Pulse Pressure Variance (PPV)-Guided Fluid Management in Adult Patients Undergoing Supratentorial Tumor Surgeries: A Randomized Controlled Trial.

Objective Appropriate fluid management in neurosurgery is critical due to the risk of secondary brain injury. Determination of volume status is challenging with static variables being unreliable. Goal-directed fluid therapy with dynamic variables allows reliable determination of fluid responsiveness and promises better outcomes. We aimed to compare the intraoperative fluid requirement between conventional central venous pressure (CVP)-guided and pulse pressure variance (PPV)-guided fluid management in supratentorial tumor surgeries. Materials and Methods This prospective, randomized, double-blind, single-center trial was conducted with 72 adults undergoing supratentorial tumor surgery in a supine position. Patients were divided into two groups of 36 patients each receiving CVP- and PPV-guided fluid therapy. The CVP-guided group received boluses to target CVP greater than 8 mm Hg along with hourly replacement of intraoperative losses and maintenance fluids. The PPV-guided group received boluses to target PPV less than 13% in addition to maintenance fluids. Total intraoperative fluids administered and the incidence of hypotension was recorded along with the brain relaxation score. Postoperatively, serum lactate levels, periorbital and conjunctival edema, as well as postoperative nausea and vomiting were assessed. Statistical Analyses All statistical analyses were performed with Statistical Package for Social Sciences, version-20 (SPSS-20, IBM, Chicago, Illinois, United States). To compare the means between the two groups (CVP vs. PPV), independent samples t -test was used for normal distribution data and Mann-Whitney U test for nonnormal distribution data. The chi-square test or Fischer's exact test was used for categorical variables. Results The CVP group received significantly more intraoperative fluids than the PPV group (4,340 ± 1,010 vs. 3,540 ± 740 mL, p < 0.01). Incidence of hypotension was lower in the PPV group (4 [11.1%] vs. 0 [0%], p = 0.04). Brain relaxation scores, serum lactate levels, periorbital and conjunctival edema, and incidence of postoperative nausea and vomiting were comparable between the groups. Conclusion The requirement for intraoperative fluids was less in PPV-guided fluid management with better hemodynamic stability, adequate brain conditions, and no compromise of perfusion.

Sunburst quantum Ising model under interaction quench: Entanglement and role of initial state coherence.

We study the nonequilibrium dynamics of an isolated bipartite quantum system, the sunburst quantum Ising model, under interaction quench. The prequench limit of this model is two noninteracting integrable systems, namely a transverse Ising chain and finite number of isolated qubits. As a function of interaction strength, the spectral fluctuation property goes from Poisson to Wigner-Dyson statistics. We chose entanglement entropy as a probe to study the approach to thermalization or lack of it in postquench dynamics. In the near-integrable limit, as expected, the linear entropy displays oscillatory behavior, while in the chaotic limit it saturates. Along with the chaotic nature of the time evolution generator, we show the importance of the role played by the coherence of the initial state in deciding the nature of thermalization. We further show that these findings are general by replacing the Ising ring with a disordered XXZ model with disorder strength putting it in the many-body localized phase.

Evaluation of the Role of Preoperative Oral Amisulpride as Part of a Multimodal Antiemetic Prophylaxis Regime on Postoperative Nausea and Vomiting in Patients Undergoing Craniotomy: A Prospective, Double-Blind, Randomized, Placebo-controlled Study.

