The catalysis performances of the composite molecular sieves were investigated in the aromatization reaction of n-pentane. The results indicated that the desired core-shell composite molecular sieves were obtained when the crystallization conditions were 36 hours, 100 °C and secondary crystallization. The aromatization results showed that core-shell composite molecular sieves had better selectivity for producing high application value xylenes compared to mixed-crystal composite molecular sieves.Using Y molecular sieve as the core, Y/SBA-15 composite molecular sieves were prepared by different crystallization methods in the paper. The growth process and morphologies of the composite molecular sieves were controlled by adjusting the synthesis factors. The structures and acidity of two kinds of composite molecular sieves were characterized by X-ray diffraction (XRD), N Microporous molecular sieves have relatively strong acidity12et al.Composite molecular sieves are increasingly popular, as they help combine the advantages of different types of molecular sieves while limiting their drawbacks. Among the different composite molecular sieves with hierarchical porous structures, composite molecular sieves with core-shell structure have shown outstanding catalytic performance56et al.The demand for light aromatics BTX  as important organic chemical raw materials and free blending components has increased progressively15n-pentane aromatization reaction by monitoring the product yields.In this study, we synthesized a composite molecular sieve with SBA-15 as shell and Y as core by using a hydrothermal method. The effects of the main crystallization conditions, including time and temperature, on the open-framework structure and acidity of the resulting composite molecular sieves were investigated. The catalytic performances of the prepared molecular sieves were evaluated in the Sodium aluminate, sodium hydroxide, sodium silicate, cerium nitrate, heptanes, toluene and tetraethyl orthosilicate (TEOS) were all analytical pure reagents and purchased from Sinopharm Group Co. LTD. Triblock copolymer poly (ethylene glycol)-block-poly (propylene glycol)-block-poly (ethylene glycol) (Pluronic P123) was purchased from Sigma Aldrich, America. Y type microporous materials is provided by Fushun Petrochemical Research Institute.2O, TEOS, and HY were added in the weight ratio m(P123):m(H2O):m(TEOS):m(HY) of 4:30:9.5:4. Then, hydrochloric acid of a certain concentration was slowly added into the mixture to adjust the pH to 2–3. The mixture was agitated for a certain amount of time and then placed into the hydrothermal reactor. The solutions were crystallized in the oven at 100 °C for 10, 24, 36, and 48 hours.To a three-necked flask, triblock copolymer P123, HThe mother liquor (30 ml) was placed in the oven at 100 °C keeping 36 hours for crystallization. After completion of the reaction, the product was filtered, dried and incinerated to give the single crystallized Y/SBA-15 micro-/meso-porous composite molecular sieve, labeled as YS-S.The mother liquor (30 ml) was placed in the 60 °C oven for 10 hours and followed another 26 hours in the 100 °C oven for crystallization. When the reaction was completed, the product was dried and incinerated to give the Y/SBA-15 micro-/meso-porous composite molecular sieve of secondary crystallization, labeled as YS-D.2 adsorption-desorption isotherms were measured at −196 °C with a Auto Chemisty 2010 instrument. Transmission electron microscopy (TEM) micrographs were collected on a Philips CM200 microscope. NH3-TPD patterns were recorded on a RC-IR-TP-3030  to detect surface acidity of the molecular sieves. TPD of NH3 experiments were performed using 100 mg samples. After pretreatment in He environment at 400 °C for 1 h, samples were cooled to room temperature and then saturated with anhydrous NH3 (4% in He) at a flow rate of 30 ml/min for about 30 min. Desorption was carried out by heating the samples in He environment (40 ml/min) from 100 °C to 800 °C with a heating rate of 5 °C/min.XRD patterns of the catalysts were obtained with a XRD-700 X-ray diffractometer in the 2 theta ranges of 0.5–70° (Rigaku Co.) by using Cu Ka radiation combined with a Ni filter. The NA MRT-6103 10 ml fixed bed micro-reactor, equipped with a stainless steel tube of 10 mm inner diameter was used. The calculation method of catalyst weight is as follows:−1. The product analysis was conducted on a SP-2000 gas chromatography (GC) instrument using 3 m of 8% organobentonite packed column. The temperature programming method was used. The column temperature was first held at 30 °C for 0.5 minutes, then raised to 80 °C at the rate of 2.5 °C/min, and held at 80 °C for 0.5 minutes. Afterwards, the temperature was raised to 160 °C at the rate of 5 °C/min and held at this temperature for 20 minutes. The inlet temperature was set to be 250 °C and the FID detector temperature was set to be 280 °C. The head pressure was 1000 KPa; the split ratio was 50:1; and the sample injection volume was 1 μL.So the reactor was operated under atmospheric pressure with 5 g of catalyst YS-S and YS-D, respectively. The reaction conditions were as follows. The temperature was set to be 530 °C, the pressure was set to be 0.1 MPa, and the weight hourly space velocity (WHSV) was set to be 1 hThe crystallization temperature is known to have significant impact on the structure of the mesoporous molecular sieve SBA-15It can be seen from The XRD spectra of samples YS-S and YS-D are shown in The TEM images of YS-S and YS-D are shown in Overall, the composite molecular sieves prepared by secondary crystallization had better morphology and crystal growth. This is due to the fact that the initial low temperature crystallization stage induced the process of nucleation, which prevented the disordered and irregular mesoporous channels formed by the splicing growth of the crystals due to the one-step high temperature crystallization. Secondary crystallization induced the ordered formation of mesoporous channels and had oriented synthesis effect on core-shell composite molecular sieves.2 adsorption-desorption isotherm of the composite molecular sieves prepared by single and secondary crystallization methods.2 adsorption-desorption isotherms of the Y/SBA-15 composite molecular sieves prepared by the two methods showed obvious microporous and mesoporous characteristics, which demonstrated that they were composite molecular sieves with composite pore structures. The saturated adsorption capacity of Y/S-D was around 175 cm3/g, while that of Y/S-S was around 140 cm3/g. Due to the irregular growth, there was a certain amount of defect in the open-framework structure of the molecular sieves prepared by single crystallization, resulting in lower specific surface area and pore volume .


The electrospun nanofibers transformed into hollow nanosphere FeSe2@GC–rGO hybrid nanofibers through a Fe@GC–rGO intermediate. The discharge capacities of the bare FeSe2 nanofibers, nanorod FeSe2–rGO–amorphous carbon (AC) hybrid nanofibers, and hollow nanosphere FeSe2@GC–rGO hyrbid nanofibers at a current density of 1 A g−1 for the 150th cycle were 63, 302, and 412 mA h g−1, respectively, and their corresponding capacity retentions measured from the 2nd cycle were 11, 73, and 82%, respectively. The hollow nanosphere FeSe2@GC–rGO hybrid nanofibers delivered a high discharge capacity of 352 mA h g−1 even at an extremely high current density of 10 A g−1. The enhanced electrochemical properties of the hollow nanosphere FeSe2@GC–rGO composite nanofibers arose from the synergetic effects of the FeSe2 hollow morphology and highly conductive rGO matrix.A novel one-dimensional nanohybrid comprised of conductive graphitic carbon (GC)-coated hollow FeSe To surmount this, construction of a stable artificial coating layer on the surface of the hollow structure would be another effective strategy for further maintaining the structural integrity via accommodating the huge volume variations induced by Na+ diffusion272829To overcome these issues, developing efficient anode materials for application in SIBs with good electrochemical performance is urgently needed and desirable. Thus far, one-dimensional (1D) nanomaterials have been recognized as the most desirable materials for applications in energy storage1415162@GC–rGO). Novel-structured rGO nanofibers comprising graphitic carbon-coated FeSe2 hollow nanospheres selected as the first target material were prepared by applying the nanoscale Kirkendall diffusion process to the conventional electrospinning process in order to create this anode material for SIBs, although there has been scarce study concerning the electrochemical-reaction mechanism of FeSe2 for SIBs. The electrochemical properties of the FeSe2@GC–rGO hybrid nanofibers comprising FeSe2 hollow nanospheres were compared with those of the bare FeSe2 nanofibers and FeSe2–rGO–amorphous carbon (AC) hybrid nanofibers comprising FeSe2 nanorods.Herein, we designed 1D nanomaterials comprising graphitic carbon (GC)-coated hollow metal chalcogenide nanospheres decorated within a reduced graphene oxide (rGO) nanofiber  than Fe cations ] through intermediate yolk–shell-structured nanopowders with the configuration Fe@void@FeSe2   -③. In th3 with a mean diameter of 3 μm had filled structures and smooth surfaces. The morphologies of the metallic Fe@GC–rGO hybrid nanofibers obtained after the reduction process are shown in 2O3. The exposure of ultrafine Fe nanocrystals under an air atmosphere at room temperature after the reduction process formed the Fe2O3 layer via surface oxidation. The diffusion out of the Fe component into the surface of the nanopowders via nanoscale Kirkendall diffusion formed the nanopowders with the yolk–shell structures. The nanopowder shown in the high-resolution TEM image in 2O3@GC (graphitic carbon). The graphitic carbon formed due to the Fe catalyst uniformly covering the Fe@Fe2O3 nanopowder. The high-resolution TEM image shown in 2O3, and graphitic carbon phase, respectively. The SAED and XRD patterns shown in 2O3 phase due to the partial surface oxidation of Fe nanocrystals by exposure in air. The elemental-mapping images shown in The morphologies of the electrospun nanofibers are shown in 2@GC–rGO hybrid nanofibers formed via the selenization process of the metallic Fe@GC–rGO hybrid nanofibers are shown in 2 and graphitic carbon, respectively. The SAED and XRD patterns shown in 2@GC–rGO hybrid nanofibers. The Fe-to-Se component ratio observed from the energy dispersive spectroscopy (EDS) analysis shown in D and G bands of carbon around 1340 and 1590 cm−1, respectively. The higher signal peak intensity of the D band compared to that of the G band is indicative of the thermal