Surface-enhanced Raman scattering (SERS) is a surface-sensitive vibrational spectroscopy that allows Raman spectroscopy on a single molecular scale. Here, we present a review of SERS from molecular junctions, in which a single molecule or molecules are made to have contact from the top to the bottom of metal surfaces. The molecular junctions are nice platforms for SERS as well as transport measurement. Electronic characterization based on the transport measurements of molecular junctions has been extensively studied for the development of miniaturized electronic devices. Simultaneous SERS and transport measurement of the molecular junctions allow both structural  and electronic information on the single molecule scale. The improvement of SERS measurement on molecular junctions open the door toward new nanoscience and nanotechnology in molecular electronics. Aviram et al. first proposed theoretically that electrical rectification was possible with a molecular junction where a donor π system is bound to an acceptor π system via a σ bonded tunneling bridge [junction . At presjunction ,9,10. Sojunction . The QT G0 (G0 = 2 e2/h), 0.01 G0, 4 × 10−4G0) were reported as conductance of a benzenedithiol (BDT) single-molecular junction [G0, 0.040 G0, and 0.004 G0 for bridge, hollow, atop site, respectively [Although various functionalities have been reported for molecular junctions, molecular devices are still far away from practical application, due to large variability of the device performance. For example, several different values  have been employed for numerous molecular junctions and were established as standard methods to identify the molecular junctions [Vibrational spectroscopy is the most straightforward method to determine the atomic and electronic structure of the molecular junction because it provides a molecular fingerprint that can be used to identify the bridging molecule and molecular adsorption site. In 2002, point-contact spectroscopy (PCS) was first exercised to the hydrogen single-molecular junction . PCS obsunctions ,17,18. H15 in the metal nanogap, which is sufficient to study Raman scattering of a single molecule [Optical spectroscopic techniques, such as IR and Raman spectroscopy, are promising for vibration spectroscopy of the molecular junctions at room temperature. However, it seems difficult to use optical spectroscopes to observe the molecular junction. First, it is not easy to focus light to single-molecule size; second, the signal from a single or few molecules is too weak to detect. Fortunately, surface-enhanced Raman scattering (SERS) can overcome these difficulties thanks to the enhanced field formed between metal electrodes ,23,24,25molecule ,27,28,29−1 and 1568 cm−1, which were assigned to a ring breathing mode (ν1) and C=C stretching mode (ν8a) of the BDT molecule, respectively. Other peaks were also assigned to the vibrational modes of the BDT molecule, which clearly showed the existence of the BDT molecules in the gap between the metal electrodes. The authors studied the dependence of SERS intensity as a function of the gap width. The gap width was evaluated by measuring the tunneling current across the gap. In 2006, the first SERS study of the molecular junction was reported by Tian et al. . The BDT−1  in SERS, which confirmed that the BPY molecule bridged Au electrodes. The first SERS of the single-molecular junction was reported by Liu et al. in 2011 . They me−1 peak in the same region shown in −1 (a1 symmetry mode). The SERS signal was only observed at the nanogap. Stable molecular junction could be fabricated with the fixed electrode on the flat substrate. The fixed electrodes could be prepared using electromigration (EM) technique . The EM Using a highly stable molecular junction with fixed electrodes, the temperatures of the charge-transporting molecular junctions were investigated by Ward et al. and Ioffe et al. ,36. TheyS) ratio ,36. Hereectively . Figure G0. Previous research revealed that the conductance of the BPY single-molecular junction was 10−2G0 [Raman shift provides us the information about the atomic structure of the molecular junction. Konishi et al. observed the structural change of the BPY single-molecular junction as a change in the SERS spectra . First,  10−2G0 , indicat−1 , and finally the molecular bridges the electrodes with its molecular long axis parallel to the junction axis.Typically, two types of SERS spectra were observed for the BPY single-molecular junction a. The ba1 top of a was ass−1 in the single-molecular junction regime. The wavenumber of the ring breathing-mode increased (decreased) when the conductance decreased (increased). The observed anticorrelation between wavenumber and electric conductance could be explained based on the metal—molecule interaction. When a molecule adsorbs on the metal surface, the highest occupied molecular orbital (HOMO) of BPY hybridizes with the metal unoccupied states, and the lowest unoccupied molecular orbital (LUMO) hybridizes with the metal occupied states. These two interactions lead to the strong molecule—metal bond. Through these interactions, electrons are removed from the HOMO (bonding) and are injected into the LUMO (anti-bonding). Both electron transfers weakens the bonds of molecule itself. The degree of decrease in the molecular bond strength, corresponding to the wavenumber, depends on the strength of the interaction between metal and molecule. An increase in the metal–molecule interaction, thus, leads to a decrease in the energy of the wavenumber of the molecule. Meanwhile, the electric conductance of the single-molecular junction is described as:Γ and Δ are the electric coupling between the metal and molecular orbitals and the energy difference between the metal and molecular orbitals, respectively. The electric conductance increases with the electric coupling, that is, the metal—molecule interaction. The increase in the metal—molecule interaction, thus, causes the increase in the electric conductance of the single-molecular junction, and decrease in the wavenumber, as experimentally observed in As well as the dramatic change in the atomic configuration of the junction, a slight molecular orientation change was detected as a change in the Raman shift and conductance of the BPY single-molecular junction. I—V) response provides much more information than conductance . Assuming that electron transport through a single channel, I—V response is represented asε0 is the energy of the conduction orbital [ε0 and Γ, are sensitive to the metal—molecule interface structure of the single-molecular junction. By fitting the I–V response to Equation (3), ε0 and Γ can be obtained. I–V responses for BDT single-molecular junctions. Three statistically high-probable nonlinear curves were clearly observed . The distribution of strength Γ also indicates probable three Γ’s in the Γ histogram  rI—V responses. Orange counts in the Γ histogram (Γ. Is) and Γ on a log—log plot. The observed distribution clearly corresponded to a power law relationship, Is ∝ αΓ. This is the first in-situ study of the correlation between the optical and electronic properties in single-molecular junctions [Then, the SERS of the BDT single-molecular junction is discussed based on the results obtained by istogram b correspunctions .Γ. The theoretical calculation based on a single-level Anderson model reproduced the power law relationship. As for the site selectivity, electronic coupling was small for the hollow and atop, and thus, the SERS intensity corresponding to these sites were under the detection limit (SERS inactive). Only high coupling state (H) is visible, which causes site selectivity.The site selectivity and power law relationship were explained by the SERS enhancement mechanism d. The SE60 molecular junctions using the fixed electrode, which were fabricated using EM technique [60 molecular junction. The sharp peak at 520 cm−1 is from the underlying Si substrate, and the peaks between 1000 cm−1 and 1600 cm−1 are from vibrational modes of C60 in the junction. 60 molecular junction as a function of the bias voltages in the bias regime from –0.6 to 0.6 V. Many of the vibrational modes shifted toward low energies when the bias voltage increased. This bias-driven shift is apparent as a curvature of the spectral features  can be injected to the closer lying LUMO and the addition of an electron to the antibonding LUMO softens intramolecular bonds. In the above discussion, we assume that the effect of laser irradiation and bias voltage application on the molecular junction is negligibly small. Although the bias voltage-induced heating was observed for OPV3 molecular junction , it is sechnique . Figure features b. The bi−1 (ν8a) changed to double peaks above 100 mV. When the bias voltage was reversed, the peak splitting disappeared, indicating that the peak splitting relates with the bias voltage. The BPY molecule consists of two pyridine rings. The theoretical calculation revealed that the increase in the bias voltage lowers the Fermi level and increases the density of electric charge on the Au tip. This led to an increase in the strength of the chemical bond between the Au tip and the pyridine ring in contact with it. The peak split could be understood in terms of the different bonding interactions between the Au tip and BPY and between BPY and the Au.The shift of the SERS peaks was observed for the BPY single-molecular junction fabricated with the FM-STM . Figure −3G0 without laser illumination. Under the irradiation of light, a new high conductance peak appeared in the conductance histogram at 3.7 × 10−3G0 in addition to the characteristic low conductance peak at 1.9 × 10−3G0. The low conductance peak (1.9 × 10−3G0) did not entirely shift to a high conductance value (3.7 × 10−3G0) and the both low and high conductance peaks were observed under the light illumination. The authors explained this observation in the following way. In each measurement of a conductance trace, local hot spots can be formed on the surface of Au electrodes where the localized surface plasmon is excited. The formation of local hot spot is sensitive to local roughness of the surface, and the propagation length (Lp) of localized surface plasmon is about a few 10 nm. The localized plasmon affects the conductance of a single-molecular junction only if the distance between the molecule in the junction and hot spot is smaller than Lp. Because this is not necessarily in the case of all conductance measurements, only a fraction of the measurements was affected by the localized surface plasmon. They explained the increase in conductance of the DAF single-molecular junction by taking the plasmon field as an oscillating potential Vω at the plasmon frequency ω across the junction. The calculated transmission probability of the DAF single-molecular junction was dominated by HOMO  in the energy range of EF − ħω < E < EF + ħω. The magnitude of gate voltage (Vω) was evaluated to be 0.169 V.As well as the bias voltage, the light irradiation can affect the electric conductance through the single-molecular junction. Vadai et al. reported the plasmon-induced conductance enhancement in the single-molecular junction . They faI—V response and SERS can clarify the atomic configuration at the molecule—metal interface. The correlated SERS measurements show selectivity towards one of the adsorption sites. Site-sensitivity represents a crucial step toward the reliable integration of millions of molecular components into a working device. The development of the new measurement technique open the door to new science. The further development of the SERS measurement technique should reveal interesting phenomena and useful insight in nanosciece and nanotechnology.In conclusion, we have reviewed the SERS studies of the molecular junction. The molecular junctions have been envisioned as components for miniaturized electronic circuits. The SERS is one of the promising tools to characterize the molecular devices during device operation at room temperature. In SERS measurement of the molecular junction, simultaneous SERS and electrical measurement are crucial. The complementary information is obtained by SERS and electrical measurements, which are essential to fully characterize the molecular junction. The simultaneous conductance and SERS measurement clarify the bridging of target molecule between metal electrodes, and effective temperature, dynamical motion of molecule in the gap, and so on. The simultaneous


