The solid-form landscape of urea was explored using full interaction maps (FIMs) and data from the CSD to develop optimum protocols for synthesizing co-crystals of urea. As a result, 49 of the 60 ...attempted reactions produced new co-crystals, and the crystal structures of four of these are presented. Moreover, the goal of reducing the solubility and lowering the hygroscopicity of the parent compound was achieved, which in turn offers new opportunities for application as a slow-release fertilizer with limited hygroscopicity, thereby reducing many current problems of transport, handling, and storage of urea.
•Three cocrystals of 3,4-dihydroxyphenylactic acid with nicotinamide, caprolactam and sarcosine (DHPAA−NIC, DHPAA−CPR and DHPAA−SAR) were prepared and characterized for the first time.•DHPAA−NIC, ...DHPAA−CPR and DHPAA−SAR significantly enhanced the phase stability of DHPAA raw material.•DHPAA−NIC and DHPAA−CPR had lower hygroscopicity than DHPAA raw material.
Cocrystal technology is a collaborative strategy for improving the physicochemical properties of active pharmaceutical ingredients. To overcome the obstacles of phase instability and high hygroscopicity of 3,4-dihydroxyphenylactic acid (DHPAA), three new cocrystals of DHPAA with nicotinamide (NIC), caprolactam (CPR) and sarcosine (SAR) were designed and synthesized for the first time, which were characterized using single crystal X-ray diffraction, powder X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis and infrared spectroscopy technologies. The results of stability test and hygroscopicity study demonstrated that DHPAA−NIC, DHPAA−CPR and DHPAA−SAR exhibited a remarkable improvement in the phase stability of DHPAA, meanwhile, DHPAA−NIC and DHPAA−CPR also displayed reduced hygroscopicity compared to DHPAA. This study can provide new directions of improving the druggability of DHPAA through cocrystallization.
Three cocrystals of 3,4-dihydroxyphenylactic acid with nicotinamide, caprolactam and sarcosine were designed and synthesized for the first time to improve the phase stability and reduce the hygroscopicity. The results showed that the stability of the three cocrystals was significantly improved and DHPAA−NIC and DHPAA−CPR had lower hygroscopicity compared to raw material. Display omitted
In recent decades, bioactive peptides have become an emerging field of interest in the scientific community as well as the food, pharmaceutical, and cosmetics industries. A growing body of research ...indicates that consumption of bioactive peptides may play a vital role in health through their broad spectrum of bioactivity such as antioxidant, antihypertensive, antimicrobial, anti-inflammatory, immunomodulatory, and anti-proliferative activities. In addition, bioactive peptides can be used as food preservatives due to their antimicrobial and antioxidant activities. However, some factors limit their nutraceutical and commercial applications, including easy chemical degradation (
, pH, enzymatic), food matrix interaction, low water-solubility, hygroscopicity, and potential bitter taste. Bearing that in mind, the encapsulation of bioactive peptides in different materials can help overcome these challenges. Studies have demonstrated that encapsulation of bioactive peptides increases their bioactivity, improves their stability, sensory properties, increases solubility, and decreases hygroscopicity. However, there is limited scientific evidence about the bioavailability and food matrix interactions of encapsulated peptides. Besides, the diverse colloidal systems used to encapsulate bioactive peptides have shown stability and good encapsulation efficiency. This review provides an overview of current advances in the encapsulation of bioactive peptides, considering the technology, developments, and innovations in the last lustrum.
Yacon juice powder can be used as a highly nutritious ingredient in several food preparations. To this purpose, factors such as moisture content, density, porosity and solubility should be optimized ...as they are determinant to the product's ease of reconstitution, stability and sensory quality. In this work, yacon juices with two different concentrations (8°Brix and 24°Brix), both added of egg albumin as foaming agent, were subjected to foam mat drying using different temperatures (50 °C, 60 °C and 70 °C) and thicknesses of the foam layer (0.5 cm, 1.0 cm and 1.5 cm). The resulting juice powders were assessed for color, moisture, chemical composition, water activity, solubility in water, water absorption rate, absolute and bulk densities, intragranular porosity, microstructure and hygroscopicity. The drying conditions did not affect solubility index, density, microstructure and porosity of the particles, however the temperature increase reduced moisture content, water activity and, consequently, hygroscopicity. The powders of concentrate juice resulted lighter and reddish respect to the non concentrate juices, which tended to green. The highest air temperature coupled with reduced thickness for both juices was found to be the best drying condition, yielding juice powders with low water activity and satisfactory physicochemical characteristics.
•The physical characteristics and morphology were not affected by drying conditions.•The increase in drying temperature reduced moisture content and water activity.•The powders of concentrate juice are light and reddish.•The powders of non concentrate juices tended to green.•The best drying condition was 0.5 cm and 70 °C for both juices.