reduction of GO nanosheets to rGO nanosheets during the post-heat-treatment process2 hollow nanospheres over the hybrid nanofibers.The morphologies of the hollow nanosphere FeSe2@GC–rGO hybrid nanofibers were characterized via X-ray photoelectron spectroscopy (XPS). In the Fe 2p spectrum of the metallic Fe@GC–rGO hybrid nanofibers shown in p3/2 and 724 eV for Fe 2p1/2, which are the characteristic peaks of Fe(III) in a-Fe2O3 due to the partial surface oxidation of the Fe nanocrystals by exposure in airp spectrum of the hollow nanosphere FeSe2@GC–rGO hybrid nanofibers shown in p3/2 and 720 eV for Fe 2p1/2; these are characteristic of FeSe2 and a shake-up satellited spectrum in d5/2 and 55.31 eV for Se 3d3/2 were also confirmed to be in good agreement with the reported values for FeSe2 in the literature2 impurities formed during the selenization process. The C 1s peak shown in sp2-bonded carbon (C–C), epoxy and alkoxy groups (C–O), and carbonyl and carboxylic (C=O) components at 284.6, 286.6, and 288.1 eV, respectively2@GC–rGO hybrid nanofibers shown in 2 with oxygen resulted in a weight increase around 230 °C. The two-step weight loss observed at temperatures between 250 and 500 °C was attributed to the decomposition of FeSe2 into Fe2O3 and the combustion of rGO and GC. The rGO–GC content of 27% was estimated from the TG analysis of the hollow nanosphere FeSe2@GC–rGO hybrid nanofibers.The chemical state and molecular environment of the metallic Fe@GC–rGO and hollow nanosphere FeSe2 and nanorod FeSe2–rGO–AC hybrid nanofibers as the comparison samples were also prepared via a selenization process of the bare Fe2O3 and FeOx–rGO–AC hybrid nanofibers, respectively. The bare Fe2O3 nanofibers shown in 2O3 nanofibers with cubic structure transformed into bare FeSe2 nanofibers with orthorhombic structure via the selenization process shown in 2O3 nanocrystals transformed into the submicron-sized FeSe2 crystals during the selenization process. The high-resolution TEM image shown in 2 phase. The SAED and XRD patterns shown in 2 nanofibers. In addition, the elemental-mapping images shown in 2 nanofibers.Bare FeSe2–rGO–AC hybrid nanofibers prepared via the selenization of the FeOx–rGO–AC hybrid nanofibers also had a unique structure. The FeSe2 nanorods were uniformly embedded within the rGO–AC nanofibers, as shown by the SEM and TEM images in 2 nanorods measured from the TEM images was 148 nm. The high-resolution TEM image shown in 2 phase. The SAED and XRD patterns shown in 2–rGO–AC hybrid nanofibers with a pure crystal structure of the FeSe2 phase. The elemental-mapping images shown in 2 nanocrystals within the rGO–AC hybrid matrix. The N2-adsorption and -desorption isotherms and BJH pore size distributions of the three samples are shown in 2, nanorod FeSe2-rGO-AC, and hollow nanosphere FeSe2@GC–rGO hybrid nanofibers were 4, 9, and 34 m2 g−1, respectively. The nanorod FeSe2–rGO–AC and hollow nanosphere FeSe2@GC–rGO hybrid nanofibers showed well-developed mesopores due to their carbon materials.The nanorod FeSe2@GC–rGO hybrid nanofibers for sodium ion storage were compared with those of the bare FeSe2 and nanorod FeSe2–rGO–AC hybrid nanofibers via cyclic voltammograms (CVs) and galvanostatic discharge–charge cycling in a voltage range of 0.001–3.0 V vs Na/Na+. The CVs of the hollow nanosphere FeSe2@GC–rGO hybrid nanofibers during the first five cycles at a scan rate of 0.07 mV s−1 are shown in 2@GC–rGO hybrid nanofibers showed three distinct peaks located at 1.1, 0.7, and 0.4 V. The sharp reduction peak located at 1.1 V was attributed to the formation of NaxFeSe22Se, first, and Fe and Na2Se, second, respectivelyxFeSe2 and FeSe2, and the subsequent decomposition of the SEI layer, respectively3334352 nanocrystals during the first discharge and charge processes resulted in the reduction peak shift to a high potential. The CV curves of the bare FeSe2 and nanorod FeSe2–rGO–AC hybrid nanofibers shown in 2@GC–rGO hybrid nanofibers. The initial discharge and charge curves of the three samples at a current density of 1 A g−1 are shown in 2, nanorod FeSe2-rGO-AC, and hollow nanosphere FeSe2@GC–rGO hybrid nanofibers were 667, 589, and 642 mA h g−1, respectively, and their corresponding initial charge capacities were 578, 401, and 452 mA h g−1, respectively. The nanorod FeSe2–rGO–AC and hollow nanosphere FeSe2@GC–rGO hybrid nanofibers had lower initial Coulombic efficiencies than that of the bare FeSe2 nanofibers due to the high initial irreversible-capacity loss of the carbon material. The cycling performances of the three samples at a current density of 1 A g−1 are shown in 2–rGO–AC and hollow nanosphere FeSe2@GC–rGO hybrid nanofibers had superior cycling performances compared to that of the bare FeSe2 nanofibers. The discharge capacities of the bare FeSe2, nanorod FeSe2–rGO–AC, and hollow nanosphere FeSe2@GC–rGO hybrid nanofibers for the 150th cycle were 63, 302, and 412 mA h g−1, and their corresponding capacity retentions measured from the 2nd cycle were 11, 73, and 82%, respectively. The initial discharge and charge curves of the nanorod FeSe2-rGO-AC and hollow nanosphere FeSe2@GC–rGO hybrid nanofibers at a low current density of 0.05 A g−1 are shown in 2@GC–rGO hybrid nanofibers with their unique structure resulted in higher capacities than those of the nanorod FeSe2–rGO–AC hybrid nanofibers at a high current density of 1 A g−1. The rate performances of the three samples are shown in −1. The hollow nanosphere FeSe2@GC–rGO hybrid nanofibers showed superior rate performance compared to those of the bare FeSe2 and nanorod FeSe2–rGO–AC hybrid nanofibers. The gap between the discharge capacities of the nanorod FeSe2–rGO–AC and hollow nanosphere FeSe2@GC–rGO hybrid nanofibers showing good cycling performances for sodium ion storage increased with increasing current densities. The hollow nanosphere FeSe2@GC–rGO hybrid nanofibers had final discharge capacities of 510, 494, 466, 448, 443, 425, 404 and 352 mA h g−1 at current densities of 0.3, 0.5, 1.0, 2.0, 3.0, 5.0, 7.0, and 10 A g−1, respectively. The discharge capacities of the hollow nanosphere FeSe2@GC–rGO hybrid nanofibers were well recovered to 605 mA hg−1 when the current density was returned to 0.3 A g−1 after cycling at high current densities. The formation of a polymeric gel-like film on the active material resulted in the high capacities of the hollow nanosphere FeSe2@GC–rGO hybrid when the current density was returned to 0.3 A g−1 after cycling at high current densities.The electrochemical properties of the hollow nanosphere FeSe2@GC–rGO hybrid nanofibers compared to those of bare FeSe2 and nanorod FeSe2–rGO–AC hybrid nanofibers. The Nyquist plots shown in 2–rGO–AC hybrid nanofibers with high conductivity originated by AC, and lower surface area compared to hollow nanosphere FeSe2@GC–rGO had lower Rct than those of the other two nanofibers before cycling, as shown in Rct values of the three samples decreased abruptly after the first cycle due to the transformation of the FeSe2 crystals into ultrafine nanocrystals during the first cycle3738Rct values of the bare FeSe2 nanofibers increased strictly during cycling, as shown in Rct values of the hollow nanosphere FeSe2@GC–rGO and nanorod FeSe2–rGO–AC hybrid nanofibers remained constant during 70 cycles, as shown in Rct values of the bare FeSe2, nanorod FeSe2–rGO–AC, and hollow nanosphere FeSe2@GC–rGO hybrid nanofibers after 70 cycles were 79, 41, and 41 Ω, respectively. The results of the EIS measurements revealed the structural stability of the hollow nanosphere FeSe2@GC–rGO and nanorod FeSe2–rGO–AC hybrid nanofibers during the repeated Na insertion and extraction processes. In contrast, the structural destruction during cycling increased the Rct values of the bare FeSe2 nanofibers. Therefore, the structural stability and fast sodium insertion and desertion characteristics of the hollow nanosphere FeSe2@GC–rGO hybrid nanofibers correlated to their excellent Na ion storage properties.Electrochemical-impedance-spectroscopy (EIS) measurements of the three samples were taken before and after 1, 20, 50, and 70 cycles to investigate the superior sodium ion storage properties of the hollow nanosphere FeSe2@GC–rGO hybrid, nanorod FeSe2-rGO-AC hybrid, and bare FeSe2 nanofibers obtained after the 100th cycle, are shown in 2@GC–rGO hybrid nanofibers maintained their original morphologies well even after long-term cycling as shown by TEM images in 2 nanospheres was well observed. The nanorod FeSe2-rGO-AC hybrid nanofibers had also maintained overall morphologies after cycling, as shown in 2 nanofibers completely destroyed after cycling, as shown in The morphologies of the hollow nanosphere FeSe2@GC–rGO hybrid nanofibers arose from the synergetic effects of the highly conductive rGO nano-network matrix composing the fiber and the FeSe2 hollow sphere encapsulated within GC coating layer. First of all, rGO nano-network matrix surrounding the FeSe2@GC spheres acted as efficient conductive channels for electrons to transfer easily, as shown in 2@GC spheres during repeated cycling by enwrapping the spheres. In addition to the role of rGO nano-network matrix, FeSe2 hollow sphere with GC coating layer played at least three significant roles for further improvement in the electrochemical properties. First, FeSe2 hollow sphere lowered Na+ diffusion-induced stresses, consequently alleviating the volume variations upon Na+ insertion and desertion, and also had short diffusion length for Na+, increased contact area between the electrolyte and electrode in comparison with solid structures. Second, the highly conductive GC coating layer on the FeSe2 hollow sphere could primarily serve as fast and continuous transport pathways for electrons before electrons are transferred to secondary pathway of rGO nano-network matrix, as shown in 2 hollow spheres. Third, FeSe2 hollow spheres were encapsulated inside GC coating layer, which could effectively stabilize the surface of FeSe2 hollow sphere, thus leading to the construction of a stable solid electrolyte interphase (SEI) on it and keeping the structural integrity by additionally accommodating the huge volume expansion by Na+ diffusion, as shown in 2 nanospheres during repeated charge and discharge processes and thus maintaining the structural and electrical integrity of the structure. As a result, unique structure of the hollow nanosphere FeSe2@GC–rGO hybrid nanofibers combined the aforementioned effects of improved structural stability and maintenance of efficient electron transport pathways during long-term cycling, showing superior electrochemical performances in SIBs.These enhanced electrochemical properties of the hollow nanosphere FeSe2@GC–rGO hybrid nanofibers selected as the first target