Large Time Window Research Articles

Dual-grating single-shot pump–probe technique

Abstract A simple and effective single-shot pump–probe technique is reported for studying ultrafast dynamic processes in various materials. Using only two commercial gratings, a large time window of ∼95.58 ps is spatially encoded in a single probe pulse, and single-shot time-resolved measurements are implemented. The time window in this single-shot pump–probe technique exceeds the maximum values in those reported works using the echelon or angle beam encoding strategy. The phase difference difficulty in the echelon encoding strategies is also overcome in our method, where a customized echelon is not necessary. The ultrafast dynamic processes of ZnSe and indolium squaraine (ISQ) at a wavelength of 650 nm were investigated using this technique for validation. The single-shot dynamics of ZnSe show an ultrafast two-photon absorption process followed by a weaker slow-recovery carrier absorption process. In the ISQ, a strong ground-state bleaching process is also observed. The transmittance of ISQ increases significantly after impulsive light excitation and maintains a slow increase until a time delay of ∼80 ps, which can be attributed to the transition from the Sn state to the S 1 state. In addition, a comparison with the previously reported single-shot pump–probe technique highlights the advantages of our technique.

A supersymmetric quantum perspective on the explicit large deviations for reversible Markov jump processes, with applications to pure and random spin chains

The large deviations at various levels that are explicit for Markov jump processes satisfying detailed balance are revisited in terms of the supersymmetric quantum Hamiltonian H that can be obtained from the Markov generator via a similarity transformation. We first focus on the large deviations at level 2 for the empirical density p^(C) of the configurations C seen during a trajectory over the large time window [0,T] , and rewrite the explicit Donsker–Varadhan rate function as the matrix element I[2][p^(.)]=⟨p^|H|p^⟩ involving the square-root ket |p^⟩ . (The analog formula is also discussed for reversible diffusion processes as a comparison.) We then consider the explicit rate functions at higher levels, in particular for the joint probability of the empirical density p^(C) and the empirical local activities a^(C,C′) characterizing the density of jumps between two configurations (C,C′) . Finally, the explicit rate function for the joint probability of the empirical density p^(C) and of the empirical total activity A^ that represents the total density of jumps of a long trajectory is written in terms of the two matrix elements ⟨p^|H|p^⟩ and ⟨p^|Hoff|p^⟩ , where Hoff represents the off-diagonal part of the supersymmetric Hamiltonian H. This general framework is then applied to pure or random spin chains with single-spin-flip or two-spin-flip transition rates, where the supersymmetric Hamiltonian H corresponds to quantum spin chains with local interactions involving Pauli matrices of two or three neighboring sites. It is then useful to introduce the quantum density matrix ρ^=|p^⟩⟨p^| associated with the empirical density p^(.) in order to rewrite the various rate functions in terms of reduced density matrices involving only two or three neighboring sites.

Prognostic Value of Pentraxin 3 and Procalcitonin in Late onset Neonatal Sepsis

Abstract Background Sepsis is a major cause of intensive care unit (ICU) admission. Procalcitonin (PCT) could be an important prognostic marker for sepsis. Pentraxin 3 (PTX3) and PCT are detectable in patients with sepsis within a large time window after the onset of sepsis. Objective To assess the prognostic value of the PTX3, PCT in neonatal sepsis in comparison with other sepsis screen. Patients and Methods A prospective study included 40 neonates with sepsis. The study had been conducted in the neonatal intensive care units of Ain Shams University, Children’s Hospital during the period from January 2020 to May 2022. All neonates had been subjected to clinical examination, anthropometric measurements and sepsis scoring by neonatal sequential organ failure assessment (nSOFA). Laboratory investigations were collected from all pediatrics including Complete blood count (CBC), quantitative C- reactive protein (CRP), blood culture, serum pentraxin 3 (PTX3) and serum procalcitonin (PCT). Sepsis markers had been obtained from neonates at the day of being with suspected sepsis before starting the antimicrobial therapy (Day 0). While blood samples for sepsis markers reobtained only from neonates with positive blood cultures on the 3rd (Day3), accordingly our patients divided into improved and deteriorated groups. Results There was a significant decrease in CRP level and increase in procalcitonin and pentraxin 3 levels in deteriorated group than improved group at baseline with p-value = 0.004, 0.016 and 0.019; respectively. Also, the study shows that there was a significant increase in CRP, procalcitonin and pentraxin 3 levels in deteriorated group than improved group after 3 days with p-value = 0.002, <0.001 and <0.001; respectively. Furthermore, in improved group, there was a significant decrease in the level of CRP, procalcitonin and pentraxin 3 after 3 days than at baseline with p-value = 0.001, <0.001 and 0.001; respectively. Also in deteriorated group, there was statistically significant increase in the CRP and pentraxin 3 levels after 3 days than at baseline in deteriorated group with p- value = 0.002 and 0.019; respectively while no change found in procalcitonin level. Conclusion Serum pentraxin 3 and procalcitonin levels seem to be promising prognostic markers in neonatal sepsis with higher sensitivity and specificity for procalcitonin than pentraxin at 3 days.