Water scarcity is a ubiquitous problem with its magnitude expected to rise in the near future, and efforts to seek alternative water sources are on the rise. Harvesting water from air has intrigued ...enormous research interest among many groups with Scientific American listing this technology as the second most impactful technology that can bring about a massive change in people's lives. Though desalination offers a huge prospect in mitigating water crisis, its practicality is limited by exorbitant energy requirement. Alternatively, the air above sea water is moisture rich, with the quantity of vapor increasing at the rate of 0.41 kg m−2. Herein, a method to sustainably harvest water from this moisture rich zone is demonstrated by employing a nanoporous superhygroscopic hydrogel, which is capable of absorbing water from highly humid atmospheres by over 420% (highest) of its own weight. The desorption process from the hydrogel, occurring at 55 °C (lowest), is triggered by natural sunlight (A.M 1.5) thereby ensuing an external energy‐less water harvesting approach. The hydrogel exhibits excellent stability even after 1000 absorption/desorption cycles. Through multiple absorption/desorption cycles, it is possible to harvest over 10 L water per kg of hydrogel daily.
An efficient way of harvesting fresh water from humid air existing above open water surface enabled by a superhygroscopic hydrogel is demonstrated. This method paves a way for a futuristic membrane‐less and zero‐energy approach to desalination by pulling clean water from the sea.
The aims of this study are to fabricate hollow fiber air filters with different hydrophilicity and investigate their filtration performance against different particles under different relative ...humidity. In this study, three types of hollow fibers were prepared: a hydrophilic PAN hollow fiber, a hydrophobic PVDF hollow fiber, and a dual layer PAN/PVDF hollow fiber. The three hollow fibers were used to filtrate nano-sized NaCl (hygroscopic) and Al2O3 (non-hygroscopic) particles at RH 80% and 40%. The results showed that the filtration efficiency was not affected by RH, particle hygroscopicity and filter hydrophilicity whereas the pressure drop across membranes was influenced significantly. When filtrating NaCl particles at RH80%, a RH higher than deliquescent point of NaCl, the PAN hollow fiber had a quick pressure drop increase initially whereas the pressure drop of the PVDF hollow fiber only increased dramatically at a later stage. In contrast, the PAN/PVDF hollow fiber always displayed the lowest pressure drop increment. When filtrating Al2O3 particles at RH 80%, the PAN hollow fiber showed a higher pressure drop increment than PAN/PVDF and PVDF hollow fibers. For the filtration at RH 40%, the pressure drops of all hollow fibers were independent of particle hygroscopicity and filter hydrophilicity. Overall, the PAN/PVDF dual layer hollow fiber had the best filtration performance at all experimental conditions. The mechanisms of particle deposition at different filtration conditions have been elucidated. These findings may provide useful insights to design next-generation air filters suitable for filtrating various aerosol particles in a wide range of RH.
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•The filtration efficiency is independent of RH, particle hygroscopicity, and filter hydrophilicity.•When RH is high, hydrophobic filters have a dramatic pressure drop increment at a later stage.•When RH is high, hydrophilic filters have a quick rise in the pressure drop initially.•When RH is low, the pressure drops of filters are independent of particle hygroscopicity and membrane hydrophilicity.•The hollow fiber with a hydrophobic outer surface and hydrophilic inner surface shows the best filtration performance.
Aerosols have adverse effects on human health and air quality, changing Earth's energy balance and lead to climate change. The components of aerosol are important because of the different spectral ...characteristics. Based on the low hygroscopic and high scattering properties of organic matter (OM) in fine modal atmospheric aerosols, we develop an inversion algorithm using remote sensing to obtain aerosol components including black carbon (BC), organic matter (OM), ammonium nitrate-like (AN), dust-like (DU) components and aerosol water content (AW). In the algorithm, the microphysical characteristics (i.e. volume distribution and complex refractive index) of particulates are preliminarily separated to fine and coarse modes, and then aerosol components are retrieved using bimodal parameters. We execute the algorithm using remote sensing measurements of sun-sky radiometer at AERONET site (Beijing RADI) in a period from October of 2014 to January of 2015. The results show a reasonable distribution of aerosol components and a good fit for spectral feature calculations. The mean OM mass concentration in atmospheric column is account for 14.93% of the total and 56.34% of dry and fine-mode aerosol, being a fairly good correlation (R = 0.56) with the in situ observations near the surface layer.
•Low hygroscopic and high scattering atmospheric columnar OMs are retrieved.•Estimated OM concentrations show good correlation with in situ observations.•Columnar OM can be half of mass of dry particles in fine mode in Beijing winter.