material were prepared by applying the nanoscale Kirkendall diffusion process to a conventional electrospinning process. The hollow nanosphere FeSe2@GC–rGO hybrid nanofibers showed superior sodium ion storage properties compared to those of the bare FeSe2 and nanorod FeSe2–rGO–AC hybrid nanofibers. The synergetic effects of the highly conductive GC-coated FeSe2 hollow nanospheres with high structural stability and fast and continuous transport pathways for electrons during cycling and a highly conductive rGO nano-network matrix resulted in the superior cycling and rate performances of the hollow nanosphere FeSe2@GC–rGO hybrid nanofibers. This simple synthesis method could be widely applied in the preparation of highly conductive GC-coated hollow metal chalcogenide nanospheres decorated within rGO nanofibers for a wide range of applications, including energy storage.We proposed the synthesis of a newly designed nanostructured material comprising graphitic carbon-coated hollow metal chalcogenide nanospheres decorated within rGO nanofibers. The hollow nanosphere FeSe2@GC–rGO hybrid nanofibers were prepared via a three-step process. For this preparation, Fe(acac)3-polystylene (PS)–polyacrylonitrile (PAN) with graphene oxide (GO) [Fe(acac)3–PAN–PS–GO] composite nanofibers were prepared as precursor fibers via an electrospinning process. GO was synthesized from graphite flakes using a modified Hummers method, as described in our previous report403 , 1.0 g of PAN , 2.0 g of PS , and 0.2 g of GO in a solution of 30 mL of N,N-dimethylformamide  with vigorous stirring overnight. The prepared solution was loaded at a flow rate of 2 mL h−1 into a plastic syringe equipped with a 25-gauge stainless steel nozzle. The solution was subsequently ejected and electrospun onto a drum collector covered with aluminum foil. During the electrospinning process, the distance between the tip and the collector was maintained at 20 cm, and the rotation of the drum was maintained at 100 rpm. The applied voltage between the collector and the syringe tip was 25 kV. The resultant Fe(acac)3–PAN–PS–GO composite nanofibers were stabilized at 120 °C in air for 1 h. For the FeSe2@GC–rGO hybrid nanofibers, the reduction process was conducted at 500 °C for 3 h in the presence of a gas mixture of 10% H2/Ar; this method produced metallic Fe@GC–rGO hybrid nanofibers. The subsequent selenization process was carried out at 300 °C for 6 h in H2Se gas, formed from commercial selenium-metal powders by hydrogen gas, to produce the hollow FeSe2@GC–rGO hybrid nanofibers. For the selenization process, the metallic Fe@GC–rGO hybrid nanofibers and selenium-metal powders were loaded in a covered alumina boat and placed in a quartz-tube reactor. For the FeSe2–rGO–AC (amorphous carbon) hybrid nanofibers comprising FeSe2 nanorods used for comparison purposes, as-spun Fe(acac)3–PAN–PS–GO composite nanofibers were post-treated at 500 °C for 3 h under an Ar atmosphere and subsequently at 300 °C for 6 h in H2Se gas for the selenization of the FeOx into FeSe2. Bare FeSe2 nanofibers without carbon material were also prepared as another comparison sample. Fe(acac)3–PAN–PS composite nanofibers were prepared via electrospinning with identical conditions, as described above, but without containing GO in the precursor solution. The resultant Fe(acac)3–PAN–PS composite nanofibers were post-treated at 500 °C for 3 h under an air atmosphere and subsequently at 300 °C for 6 h in H2Se gas for their selenization. For simplicity, the FeSe2–rG–GC hybrid nanofibers comprising FeSe2 hollow nanospheres, FeSe2–rGO–AC (amorphous carbon) hybrid nanofibers comprising FeSe2 nanorods, and bare FeSe2 nanofibers are referred to as “hollow nanosphere FeSe2@GC–rGO”, “nanorod FeSe2–rGO–AC”, and “bare FeSe2”, respectively.Hollow FeSeα radiation (λ = 1.5418 Å) at the Korea Basic Science Institute (Daegu). X-ray photoelectron spectroscopy , with a focused monochromatic Al Kα at 12 kV and 20 mA, was used to analyze the compositions of the specimens. The surface areas of the nanofibers were determined using the Brunauer–Emmett–Teller (BET) method, where N2 was the adsorbate gas. The structural characterization of the carbon in the specimens was performed via Raman spectra  at room temperature. Finally, thermogravimetric analysis (TGA) was performed using a Pyris 1 TGA .The microstructures of the nanofibers were observed using field-emission scanning electron microscopy  and field-emission transmission electron microscopy . In addition, their crystal structures were evaluated through X-ray diffraction  using Cu K2 nanofibers were analyzed by constructing 2032-type coin cells. Each anode was prepared by mixing the active material, carbon black, and sodium carboxymethyl cellulose (CMC) in a weight ratio of 7:2:1. Na metal and microporous polypropylene film were used as the counter electrode and the separator, respectively. The electrolyte was 1 M NaClO4 (Aldrich) dissolved in a mixture of ethylene carbonate and dimethyl carbonate , to which 5 wt% fluoroethylene carbonate (FEC) was added. The discharge–charge characteristics of the samples were investigated by cycling the cells in a 0.001–3 V potential range at various current densities. Cyclic voltammograms (CV) were measured at a scan rate of 0.07 mV s−1. The dimensions of the anode were 1 cm × 1 cm, and the mass loading was approximately 1.2 mg cm−2. The electrochemical impedance was measured using electrochemical-impedance spectroscopy (EIS) over a frequency range of 0.01 Hz to 100 kHz by using the cell taken after fully charged up to 3.0 V.The electrochemical properties of the fabricated FeSeHow to cite this article: Cho, J. S. et al. Graphitic Carbon-Coated FeSe2 Hollow Nanosphere-Decorated Reduced Graphene Oxide Hybrid Nanofibers as an Efficient Anode Material for Sodium Ion Batteries. Sci. Rep.6, 23699; doi: 10.1038/srep23699 (2016).


Korsakoff syndrome (KS) is a neurological state mostly caused by alcohol-dependence and leading to disproportionate episodic memory deficits. KS patients present more severe anterograde amnesia than Alcohol-Dependent Subjects (ADS), which led to the continuum hypothesis postulating a progressive increase in brain and cognitive damages during the evolution from ADS to KS. This hypothesis has been extensively examined for memory but is still debated for other abilities, notably executive functions (EF). EF have up to now been explored by unspecific tasks in KS, and few studies explored their interactions with memory. Exploring EF in KS by specific tasks based on current EF models could thus renew the exploration of the continuum hypothesis. This paper will propose a research program aiming at: (1) clarifying the extent of executive dysfunctions in KS by tasks focusing on specific EF subcomponents; (2) determining the differential EF deficits in ADS and KS; (3) exploring EF-memory interactions in KS with innovative tasks. At the fundamental level, this exploration will test the continuum hypothesis beyond memory. At the clinical level, it will propose new rehabilitation tools focusing on the EF specifically impaired in KS. The negative consequences of chronic excessive alcohol consumption on health are well established, alcohol-dependent subjects (ADS) presenting impairments in several body systems  clarifying the extent of executive dysfunctions in KS; (2) determining the differential deficits across specific EF in ADS and KS; (3) exploring the interactions between EF and memory impairments in KS. This thorough exploration might lead to a new model of cognitive impairments in KS, which will have crucial implications at fundamental  and clinical  levels.Severe retrograde and anterograde amnesia is the most explored symptom in KS  autobiographical memory, including general knowledge, semantic information, and personal events  to some classic and/or complex tests routinely used to assess EF Using specific EF tasks: future studies should use tasks evaluating each basic EF components , e.g., the nine Miyake’s tasks Systematically comparing ADS and KS: exploring and comparing thoroughly EF in KS, ADS, and healthy participants will step up the actual knowledge on this topic. Besides the nine tasks presented above, a specific exploration of inhibition subcomponent might be proposed Directly testing EF-memory interactions: the interaction between basic executive factors and retrieval memory process should be directly tested among KS and ADS. The Stop-Signal Task could be tailored to include a learning aspect based on classic memory learning task (e.g., California Verbal Learning Test; Elwood, On the basis of studies presented above and questions held in abeyance, the possible line of approach for future studies will now be described by showing how EF may constitute a relevant research focus in the exploration of memory deficits in KS. This research approach is summarized in Figure To conclude, this perspective paper underlined the usefulness of developing more specific tasks to explore EF in KS. At the fundamental level, comparing ADS and KS performances with the above-mentioned tasks would clarify the debate on the continuum hypothesis by determining its validity for each EF and for EF-memory interactions. At the clinical level, a straightforward examination of EF process would identify the differential deficits in KS and lead to specific rehabilitation proposals already applied in ADS, e.g., cognitive enhancement (Sofuoglu et al., The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


