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Anterior cruciate ligament (ACL) deficiency not only reduces knee stability, but also increases the risk of more disease and impairs daily life, thus requiring efficient detection of ACL deficiency. To build an efficient subject-independent ACL deficiency detection model, this study proposes a new method called SVM-MPA that fuses marine predator algorithm (MPA) and support vector machine (SVM) for simultaneous feature selection, hyperparameter optimization and classification. 35ACL-deficient (ACLD) and 35 ACL-intact (ACLI) participants were recruited to collect 6-degree-of-freedom knee kinematic data. Then, 216-dimensional multi-domain features covering time domain, frequency domain, time-frequency domain and nonlinearity were extracted. The error rate of SVM classification based on 5-fold cross-validation was used to construct the fitness of MPA, and MPA served to select features and optimize two hyperparameters for SVM. The majority voting strategy-based post-processing was introduced to convert the gait cycle-level to knee-level ACL deficiency detection. Comparing with 7 well-known meta-heuristic algorithms and running all 20 times, the best average gait cycle-level ACL deficiency detection performance (sensitivity: 96.78±0.4.84%, specificity: 99.43±5.70%, and accuracy: 98.48±1.70%) was obtained using the proposed method. With post-processing, this study improved the best (final) detection performance (sensitivity: 97.78±4.97%, specificity: 100±0.00%, and accuracy: 99.13±1.94%). These results demonstrate the feasibility and effectiveness of the proposed method and shows that an efficient subject-independent ACL deficiency detection model can be constructed using the proposed method, which makes it possible to provide a non-invasive, objective and accurate preoperative auxiliary detection method for diagnosing ACL deficiency clinically.

Background:Falling in older adults is one of the most common and serious problems leading to disability. Therefore, it is necessary to assess the risk of falls in older adults and take preventive measures in advance. The traditional risk assessment depends on the scale, which may be affected by the subjective factors of patients. However, in recent years, instruments have been developed to collect objective data related to gait in older adults.The aim of this study was to use objective gait data to predict fall risk in older adults. Methods:In this study, a total of 207 hospitalized older adults were recruited, and the Morse Fall Scale (MFS) and six-degrees-of-freedom (6-DOF) gait kinematic parameters of the lower limb joints were collected using a marker-based instrument. Based on the gait data, two important tasks in fall risk assessment were conducted, analysis of abnormal gait patterns and risk level classification. There were three fall risk levels corresponding to the scale, and an end-to-end attention-based convolution model was proposed to analyze gait kinematic data. Results: The model achieved an accuracy score of 0.878 and a recall score of 0.897 on the test set. In addition, we applied an attention-based heatmap to visualize the input data and features across the model. The color bars in the heatmap highly correlate with the level of fall risk and can serve as an indicator of the abnormal gait pattern. Conclusions: An end-to-end attention-based convolution model achieved a favorable result.Besides, the heatmap could serve as the indicator of risk level for each step and also provide further clues to the mechanism of falling. It has the potential to assist doctors in clinical work and contribute to further knowledge discovery.

Specific knee kinematic alterations have been theorized to correlate with the progression of cartilage degeneration, and therefore, post-traumatic osteoarthritis in patients with anterior cruciate ligament reconstruction (ACLR). However, how specific knee kinematic alterations contribute to knee joint cartilage degenerations remains to be unclear. To solve this problem, we hypothesized that there are specific cartilage-degenerating kinematic gait patterns that could be supported by the specific areas of cartilage lesions in ACLR knees. Thirty patients with unilateral ACLR knees and 30 healthy controls were recruited for the study. The kinematic differences between the ACLR knees and the healthy control knees during the stance phase were calculated to identify the kinematic patterns. Cartilage lesion distribution characteristics were acquired for patients with ACLR knees to validate the kinematic patterns using magnetic resonance images. Two kinematic patterns were modeled, i.e., sagittal (increased flexion angle and posterior tibial translation) and coronal (increased lateral tibial translation and abduction angle) kinematic patterns. For the sagittal pattern, the cartilage lesion distributions showed that there were more cartilage lesions (CLs) in the superoposterior regions than the posterior regions in the femoral condyles (p = 0.001), and more CLs in the posterior regions than the middle regions in the tibial plateau (p < 0.001). For the coronal pattern, the cartilage lesion distributions showed that there were more CLs in the lateral compartments near the tibial spine than the medial compartments near the tibial spine (tibial sides, p = 0.005 and femoral sides, p = 0.290). To conclude, the cartilage degeneration distribution evidence largely supports that the two kinematic patterns may contribute to cartilage degeneration in ACLR knees. These findings may provide a potential strategy of delaying early cartilage degeneration in ACLR knees by using motion (kinematic) pattern modification or training. However, investigations should be conducted on the actual effects of this potential strategy.