The Utility of High-Intensity, Intermittent Exercise Protocols to Induce Fatigue for Screening Purposes in Jump-Landing Sports.

Short-term fatigue protocols simulating sports participation are scarce and not well-documented in jump-landing sports. Therefore, this study investigated physiological and physical responses following high-intensity, intermittent exercise protocols (HIIPs) with a standardized level of subjective exhaustion (Borg ≥18/20) and a modified fixed version of five circuits (HIIP-5) for future inclusion in biomechanical screening protocols. Twenty male volleyball and basketball players participated in this study to complete the HIIP and the HIIP-5. Physiological and physical variables were assessed before and up to 30 min after cessation of both protocols. Regarding physiological variables, heart rate values increased (+104 bpm, p < 0.001) and remained elevated up to 30 min (+34 bpm, p < 0.001), and blood lactate levels increased (+17 mmol/l, p < 0.001) compared to baseline. Regarding physical variables, decreased jump height (-4 cm, p = 0.001-0.009) and quadriceps muscle strength (p = 0.001-0.050) were observed up to 30 min compared to baseline. The type of the fatigue protocol did not have an effect on the investigated variables (p > 0.05). To conclude, both the HIIP and the HIIP-5 seem valuable tools to induce acute and long-lasting responses, providing a sufficiently large time window of 30 min within which biomechanical markers of injury can be assessed under fatigued conditions in future risk factor screenings. In practice, the fatigue protocol can be terminated after only five circuits if athletes had not yet been stopped at that point due to exhaustion (Borg ≥18/20).

Single-shot pump-probe technique by the combination of an echelon and a grating with a time window of 109 ps

In this study, using only a single pulse, pump-probe measurement with a large time window of more than 100 ps is implemented. A commercial grating is used to encode a time window of ∼56 ps in a single pulse; therefore, there is no need for machining customization. In addition, in this technique, the grating surface is accurately imaged, eliminating the image blur problem caused by phase differences in previous echelon-based techniques. Moreover, to make full use of the grating surface and obtain a larger time window, a simple reflection echelon is combined that matches the grating in the time window. This combination encoding strategy results in a total time window of ∼109 ps and maintains accurate imaging of the grating surface. This time window is an order of magnitude greater than the maximum reported values of the echelon encoding strategy and the angle beam encoding strategy. To demonstrate this single-shot pump-probe technique, the two-photon absorption process of ZnSe and the excited-state absorption process of a symmetrical phenoxazinium bromine salt were studied. The possibility of further improving the experimental setup is also discussed.

Long-duration environmental biosensing by recording analyte detection in DNA using recombinase memory.

Microbial biosensors that convert environmental information into real-time visual outputs are limited in their sensing abilities in complex environments, such as soil and wastewater, due to optical inaccessibility. Biosensors that could record transient exposure to analytes within a large time window for later retrieval represent a promising approach to solve the accessibility problem. Here, we test the performance of recombinase-memory biosensors that sense a sugar (arabinose) and a microbial communication molecule (3-oxo-C12-L-homoserine lactone) over 8 days (~70 generations) following analyte exposure. These biosensors sense the analyte and trigger the expression of a recombinase enzyme which flips a segment of DNA, creating a genetic memory, and initiates fluorescent protein expression. The initial designs failed over time due to unintended DNA flipping in the absence of the analyte and loss of the flipped state after exposure to the analyte. Biosensor performance was improved by decreasing recombinase expression, removing the fluorescent protein output, and using quantitative PCR to read out stored information. Application of memory biosensors in wastewater isolates achieved memory of analyte exposure in an uncharacterized Pseudomonas isolate. By returning these engineered isolates to their native environments, recombinase-memory systems are expected to enable longer duration and in situ investigation of microbial signaling, cross-feeding, community shifts, and gene transfer beyond the reach of traditional environmental biosensors.IMPORTANCEMicrobes mediate ecological processes over timescales that can far exceed the half-lives of transient metabolites and signals that drive their collective behaviors. We investigated strategies for engineering microbes to stably record their transient exposure to a chemical over many generations through DNA rearrangements. We identify genetic architectures that improve memory biosensor performance and characterize these in wastewater isolates. Memory biosensors are expected to be useful for monitoring cell-cell signals in biofilms, detecting transient exposure to chemical pollutants, and observing microbial cross-feeding through short-lived metabolites within cryptic methane, nitrogen, and sulfur cycling processes. They will also enable in situ studies of microbial responses to ephemeral environmental changes, or other ecological processes that are currently challenging to monitor non-destructively using real-time biosensors and analytical instruments.

