Ventilation strategies to reduce airborne transmission of viruses in classrooms: A systematic review of scientific literature.

The recent pandemic due to SARS-CoV-2 has brought to light the need for strategies to mitigate contagion between human beings. Apart from hygiene measures and social distancing, air ventilation highly prevents airborne transmission within enclosed spaces. Among others, educational environments become critical in strategic planning to control the spread of pathogens and viruses amongst the population, mainly in cold conditions. In the event of a virus outbreak - such as COVID or influenza - many school classrooms still lack the means to guarantee secure and healthy environments. The present review examines school contexts that implement air ventilation strategies to reduce the risk of contagion between students. The analysed articles present past experiences that use either natural or mechanical systems assessed through mathematical models, numerical models, or full-scale experiments. For naturally ventilated classrooms, the studies highlight the importance of the architectural design of educational spaces and propose strategies for aeration control such as CO2-based control and risk-infection control. When it comes to implementing mechanical ventilation in classrooms, different systems with different airflow patterns are assessed based on their ability to remove airborne pathogens considering parameters like the age of air and the generation of airflow streamlines. Moreover, studies report that programmed mechanical ventilation systems can reduce risk-infection during pandemic events. In addition to providing a systematic picture of scientific studies in the field, the findings of this review can be a valuable reference for school administrators and policymakers to implement the best strategies in their classroom settings towards reducing infection risks.

Internal Delensing of Cosmic Microwave Background Polarization B-Modes with the POLARBEAR Experiment.

Using only cosmic microwave background polarization data from the polarbear experiment, we measure B-mode polarization delensing on subdegree scales at more than 5σ significance. We achieve a 14% B-mode power variance reduction, the highest to date for internal delensing, and improve this result to 22% by applying for the first time an iterative maximum a posteriori delensing method. Our analysis demonstrates the capability of internal delensing as a means of improving constraints on inflationary models, paving the way for the optimal analysis of next-generation primordial B-mode experiments.

A physico-chemical study on amphiphilic cyclodextrin/liposomes nanoassemblies with drug carrier potential.

In this paper, two medusa-like ACyDs, modified at the primary rim bearing four (ACyD4) and eight carbons (ACyD8) acyl chain length, and one bouquet-like CyD, modified at primary side with thiohexyl and at secondary one with oligoethylene moiety (SC6OH), were investigated for their ability to assemble in nanostructures or to form hybrid dipalmitoylphosphatidylcholine (DPPC)/ACyDs systems. The lipophilicity of these molecules and the different preparation methods used in this study (thin layer evaporation and nanoprecipitation method) significantly affect the aggregation behaviour in aqueous medium. Except for the shortest medusa-like ACyD4, the other ACyDs formed stable nanoaggregates for at least 45 days. The effect of ACyDs on the thermotropic behaviour of DPPC liposomes was also studied by differential scanning calorimetry analysis, thus elucidating their interaction with liposomes to afford hybrid liposome/ACyDs systems. The medusa-like ACyD4 cannot be used to realize nanosystems because it quickly aggregates or it induces a complete destabilization of the liposomes. At the highest concentration investigated (0.01 molar fraction), both ACyD8 and SC6OH interacted with DPPC liposomes, forming ACyD/DPPC or SC6OH/DPPC hybrid vesicular carriers.

Revisiting the role of sucrose in PLGA-PEG nanocarrier for potential intranasal delivery.

The efficient design of nanocarriers is a major challenge and must be correlated with the route of administration. Intranasal route is studied for local, systemic or cerebral treatments. In order to develop nanocarriers with suitable properties for intranasal delivery, to achieve brain and to market the product, it is extremely important the simplification of the formulation in terms of raw materials. Surfactants and cryoprotectants are often added to improve structuration and/or storage of polymeric nanoparticles. PLGA-PEG nanocarriers were prepared by nanoprecipitation method evaluating the critical role of sucrose as surfactant-like and cryoprotectant, with the aim to obtain a simpler formulation compared to those proposed in other papers. Photon correlation spectroscopy and Turbiscan analysis show that sucrose is a useful excipient during the preparation process and it effectively cryoprotects nanoparticles. Among the investigated nanocarriers with different degree of PEG, PEGylated PLGA (5%) confers weak interaction between nanoparticles and mucin as demonstrated by thermal analysis and mucin particle method. Furthermore, in vitro biological studies on HT29, as epithelium cell line, does not show cytotoxicity effect for this nanocarrier at all texted concentrations. The selected nanosystem was also studied to load docetaxel, as model drug, and characterized by a technological point of view.