Kaposi sarcoma (KS), a vascular tumor caused by infection with human herpesvirus 8 (HHV8), is a systemic disease that can present with cutaneous lesions with or without visceral involvement. Very few cases of KS, most of which were associated with AIDS, have been reported in the adrenal gland. Anaplastic transformation of KS is a rare clinical presentation known as an aggressive disease with local recurrence and metastatic potential. We report here a 47-year-old HIV negative male presented with extra-adrenal symptoms and had an incidentally detected anaplastic adrenal KS exhibited aggressive clinical course. To the best of our knowledge, this is the first case of anaplastic primary adrenal KS without mucocutaneous involvement but subsequently developed other side adrenal metastases in an HIV negative patient. Kaposi sarcoma (KS) is a rare low-grade malignant vascular neoplasm caused by human herpesvirus 8 (HHV8) and often occurs in the setting of human immunodeficiency virus (HIV) infection . KS is aAnaplastic KS, which is defined histologically as a tumor with greater cytologic atypia and high mitotic rate, is accepted as a disease with a more locally aggressive behaviour and metastatic potential, but its exact incidence is indeterminate in the literature , 7.Herein, we report a case of anaplastic primary adrenal KS without mucocutaneous involvement which is incidentally diagnosed in an HIV negative patient and exhibited aggressive clinical course with a metastatic tumor detected at the other adrenal gland seven months after the initial diagnosis.A 47-year-old male applied to a pulmonologist with complaint of cough. Thorax computed tomography was performed and 8 × 6 × 3 cm mass was incidentally detected at left adrenal gland on radiological sections. Then, the patient was evaluated in terms of hormonal activity of the mass by endocrinologist with suspicion of pheochromocytoma, Cushing syndrome, or hyperaldosteronism but the results were negative for each. Subsequently, a dynamic magnetic resonance imaging of left adrenal gland was performed and T1-weighted enhanced images revealed diffuse and heterogeneous enhancement of lesion . These rKS, an unusual tumor described more than 100 years ago, presents in various clinical forms including classic (sporadic), endemic (African), iatrogenic (transplantation-associated), and epidemic (AIDS-related) KS , 9. DespKS has been first described in five cases principally affecting the skin of the lower extremities of elderly men by Kaposi in 1872 . KS reprIn the current literature, there have been few numbers of case reports of adrenal KS most of which were described in patients with AIDS –3. In poRegardless of the clinical subgroup, the histological appearances of KS are similar , 7, 8. TAn anaplastic variant of KS is mainly reported in African cases some years ago and only small series on anaplastic transformation of classic KS has been encountered , 9. AnapDemonstration of HHV8 in lesions of KS by in situ hybridisation (ISH) and recently immunohistochemical methods using a monoclonal antibody against the latency associated nuclear antigen-1 (LATA-1) of HHV8, which can be used in paraffin-embedded tissues, is an invaluable tool in the histologic diagnosis of KS, as this marker is consistently positive in all clinical variants of the disease. Furthermore, it is helpful in differentiating KS from other vascular proliferations which are only exceptionally positive for HHV8 , 8.The differential diagnosis of KS includes many benign and malignant entities depending on its location. KS located at the skin must be distinguished from hemangiomas, lymphangiomas, and their variants, as well as angiosarcoma –9. In ouIn conclusion, we report a 47-year-old man with a left adrenal anaplastic KS demonstrating an aggressive clinical course with a metastatic tumor detected at the other adrenal gland. To the best of our knowledge, this is the first case of anaplastic primary adrenal KS without mucocutaneous involvement in an HIV negative patient. Although extremely rare, KS must be kept in mind in differential diagnosis of adrenal lesions exhibiting KS-like features histologically. Immunohistochemical stains including HHV8 may be helpful in differential diagnosis and establishing accurate diagnosis.


For this purpose, electrospun nanofibers of polys (PHAs) and poly(lactide)s (PLAs) were subjected to degradation tests in vitro and in vivo. In this review, characterization and biocompatibility of nanofibers derived from PHAs and PLAs are described. In particular, the effects of the crystalline structure of poly[(R)-3-hydroxybutyrate], stereocomplex structure of PLA, and monomer composition of PHA on the degradation behaviors are described in detail. These studies show the potential of biodegradable polyester nanofibers as scaffold material, for which suitable degradation rate and regulated interaction with surrounding tissues are required.Biodegradable nanofibers are expected to be promising scaffold materials for biomedical engineering, however, biomedical applications require control of the degradation behavior and tissue response of nanofiber scaffolds  In the field of medical sciences, tissue engineering has been extensively studied to overcome the problems of conventional methods such as organ transplantation and usage of artificial organs . In tissConventionally, collagens and gelatins extracted from animals have been used to produce scaffolds. However, these native collagens contain considerable amount of endotoxins and other peptides that can stimulate tissue reactions in the human body. Therefore, the removal of these contaminants is crucial for medical applications. Furthermore, the usage of collagens from cows is strictly limited for fear of spreading Bovine Spongiform Encephalopathy (BSE) as has been known to occur with collagens extracted from some of the infected tissues such as bone marrow and eyeballs. Hence, the development of scaffold material alternatives to collagens and gelatins has been attempted .in vivo or in vitro.Some polymeric materials, both from natural and synthetic origin, degrade under physiological conditions. For example, poly(glycolic) acid has been utilized in bioabsorptive sutures without the need for removal after healing of wounds. Such biomaterials require a suitable degree of biodegradability and biocompatibility depending on their purposes. In order to regulate these properties, polymeric biomaterials with diverse monomeric compositions, polymeric mixture ratios, or morphologies has been prepared and tested for their biodegradation behaviors R)-3-hydroxybutyrate] [P(3HB)] by Lemoigne in 1920s [R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate] [P(3HB-co-3HV)], poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] [P(3HB-co-3HH)], poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate] [P(3HB-co-4HB)], and poly(4-hydroxybutyrate) [P(4HB)] have been found or developed by controlling the cultivation conditions of microorganisms  films [The formation of β-form structure was first reported by Orts V] films . SubsequV] films , cold-stV] films , cold-drV] films ,37, and V] films . From thV] films . BecauseIt is known that P(3HB) materials with β-form structure has a higher mechanical strength, elasticity and biodegradability than those with only α-form structure ,36,37,38co-5mol%-3HH) (520 nm) > P(3HB-co-97mol%-4HB) (220 nm) > P(3HB-co-7mol%-4HB) (190 nm). It has been reported that the width increases proportionally with the molecular weight of the polymer , and 18.1° that are assigned to α-form homocrystal of PLA [θ = 12.0° [assigned to (110)], 20.8°, and 24.1° that are assigned only to the stereocomplex crystal of PLA.  to poly[(R)-3-hydroxybutyrate-co-97mol% 4-hydroxybutyrate] lead to contrasting tissue responses. The tissue responses were well correlated with the degradability of each polymer scaffolds. Furthermore, PHA nanofiber scaffolds with different monomer compositions showed variant mechanical properties, from flexible poly(3HB-co-97mol% 4HB) to rigid P(3HB) and P(3HB-co-5mol%-3HH). Such variety in the mechanical properties and degradability may facilitate the application of the PHA nanofibers for regeneration of organs or tissues with different mechanical properties.We have shown in this review that the degradation behavior of PHAs position . Nanofibin vivo with the change in the bulk size of each nanofiber mats. The changes in bulk size of the nanofibers were further correlated to the changes in the microscopic morphology, crystallinity, and molecular weight. All these factors give evidence that the stereocomplexed PLA nanofibers are more stable and thus provoke lower degree of inflammation in vivo than the PLLA nanofibers.The degradation study using nanofibers of PLLA and stereocomplexed PLA also suggested the correlation of the degree of inflammatory reaction co-5mol%-3HH) nanofiber scaffold with low degradability may be suitable for the regeneration of hard tissues such as tendons or bones, while flexible and readily degradable P(3HB-co-97mol%-4HB) nanofiber may be suitable for the regeneration of soft tissues such as skins and bone marrows. Such versatility in the biodegradability of PLAs and PHAs would expand their potential as biomateirals. [In general, inflammatory reaction is favored in the case where healing occurs in a short period of time. For example, inflammatory reaction stimulates and accelerates the regeneration of some kinds of epithelial tissues. On the other hand, when healing requires a longer time, chronic inflammatory response is not favored. For example, suppression of the inflammatory responses against artificial vessel has significance in the treatment of circulatory organs that requires a period of more than half a year. From this viewpoint, our results show that the stereocomplexed PLA nanofibers are suitable for the purposes where the chronic inflammatory reaction should be avoided, for example, guided nerve regeneration or blood vessel augmentation. On the other hand, conventional PLLA nanofibers may be suitable for the rapidly bioresorbable materials, for example, wound healing patches. Similarly, rigid P(3HB) or P(3HB-teirals. ,55


