N,N-dimethylacetamide as the solvent) and polyvinylpyrrolidone  as the polymeric models, relationships between the working temperature  and nanofiber diameter  were established, with D = 12598.6 − 72.9T + 0.11T2 (R = 0.9988) for PAN fibers and D = 107003.4 − 682.4T + 1.1T2 (R = 0.9997) for PVP nanofibers. Given the fact that numerous polymers are sensitive to temperature and numerous functional ingredients exhibit temperature-dependent solubility, the present work serves as a valuable reference for creating novel functional nanoproducts by using the elevated temperature electrospinning process.Temperature is an important parameter during electrospinning, and virtually, all solution electrospinning processes are conducted at ambient temperature. Nanofiber diameters presumably decrease with the elevation of working fluid temperature. The present study investigated the influence of temperature variations on the formation of polymeric nanofibers during single-fluid electrospinning. The surface tension and viscosity of the fluid decreased with increasing working temperature, which led to the formation of high-quality nanofibers. However, the increase in temperature accelerated the evaporation of the solvent and thus terminated the drawing processes prematurely. A balance can be found between the positive and negative influences of temperature elevation. With polyacrylonitrile (PAN, with  Electrostatic energy has gradually increased its share from other types of energies  in creating nanoproducts through a top-down manner. Popular examples of such nanoproducts are electrospun nanofibers and electrosprayed nanoparticles –3. In thCurrently, the development of electrospinning focuses on two directions. One is the large-scale production of electrospun nanofibers for commercial products through edge, multiple-needle, needle-less, and slit electrospinning –9. HowevAnother development direction for electrospinning is to generate novel types of nanostructures and nanofibers. These nanostructures include the popular core–sheath fibers, tri-layer nanofibers, Janus nanofibers, and the complicated nanostructures from a combination of core–sheath and Janus –15. HoweN-methylmorpholine oxide and water through elevated temperature electrospinning but provided no detailed information on the heating unit. De Vrieze et al. [Although temperature is a key parameter in electrospinning, the related reports are extremely limited, which is possibly correlated with the simple implementation of electrospinning under ambient conditions. The key in running elevated temperature electrospinning lies in heating and maintaining the working fluid at a constant temperature different from ambient conditions. Steven et al.  utilizede et al.  investig3H3N)n, PAN is a versatile polymer used to produce a large variety of products, including ultrafiltration membranes, hollow fibers for reverse osmosis, and fibers for textiles. This polymer is used as the chemical precursor in 90% of high-quality carbon fiber production and is also extensively used in electrospinning; PAN nanofibers are good precursors for preparing carbon nanotubes (CNTs) [N-vinylpyrrolidone. This polymer is soluble in water and other polar solvents. PVP is used as binders in pharmaceutical tablets and as additives in batteries, ceramics, fiberglass, inks, and inkjet paper; this polymer is also used in the production of membranes, such as dialysis and water purification filters, as well as in the solubility enhancement of poorly water-soluble drugs [N,N-dimethylacetamide (DMAc), which displays a high boiling point of 166 °C. PVP features good spinnability in the typical protic solvent ethanol, with a boiling point of 78.4 °C. The two working solutions can represent almost all types of polymer solutions exploited for electrospinning in creating the corresponding nanofibers.The above-mentioned publications successfully demonstrated the usefulness about the combined utilization of thermal energy and electrostatic energy in creating polymeric nanoproducts with an elevated temperature of the working solutions. However, none of these works systematically investigated the influence of temperature on fiber formation. In the present work, polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) were utilized as the model filament-forming polymers. A synthetic and semicrystalline organic polymer resin with the linear formula (Cs (CNTs) , 24. PVPle drugs , 26. PANN,N-Dimethylacetamide (DMAc) and anhydrous ethanol were provided by Shanghai Chemical Reagent Co., Ltd. . All chemicals used were of analytical grade.PAN powders  were obtained from Shangyu Baisheng Chemical Technology Co., Ltd. . PVP K90  was purchased from BASF Shanghai Co., Ltd. . w/v). To ensure a homogeneous working fluid, the PAN solution was agitated over 12 h at 80 °C and then was cooled to the ambient temperature. The other solution was PVP K90 in anhydrous ethanol with a concentration of 9% (w/v) and was prepared under ambient conditions.Two electrospinnable solutions were prepared to implement elevated temperature electrospinning. One solution contains PAN in DMAc with a concentration of 15% , a pump , a spinneret , a collector , and an accessory for heating and manipulating the working fluid temperature. The detailed parameters for creating PAN and PVP nanofibers are included in Table The morphology of electrospun fibers was assessed through field-emission scanning electron microscopy . Prior to examination, samples were sputter-coated with platinum to prevent charging during FESEM imaging. ImageJ software  was utilized to measure the fiber diameter from SEM micrographs. For each sample, nanofiber size was measured at over 100 points.The surface tensions and viscosities of the PVP solution were measured as a function of working temperature. The former was carried out with a BZY-1 Surface Tension Tensiometer . The latter was conducted using a NDJ-279 rotary viscometer . An HZBZ-08 Automatic saturated vapor pressure measuring instrument  was exploited to measure the saturated vapor of anhydrous ethanol at different temperatures (20.0–78.0 °C) by using a static method [A typical electrospinning system consists of four components Fig. , namely,In the present work, the inner structure of the auxiliary apparatus is shown in Fig. All electrospinning processes of PAN solutions were implemented smoothly and continuously under the selected operative conditions, including a series of working temperatures of 20, 40, 60, and 80 °C. A digital image of the running processes is exhibited in Fig. Four types of PAN nanofibers prepared under different working temperatures are shown in Fig. The statistical results of all four PAN nanofibers are shown in Fig. y = ax + b), power function equation (y = axb), and one-variable quadratic equation (y = ax2 + bx + c). Among these equations, the quadratic equation D = 12598.6 − 72.9T + 0.11T2 showed the best fitting result, with a correlation coefficient of 0.9988  and T represents the working temperature (K). According to this equation, an inflection point can be found at T = 342 K, i.e., 69 °C. Under this working temperature, the thinnest PAN nanofiber with a diameter of 250 nm was achieved  was deduced. Thus, they concluded that high temperature induces the production of ultrathin fibers. According to their equation, higher working temperature indicates smaller η of the working fluid and, thus, smaller diameter of resultant nanofibers. The fundamental explanation that supports this result is that an increase in temperature would decrease the viscosity of polymer solutions but exert minimal influence on physical entanglements, which act to prevent capillary breakup for the formation of linear electrospun nanofibers from polymer solutions. Evidently, our results do not agree with this declaration.Wang et al.  producedA schematic of the influence of working temperature on fiber formation is suggested in Fig. The faster solvent evaporation under high temperatures than under ambient conditions should create different rigid PAN fiber precursors  with less content of the residual DMAc. Logically, the later evaporation of the solvent from the native polymeric nanofibers assembled on the collector would deform the final nanofibers, often generating a rough surface owing to barometric pressure . Thus, tTo investigate further the influence of temperature and the related solvent evaporation on the formation of nanofibers, a different solution system consisting of PVP dissolved in anhydrous ethanol  was explored on the elevated temperature processes. The preparations of PVP nanofibers F5, F6, F7, and F8 at ambient temperature 30, 40, and 50 °C could be implemented continuously and robustly. However, electrospinning at a high temperature of 60 °C for producing PVP nanofiber F9 was fragile and unsteadily. The generation of ethanol vapor from the PVP solution induced the separation of the working fluids into two separate phases in the glass syringe. In the PVP solution, the separated ethanol vapor caused intermittent stoppage of the spinning process and sometimes spurted a pool of liquids.The prepared PVP nanofibers F5 to F8 exhibited good linear morphology and uniform distributions Fig. . The enly = ax2 + bx + c), an equation of D = 107003.4 − 682.4T + 1.1T2 with a correlation coefficient of 0.9997  and T represents the working temperature (K). According to this equation, the inflection point is at T = 312 K, i.e., 39 °C. Under this working temperature, the thinnest PVP nanofiber with a diameter of 415 nm was achieved . Near the liquid exists a thin layer of vapor, which is often termed as the evaporation layer or Knudsen layer Fig. a, named Lc) can be estimated according to the following equation [The Knudsen layer thickness  became smaller and smaller , where y is Ts/ps and x is the temperature. At 60 °C, the thickness of the Knudsen layer was only 38% of that at 20 °C. Thus, higher working temperature indicates smaller Ts/ps value and thinner Knudsen layer, corresponding to the faster evaporation of the solvent and solidification of the PVP fluid jets. The premature solidification of the fluid jet under an excessively high temperature will exert a negative influence to stop the drawing under the electric field, thereby producing fibers with large diameters.As evidently seen from the equation, the elevation of temperature will result in a thicker Knudsen layer. However, the increase in temperature will simultaneously increase the saturated pressure and consequently result in a thinner Knudsen layer. As the temperature was gradually increased, int Fig. b. Duringler Fig. c. The KnD = 12598.6 − 72.9T + 0.114T2 (R = 0.9988) and D = 107003.4 − 682.4T + 1.1T2 (R = 0.9997), respectively. Given the fact that numerous polymers are sensitive to temperature and numerous functional ingredients exhibit temperature-dependent solubility, the present work serves as a valuable reference for creating novel functional nanoproducts through elevated temperature electrospinning. Manipulating the working temperature can also be combined into the coaxial, side-by-side, and tri-axial electrospinning processes to extend the applications of these techniques in creating novel functional nanomaterials.With PAN solutions in DMAc and PVP K90 solutions in ethanol as the model working fluids, elevated temperature electrospinning processes were successfully carried out to synthesize nanofibers under a series of working temperatures by using a homemade electrospinning system. Regardless of protic solvent (ethanol) or aprotic solvent (DMAc) and their volatilization property, elevated working temperature generated both positive and negative influences on the formation of polymer nanofibers. Temperature elevation decreased surface tension and viscosity, which consequently resulted in facile electrospinning and downsized resultant products. However, temperature elevation also directly influenced the electrical drawing during electrospinning by accelerating the evaporation of the solvent from fluid jets. Excessively high working temperatures led to the premature termination of the electrical stretching of polymer fluid jets, thus exerting a negative influence on the produced fibers with large diameters. The PAN and PVP nanofibers produced under reasonable conditions exhibited fine linear morphology without any observed beads-on-a-string or spindles-on-a-string phenomenon. The fitting equations for PAN and PVP nanofibers are