To effectively and accurately detect and classify network intrusion data, this paper introduces a general regression neural network (GRNN) based on the artificial immune algorithm with elitist strategies (AIAE). The elitist archive and elitist crossover were combined with the artificial immune algorithm (AIA) to produce the AIAE-GRNN algorithm, with the aim of improving its adaptivity and accuracy. In this paper, the mean square errors (MSEs) were considered the affinity function. The AIAE was used to optimize the smooth factors of the GRNN; then, the optimal smooth factor was solved and substituted into the trained GRNN. Thus, the intrusive data were classified. The paper selected a GRNN that was separately optimized using a genetic algorithm (GA), particle swarm optimization (PSO), and fuzzy C-mean clustering (FCM) to enable a comparison of these approaches. As shown in the results, the AIAE-GRNN achieves a higher classification accuracy than PSO-GRNN, but the running time of AIAE-GRNN is long, which was proved first. FCM and GA-GRNN were eliminated because of their deficiencies in terms of accuracy and convergence. To improve the running speed, the paper adopted principal component analysis (PCA) to reduce the dimensions of the intrusive data. With the reduction in dimensionality, the PCA-AIAE-GRNN decreases in accuracy less and has better convergence than the PCA-PSO-GRNN, and the running speed of the PCA-AIAE-GRNN was relatively improved. The experimental results show that the AIAE-GRNN has a higher robustness and accuracy than the other algorithms considered and can thus be used to classify the intrusive data. Network security has become increasingly significant with the development of the Internet. Because of the diversity and complexity of intrusion methods, it is difficult to effectively detect the traditional firewall technique. Network intrusion detection, such as neural networks, appeared at a historic moment –3. The eThe traditional intelligent algorithms of data regression and classification, such as the traditional GRNN , fuzzy CThis study was devoted to exploring a new combinatorial neural network to rapidly determine the intrusion types. Both GRNN and AIAE perform better than their related algorithms. Their combination may produce better results and improve the efficiency of intrusion detection. In addition, the combination of the AIA and neural networks is an important part of algorithm studies . CurrentY and dependent variable x, is to calculate y, which has the maximum probability values. Assuming that f is the joint probability density function of the random variables x and y, the observed value of x is X. Thus, the regression of y relative to X isY when the input is X.GRNN is a radial basis function neural network that is composed of an input layer, pattern layer, summation layer and output layer. Its theoretical basis is the nonlinear regression analysis. The essence of the regression analysis, which is composed of the independent variable Xi and Yi are the observed values of the random variables x and y; n is the sample size; p is the dimension of x; and σ is the width coefficient of the Gaussian function, which is called the smooth factor.The density function f is substituted by BecauseYi. Each weight factor of Yi is the index of the squared Euclidean distance between Xi and X. When σ is notably large, σ approaches 0, σ directly determines the predictive accuracy of the GRNN [the GRNN , 21.The AIA and GA have similar structures: they consist of the operations of selection, crossover and mutation. Unlike the GA, the quality of individuals (antibodies) is evaluated using the affinity (fitness) and concentration in the AIA, which reflects the diversities of the real immune systems. However, the only evaluation index of the GA is the fitness . Thus, tThis study used the elitist-archive and elitist-crossover strategies to prevent the loss of the current optimal individuals in the next generation of the population.Definition 1: In the elitist-archive strategy, the individuals with the maximum fitness, which are called the elitists, must not perform the selection and mutation operations when the experiment begins. The elitists will survive with the selective probability of 100% in the next generation, and they will not be damaged by the selection, crossover and mutation operations. To maintain the scale of the population, the individuals with the minimum fitness will be eliminated if the elitists are added into the next generation .Definition 2: In the elitist-crossover strategy, the elitists should be crossed with the chosen individuals in the population according to a pre-set elitist-crossover probability in addition to the traditional crossover; thus, the genetic structure of the population can be improved. The theory supporting this strategy is provided in Tan GZ et al. . The numPrincipal component analysis (PCA) is a type of technology that can analyze and simplify data sets. The dimensions of the data sets can be decreased by reserving the low-order principal components and neglecting the high-order ones; simultaneously, the characteristics with the largest contribution for the variances in the data sets are reserved. Such low-order components can reserve the most important aspects of data. However, because the PCA is extremely sensitive to extrema and missing values, these factors may produce missing or incorrect results , 37. ThuThis paper introduces an AIAE-GRNN algorithm to improve the detection accuracy. The mean square errors (MSEs) of the network model created by the GRNN were taken as the affinity functions. The smooth factors were optimized by iterating the AIAE until the algorithm satisfied the terminal condition. The smooth factor that was solved at this time is the optimal one. Then, the GRNN with the optimal smooth factor was used to classify the intrusion data. The algorithm flow chart is shown in Step 1: Data preprocessing. To eliminate the magnitude differences among the data of each dimension and improve the classification accuracy, the intrusion data could be normalized into the figures in −. BecauseN, crossover probability Pc, elitist-crossover probability Pck and mutation probability Pv, were set. The running parameters of the algorithm, such as the maximum iterations and capacity of the memory bank, were also set.Step 2: Antigen recognition. The affinity functions, which were the antigens in the immune system, were set as the MSEs of the output values and actual values in each generation of the GRNN. The initial parameters of the antigens, such as the population size N smooth factors were randomly produced as the initial solutions.Step 3: Production of the initial antibodies. Step 4: Calculation of the antibody affinities. The intrusive data were plugged into the GRNN after normalization; then, the output values of the MSE in this generation were produced.Step 5: Elitist archive. The current individuals with the largest affinities were preserved in the memory bank as memory cells in a certain proportion. Each antibody affinity was calculated, and if all current antibodies had lower affinities than elitists, the antibodies with the lowest affinities would be replaced by the elitists. Then, the algorithm continued to Step 6. In contrast, if some antibodies had higher affinities than the elitists, these antibodies would replace the elitists with the lowest affinities in the population; then, the algorithm would repeat Step 4.Step 6: Judgment of the loop's termination condition. If the algorithm achieved the maximum iterations, it would be terminated and output the current smooth factor. Then, the smooth factor would be an input of the trained GRNN to classify the intrusive data. Otherwise, the algorithm would continue to Step 7.Step 7: Calculation of the antibody concentration and expected breed rate. Each antibody concentration and expected breed rate would be calculated according to the computing methods of Hajiaghaei-Keshteli M .Step 8: Selection. The algorithm would perform the selection operation. The probability of the individuals under selection was the expected breed rate, which had been calculated.Pc; then, the elitist-crossover operation would be performed on the individuals in the population using the methods of the previous study [Pck of the operation was notably low.Step 9: Crossover and elitist crossover. The population would be crossed with probability us study , and thePk; then, the affinities of the variant individuals would return to Step 4 to be calculated again.Step 10: Mutation. The mutative positions, which were randomly selected, would be mutated with probability The experimental environment was based on Microsoft Windows 7. The hardware environment was Intel Core i5-3230M, 2.60 GHz and RAM 4 GB, and the simulation software was MATLAB 2012b . The experimental data were divided into the training data  and the N of each algorithm was 30; the crossover probability Pc and mutation probability Pv of the AIAE and GA were 0.5; the two acceleration factors of PSO, i.e., c1 and c2, were 2; the AIAE evaluation diversity was 0.95; the capacity of the memory bank was 10; and the elitist-crossover probability Pck was 0.05. The definitions of DR and FPR are as follows [In addition to the AIAE-GRNN, the study selected two common GRNN combinational algorithms, GA-GRNN and PSO-GRNN, as the controlled trials, and FCM was the control sample. In fact, the convergence of FCM is directly related to the selection of the weighting exponent. The value of the weighting exponent in the traditional FCM must be chosen by experience; thus, the human factors will seriously affect the performance of the FCM . This fa follows :Definition 3: The detection rate (DR) is the probability that the detection systems can correctly give an alarm when the monitoring systems are attacked.Definition 4: The false positive rate (FPR) is the probability that the normal instructions are mistakenly considered intrusion instructions, and an alarm is given.th iteration, the values of the GRNN smooth factors continue to change by a large margin, which shows that it has a worse local search ability than the AIAE-GRNN and PSO-GRNN and a lower classification accuracy than the AIAE-GRNN. Although the traditional FCM has a short running time, its classification accuracy is not comparable with other intelligence algorithms, which results in a difficult classification . PCA can reduce the dimensions of the training samples and training time , but theThe value of the maximum iteration was 30, and other parameters were identical to those in the previous paragraphs. The DR and FPR of the two networks are shown in From The study introduced a method of network intrusion detection using the AIAE-GRNN. The AIAE-GRNN has a higher classification accuracy but longer running time than two types of GRNN combinational algorithms and FCM. To decrease the running time and prove the robustness of the network, this study used PCA to reduce the dimensions of the intrusive data, which effectively reduced the training time of the network. In the contrast test, which contained PSO-GRNN that was similarly processed with PCA, the classification accuracy of AIAE-GRNN with the shortened running time is barely affected, and the AIAE-GRNN has better convergence than the PSO-GRNN. This result indicates that the AIAE-GRNN is not notably sensitive for the training samples and shows a good robustness. The PCA-AIAE-GRNN balances the classification accuracy and running efficiency, and can therefore be used in intrusion detection or other fields. Although the AIAE-GRNN has many merits, the AIAE has a lower running speed than PSO and other intelligence algorithms. Optimizing the time complexity of the AIAE-GRNN will be critical to improving the network performance and must be studied further.S1 Table(DOC)Click here for additional data file.S1 Dataset(XLS)Click here for additional data file.S2 Dataset(XLS)Click here for additional data file.