Based on bubble electrospinning (BE), a modified free surface electrospinning (MFSE) using a cone-shaped air nozzle combined with a solution reservoir made of copper tubes was presented to increase the production of quality nanofibers. In the MFSE process, sodium dodecyl benzene sulfonates (SDBS) were added in the electrospun solution to generate bubbles on a liquid surface. The effects of applied voltage and generated bubbles on the morphology and production of nanofibers were investigated experimentally and theoretically. The theoretical analysis results of the electric field were in good agreement with the experimental data and showed that the quality and production of nanofibers were improved with the increase of applied voltage, and the generated bubbles would decrease the quality and production of nanofibers. Electrospinning has been recognized as a simple and efficient technique for the production of polymer nanofibers. Due to the high surface area, high surface energy, and high surface activity et al., electrospun nanofibers can be used in a wide variety of applications such as nonwoven fabrics , reinforConventional single-needle electrospinning inhibits the application of nanofibers to commercial applications due to its low production, usually at the level of 0.01–0.1 g/h . It is dIn this paper, a modified free surface electrospinning (MFSE) using a cone-shaped air nozzle combined with a solution reservoir made of copper tubes was presented to obtain high throughput fabrication of quality nanofibers based on bubble electrospinning (BE) . The nozSurface-active agents are generally used to decrease the surface tensions of polymer solutions, which significantly affect the generation of bubbles. As a result, the formation and stabilization of bubbles are greatly dependent on the composition and physicochemical properties of the surface-active agents used . PreviouPVA with 1750 ± 50° of polymerization and SDBS were purchased from Sinopharm Chemical Reagent Co., Ltd. . PVA aqueous solutions with the concentration of 7 wt% were prepared by dissolving PVA powder in deionized water. And 0.3 wt% SDBS was dissolved in the PVA solutions. Then, the solutions were stirred at 90 °C for 2 h until it became homogeneous. All chemicals were of analytical grade and used without further purification.The schematic of the MFSE apparatus was represented in Fig. However, the solution reservoir of the BE apparatus was made of polymer tubes. And a thin polymer tube as nozzle was fixed on the center of the reservoir bottom. A slim metal needle, as the positive electrode, went through the nozzle. The nozzle and the needle were inserted through the bottom of the reservoir and connected with the gas pump and the generator, respectively. The metal electrode would lead to lower applied voltage. Compared with the BE, the MFSE could produce nanofibers under a much higher applied voltage which would result in improving the nanofiber throughput.According to Ref. , 29 and The PVA solution was poured into the reservoir, and the liquid surface was higher than the nozzle. Turning on slowly the gas valve, the liquid surface forms a bow around the nozzle due to the high surface tension of the solution. After an electronic field was applied and the voltage was over the threshold voltage, multiple jets initiated at the convex liquid surface, see Fig. Several bubbles, whose diameters varied from 10 to 30 mm, were generated at the free surface of the polymer solution with the addition of SDBS. These bubbles would be broken into very small ones on their surface. When the surface tension of the small bubbles reduced to the critical value which could be overcome by the applied electric field, multiple jets were ejected from the bubbles to the collector, see Fig. The motion of the jets was observed by a high-definition camera at a frame rate of 25,000 frames/s . Diameter and arrangement of electrospun PVA nanofibers were characterized using a scanning electron microscopy . All samples were dried at room temperature and then sputter-coated with gold by an IB-3  for 10 min. The matrix morphology and fibrous diameter characterization were carried out using Image J software . The electric field distributions were calculated by the Maxwell 2D .The morphologies of PVA nanofibers obtained using MFSE and BE were respectively carried out by SEM. SEM images and the according diameter distribution of nanofibers with different applied voltages in MFSE process were shown in Fig. Figures However, the solution reservoir in which a metal electrode fixed was made of polymer tubes in the BE setup. The positive terminal of the power generator was connected to the metal electrode which led to lower applied voltage. Therefore, the production of nanofibers prepared by BE was only 3 g/h .In the MFSE process, the addition of SDBS to PVA solution could effectively decrease the surface tension of the solution and generate bubbles on a liquid surface. Table The mechanical properties, such as tensile strength and elongation-at-break, of PVA nanofiber membranes without and with SDBS were shown in Table Since the electric field is the main driving force to generate jets , the jet11 us/cm, the working distance was 130 mm, the applied voltage was 60 kV, and the diameters of bubbles were 20 and 25 mm, the surface tensions of 7 wt% PVA solutions without and with SDBS were 45 and 33 mN/m, and the electric conductivity of these solutions were 8.8 and 43 us/cm respectively.Figure Figure In this paper, a high-effect free surface electrospinning using a cone-shaped air nozzle combined with a solution reservoir made of copper tubes was successfully developed to obtain high throughput fabrication of quality nanofibers for a long spinning time. The effects of the applied voltage on nanofiber quality and production were systematically investigated, and the results showed the quality and production of nanofibers were improved with the increase of applied voltage. Compared with the BE, the MFSE could produce nanofibers under a much higher applied voltage which would result in decreasing the nanofiber diameter, enhancing the diameter distribution, and improving the nanofiber throughput.In addition, a surface-active agent, SDBS, was added in the electrospun solution to generate bubbles at the free surface of the solution in the MFSE process. The effect of bubbles on the nanofiber morphology and production was experimentally investigated. The results showed that with the increase of spinning time, the MFSE made the diameter distribution of the PVA nanofibers to have little change, and the generated bubbles would decrease the quality and production of nanofibers. Finally, the electric field distributions around the free surface and the bubbles were calculated respectively by the Maxwell 2D, and the simulation results were in good agreement with the experimental results.


Tridacna maxima were characterized over a two-year-period in the lagoon of the high island of Tubuai  and in the semi-closed lagoon of Tatakoto (Tuamotu Archipelago) in French Polynesia. We also recorded temperature, water level, tidal slope, tidal range, and mean wave height in both lagoons. Lower lagoon aperture and exposure to oceanic swells at Tatakoto than at Tubuai was responsible for lower lagoon water renewal, as well as higher variability in temperature and water level at Tatakoto across the studied period. These different environmental conditions had an impact on giant clams. Firstly, spawning events in the lagoon of Tatakoto, detected by gonad maturity indices in June and July 2014, were timed with high oceanic water inflow and a decrease in lagoon water temperature. Secondly, temperature explained differences in shell growth rates between seasons and lagoons, generating different growth curves for the two sites. Thirdly, local mortality rates were also found to likely be related to water renewal patterns. In conclusion, our study suggests that reef aperture and lagoon water renewal rates play an integral role in giant clam life history, with significant differences in rates of shell growth, mortality and fertility found between open versus semi-closed atoll lagoons in coral reef ecosystems.Shell growth, reproduction, and natural mortality of the giant clam  Tridacna maxima and T. squamosa, are widespread throughout the Indo-Pacific and can be found from the Red Sea and southeast Africa in the west to the Central Pacific in the east [T. maxima), where light provides them most of the energy necessary for survival, growth, and reproduction, owing to the ability of their symbiotic zooxanthellae to photosynthesize [Among the 12 species of giant clams , nthesize .T. maxima [Giant clams play various ecological roles in coral reef ecosystems . Their t. maxima .Most species of giant clams were traditionally exploited by local fishers for meat consumption or shell use as common household items . Over thT. maxima , is still found in relatively high densities at various locations throughout the Central Pacific [Tridacna maxima is currently classified as lower risk/conservation dependent  under the IUCN Red List for threatened species. Densities and stocks can vary locally by several orders of magnitude, depending on past and present fishing pressure and fluctuations in environmental drivers [T. maxima’s meat and the related depletion of their stocks throughout their range has highlighted the need for conservation measures designed to address the state of the resource at local levels. Thus, quantifying stocks and their spatial distribution are the first steps necessary to relevant management planning.The small giant clam  Pacific . Tridacn drivers . The incT. maxima stock and individual density estimates of T. maxima were derived for a number of locations and reef types . Densit Tuamotu , 5. At iubstrate , 10. Theubstrate ) and supubstrate , 11).T. maxima densities has also been reported for the enclosed lagoon of Millennium atoll  and their interaction with the environment. When estimated at a specific point in time, stock distribution alone cannot provide an accurate view of population dynamics. Any conclusions drawn from such an assessment may therefore affect the success of long term management. For example, a re-evaluation of stocks at Tatakoto in 2012 highlighted a tenfold decrease in observed densities . Howeveriribati; ). This rT. maxima’s life traits  based on a sampling scheme spatially-structured at a number of scales. At lagoon and regional scale, our study sampled two sites in French Polynesia differing in their location and reef type. At intra-lagoon scale, the sampling scheme was designed according to the abiotic factors previously identified to structure the spatial distribution of densities at both locations [T. maxima life traits at different scales.Besides the monitoring of stocks at regular time intervals, sustainable management also requires a clear understanding of population dynamics and biological processes, as well as their interaction with environmental factors at regional scale , reef scale , and intra-lagoon scale  . Howeverocations . We alsoT. maxima collections for this study were authorized by French Polynesia Ministerial Order no. 2850/MRM.All Our study focused on two sites in French Polynesia: the semi-closed atoll of Tatakoto  located in the Tuamotu Archipelago, 1,200 km East of Tahiti; and the island of Tubuai  located in the Austral Archipelago, 600 km South of Tahiti . Offshor-1), bringing cool, dry weather that may last for several days. Such wind patterns are less common in the Tuamotu. These differences in wind patterns result in stark differences in annual rainfall and sunshine hours at both locations: around 2,000 mm.yr-1 and 2,200 h.yr-1 at Tubuai compared to 1,000 mm.yr-1 and 2,800 h.yr-1 at Tatakoto respectively [The two sites are also exposed to different wind regimes : northeaectively , 19.2) is open as it is permanently connected to oceanic waters through a large reef pass in the northern part of the lagoon, and a small reef pass at the southwest end of the lagoon (T. maxima in the context of this study). The atoll rim of Tatakoto is closed in its northern part, but the lagoon (11.46 km2) is connected to the ocean by way of several shallow channels that bissect the southern part of its rim (T. maxima were recorded in 2004 at the eastern extremity of the lagoon (up to 544 ind.m-2) leading to this area’s classification as a no take area (NTA) that same year [The two study sites are also representative of two contrasting reef aperture configurations . The lae lagoon . All ree its rim . Tatakotame year . Our stuTo characterize the physical environment of Tatakoto’s and Tubuai’s lagoons, we deployed temperature and pressure sensors at a number of locations at both sites. The exact positions, measurement types, and depths at which the sensors were deployed are summarized in At Tatakoto, one sensor (RBRduo n°3) at station 15 recorded temperature every 30 minutes, and pressure in bursts of 512 measurements every 30 minutes from November 2012 to October 2014. Pressure measurements provided (i) a proxy for water levels inside the lagoon, (ii) tidal slope and tidal range, and (iii) mean wave height (H). Two further temperature sensors (SBE56 n°1 and n°2) and one pressure sensor (DR1050 n°4) were placed at opposite ends of the lagoon to characterize the wave exposure and thermal variations of these shallow areas. A greater sampling effort was allocated to temperature measurements at Tatakoto, as previous research has suggested this factor as critical to structuring the giant clam population in the atoll’s lagoon [T. maxima densities in this lagoon [At Tubuai, one sensor TWR2050 n°3) at station 7 recorded