Prediction of the roughness coefficient for drainage pipelines with sediments using GA-BPNN.

Accurate prediction of the roughness coefficient of sediment-containing drainage pipes can help engineers optimize urban drainage systems. In this paper, the variation of the roughness coefficient of circular drainage pipes containing different thicknesses of sediments under different flows and slopes was studied by experimental measurements. Back Propagation Neural Network (BPNN) and Genetic Algorithm-Back Propagation Neural Network (GA-BPNN) were used to predict the roughness coefficient. To explore the potential of artificial neural networks to predict the roughness coefficient, a formula based on drag segmentation was established to calculate the roughness coefficient. The results show that the variation trend of the roughness coefficient with flow, hydraulic radius, and Reynolds number is consistent. With the increase of the three parameters, the roughness coefficient decreases overall. Compared to the traditional empirical formula, the BPNN model and the GA-BPNN model increased the determination factors in the testing stage by 3.47 and 3.99%, respectively, and reduced the mean absolute errors by 41.18 and 47.06%, respectively. The study provides an intelligent method for accurate prediction of sediment-containing drainage pipes roughness coefficient.

Prognosis of traumatic spinal cord injury in children: Follow-up of 86 patients.

PURPOSE: The long-term situation of children with spinal cord injury (SCI) was investigated, and suggestions for helping them better return to the society were provided. METHODS: SCI patients less than 18 years old hospitalized in Beijing Boai Hospital from January 2011 to December 2020 were retrospectively analyzed. Information including motor function, complications, characteristic changes, self-care abilities, school attendance and social participation were collected by telephone interview and electronic questionnaire. All the answers were statistically analyzed. RESULTS: A total of 86 cases were enrolled, 77 girls and 9 boys, with a median injury age of 6 years and 2 months. The follow-up time was 3-130 months. The main cause of trauma in these children was sport injury (66.3%), the thoracic spinal cord was involved the most (91.9%), and complete SCIs accounted for the majority (76.7%). In terms of complications, children with complete SCIs were more likely to have urinary incontinence, constipation and characteristic changes (p < 0.05); whereas the incomplete SCIs often have spasticity (p < 0.05). As to the daily living abilities, children with incomplete lumbar SCIs were more capable to accomplish personal hygiene, transfer, and bathing independently than those with complete injuries, or cervical/thoracic SCIs, respectively (p < 0.05). Moreover, children older than 9 years care more able to dress and transfer independently than the youngers (p < 0.05). Wheelchair users accounted for 84.9% and more than half of them were able to propel wheelchair independently, and those who move passively in wheelchairs were mostly introverted kids (p < 0.05). Almost all (93.8%) children with incomplete injuries were able to walk independently. Most (79.1%) children continued to attending school, and 41.9% participated in interest classes. Unfortunately, 67.4% of the children spent less time playing with their peers than before the injury. CONCLUSION: SCIs impair physical structures and function of children, affect their independence in daily living, and restrict school attendance and social interaction. Comprehensive rehabilitation after injury is a systematic work. Medical staff and caregivers should not only pay attention to neurological function, but also help them improve self-care abilities. It is also important to balance rehabilitation training and school work and social participation.

Effect of blocked sediments on flow characteristics and associated backwater effect in drainage pipes.

The study of hydraulic characteristics of water flow affected by blocked sediment is vital to assess discharge capacity in pipes with sediment sand to understand the process of pollutant and fine sand aggregation. The aim of this paper is to study the blocking effect of permeable sediments on non-full flow in circular pipe and to analyze hydraulic characteristics with backwater. Experiments and numerical simulations were performed and the porous media model is used to simulate the flow in permeable blocked sediments. To evaluate the degree of congestion, the backwater ratio ß is proposed. The backwater ratio is positively proportional to blocked sediment height and inversely proportional to blocked sediment particle size and flow value. Cross-sectional velocity in the backwater zone decreases significantly and tends to be uniform as backwater ratio increases. Furthermore, the development of secondary flows and velocity distributions influenced by backwater height is discussed. The dimensionless shear velocity in backwater zone shows an exponential decrease as the backwater ratio increases, which greatly increases the possibility of further sediment deposition.

A Series of Functionalized Zirconium Metal-Organic Cages for Efficient CO2/N2 Separation.