Inverse problem in the conditioning of Markov processes on trajectory observables: what canonical conditionings can connect two given Markov generators?

In the field of large deviations for stochastic dynamics, the canonical conditioning of a given Markov process with respect to a given time-local trajectory observable over a large time-window has attracted a lot of interest recently. In the present paper, we analyze the following inverse problem: when two Markov generators are given, is it possible to connect them via some canonical conditioning and to construct the corresponding time-local trajectory observable? We focus on continuous-time Markov processes and obtain the following necessary and sufficient conditions: (i) for continuous-time Markov jump processes, the two generators should involve the same possible elementary jumps in configuration space, i.e. only the values of the corresponding rates can differ; (ii) for diffusion processes, the two Fokker–Planck generators should involve the same diffusion coefficients, i.e. only the two forces can differ. In both settings, we then construct explicitly the various time-local trajectory observables that can be used to connect the two given generators via canonical conditioning. This general framework is illustrated with various applications involving a single particle or many-body spin models. In particular, we describe several examples to show how non-equilibrium Markov processes with non-vanishing steady currents can be interpreted as the canonical conditionings of detailed-balance processes with respect to explicit time-local trajectory observables.

“Mother's milk”: Is there a social reversal in breastfeeding practices along with economic development?

Previous studies suggest that macro- and micro-level factors jointly influence breastfeeding (BF) practices, but empirical evidence on the dynamics of such interactions along with the process of a country's economic development remains limited. Based on 42 Demographic Health Surveys (DHS) conducted in 15 Asian countries with a large time window (1990–2017), we thus test the existence of a reversal in the association between household wealth and BF practices throughout the development process. Four BF indicators (early initiation of BF, exclusive BF, continued BF at one year and two years) are examined, along with a standardized asset-based household wealth index allowing for cross-wave and cross-country comparisons. To highlight the dynamics of the wealth-BF association, we carry out econometric estimations, including interaction terms between household wealth and the country's level of economic development (low, medium, and high) or time. Instrumental variable estimations are also performed to limit suspected endogeneity issues. Our results confirm a transition in the wealth gradient of exclusive BF and continued BF in Asian countries. More precisely, while these practices are pro-poor in the poorest countries of the sample, they progressively spread to wealthier households along with the level of economic development. For exclusive BF, this transition has resulted in a reversal of the wealth gradient at the end of the period (i.e., exclusive BF prevalence among the rich overpassing that of the poor). We fail, however, to observe this kind of transition for early initiation of BF, this practice remaining pro-poor, whatever the level of economic development. To sum up, our results provide robust evidence of a transition in the wealth gradient of some BF practices along with economic development and time, and thus largely echo the literature exploring the social reversal hypothesis in the case of non-communicable diseases.

Large deviations for the Pearson family of ergodic diffusion processes involving a quadratic diffusion coefficient and a linear force

The Pearson family of ergodic diffusions with a quadratic diffusion coefficient and a linear force is characterized by explicit dynamics of their integer moments and by explicit relaxation of spectral properties towards their steady state. Besides the Ornstein–Uhlenbeck process with a Gaussian steady state, other representative examples of the Pearson family are the square root or the Cox–Ingersoll–Ross process converging towards the gamma distribution, the Jacobi process converging towards the beta distribution, the reciprocal gamma process (corresponding to an exponential functional of the Brownian motion) that converges towards the inverse-gamma distribution, the Fisher–Snedecor process and the Student process. The last three steady states display heavy tails. The goal of the present paper is to analyze the large deviation properties of these various diffusion processes in a unified framework. We first consider level 1 concerning time-averaged observables over a large time window T. We write the first rescaled cumulants for generic observables and identify specific observables whose large deviations can be explicitly computed from the dominant eigenvalue of the appropriate deformed generator. The explicit large deviations at level 2 concerning the time-averaged density are then used to analyze the statistical inference of model parameters from data on a very long stochastic trajectory in order to obtain the explicit rate function for the two inferred parameters of the Pearson linear force.