temperature every 30 minutes and pressure in bursts of 512 measurements every 30 minutes from April 2013 to December 2014. Four further pressure sensors  were also deployed at various locations to compare wave exposure between the western reef flat (sensors n°1 and n°5), the southern reef flat (sensor n°4), and patch reefs located in the eastern part of the lagoon (sensor n°2). The absolute values of the difference between two pressure measurements taken at one-minute interval (δP) were used as a proxy of wave exposure. Sampling at Tubuai focused on pressure (instead of temperature) as wave exposure has previously been identified as the main factor structuring 0 n°3 at We estimated growth and natural mortality of giant clams through regular monitoring of tagged individuals.At Tatakoto, where individuals occur in high density aggregations, we used a tagging technique commonly referred to in the literature , 26, 18:At Tubuai, the lower densities of giant clams allowed us to implement a method that is not stressful for the animals. Individuals were identified by their colours and their position along permanently established transects. Overall, 424 individuals were virtually tagged in April 2013. We checked whether individuals were still alive and estimated their shell length (anterior-posterior measurements) to the nearest millimetre using callipers in November 2013, May 2014, and December 2014. No supplementary tagging was needed at Tubuai as the majority of initially tagged clams were relocated in resurveys.Analyses of natural mortality and shell growth were first performed at lagoon-scale  for the entire study period. For considerations at intra-lagoon-scale, we structured the analyses by the same factors that structured sampling . The monitoring field visits allowed us to define four time periods at Tatakoto and three at Tubuai, each including either the coldest time of the year  or the warmest .G) between field visits were calculated using the following equation:Lt is the shell length  at time t and Δt denotes the time interval between two measurements (in days). The instantaneous natural mortality rate (M) was calculated using Nt and Nt+1 are the number of survivors between the start and the end of the time period considered. We assumed for giant clams that “disappeared” between two sampling events to be dead in our analyses , from the western part of the lagoon. The sampling location was chosen for practical and logistical reasons. At Tubuai, the monitoring of gonad maturation could not be conducted in as systematic a fashion as at Tatakoto because of operational constraints. Thus, samples were collected opportunistically 5 times over a two year period: August 2013, November 2013, September 2014, December 2014, and August 2015.Wbiomass , and the gonad weight Wgonad, to calculate the “Gonado-Somatic Index” (GSI)  .versus male tissues  and the proportion of male tissues harbouring spermatozoids (SPZ) were also calculated using histological treatments and used as proxy of sexual maturity, following the procedure recommended by a recent study [The proportion of female nt study .Tv) from the recorded values of temperature (T) using the following equation:We calculated the mean temperature over the study period  for parameters G) and instantaneous rate of natural mortality (M)—both calculated over the entire study period—were expressed as a linear model of mean shell length (function lm of stats package in R.3.1.0). To allow for comparison of shell growth rates published elsewhere, the estimates of intercept and slope were used to calculate the growth parameter k and the asymptotic length at which growth is zero (L∞) of the Von Bertalanffy growth equation:At the scale of the lagoon, shell growth rate (M) were square-root transformed and expressed as a function of seasons, stations, depth and interactions between these factors on the basis of a linear model. Shell growth rates (G) calculated over each monitoring period were expressed as a function of shell length and sampling-structuring factors  using a linear mixed model (function lme of nlme package in R. 3.1.0.). We could not test for interactions between factors, but a random effect considered the existence of dissimilarities between individuals . For all models, we checked the assumption of homogeneity of variance and normality of residuals graphically using normal quantile-quantile plots and scale-location plots of sqrt. The significance of each parameter was tested using an analysis of variance (anova function in R.3.1.0.).At intra-lagoon scale, instantaneous mortality rates (Tv) estimated at 2.02 ± 0.007 for Tatakoto and 2.01 ± 0.004 for Tubuai. Even though the temperature sensor n°3 at Tatakoto was located slightly deeper than the temperature sensor at Tubuai  at Tatakoto than Tubuai . Seasonat Tubuai , the shot Tubuai ; with a -1 and 0.13 m.h-1 respectively for Tubuai compared to -0.03 m.h-1 and 0.04 m.h-1 for Tatakoto. Analyses highlighted that a 10-day period of low mean wave height (< 1×10−3 m) at Tatakoto (−3 m), and the water level of the lagoon was permanently influenced by tide .The tidal slope was an order of magnitude higher at Tubuai than Tatakoto, with 5% and 95% quantile values at -0.12 m.hTatakoto  was assoTatakoto , a decreTatakoto , and a mTatakoto . At TubuAt intra-lagoon-scale, the three temperature sensors deployed at Tatakoto yielded similar results despite being placed at different locations and depths  showed high variability. However, on average, growth rates (± SD) at lagoon-scale were higher and more variable during the warm season (1.84×10−3 ± 3.21×10−3 cm.d-1 and 2.29×10−3 ± 2.68×10−3 cm.d-1 for Tatakoto and Tubuai respectively) than the cold season (0.83×10−3 ± 2.20×10−3 cm.d-1 and 1.94×10−3 ± 2.15×10−3 cm.d-1 for Tatakoto and Tubuai respectively). The seasonal difference in mean growth was more pronounced at Tatakoto, but remained significant at both sites (p < 0.001 and p < 0.01 for Tatakoto and Tubuai respectively).Results for shell growth rates (2 = 0.44 for Tubuai and R2 = 0.13 for Tatakoto). Means (± SE) for the Von Bertalanffy parameter k was higher at Tubuai (2.7×10−4 ± 1.6×10−5 d-1) than Tatakoto (1.5×10−4 ± 3.9×10−5 d-1), yielding contrasting growth curves (L∞ were comparable at both sites (19.7 and 20.0 cm for Tubuai and Tatakoto respectively).Shell growth rate was found to decline significantly with increasing shell length  was estimated at 0.47 ± 0.07 in December 2013, declining to 0.12 ± 0.02 in June 2014 . This deM) per shell length class and over the entire study period differed markedly between Tatakoto and Tubuai , whereas it decreased significantly with shell length at Tatakoto (p < 0.001). Natural mortality did not show any seasonal trend (warm season versus cold season)  were significantly lower (p < 0.01) at station 15 and station 21 . Both stations are located in close proximity to the narrow and shallow channel in the fringing reef connecting the lagoon with the ocean. At Tubuai, there were no significant differences between stations (p = 0.458), despite lower values in M for patch reefs in the eastern part of the lagoon  because of high individual variability and measurement error. However, findings did suggest slower growth at Tatakoto compared to Tubuai and similar maximum sizes for the two lagoons  and lower theoretical maximum sizes (L∞ = 21.85 for Tatakoto and Fangatau against 24.7 for Tubuai) [The shell growth rate of bivalves is often reported as a function of their shell length or age. For giant clams, the acquisition of energy may influence the relationship between shell growth rate and shell length since the number of zooxanthellae per unit of flesh decreases with age . Our res lagoons . These r Tubuai) . The difGrowth curves reported in the literature usually suggest that old individuals (> 10 years) are characterized by smaller shell length in atoll lagoons compared to other reef systems . The groAt intra-lagoon scale, higher growth rates and higher variability in growth were recorded at Tatakoto for giant clams located in shallow areas, corroborating other studies’ findings . ConsideTo date, very few studies have looked into the reproductive activity of giant clams , 44. In T. maxima’s reproductive activity in enclosed reef systems [In this study, we found a decline in maturity indices in May and June 2014 at Tatakoto, indicative of a mass spawning event over that time period. This spawning event followed a decline in temperature, associated with high mean wave heights and a greater connection between the lagoon and the ocean . We cann systems , 46.Estimates of instantaneous rates of natural mortality were higher at Tatakoto than at Tubuai, particularly for the small shell length classes . It is uT. gigas; [Perkinsus sp. was detected in 2012. This parasite is known to affect juveniles [Factors that may cause elevated natural mortality rates among juvenile invertebrates include: disease, predation, competition, loss of energy, and unfavourable physical and chemical properties of seawater  . At Tatuveniles , but infOctopus cyanea) were regularly observed during field trips, as well as high predation rates on small giant clams by numerous fish (Labridae and Tetraodontidae) and gastropods (Pyramidellidae). The presence of predators and parasites in atoll lagoons may follow cyclical predator-prey relationships, with high abundances possibly the result of previously high giant clam densities [The thin and delicate shells of small giant clams make them more vulnerable to predators . Some auensities . HoweverIntra-specific competition related to density-dependent processes can also negatively influence the natural mortality and shell growth of bivalves . In the versus island). The reef pass and submerged reef flat at Tubuai allow for increased exchange between lagoon and oceanic waters. In this highly open lagoon, water levels are permanently driven by the tide (hoa) that allow for oceanic and lagoon waters to mix during periods of high southerly swell (more common between March and September) and east/southeasterly winds. We found that a 10-day period of low waves inside the lagoon  was associated with a decrease in lagoon water level and an increase in water temperature. At intra-lagoon scale, the lowest mortality rates were recorded at stations 15 and 21, located in close proximity to where the lagoon and ocean connect, while the highest mortality rates were recorded in areas subject to greater variations in temperature and more intense warming. This suggests that high water renewal rates and the associated physico-chemical water characteristics  in these areas increase survival. These results strengthen the idea that a prolonged period of “lagoon closure”  may decrease giant clam survival throughout the lagoon.Finally, the higher mortality rates recorded at Tatakoto compared to those recorded at Tubuai may be the result of contrasting physical characteristics of lagoon waters between the two sites. In this study, we highlighted differences in temperature, wave exposure, tidal slope, and water level variability between both locations, partly due to their distinct reef aperture configuration Click here for additional data file.S1 FigA-2013: April 2013; N-2013: November 2013; S-2014: September 2014; D-2014: December 2014; A-2015: April 2015. SPZ (grey): male maturity index. GSR (red): Gonadal Sex-Ratio. GSI (black): Gonado-Somatic Index.(EPS)Click here for additional data file.S2 FigDashed vertical lines indicate field trip during which the survival of giant clams was checked. The lower panel display values for the instantaneous rate of mortality (M) obtained at the end of each period. The water level line is greyed out before 15/10/2013 as the sensor was placed slightly deeper than usual on its pedestal (20 to 40 cm).(EPS)Click here for additional data file.S3 FigDashed vertical lines indicate field trip during which the survival of giant clams was checked. The lower panel display values for the instantaneous rate of mortality (M) obtained at the end of each period.(EPS)Click here for additional data file.S4 Fig(EPS)Click here for additional data file.