BACKGROUND: Patients undergoing craniotomy are at high risk for postoperative nausea and vomiting (PONV) despite the use of prophylactic antiemetics. We hypothesized that a single preoperative oral dose of amisulpride as part of a multimodal antiemetic regimen would decrease the incidence of PONV in patients undergoing craniotomy for intracranial tumor surgery. METHODS: Adult patients scheduled for elective craniotomy requiring general anesthesia were enrolled and randomized to receive either oral amisulpride 25 mg or placebo 2 hours before surgery in addition to our institution's usual antiemetic regimen. The primary outcome of the study was the incidence of nausea and/or vomiting during the first 24 hours postoperatively. Secondary outcomes included severity of nausea, use of rescue antiemetic medications, and treatment-related adverse events. RESULTS: A total of 100 patients were included in the analysis. More patients in the amisulpride group had no episodes of nausea (90% vs. 40%; P<0.001) and no episodes of vomiting (94% vs. 46%; P<0.001) compared with the placebo group. The severity of nausea was lower in the amisulpride group than in the control group in the first 4 hours after surgery (P<0.05), and fewer patients receiving amisulpride required rescue antiemetics (P<0.001). The incidence of treatment-related adverse events was similar between groups. CONCLUSIONS: A single preoperative oral dose of amisulpride 25 mg as a component of a multimodal antiemetic regimen decreased the incidence and severity of PONV in patients undergoing craniotomy for intracranial tumor surgery, with no adverse effects.

Evaluation of the GCS-Pupils Score for PrOgnosis in trauMatic brAin injury- The COMA Study.

OBJECTIVES: Glasgow Coma Scale-Pupils (GCS-P) score has been found to be strongly related to in-hospital mortality in retrospective studies. We hypothesized that GCS-P would be better prognosticator than Glasgow Coma Scale (GCS) in patients with traumatic brain injury (TBI). METHODS: In this prospective, multicentric, observational study, GCS and GCS-P scores were noted in adult TBI patients at ICU admission. Demographic variables, relevant clinical history, clinical/radiological findings and ICU complications were also noted. Extended Glasgow Outcome scale was noted at hospital discharge and at 6 months post-injury. Logistic regression analysis was carried out to estimate the odds for poor outcome adjusted for covariates. Sensitivity, specificity, area under curve (AUC) and odds ratio are reported for poor outcome at estimated cutoff point. RESULTS: A total of 573 patients were included in this study. The predictive power for mortality, shown by the AUC, was 0.81 [95% CI: 0.77-0.85] for GCS and 0.81 [95% CI: 0.77-0.86] for GCS-P score, both being comparable. Similarly, the predictive ability for outcome at discharge and 6 months, the AUC-ROC for both GCS and GCS-P were comparable. CONCLUSIONS: GCS-P is a good predictor of mortality and poor outcome. However, the predictive performance of GCS and GCS-P for in-hospital mortality and functional outcome at discharge and at 6 months remains comparable.

Quantum coherence controls the nature of equilibration and thermalization in coupled chaotic systems.

A bipartite system whose subsystems are fully quantum chaotic and coupled by a perturbative interaction with a tunable strength is a paradigmatic model for investigating how isolated quantum systems relax toward an equilibrium. It is found that quantum coherence of the initial product states in the energy eigenbasis of the subsystems-quantified by the off-diagonal elements of the subsystem density matrices-can be viewed as a resource for equilibration and thermalization as manifested by the entanglement generated. Results are given for four distinct perturbation strength regimes, the ultraweak, weak, intermediate, and strong regimes. For each, three types of tensor product states are considered for the initial state: uniform superpositions, random superpositions, and individual subsystem eigenstates. A universal timescale is identified involving the interaction strength parameter. In particular, maximally coherent initial product states (a form of uniform superpositions) thermalize under time evolution for any perturbation strength in spite of the fact that in the ultraweak perturbative regime the underlying eigenstates of the system have a tensor product structure and are not at all thermal-like; though the time taken to thermalize tends to infinity as the interaction vanishes. Moreover, it is shown that in the ultraweak regime the initial entanglement growth of the system whose initial states are maximally coherent is quadratic-in-time, in contrast to the widely observed linear behavior.

Comparison of Cardiac Indices Using Two Different Concentrations of Topical Adrenaline during Endoscopic Transsphenoidal Pituitary Surgery: A Prospective Randomized Observational Study.

