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Lipase is one of the promising biocatalyst in field of Enzymatic Biodiesel production. Screening of lipase producing bacteria and its media optimization facilitates enhanced lipase production. Considering the advantages of enzymatic biodiesel production using lipases the objective of present work was to isolate lipase producing bacteria and its media optimization. Bacterial strain were isolated from oil rich sample showing maximum zone of hydrolysis on TBA Media was selected and identified as Lysinibacillus macroides FS1 by 16SrDNA gene sequence analysis. Lipase production was carried out in production media and lipase activity of 3.1U/ ml was assayed by titrimetric method. Various media parameters were optimized and maximal lipase activity of 16.75U/ml were observed at 48 hr of incubation in optimized media with Honge oil as inducer, Galactose as carbon source , Ammonium Chloride and Beef extract as source of nitrogen, pH 7 and 37oC temperature with agitation speed of 120 rpm. Under optimized condition 5.4 fold increases in the lipase activity than innate activity was observed. 50.74% yield was observed with specific activity of 21.25U/mg after purification with 30% ammonium sulphate. Purified lipase was stable in presence of methanol at 37°C. Results obtained shows that Lipase from Lysinibacillus macroides FS1 was promising biocatalyst for Biodiesel production.

Biodiesel a fatty acid alkyl esteris one of the promising biofuel and a clean energy source as an alternative to petroleum-based diesel fuels. The Enzymatic transesterification reaction is influenced by many factors such as amount of biocatalyst, molar ratio of oil to alcohol, temperature, pH, rpm, time etc. Effective variables for transesterification may vary based on the type of feedstock and catalyst used, therefore it is essential to optimise the process suitable for each type of feedstock to achieve higher yield of biodiesel. The statistically-based Plackett-Burman experimental design was adopted in this study to identify effective factors for transesterification reaction of Pongamiapinnata seed oil using immobilized lipase. The factors used in the present study for Plackett-Burman design are molar ratio, amount of immobilized lipase, temperature, time, pH, agitation and water content. The result showed that among seven variables, pH (p-value0.003), agitation speed(p-value 0.024) and amount of immobilized lipase(p-value 0.041) having p

In the present study, four surface-active ionic liquids (SAILs) having different head groups (phosphonium, pyridinium, pyrrolidinium, and imidazolium) but the same hydrophobic tail length and same ...

Surface active ionic liquids (SAILs) are a subclass of ionic liquids (ILs), having an amphiphilic character that is surplus to the unique physiochemical properties inherited from the basic ILs. The...

International audience; The abatement of toluene was studied in a sequential adsorption-plasma catalysis (APC) process. Within this process, Hopcalite was used as bifunctional material: as adsorbent (storage stage) and as catalyst via the oxidation of adsorbed toluene (discharge stage). It was observed that the desorption and oxidation activity of the adsorbed toluene was significantly affected the process variables. In addition, the adsorption time influenced the CO2 selectivity and CO2 yield by changing the interaction between the catalyst and the plasma generated species. At least four APC sequences were performed for each examined condition suggesting that Hopcalite is very stable under plasma exposure during all the sequences. Consequently, these results could contribute to advance the plasma–catalyst system with an optimal VOC oxidation efficiency. The catalytic activity, amount of toluene adsorbed, amount of toluene desorbed and product formation have been quantified by FT-IR. Moreover, the catalyst was characterized by XRD, H2-TPR, N2 adsorption–desorption analysis and XPS. Hopcalite shows a good CO2 selectivity and CO2 yield when the APC process is performed with an adsorption time of 20 min and a plasma treatment with a discharge power of 46 W which leads to a low energy cost of 11.6 kWh·m−3 and energy yields of toluene and CO2 of 0.18 (±0.01) g·kWh−1 and 0.48 (±0.06) g·kWh−1 respectively.; La dépollution du toluène a été étudiée dans un processus séquentiel d'adsorption et de catalyse par plasma (APC). Dans ce procédé, l'hopcalite a été utilisée comme matériau bifonctionnel : comme adsorbant (étape de stockage) et comme catalyseur via l'oxydation du toluène adsorbé (étape de décharge). Il a été observé que l'activité de désorption et d'oxydation du toluène adsorbé était significativement affectée par les variables du procédé. En outre, le temps d'adsorption influence la sélectivité et le rendement du CO2 en modifiant l'interaction entre le catalyseur et les espèces générées par le plasma. Au moins quatre séquences APC ont été réalisées pour chaque condition examinée, suggérant que l'Hopcalite est très stable sous exposition au plasma pendant toutes les séquences. Par conséquent, ces résultats peuvent contribuer à améliorer les systèmes plasma-catalyseur pour une efficacité optimale d'oxydation des COV. L'activité catalytique, la quantité de toluène adsorbée, la quantité de toluène désorbée et la formation de produits ont été quantifiées par FT-IR. De plus, le catalyseur a été caractérisé par XRD, H2-TPR, analyse d'adsorption-désorption de N2 et XPS. L'hopcalite montre une bonne sélectivité et un bon rendement en CO2 lorsque le processus APC est réalisé avec un temps d'adsorption de 20 min et un traitement plasma avec une puissance de décharge de 46 W, ce qui conduit à un faible coût énergétique de 11,6 kWh-m-3 et à des rendements énergétiques du toluène et du CO2 de 0,18 (±0,01) g-kWh-1 et 0,48 (±0,06) g-kWh-1 respectivement.

