This work presents an experimental investigation of water adsorption in metal–organic frameworks (MOFs) at room temperature and up to 90% relative humidity. Structural degradation of the materials ...after regeneration is analyzed via powder X-ray diffraction (PXRD) and nitrogen adsorption measurements. MOFs with open metal sites are quite hydrophilic but appear to maintain their structure according to PXRD. However, significant surface area loss indicates that decomposition is occurring and is likely an attribute of oxygen presence during the regeneration procedure. Materials with copper paddle-wheel (HKUST-1), 5-coordinated magnesium (Mg MOF-74), and 7-coordinated zirconium (UiO-66(-NH2)) maintain good structural stability, while Zn-COOH containing MOFs (DMOF-1; DMOF-1-NH2; UMCM-1) undergo complete loss of crystallinity.
A mesoporous metal−organic framework (MOF) material, UMCM-1, has been synthesized and characterized using N2 adsorption, powder X-ray diffraction, scanning electron microscopy, and Fourier transform ...infrared techniques. A detailed experimental study has been made of the adsorption of pure methane, hydrogen, carbon dioxide, oxygen, and nitrogen at various temperatures (298−338 K) and pressures (up to 25 bar). Multitemperature isotherms were modeled using the Dubinin−Astakhov equation to obtain useful thermodynamic properties including adsorption potential characteristic curves and isosteric heats of adsorption. Results are compared with mesoporous carbons and silicas. Large-pore materials are shown to exhibit relatively high heats of adsorption for CO2 when open metal sites are present. This phenomenon is not observed for methane, which indicates the importance of the CO2 quadrupole in influencing binding strength. Adsorption results for N2 and O2 show that selectivities in MOFs can be manipulated by the presence or absence of open metal sites. UMCM-1 and MOF-177 show a slight preference for O2 over N2. However, open metal site MOFs such as Cu-BTC show the opposite adsorption preference, which is similar to zeolite selectivities. This experimental study reveals interesting adsorption information about a novel mesoporous MOF within the context of other MOFs and traditional mesoporous adsorbents. These results can be used to advance the development of structure−property relationships for metal−organic frameworks.
By combining metal‐organic frameworks (MOFs) with colloidal crystals, the challenge of signal transduction in response to molecular sorption by MOF materials can be met for sensing applications. ...HKUST‐1 (Cu2(BTC)3) is grown on a silica colloidal crystal thin film via a step‐by‐step technique, and the obtained MOF‐containing colloidal crystal is rapidly and reversibly responsive to vapor or gas molecules adsorbed by the MOF component.
Chiral nanotube: A flexible porous homochiral SrSi2 framework of two types of single‐stranded helical nanotubes is presented (see structure). The CuI ions in the framework can be oxidized to CuII ...through single‐crystal‐to‐single‐crystal transformation forming a new, topologically equivalent phase, accompanied by an expansion in the unit cell volume of 12.51 %.
A comprehensive scale-up procedure for amine-functionalized UiO-66 is implemented, which leads to the development of a novel flow-through metal-organic framework synthesis process. Products are ...characterized via BET modeling of N2 adsorption at 77 K and powder XRD to confirm crystal porosity and phase, respectively. Batch syntheses are conducted to examine the effects of polytetrafluoroethylene and glass vessel materials on crystal yield and quality. Intermediate samples from sealed-vessel trials at 373, 383, and 393 K are collected and characterized, which show a high degree of product consistency. Nucleation rates are determined at the same temperatures, and the Arrhenius relationship is used to predict the activation energy of nucleation, E... A continuous-flow reactive crystallization process is developed using a draft-tube type reactor. As a proof of concept, the reactor is operated for three retention times. The cumulative product, material retained within the crystallizer, and intermediate samples are collected and characterized to confirm UiO-66-NH2 production. (ProQuest: ... denotes formulae/symbols omitted.)
A comprehensive scale-up procedure for amine-functionalized UiO-66 is implemented, which leads to the development of a novel flow-through metal-organic framework synthesis process. Products are ...characterized via BET modeling of N2 adsorption at 77 K and powder XRD to confirm crystal porosity and phase, respectively. Batch syntheses are conducted to examine the effects of polytetrafluoroethylene and glass vessel materials on crystal yield and quality. Intermediate samples from sealed-vessel trials at 373, 383, and 393 K are collected and characterized, which show a high degree of product consistency. Nucleation rates are determined at the same temperatures, and the Arrhenius relationship is used to predict the activation energy of nucleation, E^sub aNuc^. A continuous-flow reactive crystallization process is developed using a draft-tube type reactor. As a proof of concept, the reactor is operated for three retention times. The cumulative product, material retained within the crystallizer, and intermediate samples are collected and characterized to confirm UiO-66-NH2 production. PUBLICATION ABSTRACT
Background:
Symptomatic femoroacetabular impingement (FAI) is associated with hip pain, functional limitations, and secondary osteoarthritis. There is limited information from large patient cohorts ...defining the specific population affected by FAI. Establishing a large cohort will facilitate the identification of “at-risk” patients and will provide a population for ongoing clinical research initiatives. The authors have therefore established a multicenter, prospective, longitudinal cohort of patients undergoing surgery for symptomatic FAI.
Purpose:
To report the clinical epidemiology, disease characteristics, and contemporary surgical treatment trends in North America for patients with symptomatic FAI.
Study Design:
Cross-sectional study; Level of evidence, 3.
Methods:
Upon approval of the institutional review boards at 8 institutions, 12 surgeons enrolled consecutive patients undergoing surgical intervention for symptomatic FAI. Patient demographics, physical examination data, radiographic data, diagnoses, operative data, and standardized patient-reported outcome measures were collected. The first 1130 cases are summarized in this study.
Results:
A total of 1076 consecutive patients (1130 hips) were enrolled; 55% (n = 622) were female, and 45% (n = 508) were male, with an average age of 28.4 years and average body mass index (BMI) of 25.1. Demographics revealed that 88% of patients who were predominantly treated for FAI were white, 19% reported a family history of hip surgery, 47.6% of hips had a diagnosis of cam FAI, 44.5% had combined cam/pincer FAI, and 7.9% had pincer FAI. Preoperative clinical scores (pain, function, activity level, and overall health) indicated a major dysfunction related to the hip. Surgical interventions were arthroscopic surgery (50.4%), surgical dislocation (34.4%), reverse periacetabular osteotomy (9.4%), limited open osteochondroplasty with arthroscopic surgery (5.8%), and limited open by itself (1.5%). More than 90% of the hips were noted to have labral and articular cartilage abnormalities at surgery; femoral head-neck osteochondroplasty was performed in 91.6% of the surgical procedures, acetabular rim osteoplasty in 36.7%, labral repair in 47.8%, labral debridement in 16.3%, and acetabular chondroplasty in 40.1%.
Conclusion:
This multicenter, prospective, longitudinal cohort is one of the largest FAI cohorts to date. In this cohort, FAI occurred predominantly in young, white patients with a normal BMI, and there were more female than male patients. The disease pattern of cam FAI was most common. Contemporary treatment was predominantly arthroscopic followed by surgical hip dislocation.