Dopamine is an inhibitory neurotransmitter involved in the pathology of schizophrenia. The revised dopamine hypothesis states that dopamine abnormalities in the mesolimbic and prefrontal brain regions exist in schizophrenia. However, recent research has indicated that glutamate, GABA, acetylcholine, and serotonin alterations are also involved in the pathology of schizophrenia. This review provides an in-depth analysis of dopamine in animal models of schizophrenia and also focuses on dopamine and cognition. Furthermore, this review provides not only an overview of dopamine receptors and the antipsychotic effects of treatments targeting them but also an outline of dopamine and its interaction with other neurochemical models of schizophrenia. The roles of dopamine in the evolution of the human brain and human mental abilities, which are affected in schizophrenia patients, are also discussed. PPI ophrenia . NMDA- aophrenia . GABA isophrenia . Activatophrenia , 41, andophrenia . In a raophrenia . Changesophrenia , 45. Howophrenia  indicateophrenia . Howeverophrenia . Therefoophrenia ]. Socialophrenia .1A-receptors in the prefrontal cortex, which results in increased dopamine activity -receptors in the prefrontal cortex -receptor activity in the prefrontal cortex and, subsequently, better cognitive abilities in carriers of the Met-allele –82. A liin vitro binding experiments , D (2), D (3), and D (4)-receptors . D (1) reriments . The acteriments . Dopamineriments . This ineriments . This speriments , 106. Aleriments , the meceriments . Antipsyeriments , particueriments . Glutamaeriments , 112. Foeriments  or by theriments  have beeeriments , 115, wheriments ; Remingteriments , systemaeriments ; Seeman eriments ]. The ateriments ]. Schizoeriments ]. Lower eriments , 122. Thi et al. ]. D (1)-i et al. . Furtheri et al. . NMDA ani et al. . D (1)-ri et al. . For exai et al. .2/NMDA receptor mosaics have also been found in the ventral striato-pallidal GABA neurons. Decreased D (2)-receptors in the thalamus and anterior cingulate cortex in schizophrenia might suggest that they are involved in abnormalities in dopamine transmission from the thalamus to the prefrontal cortex (A slightly increased density of D (2)-receptors in basal condition and a significant increase in D (2)-receptors in the striatum of schizophrenia patients has been found . This inl cortex .Low doses of D (2)-receptor antagonists and signaling enhancers of NMDA-receptors are recommended as new treatments in schizophrenia [review by Fuxe et al. ]. In theIt can be summarized that, to date, the mechanism of every effective antipsychotic medication in schizophrenia involves dopamine and its interaction with other neurochemical pathways such as those of glutamate, GABA, serotonin, and acetylcholine.Deviations in dopamine and glutamate have been reported in the prefrontal cortex of schizophrenia patients . NMDA-reThe finding by Brisch et al.  that astB-receptor activity, glycine reduces the release of dopamine by modulating DAT-type transporters in the prefrontal cortex and striatum  possessing 5-HT-Tancredi ]. It canTancredi , 184–189Tancredi ; Alex anTancredi ; McCrearTancredi ; BhattacTancredi ; MeltzerTancredi ; McMahonTancredi ; Gao et Tancredi ].A receptor complex activity, as well as dendritic spine loss in the prefrontal cortex  that aided dopaminergic expansion –223. Dopprimates . In humaprimates .Homo erectus onward, humans became persistence hunters, requiring various morphological and thermo-regulatory modifications , which provides approximately 20% energy return during running, elastic tendons, short toes, more pronounced gluteus maximus muscle, long legs, CNS coordination of metabolic, and cardio-vascular responses to sustained running (Homo erectus onward there is an evident increase in stride size, which also optimized ergonomic requirements of bipedalism while diminishing energy requirements. Greater mass of slow twitch muscles would have also assisted long distance locomotion. Long distance locomotion in conjunction with greater hunting activities in ancestral hominins incorporated all aspects of the CNS such as retention and memory recall of large geographic areas, which maximized resource acquisition. The locomotion/behavior interplay, which was mediated by nerve cells and the dopaminergic system may have evolutionary expanded cortical regions and neuro-hormonal organization in ancestral hominins (Recent research suggests that from  running . From Hohominins .The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Waddington coined the term “epigenetic” to attempt to explain the complex, dynamic interactions between the developmental environment and the genome that led to the production of phenotype. Waddington's thoughts on the importance of both adaptability and canalization of phenotypic development are worth recalling as well, as they emphasize the available range for epigenetic action and the importance of environmental feedback (or lack thereof) in the development of complex traits. We suggest that a dynamic systems view fits well with Waddington's conception of epigenetics in the developmental context, as well as shedding light on the study of the molecular epigenetic effects of the environment on brain and behavior. Further, the dynamic systems view emphasizes the importance of the multi-directional interchange between the organism, the genome and various aspects of the environment to the ultimate phenotype. Waddington introduced the term epigenetics in 1942 , or by less clearly delimited inputs and more continuous inputs, such as parental behavior.Molecular epigenetics has changed all that with its sitting-on-top-of-role operating on genes and its openness to influences from the surrounding environment. Waddington would have loved the discovery but perhaps not as much as we love it. After all he was already committed to the multiplicity of environmental factors along with dynamic changes in the organism as the organism became more organized—canalized. But maybe not, since love blinds us to many things. Nonetheless we will to try to cut away the blinders just a bit. In so doing we will be building not only on the work of Waddington, but of many others, notably Gottlieb , and attWaddington's epigenetics, like molecular epigenetics is was anchored in evolutionary theory. Nonetheless, molecular epigenetics govern shorter term ontogenetic processes that can operate on a fast time scale (even minutes) to ontogenetic time (a lifetime), and likely, for some even, intergenerationally. Indeed one way to see the functional role of molecular epigenetics is that it is a way for the organism to make “quick” adaptations to the changing circumstances. Indeed, Waddington spent much ink arguing that “adaptability” was an important adaptation in-and-of-itself and that it was epigenetic in nature -phenomenon. What we think is needed is as much effort into characterizing the details of the experience of the animal or human and its environment as has gone into characterizing molecular mechanisms.It is established that enriched environments are protective against the effects of stress upon the brain in laboratory animals  over time. With the exception of work on non-human primates, few molecular epigenetic studies characterize animals' forms of engagement with the environment, particularly the social environment, with equal quality to that of developmentalists. Moreover, developmentalists have a deep concern for longitudinal studies, studies that are sorely lacking in recent animal work.As to the lack of access to brain tissue, human work will always lag. Nonetheless human studies have non-invasive ways of examining brain function in the engaged individual. These techniques may reveal equivalently valuable information as do neuroanatomical studies of sacrificed animals. Also, human studies often employ measure of other systems, the autonomic nervous system, the immune system, the cardiac system, the neuroendocrine system. These approaches are possible in animal systems, but are not often pursued for methodological and economic reasons, as well as disciplinary canalization. Though not necessarily at the molecular level, the evaluation of these systems exposes underlying mediating processes or proximal pathways which are systems that affect molecular epigenetic changes. Indeed from a dynamic systems perspective, making brain tissue examination the gold standard along with molecular processes may be mistaken since the outcome of any manipulation is the result of multilevel interactions over time. Nonetheless, given the centrality of the brain to the developing organism's interaction with the environment, work on this organ is of substantial importance if it can be done with an equally rigorous eye to the environment. Animal studies will be important in this regard, both due to the ability to make observations at the molecular level in brain tissue and the ability to control the developmental environment in detail. While not flashy, there is a real need for descriptive studies of the brain epigenome during normal development as well as rigorous studies of how specific environmental interventions influence a broad range of molecular epigenetic marks in the brain.We utilize the two models  wrote and conceived of this perspective.Dr. ET acknowledges the support of the NIH: 1 R01 HD083267-01 and NSF 1457111.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Gliomas, the most frequent tumours occurring in the CNS, are defined and graded on the basis of histological features to predict prognosis and management. Owing to biological heterogeneity, the histological diagnosis and expected clinical outcome do not match in a significant number of patients. The combination of imaging and gene expression, referred to as “radiogenomics,” has the potential to give insight into tumour biology that would be difficult to acquire from either technique alone.• Throwing light upon individual imaging feature and biological/ molecular alterations, analyses that may detect subsets of morphologically identical tumours with different clinical behavior (diagnostic markers).• Classification and grading of Gliomas as per Haarlem consensus.• Imaging features of glioblastomas may correlate with molecular mutations.• Identification of imaging parameters that has the potential as a non-invasive biomarker for common molecular mutations associated with gliomas and their associated clinical impact.• Review of current radiogenomics literature.• Given the noninvasive nature of medical imaging and its wide use in clinical practice this approach facilitates the association of complex molecular signatures with readily identifiable imaging characteristics.• As we move toward a more individualised approach to therapy for glioblastoma on the basis of its specific genetic and biochemical features, radiologists may contribute to the future development of targeted agents for treatment of glioblastoma.