Spatial and temporal averaging in the homogenisation of the elastodynamic response of periodic laminates

This paper suggests a methodology to obtain homogenised material properties from a transient dynamic numerical model. The standard Hill–Mandel Principle, based on spatial averages, is extended with time averaging. Thus, in addition to a sufficiently large Representative Volume Element (RVE) to carry out the averaging in space, a sufficiently large time window is required to carry out the time averaging. The space–time averaging procedure is validated for a periodic laminate bar subjected to a variety of boundary conditions, impedance contrasts and loading conditions. The homogenised results converge to the analytical solutions and confirm that having a higher impedance contrast between laminate components requires not only larger RVE sizes but also longer time averaging windows. The most efficient macroscopic approximation is obtained by a balanced increase in RVE size and time averaging window.

Abstract P6-01-38: Predictive efficacy biomarker for chemotherapy agents against triple-negative breast cancer bioprinted organoid tumors (BOTs) using solid tumor biopsy-on-a-chip

Abstract Background: Despite $90 billion in preclinical research and clinical trials every year, 90% of cancer clinical trials are unsuccessful. Thus, there is considerable interest in predicting clinical efficacy of preclinical formulations early in discovery using patient derived ex vivo platforms. However, extracting adequate tissue for such models can be difficult depending on tumor type and site. Dominant mechanisms for expanding patient tissue include xenografts and organoids. However, the former imposes a large time window to establish while the latter is constrained in space by sizescales. Here, we present a novel approach for expanding TNBC tissue, specifically for use in ex vivo models, that addresses these constrains with 3D bioprinted organoid tumors (BOTs). Objective: The aim of this study is to generate TNBC BOTs that mimic core biopsy tissue for use in ex vivo precision and personalized predictive biomarkers for chemotherapies. Methods: BOTs were generated using alginate-based bioink prepared with MDA-MB-231 TNBC cells. Briefly, specially prepared fresh TNBC bioink was deposited layer-by-layer using a Cellink BIO X6 bioprinter in geometrical configurations to mimic 14- to 18- gauge tumor biopsies. These were chemically cross-linked and cured in stages to allow cells and matrix to self-assemble with limited degrees of freedom. Fully cured BOTs were loaded in our ex vivo solid tumor biopsy-on-a-chip and treated with chemotherapy agents to evaluate sensitivity and resistance, with outcomes determined using immunofluorescent live and dead cell staining methods. Results: A 3-minute crosslinking time with calcium chloride provided a stable and functional sodium alginate medium for treating cellular BOTs. Two layers of TNBC bioink was determined to be the optimal size and shape for compatibility with our ex vivo biopsy-on-a-chip predictive efficacy biomarker platform. TNBC cells were verified to be evenly distributed within the cured sodium alginate matrix using live cell nuclear stains. Successful diffusion of multiple agents to spatially distinct regions of the bioprinted tissue was verified with fluorescently labeled small molecules and nucleic acid stains up to 200 µM deep. Impact: Patient derived BOT core mimics and other configurations could be used in ex vivo breast cancer chemotherapy screening models to obtain sensitivity and resistance profiles as predictive functional biomarkers both on the bedside for personalized treatment strategy development and on the bench to uncover new therapeutic targets. Due to their potential to replicate biophysical and biochemical characteristics of a tumor and its microenvironment, BOT based precision and personalized medicine platforms can provide more accurate drug efficacy readout compared to in vitro cancer models. Citation Format: Seth Bollenbecker, Zeelu Patel, Zeenia Punjani, Areesha Charania, Heli Patel, Alyssa Abbott, Kaitlyn Kunkle, Mary Kathryn Sewell-Loftin, Gregory Grossman, Karim Budhwani. Predictive efficacy biomarker for chemotherapy agents against triple-negative breast cancer bioprinted organoid tumors (BOTs) using solid tumor biopsy-on-a-chip [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-01-38.

In-silico evaluation of adenoviral COVID-19 vaccination protocols: Assessment of immunological memory up to 6 months after the third dose.