Tantalum (Ta) is used in orthopedic implants because it has excellent biocompatibility. However, high elastic modulus, bio-inertness, and unsatisfactory osteointegration limits its wider use in clinical applications. Herein, a 3D porous Ta scaffold with low elastic modulus was fabricated using selective laser melting (SLM). Strontium (Sr) was incorporated on the surface of the scaffold with the aid of polydopamine (PDA) to further improve its osteointegration ability. The prepared scaffolds exhibited a stable Sr ion release in 14 d. Rat bone marrow stem cells (BMSCs) showed improved early adhesion and spreading after Sr was incorporated on the porous Ta surface. The osteogenic behavior, including extracellular matrix mineralization (ECM), alkaline phosphatase activity (ALP), and expression of bone-related RNA, were all enhanced. Furthermore, the Sr-incorporated porous Ta scaffolds exhibited better angiogenic behavior, such as promoting migration, tube formation, and angiogenesis-related RNA expression abilities of human vascular endothelial cells (HUVECs). Additionally, histological images (H&E, Masson and CD31 immunofluorescent staining) suggested that Sr-incorporated porous Ta scaffolds displayed enhanced osteointegration and angiogenesis after implantation in rat femur for 12 weeks. These findings prove that the PDA-based Sr-incorporated porous Ta scaffolds show promising use in orthopedic implants.

Titanium (Ti) has been the most widely used orthopedic implant in the past decades. However, their inert surface often leads to insufficient osteointegration of Ti implant. To solve this issue, two bioactive Mg(OH)2 films were developed on Ti surfaces using hydrothermal treatment (Ti-M1# and Ti-M2#). The Mg(OH)2 films showed nano-flake structures: sheets on Ti-M1# with a thickness of 14.7 ± 0.7 nm and a length of 131.5 ± 2.9 nm, and on Ti-M2# with a thickness of 13.4 ± 2.2 nm and a length of 56.9 ± 5.6 nm. Both films worked as Mg ions releasing platforms. With the gradual degradation of Mg(OH)2 films, weakly alkaline microenvironments will be established surrounding the modified implants. Benefiting from the sustained release of Mg ions, nanostructures, and weakly alkaline microenvironments, the as-prepared nano-Mg(OH)2 coated Ti showed better in vitro and in vivo osteogenesis. Notably, Ti-M2# showed better osteogenesis than Ti-M1#, which can be ascribed to its smaller nanostructure. Moreover, whole genome expression analysis was applied to study the osteogenic mechanism of nano-Mg(OH)2 films. For both coated samples, most of the genes related to ECM-receptor interaction, focal adhesion, and TGF-β pathways were upregulated, indicating that these signaling pathways were activated, leading to better osteogenesis. Furthermore, cells cultured on Ti-M2# showed markedly upregulated BMP-4 gene expression, suggesting that the nanostructure with Mg ion release ability can better activate BMP-4 related signaling pathways, resulting in better osteogenesis. Nano-Mg(OH)2 films demonstrated a superior osteogenesis and are promising surface modification strategy for orthopedic applications., Graphical abstract Image 1, Highlights • Nano-Mg(OH)2 films were fabricated on Ti via hydrothermal treatment. • The as prepared films showed enhanced in vitro and in vivo osteogenesis. • Whole genome expression analysis was used to study the molecular mechanism.