Global warming associated with CO2 emission has led to frequent extreme weather events in recent years. Carbon capture using porous solid adsorbents is promising for addressing the greenhouse effect. Herein, we report a series of robust metal-organic cages (MOCs) featuring various functional groups, such as methyl and amine groups, for CO2/N2 separation. Significantly, the amine-group-functionalized MOC-QW-3-NH2 displays the best selective CO2 adsorption performance, as confirmed by single-component adsorption and transient breakthrough experiments. The distinct CO2 adsorption mechanism has been well studied via theoretical calculations, confirming that the amine groups play a vital role for efficiently selective CO2 adsorption resulting from hierarchical adsorbate-framework interaction.

Assessment of safety margin after microwave ablation of stage I NSCLC with three-dimensional reconstruction technique using CT imaging.

OBJECTIVE: To assess the ablative margin of microwave ablation (MWA) for stage I non-small cell lung cancer (NSCLC) using a three-dimensional (3D) reconstruction technique. MATERIALS AND METHODS: We retrospectively analyzed 36 patients with stage I NSCLC lesions undergoing MWA and analyzed the relationship between minimal ablative margin and the local tumor progression (LTP) interval, the distant metastasis interval and disease-free survival (DFS). The minimal ablative margin was measured using the fusion of 3D computed tomography reconstruction technique. RESULTS: Univariate and multivariate analyses indicated that tumor size (hazard ratio [HR] = 1.91, P < 0.01; HR = 2.41, P = 0.01) and minimal ablative margin (HR = 0.13, P < 0.01; HR = 0.11, P < 0.01) were independent prognostic factors for the LTP interval. Tumor size (HR = 1.96, P < 0.01; HR = 2.35, P < 0.01) and minimal ablative margin (HR = 0.17, P < 0.01; HR = 0.13, P < 0.01) were independent prognostic factors for DFS by univariate and multivariate analyses. In the group with a minimal ablative margin < 5 mm, the 1-year and 2-year local progression-free rates were 35.7% and 15.9%, respectively. The 1-year and 2-year distant metastasis-free rates were 75.6% and 75.6%, respectively; the 1-year and 2-year disease-free survival rates were 16.7% and 11.1%, respectively. In the group with a minimal ablative margin ≥ 5 mm, the 1-year and 2-year local progression-free rates were 88.9% and 69.4%, respectively. The 1-year and 2-year distant metastasis-free rates were 94.4% and 86.6%, respectively; the 1-year and 2-year disease-free survival rates were 88.9% and 63.7%, respectively. The feasibility of 3D quantitative analysis of the ablative margins after MWA for NSCLC has been validated. CONCLUSIONS: The minimal ablative margin is an independent factor of NSCLC relapse after MWA, and the fusion of 3D reconstruction technique can feasibly assess the minimal ablative margin.

Increased sagittal diameter of the vertebral arch aids in diagnosis of lumbar spondylolysis.

OBJECTIVE: To identify a diagnostic indicator of lumbar spondylolysis visible in plain X-ray films. METHODS: One hundred and seventy-two patients with low back pain who received X-ray and computerized tomography (CT) examinations were identified and studied. They were divided into three groups: the spondylosis without spondylolisthesis (SWS) group, comprising 67 patients with bilateral pars interarticularis defects at L5 and without spondylolisthesis, the isthmic spondylolisthesis (IS) group, comprising 74 patients with L5/S1 spondylolisthesis and bilateral L5 pars interarticularis defects, and the control group, comprising 31 patients with low back pain but without spondylolysis. The sagittal diameters of the vertebral arch (SDVAs) of L4 and L5 were measured in lateral X-ray image, and the differences in SDVA between L4 and L5 (DSL4-5) in each case were calculated and analyzed. RESULTS: There were no significant differences in demographic characteristics among the three groups. In the SWS and IS groups, the SDVA of L5 was significantly longer than the SDVA of L4 (p < 0.001), whereas no significant difference found in the control group (p > 0.05). DSL4-5, in which the SDVA of L4 was subtracted from the SDVA of L5, significantly differed among the three groups (p < 0.001), and the normal threshold was provisionally determined to be 1.55 mm. CONCLUSIONS: In bilateral L5 spondylolysis, the SDVA of L5 is wider than the SDVA of L4, and this difference is greater in isthmic spondylolisthesis. This sign in lateral X-rays may provide a simple and convenient aid for the diagnosis of spondylolysis.

Ischemic damage may play an important role in spinal cord injury during dancing.

