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In the last decades, a variety of nuclear magnetic resonance (NMR) techniques have been applied with success in the field of advanced functional materials, including the important area of drug delivery. In such field, solid-state NMR (SSNMR) is an irreplaceable tool in the arsenal of characterization techniques, offering unique and comprehensive perspectives for the description of chemical structure, spatial connectivity and interfacial phenomena of solid dosage forms. This review focuses on the widespread applications of SSNMR in drug delivery field, an overview of selected case studies is provided, together with possible developments.

Development of an efficient and green adsorbent is of great significance for phosphorus removal and recovery from eutrophic water. This work prepared an eggshell modified biochar (ESBC) by co-pyrolysis of eggshells and corn stalk. ESBC exhibited an excellent performance for phosphorus adsorption over a wide pH range (5-13), and achieved a maximum adsorption of 557.0 mg P/g. The adsorption process was well fitted by pseudo-second-order model (R

The understanding of drug-carrier interactions is essential for the design and applications of metal-organic framework (MOF)-based drug delivery systems. While such drug-carrier interactions can be fundamentally different for MOFs with or without defects. In this work, we revealed that the defects in MOFs play a key role in the loading of many pharmaceuticals with phosphate or phosphonate groups. The host-guest interaction is dominated by the Coulombic attraction between phosphate/phosphonate groups and defect sites and it strongly enhances the loading capacity. For similar molecules without a phosphate/phosphonate group or for MOF without defects, the loading capacity is greatly reduced. We employed solid-state nuclear magnetic resonance (NMR) and molecular simulations to elucidate the drug-carrier interaction mechanisms. Through a synergistic combination of experimental and theoretical analyses, the docking conformations of pharmaceuticals at the defects have been revealed.

Crystalline materials are often considered to have rigid periodic lattices while soft materials are associated with flexibility and non-periodicity. The continuous evolution of metal-organic frameworks (MOFs) has erased the boundaries between these two distinct conceptions. Flexibility, disorder and defects have been found to be abundant in MOF materials with imperfect crystallinity, and their intricate interplay is poorly understood due to the limited strategies for characterizing disordered structures. Here, we apply advanced nuclear magnetic resonance (NMR) spectroscopy to elucidate the mesoscale structures in a defective MOF with a partially disordered lattice. We show that engineered defects can tune the degree of lattice flexibility by combining both ordered and disordered compartments. The one-dimensional alignment of defects is the key for the reversible topological transition.

The flexibility in structural design of organic semiconductors endows organic solar cells (OSCs) not only great function-tunabilities, but also high potential toward practical application. In this work, simple non-fused-ring electron acceptors are developed through two-step synthesis from single aromatic units for constructing efficient OSCs. With the assistance of non-covalent interactions, these rotatable non-fused acceptors (in solution) allow transiting into planar and stackable conformation in condensed solid, promoting acceptors not only feasible solution-processability, but also excellent film characteristics. As results, decent power conversion efficiencies of 10.27% and 13.97% can be achieved in single and tandem OSCs consisting of simple solution-cast blends, in which the fully unfused acceptors exhibit exceptionally low synthetic complexity index. In addition, the unfused acceptor and its based OSCs exhibit promising stabilities under continuous illumination. Overall, this work reveals valuable insights on the structural design of simple and effective electron acceptors with great practical perspectives., Non-fullerene electron acceptors have pushed the efficiency of organic solar cells up to 15% but they all contain fused rings and are inconvenient to synthetic access. Here Yu et al. develop fully unfused acceptors featuring non-covalent intramolecular interactions, high efficiencies and high stability.

Metal-organic frameworks (MOFs) are porous crystalline materials with promising applications in molecular adsorption, separation, and catalysis. It has been discovered recently that structural defects introduced unintentionally or by design could have a significant impact on their properties. However, the exact chemical composition and structural evolution under different conditions at the defects are still under debate. In this study, we performed multidimensional solid-state nuclear magnetic resonance (SSNMR) coupled with computer simulations to elucidate an important scenario of MOF defects, uncovering the dynamic interplay between residual acetate and water. Acetate, as a defect modulator, and water, as a byproduct, are prevalent defect-associated species, which are among the key factors determining the reactivity and stability of defects. We discovered that acetate molecules coordinate to a single metal site monodentately and pair with water at the neighboring position. The acetates are highly flexible, which undergo fast libration as well as a slow kinetic exchange with water through dynamic hydrogen bonds. The dynamic processes under variable temperatures and different hydration levels have been quantitatively analyzed across a broad time scale from microseconds to seconds. The integration of SSNMR and computer simulations allows a precision probe into defective MOF structures with intrinsic dynamics and disorder.

Pharmaceutical amorphous solid dispersions, a multicomponent system prepared by dispersing drug substances into polymeric matrix via thermal and mechanical processes, represent a major platform to deliver the poorly water-soluble drug. Microscopic properties of drug-polymer contacts play mechanistic roles in manipulating long-term physical stability as well as dissolution profiles. Although solid-state nuclear magnetic resonance has been utilized as an indispensable tool to probe structural details, previous studies are limited to ex situ characterizations. Our work provides likely the first documented example to investigate comelting of ketoconazole and polyacrylic acid, as a model system, in an in situ manner. Their physical mixture is melted and mixed in the solid-state nuclear magnetic resonance rotor under magic angle spinning at up to approximately 400 K. Critical structural events of molecular miscibility and interaction have been successfully identified. These results design and evaluate the instrumental and experimental protocols for real-time characterizations of the comelting of pharmaceutical materials.