Generalized joint hypermobility (GJH) is a highly prevalent disease that frequently affects the knee joint. The current literature has conflicting results about whether patients with GJH had knee kinematics deficiency during gait. This could be because most of the testing environment (level walking) was gentle and low-demanding for patients when studying their knee kinematics. With a high-demanding knee function and sagittal firm structure requirement, upslope walking was thought to stimulate sagittal knee kinematics deficiency in patients with GJH.However, only little investigation reported whether upslope walking could stimulate knee kinematic deficiency or not. We hypothesize that upslope walking can increase sagittal knee kinematic deficiency between GJH subjects and healthy controls.A three-dimensional motion analysis was conducted to explore whether upslope walking could stimulate sagittal knee kinematic deficiency in patients with GJH. A total of 44 patients with GJH and 44 healthy controls were recruited. Subjects walked on both level and upslope (15%) conditions when the kinematic data were collected. SPM1D analysis was taken to explore the differences between groups.Our results showed that upslope walking could significantly increase knee flexion angle and anterior tibial translation in both GJH patients and healthy controls (p 0.05). The increments of anterior tibial translation (values in upslope walking minus values in level walking) of GJH patients were greater than those of healthy controls (magnitude varying from 2.5 to 2.9 mm during 0-3% gait cycles (GC), p = 0.034; 1.4-2.9 mm during 93-100%GC, p = 0.012).The findings partially confirmed our hypothesis and suggested that upslope walking could increase anterior tibial translation deficiency in patients with GJH. Upslope walking may be a practical motion task in studying the weakness of knee kinematics of GJH subjects for researchers and scholars. Patients with GJH may face a more challenging knee kinematic environment than healthy controls in up-sloped activities.

Level Walking is a frequent functional movement during daily life. However, sloped walking is also common. Exploring 6DOF knee kinematics during sloped walking is important. It provides a reference for the rehabilitation, safety, and knee health of patients with knee diseases walking on sloped surfaces.The study aimed to explore 6DOF knee kinematics characteristics during sloped walking compared to level walking. We hypothesized that tibial anteroposterior translation and flexion angle (the sagittal plane) were significantly different from those of level walking.One hundred young, healthy adults (50 males and 50 females) were recruited for this study. A three-dimensional gait analysis system was used to collect 6DOF knee kinematics during level and sloped walking. The slope was set to ± 15% when the sloped walking was performed.Sloped walking mainly increased knee flexion angle (upslope, 2.5-26.2°, 1-100% gait cycle (GC), p 0.05; downslope, 1.7-11.9°, 15-95% GC, p 0.05) and anterior tibial translation (upslope, 0.7-4.1 mm, 3-54% GC0.6-2.1 mm, 80-94% GC; downslope, 1.0-2.2 mm, 21-69% GC) in the participants' knees. However, participants' other 4DOF knee kinematics during sloped walking were significantly different from those during level walking (p 0.05). Participants had 'drastically changeable' knee kinematic alterations in the transverse and coronal plane (the other 4DOF knee kinematics) during sloped walking compared to level walking.Our results confirmed the hypothesis. Sloped walking significantly increased anterior tibial translation (in most GC) and flexion angle. These kinematic changes in healthy subjects should be evaluated and further explored for patients with knee diseases, such as anterior cruciate ligament deficiency. Our findings are meaningful for their rehabilitation or safety or knee health while walking on sloped surfaces. Our study may provide a pilot reference for the 6DOF knee kinematic exploration of sloped walking.

Alternative polyadenylation (APA) enhances gene regulatory potential by increasing the diversity of mRNA transcripts. 3' UTR shortening through APA correlates with enhanced cellular proliferation and is a widespread phenomenon in tumor cells. Here, we show that the ubiquitously expressed transcription factor Sp1 binds RNA in vivo and is a common repressor of distal poly(A) site usage. RNA sequencing identified 2,344 genes (36% of the total mapped mRNA transcripts) with lengthened 3' UTRs upon Sp1 depletion. Sp1 preferentially binds the 3' UTRs of such lengthened transcripts and inhibits cleavage at distal sites by interacting with the subunits of the core cleavage and polyadenylation (CPA) machinery. The 3' UTR lengths of Sp1 target genes in breast cancer patient RNA-seq data correlate with Sp1 expression levels, implicating Sp1-mediated APA regulation in modulating tumorigenic properties. Taken together, our findings provide insights into the mechanism for dynamic APA regulation by unraveling a previously unknown function of the DNA-binding transcription factor Sp1.