Measles outbreak from February to August 2017 in Messina, Italy.

INTRODUCTION: Measles continues to be a major public health issue worldwide, with high morbidity and mortality rates. The disease remains endemic in 14 European countries, including Italy where, from 2013 to 2016, over 5,000 cases have been reported. In 2017, many Italian regions, including Sicily, have reported many cases of measles. In this study, we described the latest measles outbreak in the city of Messina, from 1st February to 31st August 2017. METHODS: We considered all reported measles cases that came to the "Public Health, Epidemiology and Preventive Medicine" Operative Unit of the Messina Provincial Health Agency Prevention Department, which receives all reported cases of measles in the Messina province. RESULTS: From 1st February to 31st August 2017, a total of 59 measles cases were reported, of which 44 were confirmed, nine were classified as possible, four were probable and two cases were discarded. Of the 57 possible, probable and confirmed cases, 31 (54%) were males and 26 (46%) were females. Moreover, 54 (95%) had not been previously vaccinated while the remaining cases had documented evidence of one (two cases) or two doses (one case). Genotype B3 was identified in 39/44 cases (88,6%) by the regional reference laboratory in Palermo. CONCLUSIONS: Despite the development of an effective vaccination, unfortunately measles continues to threaten the lives of millions of children worldwide each year. The suboptimal immunization level in Italy has led to an increase in the transmission of measles with detrimental effects on both public health and ongoing measles elimination efforts.

Catastrophic Thinning of Dielectric Elastomers.

We provide an energetic insight into the catastrophic nature of thinning instability in soft electroactive elastomers. This phenomenon is a major obstacle to the development of giant actuators, yet it is neither completely understood nor modeled accurately. In excellent agreement with experiments, we give a simple formula to predict the critical voltages for instability patterns; we model their shape and show that reversible (elastic) equilibrium is impossible beyond their onset. Our derivation is fully analytical, does not require finite element simulations, and can be extended to include prestretch and various material models.

Paritaprevir/ritonavir/ombitasvir+dasabuvir plus ribavirin therapy and inhibition of the anticoagulant effect of warfarin: a case report.

WHAT IS KNOWN AND OBJECTIVE: Paritaprevir/ritonavir/ombitasvir+dasabuvir (PrOD) is a direct-acting antiviral (DAA) approved for the treatment of chronic hepatitis C virus. We report on a probable interaction between PrOD with ribavirin and warfarin. CASE DESCRIPTION: Two weeks after the start of PrOD with ribavirin, the patient's international normalized ratio (INR) became subtherapeutic. Eleven weeks into therapy and following a 125% total increase in the weekly warfarin dose, therapeutic INR was achieved. Thirteen days after DAA therapy was completed and discontinued, the patient's INR became critically supratherapeutic. WHAT IS NEW AND CONCLUSION: Patients on PrOD plus ribavirin with warfarin should have INR followed closely upon initiation and discontinuation of therapy due to a probable drug interaction.

Innovative oral spray-dried Idebenone systems to improve patient compliance.

Idebenone is a high permeable drug with very slight water solubility that affects the dissolution rate in the biological fluids, causing an irregular and limited in vivo absorption after oral administration. Moreover, it is marketed in Europe as tablets equivalent to 150 mg, with the consequent administration of multiple dose of solid unit to obtain the correct dose, a deterrent for the patients' compliance. According to these considerations, our goal was to develop spray-dried microparticles using a soluble ß-cyclodextrin (CD) polymer and an enhancer of dissolution rate, such as carboxymethyl cellulose, to obtain a formulation easily dosable and soluble in water. The complex in solution was evaluated by phase solubility studies and the Idebenone/CD molar ratio selected was 1:1. According to Higuchi and Connors, adding carboxymethyl cellulose, a Bs-type profile was obtained. This result was due to the presence of carboxymethyl cellulose that competes with the CD in forming Idebenone microsystems, reducing of 10-fold the formulation bulk. UV-Vis absorption, (1)H nuclear magnetic resonance and circular dichroism showed the formation of the CD/Idebenone inclusion complex confirmed also by differential scanning calorimetry, Fourier transform infrared spectroscopy and fluorescence microscope (FM). The water solubility data and the in vitro dissolution tests performed in simulated gastric fluid, showed an increase of the drug water interaction due to the presence of the CD and carboxymethyl cellulose, both able to improve drug wettability, water solubility and dissolution rate. This approach seems to be suitable to produce microsystems which are able to enhance the in vivo absorption of Idebenone after oral administration and to increase the patient compliance.