A new proposal is given to control local magnetic field in a molecular junction. In presence of finite bias a net circular current is established in the molecular ring which induces a magnetic field at its centre. Allowing a direct coupling between two electrodes, due to their close proximity, and changing its strength we can regulate circular current as well as magnetic field for a wide range, without disturbing any other physical parameters. We strongly believe that our proposal is quite robust compared to existing approaches of controlling local magnetic field and can be verified experimentally. The study of electronic transport through single molecules has been the objects of intense research due to the fact that molecular components can be utilized as significant functional elements in electronic devices. In 1974 Aviram and Ratner2345678910111213141516local magnetic fields in molecular systems came into limelight following the realization of controlling spin orientation2930Though a wealth of literature knowledge has been established in the field of molecular transport, most of the works have focused essentially on net junction current, while very few attempts have been made18192021222324252424252728Though several suggestions were made for the possible exploitations of such high local magnetic fields at the molecular regime, probably the most significant application can be the generation of spin-based quantum computers33343524253940In the present paper we essentially focus on how to control circular current and associated magnetic field in a molecular junction having single or multiple loops coupled to source and drain electrodes. Due to close proximity electrons can directly hop between the end atomic sites of these two electrodes and tuning this coupling strength, which is done simply by changing the orientation/position of these electrodes, we can regulate circular current and associated magnetic field in a wide range. No one has addressed this issue before, to the best of our concern, and certainly gives a new insight to modulate electron transmission through a nano-junction.new path in addition to the conventional path i.e., the molecular ring.The molecular junction is schematically shown in H = HM + HS + HD + HT, where HM corresponds to the Hamiltonian for the molecule, HS(D) represents the Hamiltonian for the source(drain) electrode and HT gives the tunneling Hamiltonian. In TB framework these sub-Hamiltonians are expressed as follows:To describe this model we use tight-binding (TB) framework, which is most convenient for analyzing electron transport through a molecular junction particularly in the limit of non-interacting electrons. The full Hamiltonian of the molecular junction can be written as: ci correspond to the creation and annihilation operators, respectively, for an electron at i-th site of the molecular ring, while these operators are an and bn for the source and drain electrodes, respectively. The molecule is characterized by the on-site potential t, whereas for the side attached electrodes these parameters are t0, respectively. tS describes the molecular coupling with the source and it is tD for the drain. These electrodes are connected at the sites p and q (which are variable and nearest-neighbors). For this molecular junction , net junction current at absolute zero temperature for a particular voltage bias V is determined from the relation46Using the transmission function EF is the equilibrium Fermi energy.where i and i + 1, it becomes2425Now to find circular current in the molecular ring we need to calculate current carried by individual bonds. For any such bond, connecting the sites where L = Na, a being the lattice spacing and N represents the total number of atomic sites in the bridging molecule. We assign a positive sign to a current flowing in the anti-clockwise direction.where r (say) inside the molecule can be determined using the Biot-Savart’s law2425394041Due to this circular current a net magnetic field is established. The local magnetic field at any arbitrary point μ0 is the magnetic constant.where t = 2.5 eV, while for the side-attached electrodes they are: t0 = 3 eV. The molecule-to-electrode coupling parameters (tS and tD) are fixed at 1 eV, and the equilibrium Fermi energy EF is set at zero. The values of other physical parameters, those are not same for all figures, are specified in appropriate places. To calculate magnetic field we assume the perpendicular distance from the centre of the benzene ring to any C-C bond is ~0.13 nmBased on the above theoretical framework now we present our results which include two-terminal transmission probability, junction current, circular current and associated magnetic field at the ring centre. There are some physical parameters those values are kept constant throughout the numerical calculations. These parameter are described as follows. In the molecular ring we choose tc) affects circular current and induced magnetic field, let us focus on transmission probability and junction current. In tc. For tc = 0 fine resonant peaks associated with energy eigenvalues of the molecular ring are obtained while the transmission probability drops very close to zero for all other energies. This behavior has already been discussed in several earlier papers1217tc. Apparently it shows that electron gets transmitted almost for the entire energy window and the transmission amplitude gradually increases with the rise of tc. But, a careful inspection yields many fascinating points. To reveal this fact we select a small part of the spectrum, the dashed framed region, and place its zoomed version in the inset. Very interestingly we see that a sharp dip (vanishing transmission) appears at ~E = 1 eV, and above and below this dip resonant curves exhibit completely opposite behavior. One side of this dip, the height of the peak increases while in the other side it gradually decreases with respect to the coupling parameter tc. This feature is also observed in other energies where a transmission peak is followed by a dip. It is an important observation since one can get higher and/or lower electronic transmission at different energies simply by tuning the external coupling parameter tc, without changing any other physical variables. The anomalous feature in this ring-like geometry is observed due to the presence of the new path between the electrodes. A combined interference effect among electronic waves passing through different arms  leads to such a nice phenomenon, and of course would not be noticed in molecular junctions without any loop structure. Thus a competition takes place between the interfering paths i.e., the molecular arms and the external path, and the response depends on the resultant of all these paths. For strong enough tc electrons mostly follow the external path, avoiding the conventional molecular ring.Before going to the central part of our analysis i.e., how direct coupling . This sudden jump is associated with the crossing of one of the resonant energy levels which is clearly seen from the T-E spectrum  compared to the molecular junction without any tc (red line), but eventually the current increases sharply with tc, following the T-E curve , circular current (Ic) changes its sign in different voltage regimes for any side (positive or negative) of the applied bias. And also the magnitude of Ic may be sufficiently large compared to the transport current IT, depending on the external voltage V. For narrow voltages when no resonant energy level appears within the voltage window we get vanishing circular current. While a non-zero contribution comes when anyone of such energy levels lies within the voltage window. With increasing voltage more and more resonant energy levels appear within the window and all of them contribute to the current, resulting a net circular current which may be positive or negative depending of the sign of the dominating energy levels . Though junction current always increases with voltage bias in conventional conducting junctions . Most importantly, the magnetic field which is developed at the ring centre as a result of this circular current is surprisingly high, and it increases significantly with tc. For a wide voltage region (>~2 V) the magnetic field remains almost constant for any specific tc  which contributes to the current. But as we increase tc the other resonant energy levels also appear within this bias window and contributes current in opposite direction with respect to the earlier one yielding a reduction of current. Finally, when they become exactly opposite with each other a vanishing net current is obtained. Beyond this critical value of tc both these states contribute in the same direction providing a resultant higher circular current. From this behavior it can be manifested that tuning the coupling between source and drain electrodes one can regulate circular current and thus locally control induced magnetic field for a wide range starting from zero to few Tesla. Certainly this phenomenon gives a new way of controlling magnetic field in a specific region without disturbing any physical parameters of the system and can be utilized in designing effective spin based quantum devices.In order to see more clearly the dependence of circular current and associated magnetic field on tc for different voltages can be clearly understood from the variation of bond currents, as circular current is determined from the bond currents  and for the other (tc = 0.75 eV) Ic becomes positive in tc bond current changes its sign with voltage. At the same footing for a fixed bias voltage the sign reversal of bond current also takes place with the change of tc yielding a change of sign of the circular current Ic.The sign reversal of circular current, and hence the induced magnetic field, with currents . The varThe results presented above are worked out for the molecular wire containing only the benzene molecule. So the question naturally comes whether similar kind of behavior is observed in other molecular wires with higher number of loops. To answer it now we analyze the behavior of circular current and associated magnetic field of other relevant molecular structure, namely, porphyrin, that is connected with the source and drain electrodes as prescribed in In this work we have demonstrated how to control local magnetic field in a wide region  considering a simple molecular structure by introducing a new path between two electrodes. Using the wave-guide theory, we have calculated two-terminal transmission probability, junction current, circular current and current induced magnetic field at ring centre(s) based on a coherent tight-binding framework. Our finding, to the best of our concern, gives a unique idea of regulating electron transport through a conducting junction.How to cite this article: Patra, M. and Maiti, S. K. Modulation of circular current and associated magnetic field in a molecular junction: A new approach. Sci. Rep.7, 43343; doi: 10.1038/srep43343 (2017).Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.