International audience; A dielectric barrier discharge reactor packed with both Hopcalite & glass beads has been investigated for the total oxidation of toluene adsorbed on Hopcalite. The catalytic activity and selectivity through the possible formation of by-products during the NTP discharge for the abatement of irreversibly adsorbed toluene have been investi- gated by FT-IR and mass spectrometer. The regeneration of the used Hopcalite by NTP discharge has been established by (i) determining the amount of toluene adsorbed on NTP regenerated Hopcalite, (ii) investigating the catalytic activity of NTP regenerated Hopcalite and (iii) comparing the bulk and surface properties of the fresh calcined and NTP regenerated Hopcalite. The ratio of amount of irreversibly adsorbed toluene to that of the total amount of adsorbed toluene adsorbed is similar for the fresh calcined and NTP (I) regenerated Hopcalite. The catalytic activity of the NTP (I) regenerated Hopcalite is slightly enhanced when compared to that of the fresh calcined Hopcalite. Although the first NTP treatment induces partial transformation of Hopcalite into Mn3O4 with no detected related CuOx and reduces specific surface area by a factor of 2, the toluene adsorption capacity remains less affected. A plausible reaction scheme for toluene decomposition in Hopcalite PBDBD reactor is proposed.; Un réacteur à décharge à barrière diélectrique rempli de Hopcalite et de billes de verre a été étudié pour l'oxydation totale du toluène adsorbé sur Hopcalite. L'activité catalytique et la sélectivité par la formation possible de sous-produits pendant la décharge du NTP pour la réduction du toluène adsorbé de manière irréversible ont été étudiées par FT-IR et spectromètre de masse. La régénération de l'hopcalite usagée par les décharges du NTP a été réalisée (i) en déterminant la quantité de toluène adsorbé sur l'hopcalite régénérée par le NTP, (ii) en étudiant l'activité catalytique de l'hopcalite régénérée par le NTP et (iii) en comparant les propriétés de masse et de surface de l'hopcalite fraîchement calcinée et de l'hopcalite régénérée par le NTP. Le rapport entre la quantité de toluène adsorbé de manière irréversible et la quantité totale de toluène adsorbé est similaire pour l'hopcalite fraîchement calcinée et l'hopcalite régénérée par le NTP (I). L'activité catalytique de l'hopcalite régénérée par le NTP (I) est légèrement améliorée par rapport à celle de l'hopcalite fraîchement calcinée. Bien que le premier traitement NTP induise une transformation partielle de l'Hopcalite en Mn3O4 sans détection de CuOx apparenté et réduise la surface spécifique d'un facteur 2, la capacité d'adsorption du toluène reste moins affectée. Un schéma de réaction plausible pour la décomposition du toluène dans le réacteur PBDBD d'Hopcalite est proposé.