Evaluation of sunscreen safety by in vitro skin permeation studies: effects of vehicle composition.

For sunscreens to be safe and effective, the lowest possible UV-filter percutaneous absorption should be achieved. In this paper, we evaluated in vitro release and permeation through human skin of two UV-filters, octyl methoxycinnammate (OMC) and butyl methoxydibenzoyl methane (BMBM) from six commercial O/W emulsions and we estimated their margin of safety (MoS). OMC and BMBM in vitro release and skin permeation were investigated in Franz-type diffusion cells and permeation data were used to calculate MoS. OMC in vitro skin permeation depended on both its concentration and vehicle composition while BMBM skin permeation depended on its release from the vehicle. MoS values were well beyond the lowest limit accepted for safe products. Although sunscreen skin permeation may depend on many factors, the commercial products investigated are safe under normal "in use" conditions.

Air change rates and infection risk in school environments: Monitoring naturally ventilated classrooms in a northern Italian urban context.

The importance of building ventilation in avoiding long-distance airborne transmission has been highlighted with the advent of the COVID-19 pandemics. Among others, school environments, in particular classrooms, present criticalities in the implementation of ventilation strategies and their impact on indoor air quality and risk of contagion. In this work, three naturally ventilated school buildings located in northern Italy have undergone monitoring at the end of the heating season. Environmental parameters, such as CO2 concentration and indoor/outdoor air temperature, have been recorded together with the window opening configurations to develop a two-fold analysis: i) the estimation of real air change rates through the transient mass balance equation method, and ii) the individual infection risk via the Wells-Riley equation. A strong statistical correlation has been found between the air change rates and the windows opening configuration by means of a window-to-volume ratio between the total opening area and the volume of the classroom, which has been used to estimate the individual infection risk. Results show that the European Standard recommendation for air renewal could be achieved by a window opening area of at least 1.5 m2, in the most prevailing Italian classrooms. Furthermore, scenarios in which the infector agent is a teacher show higher individual infection risk than those in which the infector is a student. In addition, the outcomes serve school staff as a reference to ensure adequate ventilation in classrooms and keep the risk of infection under control based on the number of the students and the volume of the classroom.

In vitro evaluation on a model of blood brain barrier of idebenone-loaded solid lipid nanoparticles.

The aim of this study was to evaluate in vitro the permeation of the antioxidant agent Idebenone (IDE) loaded into solid lipid nanoparticles (SLN) across MDCKII-MDR1 cell monolayer, selected as an in vitro model of the Blood Brain Barrier (BBB). SLN were prepared using cetyl palmitate as solid lipid and different non-ionic surfactants, oleth-20, ceteth-20 and isoceth-20, by the phase inversion temperature (PIT) technique. The resulting SLN showed physiological pH and osmolarity values, a mean particle diameter in the range of 33-63 nm, a single peak in size distribution, and a zeta potential ranging from +3.14 to -2.89 mV. When incubating these SLN in Simulated Body Fluid (SBF), the particle size was maintained for all samples throughout the study. IDE permeability across MDCKII-MDR1 cell monolayers from the SLN under investigation was 0.40-0.53 fold lower than free IDE and no significant difference was observed comparing IDE permeation from all the SLN tested. It is noteworthy that IDE loading into SLN avoided the use of an organic solvent to solubilize IDE, a poor water soluble compound, allowing the parenteral administration of this drug in aqueous vehicles. Furthermore, the results of in vitro transport studies, performed using fluorescein-dextran 4000 (FD4) and diazepam (DZ) as markers of the paracellular pathway and the transcellular pathway, respectively, pointed out that IDE could permeate via a transcellular pathway. Therefore, these novel nanocarriers could be regarded as a promising strategy to design delivery systems for IDE administration to the brain, deserving further investigations under in vivo conditions.