Klinefelter Syndrome (KS), the most common chromosomal disorder in men , is associated with numerous comorbidities. Based on a number of isolated case reports, we performed the first systematic and comprehensive evaluation of eye health in KS patients with a focus on ocular structure and vascularization. Twenty-one KS patients and 26 male and 38 female controls underwent a variety of non-invasive examinations investigating ocular morphology  and function . In comparison to healthy controls, KS patients exhibited a smaller foveal avascular zone and a decreased retinal thickness due to a drastically thinner outer nuclear layer. The cornea of KS patients showed a decreased peripheral thickness and volume. In perimetry evaluation, KS patients required brighter stimuli and gave more irregular values. KS patients show an ocular phenotype including morphological and functional features, which is very likely caused by the supernumerary X chromosome. Thus, KS should not be limited to infertility, endocrine dysfunction, neurocognitive and psychosocial comorbidities. Defining an aberrant ocular morphology and function, awareness for possible eye problems should be raised. KS leads to a heterogeneous phenotype and is associated with an increased morbidity and mortality2. Prominent features are infertility, hypogonadism, gynecomastia, disturbed bone metabolism, diabetes, neurocognitive and psychosocial comorbidities6. Hence, the predominant symptoms are of endocrine and reproductive nature, nevertheless, more comorbidities associated with aberrant vascularization have been reported recently, e.g. altered testicular vascularization, cardiovascular problems including risk for pulmonary embolism and infarction as well as altered cardiac rhythmogenic properties11. Based on these findings, we hypothesized that ocular blood flow in these patients might also be affected, since the eye is strongly perfused and reacts sensitive to vascularisation changes. Although KS is investigated since its discovery in 194212, eye health and function of KS patients have never been assessed systematically beyond few isolated case reports demonstrating ocular abnormalities in 47,XXY patients19. However, whether these findings are directly related to the KS syndrome as such remains elusive. Therefore, we performed a systematic study to analyse whether KS has general ocular consequences.Klinefelter Syndrome (KS) is the most common chromosome disorder in men (1: 500) that is caused by meiotic non-disjunctions in parental germ cells resulting in a supernumerary X chromosome. 80–90% of the patients exhibit a karyotype of 47,XXY, while in the remaining patients higher grade X chromosomal aneuploidies are observedFor the first time, the full spectrum of non-invasive examinations was used to approach the eye health of KS patients systematically by analysing morphological  and functional aspects . Taken together, our results addressed the eye health in KS patients compared to healthy controls.2, interquartile range [IQR]: 0.14–0.24 mm2) by about 35% compared to controls . In the deep layer, KS patients revealed also a smaller FAZ  of approximately 21% compared to controls .The size of the foveal avascular zone (FAZ) was assessed in the superficial and deep retinal layers Fig. . In the Using OCTA, vessel density was evaluated in the angiograms of superficial and deep retinal layers and in the choriocapillaris (CC). After correction for different FAZ sizes, superficial VD values in the fovea as well as in the parafovea did not differ between groups Table . CompareAnalysis of retinal thickness revealed a substantially decreased retinal thickness by approximately 17 µm (or 5%) in all sectors in KS patients compared to female and male controls Fig. . ThickneSegmentation analysis revealed a decreased thickness for the outer nuclear layer in KS patients  compared to women  compared to women  and pattern standard deviation (PSD) in KS patients compared to controls Table .Table 1CWe performed ophthalmological examinations in a cohort of KS patients versus healthy men and women. In general, KS patients did not notice any subjective ocular symptoms nor attract attention of ophthalmologists. Therefore, function and morphology of the eyes in KS patients have not been studied systematically so far. In this study, we found a distinct ocular phenotype associated with KS.KS patients exhibited a smaller FAZ in the OCT angiograms of superficial and deep layers, a decreased retinal thickness, and a thinner outer nuclear layer. The anterior segment in KS patients exposed a decreased peripheral corneal thickness and volume. In perimetry, KS patients required brighter stimuli and showed a higher irregularity of values in perimetry evaluation.After normalization for the smaller FAZ, there was no difference in relative VD between KS patients and controls in the fovea. In the parafovea, substantial differences in VD were found only between female controls and KS patients in the deep retinal layer. We also found a significant difference in the VD of the parafovea in the deep retina between female and male controls, as indicated by the symbol “+” Table .et al. found a significantly higher VD in females when compared with males in participants older than 60 years, which could be explained by the later vascular aging in females compared to males20. Such differences were not found by another group21.Normative VD data have been presented in different studies in the literature. Coscas et al.22 published that the fovea in preterm babies was vascularised for a certain period of time, Gariano et al.23 and Provis et al.25 showed that the foveal region is avoided at all by growing blood vessels during development in macaques and humans.However, the eye of KS patients exhibits aberrant vascularisation, displayed by a smaller FAZ and thereby a higher absolute vascularisation in the eyes of KS patients. Blood vessels grow further into the foveal centre in KS patients and thereby enlarge the size of the vascular bed. This morphological feature may be an indicator for a dysregulation of angiogenesis during development or an aberrant requirement of the fovea in KS patients in terms of blood support. At the moment, the origin of differences in FAZ sizes is not clear so far, and the mechanism of FAZ formation is also disputed in the literature. Whereas Mintz-Hittner 26. No differences in activity of visual cortex have been described27. In all groups, retinal thickness increased with decreasing size of FAZ in accordance to a previously published record28.We could show an aberrant retinal morphology that manifests in a decreased thickness and segmentation analyses revealed that this thinning was due to a reduced thickness of the outer nuclear layer, which leads to the assumption that a reduced number of photoreceptors is possibly present in the retinae of KS patients, or, less likely, the photoreceptors are more densely packed. Recent publications show anatomical deviations in another part of the central nervous system of KS patients; the brainBesides by CC, photoreceptors are also supplied with oxygen by the vascularisation present in the outer plexiform layer of the retina. Thus, the decreased VD we found in the OCT angiogram of the deep retinal layer compared to female controls and the thinner outer nuclear layer may lead to the speculative assumption that retinae of KS patients might contain a decreased number of photoreceptors. Thinning of the outer nuclear layer in KS patients was more pronounced in the two parafoveal regions than in the fovea. As in the fovea only cones are present and the portion of rods grows with increasing distance from the fovea, the question arises whether rods are more affected than cones by the assumed lack of photoreceptors. The increased MD and PSD values of KS patients during visual field examination might also be associated to less photoreceptors. Whether the reduction of photoreceptor number found in this study and a supposed explicit loss of rods has an effect on visual function of KS patients, in particular on the electroretinogram, remains to be elucidated in further studies.30. This study shows for the first time that KS patients reveal a decreased peripheral corneal thickness and volume compared to healthy controls. Central corneal thicknesses of controls were comparable to the literature32.Accurate corneal thickness measurements has become extremely important in the assessment of different diseases e.g. refractive surgery, glaucoma and keratoconusVD of ONH might reveal higher values in KS patients in comparison to female controls due to larger vessels  that enter and exit the eye through the ONH. Similar to the smaller FAZ, a larger disc and thus larger blind spot (+15%) detected in KS patients might also lead to a size reduction of the visual field.Majority of KS patients received testosterone substitution by application of a transdermal testosterone gel. They were on this medication for at least 2 years. There is no theoretical background within literature how testosterone supplementation could influence the architecture of the eye in the way we describe it. The effect is, assumably, rather attributable to variation in gene dosage inherent to the 47,XXY karyotype.Although the cohorts analysed were relatively small, results revealed a clear phenotype. Nevertheless, further investigations are needed focussing on ocular functionality and the influence of ageing or comorbidities of KS on the aberrant eye condition.15, iris coloboma14 or iris malformation16, cataract16, ocular hypertension18 or diabetic retinopathy19, just to name a few. However, it is difficult to suggest a correlation between these problems and the Klinefelter syndrome, because these problems arise also in many healthy men and women, and the link between these problems and the presence of one or more additional X chromosomes is not known. Moreover, eyes of KS patients participating in our study did not show any obvious ocular irregularities or eye diseases, and we still found the described differences to eyes of healthy controls. We do not see any correlations between a thinner cornea, a thinner retina or a smaller avascular zone to the anecdotic cases of ocular problems in KS patients mentioned above.As mentioned in the Introduction, there are several cases of ocular problems in KS patients, such as choroidal atrophyThe presence of a supernumerary X chromosome is associated with an ocular manifestation in KS patients including a number of morphological and functional features. This should raise awareness towards a possibly higher risk of KS patients to suffer from ocular diseases with the subsequent need for different standards of care for these patients. There is need for future  studies on eye health of KS patients, e.g. on potential reduction of visual acuity, impaired night vision and increased risk for ocular diseases. This chromosomal condition has multifaceted consequences. Physicians, including ophthalmologists, treating KS patients should be aware that KS is a systemic disorder and patients should be examined for possible manifestations.11. Patients presented with testosterone levels within the normal range , either spontaneously (n = 3) or by testosterone substitution (n = 18). The KS patient cohort  was compared to 26 male controls  and 38 female controls  of a similar age with no history of any other systemic or ocular diseases or surgery. In addition to a male control, KS patients were also compared to healthy women to control for the second X chromosome. Although women as well as KS patients inactivate the 2nd X chromosome, some genes escape this X inactivation and are still expressed33. All study participants were of Caucasian origin. Only one eye of each patient was randomly included into the study. Subjects with refractive error > −4 or >  + 4 D spherical equivalent or media opacities that prevented high-quality imaging were excluded. The study followed the tenets of the Declaration of Helsinki and was carried out in accordance with the relevant guidelines and regulations. Before OCTA imaging, participants gave informed consent .For this prospective cohort study, 21 KS patients were recruited at the Centre of Reproductive Medicine and Andrology. Karyotypes were determined as previously described35 using the RTVue XR Avanti with AngioVue  was used to image three times the macula using a 3 × 3 mm² scan  and confocal scanning laser tomography of the optic disc was also performed . In all cases, an experienced examiner manually