) at equivalent assessment times. HC and their parents reported higher PCS for their retrospective rating relative to the other three other study visits. Child-parent agreement was highest for female adolescents, but only approached acceptable ranges (≥ 0.75) immediately post-injury. Poor-to-fair child/parental agreement was observed for most other study visits for pmTBI and at all visits for HC. Parents rated female adolescents as being more symptomatic than their male counterparts in spite of small (pmTBI) or no (HC) sex-related differences in self-reported ratings, suggestive of a potential cultural bias in parental ratings. Test-retest reliability for self-report was typically below acceptable ranges for both pmTBI and HC groups, with reliability decreasing for HC and increasing for pmTBI as a function of time between visits. Parental test-retest reliability was higher for females. Although continued research is needed, current results support the use of child self-report over parental ratings for estimating PCS burden. Results also highlight the perils of relying on symptom self-report for diagnostic and prognostic purposes.

Cognition and post-concussive symptom status after pediatric mild traumatic brain injury.

Cognitive impairment and post-concussive symptoms (PCS) represent hallmark sequelae of pediatric mild traumatic brain injury (pmTBI). Few studies have directly compared cognition as a function of PCS status longitudinally. Cognitive outcomes were therefore compared for asymptomatic pmTBI, symptomatic pmTBI, and healthy controls (HC) during sub-acute (SA; 1-11 days) and early chronic (EC; approximately 4 months) post-injury phases. We predicted worse cognitive performance for both pmTBI groups relative to HC at the SA visit. At the EC visit, we predicted continued impairment from the symptomatic group, but no difference between asymptomatic pmTBI and HCs. A battery of clinical (semi-structured interviews and self-report questionnaires) and neuropsychological measures were administered to 203 pmTBI and 139 HC participants, with greater than 80% retention at the EC visit. A standardized change method classified pmTBI into binary categories of asymptomatic or symptomatic based on PCS scores. Symptomatic pmTBI performed significantly worse than HCs on processing speed, attention, and verbal memory at SA visit, whereas lower performance was only present for verbal memory for asymptomatic pmTBI. Lower performance in verbal memory persisted for both pmTBI groups at the EC visit. Surprisingly, a minority (16%) of pmTBI switched from asymptomatic to symptomatic status at the EC visit. Current findings suggest that PCS and cognition are more closely coupled during the first week of injury but become decoupled several months post-injury. Evidence of lower performance in verbal memory for both asymptomatic and symptomatic pmTBI suggests that cognitive recovery may be a process separate from the resolution of subjective symptomology.

Multifaceted neural and vascular pathologies after pediatric mild traumatic brain injury.

Dynamic changes in neurodevelopment and cognitive functioning occur during adolescence, including a switch from reactive to more proactive forms of cognitive control, including response inhibition. Pediatric mild traumatic brain injury (pmTBI) affects these cognitions immediately post-injury, but the role of vascular versus neural injury in cognitive dysfunction remains debated. This study consecutively recruited 214 sub-acute pmTBI (8-18 years) and age/sex-matched healthy controls (HC; N = 186), with high retention rates (>80%) at four months post-injury. Multimodal imaging (functional MRI during response inhibition, cerebral blood flow and cerebrovascular reactivity) assessed for pathologies within the neurovascular unit. Patients exhibited increased errors of commission and hypoactivation of motor circuitry during processing of probes. Evidence of increased/delayed cerebrovascular reactivity within motor circuitry during hypercapnia was present along with normal perfusion. Neither age-at-injury nor post-concussive symptom load were strongly associated with imaging abnormalities. Collectively, mild cognitive impairments and clinical symptoms may continue up to four months post-injury. Prolonged dysfunction within the neurovascular unit was observed during proactive response inhibition, with preliminary evidence that neural and pure vascular trauma are statistically independent. These findings suggest pmTBI is characterized by multifaceted pathologies during the sub-acute injury stage that persist several months post-injury.

Efficient approach to computing travel time with the parabolic equation model.

An efficient method for computing the travel time of an acoustic wave using the parabolic equation model is presented. The frequency derivative of the acoustic phase is the differential travel time associated with a propagation in range. By taking this difference across closely spaced frequencies this method computes the acoustic travel time. This method requires the computation of the field at two frequencies rather than over the full band. The method compares well with other travel time methods for four different cases, including deep water, upslope and shallow water, and a three-dimensional propagation environment.

Effects of Charge Density on Spread Hyperbranched Polyelectrolyte/Surfactant Films at the Air/Water Interface.