TAAC - TMS Adaptable Auditory Control: A universal tool to mask TMS clicks.

BACKGROUND: Coupling transcranial magnetic stimulation with electroencephalography (TMS-EEG) allows recording the EEG response to a direct, non-invasive cortical perturbation. However, obtaining a genuine TMS-evoked EEG potential requires controlling for several confounds, among which a main source is represented by the auditory evoked potentials (AEPs) associated to the TMS discharge noise (TMS click). This contaminating factor can be in principle prevented by playing a masking noise through earphones. NEW METHOD: Here we release TMS Adaptable Auditory Control (TAAC), a highly flexible, open-source, Matlab®-based interface that generates in real-time customized masking noises. TAAC creates noises starting from the stimulator-specific TMS click and tailors them to fit the individual, subject-specific click perception by mixing and manipulating the standard noises in both time and frequency domains. RESULTS: We showed that TAAC allows us to provide standard as well as customized noises able to effectively and safely mask the TMS click. COMPARISON WITH EXISTING METHODS: Here, we showcased two customized noises by comparing them to two standard noises previously used in the TMS literature (i.e., a white noise and a noise generated from the stimulator-specific TMS click only). For each, we quantified the Sound Pressure Level (SPL; measured by a Head and Torso Simulator - HATS) required to mask the TMS click in a population of 20 healthy subjects. Both customized noises were effective at safe (according to OSHA and NIOSH safety guidelines) and lower SPLs with respect to standard noises. CONCLUSIONS: At odds with previous methods, TAAC allows creating effective and safe masking noises specifically tailored on each TMS device and subject. The combination of TAAC with tools for the real-time visualization of TEPs can help control the influence of auditory confounds also in non-compliant patients. Finally, TAAC is a highly flexible and open-source tool, so it can be further extended to meet different experimental requirements.

Human neutrophil peptides sputum levels in symptomatic smokers and COPD patients.

BACKGROUND AND OBJECTIVES: Human Neutrophil Peptides (HNP) are major neutrophils' products which may contribute to the airway inflammation and lung remodelling during chronic obstructive pulmonary disease (COPD). We aimed to assess whether HNP sputum concentrations could be used as indicators of airway inflammation and progression towards pulmonary functional impairment, and correlate with the degree of airways obstruction. MATERIALS AND METHODS: We measured, by ELISA tests, HNP concentrations from 37 symptomatic smokers and 34 COPD patients. All participants underwent pulmonary function tests. Sputum samples were collected at the enrolment, and 6 months after smoking cessation. Differences between groups and correlation coefficients between variables were determined using non parametric tests. RESULTS: Sputum HNP concentrations were higher in COPD patients as compared to symptomatic smokers (14 +/- 1.5 microg/ml vs 1.6 +/- 0.4 microg/ml; p < 0.0001). Among COPD patients HNP concentrations were higher in individuals with severe obstruction than in patients with mild to moderate COPD (19.9 +/- 2.3 microg/ml vs 10.3 +/- 0.8 microg/ml, p = 0.003). A negative correlation was observed between HNP levels and FEV1 (rho = -0.38, p = 0.02), and FEV1/FVC (rho = -0.42, p = 0.01). No differences were found in HNP levels before and after 6 months of smoking withdrawal (1.1 microg/ml +/- 0.3 vs 1.1 microg/ml +/- 0.3 for symptomatic smokers, p = 0.9, and 14.4 microg/ml +/- 1 vs 16 microg/ml +/- 1.1 for COPD, p = 0.6). DISCUSSION: Sputum levels of HNP may represent a marker of severity of functional impairment in COPD. Our data support the hypothesis that HNP may have a role in smoking- and COPD-related lung inflammation.

Objective estimation of body condition score by modeling cow body shape from digital images.