A novel strategy for toluene abatement was investigated using a sequential adsorption-regeneration process. Commercial Hopcalite (CuMn2Ox, Purelyst101MD), Ceria nanorods, and UiO-66-SO3H, a metal&ndash, organic framework (MOF), were selected for this study. Toluene was first adsorbed on the material and a mild thermal activation was performed afterwards in order to oxidize toluene into CO2 and H2O. The materials were characterized by XRD, N2 adsorption-desorption analysis, H2-TPR and TGA/DSC. The best dynamic toluene adsorption capacity was observed for UiO-66-SO3H due to its hierarchical porosity and high specific surface area. However, in terms of balance between storage and catalytic properties, Hopcalite stands out from others owing to its superior textural/chemical properties promoting irreversible toluene adsorption and outstanding redox properties, allowing a high activity and CO2 selectivity in toluene oxidation. The high conversion of toluene into CO2 which easily desorbs from the surface during heating treatment shows that the sequential adsorption-catalytic thermal oxidation can encompass a classical oxidation process in terms of efficiency, CO2 yield, and energy-cost saving, providing that the bifunctional material displays a good stability in repetitive working conditions.

In the present study, a chemical formulation containing a surface-active ionic liquid (SAIL; tributylhexadecylphosphonium bromide) and a nonionic surfactant (TERGITOL 15-S-9) has been prepared. The composition of the mixed micelle and the interaction parameter between the SAIL and nonionic surfactant at varying concentrations were evaluated by Rubingh theory. The most optimal formulation was then screened through phase behavior tests to determine optimal salinity for the crude/brine/chemical formulation system. The optimal salinity for the oil/water/surfactant system was found to be as high as 9.28 wt %. Dynamic light scattering (DLS) studies and small-angle neutron scattering (SANS) experiments have been performed to provide further insight into the size and structure of the micelles formed by the SAIL and nonionic surfactant, respectively. Traditional laboratory-scale oil displacement experiments were performed to study the effectiveness of the optimized chemical formulation in recovering oil during the...

A large number of matured oil reservoirs still have ample quantity of oil trapped in the pores of the reservoir rock. The quest of a reliable tertiary oil recovery process has opened opportunities for chemical enhanced oil recovery processes. Most of the conventional chemicals used in this method lose their efficacy under high salinity conditions of oil reservoirs. In the present work, synergism in reducing interfacial tension between crude oil and aqueous phase has been investigated, between a mixture of long chain imidazolium ionic liquid and a nonionic surfactant. The reservoir fluid has been modelled as a system containing crude oil/kerosene and surfactant brine. Phase behaviour studies of this system at varying salinities have been studied. Formation of a distinct and stable TYPE III microemulsion at ultra-high salinities has been observed. Presence of middle phase microemulsion at very high salinities indicated ultralow interfacial tensions thereby making the mixed surfactant formulation suitable enough to be used in reservoirs having high salinity of formation brine. Characterization of this middle phase microemulsion was carried out using Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), Polarised optical microscopy (POM) and Dynamic light scattering (DLS) techniques. Time required for the modelled reservoir fluid to coalesce into a stable middle phase microemulsion was characterised using Turbiscan. Subsequently, flooding experiments with only ionic liquid (C16mimBr) and mixed system containing ionic liquid (C16mimBr) + nonionic surfactant (Tergitol 15-S-9) at high salinity conditions were performed. The results showed that during surfactant flooding with C16mimBr alone, the amount of oil recovered was 3.7% of the original oil in place whereas for C16mimBr + nonionic surfactant mixture, percentage of oil recovered was 9.79% of the original oil in place.