The immune response to adenoviral COVID-19 vaccines is affected by the interval between doses. The optimal interval is unknown. We aim to explore in-silico the effect of the interval between vaccine administrations on immunogenicity and to analyze the contribution of pre-existing levels of antibodies, plasma cells, and memory B and T lymphocytes. We used a stochastic agent-based immune simulation platform to simulate two-dose and three-dose vaccination protocols with an adenoviral vaccine. We identified the model's parameters fitting anti-Spike antibody levels from individuals immunized with the COVID-19 vaccine AstraZeneca (ChAdOx1-S, Vaxzevria). We used several statistical methods, such as principal component analysis and binary classification, to analyze the correlation between pre-existing levels of antibodies, plasma cells, and memory B and T cells to the magnitude of the antibody response following a booster dose. We find that the magnitude of the antibody response to a booster depends on the number of pre-existing memory B cells, which, in turn, is highly correlated to the number of T helper cells and plasma cells, and the antibody titers. Pre-existing memory T cytotoxic cells and antibodies directly influence antigen availability hence limiting the magnitude of the immune response. The optimal immunogenicity of the third dose is achieved over a large time window, spanning from 6 to 16 months after the second dose. Interestingly, after any vaccine dose, individuals can be classified into two groups, sustainers and decayers, that differ in the kinetics of decline of their antibody titers due to differences in long-lived plasma cells. This suggests that the decayers may benefit from a tailored boosting schedule with a shorter interval to avoid the temporary loss of serological immunity.

64Cu-DOTHA2-PSMA, a Novel PSMA PET Radiotracer for Prostate Cancer with a Long Imaging Time Window.

Prostate cancer imaging and late-stage management can be improved with prostate-specific membrane antigen (PSMA)-targeting radiotracers. We developed a PSMA positron emission tomography (PET) radiotracer, DOTHA2-PSMA radiolabeled with 64Cu (T1/2: 12.7 h), to leverage its large imaging time window. This preclinical study aimed to evaluate the biological and imaging properties of 64Cu-DOTHA2-PSMA. Its stability was assessed in plasma ex vivo and in mice. Cellular behavior was studied for up to 48 h in LNCaP cells. Biodistribution studies were performed in balb/c mice for up to 48 h. Dynamic (1 h) and static (4 h and 24 h) PET imaging was completed in LNCaP tumor-bearing mice. 64Cu-DOTHA2-PSMA was stable ex vivo in plasma and reached cellular internalization up to 34.1 ± 4.9% injected activity (IA)/106 cells at 48 h post-injection (p.i.). Biodistribution results showed significantly lower uptake in kidneys than 68Ga-PSMA-617, our reference PET tracer (p < 0.001), but higher liver uptake at 2 h p.i. (p < 0.001). PET images showed 64Cu-DOTHA2-PSMA’s highest tumoral uptake at 4 h p.i., with a significant difference between blocked and non-blocked groups from the time of injection to 24 h p.i. The high stability and tumor uptake with a long tumor imaging time window of 64Cu-DOTHA2-PSMA potentially contribute to the prostate cancer theranostic approach and its local recurrence detection.

Vaccination and variants: Retrospective model for the evolution of Covid-19 in Italy

The last year of Covid-19 pandemic has been characterized by the continuous chase between the vaccination campaign and the appearance of new variants that puts further obstacles to the possibility of eradicating the virus and returning to normality in a short period. In the present paper we develop a deterministic compartmental model to describe the evolution of the Covid-19 in Italy as a combined effect of vaccination campaign, new variant spreading and mobility restrictions. Particular attention is given to the mechanism of waning immunity, appropriately timed with respect to the effective progress of the vaccination campaign in Italy. We perform a retrospective analysis in order to explore the role that different mechanisms, such as behavioral changes, variation of the population mobility, seasonal variability of the virus infectivity, and spreading of new variants have had in shaping the epidemiological curve. We find that, in the large time window considered, the most relevant mechanism is the seasonal variation in the stability of the virus, followed by the awareness mechanism, that induces individuals to increase/relax self-protective measures when the number of active cases increases/decreases. The appearance of the Delta variant and the mobility variations have had instead only marginal effects. In absence of vaccines the emerging scenario would have been dramatic with a percentage difference in the number of total infections and total deaths, in both cases, larger than fifty per cent. The model also predicts the appearance of a more contagious variant (the Omicron variant) and its becoming dominant in January 2022.