The interfacial structure and morphology of films spread from hyperbranched polyethylene imine/sodium dodecyl sulfate (PEI/SDS) aggregates at the air/water interface have been resolved for the first time with respect to polyelectrolyte charged density. A recently developed method to form efficient films from the dissociation of aggregates using a minimal quantity of materials is exploited as a step forward in enhancing understanding of the film properties with a view to their future use in technological applications. Interfacial techniques that resolve different time and length scales, namely, ellipsometry, Brewster angle microscopy, and neutron reflectometry, are used. Extended structures of both components are formed under a monolayer of the surfactant with bound polyelectrolytes upon film compression on subphases adjusted to pH 4 or 10, corresponding to high and low charge density of the polyelectrolyte, respectively. A rigid film is related to compact conformation of the PEI in the interfacial structure at pH 4, while it is observed that aggregates remain embedded in mobile films at pH 10. The ability to compact surfactants in the monolayer to the same extent as its maximum coverage in the absence of polyelectrolyte is distinct from the behavior observed for spread films involving linear polyelectrolytes, and intriguingly evidence points to the formation of extended structures over the full range of surface pressures. We conclude that the molecular architecture and charge density can be important parameters in controlling the structures and properties of spread polyelectrolyte/surfactant films, which holds relevance to a range of applications, such as those where PEI is used, including CO2 capture, electronic devices, and gene transfection.

Aqueous Radical Initiated Oxidation of an Organic Monolayer at the Air-Water Interface as a Proxy for Thin Films on Atmospheric Aerosol Studied with Neutron Reflectometry.

Neutron reflectometry has been used to study the radical initiated oxidation of a monolayer of the lipid 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) at the air-solution interface by aqueous-phase hydroxyl, sulfate, and nitrate radicals. The oxidation of organic films at the surface of atmospheric aqueous aerosols can influence the optical properties of the aerosol and consequently can impact Earth's radiative balance and contribute to modern climate change. The amount of material at the air-solution interface was found to decrease on exposure to aqueous-phase radicals which was consistent with a multistep degradation mechanism, i.e., the products of reaction of the DSPC film with aqueous radicals were also surface active. The multistep degradation mechanism suggests that lipid molecules in the thin film degrade to form progressively shorter chain surface active products and several reactive steps are required to remove the film from the air-solution interface. Bimolecular rate constants for oxidation via the aqueous phase OH radical cluster around 1010 dm3 mol-1 s-1. Calculations to determine the film lifetime indicate that it will take ∼4-5 days for the film to degrade to 50% of its initial amount in the atmosphere, and therefore attack by aqueous radicals on organic films could be atmospherically important relative to typical atmospheric aerosol lifetimes.

Neural correlates of cognitive control deficits in pediatric mild traumatic brain injury.

There is a growing body of research showing that cerebral pathophysiological processes triggered by pediatric mild traumatic brain injury (pmTBI) may extend beyond the usual clinical recovery timeline. It is paramount to further unravel these processes, because the possible long-term cognitive effects resulting from ongoing secondary injury in the developing brain are not known. In the current fMRI study, neural processes related to cognitive control were studied in 181 patients with pmTBI at sub-acute (SA; ~1 week) and early chronic (EC; ~4 months) stages post-injury. Additionally, a group of 162 age- and sex-matched healthy controls (HC) were recruited at equivalent time points. Proactive (post-cue) and reactive (post-probe) cognitive control were examined using a multimodal attention fMRI paradigm for either congruent or incongruent stimuli. To study brain network function, the triple-network model was used, consisting of the executive and salience networks (collectively known as the cognitive control network), and the default mode network. Additionally, whole-brain voxel-wise analyses were performed. Decreased deactivation was found within the default mode network at the EC stage following pmTBI during both proactive and reactive control. Voxel-wise analyses revealed sub-acute hypoactivation of a frontal area of the cognitive control network (left pre-supplementary motor area) during proactive control, with a reversed effect at the EC stage after pmTBI. Similar effects were observed in areas outside of the triple-network during reactive control. Group differences in activation during proactive control were limited to the visual domain, whereas for reactive control findings were more pronounced during the attendance of auditory stimuli. No significant correlations were present between task-related activations and (persistent) post-concussive symptoms. In aggregate, current results show alterations in neural functioning during cognitive control in pmTBI up to 4 months post-injury, regardless of clinical recovery. We propose that subacute decreases in activity reflect a general state of hypo-excitability due to the injury, while early chronic hyperactivation represents a compensatory mechanism to prevent default mode interference and to retain cognitive control.