Introduction Adrenaline-soaked wicks are often employed to decongest nasal mucosa during transsphenoidal pituitary surgeries to ensure proper hemostasis and visibility of the operating field. Considerable debate exists regarding the optimum concentration of adrenaline that strikes a balance between hemostasis as well as the hemodynamic side effects of adrenaline. This study assessed cardiac indices like cardiac output and cardiac index using a FloTrac Vigileo cardiac output monitor to compare two different concentrations of adrenaline used for topical instillation. Materials and Methods 60 adult patients undergoing transsphenoidal pituitary surgery were randomly assigned to receive cotton wicks soaked in adrenaline solution (either 1:100,000 or 1:200,000) for nasal decongestion. Following a standardized anesthetic regime, a FloTrac Vigileo cardiac output monitor was attached with the invasive arterial line for precise monitoring and recording of cardiac indices (cardiac output and cardiac index). Additionally, quality of surgical field (as reported by the operating surgeon) blood loss, incidences of adverse hemodynamic events, and rescue drug usage were recorded. Results No difference in cardiac outputs and cardiac indexes of the patients was observed during baseline to 55 minutes and at 80 minutes and onward, whereas difference rose to statistical significance at the time points of 60 minutes and 70 minutes ( p < 0.05). Other parameters like stroke volume, stroke volume variation, and hemodynamic parameters were similar. Quality of the surgical fields (as reported by the surgeon), intraoperative bleeding, incidences of adverse effects, and frequency of rescue drugs usage were similar. Conclusion Instillation of 1:100,000 dilution of adrenaline solution compared with 1:200,000 for nasal decongestion is associated with significant rise in cardiac output and cardiac index at 60 and 70 minutes of the surgery with similar blood loss and hemodynamic variables. Therefore, the lower concentration of adrenaline can be recommended for usage during transsphenoidal pituitary surgeries.

Impact of Postoperative ABG Analysis and ICU Weaning Protocol in Surgical Outcome of Atlanto-Axial Dislocation: It's not the Towering Sail, but the Unseen Wind that Moves the Ship.

Background: The outcome in patients of atlanto-axial dislocation (AAD) depends on multiple factors like preoperative optimization, intraoperative distractio and cord manipulation. Certain unfocussed factors such as respiratory reserve and compensatory acclimatization to hypoxia warrant consideration. Aims: The purpose of this study is to find the association of postoperative arterial blood gas (ABG) analysis and respiratory reserve in patients of AAD with clinical outcome. Study Design: We retrospectively analyzed the available records of patients, operated for AAD, at our institute (n = 66), from January 2014 to November 2018. Materials and Methods: Preoperative pulmonary function test (PFT) and the postoperative ABG analysis was noted. Timing of extubation, duration of intensive care unit (ICU) stays, and clinical outcomes (Nurick grade) were noted from the inpatient record and the last outpatient follow up. An independent t-test and analysis of variance were used to find significance. Results: In total, 41% (n = 27) patients had body mass index of less than 18.5, and 50% (n = 33) had breath holding time of less than 20 minutes. There was improvement in mean Nurick grade from 3.17 ± 0.8 to 2.76 ± 0.7 in follow up. A trend suggesting that patients with poor preoperative PFT has more ICU duration and worse outcome. In patients with mild acid-base disorders, extubation was possible within 24 hours. Out of 26 patients with ICU duration less than 2 days, 23 patients had "good" outcome, whereas ten out of 40 patients with ICU duration of more than or equal to 2 days had "bad" outcome (P = 0.00). Conclusion: Patients having moderate to severe primary or mixed acid-base disorder have a probability of re-intubation or delayed extubation. A strong correlation was seen with the novel grading system (grade >6 had worse outcome).

Comparison of Recovery Profiles of Patients Undergoing Endoscopic Lumbar Discectomy under Desflurane, Propofol, or Sevoflurane Anesthesia: A Randomized, Prospective, Clinical, Comparative Study.

