Extracting double-quantum coherence in two-dimensional electronic spectroscopy under pump-probe geometry

Two-dimensional electronic spectroscopy (2DES) can be implemented with different geometries, e.g., BOXCARS, collinear, and pump-probe geometries. The pump-probe geometry has the advantage of overlapping only two beams and reducing phase cycling steps. However, its applications are typically limited to observing the dynamics with single-quantum coherence and population, leaving the challenge to measure the dynamics of the double-quantum (2Q) coherence, which reflects the many-body interactions. We demonstrate an experimental technique in 2DES under pump-probe geometry with a designed pulse sequence and the signal processing method to extract 2Q coherence. In the designed pulse sequence, with the probe pulse arriving earlier than the pump pulses, our measured signal includes the 2Q signal as well as the zero-quantum signal. With phase cycling and data processing using causality enforcement, we extract the 2Q signal. The proposal is demonstrated with rubidium atoms. We observe the collective resonances of two-body dipole-dipole interactions in both the D1 and D2 lines.

Cross-phase modulation in two-dimensional spectroscopy

Developing from transient absorption (TA) spectroscopy, two-dimensional (2D) spectroscopy with pump-probe geometry has emerged as a versatile approach for alleviating the difficulty in implementing 2D spectroscopy with other geometries. However, the presence of cross-phase modulation (XPM) in TA spectroscopy introduces significant spectral distortions, particularly when the pump and probe pulses overlap. We demonstrate that this phenomenon is extended to the 2D spectroscopy with pump-probe geometry and the XPM is induced by the interference of the two pump pulses. We present the oscillatory behavior of XPM in the 2D spectrum and its displacement with respect to the waiting time delay through both experimental measurements and numerical simulations. Additionally, we explore the influence of probe pulse chirp on XPM and discover that by compressing the chirp, the impact of XPM on the desired signal can be reduced.

Design, qualification & manufacture of ITER gravity supports

As one of the key components to support all the magnet coils, the GS faces engineering challenge to its operational safety throughout the design, qualification and manufacturing process as a result of extreme loading condition. The structural safety of GS was confirmed by both the FEM analysis and the semi-prototype engineering test after a long time of design, qualification, manufacture and assembly. Welding the cooling pipe to the flexible plate without obvious deformation as well as tightening uniformly and precisely all the tie rods to clamp the plates were carried out successfully during manufacturing. The result of final vacuum leakage test indicates that the GS can not only meet the ITER vacuum requirement but also have no slow out-gassing. The first set of GS which has passed the ITER acceptance test is to be delivered to ITER construction site soon.

Adenovirus associated with acute diarrhea: a case-control study

Background

Diarrhea is a major source of morbidity and mortality among young children in low-income and middle-income countries. Human adenoviruses (HAdV), particular HAdV species F (40, 41) has been recognized as important causal pathogens, however limited data exist on molecular epidemiology of other HAdV associated with acute gastroenteritis.

Methods

In the present preliminary study, we performed a case-control study involving 273 children who presented diarrheal disease and 361 healthy children matched control in Children’s hospital of Hebei Province (China) to investigate the relationship between non-enteric HAdV and diarrhea. HAdV were detected and quantified using quantitative real-time PCR (qPCR) and serotyped by sequencing and phylogenetic analysis. Odds ratio (OR) was used to assess the risk factor of HAdV.

Results

HAdV were detected in 79 (28.94%) of 273 children with diarrhea including 7 different serotypes (HAdV 40, 41, 3, 2,1,5 and 57) with serotypes 40, 41 and 3 being the most dominant and in 26 (7.20%) of 361 healthy children containing 9 serotypes (HAdV 40, 41, 3, 2,1,5,57,6 and 31). A majority (91.14%) of HAdV positives occurred in diarrhea children and 65.38% in controls< 3 years of age. No significant difference in the viral load was found between case and control groups or between Ad41-positive patients and healthy controls. In addition to HAdV 40 and 41, HAdV 3 was also associated with diarrhea (OR = 17.301, adjusted OR = 9.205, p < 0.001).

Conclusions

Our results demonstrate a high diversity of HAdV present among diarrhea and healthy children and implicate that non-enteric HAdV3 may lead to diarrhea.