The development of pharmacotherapeutics that reduce relapse to alcohol drinking in patients with alcohol dependence is of considerable research interest. Preclinical data support a role for nucleus accumbens (NAc) κ opioid receptors (KOR) in chronic intermittent ethanol (CIE) exposure-induced increases in ethanol intake. Nalmefene, a high-affinity KOR partial agonist, reduces drinking in at-risk patients and relapse drinking in rodents, potentially due to its effects on NAc KORs. However, the effects of nalmefene on accumbal dopamine transmission and KOR function are poorly understood. We investigated the effects of nalmefene on dopamine transmission and KORs using fast scan cyclic voltammetry in NAc brain slices from male C57BL/6J mice following five weeks of CIE or air exposure. Nalmefene concentration-dependently reduced dopamine release similarly in air and CIE groups, suggesting that dynorphin tone may not be present in brain slices. Further, nalmefene attenuated dopamine uptake rates to a greater extent in brain slices from CIE-exposed mice, suggesting that dopamine transporter-KOR interactions may be fundamentally altered following CIE. Additionally, nalmefene reversed the dopamine-decreasing effects of a maximal concentration of a KOR agonist selectively in brain slices of CIE-exposed mice. It is possible that nalmefene may attenuate withdrawal-induced increases in ethanol consumption by modulation of dopamine transmission through KORs. Chronic alcohol use disorders are an enormous economic and financial burden in the United States . A largeThe dynorphin/Kappa opioid receptor (KOR) system is of particular interest due to its involvement in modulating ethanol drinking behaviors. For example, prodynorphin knockout mice showed lower preference for ethanol and consumed lower amounts of ethanol compared to wild-type mice . FurtherNalmefene  is a pharmacotherapeutic agent approved in the European Union to combat heavy alcohol drinking in at-risk patients   and increased rates of dopamine uptake  compared to air-exposed controls.We maintained BECs at behaviorally and physiologically relevant levels (219.50 ± 39.31 mg/dL), as per [F4,8 = 5.29, p < 0.01), although this effect was greater in CIE exposed animals . No interaction between these factors was detected . When the absolute values of dopamine uptake rates after application of nalmefene were compared across the two groups, there were no differences , which was similar between inhalation groups .To examine the effects of nalmefene on dopamine release and uptake following ethanol vapor and air exposure, increasing concentrations of this compound were bath-applied to accumbal brain slices. A comparison of percent change in dopamine uptake rate showed that nalmefene dose-dependently reduced uptake rates in both groups , while a main effect of inhalation treatment on uptake rates  was detected. Bonferroni post hoc analysis revealed a significant difference between the effects of norBNI on CIE-exposed mice compared to air-exposed controls (p < 0.05).A separate group of brain slices were incubated in norBNI for 60 min to assess the effects of KOR blockade on dopamine transmission. A two-way ANOVA showed no effect of norBNI on dopamine release , which was greater in brain slices from mice exposed to CIE . An interaction between these factors was also detected . Bonferroni post hoc analysis revealed a significant difference between inhalation groups at the 0.1 µM (p < 0.01) and 0.3 µM (p < 0.05) U50,488 concentrations.Representative traces showing the effects of 0.3 µM U50,488 on dopamine release and uptake , as well as an interaction between drug and inhalation treatment . An effect of inhalation treatment alone was not detected . Bonferroni post hoc analysis revealed a significant increase in dopamine release due to nalmefene reversal in the CIE-exposed group compared to the 0.3 µM U50,488 concentration (p < 0.01).As nalmefene is a partial KOR agonist, it competes for the endogenous ligand binding site on the receptor ,20. To dF3,8 = 1.26, p > 0.05) in either inhalation group . Further, a two-way RM ANOVA revealed that nalmefene had no effect on dopamine uptake rates following the maximal (0.3 µM) concentration of U50,488 .As nalmefene reduced dopamine uptake rates to a greater extent in brain slices from CIE-exposed mice compared to air-exposed controls, we examined the effects of a nalmefene challenge on U50,488-induced reductions in dopamine uptake rates. Surprisingly, a two way RM ANOVA revealed no effect of U50,488 on dopamine uptake rates  and delta (DOR) opioid receptors , making  release . Therefo release  and, the release . Since wAlthough the effects of nalmefene on dopamine release were similar between inhalation groups, this compound concentration-dependently reduced dopamine uptake rates more in brain slices from CIE-exposed mice compared to controls. In this instance, it appears as though nalmefene is acting to reduce dopamine release and uptake through KORs. Notably, dopamine transporters have been consistently reported to be functionally upregulated following CIE exposure ,3,4,9. HTo better understand the distinct effects of nalmefene on KOR function between the inhalation groups, a high concentration of nalmefene was applied to brain slices following a maximal concentration of U50,488. As earlier experiments suggested that dynorphin tone is undetectable in brain slices, the addition of U50,488 was necessary to examine any antagonistic effects of nalmefene on KORs. We found that nalmefene reversed the dopamine-decreasing effects of U50,488 in brain slices from CIE-exposed mice, suggesting that nalmefene competed with U50,488 for KOR occupancy. It is possible that this effect is due to CIE-induced receptor upregulation or functional supersensitivity of the kappa opioid system compared to air-exposed animals. In other work, CIE exposure increased levels of KOR binding in seizure-resistant mice  and augmCompounds that alleviate ethanol-induced reductions in dopamine transmission following chronic ethanol exposure, such as those that manipulate KORs, may assuage withdrawal symptoms. Previous work has shown that norBNI blocks withdrawal-induced increases in brain reward thresholds following chronic ethanol  and cocaIntra-cerebroventricular  and intrThe time-course of nalmefene-induced alterations in neurobiology is rapid and beneficial in the therapeutic application of this compound. In fact, ethanol intake in ethanol dependent rats was reduced with lower doses of nalmefene than non-dependent animals , and occMale C57 mice  were used for all experiments. Animals were allowed at least one week of habituation to the housing environment before CIE procedures began. All mice were individually housed and maintained on a 12-h light-dark cycle (lights off at 14:00), with a red-room light illuminated during the animals’ dark cycle. Standard rodent chow and water were available ad libitum, and replaced daily in the CIE exposed group. At 6–8 weeks old, the mice used in the present study are within the range of early adulthood ,49. NotaThis study utilized a CIE exposure protocol previously published . BrieflyTo ensure proper ethanol chamber function and physiologically relevant BECs, a submandibular vein blood draw was performed in ethanol vapor-exposed mice only. Less than 15 µL of blood was collected in BD microtainer tubes lined with lithium heparin . For BEC measurement, standards and samples were prepared with a commercially available alcohol dehydrogenase assay  and carefully pipetted into a 96 well plate. Plate analysis was done with SoftMax Pro Software, version 5 . Mean BECs were 219.50 ± 39.31 mg/dL.FSCV was used to detect CIE-induced changes in dopamine release and uptake, as well as the effects of nalmefene, U50,488, and nor-binaltorphimine (norBNI), a KOR-specific agonist and antagonist, respectively, on dopamine dynamics and kinetics. Briefly, 300-µm-thick coronal brain slices, containing the NAc core were, prepared using a vibrating tissue slicer. Slices were incubated in oxygenated artificial cerebrospinal fluid and heated to 32 °C for approximately 60 min prior to experiment start. A bipolar stimulating electrode  and carbon fiber microelectrode  were placed within 100 µm of each other on the surface of the slice. Dopamine efflux was induced by a single, rectangular, electrical pulse , and detected by applying a triangular waveform every 100 ms to the recording electrode . When baseline collections were stable for three consecutive stimulations, nalmefene , norBNI  and U50,488  were cumulatively added to the bath. Following the maximal concentration of U50,488 (0.3 µM), a challenge concentration of nalmefene (10.0 μM) was added to the bath solution. In a separate set of experiments, a single dose of norBNI (1.0 µM) was applied to brain slices to identify the effects of KOR blockade on dopamine release and uptake measures. Clear current versus time plots were obtained using background current subtraction methods. Electrodes were calibrated immediately after experiments by recording their response (in nA) to a known concentration of dopamine (3.0 μM) using a flow-injection system.Vmax was calculated as the maximal rate of uptake at the dopamine transporter. The apparent affinity of dopamine for the dopamine transporter (apparent Km) remained constant at 160 nM throughout analysis [Representative pre-drug traces of electrically-stimulated dopamine release were individually modeled. Data were collapsed across inhalation groups to obtain baseline dopamine release and uptake measures. Dopamine release was calculated as the amount of electrically-evoked dopamine released per stimulation, and analysis . The effanalysis  was usedt-tests were used to analyze the effects of inhalation exposure on dopamine release and uptake rates. Repeated measures (RM) two-way analysis of variance (ANOVA) was used to determine the effects of increasing concentrations of U50,488 and nalmefene on dopamine release and uptake, with inhalation exposure and drug concentration as factors. Additionally, non-RM two-way ANOVAs, with inhalation exposure and drug concentration as factors, were used to determine the ability of nalmefene to reverse the dopamine-decreasing effects of the 0.3 µM U50,488 concentration, the effects of nalmefene on the maximal rate of uptake following 0.3 µM U50,488, as well as the effects of 1.0 µM norBNI on dopamine release and uptake parameters. When a significant main effect was detected, Bonferroni post hoc analysis was applied.Graphs were created and statistical analyses were applied with GraphPad Prism . Student’s Due to the high rate of recidivism to alcohol use disorders, the need for effective pharmacotherapies for this disorder is high. Modulation of KORs to restore dopamine system function during alcohol withdrawal is of interest therapeutically . Overwhe


Introduction. Kaposi's sarcoma (KS) usually manifests as a cutaneous disease but GI manifestation is often rare. It is associated with human herpes virus-8 (HHV-8) and seen in immunocompromised patients. In the USA, use of highly active antiretroviral therapy (HAART) has drastically reduced incidence of KS in HIV patients. Case Presentation. A 65-year-old male with human immunodeficiency virus (HIV) was admitted to the intensive care unit (ICU) with cardiopulmonary arrest secondary to hyperkalemia of 7.5 meq/L. Following placement of orogastric and endotracheal tube (ETT), a significant amount of blood was noticed in the ETT. Hemoglobin trended down from 9.6 mg/dL to 6.7 mg/dL over five days. Stool guaiac was positive. Esophagogastroduodenoscopy (EGD) was performed and revealed multiple large hypervascularized violaceous submucosal nodular lesions with stigmata of bleeding seen on the soft palate and pharynx and within the cricopharyngeal area close to the vocal cords. Biopsy of the soft palate lesions showed proliferation of neoplastic spindle shaped cells arranged in bundles with slit-like capillary spaces containing erythrocytes consistent with Kaposi's sarcoma. Biopsy was positive for HHV-8. Colonoscopy was unremarkable. There were no cutaneous manifestations of the disease. Conclusion. GI involvement of Kaposi's sarcoma must be considered in immunocompromised patients and can be confirmed by endoscopic methods. Kaposi's sarcoma (KS) usually manifests as slowly progressive multiple reddish purpose cutaneous or mucosal nodules associated with human herpesvirus-8 infection (HHV-8) and seen in immunocompromised patients with some variants –3. OrophIn the US, the widespread use of highly active antiretroviral therapy (HAART) has profoundly decreased the incidence of KS in HIV-infected patients. On the other hand, the innovation of transplantation and the implication of new generations of immunosuppressants have contributed to the rise of new incidental spikes of KS.A 65-year-old Caucasian gentleman with a history of acquired immunodeficiency syndrome (AIDS) on HAART and chronic obstructive pulmonary disease (COPD) was admitted to the intensive care unit (ICU) after having cardiopulmonary arrest secondary to hyperkalemia with a value of 7.5 meq/L (reference range: 3.4–5.2 meq/L). Following the placement of the orogastric tube (OG) and endotracheal tube (ETT), significant amounts of blood were noticed in the ETT. His hemoglobin dropped from 9.6 mg/dL to 6.7 mg/dL over the following five days and his stool was positive for occult blood. He underwent upper GI endoscopy and colonoscopy. Upper endoscopy revealed multiple large hypervascularized violaceous submucosal nodular lesions with stigmata of recent bleeding on the soft palate and pharynx and within the cricopharyngeal area close to the vocal cords. No active bleeding was noted. The examination of the distal esophagus revealed severe ulceration with a small hiatal hernia (see Figures A biopsy from the soft palate lesions showed proliferation of neoplastic spindle shaped cells arranged in bundles with slit-like capillary spaces containing erythrocytes consistent with Kaposi's sarcoma. Biopsy was also positive for HHV-8.Colonoscopy was unremarkable for similar lesions, polyps, or diverticulosis. There were no cutaneous manifestations of the disease. The patient was started on proton pump inhibitors. The bleeding stopped spontaneously without intervention and his hemoglobin stabilized prior to discharge. After his discharge from the hospital, he was scheduled for capsule endoscopy as outpatient to evaluate the small bowel, but unfortunately he expired prior to the exam.The differential diagnosis of upper GI bleeding for immunocompromised patients is wider than regular patients. Neoplasms are the most frequent cause of upper GI bleeding in patients with AIDS . One of Skin lesions are the most common manifestations of KS and are seen in 90% of cases. Other organs in which KS is most frequently involved are lymph nodes, lungs, oropharynx, and the GI tract, particularly the stomach. GI KS may be asymptomatic due to submucosal growth and slow progression of the tumor, or it may express GI bleeding, dysphagia, or location-related pain . During The diagnosis of oropharyngeal and upper GI KS is made via endoscopy. We feel that it is very important for GI endoscopists to be familiar with the endoscopic appearance of KS. In conclusion, immunocompromised patients, including AIDS and transplantation patients, are at risk of developing KS, and at least a few of them might have GI tract involvement. Still routine endoscopic screening for pharyngeal, laryngeal, and GI involvement of KS without apparent symptoms is not recommended, which could be contributed to the fact that the most GI endoscopists are not very familiar with this disease.