STUDY DESIGN: Retrospective analysis. SETTING: China Rehabilitation Research Center, Beijing, China. OBJECTIVE: To explore possible mechanisms underlying spinal cord injury (SCI) in children caused by hyperextension of the spine while dancing. METHODS: The clinical records of 88 children with SCI (mean age, 5.97 years; age range, 4-10 years) admitted to our hospital from January 1989 to October 2019 were retrospectively reviewed. Computed tomography and magnetic resonance imaging were performed on the day of injury. The time from injury to development of paralysis, as well as post-injury activities were surveyed, while abnormal patterns on images, the range of the involved vertebrae, and the extents of edema and atrophy were assessed. RESULTS: Among the 88 patients, 6 (6.8%) were unable to move immediately after SCI, while paralysis occurred in 42, 23, and 17 patients at <30, 30-60, and >60 min after SCI, respectively. The neurological level of injury of 84 patients was between T4 and T12. On sagittal T2-weighted images (T2WIs), the longitudinal range of spinal cord edema was more than one vertebral body in 65 patients, while spinal cord atrophy below T8 was found in 40 patients. On axial T2WIs, although three patients had none, long T2 signals were found in the central gray matter of seven patients. Meanwhile, necrosis of the central area combined with the peripheral white matter was observed in 57 patients, while three patients had total involvement on a cross section. CONCLUSION: Ischemia-related damage, rather than direct trauma to the spinal cord, may play an important role in SCI due to spinal hyperextension during dancing.

Value of Chloride Clearance Test in Differential Diagnosis of Gitelman Syndrome.

Objective To investigate the value of chloride clearance test in differential diagnosis of Gitelman syndrome (GS). Methods For patients with hypokalemic metabolic alkalosis and highly suspected GS,clinical data were documented and SLC12A3 gene screening was performed as gold standard to diagnose GS. Hydrochlorothiazide (HCT) test and furosemide (FUR) test were performed according to the standard process. Baseline and maximal increasement of chloride excretion fraction (FECl,the net and relative increase measured as εFECl) were compared between patients and controls to evaluated the reaction to the corresponding diuretics. Receiver operating characteristic (ROC) curve was used to evaluate the sensitivity and specificity of HCT test in GS diagnosis. Results Totally 27 patients and 20 health controls received HCT test. Among those patients,23 were diagnosed with GS genetically. When using the net and relative εFECl to diagnose GS,the areas under the ROC curve were 0.987 (95% CI:0.963～1.000,P<0.001) and 0.984 (95%CI:0.950～1.000,P<0.001),respectively. When a reasonable cutoff value for εFECl was selected,the sensitivity and specificity were both higher than 95%. Eight patients received both HCT test and FUR test. Five of them showed decreased reaction to HCT(net εFECl≤2.86% or relative εFECl≤223%),while normal reaction to FUR.SLC12A3 mutations confirmed their GS. Three patients with blunt reaction to FUR showed normal reaction to HCT,finally they were diagnosed as BS clinically because no SLC12A3 gene mutation was detected. Conclusion Comprehensive application of HCT test and FUR test to evaluate the diuretic reaction can effectively differentiate GS and BS.

Analysis of association among clinical features and shorter leukocyte telomere length in mitochondrial diabetes with m.3243A>G mitochondrial DNA mutation.

BACKGROUND: Mitochondrial diabetes is a kind of rare diabetes caused by monogenic mutation in mitochondria. The study aimed to summarize the clinical phenotype profiles in mitochondrial diabetes with m.3243 A>G mitochondrial DNA mutation and to investigate the mechanism in this kind of diabetes by analyzing the relationship among clinical phenotypes and peripheral leukocyte DNA telomere length. METHODS: Fifteen patients with maternally inherited diabetes in five families were confirmed as carrying the m.3243 A>G mitochondrial DNA mutation. One hundred patients with type 2 diabetes and one hundred healthy control subjects were recruited to participate in the study. Sanger sequencing was used to detect the m.3243 A>G mitochondrial DNA mutation. The peak height G/A ratio in the sequence diagram was calculated. Real-time polymerase chain reaction (PCR) was used to measure telomere length. RESULTS: The patients with mitochondrial diabetes all had definite maternally inherited history, normal BMI (19.5 ± 2.36 kg/m(2)), early onset of diabetes (35.0 ± 14.6 years) and deafness. The peak height G/A ratio correlated significantly and negatively with the age at onset of diabetes (≦ 25 years, 61.6 ± 20.17%; 25-45 years, 16.59 ± 8.64%; >45 years, 6.37 ± 0.59%; p = 0.000). Telomere length was significantly shorter among patients with mitochondrial diabetes and type 2 diabetes than in the control group (1.28 ± 0.54 vs. 1.14 ± 0.43 vs. 1.63 ± 0.61; p = 0.000). However, there was no significant difference between patients with mitochondrial diabetes and those with type 2 diabetes. There was no correlation between telomere length and the peak height G/A ratio. CONCLUSION: Deafness with definite maternal inheritance and normal BMI, associated with elevated blood lactic acid and encephalomyopathy, for the most part, suggest the diagnosis of mitochondrial diabetes . The peak height G/A ratio could reflect the spectrum of age at onset of the disease. Telomere length was shorter in patients with mitochondrial diabetes and those with type 2 diabetes, which suggests that the shorter telomere length is likely involved in the pathogenesis of diabetes but is not specific for this kind of diabetes.