Background Agents like propofol, sevoflurane, and desflurane having rapid revival of psychomotor and cognitive functions translating into reliable anesthetic recovery are chosen for day care procedures. This prospective randomized comparative study was undertaken to compare the psychomotor and cognitive functions of patients undergoing discectomy under different anesthetic strategies. Methods Seventy-five adult American Society of Anesthesiologists grade I and II patients being operated for endoscopic lumbar discectomy under different anesthetic regimens were enrolled and were subjected to Trieger Dot Test (TDT), Digit Symbol Substitution Test (DSST), and Mini-Mental State Examination (MMSE) preoperatively at specified intervals postoperatively. There emergence and early recovery times, complications, and satisfaction levels were also noted. Results No difference was found in the postoperative TDT and DSST and MMSE scores among the groups at all the time points (15 minutes, 3 minutes, 1 hour, 2 hours, 3 hours, and 4 hours). TDT and DSST demonstrated a tendency to return to baseline by 2nd and 3rd hour postoperatively. Emergence and early recovery times were earlier in the inhalation groups ( p 0.005 and 0.007, respectively). Time required to attain a Modified Aldrete Score of 9, complications, and observed side effects were similar among the groups. Conclusion Patients in the three groups had similar impairments in their psychomotor and cognitive functions which recovered at comparable time periods postoperatively. Emergence and early recovery were, however, faster in the desflurane group.

Nanoengineering InP Quantum Dot-Based Photoactive Biointerfaces for Optical Control of Neurons.

Light-activated biointerfaces provide a non-genetic route for effective control of neural activity. InP quantum dots (QDs) have a high potential for such biomedical applications due to their uniquely tunable electronic properties, photostability, toxic-heavy-metal-free content, heterostructuring, and solution-processing ability. However, the effect of QD nanostructure and biointerface architecture on the photoelectrical cellular interfacing remained unexplored. Here, we unravel the control of the photoelectrical response of InP QD-based biointerfaces via nanoengineering from QD to device-level. At QD level, thin ZnS shell growth (∼0.65 nm) enhances the current level of biointerfaces over an order of magnitude with respect to only InP core QDs. At device-level, band alignment engineering allows for the bidirectional photoelectrochemical current generation, which enables light-induced temporally precise and rapidly reversible action potential generation and hyperpolarization on primary hippocampal neurons. Our findings show that nanoengineering QD-based biointerfaces hold great promise for next-generation neurostimulation devices.

Bidirectional optical neuromodulation using capacitive charge-transfer.

Artificial control of neural activity allows for understanding complex neural networks and improving therapy of neurological disorders. Here, we demonstrate that utilization of photovoltaic biointerfaces combined with light waveform shaping can generate safe capacitive currents for bidirectional modulation of neurons. The differential photoresponse of the biointerface due to double layer capacitance facilitates the direction control of capacitive currents depending on the slope of light intensity. Moreover, the strength of capacitive currents is controlled by changing the rise and fall time slope of light intensity. This approach allows for high-level control of the hyperpolarization and depolarization of membrane potential at single-cell level. Our results pave the way toward advanced bioelectronic functionalities for wireless and safe control of neural activity.

Randomized Trial to Compare Plasma Glucose Trends in Patients Undergoing Surgery for Supratentorial Gliomas under Maintenance of Sevoflurane, Desflurane, and Propofol.