The hierarchical H/BEA zeolites were prepared by postsynthesis treatment. The portion of the parent H/BEA zeolite was treated with aqueous 0.1 M NaOH solution with different alkali volume to H/BEA zeolite weight (5, 10, 30,150, and 300 mL/g) ratios. The physicochemical properties of samples were evaluated by powder X-ray diffraction, Pyridine Fourier transform infrared spectroscopy, NH3 temperature programme desorption, Nitrogen adsorption/desorption isotherms, and magic angle spinning nuclear magnetic resonance spectroscopy. The catalytic performance of various catalysts was investigated in solvent free acetalization of glycerol with formaldehyde. Among all the catalysts, a hierarchical H/BEA prepared by treating H/BEA with 5 mL aqueous 0.1 M NaOH solution per gram of H/BEA exhibited the highest specific surface area and high acidity. This optimal hierarchical H/BEA5 catalyst has shown an excellent catalytic activity with glycerol conversion of 78% and 1,3 dioxalane selectivity of 85% under mild operating parameters than reported. H/BEA5 was found to be highly stable and recyclable. The acetalization of glycerol with formaldehyde follows first order reversible using PseudoHomogeneous model. In present study, the activation energy for this reaction is found to be 46.95 KJmol−1 which is lower than reported. © 2017 American Institute of Chemical Engineers Environ Prog, 2017

Enhanced oil recovery is a tertiary method for recovering oil trapped in porous rock of the reservoir. This oil becomes trapped in porous media because of capillary forces. The reduction of these forces by surfactants is an important aspect of enhanced oil recovery. The development of ionic liquid−based surfactants has gained significant interest in their use as cationic surfactants in analytical methods and separations. In the current study, functionality of long chain imidazolium ionic liquids as surfactants have been investigated by measuring, dynamic interfacial tension of water/oil system and their ability to reduce IFT under harsh conditions of salinity and temperature. In the present study, an advantage of 1-hexadecyl-3-methyl imidazolium bromide (C16mimBr) over traditional cationic surfactant (CTAB) has been highlighted. The efficiency of both (C16mimBr & CTAB) in recovering additional oil when used in an EOR process has been found out by conducting lab-scale core flooding experiments. Also, small Poly (dimethylsiloxane), (PDMS) microchannels have been prepared and moduled as oil filled porous structures in the reservoir. Microscopic images of surfactant solutions flowing through these channels have been recorded to find out whether they form emulsions while flowing. The experiments revealed that C16mimBr is more efficient in reducing interfacial tension between water/oil system and thus recovering more entrapped oil than traditional cationic surfactant CTAB. The results obtained here reflect high interfacial activity, high oil solubility due to the formation of emulsions and stability under harsh reservoir conditions for the IL in consideration.

A new class of surface active ionic liquids (SAIL) have been reported to be a greener alternative to the conventional surfactants in enhanced oil recovery (EOR). These SAILs work efficiently under harsh salinity conditions encountered in the reservoir thereby recovering more additional oil during the tertiary oil recovery process. Adsorption mechanism of SAILs on different rock surface is however, not yet reported in the literature. This article highlights adsorption mechanism of three cationic SAILs having different headgroups, viz., imidazolium, pyridinium, pyrrolidinium, on different rock surfaces (crushed natural carbonate rock and crushed sandstone rock). All the SAILs studied here however had the same tail length and same anion (Br−) attached to it. XRD and XPS characterization techniques reveal that the crushed natural carbonate rock contains a substantial amount of silica, thus rendering it a slight negative charge. Static adsorption tests show that the retention efficiency on the natural carbonate type of rock for all the SAILs was lower than the conventional cationic surfactant, CTAB. The adsorption data obtained thereby was examined using four different adsorption isotherm models (Langmuir, Freundlich, Redlich-Peterson, and Sips). Results suggest that Sips adsorption isotherm model can satisfactorily estimate the adsorption of all the surface active agents on the natural carbonate rock. Factors like mineralogical composition of rock surface, presence of divalents, temperature, and structure of surfactants strongly affect the amount of surfactant adsorbed on reservoir rock. In order to evaluate the simultaneous effect all these factors as well as their interdependence on the retention capability of the three SAILs, a design of experiments approach has been employed further in this study. Statistical analysis of the data obtained after performing the full factorial experiments reveal that at high salinity, imidazoluim based SAIL show minimal adsorption on crushed natural carbonate rock at higher temperature. In general, at a given ionic strength, with increasing temperature as the amount of divalent in the aqueous solution increases, the amount of SAIL adsorbed on both the rock types decreases. Electrostatic attraction is the basic mechanism in governing adsorption of SAILs on the two types of rock surfaces. Results presented in this work can be used for EOR schemes.