Acute respiratory distress syndrome: potential of therapeutic interventions effective in treating progression from COVID-19 to treat progression from other illnesses-a systematic review.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is the most severe form of lung injury, rendering gaseous exchange insufficient, leading to respiratory failure. Despite over 50 years of research on the treatment of ARDS when developed from illnesses such as sepsis and pneumonia, mortality remains high, and no robust pharmacological treatments exist. The progression of SARS-CoV-2 infections to ARDS during the recent global pandemic led to a surge in the number of clinical trials on the condition. Understandably, this explosion in new research focused on COVID-19 ARDS (CARDS) rather than ARDS when developed from other illnesses, yet differences in pathology between the two conditions mean that optimal treatment for them may be distinct. AIM: The aim of the present work is to assess whether new therapeutic interventions that have been developed for the treatment of CARDS may also hold strong potential in the treatment of ARDS when developed from other illnesses. The study objectives are achieved through a systematic review of clinical trials. RESULTS: The COVID-19 pandemic led to the identification of various therapeutic interventions for CARDS, some but not all of which are optimal for the management of ARDS. Interventions more suited to CARDS pathology include antithrombotics and biologic agents, such as cytokine inhibitors. Cell-based therapies, on the other hand, show promise in the treatment of both conditions, attributed to their broad mechanisms of action and the overlap in the clinical manifestations of the conditions. A shift towards personalised treatments for both CARDS and ARDS, as reflected through the increasing use of biologics, is also evident. CONCLUSIONS: As ongoing CARDS clinical trials progress, their findings are likely to have important implications that alter the management of ARDS in patients that develop the condition from illnesses other than COVID-19 in the future.

Effects of anodal tDCS on electroencephalography correlates of cognitive control in mild-to-moderate traumatic brain injury.

BACKGROUND: Transcranial direct current stimulation (tDCS) may provide a potential therapy for cognitive deficits caused by traumatic brain injury (TBI), yet its efficacy and mechanisms of action are still uncertain. OBJECTIVE: We hypothesized that anodal tDCS over the left dorsolateral prefrontal cortex (DLPFC) would boost the influence of a cognitive training regimen in a mild-to-moderate TBI (mmTBI) sample. Cognitive enhancement was measured by examining event-related potentials (ERPs) during cognitive control tasks from pre- to post-treatment. METHODS: Thirty-four participants with mmTBI underwent ten sessions of cognitive training with active (n = 17) or sham (n = 17) anodal tDCS to the left DLPFC. ERPs were assessed during performance of an auditory oddball (3AOB), N-back, and dot pattern expectancy (DPX) task before and after treatment. RESULTS: P3b amplitudes significantly decreased from baseline to post-treatment testing, regardless of tDCS condition, in the N-back task. The active tDCS group demonstrated a significantly increased P3a amplitude in the DPX task. No statistically significant stimulation effects were seen during the 3AOB and N-back tasks. CONCLUSION: Active anodal tDCS paired with cognitive training led to increases in P3a amplitudes in the DPX, inferring increased cognitive control. P3b decreased in the N-back task demonstrating the effects of cognitive training. These dissociated P3 findings suggest separate mechanisms invoked by different neuroplasticity-inducing paradigms (stimulation versus training) in brain networks that support executive functioning.

Control of the structure and morphology of polypeptide/surfactant spread films by exploiting specific interactions.

We demonstrate control of the structure and morphology of polypeptide/surfactant films at the air/water interface as a function of the maximum compression ratio of the surface area, exploiting a recently developed film formation mechanism that requires minimal quantities of materials involving the dissociation of aggregates. The systems studied are poly(L-lysine) (PLL) or poly(L-arginine) (PLA) with sodium dodecyl sulfate (SDS), chosen because the surfactant (i) interacts more strongly with the latter polypeptide due to the formation of hydrogen bonds between the guanidinium group and its oxygen atoms, and (ii) induces bulk ß-sheet and α-helix conformations of the respective polypeptides. The working hypothesis is that such different interactions may be used to tune the film properties when compressed to form extended structures (ESs). Neutron reflectometry reveals that application of a high compression ratio (4.5 : 1) results in the nanoscale self-assembly of ESs containing up to two PLL-wrapped SDS bilayers. Brewster angle microscopy provides images of the PLL/SDS ESs as discrete regions on the micrometre scale while additional linear regions of PLA/SDS ESs mark macroscopic film folding. Ellipsometry demonstrates high stability of the different ESs formed. The collapse of PLL/SDS films upon compression to a very high ratio (10 : 1) is irreversible due to the formation of solid domains that remain embedded in the film upon expansion while that of PLA/SDS films is reversible. These findings demonstrate that differences in the side group of a polypeptide can have a major influence on controlling the film properties, marking a key step in the development of this new film formation mechanism for the design of biocompatible and/or biodegradable films with tailored properties for applications in tissue engineering, biosensors and antimicrobial coatings.