marked the optic disc margin on the mean topographic image, and the software then automatically calculated the optic disc measurements. Imaging of the cornea was performed by a Scheimpflug tomography . Rotating around the eye, the slit-camera device generates a series of radially oriented images to measure the anterior and posterior corneal surfaces. Based on obtained images, a 3D model of the corneal structure is generated. In the subsequent analysis of the sectional images, tissue boundaries are detected and point clouds are assigned to the various tissue layers. Only Pentacam images of good quality  were included. OCTAcan Fig.  and the can Fig. . DiscrimOnly images with good quality, without motion artefacts and a signal strength index of ≥60 were included. Mean values from three measurements were used for further analyses. The size of the fovea avascular zone  are technically limited because there are no vessels in the FAZ, thus pretending a lower value than if the same level of vascularisation would be present in the whole area of the image. Therefore, in order to get the “real” values of VD  of the vascularized part of the imaged field of the fovea without the FAZ, we converted the given VD values by the following formula:real values of the fovea given in this paper are called only VD values. Segmentation analysis was used to determine thickness of single retinal layers. Automatic segmentation provided by the AngioVue software was checked, and thickness of the single layers was measured manually by an experienced examiner using the built-in measuring tool.Values of VD in the region of the fovea given by the AngioVue device . The general significance level was set to 0.05 .Microsoft Excel 2010 was used for data management. Statistical analyses were performed using GraphPad Prism 6.0 . Data of KS patients were compared with male and female control cohorts using Mann–Whitney The corresponding author had full access to all the data in the study and all authors shared final responsibility for the decision to submit for publication.Supplementary Information


Detailed spectroscopic evolutions in the region of MIR, near-infrared (NIR), visible upconversion (UC) and their corresponding decay times provide insight investigation into the fluorescent mechanism caused by multiphonon relaxation. A possible energy transfer model has also been established. Our results present direct observation and mechanistic investigation of fluorescent evolution in multiphonon relaxation process, which is conductive to design MIR fluorescent materials in the future. To the best of our knowledge, it is the first investigation on MIR fluorescent performance of La2O2S nanocrystals, which may find various applications in many photoelectronic fields.Rare earth doped mid-infrared (MIR) fluorescent sources have been widely investigated due to their various potential applications in the fields of communication, chemical detecting, medical surgery and so forth. However, with emission wavelength extended to MIR, multiphonon relaxation process that strongly quenched the MIR emission is one of the greatest challenges for such practical applications. In our design, we have described a controllable gas-aided annealing strategy to modulate the phase, crystal size, morphology and fluorescent performance of a material simultaneously. Uniform and monodispersed Er Its 2.6~2.7 μm emission from transition of 4I11/2 → 4I13/2 is closed to the O-H vibration peak at about 3 μm and therefore can be strongly absorbed by biological tissues, which is attractive in medical surgery and eye-safe laser radar1415Mid-infrared (MIR), usually defined as the spectral range 2~5 μm, covers the most significant high transparency atmospheric window and numerous “molecular fingerprints” of gases, liquids and solids124562O2S (LOS) and La2O2SO4 (LOSO), which have similar lattice structure, crystallinity, size and morphology.Extending rare earth transitions into MIR, the excited state electrons tend to relax to lower levels nonradiatively by multiphonon relaxation due to the decreasing energy gap. Therefore, MIR transition rate is governed by the maximum phonon energy of host lattice. It is known that crystallinity, doping concentration, dopants’ substitution sites in the host strongly modified their MIR performance1718192O2S and oxysulfate RE2O2SO4 are outstanding luminescent phosphors for applications. RE2O2S with stable thermal and chemical properties, high refractive index (~2.2)−1)23242O2S with optimized Yb3+/Er3+ doping ratio has shown a comparable or even higher quantum yield with respect to the well-known brightest NaYF4 at a reasonable low excitation density2627283+/Yb3+ co-doped La2O2S2O2SO4 also displays a unique fluorescent property activated by rare earth 31323+: Y2O2SO4 offers 3 times stronger emission compared to the its oxide counterpart Eu3+: Y2O3Rare earth doped lanthanide oxysulfide RE2O2S and RE2O2SO4 adopt a similar crystal structure352O2S and RE2O2SO4 in fact is the removal or insertion of oxide anions surround sulfur3+-doped LOS and LOSO nanocrystals by the same hydrothermal precursor with similar crystallinity, size and morphology in order to investigate the impact of multiphonon relaxation on luminescence performance. The effect of gas-aided phase modulation on the morphology and fluorescence performance of the resulted LOS/LOSO nanocrystals was also discussed. We present a detailed spectroscopic investigation on Er3+-doped LOS and LOSO in their MIR, NIR and visible UC emission and corresponding decay times. An intuitive relationship between multiphonon relaxation with fluorescent evolution in the emission region ranging from MIR, NIR to visible UC was established. To the best of our knowledge, it is the first investigation on MIR emission of LOS and LOSO, which have great potential to develop various novel applications in many photoelectronic fields.It is worth noticing that RE3+-doped hydrothermal precursors synthesized with different amount of PVP: (a) 0 g PVP; (b) 1.0 g PVP; (c) 2.0 g PVP and (d) 4.0 g PVP. Most of the precursors are spherical, driven by the minimization of interfacial energy in hydrothermal process. As depicted in 3+-doped precursors obtained with 2.0 g of PVP. With a closer examination, the spherical particles are highly uniform with a smooth surface. EDS spectrum 2+ layer and a layer of anion groups, sulfate (SO4)2− for LOSO (2−) for LOS (2O2)2+, each La atom coordinated with four oxygen anions, which can be considered as a basic unit (LaO4). Then the (LaO4) units connect each other to form a two-dimensional (La2O2)2+ framework by sharing edges. For LOSO, in addition to four oxygen atoms in (La2O2)2+ layer, La atoms are also coordinated with the other two oxygen anions belonging to two different (SO4)2−, leading to a six-coordinated geometry in La-O bonding. For LOS, the layers of (SO4)2− in LOSO are replaced by layers of S2−. La atoms are bonded with three S2− anions to produce a seven-coordinated geometry with four oxygen anions in the (La2O2)2+ plane. The coordination determines the optical spectrum of the compound, which will be discussed in detail later. Such a structural similarity reveals that phase transition between LOSO and LOS is the insertion or removal of oxide anions surround sulfurLOSO and LOS adopt a similar crystal structure35for LOSO  and sulf for LOS . The sta2/CO, respectively. For LOSO, XRD pattern of hydrothermal precursor calcined at 400 °C shows a broad featureless peak, indicating the amorphous or non-crystalline nature of the initial powder. Elevating the annealing temperature to 500~600 °C, the XRD patterns can be indexed to the standard tetragonal structural of LOSO (JPCDS: 16-0501) and no other impurities were observed. Phase transition from tetragonal LOSO to monoclinic is evident in 700 °C, as the diffraction signal located at ~22° split into two adjacent peaks. Further increased the annealing temperature above 800 °C, all the diffraction peaks of LOSO can be indexed to the standard monoclinic LOSO phase (JPCDS: 85-1534), indicating a complete transformation from tetragonal to monoclinic phase. For LOS, the XRD pattern of hydrothermal precursors calcined at 600 °C can be indexed to the tetragonal LOSO. The peaks broadening is due to the poor crystallinity at 600 °C. After the temperature increased to 700~900 °C, the precursors are all converted to the standard hexagonal phase of LOS (JPCDS: 71-2098), and no extra impurities were indexed. Therefore, it is confirmed that LOS is the result of sulfidation of LOSO. Both the diffraction peaks of LOSO and LOS become sharp and intense with annealing temperature increased, indicating a better crystallinity after annealing.et al. reported the oxidation of PVP bonded with Ag starts from 250 °C and ended at ~400 °C, which is similar to our TG dataThe thermal decomposition behavior of the hydrothermal precursor was investigated by thermogravimetric analysis (TG-DSC) conducted from room temperature to 1000 °C with a heating rate of 10 °C/min in air. The TG curves  shows a 3+-doped LOSO in 3+-doped LOS in 3+ ions are successfully doped into LOS particles through our synthetic strategy. Detailed EDS spectrum also illustrated the existence of the above elements in LOS nanocrystals , thus no MIR emission is observed in LOSO, and its total quantum yield is relatively low.here, B and α are material parameters and bonding to the lattice. P is defined as the number of phonons that need to bridge the energy gap ΔE3+ ions, we measured the emission decay times of the 4S3/2, 4F9/2, 4I9/2, 4I11/2 and 4I13/2 states in LOSO and LOS calcined at the same temperature of 900 °C, as depicted in 4I13/2 → 4I15/2, lifetimes of LOS are much longer than that of in LOSO. With increasing WMPR in the host, the radiation transitions in system will compete with more and more nonradiative process, leading to a total transition rate decrease. It should be also notice that the 4I9/2 UC decay curves exhibits an almost immediate decay (0.03 ms) in LOSO compared to that in LOS  between neighboring Er3+ ions are also strongly governed the populations of the 4S3/2 and 4F9/2. The following ETU processes are observed to occur upon 980 nm excitation:One can found that the intensity ratio of the red to green (G/R) in the UC emission in LOS is G/R > 1, while the situation is inverse in LOSO (G/R < 1). In the ESA1 process, photons excited to 4I13/2 to 4I11/2 levels, thereby enhance the red UC emission and also suppress the green one simultaneously.Therefore, increasing the multiphonon relaxation rate can increase the population ratio of the 3+ ions energy levels as well as the possible energy transfer mechanism explaining the Er3+ fluorescence in 5% Er3+-doped LOS and LOSO are shown in 3+ ions are promoted to the 4I11/2 levels through ground state excitation. With relatively low phonon frequency, population of Er3+ ions to higher excited states upon excitation of 980 nm can be realized by the following two processes: (1) direct ESA of 4I11/2 → 4F7/2 or 4I13/2 → 4F9/2; (2) ETU processes as mentioned above, in which an Er3+ ions can be promoted to 4S3/2 or 4I9/2 by consuming the photons in 4I11/2 or 4I13/2, respectively. Considered the relatively short lifetime of the 2I11/2 (1.6~2 ms) compared to the 4I13/2 level (~4 ms), and the depletion by MIR emission at ~2700 nm, it is clear that ESA2 process 4I13/2 → 4F9/2 dominate the ESA process. Therefore, the majority of green UC emission is originated from the ETU process. In general, there is a competition between the various processes. The ETU1 process: 4I13/2, 4I13/2 → 4I15/2, 4I9/2 followed by the 4I9/2 → 4I11/2 multiphonon relaxation is responsible for the main 4I11/2 population except the LD pumped. Since lifetime of the upper level 4I11/2 is shorter than that of 4I13/2 due to the so-called “self-terminating” transition, ETU1 process provide an energy recycle which is benefit for MIR emission: (1) photons with 1530 nm NIR radiation fast deplete to 4I13/2, which suppress the photons accumulation at lower level of MIR emission; (2) populated 4I9/2 state will decay to 4I11/2 through subsequent multiphonon relaxation, leading to an energy recycle for 4I11/2 → 4I13/2. Consider the short-lived 4I9/2 level, the ETU2 process 4I13/2, 4I9/2 → 4I15/2, 4S3/2 is not very efficient. Since ESA2 dominates the ESA process, thus the ETU3 process 4I11/2, 4I11/2 → 4I15/2, 4S3/2 followed by multiphonon relaxation process with the assistant of three or four phonons due to the energy mismatch (~2000 cm−1) is the main population