The results demonstrated that a static PFF Rosensweig instability with a conical protrusion could be obtained under the magnetic field. The tip of the protrusion emitted an electrospinning jet under the coincident magnetic and electric fields. The needleless electrospinning showed a similar process phenomenon in comparison with conventional electrospinning. The prepared nanofibers were composed of Fe3O4 particles and PVP polymer. The Fe3O4 particles aggregated inside and on the surface of the nanofibers. The nanofibers prepared by needleless electrospinning exhibited similar morphology compared with the conventionally electrospun nanofibers. The nanofibers also exhibited good ferromagnetic and magnetic field responsive properties.Magnetic nanofiber has been widely applied in biomedical fields due to its distinctive size, morphology, and properties. We proposed a novel needleless electrospinning method to prepare magnetic nanofibers from the self-assembling “Taylor cones” of poly(vinyl pyrrolidone) (PVP)/Fe Polymer magnetic composites are an exciting new class of multifunctional materials, where magnetic particles are incorporated into solid polymer matrices . PolymerMany synthetic approaches have been explored to prepare 1D magnetic nanostructures, including template-assisted growth , self-as3O4 ferrofluid (short for PFF) for the needleless electrospinning of the nanofibers. The Rosensweig instability of ferrofluid and needleless electrospinning process under the simultaneous magnetic and electric fields also will be observed. The morphology and magnetic properties of PVP/Fe3O4 nanofibers will be analyzed. We hope the magnetic nanofibers prepared in this work will be applied in biomedical fields, such as hyperthermia therapy and tissue engineering.In this study, we propose a novel fabrication method of needleless electrospinning of the magnetic nanofibers from the self-assembling “Taylor cones” of a ferrofluid under simultaneous magnetic and electric fields. The “Taylor cones” of the ferrofluid were directly self-assembled under the permanent magnets without any extra power. The needleless electrospinning setup is extremely simple and cost-effective. The multiple parallel electromagnetostatic jets can be realized through the application of simultaneous magnetic and electric fields to the electrically-conducting ferrofluid with no needles . MultiplThe interaction between the adjacent droplets can be ignored due to their size and distribution , so we tSelf-assembly is a process in which interacting bodies are autonomously driven into ordered structures by free-energy gradients . The sta3O4 ferrofluid is turned down, resulting in diminution of needless electrospinning, as shown in The needleless electrospinning process of one PFF droplet was captured by a high-speed camera at 2000 fps and analyzed frame by frame, as shown in 3O4 nanofibers are shown in 3O4 particles wrapped on their surface. The inner microstructures of the nanofibers were further investigated by TEM, as shown in 3O4 particles are dispersed both in and on the surface of the nanofibers. Most particles are wrapped in the nanofibers, while some sections of nanofibers contain pure PVP without any Fe3O4 particles inside. The aggregation of the Fe3O4 nanoparticles in the nanofibers may be attributed to the following possible reasons: (1) the Fe3O4 nanoparticles are distributed uniformly in PFF due to the different densities between the PVP and nanoparticles. (2) The Fe3O4 nanoparticles tend to agglomerate each other to reduce its own energy in the PFF due to their high surface-to-volume ratio by electrostatic attraction. (3) The external magnetic field during the needleless electrospinning may further exacerbate the aggregation of Fe3O4 particles in the PFF due to the magnetic attraction. The cumulative frequency distribution of the electrospun nanofiber diameters is shown in 3O4 particle concentrations of 0.2 g/mL needleless, 0.25 g/mL needleless, and 0.2 g/mL needle electrospinning, respectively. The average diameter of nanofibers by needleless electrospinning increases with the Fe3O4 particle concentration of PFF. It may be explained by the viscosity of PFF increasing with the Fe3O4 particle concentration of PFF. The standard deviation of needleless electrospinning nanofiber diameter is larger in comparison with conventional electrospinning. It may indicate that the needle electrospinning process is more unstable. Therefore, the needleless electrospinning can prepare magnetic nanofibers with multiple parallel jets under the coincident electric and magnetic fields.The SEM images of PVP/Fe3O4 and neat PVP nanofibers were evaluated by measuring weight loss vs. temperature of the nanofibers. TGA curves of PVP/Fe3O4 and neat PVP nanofibers are shown in 3O4 particles. The degradation temperature of Fe3O4 is beyond 1000 °C. The weights of Fe3O4 particles left are 75% and 77% for the Fe3O4 concentrations of PFF at 0.2 g/mL and 0.25 g/mL, respectively. The concentration of PVP/ethanol solution is 7 wt%. The theoretically weights of Fe3O4 in the nanofibers are 74% at 0.2 g/mL and 78% at 0.25 g/mL. Therefore, the experimental TGA values agree with the theoretical ones.The thermal degradations of PVP/Fe3O4 nanofibers prepared by needleless electrospinning and neat PVP nanofibers by conventional electrospinning. The main absorption peaks of neat PVP shown in −1, 2952 cm−1, 1429 cm−1, 1670 cm−1, and 1282cm−1 are assigned to the O–H stretching, C–H stretching, C–H bending, C=O stretching vibration, and the tertiary amine and C–N vibration, respectively. These absorption peaks observed confirm the existence of PVP groups which are also presented in the FT-IR spectra of PVP/Fe3O4 nanofibers, as shown in −1 is observed in the FT-IR spectra of PVP/Fe3O4 nanofibers. The absorption peak of Fe–O was at around 551 cm−1, according to the previous research [3O4 nanoparticles and nanofibers [3O4 nanofibers at the Fe3O4 concentration of 0.25 g/mL shows a similar profile with that of PVP/Fe3O4 nanofibers at 0.2 g/mL.research . This slnofibers . The FT-3O4 membranes prepared by needleless electrospinning and Fe3O4 particles were obtained by VSM at room temperature, as shown in 3O4 particles and PVP/Fe3O4 membranes, which means they are ferromagnetic. The specific saturation magnetization (sM) values for pure Fe3O4 particles, 0.25 g/mL and 0.2 g/mL PVP/Fe3O4 membranes are 91 emu/g, 70 emu/g, and 55 emu/g, respectively. The decrease in saturation magnetization value of Fe3O4/PVP composite nanofibers in comparison with Fe3O4 nanoparticles can be explained as: firstly, the existence of nonmagnetic PVP components encapsulate Fe3O4 nanoparticles, which affects the magnetization expression of Fe3O4 nanoparticles; secondly, the wide size distribution of Fe3O4 nanoparticles in the nanofibers, as shown in 3O4 membranes is larger than that of 0.2 g/mL PVP/Fe3O4 membranes. sM is proportional to the amount of Fe3O4 in the composite nanofibers [3O4 nanoparticles and Fe3O4/PVP composite nanofibers are all 105 G at room temperature as shown in 3O4 particles, 0.25 g/mL and 0.2 g/mL PVP/Fe3O4 membranes are 10 emu/g and 7 emu/g, and 6 emu/g, respectively. It indicates that ferromagnetic responses are expected at room temperature. A PVP/Fe3O4 membrane at Fe3O4 concentration of 0.25 g/mL was needleless electrospun, as shown in 3O4 membrane with a N40 permanent magnet was observed in 3O4 membrane had a good magnetic response property.Magnetic hysteresis loops of PVP/Fenofibers . The coew = 1,300,000) was purchased from Aladdin Industrial Corporation, Shanghai, China. PVP was dissolved in the ethanol  at a concentration of 7% under sufficiently stirring for about 12 h at room temperature. Fe3O4 nanoparticles  were purchased as ferrite magnetic particles. Magnetite (Fe3O4) has been widely used in biomedical applications, such as magnetic resonance imaging (MRI), drug delivery, biosensors, magnetic separation, and medical diagnostics due to its innate biological compatibility [Poly(vinyl pyrrolidone)  by ultrasonic stirring at 70 °C. Subsequently, the surfactant sodium oleate was slowly added into the Fe3O4 /water solution at a ratio of 1:4 (w/v) and stirred for about 45 min. The modified Fe3O4 particles were precipitated using a strong NbFeB magnet and washed by ethanol solution several times to remove excessive sodium oleate. The modified Fe3O4 particles with sodium oleate were dried. The concentration of PVP/ethanol solution (7%) was prepared, because it was a proper concentration for the electrospinning of PVP nanofibers and good dispersion of Fe3O4 particles. The modified Fe3O4 particles were added to the PVP/ethanol solution at the concentrations of 0.2 g/mL and 0.25 g/mL in this experiment. Then the solution was stirred and dispersed by vortex and ultrasound. A relatively homogeneous polymeric PFF was prepared. The PFF was served as a raw solution for electrospinning of magnetic nanofibers.FeA needleless electrospinning apparatus for the preparation of magnetic nanofibers was self-developed, as shown in H) of 75 mT. The pure iron pillar was further magnetized by the small permanent magnets. The residual flux intensity (rB) and relative magnetic permeability (rμ) of small magnets were 1.24 T and 1.05, respectively. The relative magnetic permeability of the iron pillar was 4000. The PFF was magnetized to form a cone droplet. The magnetic field distribution of the apparatus was numerically calculated with COMSOL Multiphysics 5.0 softwarefigure, as shown in A 6-mm-thickness, 40-mm-diameter grade-N40 large permanent magnet was placed below the PDMS block with a distance of approximately 5 mm. This arrangement created a magnetic field directed normally to the top surface of PDMS block with a uniform flux intensity (The needleless electrospinning procedures for the preparation of magnetic nanofibers were as follows: (1) about 2 µL PFF was poured on a PDMS block with a pipette at each top end of the pillar. (2) The PFF was self-assembled into a droplet cone under the magnetic field. (3) A high-voltage power supply was adjusted at 28 kV and a high electric field was applied to the PFF cone-shape-droplets. The needleless electrospinning occurred and the nanofibers were collected. (4) This needleless electrospinning process was observed by a high-speed camera with a 10× lens . (5) The nanofibers were vacuum dried for 24 h and stored in a vacuum-sealed desiccator to prevent the absorption of moisture.The conventional needle electrospinning of PFF was also employed to prepare magnetic nanofibers. The applied voltage was 12 kV, the tip-to-collector distance was 10 cm and the mass flow rate was 0.8 