Application of Fiedler Value for Mitigation of Loss of Connectivity in Wireless Mesh Networks

This paper proposes a new scheme for very fast detection of a sensor going offline or loss of connectivity of sensor in Wireless Mesh Networks (WMN) in order to avoid any packet loss. A sensor is declared offline by a gateway if it does not receive any packet from the sensor for a specific time interval termed as keep-alive time. In mesh networks, this keep-alive window is kept for a very long duration; sometimes it is as high as 2.5 to 3 hours. The time duration is kept high so that gateway does not declare a sensor that is in deep sleep to conserve battery, as offline. However, keeping a large keep-alive time window leads to the very likely possibility of missing the timely detection of a critical event like a smoke sensor or gas leak sensor going offline. In the proposed method, the gateway maintains its table of neighbourhood matrix in order to facilitate fast and efficient tracking as well as tracing of the nodes for the detection of the loss of connectivity of a sensor. A Laplacian matrix formulation proposed by Fiedler is invoked for tracking and tracing lost nodes of WMN. Through the Fiedler value, this paper substantiates the efficacy of monitoring a large WMN not only for its algebraic connectivity but also to compute the number of disconnected partitions in it. This is achieved through the number of null values of eigenvalues of the Laplacian matrix of the graph of WMN. Through simulation studies, this paper demonstrates achieving an 88 % success rate in the detection of disconnection with an average latency of 39.806 ms. On the contrary, a conventional process for the time duration after which a sensor can be declared offline might be an hour or even more depending upon the pre-set duration of the keep-alive time window.

Evaluating anticancer agents on 3D bioprinted organoid tumors (BOT) to reduce cost and accelerate therapeutic discovery.

e13500 Background: Despite recent advances in therapeutics, cancer remains the second leading cause of death worldwide. Next generation cancer models hold the promise of breaking this stranglehold. However, extracting adequate tissue for precision and personalized medicine ex vivo models can be difficult depending on tumor type and tissue site. Mechanisms to expand tissue include patient derived xenografts and patient derived organoids. The former imposes a large time window to establish while the latter is constrained in space by sizescales. Advances in 3D bioprinting have improved the ability to reproduce the three-dimensionality and heterogeneity of the tumor microenvironment. Here we present a novel mechanism to address space and time constrains with 3D bioprinted organoid tumors (BOT) that mimic core needle biopsy tissue to reduce both cost and time to market for novel therapeutics making effective cancer therapy more accessible and equitable. The aim of this study is to produce and use BOT core biopsy tissue in ex vivo precision and personalized medicine applications. Methods: Bioinks prepared with MDA-MB-231 cells, fibrinogen, and thrombin will be deposited layer-by-layer on microporous substrate, in various geometrical configurations, and cured in stages to allow cells and matrix to self-assemble with limited degrees of freedom. Bioprinted organoid tissue will be fully cured to mimic patient biopsy cores, which will then be loaded in ex vivo bioreactors to evaluate sensitivity and resistance of small molecule and biologics. Results: Tissue 3D microarchitecture was validated using high-content fluorescence imaging and custom image processing applications. Diffusion of mock agents, small molecule, and nucleic acid stains was measured 200 mm deep in tissue. Differential activity in spatially distinct regions of intact BOT cores was quantified using advanced image processing modules. Conclusions: Patient derived BOT cores could be used both as a predictive model to screen drugs on an individualized basis and to uncover new therapeutic targets to improve efficacy and reduce toxicity. Due to their ability to replicate the physical and biochemical characteristics of a tumor and its microenvironment, BOT based precision and personalized medicine models can provide more accurate data on drug efficacy and toxicology when compared to in vitro cancer models.

Ultra-permeable high-selective SAPO-34 membranes for efficient CO2 capture

Ultra-permeable SAPO-34 membranes with membrane thickness of 0.8–1.2 μm were reproducibly fabricated using diluted mother liquids with H2O/Al2O3 ratios of 300 and 450. The orientation and thickness of the membranes were greatly affected by mother liquid dilution. Thickness-even SAPO-34 membranes were reproducibly prepared in a large synthesis time window, indicating that membrane synthesis had good robustness and it is suitable to the scale-up fabrication. The membranes prepared at H2O/Al2O3 ratio of 450 displayed ultrahigh CO2 permeances of (1.0–1.3) × 10−5 mol (m2 s Pa)−1 (∼30000–37000 GPU) and CO2/CH4 selectivities of (56–126) at 298 K and 0.2 MPa pressure drop. The typical membrane also displayed CO2 permeance of 7.6 × 10−6 mol (m2 s Pa)−1 (∼23000 GPU) and CO2/N2 selectivity of 35 for an equimolar CO2/N2 mixture. The separation performance of these thin SAPO-34 membranes was far beyond that of most reported membranes. Such CO2 permeances of the membranes are 200–350 times higher than that of commercial polyimide membranes. The membranes shows great potentials for CO2 capture from natural and flue gases.