BACKGROUND: Anesthetic agents influence the glycemic response by affecting the neuroendocrine surgical response or directly modifying pancreatic insulin release. Due to chances of neuronal damage, intraoperative hyperglycemia and hypoglycemia both are detrimental for patients undergoing neurosurgeries. Inhalational (sevoflurane and desflurane) and intravenous (propofol) agents have been found to raise intraoperative glucose levels in nonneurological surgeries. AIM: We aimed to compare the intraoperative glucose levels in supratentorial glioma surgeries under the maintenance of three anesthetic agents such as sevoflurane, desflurane, and propofol. MATERIALS AND METHODS: This randomized trial was conducted with 90 nondiabetic adults with supratentorial glioma. Thirty patients were allocated randomly to the three groups receiving sevoflurane, desflurane, and propofol. Baseline and hourly plasma glucose levels were recorded. Postoperatively, the time required to achieve an Aldrete score of 9 and complications were assessed. RESULTS: Baseline plasma glucose levels were 111.23 ± 11.67, 109.47 ± 19.75, and 111.7 ± 13.88 mg/dL (P = 0.84) in sevoflurance, desflurane, and propofol group, respectively. All of them showed an elevation of plasma glucose in relation to the time of surgery with variable trends. In the 4th and 5th h, the elevations in the inhalational groups (sevoflurane and desflurane) were significantly higher than the propofol group (P = 0.003 and 0.002, respectively). The time for achieving Aldrete's score of 9 was higher in the propofol group (P < 0.0001). No differences were observed in the duration of hospital stay or complications. CONCLUSIONS: Maintenance of anesthesia in nondiabetic patients showed clinically modest rise of plasma glucose which is higher in patients under sevoflurane and desflurane than under propofol. However, the immediate recovery was faster with inhalational agents compared to propofol-based anesthesia.

Efficient photocapacitors via ternary hybrid photovoltaic optimization for photostimulation of neurons.

Optoelectronic photoelectrodes based on capacitive charge-transfer offer an attractive route to develop safe and effective neuromodulators. Here, we demonstrate efficient optoelectronic photoelectrodes that are based on the incorporation of quantum dots (QDs) into poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-Phenyl-C61-butyric acid methyl ester (PCBM) bulk heterojunction. We control the performance of the photoelectrode by the blend ratio, thickness, and nanomorphology of the ternary bulk heterojunction. The optimization led to a photocapacitor that has a photovoltage of 450 mV under a light intensity level of 20 mW.cm-2 and a responsivity of 99 mA/W corresponding to the most light-sensitive organic photoelectrode reported to date. The photocapacitor can facilitate action potential generation by hippocampal neurons via burst waveforms at an intensity level of 20 mW.cm-2. Therefore, the results point to an alternative direction in the engineering of safe and ultra-light-sensitive neural interfaces.

Organic Photovoltaic Pseudocapacitors for Neurostimulation.

Neural interfaces are the fundamental tools to understand the brain and cure many nervous-system diseases. For proper interfacing, seamless integration, efficient and safe digital-to-biological signal transduction, and long operational lifetime are required. Here, we devised a wireless optoelectronic pseudocapacitor converting the optical energy to safe capacitive currents by dissociating the photogenerated excitons in the photovoltaic unit and effectively routing the holes to the supercapacitor electrode and the pseudocapacitive electrode-electrolyte interfacial layer of PEDOT:PSS for reversible faradic reactions. The biointerface showed high peak capacitive currents of ∼3 mA·cm-2 with total charge injection of ∼1 µC·cm-2 at responsivity of 30 mA·W-1, generating high photovoltages over 400 mV for the main eye photoreception colors of blue, green, and red. Moreover, modification of PEDOT:PSS controls the charging/discharging phases leading to rapid capacitive photoresponse of 50 µs and effective membrane depolarization at the single-cell level. The neural interface has a device lifetime of over 1.5 years in the aqueous environment and showed stability without significant performance decrease after sterilization steps. Our results demonstrate that adopting the pseudocapacitance phenomenon on organic photovoltaics paves an ultraefficient, safe, and robust way toward communicating with biological systems.

Plasmon-Coupled Photocapacitor Neuromodulators.