While interdisciplinarity continues to increase in popularity among funders and other scientific organizations, its potential to promote scientific advances remains under-examined. For HIV/AIDS research, we examine the dynamics of disciplinary integration (or lack thereof) providing insight into a field's knowledge base and those questions that remain unresolved. Drawing on the complete histories of two interdisciplinary journals, we construct bibliographic coupling networks based on overlapping citations to identify segregation into research clusters and estimate topic models of research content. We then compare how readily those bibliographic coupling clusters account for the structuring of topics covered within the field as it evolves over two decades. These comparisons challenge one-dimensional and/or cross-sectional approaches to interdisciplinarity. Some topics are increasingly coordinated across disciplinary boundaries ; others remain relatively segmented into disconnected disciplinary domains for the full period . This divergence indicates heterogeneity in interdisciplinarity and emphasizes the need for critical approaches to studying the organization of science. Many contemporary global problems transcend disciplinary boundaries imposed by institutions of higher education. Solutions to problems such as poverty, conflict, resource depletion, or disease likely demand interdisciplinary collaboration. HIV/AIDS research, for example, does not belong to any single discipline, with scientists making important contributions from a range of basic, clinical, social and applied sciences The stakes of interdisciplinarity remain high because poor coordination could limit the potential for important scientific advances. Additionally, large societal investment is banking on the success of these approaches. In socio-medical research, successful communication can result in strategies to improve population health outcomes how integrative efforts in problem-based areas of science successfully navigate these processes of disciplinary integration.Scholars studying the structure of scientific production have long-recognized the importance of informal interactions, including citation practices, which bridge traditional disciplinary boundaries for shaping the content and progress of fields Recent work demonstrates the utility of scientometric approaches for accounting for boundary structure and dynamics to examine the whole of science AIDS and JAIDS – from their respective first issues through the end of 2008. This includes a total of 16,907 published items . We retrieved the full bibliographic information (including complete cited references lists) and abstract text for each of these items from ISI Web of Science. Analyses address this complete corpus and each journal separately. To identify the structure and content of research communities in the AIDS/JAIDS corpus, we combine bibliographic coupling networks with topic models, presenting results for the complete time-collapsed corpus  and a series of time-based moving windows to examine the evolution of patterns over two decades.Our data come from all published articles, letters and notes in the two top interdisciplinary journals for HIV/AIDS research – First, for each pair of papers in the corpus, we construct a paper-to-paper bibliographic coupling network Second, we analyze those networks with community detection approaches, which identify segmentation within a network content of science is also essential to understanding interdisciplinarity, we generate a topic model for the abstract texts in the corpus. Topic models consist of a class of techniques that locate structure in unstructured text corpora Third, since the nor under- representation across clusters) suggests that clustering is not at all topic-related. Underrepresentation alone can help identify topics that are not salient for the development of particular bibliographic coupling clusters, while consolidation is marked by topics with high over-representation in one cluster and underrepresentation in others. Lastly, those single topics that are over-represented in multiple clusters lack integration in that the same topics are being covered in clusters that are not drawing upon the same literatures to develop ideas within them – i.e., are more multidisciplinarily organized. In combination, these approaches allow us to identify how segmented or consolidated the HIV/AIDS research field is, and how disciplinary boundaries contribute to that structuring, in part by identifying which topics are well-bounded within single research communities versus those that span across several.Fourth, we compare how readily these topics are contained within or bridge across the identified bibliographic coupling communities. We do this with residual contingency analyses for categorical independence, which we visualize with mosaic plots Moreover, by examining how this alignment shifts across the observed window, we can identify whether and how patterns of integration differ for “resolved” research questions compared to “open” questions. To do this, we compute community detection solutions and the correspondence analyses for the collapsed complete corpus , and separately over a series of moving windows that capture relevant “epistemic periods.” These moving windows are labeled by the year at the end of the window and extend backwards for 4 years, which represents the median citation age within this corpus; “Citation age” is the difference (in years) between the date of the citing paper's publication and the year of publication for each of its cited references AIDS and JAIDS . The network is clustered into distinct communities (modularity = 0.469), and is dominated by three primary communities , with several smaller communities that are peripheral to one of those 3  or two of those larger communities . As of 1999, both journals introduced article classifications of “Basic,” “Clinical” or “Social and Epidemiological” Sciences, which were applied to the vast majority of subsequently, published articles. The correspondence between the three largest bibliographic coupling network communities and these broad “discipline” like labels is pronounced (presented in Panel D) - with each community dominated by one such label . The identified discipline-based arrangement of communities is not dependent on which community solution is used. A 3-community solution was also identified which only exacerbates this pattern. Similarly, solutions with larger numbers of communities were nested within those presented, i.e., making finer divisions within, not bridging across the discipline-based communities. The emergent communities based on citation overlaps provide initial indication of the persistence of disciplinary boundaries based on the broad categorizations—basic, clinical, and social/epidemiological scientific—within this cross-sectional view. A dynamic approach that considers topic consolidation complicates this initial overview.First, we present the bibliographic coupling based communities identified for the complete 20-year window collapsed into a single network. Next we ask how these observed communities account for primary drivers of the modularity between HIV/AIDS research areas. The article labels mentioned above hint at some of those bases , but to formalize this further, we examine how readily the bibliographic coupling community structure corresponds with the 30 identified topics that summarize the content of HIV/AIDS research see .It is potentially problematic to consider two decades of HIV/AIDS research as a single corpus. The field has advanced rapidly since these journals were founded in 1988/9 and clustering may have evolved across the observed period. AIDS and JAIDS are closely aligned, with changes in JAIDS lagging behind those in AIDS for roughly the first half of the period, but happening more simultaneously for the latter half.The first noteworthy pattern in Moving to how the bibliographic coupling aligns with the substantive content of the field over time, Additionally, by overlaying these changes with the “discipline” like labels from above (which is represented by colors beginning in 2001), we can see what accounts for the structure and dynamics of the changing clustering patterns  disciplines, regardless of the topic.The differences in topics' distributions across these clusters are also informative. Some topics retained a relatively consistent pattern over the evolving clustering structure , others remained within a single consolidated cluster, but the disciplinary composition of that cluster changed through time . Others became more consolidated over time , or remained distributed over multiple communities .While the description above has largely focused on field-level organizational dynamics, the reality is that these patterns are the result of individual- (or research team) level research processes. Those topics marked by consolidation suggest areas where research content drives the literature(s) upon which authors draw in formulating ideas and developing projects. For others , it appears that disciplinary boundaries are more likely to shape knowledge production - potentially missing ideas that develop on the same topic, but within another cluster dominated by other disciplines. This leads to the potential of missing key ideas that develop in other (disciplinary) portions of the literature. In sum, the general pattern within HIV/AIDS research is one increasingly marked by disciplinary segmentation rather than integration, while particular topics vary considerably in how closely they adhere to that overall pattern.The trajectory of interdisciplinary research, such as found in the HIV/AIDS field, is not predetermined. We cannot know from the outset whether a knowledge project will grow more interdisciplinary or will shrink back into disciplinary boundaries. This ambiguity is even more pronounced when considering research fields with heavy investments as various key players may have incentives to prevent or expand integration. The models employed here provide a means for examining the multidimensional and dynamic processes that enable evaluation of progress within interdisciplinary frameworks.S1 FigurePerplexity Scores by Number of Topics. This figure presents the optimization information for the number of topics identified within the corpus.(TIFF)Click here for additional data file.S2 FigureTopic Label Contributions by Proportional vs. Top Topic Assignment. This figure compares the contribution to the overall topic distribution of each of the 30 identified topics. The comparison is between assigning each paper proportionally to the complete set of topics it is identified with versus assigning each paper only to the single topic it is most closely identified with.(TIFF)Click here for additional data file.S3 FigureComplete Correspondence between Clusters and Topics. This figure presents the correspondence analysis for all 30 topics and all 6 clusters. It adds the information for the 17 consolidated topics that are excluded from (TIFF)Click here for additional data file.S4 FigureEvolution of Relationship between Clusters and Discipline-Like Labels. This figure provides the correspondence between the identified clusters and the broad discipline-like labels separately for 5-year moving windows – the dynamic version of (TIFF)Click here for additional data file.S5 FigureEvolution of Relationship between Clusters and Topics. This figure provides the correspondence between the identified clusters and identified topics separately for 5-year moving windows – the dynamic version of the mosaic plots in (PDF)Click here for additional data file.S1 TableTopic Labels and Brief Descriptions. This table presents the full list of identified topic labels, and briefly describes the content included in each of those topics.(PDF)Click here for additional data file.S1 TextDescription of Supplementary Analyses. This section provides description of the methods for several ancillary analyses that support the details presented in the manuscript text.(PDF)Click here for additional data file.


The program allows fast and easy building and/or editing different molecular structures, up to several thousands of atoms large. Luscus is able to visualise dipole moments, normal modes, molecular orbitals, electron densities and electrostatic potentials. In addition, simple geometrical objects can be rendered in order to reveal a geometrical feature or a physical quantity. The program is developed as a graphical interface for the MOLCAS program package, however its adaptive nature makes possible to use luscus with other computational program packages and chemical formats. All data files are opened via simple plug-ins which makes easy to implement a new file format in luscus. The easiness of editing molecular geometries makes luscus suitable for teaching students chemical concepts and molecular modelling.The novel program for graphical display and editing of molecular systems, The online version of this article (doi:10.1186/s13321-015-0060-z) contains supplementary material, which is available to authorized users. Visualisation of various data in theoretical chemistry plays an important role in the conduction of modern scientific research in the field. Computational possibilities of modern software routinely used in the quantum chemistry and the molecular mechanics and dynamics (MM/MD) can handle very large molecular systems containing hundreds or thousands of atoms. Without advanced graphical tools, designed for a specific branch of computational codes, it is very complicated task to create an input and proceed with calculations.Although the majority of graphical user interface (GUI) programs used in quantum chemistry have a focus on the preparation of initial molecular geometry, the post processing and visualisation of the results is also extremely important. This is especially the case if the study can not be performed as a “black box” calculation. Many advanced computational techniques, for example, multiconfigurational methods in quantum chemistry , requireGraphical user interfaces used in quantum chemistry (and in MM/MD simulations) can be classified as a general tools (not connected to any particular code), or specific