Low resolution fourier synthesis modelling for underwater acoustic channel impulse response

Fourier synthesis is the most widely used method for underwater acoustic broadband modeling. Traditionally, high frequency resolution and large time window length are needed to generate broadband time series to avoid aliasing in time domain. An optimized Fourier synthesis method is presented in this paper to accelerate the impulse response function modelling. The method consists of two steps, the phase-frequency response reconstruction and the impulse response function time window determination. The impulse response function of a range-dependent ocean channel is modeled using the proposed method with different frequency resolutions and compared with the interpolation method and traditional Fourier synthesis method. Modeling results show that the proposed method requires only a tenth of the frequency resolution of the traditional Fourier synthesis method and the correlation coefficients of modelling output time series are preserved above 95%. The proposed method also exhibits better phase response reconstruction performances than the interpolation method when the frequency resolution equals to 1 Hz.

On the Electron Temperature in the Topside Ionosphere as Seen by Swarm Satellites, Incoherent Scatter Radars, and the International Reference Ionosphere Model

The global statistical median behavior of the electron temperature (Te) in the topside ionosphere was investigated through in-situ data collected by Langmuir Probes on-board the European Space Agency Swarm satellites constellation from the beginning of 2014 to the end of 2020. This is the first time that such an analysis, based on such a large time window, has been carried out globally, encompassing more than half a solar cycle, from the activity peak of 2014 to the minimum of 2020. The results show that Swarm data can help in understanding the main features of Te in the topside ionosphere in a way never achieved before. Te data measured by Swarm satellites were also compared to data modeled by the empirical climatological International Reference Ionosphere (IRI) model and data measured by Jicamarca (12.0°S, 76.8°W), Arecibo (18.2°N, 66.4°W), and Millstone Hill (42.6°N, 71.5°W) Incoherent Scatter Radars (ISRs). Moreover, the correction of Swarm Te data recently proposed by Lomidze was applied and evaluated. These analyses were performed for two main reasons: (1) to understand how the IRI model deviates from the measurements; and (2) to test the reliability of the Swarm dataset as a new possible dataset to be included in the underlying empirical dataset layer of the IRI model. The results show that the application of the Lomidze correction improved the agreement with ISR data above all at mid latitudes and during daytime, and it was effective in reducing the mismatch between Swarm and IRI Te values. This suggests that future developments of the IRI Te model should include the Swarm dataset with the Lomidze correction. However, the existence of a quasi-linear relation between measured and modeled Te values was well verified only below about 2200 K, while for higher values it was completely lost. This is an important result that IRI Te model developers should properly consider when using the Swarm dataset.

On the inverse quenching technique applied to gelatin solutions

Gelatin gels are known to be nonequilibrium systems, because of the continuous growth and rearrangements of physical junctions, even in the solidlike state. Establishing a relationship between the relative degree of cross-linking and macroscopic elasticity would be crucial in understanding, modeling, and predicting the transformation processes of gelatin solutions. Performing rheological experiments on a distinct gel structure, with a definite number of cross-links, is, however, a challenging task. In isothermal conditions, indeed, the density of physical cross-links changes indefinitely, and network evolution cannot be arrested. Inspired by the inverse quenching technique applied in the past to semicrystalline polymers, we here apply an unusual thermal history to an aqueous solution of gelatin in the semiconcentrated regime (6.67%w pig-skin gelatin), in order to freeze the system in a metastable condition for a time sufficiently long to perform a rheological characterization. The solution, initially kept in the sol state at 60°C, is rapidly cooled below gelation temperature, and isothermal gelation is started at 10°C. After soaking at this low temperature for a given time, the sample is rapidly heated (inverse quenching) up to a value in the range 24–29 °C, where kinetics is monitored. If the waiting time at low temperature and the inverse quenching temperature are suitably chosen, sample elasticity will remain stationary for a relatively large time window, and rheological experiments can then be reliably performed.