The COVID-19 pandemic has caused over one million deaths thus far. There is an urgent need for the development of specific viral therapeutics and a vaccine. SARS-CoV-2 nucleocapsid (N) protein is highly expressed upon infection and is essential for viral replication, making it a promising target for both antiviral drug and vaccine development. Here, starting from a functional proteomics workflow, we initially catalogued the protein-protein interactions of 21 SARS-CoV-2 proteins in HEK293 cells, finding that the stress granule resident proteins G3BP1 and G3BP2 copurify with N with high specificity. We demonstrate that N protein expression in human cells sequesters G3BP1 and G3BP2 through its physical interaction with these proteins, attenuating stress granule (SG) formation. The ectopic expression of G3BP1 in N-expressing cells was sufficient to reverse this phenotype. Since N is an RNA-binding protein, we performed iCLIP-sequencing experiments in cells, with or without exposure to oxidative stress, to identify the host RNAs targeted by N. Our results indicate that SARS-CoV-2 N protein binds directly to thousands of mRNAs under both conditions. Like the G3BPs stress granule proteins, N was found to predominantly bind its target mRNAs in their 3’UTRs. RNA sequencing experiments indicated that expression of N results in wide-spread gene expression changes in both unstressed and oxidatively stressed cells. We suggest that N regulates host gene expression by both attenuating stress granules and binding directly to target mRNAs.

Generalized joint hypermobility (GJH) is a common, but often ignored, condition characterized by general joint laxity, which is reported to increase one's risk of anterior cruciate ligament (ACL) injury and osteoarthritis. Nevertheless, it is not clearly learned in the prevalence and dynamic characteristics in college students.Is the active motion stability in the six-degree-of-freedom (6DOF) kinematics of the knee joint of people with GJH poorer than that of others?This is a cross-sectional study. A population of 489 college students was recruited who was divided into two groups: a GJH group (Beighton score ≥ 4, n = 54) and a normal group (Beighton score4, n = 435). A paper questionnaire with questions about the participants' demographic characteristics and musculoskeletal disorder symptoms was collected. A three-dimensional gait analysis system was used to collect the participants' knee joint kinematic parameters during treadmill walking. Variables were evaluated using independent t-tests and Wilcoxon signed-rank tests.The prevalence of GJH was found to be 11.0 % among college students. Participants with GJH exhibited a greater active range of motions in the anterior/posterior translation than the normal (P = 0.026). Participants with GJH exhibited greater flexion at the end of the terminal stance (P = 0.039) and greater anterior translation of the tibia during almost the whole gait period than the normal group (P＜0.05) during the treadmill gait. A greater external angle was found in GJH group during the periods of middle stance (P = 0.008).GJH with a prevalence of 11.0 % among college students should be paid attention. Poor active motion stability in anterior/posterior translation may play an important role in the development of knee joint instability, potentially resulting in subsequent ACL deficiency and the development of knee osteoarthritis among people with GJH.

Recently, Zn and its alloys are hotspots in biodegradable implants for their desirable degradation rate. In this study, Ti coatings are deposited on Zn by magnetron sputtering to enhance its corrosion resistance and biocompatibility. The surface morphology and chemical compositions of the coatings are studied by SEM, XRD, and XPS. Though obvious Ti elements are detected on the surface of the coatings, the surface views do not change after deposited with Ti. Potentiodynamic polarization, Zn ion release, and corrosion morphology observations suggest that Ti coatings can improve the corrosion resistance of Zn. The cells cultured in the extracts of Ti-coated samples exhibit higher viability than those cultured in the extract of Zn. With enhanced corrosion resistance and cytocompatibility, Ti-coated Zn is believed to be a candidate coating for implant application.

The carboxy-terminal domain (CTD) of the RNA polymerase II (RNAPII) subunit POLR2A is a platform for modifications specifying the recruitment of factors that regulate transcription, mRNA processing, and chromatin remodelling. We previously found that symmetrical dimethylation (me2s) of a CTD Arginine residue (R1810 in human) causes recruitment of the Tudor domain of SMN, which interacts with Senataxin. SMN is mutated in spinal muscular atrophy (SMA), and Senataxin is sometimes mutated in Amyotrophic Lateral Sclerosis (ALS). R1810me2s and SMN, like Senataxin, are important for resolving R-loops (DNA:RNA hybrids) at transcription terminators. FUS and TDP-43 (TARDBP) are DNA/RNA binding proteins that are sometimes mutated in ALS and FTD (Frontotemporal dementia). Here we show that TDP-43 and, to some extent, FUS are recruited by the R1810me2s-SMN pathway. Defects in FUS and TDP-43 recruitment influence RNAPII termination and R-loop accumulation, leading to elevated DNA damage at terminators that may contribute to neurodegenerative disorders like ALS and FTD.