to some particular computational code. The first group includes molden , rasmol Luscus is a novel program for molecular modelling and analysis of results from quantum-chemical program packages. The graphical interface is designed and is written to match computational package, MOLCAS [luscus communicates with a computational code via transparent and simple interface allowing easy integration with other programs as well, which makes it a universal tool for computational chemists. Luscus uses external plug-ins for reading and writing files. These plug-ins are usually simple programs (or scripts) which are performing simple tasks of converting data from one format to another. This technology increases the flexibility, since implementing a new format for a file with chemistry related data can be done without changing of GUI, but by adding or modifying of the corresponding plug-in., MOLCAS ,9, whichluscus code is the portability and the minimal dependence on external graphical libraries. It leads to a light-weighted graphical program which can be easily installed on virtually any platform.Another consideration we used in the design of Luscus is easy to learn and easy to use program. It is based on GV [ed on GV ,11 code,luscus code on all common computer platforms and operating systems. These libraries make possible interaction with the molecular model displayed on the screen.User interface is created with the gtk+ library, and 3D visual display is made with the OpenGL programming library. These libraries have become widespread, on many architectures, and this commonness ensures the portability of There are various file formats that become the standard in different areas in chemistry, for instance PDB file format for biomolecules and CIF file format for crystallographic data. In computational chemistry, in contrary, the standardisation of data formats is still far away from the completion . The mosThe most widespread file format in computational chemistry is so called XYZ file, which is used for the definition of atomic Cartesian coordinates. This file format has a limited usability since it can store only trivial information about molecular geometry. The format is lacking the support of dummy atoms, environment (e.g. atomic charges), and other molecular properties.luscus and computational software, which is based on XML mark-up. These files can either be produced directly by the MOLCAS code, or converted from the MOLCAS output files using corresponding plug-ins in luscus.We introduced a new file format for interaction between luscus program interprets the data blocks in the file and renders them on a screen. The new format was created as a simple, human readable and editable file. The luscus file format follows XML/CML format[luscus file format can be regarded as a XML extension to the graphical representation of chemical data. The file header, however is an exception and is identical to the XYZ file. This makes a great advantage since XYZ file format is the most accepted chemical file format in molecular graphics programs, so those programs can interpret the initial portion of the luscus file as XYZ file. The another advantage of this solution is that any XYZ file is a valid luscus file .The main purpose for introducing new file format is the transfer and the storage of visualisable data from MOLCAS,9 in a sML format-16 whereluscus file format is given in supplement [see Additional file An example of luscus is designed as a graphical interface for the MOLCAS program package, computational codes with other chemical formats can be interpreted by luscus after they are converted by the corresponding external plug-in. When a file is opened, luscus executes a plug-in, waits until it converts the file to the luscus format and opens it. Information about all available plug-ins  is stored in a configuration file and can be customised by the user. Luscus can automatically determine file type according to the data in the configuration file or alternatively, the file type can be specified by the user. The process of the conversion of file formats is done automatically without interference with user. An example of plug-in script that uses Openbabel [Although penbabel  for openpenbabel .luscus file to the custom file format. The third kind of a plug-in uses the data stored in a luscus file, create an input for a computational code, run the calculation, and finally transform the output back to the luscus format. Since luscus can detect changes in input files, the result will be automatically displayed on the screen.Plug-ins can be used for saving files as well. In the latter case, plug-in converts luscus is the fast visualisation on a screen, luscus is also capable to produce printing quality images of molecular systems. Many features, e.g. colour scheme, are adjustable and can be saved for a future use.Although the primary goal of All atomic data in luscus are dynamically allocated, so there is no hard limit for the number of atoms, however the practical limit depends on the computer processor and the graphic card. Some functionalities like displaying molecular orbitals can make an additional load on the computer graphical system and thus reduce the practical limits. The authors successfully created an image of a system with 9360 atoms with electron density and electrostatic potential data  is selected, all operations are performed for this centre. In the same way, if a bond or an angle is selected, it becomes the main focus for editing operation.Visualisation and on screen editing of atomic coordinates is an essential part of any GUI in computational chemistry. The main concept of the editing of atomic coordinates in New molecular geometries can be build (or existent geometries can be modified) by adding one by one atom, by adding a predefined molecular fragment, or by replicating existing atoms through a symmetry operation. Predefined molecular fragments are stored in separate files and users with modest computer knowledge can easily add additional fragments or modify the existent ones.Luscus can visualise structures and chemical properties, which include more than one set of Cartesian coordinates, such as trajectories, reaction coordinates and other dynamical properties. Luscus has the ability to read normal modes from the energy Hessian calculations and visualise vibrations in a form of animated movements. Structures from several files can be shown in the same orientation, and size, since this information can be saved and retrieved upon opening another file.The most common definition of molecular geometry, Cartesian coordinates are not convenient for building and editing molecular geometries since it is hard to imagine spatial relations of atoms in terms of numerical values of Cartesian coordinates. Even if simple operations in Cartesian coordinates are applied in the graphical interface, the exact positioning of atoms in a molecule can still pose a challenge since two-dimensional image of the modelling molecule on a screen lacks the depth. Several graphical programs  allow moDefining molecular geometry in terms of internal coordinates, assembled in Z-matrix is more simple task than evaluation of Cartesian coordinates for the most of the molecules, since it involves dealing with common chemical concepts like bond lengths, angles and dihedral angles. Some most popular molecular editors ,5,18 havluscus is defined in Cartesian coordinates, however editing is performed in internal coordinates. Internal coordinates are being adjusted with partial Z-matrices that are defined ad-hoc, by selecting atoms and thus these coordinates are not depending on the order of atoms, as in conventional Z-matrix editors. In luscus it is possible to modify any interatomic distance by selecting two atoms. Relative orientations of atoms can be adjusted by changing a valence angle or a torsional angle by selecting three or four appropriate atoms. The atom that is selected first is displayed with a different colour than other selected atoms and this atom is being moved by adjusting an internal coordinate. Editing operations can be applied either to a single atom, or to a group of atoms. In order to connect several atoms into a group one can use on screen marking by mouse , or one can use a graphical interface to determine the group . When a group is defined, all operations will be performed for all atoms belonging to this group.Molecular geometry in The flexibility of editing molecular systems can be extended by introducing dummy atoms as pivot points. In that way all operations can be performed around pivot points that are not part of the molecule itself.Luscus also supports editing in Cartesian coordinates through a Cartesian editor. This editor supplements the aforementioned method of editing molecules in internal coordinates.Luscus can use external computational programs  to modify coordinates, for example, to perform the geometry optimisation.luscus are implemented as a building tool, that replicates existent atoms into symmetrically equivalent positions. Luscus brings novel feature of performing a symmetry operation applied for the selected atoms only. That feature is very useful since many molecules have at least one symmetric part. Symmetry operations available are: inversion through a point (if one atom or dummy atom is selected), translation and a proper rotation around an axis (if two atoms are selected), and finally a reflection through a plane (if three atoms are selected). In cases where a symmetry operation can’t be realised with existing atoms (pivot points), additional dummy atoms can be temporarily introduced.Symmetry operations become a common feature in some graphical chemistry programs that can certainly make easy building molecular structures. Symmetry operations are usually implemented as a tool for symmetrizing already build molecular structures  that movThe use of symmetry can be demonstrated by the example of building naphthalene molecule from benzene. First, two hydrogen atoms are deleted, and the corresponding C-C bond is selected. Naphthalene structure is created by applying a rotation by 180 degrees. The same effect can be achieved, if a dummy atom is introduced in the middle of the C-C bond and the inversion operation around the dummy atom is applied.luscus uses a threshold in order to make a decision if two atoms are identical or not. This feature can be used for symmetrizing a molecule, or its part.In order to apply a symmetry operation, luscus can enforce the planar symmetry by selecting three atoms and applying mirror reflection.For example, if during a geometry optimisation some atoms in benzene ring move out of the plane, luscus will keep only one of them (in an average position), aligning the chosen part of the molecule according the symmetry element.If some atoms are copied to the location that is too close to an existing atom, luscus can determine a symmetry group of a molecule.In addition to applying symmetry operations, Luscus allows drawing simple geometrical objects as a convenient way of emphasising a geometrical feature or a physical property in the molecular structure. For instance arrow is implemented to illustrate the dipole moment of a molecule and is displayed by default on files that provide information about molecular dipole. Other potential uses are: illustration of atomic or molecular movement, dative bond, reaction coordinate etc. All geometrical objects can be defined through a number of selected atoms, as in the case with symmetry operations. Luscus can draw arrows, spheres, plains, triangles, and parallelepipeds. Defining points are not restricted to the atoms present in the molecule since a temporary dummy atoms can be introduced at any time. The geometrical objects can be combined in order to draw more complicated ones, for instance a square can be drawn from two triangles. Geometrical objects are rendered as translucent since many of them enclose a volume of space and might contain atoms inside. However, the opacity as well as colour can be adjusted.luscus is its ability to visualise molecular orbitals and electron densities. The need for such feature arose with the MOLCAS program package. The MOLCAS program package is well known for multiconfigurational computational models. In this models, it is often necessary to visually inspect orbital in order to determine its nature [luscus. This feature enables fast and easy performing of otherwise cumbersome task of setting orbitals into the orbital subspaces. In order to make orbital selection even more easier, all orbitals are listed together with their symmetry, energy and occupation numbers. In a large list of orbitals, user can temporarily hide orbitals from the list or can use filtering utility to select a subset of orbitals according to one or several criteria . Orbitals in luscus are shown as isosurface of wavefuction value [luscus can display electron density of a molecule as an isosurface in the same manner as orbitals. There is a possibility of displaying other physical quantities that are spatially distributed like orbitals and electron density.One of the most important aspect of s nature  or assigs nature . Therefoon value ,21 in thOrbitals and electron densities are represented as surfaces that engulf molecules. These surfaces can be used for displaying electrostatic potential, by colouring these surfaces according to the value of electrostatic potential. This functionality is usually used with the display of electron density surface since the display of electron density usually resembles on the molecule surface and that way a distribution of electrostatic potential can be visualised across the entire molecule.Luscus can also combine several orbital files and perform simple arithmetic operations with them. This feature is very useful for construction of spin-density or for displaying of electronic transition or charge transfer.Structures from several files can be shown in the same orientation and size, since this information can be saved and retrieved upon opening another file.luscus, based on recently published or on-going research in our group.In this section we give some examples of scientific visualisation done by Luscus is able to use symmetry operations in construction of symmetric molecules, which