Purpose To investigate the prevalence and visual acuity (VA) outcomes of cataract surgery in rural populations throughout China. Design Population-based, cross-sectional study. Participants Forty-five thousand seven hundred forty-seven adults 50 years of age and older. Methods Geographically defined cluster sampling was used in randomly selecting a cross-section of residents from a representative rural county within each of 9 provinces in mainland China. Participants underwent VA measurements, refraction, and a slit-lamp examination at local examination sites; those with previous cataract surgery were queried as to the year and type of surgical facility. Surgical procedure and evidence of surgery complications were noted during the examination. The principal cause of visual impairment was identified for eyes with VA of 20/40 or worse. Main Outcome Measures Cataract surgery procedure, presenting and best-corrected distance VA, and causes of visual impairment. Results Of 50 395 enumerated eligible persons, 45 747 (90.8%) were examined and tested for VA. The overall prevalence of cataract surgery was 2.09%. Surgical coverage among those with VA worse than 20/200 in both eyes because of cataract was 35.7%. Unoperated cataract was associated with older age, female gender, lack of education, and geographic area (province). Among the 1174 cataract-operated eyes, 31.1% had presenting VA of 20/32 or better, 15.4% had presenting VA of 20/40 to 20/63, 30.0% had presenting VA worse than 20/63 to 20/200, and 23.5% had presenting VA worse than 20/200. With best correction, the percentages were 57.6%, 6.2%, 18.5%, and 17.7%, respectively. Posterior capsule opacification, refractive error, and retinal disorders were the main causes in cataract-operated eyes with VA worse than 20/63. Conclusions Two thirds of those with bilateral visual impairment or blindness because of cataract remain in need of sight-restoring surgery. Posterior capsule opacification and refractive error, both readily amenable to treatment, were common in cataract-operated eyes. Sustained government efforts to provide access to affordable modern cataract surgery with a greater emphasis on postoperative follow-up and the quality of VA outcomes are needed. Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Identifying the shortcomings of traditional centralized workflow architecture, this paper describes a preliminary attempt at using a peer-to-peer (P2P)-based multi-agent framework for decentralized grid workflow management in semantic grid enabled collaborative design. A decentralized, scalable semantic service registry is laid out in the P2P network for semantic discovery of distributed, heterogeneous grid services with multi-agent support. The service-oriented, decentralized problem solving strategy for grid workflow construction makes it possible for the decentralized peer agents to utilize the formal semantics to interact and cooperate with each other to support the users in constructing the grid workflow of a complex engineering design process from widely dispersed multidisciplinary design resources effectively. A prototype system is built and validated with an illustrative example from metal stamping industry to demonstrate the feasibility of the proposed approach.

To investigate the prevalence and visual acuity (VA) outcomes of cataract surgery in rural populations throughout China.Population-based, cross-sectional study.Forty-five thousand seven hundred forty-seven adults 50 years of age and older.Geographically defined cluster sampling was used in randomly selecting a cross-section of residents from a representative rural county within each of 9 provinces in mainland China. Participants underwent VA measurements, refraction, and a slit-lamp examination at local examination sites; those with previous cataract surgery were queried as to the year and type of surgical facility. Surgical procedure and evidence of surgery complications were noted during the examination. The principal cause of visual impairment was identified for eyes with VA of 20/40 or worse.Cataract surgery procedure, presenting and best-corrected distance VA, and causes of visual impairment.Of 50 395 enumerated eligible persons, 45 747 (90.8%) were examined and tested for VA. The overall prevalence of cataract surgery was 2.09%. Surgical coverage among those with VA worse than 20/200 in both eyes because of cataract was 35.7%. Unoperated cataract was associated with older age, female gender, lack of education, and geographic area (province). Among the 1174 cataract-operated eyes, 31.1% had presenting VA of 20/32 or better, 15.4% had presenting VA of 20/40 to 20/63, 30.0% had presenting VA worse than 20/63 to 20/200, and 23.5% had presenting VA worse than 20/200. With best correction, the percentages were 57.6%, 6.2%, 18.5%, and 17.7%, respectively. Posterior capsule opacification, refractive error, and retinal disorders were the main causes in cataract-operated eyes with VA worse than 20/63.Two thirds of those with bilateral visual impairment or blindness because of cataract remain in need of sight-restoring surgery. Posterior capsule opacification and refractive error, both readily amenable to treatment, were common in cataract-operated eyes. Sustained government efforts to provide access to affordable modern cataract surgery with a greater emphasis on postoperative follow-up and the quality of VA outcomes are needed.The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Purpose Describe the prevalence of visual impairment/blindness among older adults in rural populations in China. Design Population-based, cross-sectional study. Participants We evaluated 45 747 adults ≥50 years of age. Methods Geographically defined cluster sampling was used in randomly selecting a cross-section of residents from a representative rural county within each of 9 provinces in mainland China. Participants were enumerated through village registers followed by door-to-door household visits. Eligible persons were invited to local examination sites for visual acuity (VA) testing and eye examination. Main Outcome Measures Presenting and best-corrected distance VA. Results Of 50 395 enumerated eligible persons, 45 747 (90.8%) were examined and tested for VA. The prevalence of presenting visual impairment Conclusions Visual impairment and blindness are important public health problems in rural China, with significant regional variations in prevalence. Blindness prevention programs targeting the rural elderly should be expanded, particularly in areas with limited access and affordability of eye care services. Special emphasis should be given to reaching women and those without education. Greater attention should also be given to correction of refractive error. Financial Disclosure(s) The authors have no proprietary or commercial interest in any of the materials discussed in this article.