of the green emission in 4F7/2 and 2H11/2/4S3/2 states. The depopulation of the upper state 4I11/2 suppresses the MIR fluorescence and should be prohibited in our future work.The Er−1, the total quantum yield is relatively low and the fluorescent mechanism is rather different. After excitation of 980 nm, the Er3+ ions are promoted to the 4I11/2 state. With a dynamic multiphonon relaxation, the ESA1 process 4I11/2 → 4F7/2 populated the 4I11/2 is not efficient. Therefore, the population to higher state is strongly governed by the ESA2 process, which populated 4F9/2 levels and yielding relatively intense red emission. As mentioned before, ETU3 is the main population process for green UC emission in LOS. Herein, all ETU process is less efficient due to the rapid relaxation of 4I9/2 and 4I11/2, leading to the G/R <1. Photons in LOSO tend to accumulate in the long-lived 4I13/2 state with an intense NIR emission at 1530 nm.For LOSO, with continuous phonon frequency more than 800 cm2/CO atmosphere, respectively. Morphologies of the annealing LOS and LOSO nanocrystals with similar lattice structure and crystallinity maintain good spherical shape with an average diameter of ~300 nm at temperature as high as 900 °C, presenting an excellent thermal stability compared with other nanocrystal counterparts. Effect of annealing on morphology and fluorescent performance in MIR, NIR and visible UC has also been investigated in detailed. Due to the multiphonon relaxation, the visible UC and MIR emission intensity of LOS is much higher than that of in LOSO, while in NIR emission the situation is opposite. A possible energy transfer mechanism has been established to investigate the critical link between the multiphonon relaxation and the interionic interaction of Er3+ dopants. It is expected that the uniform LOS and LOSO nanocrystals with efficient fluorescent emission have potential applications in various fields including communication, chemical detecting, medical surgery and so forth.In conclusion, monodispersed LOS and LOSO nanocrystals with efficient MIR, NIR and visible UC emission have been successfully synthesized through a facile hydrothermal method with a subsequent gas-aided annealing process for the first time. The surfactant PVP plays an important role in control the morphology and size of the as-prepared precursor. Taking the advantage of the structural similarity, the as-prepared precursors convert to LOSO and LOS in air and CS3+-doped LOS and LOSO precursors was as follows. Rare earth oxide La2O3 and Er2O3 were purchased from Aladdin Reagent Co., Ltd., and were dissolved into the corresponding nitrite stock solutions by nitric acid in elevated temperature, respectively. Other chemicals were purchased from Sinopharm Chemical Regent Co., Ltd. All the starting chemicals are analytical grade and used directly without further purification. For the synthesis of precursors, 2.0 g poly(vinylpyrrolidone)  were dissolved thoroughly into 25 mL of ethylene glycol (EG) under vigorous stirring. Then 3.9 mL of La(NO3)3 (0.5 M) and 0.25 mL of Er(NO3)3 (0.2 M) were added dropwise into the above solution. After keeping stirring for another 15 min, 10 mL of ethanol with excess thiourea  was added dropwise into the above mixture and stirred for another 1 h. The clear solution was then transferred into a 50 mL Teflon-line stainless autoclave and heated at 200 °C for 6 h. After naturally cooling to room temperature, the precursors were collected by centrifugation, washed with water and ethanol twice, respectively. Finally, the precursors were dried in atmosphere at 80 °C overnight.The synthesis of 5% Er2/CO, respectively. LOSO were calcined at 700–900 °C for 2 h in air with a heating rate of 3 °C/min. In order to reduce oxygen in atmosphere, LOS were calcined with a facile gas-aided sulfidation treatment, using CS2 and CO mixed gas as the sulfurization agents to replace H2S or N2/S which are toxic and normally easy to pollute the atmosphere furnace. In a typical procedure, 16 g sulfur (S) powder was mixed with excess activated carbon (C) in an corundum crucible sealed by borax (Na2B4O7·10 H2O) and pre-calcined at 800 °C to produce CS2/CO, which will be absorbed in vacancies within the activated C powder. Later on, the precursors were sealed in the above pre-calcined mixture and then heat at 700~900 °C for 2 h with a heating rate of 3 °C/min to obtain LOS nanocrystals.LOSO and LOS nanocrystals were synthesized by calcination of the precursor in the atmosphere of air and CS3+: LOS/LOSO. Raman spectra were collected by a Raman spectrometer  upon excitation of 532 nm laser. All the measurements were performed at room temperature.The thermal analysis including thermogravimetry (TG) and differential scanning calorimetry (DSC) for the hydrothermal precursor powder was performed in a simultaneous thermal analyzer  under air flow with a heating rate of 10 °C/min. The X-ray diffraction (XRD) patterns were collected on an X’Pert PRO X-ray diffractometer  with Cu Kα radiation (λ = 0.15418 nm). The morphologies of as-prepared precursors and resulted LOS/LOSO were performed by a Nova NanoSEM403 field emission-scanning electron microscopy  with an accelerating voltage of 10 kV. Transmission electron microscopic (TEM) images, high-resolution TEM (HRTEM), selected area electron diffraction (SAED), high-angle annular dark-field scanning transmission electron microscopy (HAADF STEM) images and elemental mappings were investigated using HRTEM 2100 F  equipped with energy-dispersive X-ray spectrometer (EDS). The MIR emission spectra were recorded on an OMNI5015i spectrometer  with the excitation of a 980 nm laser diode . The corresponding MIR fluorescence decay times were also performed on the OMNI5015i spectrometer  equipped with a TDS 3012B digital oscilloscope  and a 980 nm pulsed LD . The visible UC and NIR fluorescent spectra were obtained with an iHR 320 spectrometer  equipped with a 980 nm LD  as excitation source. The iHR 320 spectrometer combined with the TDS 3012B digital oscilloscope  and pulsed 808/980 nm LDs  were also employed to measure the corresponding visible UC and NIR luminescence lifetimes of ErHow to cite this article: Pan, Q. et al. Regulating Mid-infrared to Visible Fluorescence in Monodispersed Er3+-doped La2O2S (La2O2SO4) Nanocrystals by Phase Modulation. Sci. Rep.6, 37141; doi: 10.1038/srep37141 (2016).Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.


PLOS Computational Biology launched its ‘Topic Pages’ project as a way to help fill important gaps in Wikipedia’s coverage of computational biology content and to credit authors for their contributions. Topic Pages are written in the style of a Wikipedia article and are openly and publicly peer reviewed on the PLOS Wiki before being published in our PLOS journals, with a second, editable version posted to Wikipedia.Back in March 2012, PLOS Computational Biology has published 11 Topic Pages covering a good range of subjects, from the Hypercycle to Approximate Bayesian Computation. The published articles have been widely viewed on Wikipedia as well as in the journal and well received by the community.Six years on, PLOS Computational Biology Topic Pages. We are looking for topics in computational biology that are of interest to our readership, the broader scientific community, and the public at large and that are not yet covered or insufficiently covered  in Wikipedia. Last year, PLOS Genetics joined the Topic Pages initiative, as detailed in this blog post.We are welcoming submissions for further Wikidata, the community-curated database connecting concepts covered in any Wikipedia article with the Semantic Web [Wikibase. This creates the need to formalize data models: How should concepts like a disease outbreak, a cell-cycle checkpoint, a sequencer, biomineralization, or a functional magnetic resonance imaging (fMRI) data set be modelled in Wikidata or Wikibase? Conversely, what workflows allow us to collect information about such concepts in Wikidata, to interlink it with related information, to validate it, and to keep it up to date? Or, how can the data from Wikidata be explored or put to use in other contexts relevant to computational biology? We are working on establishing the editorial workflows to handle such Wikidata-focused Topic Pages and would welcome submissions to test these waters. For some inspiration, we suggest taking a look at Wikidata-based tools for browsing microbial genomes [We are also exploring how the Topic Pages approach could be extended to include ntic Web . For ins genomes , scholar genomes , or soft genomes .here. If you’ve noticed a gap in Wikipedia’s coverage of particular computational biology topics, we want to hear from you! Please send ideas for Topic Pages to ploscompbiol@plos.org.The Author Guidelines for Wikipedia-focused Topic Pages are available Read on to find out more about how Topic Pages work from authors Szymon Wasik, Natalia Szostak, and Christophe Dessimoz, who describe their experiences of the editorial process and the lives of their articles post-publication.PLOS Computational Biology has a ‘Topic Pages’ project that encourages authors to write Wikipedia articles on computational biology-related topics. As we are Wikipedia enthusiasts and like the spirit of sharing knowledge, we thought that the effort we had put into researching literature on the hypercycle during our project could be well used to prepare a ‘Hypercycle’ Topic Page [During work on one of our recent projects , myself pic Page .PLOS Computational Biology Topic Pages editor Daniel Mietchen in adapting the text to Wikipedia standards. When the article was ready for review, it went through a rigorous evaluation process by excellent researchers. We very much enjoyed the open peer-review and revision process. Thanks to the reviewers, the peer-review process was more like a discussion than a set of criticisms that is often prepared by referees. After being accepted by PLOS Computational Biology, the editors seamlessly transferred the article to Wikipedia. All of these efforts paid off, as after publishing the Hypercycle Wikipedia article in April 2017, the viewership of its content doubled . To be accepted for this section, we had to pass a strict review process by experienced Wikipedia editors. This process helped us to increase the quality of the article even more, primarily by adjusting the style and references to Wikipedia standards. When the page was finally promoted on 2 May 2016, it was visited by over 12,000 people in a single day, becoming the third most popular ‘Did you know …’ article in May  or even no coverage at all . Access statistics  indicateFamously, Wikipedia articles can be updated by any reader. Since publication, our two articles were updated 126 and 34 times. Overall, these changes were minor—mainly spelling and formatting improvements. In my experience, this is less than what a typical peer review would require! I don't think this is because our articles are timeless, but rather because for our topics, the domain experts are scientists, and most scientists are still not used to contributing to Wikipedia.For the research community, the impact of our two Topic Pages can be gauged, admittedly crudely, by bibliometrics. According to Google Scholar, the number of citations are 204 and 57. These solid figures suggest that the articles have been useful.Thus, our two Topic Pages have fulfilled their purpose both for Wikipedia and for the scientific community and as a result proved very gratifying for us.The editorial process itself was great. Our editor, Daniel Mietchen, helped tremendously to bring the article up to Wikipedia's standards. And in true Wikipedian spirit, he made many edits on the manuscript directly. Likewise, the open, wiki-based peer-review process felt more constructive and straightforward than the standard model, in which communication between reviewers and authors is channelled through the editor.In summary, I am a fan of the Topic Page format. If your domain of expertise is poorly covered on Wikipedia, consider contributing one! Particularly if you are a student or an early career researcher, publishing a Topic Page can be a great opportunity to publish a high-impact paper and to develop important writing skills by producing an accessible, jargon-free Wikipedia article. For a more detailed account of our experience as Topic Page authors and additional thoughts on the (complicated) relationship between academia and Wikipedia, you can read the blog post that I wrote a few years ago .