[Clinical manifestations, therapeutic response to tyrosinase inhibitor and RET gene activating mutation in a patient with multiple endocrine neoplasia 2B].

OBJECTIVE: To explore the clinical manifestations, therapeutic response and RET gene mutation in a patient with multiple endocrine neoplasia 2B (MEN2B) characterized by medullary thyroid carcinoma (MTC), bilateral adrenal pheochromocytoma and multiple mucosal neuromas. METHODS: The clinical features, laboratory data and radiological manifestations of this patient were collected. Genomic DNA was extracted from her peripheral blood leukocytes and her parents. Tenth to sixteenth exons of RET proto-oncogene, including the flanking regions of introns, were amplified by polymerase chain reaction (PCR). And the mutations of RET proto-oncogene were identified by direct sequencing. RESULTS: MEN-2B was diagnosed by the clinical presentations, laboratory tests and radiological findings. Gene analysis confirmed heterozygous mis-sense mutation at codon 918 in exon 16 of RET proto-oncogene in which thymine was replaced by cytosine (ATG→ACG). Her thyroid medullary carcinoma was treated by radical operations and radiotherapy. Tyrosinase inhibitor sorafenib was administered for 2 months and watery diarrhea and cough were alleviated. The drug was withdrawn because of such intolerant side effects as hair loss and painful rashes. She had a survival time of over 14 years with multiple system tumor metastases. CONCLUSIONS: The mutation analysis of RET proto-oncogene confirmed the diagnosis of MEN2B in respect of molecular genetics. For patients with advanced MTC, tyrosinase inhibitors may relieve the symptoms and provide a new therapeutic choice.

Rotation of the uterus to obtain a lower transverse incision in the posterior wall in a cesarean section: a case report and literature review.

OBJECTIVE: To demonstrate that cesarean section with a transverse incision at the lower posterior wall of the uterus is suitable for some special obstetric cases. CASE REPORT: A 35-year-old primigravida with a previous surgical history of laparoscopic myomectomy underwent elective cesarean section at 39 weeks and 2 days of gestation. During surgery, there were severe pelvic adhesions and engorged vessels on the anterior wall. Considering safety, we rotated the uterus 180 degrees and made a lower transverse incision on the posterior wall. The infant was healthy and the patient had no complications. CONCLUSIONS: A low transverse incision in the posterior uterine wall is safe and effective when the incision of the anterior wall encounters a dilemma, especially in patients with severe pelvic adhesions. We recommended this approach should be done in selected cases.

Review the progression of ovarian clear cell carcinoma from the perspective of genomics and epigenomics.

Ovarian clear cell carcinoma (OCCC) is a rare subtype of epithelial ovarian cancer with unique molecular characteristics, specific biological and clinical behavior, poor prognosis and high resistance to chemotherapy. Pushed by the development of genome-wide technologies, our knowledge about the molecular features of OCCC has been considerably advanced. Numerous studies are emerging as groundbreaking, and many of them are promising treatment strategies. In this article, we reviewed studies about the genomics and epigenetics of OCCC, including gene mutation, copy number variations, DNA methylation and histone modifications.

[Differences of blood plasma renin activity, angiotensin II and aldosterone levels in essential or secondary hypertension].