Development of a reverse transcription recombinase-aided amplification assay for the detection of coxsackievirus A10 and coxsackievirus A6 RNA

Hand, foot and mouth disease (HFMD) is a serious public health problem, and coxsackievirus A6 (CVA6) and coxsackievirus A10 (CVA10) are two of the major causative pathogens, in addition to enterovirus 71 (EV71) and coxsackievirus A16 (CVA16). A simple and rapid reverse transcription recombinase-aided amplification assay (RT-RAA) was developed for the detection of CVA10 and CVA6 in this study. The analytical sensitivity for detection of CVA10 and CVA6 at 95% probability by probit regression analysis was 35 copies per reaction and 38 copies per reaction, respectively, with 100% specificity. Compared with commercial RT-qPCR assays, when testing 455 fecal specimens, the kappa value of the RT-RAA assay for CVA10 and CVA6 was 0.920 (p < 0.001) and 0.952 (p < 0.001), respectively. Moreover, four samples that were positive for CVA10 and five that were positive for CVA6 by RT-RAA but negative by RT-qPCR were further determined to be true positives. These results demonstrate that the proposed RT-RAA assays are very valuable tools for the detection of CVA10 and CVA6 and have potential for use in resource-limited settings.

Use of a rapid reverse-transcription recombinase aided amplification assay for respiratory syncytial virus detection

In this study, a rapid reverse-transcription recombinase aided amplification (RT-RAA) assay was developed to detect respiratory syncytial virus (RSV) subgroups A and B, respectively. The reaction was performed at 39°C in less than 30min. The analytical sensitivities of RSVA and RSVB at 95% probability by probit regression analysis were 38copies per reaction and 35 copies per reaction, respectively, and no cross reactions with other related respiratory viruses were observed. The RT-RAA assay was further utilized to detect and subgroup 306 clinical specimens and the results showed that 79(25.82%, 79/306) samples were positive for RSV, of those 16(20.25%, 16/79) were identified as RSVA and 63(79.75%, 63/79) were RSVB, which is completely consistent with the results obtained by RSV RT-qPCR assay. In conclusion, the developed RAA assay will be of benefit as a faster, sensitive and specific alternative tool for detection of RSV.

[Clinical diagnosis and management of cervical spondylotic amyotrophy]

Objective: To investigate the clinical characteristics and surgical treatment of cervical spondylotic amyotrophy. Methods: Thirteen patients(13 man) with proximal (10) and distal(3) cervical spondylotic amyotrophy between November 2014 and September 2016 were included in this study. The average age of the patients was 55 (range, 47-66) years. The sex, age, clinical course, type of amyotrophy, lesion segment and postdecompression improvement in muscle power were reviewed. Results: Of 13 cervical spondylotic amyotrophy patients, 9 were performed on with cervical disectomy, 2 were performed on with cervical posterior operation, 2 remainding patients received nonoperative treatment. Cervical spondylotic amyotrophy patients were followed up 6-22 (average 10.6) months, muscle power of 4 patients (all proximal-type)were improved completely (the average recovery time were 4.4 months), muscle power of 6 patients were improved uncompletely, 1 patients failed to improve, the 2 remainding patients received nonoperative treatment had no change. Conclusion: Cervical spondylotic amyotrophy as a rare type of cervical spondylotic disorder, It should distinguish cervical spondylotic amyotrophy from amyotrophic lateral sclerosis, especially in the early stage of amyotrophic lateral sclerosis. A surgical treatment is recommended as the first line of proximal-type CSA, especially those with serious compression. It is important that clinicians should be aware that distal-type CSA had a poor results, resulting in a lower lower satisfaction, especially those with no, or insignificant, sensory disturbance.

Oblique cord (chorda obliqua) of the forearm and muscle-associated fibrous tissues at and around the elbow joint: a study of human foetal specimens