we will demonstrate by building Ar’-Cr-Cr-Ar’ complex, which was studied at [udied at . This coThe construction of the complex is started with the planar fragment that contains Cr, N, C and H atoms, Figure Molecular clusters or periodic systems require a special attention. The GUI should be able to handle translation symmetry and have capability to highlight certain structural elements. In the following example we will construct a fragment of tobermorite structure, which was used as initial structure in modelling calcium silicate (C-S-H) nanoparticles . C-S-H n4 tetrahedra, Figure The initial structural fragment includes two connected SiO The shape of molecular orbitals and electronic density is essential for understanding chemical boning in molecules.Bi-natural orbitals, which are obtained for a pair of wave functions by a singular value decomposition of a reduced transition density matrix were recently proposed . These oThe selection of active space in multiconfigurational calculations is most difficult and hardly automatised procedure . Visual π-type atomic orbitals of the carbon atoms. However, these orbitals, especially virtual ones, might have one-electron energies (obtained in HF or DFT), which are far away from the HOMO-LUMO gap. Visualisation done by luscus allows to spot all six π−type orbitals  directly.For durene  molecule, the obvious choice of small basis set will span the six SiO force field, by electron equilibration method for each atom in the model. The electrostatic potential is calculated from this point charges and projected onto the crystalline surface.Electrostatic potential is demonstrated on the example of calcium-silicate-hydrate (C-S-H) platelet. C-S-H is a phase that forms during the crystallisation of Portland cement and is responsible for hardening of concrete and thus for its mechanical properties. It crystallises in form of small crystallises, 30–60 nm in diameter and 5–10 nm in height ,28. InteSimulation of liquids requires statistical mechanical approach. The simulation of water droplet Figure  has beenLuscus is a new graphical user interface program, which works as a native counterpart to computational code MOLCAS, but in the same time can be easily connected to other computational codes using external plug-ins. The code is fully portable to various operating systems, and it depends only on a minimal set of external libraries. The main purpose of luscus is to provide state of the art support for advanced computations in quantum chemistry.Project name: luscusProject home page:http://sourceforge.net/projects/luscus/Operating system(s): Linux, Windows, Mac OSProgramming language: COther requirements: gtk+-2.0 or gtk+-3.0, OpenGLLicense: Academic free licenseAny restrictions to use by non-academics: NO


Pencil core granuloma is characterized by a delayed foreign-body reaction against retained fragments of pencil lead. Previous case reports presented pencil core granuloma resemblingmalignant melanoma, haemangioma, or soft tissue sarcoma. We present a case of pencil core granuloma arising from the palm 25 years after the initial injury. The patient presented a bluish nodulethat had been present over 25 years before. The nodule initially measured 5 mm in diameter. However, five years before presentation, it suddenly enlarged to the size of 30 mm during six months.Computed tomography (CT) of the lesion revealed a linear radiopaque structure of 8 mm long with a mass on its distal end. Surgical resection revealed a bluish muddy mass and pencil lead.Histological examination revealed degenerative tissue with calcification surrounded by massive amounts of black granular material in the middle and lower dermis. Pencil core granuloma is characterized by a delayed foreign-body reaction against retained fragments of pencil lead. Previous case reports presented pencil core granuloma resembling malignant melanoma, haemangioma, or soft tissue sarcoma. We present a case of pencil core granuloma arising from the palm 25 years after the initial injury. The granuloma contained a pencil lead of 8 mm long without obvious breakdown.A 67-year-old woman was referred to our department for evaluation of a bluish nodule on the palm of her right hand , arrow. Pencil core granuloma is characterized by a delayed foreign-body reaction against retained fragments of pencil lead. In our case, the patient reported that she had stuck her hand with a pencil 25 years before and that a bluish nodule had been present since then. Five years ago, however, it suddenly started to enlarge to the size of 30 mm over six months and appeared similar to a nodular type of MM. Despite the past history that she had stuck her hand with a pencil, the lesion could not be distinguished from MM because MM may arise from various kinds of injuries. In our case, CT was useful since it showed a clear shape of the pencil lead .Histopathological study of our case revealed a remarkable tissue necrosis and disintegration of pencil lead with scanty infiltration of giant cells or lymphocytes. However, some examinations reported that many giant cells and epithelioid cells were observed in pencil core granuloma , 3. Hata


Current approaches to protect biodiversity by establishing protected areas usually gloss over water pollution as a threat. Our objective was to determine the longitudinal and seasonal distribution of perfluoroalkyl acids (PFAAs) in water column and sediments from a wastewater dominated stream that enters preservation areas. Water samples were collected along the longitudinal section  of the stream during the dry and wet seasons. Sediments were collected from three sites along the stream from three depths. Water and sediments were analyzed for PFAAs using high performance liquid chromatography-tandem mass spectrometry. Eleven PFAAs with 5 to 14 carbon atoms were detected in the water column at all sampling points, with a minor reduction at the last point suggesting a dilution effect. The most detected PFAAs was PFOS, followed by perfluorooctanoic acid (PFOA), and perfluorohexanoic acid (PFHxA). Seasonal differences in PFAAs concentrations suggested contribution of stormwater runoff during the wet season. All analyzed PFAAs in sediments were under the limit of quantification, likely due to the high proportion of sand and low organic matter. However, high concentrations of PFAAs were detected in the water column inside the protected areas, which includes PFOS in concentrations considered not safe for avian wildlife. Water samples appear to be more relevant than sediments to determine PFAAs micro-pollution in water bodies with sandy sediments. Inclusion of a management plans on micro-pollution research, monitoring, and mitigation is recommended for protected areas. Ecological degradation is consistently observed in urban streams. Stressors such as a combination of sanitary sewer overflows and effluents from wastewater treatment plants (WWTPs) are listed as main causes of urban streams impairment . HistoriVarious sources of the highly persistent, bioaccumulative and toxic PFAAs in the aquatic systems include WWTPs, leachate from landfill, and stormwater runoff from streets –8. WWTPsd)  octanoic acid) and perfluoroalkyl sulfonate  were used as internal standards (IS). A 40 ng/L of MPFOA was added to each sample immediately before SPE. The Oasis® HLB 6 cm3 cartridges  with 200 mg sorbent per cartridge (30 μm particle size) were used for the SPE of the water samples.Eleven PFAAs were analyzed using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC/ESI-MS/MS) . In brieThe conditioning of the cartridge was performed with 15 mL of methanol followed by 18 mL of reagent water, without allowing the water to drop below the top edge of the packing. Polypropylene tubing  was used to transfer the water from bottles to cartridges. The vacuum was adjusted in the manifold to allow approximately two drops of water per second. After the entire sample was passed, two 5 ml of reagent water was used to rinse sample bottles and passed through the transfer tubes. The elution of cartridge was performed using 4 ml of methanol added to the bottles and pulled through the transfer tubes; this was repeated two times for each sample. The extract was concentrated to dryness with nitrogen gas in a heated water bath (60°C). The recovery percentage of PFAAs from water samples ranged from 67 to 127% , which is within the accepted extraction efficiency (between 50 to 150% of recovery) when using labeled PFAAs internal standards , 33.Isotope dilution was used to determine PFAAs in water samples. After extraction and drying of water samples, samples were then solubilized in 1 mL of 96:4% (v/v) methanol: water containing 40 ng/mL of MPFOS and injected into the instrument for analysis. The analysis of PFAAs in water samples was performed using an Agilent 1100 series liquid chromatograph  coupled to a 4000 QTRAP mass spectrometer . A C18 Vydac column  from Grace Davison Discovery Science  was used. A Luna C18 column  was inserted between the pump and the injector to eliminate any background flourochemicals from poly (tetrafluoroethylene) instrument components.A standard curve was prepared from 0 to 80 ng/mL of PFAAs; PFOS and PFOA remained constant at 40 ng/mL at all points of the curve. A 5 μL of each standard and sample was injected onto the column and PFAAs were separated using 2 mM ammonium acetate solution as solvent A, and methanol as solvent B at a flow rate of 300 nL/min. The initial condition was set at 40% of solvent B and held for 2 min, followed by a gradient from 40% to 80% of solvent B in 16 min, and held for 2 min. Solvent B was increased to 100% in 1 min and held for another 2 min to ensure that all compounds would elute. Finally solvent B was dropped to 40% in 1 min and held for 7 min to allow the reconditioning of the column for the next injection. Two replicates were injected per sampling point and after each sample at least two blanks were run to eliminate carry over between samples. The column elution was directly sprayed into the mass spectrometer using a turbo V ion spray interface operated in negative mode. The instrument parameters were set as follows: desolvation temperature 300°C, desolvation (curtain) gas 20 arbitrary units (AU), ion spray voltage -4500 V, nebulizer gas 1 and 2 were set at 20 AU respectively, CAD  was set high, and dwell time was 40 msec. Mass spectrometry data were acquired in multiple reaction monitoring (MRM) mode. All instrument parameters for PFAAs standards were optimized and at least two MRM transitions per compound were used whenever was possible .Quantitation of samples was performed in Analyst software (v1.5). The standard curve and samples were normalized using MPFOS as internal standard. Concentrations of samples were obtained by interpolating the normalized area ratios against the standard curve. The recovery rates were calculated by measuring the amount of added internal standard (MPFOS) after extraction.A stainless steel corer was used to obtain the sediment samples from the center of the stream at three sites  and metals .Sediments were analyzed for pH (EPA 150.1), electrical conductivity (EPA 120.1), texture , chloride (EPA 325.2), nitrogen forms   for isotope dilution quantitation. The supernatant passing the cartridge was evaporated to ~1.0 mL (45°C) and prepared in 75:25 methanol: 2mM ammonium acetate in DI water. Standard curves were prepared from extracted standards (no blank matrix) and ranged from 0.1 to 50 ng/g sediment. Sediment extracts were analyzed using a Waters Acquity™ ultra performance liquid chromatograph interfaced with a Waters Quattro Premier XE triple quadrupole mass spectrometer (UPLC-MS/MS) . Samples were injected onto an Acquity UPLC® BEH C18 column . Analytes were gradient separated with a mobile phase made up of 2 mM ammonium acetate aqueous solution with 5% methanol (solvent A) and 2 mM ammonium acetate in methanol (solvent B) over a 12 min gradient. A PFAAs isolator column  was installed between the mixing chamber and injector to eliminate contamination resulting from buildup of PFAAs from the mobile phase on the head of the LC column during column equilibration. In doing so, systemic PFAAs contamination is chromatographically separated from analytical PFAAs. Electrospray negative ionization was used in the mass spectrometer source. The capillary voltage was set at negative 0.4 kV. Cone gas and desolvation gas flows were 0 and 1200 L/h, respectively. The source temperature was 150°C and the desolvation temperature was 350°C. Transitions for all ions were observed using MRM and analyte-specific mass spectrometer parameters were optimized for each compound. The recovery of PFAAs in the sediments ranged from 59 to 131% , which was within the accepted extraction efficiency for sediments ),oc) between 2 to 3 ).Considering the current biodiversity crisis particularly in freshwater ecosystems , the knoPFAAs were detected in the water column along all stream sampling sites with a minor reduction in concentration in the sinkhole point, likely due to the dilution. The most detected PFAAs were PFOS>PFOA>PFHxA>PFHpA>PFDA>PFNA. Minor seasonal differences in PFAAs concentrations were found. Among all PFAAs measured, PFOS was the most prevalent accounting for 40–50%. The PFHpA to PFOA ratio at all sites was <1, suggesting that wastewater and urban stormwater runoff were the major sources of PFAAs. Two points downstream of the restoration project showed higher concentrations of PFOS (156 and 225 ng/L) and PFOA (64 and 80 ng/L), but further research is needed to determine the cause of this phenomenon. Despite the constant occurrence of PFAAs in water samples, the concentration of PFAAs determined in the sediments was under the limit of quantification. We demonstrated that relatively toxic micro-pollutants such as PFAAs were consistently present throughout the year inside two protected areas. Overall, this system receives relatively high amounts of PFAAs compared to global concentrations and cities with similar size. As concentrations of some PFAAs found in this study such as PFOS (224 ng/L) are near levels considered dangerous for aquatic biota  or overS1 Appendix(DOCX)Click here for additional data file.S1 Table(DOCX)Click here for additional data file.