OBJECTIVE: To study on the difference of plasma renin activity (PRA), angiotensin II (Ang II), and aldosterone levels in patients with essential hypertension (EH) or primary aldosteronism (PA) or pheochromocytoma (PHEO), and to analyze the sensitivity and specificity on the diagnosis of PA among patients with hypertension with aldosterone/PRA ratio (ARR). METHODS: The plasma aldosterone, Ang II and PRA concentrations in supine and upright positions were measured by radioimmunoassay from 413 patients including idiopathic hyperaldosteronism (IHA, n = 111), aldosterone-producing adenoma (APA, n = 118), PHEO (n = 98) and EH (n = 86). ARR was calculated. RESULTS: Plasma aldosterone concentrations in both of supine and upright positions in PHEO group [374 (294, 465) pmol/L and 629 (449, 997) pmol/L] and PA group [471 (346, 632) pmol/L and 673 (499, 825) pmol/L] were higher than those in EH group [277 (224, 332) pmol/L and 427 (341, 501) pmol/L] (P < 0.01). They were also higher in APA group [576 (416, 731) pmol/L and 726 (554, 906) pmol/L] than those in IHA group [399 (313, 504) pmol/L and 609 (485, 776) pmol/L] (P < 0.01). Ang II levels in both positions were lower in PA group [43.2 (26.4, 74.4) ng/L and 60.1 (38.5, 103.6) ng/L] than in EH group [56.7 (43.3, 78.9) ng/L and 84.3 (61.3, 108.4) ng/L] or PHEO group [54.3 (29.9, 101.5) ng/L and 102.8 (49.9, 167.0) ng/L] (all P values < 0.01), and there was no difference between IHA and APA group (P > 0.05). The PRA level in both positions of each group were PHEO group [0.3 (0.2, 1.0) µg · L(-1) · h(-1) and 1.4 (0.6, 3.4) µg · L(-1) · h(-1)] > EH group [0.2 (0.1, 0.4) µg · L(-1) · h(-1) and 0.6 (0.4, 1.0) µg · L(-1) · h(-1)] (P < 0.01) > PA group [0.1 (0.1, 0.1) µg · L(-1) · h(-1) and 0.2 (0.1, 0.3) µg · L(-1) · h(-1)] (P < 0.01), and APA group [0.1 (0.1, 0.1) µg · L(-1) · h(-1) and 0.1 (0.1, 0.3) µg · L(-1) · h(-1)] < IHA group [0.1 (0.1, 0.2) µg · L(-1) · h(-1) and 0.2 (0.1, 0.3) µg · L(-1) · h(-1)] (supine P < 0.01; upright P < 0.05). APA was divided into 2 types with renin-Ang II-responsive APA (n = 26) and unresponsive APA (n = 92). The plasma aldosterone concentration was lower in supine position but higher in upright position in renin-Ang II-responsive APA than in unresponsive APA patients. ARR in upright was higher in PA group (P < 0.01) but lower in PHEO group (P < 0.05) compared with EH. ARR was higher in APA than in IHA (P < 0.01). The sensitivity and specificity of ARR as 40 (aldosterone unit: ng/dl; PRA unit: µg · L(-1) · h(-1); its value should multiply 27.7 when transferred to pmol/L, simili) were 93% and 76%, respectively. CONCLUSION: The levels of PRA, Ang II and aldosterone from patients with EH, PA and PHEO are significant different. ARR as 40 in upright position could be used for PA screening cutoff point.

Clinical characteristics of pediatric traumatic spinal cord injury in China: A single center retrospective study.

OBJECTIVE: To investigate the clinical characteristics of children with traumatic spinal cord injury (SCI) admitted to a research rehabilitation center between 2011 and 2020, with a view to generate crucial data for understanding and prevention of pediatric traumatic SCI. DESIGN: Retrospective cohort study. SETTING: The National Rehabilitation Research Center of China, Beijing, China. PARTICIPANTS: Medical records and imaging data of children with traumatic SCI admitted to the rehabilitation research center from 2011 to 2020. INTERVENTIONS: Not applicable. OUTCOME MEASURES: Data on age, sex, cause of injury, neurological level of injury, impairment scale of SCI and details of spine fracture or dislocation were all collected and analyzed. RESULTS: A total of 351 patients were included in the study, including 133 males (37.9%) and 218 females (62.1%). There were 231 cases (65.8%) without spine fracture or dislocation. SCI without fracture or dislocation (SCIWORA) was the most common in children between the age of 5 and 14 years (77.9%), and injuries caused by sports were the most common in girls (90.8%). Among sports injuries, those due to a special dance movement called "Xia-Yao" in Chinese, which involves hyperextension of the trunk, constituted the majority, with the neurological level of injuries located predominantly in the middle (34.6%) and lower (44.2%) thoracic levels. CONCLUSION: Girls between the ages of 5 and 14 years constituted the majority of SCIWORA injuries at the thoracic levels, which were caused mainly by "Xia-Yao". Overall, careful attention should be paid to prevent this kind of injury in children.