Efficient transduction of optical energy to bioelectrical stimuli is an important goal for effective communication with biological systems. For that, plasmonics has a significant potential via boosting the light-matter interactions. However, plasmonics has been primarily used for heat-induced cell stimulation due to membrane capacitance change (i.e., optocapacitance). Instead, here, we demonstrate that plasmonic coupling to photocapacitor biointerfaces improves safe and efficacious neuromodulating displacement charges for an average of 185% in the entire visible spectrum while maintaining the faradic currents below 1%. Hot-electron injection dominantly leads the enhancement of displacement current in the blue spectral window, and the nanoantenna effect is mainly responsible for the improvement in the red spectral region. The plasmonic photocapacitor facilitates wireless modulation of single cells at three orders of magnitude below the maximum retinal intensity levels, corresponding to one of the most sensitive optoelectronic neural interfaces. This study introduces a new way of using plasmonics for safe and effective photostimulation of neurons and paves the way toward ultrasensitive plasmon-assisted neurostimulation devices.

High-Performance, Large-Area, and Ecofriendly Luminescent Solar Concentrators Using Copper-Doped InP Quantum Dots.

Colloidal quantum dots (QDs) are promising building blocks for luminescent solar concentrators (LSCs). For their widespread use, they need to simultaneously satisfy non-toxic material content, low reabsorption, high photoluminescence quantum yield, and large-scale production. Here, copper doping of zinc carboxylate-passivated InP core and nano-engineering of ZnSe shell facilitated high in-device quantum efficiency of QDs over 80%, having well-matched spectral emission profile with the photo-response of silicon solar cells. The optimized QD-LSCs showed an optical quantum efficiency of 37% and an internal concentration factor of 4.7 for a 10 × 10-cm2 device area under solar illumination, which is comparable with the state-of-the-art LSCs based on cadmium-containing QDs and lead-containing perovskites. Synthesis of the copper-doped InP/ZnSe QDs in gram-scale and large-area deposition (3,000 cm2) onto commercial window glasses via doctor-blade technique showed their scalability for mass production. These results position InP-based QDs as a promising alternative for efficient solar energy harvesting.

Entanglement production by interaction quenches of quantum chaotic subsystems.

The entanglement production in bipartite quantum systems is studied for initially unentangled product eigenstates of the subsystems, which are assumed to be quantum chaotic. Based on a perturbative computation of the Schmidt eigenvalues of the reduced density matrix, explicit expressions for the time-dependence of entanglement entropies, including the von Neumann entropy, are given. An appropriate rescaling of time and the entropies by their saturation values leads a universal curve, independent of the interaction. The extension to the nonperturbative regime is performed using a recursively embedded perturbation theory to produce the full transition and the saturation values. The analytical results are found to be in good agreement with numerical results for random matrix computations and a dynamical system given by a pair of coupled kicked rotors.

Proximal penholding method - A variant to enhance safety of ultrasoundguided central venous cannulation: A prospective pilot study.

Aims: A significant incidence of Posterior Vessel Wall Puncture (PVWP) was reported during ultrasound guidance (USG) for internal jugular vein (IJV) catheterization. We studied a new technique of USGIJV cannulation to minimize or avoid PVWP, thereby decreasing overall complication rate, irrespective of the operators' experience level. Materials and Methods: After ethical approval, a prospective study was conducted on adult patients of either gender between 18-65 years of age, belonging to the American Society of Anesthesiologists Physical Status I-III, undergoing general anesthesia and requiring USG-guided IJV cannulation. After induction of general anesthesia and intubation, USG-guided IJV cannulation was done using technique of "proximal pen-holding method" in patients placed in supine position with neck rotated in 15° rotation to the opposite side. The primary outcome was defined as success rate of USG-guided IJV cannulation and incidence of PVWP. The secondary outcome was the incidences of complications such as arterial puncture, adjacent tissue damage, and performer's ease of the procedure (0-10 scale; 0 denoting no ease and extreme difficulty and 10 denoting extreme ease and no difficulty). Results: In 135 patients, right IJV puncture, guidewire, and central line insertion were achieved in single attempt without any PVWP by nine operators which included two anesthesia consultants and seven senior registrars. No complications were reported and ease of procedure were rated as median (interquartile range) of 10 (10). Conclusions: The "proximal pen-holding method" for real-time USG-IJV cannulation helped in avoiding PVWP with lesser complication rate and greater performer's ease.