The carboxy-terminal domain (CTD) of the RNA polymerase II (RNAP II) subunit POLR2A is a platform for modifications specifying the recruitment of factors that regulate transcription, mRNA processing, and chromatin remodelling. Here we show that a CTD arginine residue (R1810 in human) that is conserved across vertebrates is symmetrically dimethylated (me2s). This R1810me2s modification requires protein arginine methyltransferase 5 (PRMT5) and recruits the Tudor domain of the survival of motor neuron (SMN, also known as GEMIN1) protein, which is mutated in spinal muscular atrophy. SMN interacts with senataxin, which is sometimes mutated in ataxia oculomotor apraxia type 2 and amyotrophic lateral sclerosis. Because POLR2A R1810me2s and SMN, like senataxin, are required for resolving RNA-DNA hybrids created by RNA polymerase II that form R-loops in transcription termination regions, we propose that R1810me2s, SMN, and senataxin are components of an R-loop resolution pathway. Defects in this pathway can influence transcription termination and may contribute to neurodegenerative disorders.

Antibodies are used in multiple cell biology applications, but there are no standardized methods to assess antibody quality-an absence that risks data integrity and reproducibility. We describe a mass spectrometry-based standard operating procedure for scoring immunoprecipitation antibody quality. We quantified the abundance of all the proteins in immunoprecipitates of 1,124 new recombinant antibodies for 152 chromatin-related human proteins by comparing normalized spectral abundance factors from the target antigen with those of all other proteins. We validated the performance of the standard operating procedure in blinded studies in five independent laboratories. Antibodies for which the target antigen or a member of its known protein complex was the most abundant protein were classified as 'IP gold standard'. This method generates quantitative outputs that can be stored and archived in public databases, and it represents a step toward a platform for community benchmarking of antibody quality.

SummaryChromatin regulation is driven by multicomponent protein complexes, which form functional modules. Deciphering the components of these modules and their interactions is central to understanding the molecular pathways these proteins are regulating, their functions, and their relation to both normal development and disease. We describe the use of affinity purifications of tagged human proteins coupled with mass spectrometry to generate a protein-protein interaction map encompassing known and predicted chromatin-related proteins. On the basis of 1,394 successful purifications of 293 proteins, we report a high-confidence (85% precision) network involving 11,464 protein-protein interactions among 1,738 different human proteins, grouped into 164 often overlapping protein complexes with a particular focus on the family of JmjC-containing lysine demethylases, their partners, and their roles in chromatin remodeling. We show that RCCD1 is a partner of histone H3K36 demethylase KDM8 and demonstrate that both are important for cell-cycle-regulated transcriptional repression in centromeric regions and accurate mitotic division.

SUMMARY The RNA polymerase II (RNAPII) carboxyl-terminal domain (CTD) heptapeptide repeats (Y1-S2-P3-T4-S5-P6-S7) undergo dynamic phosphorylation and dephosphorylation during the transcription cycle to recruit factors that regulate transcription, RNA processing and chromatin modification. We show here that RPRD1A and RPRD1B form homodimers and heterodimers through their coiled-coil domains and interact preferentially via CTD interaction domains (CIDs) with CTD repeats phosphorylated at S2 and S7. Our high resolution crystal structures of the RPRD1A, RPRD1B and RPRD2 CIDs, alone and in complex with CTD phosphoisoforms, elucidate the molecular basis of CTD recognition. In an interesting example of cross-talk between different CTD modifications, our data also indicate that RPRD1A and RPRD1B associate directly with RPAP2 phosphatase and, by interacting with CTD repeats where phospho-S2 and/or phospho-S7 bracket a phospho-S5 residue, serve as CTD scaffolds to coordinate the dephosphorylation of phospho-S5 by RPAP2.