mL/h. Both the needleless and needle electrospinning were performed at room temperature (25 °C) under a relative humidity of 40–45%.3O4 particles were evaluated using a vibrating sample magnetometer  at room temperature.The prepared magnetic nanofibers were characterized and analyzed by SEM, TEM, TGA, FT-IR, and VSM. The morphology of the resulting nanofibers was observed using a field emission scanning electron microscope . The internal morphology of composite nanofibers was studied using a transmission electron microscopy . The diameter of nanofibers was measured by Image-J image analysis software  with about 100 randomly-selected nanofibers from each SEM image. Thermogravimetric analysis of nanofibers was carried out on a TGA instrument  with a heating rate of 10 °C/min from 25 °C to 700 °C under a nitrogen atmosphere of 50 mL/h. The functional groups of nanofibers were studied by FT-IR . The magnetization versus the applied magnetic field curves (M-H curves) of magnetic nanofibers and Fe3O4 ferrofluid was prepared for the needleless electrospinning. When the PFF droplet is subject to a magnetic field, the PFF shows a static Rosensweig instability with a conical protrusion on the free surface. When the surface is further stressed by an electric field, the tip of the protrusion emits an electrospinning jet. Both the electric and magnetic effects act in concert to draw the meniscus, ultimately causing the PFF jetting and electrospinning. The needleless electrospinning shows a similar process phenomenon in comparison with the conventional electrospinning. The needleless electrospinning jet becomes finer, and is finally deposited on the collector as the magnetic nanofibers. The nanofibers prepared by the needleless electrospinning show similar morphology in comparison with conventional electrospinning. The Fe3O4 particles distribute and aggregate both inside and on the surface of the nanofibers. The magnetic nanofibers consist of Fe3O4 particles and PVP polymer according to the analysis of TGA and FT-IR experiments. The nanofiber membrane also exhibits good ferromagnetic and magnetic field responsive properties. The magnetic nanofibers have potential in biomedical applications.We presented a novel needleless electrospinning method for the preparation of magnetic nanofibers from the self-assembling ferrofluid cone array under simultaneous magnetic and electric fields. The PVP/Fe


Lymnaea learns conditioned taste aversion (CTA) and remembers not to respond to food substances that initially cause a feeding response. The possible relationship between how well snails learn to follow taste-aversion training and brain dopamine contents is not known. We examined this relationship and found the following: first, snails in the act of eating just before the commencement of CTA training were poor learners and had the highest dopamine contents in the brain; second, snails which had an ad libitum access to food, but were not eating just before training, were average learners and had lower dopamine contents; third, snails food-deprived for one day before training were the best learners and had significantly lower contents of dopamine compared to the previous two cohorts. There was a negative correlation between the CTA grades and the brain dopamine contents in these three cohorts. Fourth, snails food-deprived for five days before training were poor learners and had higher dopamine contents. Thus, severe hunger increased the dopamine content in the brain. Because dopamine functions as a reward transmitter, CTA in the severely deprived snails (i.e. the fourth cohort) was thought to be mitigated by a high dopamine content.The pond snail  Summary: Severely food-deprived snails cannot acquire conditioned taste aversion, because this conditioning is thought to be mitigated by a high content of a reward transmitter, dopamine, in these snails. Lymnaea stagnalis, as well as other molluscs, both pharmacological and immunohistochemical studies of dopaminergic pathways have been conducted  is formed following training where we pair presentation of a sucrose solution  and an electric shock  . In snairivation ; and (2)l-DOPA) and 3,4-dihydroxyphenylacetic acid (DOPAC) content of the brains simultaneously. l-DOPA is the precursor molecule of dopamine, and it is converted to dopamine by l-aromatic amino acid decarboxylase at rates so rapid that DOPA contents in the mammalian brain are negligible under normal conditions (O-methyltransferase (COMT) and MAO ; (C) snails that had been food-deprived for 1 day , that is, Day −1 snails could eat freely before the start of CTA training, whereas Day 1 snails experienced food deprivation at least 1 day before the training; and (D) snails that had been food-deprived for 5 days  (We used four cohorts of naive snails for the CTA training: (A) snails that were in the act of eating just before the commencement of the CTA training procedure (i.e. Eating snails); (B) snails that had been given  snails) ,b.In the pre- and various post-test sessions  given to all four cohorts of snails, we counted the number of bites in response to the CS (sucrose) for 1 min. In all four cohorts of snails, we performed two controls, backward conditioning and naive training; and we found no significant decrease in the feeding response to the CS in these control groups.P<0.05), the number of bites 1 h, 1 day and 1 week later were not different from the pre-training levels (P>0.05). In this cohort of snails, the feeding ratio between the result of the pretest and that of the 10-min post-test was determined to be 61%.We found that the state of eating before training had a significant impact on how well or how poorly the snails learned and remembered. CTA-trained snails that were in the act of eating (Eating snails) showed learning but not memory formation A. That iad libitum, they were not eating just before training). In these snails, following training the response to the CS was significantly suppressed at the 10-min post-test . Thus, the snails in this cohort learned and formed memory. When we determined the feeding ratio of this cohort, it was found to be 45%.The next cohort of snails tested was the Day −1 cohort . We found that these snails exhibited excellent learning and memory formation in all the post-training sessions P<0.01, C. When wWe conclude that the state of the snail as regards its eating history, or lack thereof, significantly alters how well or how poorly they learn and form memory following CTA training.Having obtained the behavioral data from the four cohorts, we then measured the dopamine content of their brains using high-performance liquid chromatography with an electrochemical detection system (HPLC-ECD). The dopamine content of the Eating snails, which were eating just before training, was higher than the snails that had access to food but were not eating (i.e. Day −1 snails). Further, the dopamine content of Day −1 snails was higher than the snails that were food-deprived for one day . We then compared the behavioral grades earned by these three cohorts  with their respective dopamine contents , and fouP<0.05) than that of the Day 1 cohort, and these Day 5 snails were the poorest learners  was significantly higher  the contents of measured A. To easmeasured B. We couIn molluscs, dopamine plays an important role in appetitive classical conditioning . Here weIn the present study, we cannot claim that there is causality between the CTA grades and the dopamine contents in the brain, especially for the data obtained from Day 5 snails. However, we need to keep in mind the following:Lymnaea  Food deprivation suppresses the egg-laying behavior in Lymnaea . The eggLymnaea . That is(2) The Day 5 snails received both the poorest grade and had the highest dopamine contents . It turnWe also know that there is a possible interaction between insulin and dopamine in the expression of CTA memory. We found previously that following the injection of insulin into Day 5 snails, CTA was observed . We are l-DOPA content was significantly higher than those of dopamine and DOPAC  snails, the nd DOPAC . l-DOPA  mammals , 2003. Arization . Recentl mammals . In Lymnbehavior . Additioand CNQX , suggestlutamate . Taken tLymnaea with various eating histories. In the future, we will also pay attention to the serotonin contents, as they are also affected by eating history  with an 18-23 mm shell obtained from our snail-rearing facility  were used in the present study ] and a commercially available product called ‘spiral shell food’  every other day. Lymnaea exhibit good growth and reproduction under these conditions  as an internal standard. After centrifugation of the homogenate , 40 µl of supernatant was collected. Dopamine, l-DOPA and DOPAC in the single brain were measured using high-performance liquid chromatography (HPLC) with electrochemical detection . The number of single brains used was 10 for each group. The brain included all ganglia. The mobile phase containing 0.18 M chloroacetic acid and 16 µM disodium EDTA was adjusted to pH 3.6 with NaOH. Sodium-1-octanesulfonate at 1.85 mM as an ion-pair reagent and CH3CN at 8.40% (v/v) as an organic modifier were added to the mobile phase solution. The chromatographs were acquired using the computer program PowerChrom . The supernatants of samples were injected directly onto the HPLC column. The snails used for the measurement of dopamine were independent from those used for behavioral experiments to avoid the effects of sucrose application on the dopamine contents.The measurement method was as described previously , with a P<0.05).Data are expressed as the mean±s.e.m. Differences in the contents were tested using one-way ANOVA and post hoc Tukey test or Scheffé test (