Patient Transportation Delays and Effects on Operation Theatres' Efficiency: A Study for Problem Analysis and Remedial Measures.

BACKGROUND AND AIMS: Delay in patients' transportation to the operating theater (OT) is a globally recognized phenomenon, leading to delay in the subsequent processes (anesthesia induction, surgery, and patient turnover). This observational study was conducted to evaluate the common reasons for delay in transporting patients to the neurosurgery OT complex and its consequent effects and how the elimination of these reasons by application of feasible measures can influence the after effects. SETTINGS AND DESIGN: This was an anesthesiologist-based audit of transportation process of patients to the OT complex of a tertiary care teaching hospital to identify the impediments and effects of delay, suggest and implement remedial measures, and assess the outcomes. MATERIALS AND METHODS: The movement process of successive 551 patients was studied. In the evaluation phase, common reasons for transportation delays were identified. The incidences of consequent effects such as second-case cancellations and overrunning of OTs beyond scheduled hours were noted. In the implementation phase, corrective measures were instituted and the incidences of delays and the consequent effects were again noted. STATISTICAL ANALYSIS: Statistical analysis was performed using SPSS 17.0. RESULTS: In the evaluation phase (303 patients), common reasons for delays included porter-associated delays (15), unavailable lifts (7), and pediatric patients (6). The incidences of case cancellation (20) and overrunning of OTs (9) were high. In the implementation phase, after remedial measures were enforced, the incidences of delays due to porter, lifts, and pediatric patients dropped to 1, 6, and 0, respectively. Simultaneously, a decrease in second-case cancellation (2) and overrunning of OTs (7) also reduced. As an additional finding, a significant reduction in OT turnover times was also observed (16.31 ± 9.29 min vs. 11.70 ± 5.78 min). CONCLUSIONS: Analysis of common reasons of patient transportation delays and removal of these impediments can markedly improve the efficiency in OT functioning.

Exact relaxation dynamics and quantum information scrambling in multiply quenched harmonic chains.

The quantum dynamics of isolated systems under quench condition exhibits a variety of interesting features depending on the integrable/chaotic nature of system. We study the exact dynamics of trivially integrable system of harmonic chains under a multiple quench protocol. Out of time ordered correlator of two Hermitian operators at large time displays scrambling in the thermodynamic limit. In this limit, the entanglement entropy and the central component of momentum distribution both saturate to a steady-state value. We also show that reduced density matrix assumes the diagonal form long after multiple quenches for large system size. These exact results involving infinite-dimensional Hilbert space are indicative of dynamical equilibration for a trivially integrable harmonic chain.

Ecofriendly and Efficient Luminescent Solar Concentrators Based on Fluorescent Proteins.

In recent years, luminescent solar concentrators (LSCs) have received renewed attention as a versatile platform for large-area, high-efficiency, and low-cost solar energy harvesting. So far, artificial or engineered optical materials, such as rare-earth ions, organic dyes, and colloidal quantum dots (QDs) have been incorporated into LSCs. Incorporation of nontoxic materials into efficient device architectures is critical for environmental sustainability and clean energy production. Here, we demonstrated LSCs based on fluorescent proteins, which are biologically produced, ecofriendly, and edible luminescent biomaterials along with exceptional optical properties. We synthesized mScarlet fluorescent proteins in Escherichia coli expression system, which is the brightest protein with a quantum yield of 61% in red spectral region that matches well with the spectral response of silicon solar cells. Moreover, we integrated fluorescent proteins in an aqueous medium into solar concentrators, which preserved their quantum efficiency in LSCs and separated luminescence and wave-guiding regions due to refractive index contrast for efficient energy harvesting. Solar concentrators based on mScarlet fluorescent proteins achieved an external LSC efficiency of 2.58%, and the integration at high concentrations increased their efficiency approaching to 5%, which may facilitate their use as "luminescent solar curtains" for in-house applications. The liquid-state integration of proteins paves a way toward efficient and "green" solar energy harvesting.