C2H2 zinc finger proteins represent the largest and most enigmatic class of human transcription factors. Their C2H2-ZF arrays are highly variable, indicating that most will have unique DNA binding motifs. However, most of the binding motifs have not been directly determined. In addition, little is known about whether or how these proteins regulate transcription. Most of the ∼700 human C2H2-ZF proteins also contain at least one KRAB, SCAN, BTB, or SET domain, suggesting that they may have common interacting partners and/or effector functions. Here, we report a multifaceted functional analysis of 131 human C2H2-ZF proteins, encompassing DNA binding sites, interacting proteins, and transcriptional response to genetic perturbation. We confirm the expected diversity in DNA binding motifs and genomic binding sites, and provide motif models for 78 previously uncharacterized C2H2-ZF proteins, most of which are unique. Surprisingly, the diversity in protein–protein interactions is nearly as high as diversity in DNA binding motifs: Most C2H2-ZF proteins interact with a unique spectrum of co-activators and co-repressors. Thus, multiparameter diversification likely underlies the evolutionary success of this large class of human proteins.

A series of heterometallic LnIII–SbIII edta-containing compounds with the formulas [Sb2(edta)2Ln]NO3·nH2O [edta = ethylenediaminetetraacetate; Ln = Eu, n = 7 (1); Gd, n = 7.5 (2) and Tb, n = 8 (3)] were synthesized and characterized by elemental analyses (EA), powder X-ray diffraction (PXDP), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analyses (TGA). Their fluorescence and magnetic properties were also studied. The thermal analysis demonstrates the compounds formation of the antimony, lanthanide ions, and edta4– ligands. FT-IR spectra reveal that the antimony and lanthanide ions are connected through the carboxylate bridges. The studies of luminescence properties show that compounds 1 and 3 exhibit typical luminescence in the visible region. Furthermore, magnetic properties reveal compounds 2 and 3 have weak ferromagnetic behavior.

A new heterometallic antimony–samarium complex, [Sb2(edta)2Sm(H2O)4]NO3 · 3.55H2O (edta = ethylenediaminetetraacetate) (1), has been synthesized and characterized by elemental analyses (EA), Fourier transform infrared spectroscopy, thermogravimetry-differential scanning calorimetry, and X-ray crystallography. The X-ray crystal structure analysis reveals that in 1 the bridging carboxylate-O,O′ of edta4− connects samarium(III) and antimony(III) to form 2-D sheets. The 2-D sheets are further linked by bridging carboxylates from adjacent layers, resulting in 3-D coordination polymers. Complex 1 exhibits fluorescence in the solid state at room temperature.

A new ethylenediamine-N,N,N′,N′-tetraacetate (edta)-linked heterometallic holmium–antimony compound 1 with the formula [Sb2(edta)2Ho(H2O)4]NO3·3.6H2O has been synthesized and characterized by elemental analyses (EA), X-ray crystallography, X-ray powder diffraction patterns (PXRDs), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analyses (TGA). X-ray crystal structure analysis reveals that the bridging carboxylate-O, O′ groups of edta, connect with Ho(III) and Sb(III) ions to form a 2D heterometallic network in compound 1. The 2D networks are further linked by bridging the carboxylate groups from the adjacent layers, resulting in the 3D coordination polymer. The thermal stability and the thermal decomposition process of this crystalline material have also been investigated by TGA–DSC. In addition, the magnetic properties of compound 1 have been studied.

The novel three-dimension edta-linked (edta=ethylenediamine-N,N,N′,N′-tetraacetate) heterometallic complex [Sb2(edta)2-µ4-Co(H2O)2]·5.15H2O has been synthesized and characterized by elemental analyses, FT-IR spectrum, X-ray diffraction analyses and thermogravimetry-differential scanning calorimetry (TG-DSC). The complex crystallizes in the monoclinic system, space group P21/n, lattice parameters: a=0.69969(2) nm, b=2.08705(4) nm, c=1.08106(2) nm, β=90.031(1)°, V=1.57866(6) nm3, Z=2, Mr=1007.76, Dc=2.120 g·cm−3, F(000)=1001, µ=2.323 mm−1, the final R=0.0235 and wR=0.0629 for 3480 observed reflections [I>2δ(I)]. In the structure each Co(II) ion is connected with Sb(III) ions bridging by four carboxylic oxygen atoms, and in each [Sb(edta)]− anion, the Sb(III) ion is six coordinated by two nitrogen and four oxygen from edta ions, together with a lone electron pair at the equatorial position. In the complex, the coordination number of Co(II) ion is six and its coordination environment is composed of four carboxylic oxygen atoms from four different edta ions and two oxygen atoms from two H2O molecules. The degradation of the sample proceeds in several steps and the water molecules and ligands are successively emited.