Parkinson's disease (PD) is the second most frequent neurodegenerative disorder worldwide. The depletion of dopamine in the nigro-striatal pathway is a main pathological hallmark that requires continuous and focal restoration. Since dopamine does not cross the digestive mucosa or the blood brain barrier, its lipophilic precursor L-dopa has been employed and remains the pivotal oral medication. However, after 5-7 years of L-dopa, many pharmacokinetic drawbacks contribute to the occurrence of severe motor and non-motor complications (i.e. under and overdoses) . Indeed A viable optimal therapeutic regime would be to continuously compensate the deficit in dopamine in order to prevent oscillations in neurotransmitter concentration . A contiDe Yebenes et al.  previousHowever, both preclinical and clinical reports also highlight two overriding problems that prevented further development; (i) occurrence of tachyphylaxia and (ii) oxidation of dopamine causing enhanced dopamine metabolism and oxidative stress. Indeed, PD patients from previous studies received dopamine prepared aerobically (O-dopamine) and at the same dose throughout a 24 hours cycle. Prior experience obtained from the use of an apomorphine pump and duodopa® has identified the need to differentiate between diurnal and nocturnal minimum efficient dose in order to avoid worsening motor fluctuations .Recently, the authors have overcome these challenges . Indeed,In addition, greater advances in programmable pumps now minimize tachyphylaxia by allowing administration of a lower effective dopamine dose in accordance with the circadian cycle. In a chronic rat model using 6-OHDA-lesioning, continuous circadian i.c.v injection of A-dopamine (16h/day) over 30 days improved motor activity  without occurrence of tachyphylaxia. This safety profile was highly favorable since A-dopamine did not induce dyskinesia or behavioral dopaminergic sensitization associated with dyskinesia as observed with peripheral L-dopa treatment (6 mg/kg twice daily). Conversely, a reduced number of apomorphine-induced rotations were observed with A-dopamine administration. Neither L-dopa or A-dopamine had supplementary deleterious effects on the remaining 10% dopaminergic neurons after ipsilateral 6-OHDA injection. Highest doses of A-dopamine may even have had a positive impact. No overall harmful effects could be attributed to body weight changes and no anatomopathological alteration of heart, liver, pancreas, spleen, kidney, spinal cord, eye, and brain were observed.Similar to L-dopa treatment in previous clinical and preclinical studies, inconsistencies are reported in the use of dopamine, whereby high doses are described as neurotoxic but sub-toxic concentrations have neuroprotective and neurotrophic effects. We confirm that the positive impact of dopamine on dopaminergic neurons of the nigro-striatal pathways was predominantly dependent on dose, but the oxidation state of dopamine is also paramount .In summary, far from being deleterious, we observe that when dopamine levels and oxidative state are harnessed it can be beneficial to neuron survival. Minimizing dopamine administrative dose, focusing delivery location and restricting the oxidative states all had a positive impact on the nigro-striatal pathways. Long-term i.c.v of A-dopamine using a circadian cycle also dramatically reduced the detrimental side effects of the current therapeutic regime of L-dopa (i.e. L-dopa related complications with dyskinesia). The study demonstrated that continuous circadian i.c.v. administration of dopamine close to the striatum is feasible, efficient and safe in mouse and rat models of PD, supporting clinical development of this strategy to be revisited in PD patients with L-dopa related complications with dyskinesia .


CT). Similarly, stress imaging by myocardial perfusion scintigraphy (MPS) provides vital information. To date, the diagnostic performance of integrated CCTA assessment versus integrated MPS assessment for diagnosis of vessel-specific ischemia remains underexplored.Coronary computed tomography angiography (CCTA) allows for non-invasive assessment of obstructive coronary artery disease (CAD) beyond measures of stenosis severity alone. This assessment includes atherosclerotic plaque characteristics (APCs) and calculation of fractional flow reserve (FFR) from CCTA , but without known CAD. All participants will undergo CCTA, MPS, ICA and FFR. FFR will be performed for lesions identified at the time of ICA to be ≥40 and <90 % stenosis, or those clinically indicated for evaluation. Study analyses will focus on diagnostic performance of CCTA versus MPS against invasive FFR reference standard. An integrated stenosis-APC-FFRCREDENCE will determine the performance of integrated CCTA metric compared to integrated MPS measure for diagnosis of vessel-specific ischemia. If proven successful, this study may reduce the number of missed diagnoses and help to optimally predict ischemia-causing lesions.NCT02173275. Registered on June 23, 2014. ClinicalTrials.gov, The online version of this article (doi:10.1186/s12872-016-0360-x) contains supplementary material, which is available to authorized users. Coronary revascularization remains a mainstay of treatment for coronary artery disease (CAD), which continues to affect more than 16 million US adults. Functional myocardial ischemia may result from anatomically obstructive CAD and strongly determines prognosis, and thus is useful for guiding decisions of revascularization . InvasivUntil now, for the vast numbers of patients at low or intermediate risk for CAD, numerous non-invasive stress imaging modalities including echocardiography, cardiac magnetic resonance (CMR), and myocardial perfusion scintigraphy (MPS) have served as a mainstay for identifying ischemia by detecting stress-induced regional myocardial perfusion defects, of which the most commonly employed is MPS , 4. At aCT).In the recent past, coronary computed tomography angiography (CCTA) has emerged as a promising non-invasive imaging modality for the diagnosis of anatomically obstructive CAD, with high sensitivity and negative predictive value compared to ICA , 11. AltAPCs assessment by CCTA has demonstrated high agreement with invasive methods of plaque assessment and has shown to improve discrimination of ischemia-causing coronary lesions . These iCT represents a novel non-invasive imaging technique that can evaluate the physiologic significance of CAD and enables the calculation of vessel-specific FFR  , the left circumflex artery [LCx] , and the right coronary artery [RCA] . Patients who undergo percutaneous coronary intervention (PCI) by intracoronary stenting of ≥1 coronary lesions after the ICA and FFR measurements may have repeat measurements of FFR after the completion of stent deployment, as clinically indicated.The CREDENCE study will be performed in 19 investigative sites in USA, Canada, Netherlands, Japan, China, Latvia, Italy, and South Korea . Each center may not enroll more than 40 % of the total number of subjects. The shortest time duration between noninvasive and invasive testing will be at the discretion of the local physician. The maximum time permitted between noninvasive and invasive tests will be 60 days.CT measure determined by CCTA, when compared with perfusion or perfusion–MBF stress imaging testing, against invasive FFR. Stress imaging will also include additional characteristics, as described above, which do not exhibit co-linearity with other variables. CCTA and stress imaging features will be hierarchically evaluated: CCTA will be evaluated by stenosis, then FFRCT, then APCs; while stress imaging will be evaluated by perfusion, then MBF, then ECG features and finally, functional capacity.The primary objective is to determine the diagnostic accuracy of vessel territory-specific ischemia by use of an integrated stenosis-APC-FFRCT; MPS vessel-specific perfusion deficits; and reduced MBF. Another objective is to determine the accuracy of FFRCT “virtual stenting” with a post-PCI FFR value of >0.80 in an effort to assess the correlation between FFRCT “virtual stenting” to post-PCI FFR.The secondary objective is to compare the accuracy of the individual components of the CCTA and MPS measures to detect ischemia by invasive FFR: APC components; FFRThe CREDENCE target population will comprise a large and representative sample of individuals for whom CCTA and MPS testing confer the largest potential benefit; that is, for those with suspected CAD who are being referred for non-emergent clinically indicated ICA based upon an imaging study (either MPS or CCTA). In this regard, CREDENCE will enroll adult individuals who meet the inclusion criteria and none of the exclusion criteria, as detailed in Table CT metric by CCTA, as compared with territory-specific ischemia on perfusion or perfusion-MBF stress imaging, against invasive FFR. Three vessel territories including the LAD, LCx, and RCA will be examined. The non-ischemic vessels will serve as controls to ischemic vessels. An FFR measurement cutoff value of ≤0.80 will be considered as ischemia-causing, and >0.80 as non ischemia-causing.The primary statistical analysis will be diagnostic accuracy of vessel territory-specific ischemia using an integrated APC-FFRCT will be assessed against an invasive FFR standard for diagnosis of lesion-specific ischemia. Direct comparison of an integrated APC-FFRCT metric to a non-invasive gold standard by a composite perfusion, MBF, ECG, and functional capacity metric will then be made.APCs and FFRCoronary vessels from 309 patients (927 vessels) with moderate or severe ischemia by MPS and who undergo ICA will be studied, so as to determine the physiologically most relevant APCs. If there is no ischemia in a vessel, then the angiographically most severe lesion measured by invasive FFR will be chosen for APC assessment. For these vessels, associations of the APC measures will be examined in relation to vessel-based ischemia.APCs within ischemia-causing lesions will be compared with within-subject control lesions. Matched analysis will be performed to predict the likelihood of a vessel being ischemic based on APCs for lesions ; with an ischemic vessel––that possess the angiographically most severe stenosis and is measured by invasive FFR––matched to one of the remaining arteries .Moreover, additional ischemic:nonischemic vessel combinations will be considered. For any patient with one ischemic vessel, an analysis will be performed using a 1:2 case:control match to compare results with the 1:1 matched analysis. For individuals with two ischemic vessels, a 2:1 case:control match will be performed for each ischemic vessel to the same non-ischemic control vessel, and then comparing these results with the 1:1 matched analysis.CT and invasive FFR will be examined for these vessels, both as dichotomous (≤ versus >0.80) and continuous (ranging from 0 to 1) variables. In addition, the diagnostic performance of FFRCT to invasive FFR will be tested by measures of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).In individuals who experience ischemia, coronary lesions from 309 patients will be studied, and ischemic vessels will be identified by invasive FFR. The region within the same coronary vessel will be identified distal to the most angiographically obstructive stenosis on the CCTA image that was measured by FFR. The agreement between measured FFRCT for ischemic vessels will be compared with within-subject controls. Matched analysis will be performed to predict the likelihood of a vessel to be ischemic