Phosphatidylserine released from apoptotic cells in tumor induces M2-like macrophage polarization through the PSR-STAT3-JMJD3 axis.

BACKGROUND: Understanding how the tumor microenvironment is shaped by various factors is important for the development of new therapeutic strategies. Tumor cells often undergo spontaneous apoptotic cell death in tumor microenvironment, these apoptotic cells are histologically co-localized with immunosuppressive macrophages. However, the mechanism by which tumor cell apoptosis modulates macrophage polarization is not fully understood. In this study, we aimed to explore the tumor promoting effects of apoptotic tumor cells and the signal pathways involved. METHODS: Apoptotic cells and macrophages in tumors were detected by immunohistochemical staining. Morphological analysis was performed with Giemsa staining. Lipids generated from apoptotic cells were detected by liquid chromatography-mass spectrometry. Phosphatidylserine-containing liposomes were prepared to mimic apoptotic cells. The expression of protein was determined by real-time PCR, immunohistochemistry enzyme-linked immunosorbent assay and Western blotting. Mouse malignant ascites and subcutaneous tumor models were designed for in vivo analysis. Transgenic mice with specific genes knocked out and inhibitors specific to certain proteins were used for the mechanistic studies. RESULTS: The location and the number of apoptotic cells were correlated with that of macrophages in several types of carcinomas. Phosphatidylserine, a lipid molecule generated in apoptotic cells, induced polarization and accumulation of M2-like macrophages in vivo and in vitro. Moreover, sustained administration of phosphoserine promoted tumor growth in the malignant ascites and subcutaneous tumor models. Further analyses suggested that phosphoserine induced a M2-like phenotype in macrophages, which was related to the activation of phosphoserine receptors including T-cell immunoglobin mucin 4 (TIM4) and the FAK-SRC-STAT3 signaling pathway as well as elevated the expression of the histone demethylase Jumonji domain-containing protein 3 (JMJD3). Administration of specific inhibitors of these pathways could reduce tumor progression. CONCLUSIONS: This study suggest that apoptotic cell-generated phosphoserine might be a notable signal for immunosuppressive macrophages in tumors, and the related pathways might be potential therapeutic targets for cancer therapy.

Homogeneously Mixing Different Metal-Organic Framework Structures in Single Nanocrystals through Forming Solid Solutions.

Pore engineering plays a significant role in the applications of porous materials, especially in the area of separation and catalysis. Here, we demonstrated a metal-organic framework (MOF) solid solution (MOSS) strategy to homogeneously and controllably mix NU-1000 and NU-901 structures inside single MOF nanocrystals. The key for the homogeneous mixing and forming of MOSS was the bidentate modulator, which was designed to have a slightly longer distance between two carboxylate groups than the original tetratopic ligand. All of the MOSS nanocrystals showed a uniform pore size distribution with a well-tuned ratio of mesopores to micropores. Because of the appropriate pore ratio, MOSS nanocrystals can balance the thermodynamic interactions and kinetic diffusion of the substrates, thus showing exceedingly higher separation abilities and a unique elution sequence. Our work proposes a rational strategy to design mixed-porous MOFs with controlled pore ratios and provides a new direction to design homogeneously mixed MOFs with a high separation ability and unique separation selectivity.

MIL-101-Cr/Fe/Fe-NH2 for Efficient Separation of CH4 and C3H8 from Simulated Natural Gas.

Adsorptive separation based on porous solid adsorbents has emerged as an excellent effective alternative to energy-intensive conventional separation methods in a low energy cost and high working capacity manner. However, there are few stable mesoporous metal-organic frameworks (MOFs) for efficient purification of methane from other light hydrocarbons in natural gas. Herein, we report a series of stable mesoporous MOFs, MIL-101-Cr/Fe/Fe-NH2, for efficient separation of CH4 and C3H8 from a ternary mixture CH4/C2H6/C3H8. Experimental results show that all three MOFs possess excellent thermal, acid/basic, and hydrothermal stability. Single-component adsorption suggested that they have high C3H8 adsorption capacity and commendable selectivity for C3H8 and C2H6 over CH4. Transient breakthrough experiments further certified the ability of direct separation of CH4 from simulated natural gas and indirect recovery of C3H8 from the packing column. Theoretical calculations illustrated that the van der Waals force proportional to the molecular weight is the key factor and that the structural integrity and defect can impact separation performances.