Samnium(III)-bismuth(III) heterobimetallic complexes, SmBi(edta)(NO3)2·7H2O (1) and SmBi(dtpa)(NO3)·3.5H2O(2) (edta=ethylenediaminetetraacetate, dtpa=diethylenetriaminepentaacetate), were synthesized and characterized by means of X-ray single crystal diffraction, X-ray powder diffraction, elemental analysis, ICP, FT-IR spectra and thermal analysis. The structure analysis revealed that 1 is in crystalline and 2 is in non-crystal state. Complex 1 crystallizes in monoclinic, space group P2(1)/n with a=1.2622(2) nm, b=0.81157(15) nm, c=2.3634(5) nm, β=105.340(2)°, V=2.3347(8) nm3, Z=4, Dc=2.563 g·cm−3, µ=10.125 mm−1. Bridging edta4− anions between Bi(III) atoms and Sm(III) atoms result into infinite 3D network structure. Thermal decomposition of the two complexes proceeds in similar stages, i.e., dehydration, pyrolysis of ligand, and decomposition of salt, and the final residue is oxide. In addition, the spectral properties have been studied through FL spectra and UV-Vis DRS. The two complexes exhibit one broad band Bi 6s6p-6s2 emission under UV excitation and the characteristic Sm3+ ion 4G5/26HJ/2 (J=5, 7, 9, 11) transitions under visible light excitation, respectively.

Protein complexes and protein-protein interactions are essential for almost all cellular processes. Here, we establish a mammalian affinity purification and lentiviral expression (MAPLE) system for characterizing the subunit compositions of protein complexes. The system is flexible (i.e. multiple N- and C-terminal tags and multiple promoters), is compatible with GatewayTM cloning, and incorporates a reference peptide. Its major advantage is that it permits efficient and stable delivery of affinity-tagged open reading frames into most mammalian cell types. We benchmarked MAPLE with a number of human protein complexes involved in transcription, including the RNA polymerase II-associated factor, negative elongation factor, positive transcription elongation factor b, SWI/SNF, and mixed lineage leukemia complexes. In addition, MAPLE was used to identify an interaction between the reprogramming factor Klf4 and the Swi/Snf chromatin remodeling complex in mouse embryonic stem cells. We show that the SWI/SNF catalytic subunit Smarca2/Brm is up-regulated during the process of induced pluripotency and demonstrate a role for the catalytic subunits of the SWI/SNF complex during somatic cell reprogramming. Our data suggest that the transcription factor Klf4 facilitates chromatin remodeling during reprogramming.

Messenger RNA 3′-end formation is functionally coupled to transcription by RNA polymerase II. By tagging and purifying Ref2, a non-essential protein previously implicated in mRNA cleavage and termination, we isolated a multiprotein complex, holo-CPF, containing the yeast cleavage and polyadenylation factor (CPF) and six additional polypeptides. The latter can form a distinct complex, APT, in which Pti1, Swd2, a type I protein phosphatase (Glc7), Ssu72 (a TFIIB and RNA polymerase II-associated factor), Ref2, and Syc1 are associated with the Pta1 subunit of CPF. Systematic tagging and purification of holo-CPF subunits revealed that yeast extracts contain similar amounts of CPF and holo-CPF. By purifying holo-CPF from strains lacking Ref2 or containing truncated subunits, subcomplexes were isolated that revealed additional aspects of the architecture of APT and holo-CPF. Chromatin immunoprecipitation was used to localize Ref2, Ssu72, Pta1, and other APT subunits on small nucleolar RNA (snoRNA) genes and primarily near the polyadenylation signals of the constitutively expressed PYK1 and PMA1 genes. Use of mutant components of APT revealed that Ssu72 is important for preventing readthrough-dependent expression of downstream genes for both snoRNAs and polyadenylated transcripts. Ref2 and Pta1 similarly affect at least one snoRNA transcript.