Body condition score (BCS) is considered an important tool for management of dairy cattle. The feasibility of estimating the BCS from digital images has been demonstrated in recent work. Regression machines have been successfully employed for automatic BCS estimation, taking into account information of the overall shape or information extracted on anatomical points of the shape. Despite the progress in this research area, such studies have not addressed the problem of modeling the shape of cows to build a robust descriptor for automatic BCS estimation. Moreover, a benchmark data set of images meant as a point of reference for quantitative evaluation and comparison of different automatic estimation methods for BCS is lacking. The main objective of this study was to develop a technique that was able to describe the body shape of cows in a reconstructive way. Images, used to build a benchmark data set for developing an automatic system for BCS, were taken using a camera placed above an exit gate from the milking robot. The camera was positioned at 3 m from the ground and in such a position to capture images of the rear, dorsal pelvic, and loin area of cows. The BCS of each cow was estimated on site by 2 technicians and associated to the cow images. The benchmark data set contained 286 images with associated BCS, anatomical points, and shapes. It was used for quantitative evaluation. A set of example cow body shapes was created. Linear and polynomial kernel principal component analysis was used to reconstruct shapes of cows using a linear combination of basic shapes constructed from the example database. In this manner, a cow's body shape was described by considering her variability from the average shape. The method produced a compact description of the shape to be used for automatic estimation of BCS. Model validation showed that the polynomial model proposed in this study performs better (error=0.31) than other state-of-the-art methods in estimating BCS even at the extreme values of BCS scale.

A predictive micromechanically-based model for damage and permanent deformations in copolymer sutures.

An effective description of the mechanical behavior of biodegradable copolymers suture threads requires the analysis of their response under cyclic loading and the prediction of the fundamental damage and residual stretches effects. In this paper we propose a micromechanically-based model adopting a new form of Worm Like Chain free energy for the copolymer chains, which takes care of the insurgence of residual stretches on the basis of a rigorous statistical mechanics result. Under the affinity hypothesis we subsequently derive the macroscopic response of the material. The obtained model has a clear physical interpretation and depends on a small number of parameters, which can be fitted by a simple uniaxial test. The effectiveness of the theoretical results has then been verified by performing cyclic tests on Monocryl® monofilament sutures and showing the ability of the model in predicting with high accuracy the history dependence, the damage and permanent deformations in the obtained response.

Damage, self-healing, and hysteresis in spider silks.

In this article, we propose a microstructure-based continuum model to describe the material behavior of spider silks. We suppose that the material is composed of a soft fraction with entropic elasticity and a hard, damageable fraction. The hard fraction models the presence of stiffer, crystal-rich, oriented regions and accounts for the effect of softening induced by the breaking of hydrogen bonds. To describe the observed presence of crystals with different size, composition, and orientation, this hard fraction is modeled as a distribution of materials with variable properties. The soft fraction describes the remaining regions of amorphous material and is here modeled as a wormlike chain. During stretching, we consider the effect of bond-breaking as a transition from the hard- to the soft-material phase. As we demonstrate, a crucial effect of bond-breaking that accompanies the softening of the material is an increase in contour length associated with chains unraveling. The model describes also the self-healing properties of the material by assuming partial bond reconnection upon unloading. Despite its simplicity, the proposed mechanical system reproduces the main experimental effects observed in cyclic loading of spider silks. Moreover, our approach is amenable to two- or three-dimensional extensions and may prove to be a useful tool in the field of microstructure optimization for bioinspired materials.

Unveiling the influence of device stiffness in single macromolecule unfolding.

Single-molecule stretching experiments on DNA, RNA, and other biological macromolecules opened up the possibility of an impressive progress in many fields of life and medical sciences. The reliability of such experiments may be crucially limited by the possibility of determining the influence of the apparatus on the experimental outputs. Here we deduce a model that let us analytically evaluate such influence, fundamental for the interpretation of Single Molecule Force Spectroscopy experiments and intermolecular interactions phenomena. As we show, our model is coherent with previous numerical results and quantitively reproduce AFM experimental tests on titin macromolecules and P-selectin with variable probe stiffnesses.

A prospective study of the effects of carbocysteine lysine salt on frequency of exacerbations in COPD patients treated with or without inhaled steroids.