In adults, the oblique cord or chorda obliqua separates the origins of the flexor pollicis longus (FPL) and flexor digitorum profundus (FDP) muscles from the supinator muscle and elbow joint. This study examined the topographic anatomy of the oblique cord and related muscles in foetuses. Semiserial sections of five mid-term foetuses of gestational age (GA) 14-16 weeks and 12 late-stage foetuses of GA 28-30 weeks were histologically examined and three forearms at GA 30 weeks were macroscopically evaluated. Late-stage foetuses showed a fascial structure between the supinator and FDP muscles. The latter extended proximally to the elbow joint and the muscle origin thickened the distal, ulnar part of the capsule. The FPL origin also extended proximally but did not reach the joint capsule. These morphologies were consistent with macroscopic examinations. The brachialis muscle was widely inserted into the proximal, anterior part of the capsule. In addition, the medial collateral ligament was not covered by the pronator-flexor muscles but by the triceps brachii muscle. The oblique cord apparently did not form prenatally. After birth, the proximal parts of the FDP and FPL muscles were likely replaced by collagenous tissues, providing a specific type of intermuscular septum i.e., the oblique cord. This type of muscle-ligament transition was observed in the annular ligament of the radius. The foetal elbow joint was characterised by strong support by the FDP, brachialis and triceps brachii muscles. Therefore, the foetal elbow is not a miniature version of the adult elbow.

Metal induced self-assembly of designed V-shape protein into 2D wavy supramolecular nanostructure

In order to understand and imitate the more complex bio-processes and fascinating functions in nature, protein self-assembly has been studied and has attracted more and more interest in recent years. Artificial self-assemblies of proteins have been constructed through many strategies. However, the design of complicated protein self-assemblies utilizing the special profile of building blocks remains a challenge. We herein report linear and 2D nanostructures constructed from a V shape SMAC protein and induced by metal coordination. Zigzag nanowires and wavy 2D nanostructures have been demonstrated by AFM and TEM. The zigzag nanowires can translate to a 2D nanostructure with an excess of metal ions, which reveals the step by step assembly process. Fluorescence and UV/Vis spectra have also been obtained to further study the mechanism and process of self-assembly. Upon the protein nanostructure, fluorescence resonance energy transfer (FRET) could also be detected using fluorescein modified proteins as building blocks. This article provides an approach for designing and controlling self-assembled protein nanostructures with a distinctive topological morphology.

Phosphorylation of wheat germ initiation factors and ribosomal proteins

The ability of the wheat germ initiation factors and ribosomes to serve as substrates for a wheat germ protein kinase (Yan and Tao 1982 J Biol Chem 257: 7037-7043) has been investigated. The wheat germ kinase catalyzes the phosphorylation of the 42,000 dalton subunit of eukaryotic initiation factor (eIF)-2 and the 107,000 dalton subunit of eIF-3. Other initiation factors, eIF-4B and eIF-4A, and elongation factors, EF-1 and EF-2, are not phosphorylated by the kinase. Quantitative analysis indicates that the kinase catalyzes the incorporation of about 0.5 to 0.6 mole of phosphate per mole of the 42,000 dalton subunit of eIF-2 and about 6 moles of phosphate per mole of the 107,000 dalton subunit of eIF-3. Three proteins (M(r) = 38,000, 14,800, and 12,600) of the 60S ribosomal subunit are phosphorylated by the kinase, but none of the 40S ribosomal proteins are substrates of the kinase. No effects of phosphorylation on the activities of eIF-2, eIF-3, or 60S ribosomal subunits could be demonstrated in vitro.

Multiple forms of pyrophosphate:D-fructose-6-phosphate 1-phosphotransferase from wheat seedlings. Regulation by fructose 2,6-bisphosphate

Two forms of pyrophosphate:D-fructose-6-phosphate 1-phosphotransferase have been isolated from wheat seedlings. One of these enzymes, termed PFP-1, has been purified to homogeneity. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicates that the enzyme is composed of two different polypeptide chains of Mr = 67,000 (alpha) and 60,000 (beta). PFP-1 has been assigned a molecular structure consisting of alpha 2 beta 2 based on an estimated Mr of 234,000 for the native enzyme. PFP-2, the other form of phosphotransferase, has also been purified extensively. Preliminary data suggest that the active form of PFP-2 is probably a dimer of a polypeptide chain of Mr = 60,000. Immunological studies indicate that the two enzyme preparations share common antigenic determinants. The two forms of enzyme have very similar kinetic properties. The phosphotransferases are activated by fructose 2,6-bisphosphate (Fru-2,6-P2) which lowers the Km of the enzymes for fructose 6-phosphate but not that for PPi. Interestingly, PFP-1 is significantly more active than PFP-2 in the absence of Fru-2,6-P2. Also, PFP-1 exhibits a greater affinity (Ka = 7 nM) than PFP-2 (Ka = 26 nM) for the activator. Based on kinetic, immunological, and physicochemical parameters, it is suggested that the two enzymic forms are related in that they share the same catalytic moiety, i.e. the 60,000-dalton or beta subunit. The beta subunit when in complex formation with the alpha subunit, as in PFP-1, becomes more active in the absence of Fru-2,6-P2 as well as exhibits a greater sensitivity toward the effector.