based on FFRCT for lesions matched 1:1 within a person. Within-subject matched comparisons will be performed as discussed earlier for the APCs.FFRCT values using information derived from (A) and (B). Multivariate mixed-effects logistic regression analyses will be conducted with APC-FFRCT measures as a predictor of ischemia. A backward stepwise selection method will be used so that only significant variables at p < 0.05 level will be included in the final model. Since these analyses are on a per-vessel basis, a random effects model will be used to account for within-patient clustering. Finally, a summary APC-FFRCT metric as a predictor of ischemia, accounting for the weighted contribution of APCs and FFRCT, will be obtained. This summary APC-FFRCT metric will be tested for its ability to diagnose vessel-based ischemia in a validation cohort of 309 patients who will also undergo CCTA, MPS, ICA, and FFR.An integrated CCTA metric will then be developed that will represent the most parsimonious set of APCs for improving diagnosis of vessel-specific ischemia. The weighted APC set will be combined to FFRCT metric will be directly compared against MPS for the diagnosis of vessel-specific ischemia, using invasive FFR as a reference standard. This integrated metric will be compared against a combined perfusion-MBF-ECG-functional capacity measure by MPS so as to assure the highest diagnostic performance of both CCTA and MPS in comparison. MBF is anticipated to be most useful in the presence of balanced reduction of perfusion  and thus, is expected to increase specificity when a regional vessel-based territory appears normal by perfusion.In the validation cohort, the integrated APC-FFRCT; MPS vessel-specific perfusion deficits; and reduced MBF. Another analysis will compare the accuracy of FFRCT “virtual stenting” with a post-PCI FFR value of >0.80, and to determine the correlation between the FFRCT “virtual stenting” and post-PCI FFR. For segments that were treated with coronary stent and underwent FFR, the post-PCI FFR value will be measured. On a per-segment analysis, “virtual stenting” will be performed and post-“virtual stent” FFRCT will be predicted. The diagnostic accuracy of FFRCT “virtual stenting” to post-PCI FFR will then be calculated, using a cutoff value of >0.80 to be considered non-ischemic and a successful intervention. Further, the correlation between post-FFRCT “virtual stenting” and post-PCI FFR will be performed using Pearson’s correlation or Spearman’s rank correlation, as appropriate.The secondary statistical analysis will compare the accuracy of the individual components of the CCTA and MPS measures to detect ischemia by invasive FFR: APC components; FFRCT. For a logistic regression of a binary response variable, a sample size of 618 patients is needed for a 90 % power at a 0.05 significance level to detect a 30 % increase in the probability that a vessel manifest ischemia. This change corresponds to an odds ratio of 2.0. The study expects to have 309 patients available that will provide more than sufficient sample for variation in the estimated parameters for sample size. To ensure statistical validity, a post hoc power analysis will be run and the actual power achieved by the analysis will be reported.A total of 618 participants will be enrolled in this study. The sample size determination of the primary endpoint was based upon a sequential derivation-validation design for APCs and FFRAll CCTA scans will be performed with single- or dual source CCTA scanners with a minimum of 64 detector rows. Detector row width will be ≤0.75 mm. At a minimum, single-head power injectors allowing fast injection rates of 4–7 mL/s will be required. Laboratories will follow local CCTA scanning protocols as long as they are consistent with quality standards defined by the Society of Cardiovascular Computed Tomography (SCCT) guidelines . CCTA in2 within or adjacent to the lumen that can be discriminated from surrounding pericardial tissue, epicardial fat, or lumen; and identified in ≥2 planes. Stenoses will be graded in accordance with the SCCT segmental 5-point scale: 0 %; 1–24 %; 25–49 %, 50–69 %, and 70–100 % [CT analyses will be performed using the already-acquired CCTA data set. CCTA core lab readers and automated software will perform interpretation of APCs. APCs will be studied by multiplanar reconstructions (MPR) and cross-sections using optimal phases, and by automated software with manual correction, with segments classified by an 18-segment SCCT model [CCTA images will be transmitted to independent masked readers at the CCTA Core Laboratory, who will use dedicated 3-dimensional workstations to evaluate the CCTA images. The 18-segment SCCT model of the coronary tree will be used for the coronary evaluation . Coronar70–100 % . Plaque CT model .Given their association to myocardial ischemia in prior studies, six coronary APCs will be selected and will include 1) low attenuation plaque (LAP); 2) positive remodeling (PR); 3) mixed plaque (MP); 4) plaque burden (PB); 5) minimal luminal area (MLA); and 6) transluminal attenuation gradient (TAG) , 17, 22.Briefly, a Hounsfield unit (HU) <30 will signify LAP, as this threshold exhibits the best performance compared to intravascular ultrasound (IVUS) . A remodCT will be performed by applying a computational fluid dynamics (CFD) approach to typically-acquired CCTA scans for calculation of coronary artery pressure and flow by HeartFlow, Inc. . More detailed information regarding FFRCT and virtual stenting is provided in the online supplementary material, Additional file FFRMPS will be performed by a variety of methods, including PET, SPECT, or CMR. Standard acquisition and analysis protocols will be agreed on for each technique covering patient preparation, cardiovascular stress, administration of radiopharmaceutical or contrast medium, image acquisition and quality control, image processing and interpretation. These procedures will be based on available international guidelines , 26.As such, all MPS studies in this investigation will employ PET when possible. Briefly, dynamic MPS will be performed at rest and during vasodilator stress by 13 N-ammonia (13-NH3) or rubidium-82 (Rb-82) PET using a high-resolution PET/CT scanner, in accordance with societal guidelines . Data wiFor MPS, perfusion in each of the 17 segments will be classified as normal, mild reduction, moderate reduction, severe reduction, or absent perfusion, and the segmental scores were summed for the stress and rest images. An inducible perfusion abnormality will be defined as a summed segmental difference score between stress and rest images ≥2, either from a score ≥1 in ≥2 contiguous segments, or ≥2 in ≥1 segment. Scarring will be defined similarly from the summed segmental rest score. For wall motion abnormalities (WMA), segmental myocardial wall motion will be scored at rest and during stress as normal, hypokinetic, akinetic, or dyskinetic. Inducible ischemia will be defined as an increase in segmental wall motion score ≥1 from rest to stress in ≥2 contiguous segments. Scarring will be defined similarly from the resting wall motion score . The angPatients will undergo diagnostic ICA in accordance with usual clinical indications and by imaging standards set forth by the American College of Cardiology/Society for Cardiac Angiography and Interventions . FurtherCT, and FFR, accurate alignment of CCTA and ICA must be performed. An integration process will be performed in a masked fashion by a study investigator not responsible for CCTA, FFRCT, or MPS evaluation in order to identify the location of a lesion by CCTA that corresponds to the location where the distal pressure sensor of the wire is located at the time of FFR. The latter integration approach will ensure complete masking of the interpretation of CCTA APCs, FFRCT, and ICA and FFR results. On this model, the cardiologist will demarcate the location of the FFR wire, and will refer the model to investigators responsible for interpretation of the CCTA APCs and FFRCT.For suitable comparison of CCTA APCs, FFRThis study will be coordinated by the Dalio Institute of Cardiovascular Imaging Clinical and Data Coordinating Center (DICI CDCC). The DICI CDCC will be responsible for the processing and quality control of the data. The study protocol will be approved at each participating center by the local institutional review board. Completed electronic case report forms (eCRFs) will be entered by trained site personnel, and will be transmitted to a central data repository at the DCC. At regular intervals, all data will be transferred from electronic case report form (REDCAP) to SAS for statistical summarization, data description, and data analysis. Further cross-checking of the data will be performed in SAS.Site qualification will be issued by the DICI CDCC for each modality before subject enrollment. Before beginning enrollment, eligible sites will be qualified by the imaging Core Laboratories based on site surveys and on successful transfer of one or more complete datasets with sufficient image quality and completeness for each modality. During the study, technical quality assessment of image and test acquisition will be accomplished on all studies by central repository research technicians trained by the CDCC. This ongoing review will ensure the adequate quality and completeness of datasets.CT for diagnosis of vessel-specific ischemia. An integrated APC-FFRCT metric by CCTA will then be directly compared to a perfusion-MBF-ECG-functional capacity metric by MPS for diagnosis of vessel-specific ischemia. As such, we hypothesize that an integrated assessment by CCTA will be superior to an integrated assessment by MPS for the diagnosis of vessel-specific ischemia.The CREDENCE study aims to integrate the anatomic and physiologic information derived from CCTA for the precise identification of ischemia-causing coronary lesions, and to compare this measure against an integrated metric for MPS. To date, no non-invasive imaging modality has been routinely capable of a “one-stop shop,” wherein anatomic identification of stenoses and physiologic determination of ischemia are derived from a single test, thus resulting in layered testing and increased complexity and cost of clinical care. Specifically, this study will assess the performance of anatomic APCs by CCTA and physiologic FFRPrior studies have established that MPS is capable of determining the severity and extent of myocardial ischemia with high performance at a per-patient level, and that MPS evaluation is augmented by MBF, ECG, and functional capacity findings , 6. NeveCCTA has demonstrated high performance for diagnosis of obstructive CAD compared to ICA, and predicts adverse prognosis . In the CT for diagnosing coronary ischemia has been reported in several studies [CT demonstrated per-vessel accuracy, sensitivity, specificity, PPV, and NPV for ischemia-causing lesions of 84.3 %, 87.9 %, 82.2 %, 73.9 %, 92.2 %, respectively [CT data matched closely with invasively measured FFR [The PROMISE trial demonstrated equivalent outcomes between functional imaging by multiple modalities, including PET, and anatomic evaluation of stenosis severity by CCTA . The CRE studies , 41, 42.ectively . FurtherCT. The aversion to incorporate APC findings may originate from the fact that APC quantification is time-intensive with per-patient evaluation taking 8–10 h for comprehensive APC evaluation. This study will facilitate widespread applicability by assessing co-linearity of APCs to develop the most parsimonious set of APCs that offers the