Abstract
Air quality has greatly improved in China owing to the strict control policy enforced during the last decade. This study investigated the impact of particulate pollution control on aerosol ...hygroscopicity and cloud condensation nuclei (CCN) activity in North China based on several data sources. The mass concentration of particles with an aerodynamic diameter smaller than 2.5
µ
m (PM
2.5
) decreased by one third from the summer of 2014 to the summer of 2020 in Xinzhou (XZ). The mass fractions of aerosol chemical components in PM
2.5
also clearly changed, showing an increase in hydrophilic inorganics and a decrease in hydrophobic organics and black carbon from 2014 to 2020. Measurements of the particle number size distribution in XZ indicate that the occurrence frequency of new particle formation (NPF) events decreased significantly from 2014 to 2020, leading to a reduction in the generation of daytime ultrafine particles. The weakened NPF and increasing influence of morning and evening peak emissions modified the diurnal variations of the number concentration of condensation nuclei (
N
CN
) and CCN (
N
CCN
). The aerosol activation ratio was always higher in the summer of 2014 than in the summer of 2020. These results demonstrate that particulate pollution control can decrease
N
CN
and
N
CCN
but enhance aerosol hygroscopicity and activation ability.
Although ground-level monitoring can provide accurate PM2.5 measurements, it has limited spatial coverage and resolution. In contrast, satellite-based monitoring can provide aerosol optical depth ...(AOD) products with higher spatial resolution and continuous spatial coverage, but it cannot directly measure ground-level PM2.5 concentration. Observation-based and simulation-based approaches have been actively developed to retrieve ground-level PM2.5 concentrations from satellite AOD and sparse ground-level observations. However, the effect of aerosol characteristics (e.g., aerosol composition and size distribution) on the AOD–PM2.5 relationship is seldom considered in observation-based methods. Although these characteristics are considered in simulation-based methods, the results still suffer from model uncertainties. In this study, we propose an observation-based algorithm that considers the effect of the main aerosol characteristics. Their related effects on hygroscopic growth, particle mass extinction efficiency, and size distribution are estimated and incorporated into the AOD–PM2.5 relationship. The method is applied to quantify the PM2.5 distribution in China. Good agreements between satellite-retrieved and ground-observed PM2.5 annual and monthly averages are identified, with significant spatial correlations of 0.90 and 0.76, respectively, at 565 stations in China. The results suggest that this approach can measure large scale PM distributions with verified results that are at least as good as those from simulation-based estimations. The results also show the method's capacity to identify PM2.5 spatial distribution with high-resolution at national, regional, and urban scales and to provide useful information for air pollution control strategies, health risk assessments, etc.
•An AOD–PM2.5 algorithm is developed and evaluated based solely on observation (OBSM).•Impact on light extinction from aerosol characteristic is first fitted in the OBSM.•Surface PM2.5 (1km) over China is estimated by the proposed OBSM.•High spatial r (0.9) is found between retrieved and observed PM2.5 at 565 stations.
In purpose of studying the effects of different positions of salt/cocrystal formers acidic groups on the physicochemical properties of pharmaceutical salt/cocrystal, two novel pharmaceutical salts of ...palmatine (PLT), PLT-PA and PLT-IPA, were synthesized based on the summary of the structures and properties of the pharmaceutical salts/cocrystals of palmatine chloride, using phthalic acid (PA) and isophthalic acid (IPA) as model compounds. Single crystal X-ray diffraction analysis shows that PLT-PA and PLT-IPA have similar columnar supramolecular chain structure formation, which is assembled by supramolecular synthons R44 (18) and R66 (22), respectively. This may be due to the fact that the two carboxy groups from IPA are in allotropic position and allow water molecules to enter the lattice and provide hydrogen donors to form larger ring motif, and the lattice water and other molecules in PLT-IPA jointly support the three-dimensional crystal structure. The results of solubility measurements and hygroscopicity tests showed that the order of solubility of PLT and its salts was PLT-IPA > PLTCl > PLT-PA, and the order of hygroscopicity was PLT-IPA > PLTCl > PLT-PA. Compared to PLTCl, PLT-PA has better against hygroscopic, while PLT-IPA has increased moisture absorption, but correspondingly has higher water solubility. This may be related to the involvement of water molecules in the formation of the motif during cocrystallization of PLT and IPA. This conclusion is also supported by theoretical calculation. Furthermore, since PLT-PA and PLT-IPA were synthesized and cocrystallized in the same conditions, the role of positional isomerism of carboxy groups in the construction of crystals is of particular importance. This work shows that positional isomerism of –COOH on salt/cocrystal formers may lead to changes in crystal structure, which in turn affects changes in physicochemical properties of the pharmaceutical. This provides a theoretical basis for the design and prediction of drug salts/cocrystals with targeted physicochemical properties.
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•Two new pharmaceutical salts of PLT with phthalic and isophthalic acids were obtained.•Positional isomerism of –COOH results in two salts with opposite solubility and hygroscopicity.•Lattice water is responsible for the conformational differences of palmatine.
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