Reversible phosphorylation of T-substrate by wheat germ, human erythrocyte, and rabbit skeletal muscle protein kinases

The reversibility of the reactions catalyzed by the wheat germ kinase and the cyclic AMP independent protein kinases isolated from human erythrocytes (casein kinases A and G) and rabbit skeletal muscle (casein kinases I and II) has been investigated. The reverse reaction requires ADP, Mg2+, phosphoprotein, and kinase and results in the formation of ATP from the phosphoprotein and ADP. The requirement for ADP in the wheat germ kinase and casein kinases II and G catalyzed reactions appears to be nonspecific. These kinases can also utilize GDP, IDP, and UDP as phosphoryl acceptors. Studies with the wheat germ protein T-substrate indicate that the phosphorylation of this protein substrate by the kinases is fully reversible. By contrast, the phosphorylation of phosvitin and casein is only partially reversible. Since the T-substrate is found to contain multiple phosphorylation sites and can serve as phosphoryl acceptor for the various kinases, the specificity of the phosphorylation of the substrate by the kinases is examined by way of the reverse reaction. The wheat germ kinase, casein kinase G, and casein kinase II appear to phosphorylate the same sites on the T-substrate as they are capable of completely dephosphorylating each other's 32P-T-substrate. Each of these kinases can catalyze the incorporation of 12 mol of 32P/48 000 g of T-substrate. In contrast, casein kinases A and I can incorporate only 6 mol of 32P/48 000 g of T-substrate. Studies on the reverse reactions suggest that these phosphorylation sites may be the same for both enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on an endogenous substrate of wheat germ protein kinase

An endogenous phosphoryl acceptor has been purified 138-fold from wheat germ extracts. This protein, termed T-substrate, is far more effective than casein or phosvitin as a phosphoryl acceptor for a wheat germ kinase recently purified by our laboratory. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicates that the T-substrate preparation is not homogeneous. The T-substrate, which migrates at a Mr = 48,000, constitutes about 90% of the total protein stain on the gel and is the only protein component which is phosphorylated by the wheat germ kinase. The hydrodynamic properties of the T-substrate have been determined by gel filtration and glycerol density gradient centrifugation. The protein exhibits a Stokes radius of 65.5 A, a sedimentation coefficient of 3.85 S, a frictional ratio of 2.11, and a molecular weight of approximately 104,000. The results suggest that the wheat germ T-substrate is a dimer. The protein exhibits a greater substrate specificity for the wheat germ kinase than for the cyclic AMP-dependent and several independent protein kinases isolated from rabbit skeletal muscle and human erythrocytes. The T-substrate can be maximally phosphorylated by the wheat germ kinase to the extent of about 8 mol of phosphate/48,000 g of protein. Complete dephosphorylation of the phospho-T-substrate occurred upon treatment with phosphatases. The phosphorylated amino acid was identified by high voltage electrophoresis of an acid hydrolysate of 32P-T-substrate. The results indicate that phosphorylation occurs mainly on the seryl residues of T-substrate.

Purification and characterization of a wheat germ protein kinase

A cyclic AMP-independent protein kinase has been purified from wheat germ extracts. The enzyme catalyzes the phosphorylation of casein and phosvitin but not protamine, histone, or bovine serum albumin. However, the best substrate for the kinase appears to be that of an endogenous wheat germ protein. The kinase can utilize both ATP and GTP as phosphoryl donors. A molecular weight of 36,000-38,000 had been estimated for the kinase by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by glycerol density gradient centrifugation and gel filtration in the presence of 0.5 M KCl. In the presence of low salt, however, the molecular weight of the kinase appears to double. In isoelectrofocusing, the kinase exhibits a pI of about 6.5. The activity of the kinase is strongly inhibited by spermine and heparin. Spermidine is slightly stimulatory at low concentrations but inhibitory at high concentrations. High concentrations of putrescine also inhibit the kinase activity, but not to the extent observed with the other polyamines. Both spermine and spermidine appear to enhance the kinase activity at low Mg2+ concentrations. The result suggests that these polyamines could partially replace Mg2+ for kinase activity.