greatest diagnostic value; and validate the diagnostic utility of the APCs in a separate cohort of individuals. We have ensured that APC measures will be accurate by several safeguards. We will use images only from CCTA scanners with 64-rows or more, the threshold for adequate coronary imaging by CCTA. Further, APCs will be interpreted at a state-of-the-art laboratory by ≥2 readers with inter- and intra-observer assessment for a 20 % of CCTAs for assurances of reliability. Similarly, this study will assess FFRCT, referenced against both invasive FFR and non-invasive stress test “gold” standards. Furthermore, this study will perform APC and FFRCT evaluation with automated software that will facilitate time-efficient evaluation of both APCs and FFRCT.To date, however, clinical reporting of CCTA has been limited to stenosis severity, with relative neglect of APCs and unavailability of FFRSimilar to CCTA, we will perform a comprehensive assessment of MPS. By a dedicated and blinded core laboratory, we will examine factors beyond regional myocardial perfusion, and will include imaging high-risk features of CAD , as well as high-risk ECG features . Functional capacity and MBF will also be assessed.If proven successful and the superiority of a combined anatomic-physiologic approach is shown, this trial will provide the rationale in developing and establishing a novel diagnostic paradigm that not only identifies patients who manifest ischemia, but also specify ischemia-causing coronary lesions that may be more accurate than conventional stress imaging. If the strategies are equivalent, there will still be information gain in determining the most efficient means to determine lesion-specific ischemia by CCTA and MPS. The results of this approach may reduce the number of missed diagnoses and help to optimally predict ischemia-causing lesions, considering the fact that millions of patients are tested for CAD each year in the US alone. Further, this novel diagnostic paradigm may help promote avoidance of unnecessary invasive procedures and procedure-related complications in the future, and allow for improved clinical decision-making to identify patients who are versus who are not eligible for coronary revascularization. Finally, the proposed trial will potentially reduce downstream care related to these invasive procedures as well as the cost burden, and directly impacts annual healthcare savings.The CREDENCE study aims to fill many gaps in knowledge and is distinctive from other prior studies in determining which coronary vessels can be non-invasively determined as manifesting ischemia. By comparing an integrated CCTA measure directly against an integrated measure for MPS, this study will provide unavailable comparative effectiveness data for CCTA and stress testing for diagnosis of lesion-specific ischemia. Moreover, the proposed trial will potentially provide improved patient care and may directly impact clinical practice by reducing rates of unnecessary invasive procedures as well as health care costs.Additional file 1:Online supplementary material. (DOCX 23 kb)


The identification of vulnerable coronary artery atherosclerotic plaques offers the prospect of either localized or systematic therapeutic targeting in order to prevent myocardial infarction. Molecular imaging of atherosclerosis adds to morphological imaging by focusing on the immunobiology hidden in and behind the endothelium and therefore may be able to improve the identification of prospective culprit lesions. Our focus has been on identifying arterial accumulation of oxidized low-density lipoprotein (oxLDL) by exploiting advances in knowledge of vascular pathobiology. Here, we reflect on our work developing near-infrared fluorescence imaging of oxLDL using LO1, a monoclonal autoantibody generated in our laboratory. We detail progress to date and discuss our vision on taking the work through the early translational pipeline toward a multitargeted approach in imaging rupture-prone atherosclerotic plaques. Ultimately, molecular imaging of coronary arteries should be able to assess the regional risk that is specific to a lesion, which can then be used in concert with global risk factors to personalize the therapeutic strategy for patients in a way that goes beyond generalized population-based therapies. The ultimate goal of NIRF molecular targeting is to integrate specific multi-agent biological information with morphological imaging obtained by existing catheter-based technologies , thereby providing a much needed extra dimension for improving the prediction of individual plaque progression and instability.11Significant advances have already been achieved toward the molecular imaging of atherosclerosis.13 When combined with CT, FMT has revolutionized the ease with which molecular targets may be studied, offering a nonradioactive near equivalent to single-photon emission CT and positron emission tomography.14Fluorescence molecular tomography (FMT) is a powerful NIRF preclinical modality that allows simultaneous quantitative molecular imaging in small animals of one or more tracers labeled with dyes operating in distinct near infra-red spectra.16 Imaging of oxLDL in atherosclerosis has already been reported in preclinical ex vivo studies using anti-oxLDL antibodies conjugated to single-photon emitting isotopes,18 and also in vivo with anti-oxLDL-labeled MR contrast agents.20 As yet, we are the only group to report quantitative optical molecular imaging of oxLDL in atherosclerosis in conjunction with other molecular probes.9Oxidized LDL (oxLDL) is a prime target for the molecular imaging of atherosclerosis, not only because it is instrumental in plaque pathobiology but also because its presence may reflect plaque vulnerability.21 We labeled LO1 with the NIRF dye VivoTag-S 750 (and designated this LO1-750), and this specifically reacted with determinants in the necrotic core in human coronary lesions ex vivo.9 Injection of LO1-750 into high-fat (HF)-fed atherosclerotic −/−Ldlr mice led to specific focal localization within the aortic arch and its branches, as detected by FMT combined with micro-CT. Ex vivo confocal microscopy confirmed LO1-750 subendothelial localization at sites of atherosclerosis, in the vicinity of macrophages. When compared with an NIRF reporter of metalloprotease (MMP) activity (MMPSense-645-FAST), both probes produced statistically significant increases in NIRF signal in the −/−Ldlr model in relation to duration of HF diet, with a better target to background ratio (TBR) for LO1-750 . The ability of LO1-750 to quantify atherosclerotic load was further tested in a progression study in the −/−Ldlr model. LO1-750 clearly distinguished between a group fed a HF diet for 42 weeks and a group fed for just 30 weeks. We also studied a middle group that was fed for 30 weeks with a HF diet, and low fat diet for 12 further weeks, and found a correlation trend  between all groups. MMPSense was also able to distinguish between the 2 feeding extremes of the experiment but had a lower correlation trend, indicating that the middle group was not as clearly distinguished as with LO1. The differential identification of the middle group by LO1 is consistent with reporting on the accumulation of the antigen it identifies in plaque, namely, oxLDL. MMPSense, however, tracks MMP activity, and stopping the pro-inflammatory stimulus from the HF diet “turned off” the progression of the MMP signal in the intermediate group. In due course, it may therefore be possible to use both agents simultaneously to distinguish patients between plaque inflammation  and plaque progression . For example, it may be that a particular treatment reduces inflammation (and MMP activity) and the risk of plaque rupture in the short term but fails to halt the buildup of oxLDL (and LO1 reactivity) and clinical manifestations in the longer term.Our laboratory isolated and characterized LO1, a spontaneously arising IgG3k germ line encoded mouse natural monoclonal autoantibody. It was selected for reacting with copper-oxidized LDL in vitro and subsequently found to recognize LDL conjugated with malondialdehyde. LO1 was shown to bind antigen in atherosclerosis by in vitro staining of both mouse and human tissues.2224 The imaging of intravenously (IV) injected LO1-750 with 2-D NIRF in the live animal was suboptimal and did not reflect the whole area identified later with ex vivo fluorescence reflectance imaging. This was likely due to a high LO1-750 background signal remaining in blood, as well as suboptimal tissue penetration in the rabbit, despite imaging being undertaken 21 hours postinjection. Interestingly, using ex vivo intravascular 2-D NIRF imaging, with the aorta flushed completely empty of blood and perfused with saline, we did clearly demonstrate that IV injected LO1-750 could be detected in the diseased area identified on IVUS with a signal to noise ratio of 86.4 and a TBR of 4.8. This was confirmed by matching whole aorta fluorescence reflectance imaging ex vivo with the lesional areas identified by LO1 intravascularly. Importantly, we also demonstrated that the LO1-750 signal was different to the autofluorescence detected in the FITC channel. Furthermore, ex vivo fluorescence microscopy studies of freshly frozen sections showed a pattern of staining in the rabbit atherosclerosis model similar to that seen in LO1-750-injected mice.9As a proof of concept that NIRF imaging with LO1 is applicable to a catheter-based approach, we undertook pilot studies in the laboratory of our collaborator Farouc Jaffer at Harvard Medical School using a 2-D NIRF system combined with IVUS. This system has been successfully used to image balloon injury and stent-induced inflammation in a HF-fed rabbit model.9 Moreover, our initial pilot data in vivo in mice show that LO1-Fab-Cys targets atherosclerotic lesions in −/−Ldlr mice in a similar manner to LO1 native IgG.9Although LO1 has shown great promise in targeting oxLDL within plaques in mouse and rabbit experimental models and in vitro in human, there are obvious problems in using a native mouse IgG clinically. These include suboptimal pharmacokinetics, Fc-related effector function, and immunogenicity, all of which can be improved by creating recombinant molecular derivatives of the parent antibody. With this in mind, we have successfully sequenced and cloned the LO1 VH and VL chain regions, allowing us to molecularly express the antibody in different formats. As a start, we have created a molecularly expressed human chimeric LO1 Fab construct (human CH/CL and LO1 VH/VL) with a cysteine tag (for labeling) and shown that its function resembles that of LO1 in vitro.To further improve our construct, fragments such as single-chain variable fragment and diabodies will be explored to achieve the optimal avidity, penetrance, and background clearance. However, it must be noted that due to the chimeric nature of LO1-Fab, repeated administrations may elicit a human antimouse immune response and thus more fully humanized constructs will also be generated.Bringing an NIRF molecular imaging tool into interventional cardiology will hopefully not only help management in the cardiac catheter laboratory but also provide a platform for the application of anti-oxLDL antibodies and other agents for therapeutic “pay load” delivery. We envisage the development of oxLDL targeting to go hand-in-hand with other targets toward a multipronged approach for the targeting of rupture prone plaques in atherosclerosis, which is still one of the biggest causes of mortality and morbidity in the world.