OBJECTIVE: COPD is one of the major causes of morbidity and mortality worldwide and represents one of the most important issues for public health. Frequent exacerbations induce a faster decline in lung function and poorer quality of life, increase mortality, and have a socio-economic impact with a high burden in terms of resources and healthcare costs. The clinical trials evaluated the effect of mucolytics in COPD and showed that the long-term carbocysteine, associated with bronchodilators, anticholinergics, and steroids, reduces the frequency of exacerbations and improves the quality of life. PATIENTS AND METHODS: The aim of this prospective real-life study was to evaluate the long-term impact on exacerbations (at 1 year) in COPD patients treated with carbocysteine lysine salt (single dose of 2.7 g once a day) in addition to background therapy with or without inhaled steroids. RESULTS: In a total of 155 evaluable patients, our study showed that the addition of a single dose of carbocysteine lysine salt to background therapy determines a statistically significant reduction of the average number of exacerbations vs. the number observed in the previous year (from 1.97±0.10 to 1.03±0.11; p<0.01), irrespective of treatment with or without inhaled steroids. In particular, in patients with ≥2 exacerbations in the previous year, the addition of carbocysteine lysine salt resulted in a statistically significant reduction in the exacerbations rate from 69% to 33% and from 58% to 25%, respectively (p<0.01) in patients with or without inhaled steroids. CONCLUSIONS: In summary, our data highlighted the efficacy of long-term administration of a single daily dose of carbocysteine lysine salt (2.7 g/day) in reducing the number and rate of exacerbations in COPD patients, independently from the use of inhaled steroids.

The POLARBEAR Fourier transform spectrometer calibrator and spectroscopic characterization of the POLARBEAR instrument.

We describe the Fourier Transform Spectrometer (FTS) used for in-field testing of the POLARBEAR receiver, an experiment located in the Atacama Desert of Chile which measures the cosmic microwave background (CMB) polarization. The POLARBEAR-FTS (PB-FTS) is a Martin-Puplett interferometer designed to couple to the Huan Tran Telescope (HTT) on which the POLARBEAR receiver is installed. The PB-FTS measured the spectral response of the POLARBEAR receiver with signal-to-noise ratio >20 for ∼69% of the focal plane detectors due to three features: a high throughput of 15.1 sr cm2, optimized optical coupling to the POLARBEAR optics using a custom designed output parabolic mirror, and a continuously modulated output polarizer. The PB-FTS parabolic mirror is designed to mimic the shape of the 2.5 m-diameter HTT primary reflector, which allows for optimum optical coupling to the POLARBEAR receiver, reducing aberrations and systematics. One polarizing grid is placed at the output of the PB-FTS and modulated via continuous rotation. This modulation allows for decomposition of the signal into different harmonics that can be used to probe potentially pernicious sources of systematic error in a polarization-sensitive instrument. The high throughput and continuous output polarizer modulation features are unique compared to other FTS calibrators used in the CMB field. In-field characterization of the POLARBEAR receiver was accomplished using the PB-FTS in April 2014. We discuss the design, construction, and operation of the PB-FTS and present the spectral characterization of the POLARBEAR receiver. We introduce future applications for the PB-FTS in the next-generation CMB experiment, the Simons Array.

Colchicine, cyclophosphamide and prednisone in the treatment of mild-moderate idiopathic pulmonary fibrosis: comparison of three currently available therapeutic regimens.

STUDY OBJECTIVES: In this study we evaluated the role of three currently available therapeutic regimens in the treatment of early stages of idiopathic pulmonary fibrosis (IPF). PATIENTS: The study population consisted of 57 consecutive suspected individuals with IPF. Patients with interstitial pneumonias other than IPF and subjects with advanced disease or contraindication to therapy were excluded. We evaluated 30 subjects with mild-moderate IPF, homogeneous baseline characteristics and prognostic parameters that were assigned to 3 treatment regimens: group 1 (n = 11): prednisone 1 mg/kg/ day; group 2 (n = 9): prednisone 0.5 mg/kg/day plus cyclophosphamide 100 mg/day; group 3 (n = 10): prednisone 0.5 mg/kg/day plus colchicine 1 mg/day. We analysed response to therapy by analysis of a clinical-radiographic-physiologic (CRP) score before treatment and at 6 months intervals for 18 months. Side effects and three years survival rate were also investigated. RESULTS: Although our study was performed in a subset of patients with early disease's stages, these data showed that none of the regimens was able to interfere with IPF's course. However treatment with colchicine plus prednisone resulted in fewer side effects and re-evaluation parameters showed a significant decrease of dyspnoea (p < 0.01). No significant differences were observed in survival rate among the three groups. CONCLUSIONS: None of the regimens analyzed was effective even in the treatment of the early stages of IPF. The association colchicine/corticosteroids could be considered a safe and not expensive regimen that may be used in the treatment of IPF, especially in patients who have experienced adverse effects from immunosuppressive agents, while waiting for newer therapeutic strategies.