Nanofibers with excellent activities in surface-enhanced Raman scattering (SERS) were developed through electrospinning precursor suspensions consisting of polyacrylonitrile (PAN), silver nanoparticles (AgNPs), silicon nanoparticles (SiNPs), and cellulose nanocrystals (CNCs). Rheology of the precursor suspensions, and morphology, thermal properties, chemical structures, and SERS sensitivity of the nanofibers were investigated. The electrospun nanofibers showed uniform diameters with a smooth surface. Hydrofluoric (HF) acid treatment of the PAN/CNC/Ag composite nanofibers (defined as p-PAN/CNC/Ag) led to rougher fiber surfaces with certain pores and increased mean fiber diameters. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results confirmed the existence of AgNPs that were formed during heat and HF acid treatment processes. In addition, thermal stability of the electrospun nanofibers increased due to the incorporation of CNCs and AgNPs. The p-PAN/CNC/Ag nanofibers were used as a SERS substrate to detect p-aminothiophenol (p-ATP) probe molecule. The results show that this substrate exhibited high sensitivity for the p-ATP probe detection. Surface-enhanced Raman scattering (SERS) is a hypersensitive, noninvasive, and powerful analytical technique for the ultimate identification of small molecules through enhancing Raman signals of the molecules located in the region of noble metals or their nanostructures ,2. NobleElectrospinning has become a practical technique for production of nanofibers with diameters commonly ranging from tens to hundreds of nanometers because of its versatility and cost-effective setup ,9,10. ThNanocellulose is a sustainable nanomaterial, well-known for its abundance, biodegradability, and biocompatibility . NanocelLow-dimensional silicon (Si) nanostructures have been intensely investigated and the electrochemistry of Si has spurred intense research activity in microelectronic technology . SiliconHerein, we describe a facile synthesis approach to functionalize PAN with CNCs and AgNPs and produce electrospun nanostructures for SERS substrate applications. In the system, SiNPs were also used as a template for electrodeless deposition of Ag. The p-aminothiophenol (p-ATP) was selected as the model material for SERs detection because it is one of the most typical and excellent materials in SERS measurement. w = 150,000 g/mol), N,N-dimethylformamide (DMF), Hydrofluoric acid (HF), and silver nitrate (AgNO3) were purchased from Sigma-Aldrich . Cellulose nanocrystals  were purchased from Blue Goose Biorefineries Inc. . Silicon nanoparticles (Si NPs) were purchased from Shanghai St-nano Science and Technology Co., Ltd. . The p-aminothiophenol (p-ATP) was purchased from Shanghai Mackin Biochemical Co. Ltd. . All chemicals were used directly without further treatment.Polyacrylonitrile . Dried CNC powder was added in DMF and the mixture was vigorously stirred for 48 h at room temperature to make a suspension with a CNC concentration of 0.2% . Then the obtained CNC suspension was added into the PAN solution under magnetic stirring for 2 h to get the homogeneous PAN-CNC-DMF suspension. SiNPs and AgNOEach prepared precursor suspension was loaded into a 5 mL Becton-Dickinson (BD) plastic syringe  and equipped with a stainless-steel needle tip . Then the syringe was driven by an electric syringe pump  set at a fixed flow rate of 0.5 mL/h. The needle was connected to a high-voltage power supply , and the positive DC voltage was fixed at 18 kV. An aluminum foil-covered metal plate was horizontally placed to collect the nanofiber with a needle tip-to-plate distance of 18 cm. The collected nanofiber mats were dried in a vacuum oven at 40 °C to remove the residual solvent. The obtained electrospun nanomats are designated as PAN, PAN/Ag, PAN/CNC/Ag, and PAN/CNC/Ag/Si.The PAN/CNC/Ag/Si nanofibers were further immersed into a HF solution (5 wt %) for 30 min to remove SiNPs embedded in the nanofibers. The process also led to electrodeless conversion of AgNPs from Ag ions. The nanomats were then washed with deionized water for several times and dried in a vacuum oven at 40 °C. The HF acid treated PAN/CNC/Ag/Si nanofiber mats contained fibers with some pores and are designated as p-PAN/CNC/Ag.−1 at 25 °C. In order to avoid solvent evaporation, a solvent trap cover was used during the measurements.A rheometer  was used to measure the shear viscosities of the precursor suspensions with a 40-mm cone-plate geometry. The viscosity for each suspension was recorded at shear rates ranging from 0.1 to 1000 sSurface morphologies of the electrospun nanomats were observed using a FE-SEM  under an accelerating voltage of 5 kV. The surfaces of the mats were coated with a thin layer of gold before observation. The diameters of the nanofibers were obtained using the image processing software (ImageJ 1.48) through measuring 50 randomly chosen individual nanofibers from the FE-SEM images. To characterize the dispersion and size of Ag nanoparticles in the electrospun fibers, high resolution transmission electron microscopy  operating at an accelerating voltage of 200 kV was used.α radiation .The crystalline structures of the electrospun nanostructures were determined using Bruker/Siemens D5000 X-ray diffractometer . The experiments were conducted from 5° to 80° using a scan speed of 0.2°/min with Cu-Kα irradiation (1486.61 eV) at 10 kV and 10 mA current. Survey spectra were recorded from 0 to 1200 eV with a pass energy of 40 eV and a step size of 1.0 eV.X-ray photoelectron spectroscopy (XPS) analysis was performed on a Specs PHOIBOS-100 spectrometer  with an Al-K−1 and each sample was scanned in the range of 4000–400 cm1−.An FTIR spectrometer  was used to observe the chemical structure of the electrospun nanostructures. The resolution of the IR spectrometer was 4 cm2 atmosphere (flow rate = 100 mL/min).Thermal properties of the samples were studied with a SDT Q600 analyzer . The spontaneous thermogravimetric (TG), differential thermogravimetric (DTG), and differential scanning calorimetry (DSC) data of the samples were recorded from room temperature to 800 °C at a heating rate of 10 °C/min. The test was conducted in N−4 mol/L of p-ATP solution for 30 min. Then, the material was dried at 60 °C and attached to silicon substrates for measurement. The SERS spectra of each nanostructure containing p-ATP probe molecules were acquired at a randomly selected spot on the substrates using a LabRAM HR800 confocal Raman spectroscopy  from 400 to 1800 cm−1. An yttrium aluminum garnet (YAG) laser 532 nm was used as excitation source.For the SERS tests, p-ATP was used as the probe molecule. A sample of 10 mg from each prepared nanostructure material was immersed in 1.0 × 10−1 are shown in The most important factor for successful preparation of electrospun nanostructures is to form a homogeneous precursor suspension. In this study, homogeneous suspensions consisting of PAN, CNCs, AgNPs, and SiNPs were obtained using DMF as solvent. The shear viscosities of the precursor suspensions at the range of 0.1–1000 sThe PAN solution showed the Newtonian behavior at low shear rates. At higher shear rates, the PAN solution viscosity decreased with increase in the shear rate. During this process, the PAN molecular chains were gradually disentangled by increased shear stress, and thus a pseudoplastic behavior of the solution was observed at higher shear rates. For PAN/CNC suspension, the plateau disappeared and the viscosity displayed nearly Newtonian behavior within the whole investigated shear region. The viscosity of PAN/CNC suspension was much lower compared to that of PAN, which might be caused by the distortion of PAN molecular chain-chain interactions with the CNCs. Compared to PAN/CNC, the PAN/CNC/Ag and PAN/CNC/Ag/Si suspensions showed almost the same viscosities except that these two suspensions had slightly higher viscosity at low shear rates, which was caused by the increased concentrations of the electrospinning suspensions after the addition of Ag NPs and Si NPs.3 system [+ reduction ).3 system . The reaThe corresponding size distributions of the above nanofibers are listed in The crystalline structure of electrospun nanostructures was verified by XRD as shown in 5/2 and Ag 3d3/2 energy levels, respectively. The spine energy separation is 6 eV, reflecting the metallic nature of Ag [2O3, which may be caused by the residual solvent and aluminum foil used to collect the fibers [XPS measurement was used to analyze the chemical composition and electronic structures of the prepared p-PAN/CNC/Ag nanofibers . As showre of Ag ,3,35. Thre of Ag . Figure re of Ag . It sugge fibers . −1 corresponded to CN stretching vibration, CH2 bending vibration, CH wagging, and skeletal vibration of the PAN molecular chain, respectively [−1 are attributed to the O–H bending of adsorbed water. The peaks at 1340–1380 are assigned to the aliphatic CH group vibrations of CH2. Compared to those of pure PAN, the spectra of PAN/CNC/Ag and PAN/CNC/Ag/Si nanofibers show new peaks at 1034 cm−1 and 824 cm−1 corresponding to the characteristic absorption bands O–H of CNCs and C–H rock respectively [The FTIR spectra of the electrospun nanostructures are shown in ectively ,37,38. Tectively , which iThe TGA, TGC, and DSC curves of the electrospun nanostructures are shown in The DSC curves of PAN nanofibers showed a sharp exothermic peak at 288 °C B, which −1 (C–S stretching mode ) and 1598 cm−1 (C–C ring breathing) [−1, δ (C–H) at 1184 cm−1, ν (C–C) and δ (C–H) at 1327 cm−1, δ (C–H) and ν (C–C) at 1499 cm−1, and ν (C–C) at 1584 cm−1 were significantly enhanced. It should be pointed out that the enhancement degree varied with different band width. Thus, there is no single enhancement factor over the entire spectra. Since the band at 1583 cm−1 can demonstrate the band for b2 bending modes [−1 position was selected for estimating the SERS enhancement factor (EF) values. The normal Raman spectrum of solid p-ATP is shown in 3. These results demonstrate that p-ATP adsorbed to the surface of the p-PAN/CNC/Ag nanomats and resulted in the remarkable Raman enhancement. The CNCs in the PAN/CNC/Ag system acted as a coordination agent for the formation of AgNPs. In short, the as-spun nanostructures can be used as effective SERS substrates for cost-effective SERS applications. The PAN matrix allows the nanofibers to keep their morphology after immersing into sample solution, a distinct advantage when compared with published data in other work [The PAN/Ag nanofibers substrates without CNCs showed no SERS for p-ATP probe molecule . The PANher work .The p-PAN/CNC/Ag composite nanofibers were successfully fabricated by a convenient electrospinning technique using PAN, AgNPs, SiNPs, and CNCs as main fiber composition. The fibers exhibited excellent activities for SERS. Silver nitrate was reduced to AgNPs during the heat and the HF acid treatment processes, which was confirmed by XRD and XPS results. The electrospun nanofibers showed uniform diameters with a smooth surface, but for the p-PAN/CNC/Ag composite nanofibers the surface became rougher with pores and the fiber diameter increased. In addition, the incorporation of CNCs, AgNPs, and HF treatment increased the thermal stability of the electrospun nanofibers. Ultimately, the novel material p-PAN/CNC/Ag composite nanofibers were successfully demonstrated as a useful SERS substrate for applying to the p-ATP probe molecules. The functionalized nanofibers pave a new way in developing a membrane for sensors, catalytic materials, and other devices.