The hierarchical K/LTL zeolites prepared by post-synthesis modification with aqueous 1.5 M KOH solution by varying alkali volume to K/LTL zeolite (10⿿70 ml/g) ratios, were examined in Knoevenagel condensation. The physico-chemical properties of the catalysts were thoroughly evaluated by PXRD, FTIR, ICP, CO 2 -TPD, XPS, N 2 adsorption/desorption and 29 Si and 27 Al MAS-NMR. Among all the samples, hierarchical K/LTL prepared by treating K/LTL with 50 ml aqueous 1.5 M KOH solution per gram of K/LTL displayed about 1.5 fold higher catalytic activity as compared to parent K/LTL, presumably because of combined effect of enhanced basicity and molecular diffusion through pore channels.

TiO2–SiO2 mesoporous composite photocatalysts with different proportions (in wt%) of TiO2 and SiO2 (TiO2–SiO2 = 20:80, 40:60, 60:40, 80:20 and 100:0) were prepared by loading TiO2 on as-synthesized Si–MCM-41 using sol–gel method. The physicochemical properties of composites were investigated by powder X-ray diffraction, N2 adsorption–desorption measurements, transmission electron microscopy and UV–Vis diffuse reflectance spectroscopy. It is revealed that the titanium species are dispersed as TiO2 having interaction with the surface of the support. Even at high TiO2 loading, the mesostructural feature of MCM-41 was found to be intact without pore blockages. The change in morphology of TiO2 particle was observed with increase in TiO2 loading which may be due to different environment for the growth of TiO2. The photocatalytic evaluation of composites was carried out in production of hydrogen by water splitting. Among the prepared samples, mesoporous composite containing 60 % TiO2 (MTi60) has shown the best results (0.08805 mmol of H2/h/g of TiO2) compared to other composite photocatalysts. The catalytic performance of this sample was further enhanced (~8 times) after loading 1 % Pt in water splitting (0.70161 mmol of H2/h/g of TiO2). 1 % Pt loaded on pure TiO2 (MTi100) showed hydrogen evolution of the magnitude 0.26 mmol of H2/h/g of TiO2. TiO2–SiO2 mesoporous composite photocatalyst showed much higher activity (~1.9 times) than amorphous silica-embedded titania catalyst having same composition.

Levulinic acid (LA) is considered as a renewable platform chemical and can be used for the synthesis of variety of important fuels and chemicals. In particular, its esterification with ethanol produces ethyl levulinate (EL) would be green process, as it can be used as diesel miscible biofuel (DMB), preventing global warming by decreasing atmospheric CO 2 . This study explores the use of modified H-ZSM-5 by desilication viz.; DH-ZSM-5 and dodecatungstophosphoric acid (DTPA) loaded on DH-ZSM-5 for esterification of LA with ethanol aiming to EL. Different degree of desilication of H-ZSM-5 was performed by using aq. NaOH (0.2–1.5 M) at 338 K for 30 min and then DTPA was loaded on these desilicated H-ZSM-5 (DH-ZSM-5) support. H-ZSM-5, DH-ZSM-5 and DTPA on these DH-ZSM-5 samples were characterized by powder X-ray diffraction (XRD), N 2 adsorption–desorption, pyridine chemisorbed IR spectroscopy, Temperature Programmed Ammonia Desorption (TPAD). The increase in conversion of levulinic acid was observed from 28% to 94% with increase of DTPA loading from 0% to 15%. The increased LA conversion may be due to increase in total acidity from 43.14% to 84.31%. The use of DH-ZSM-5 as support for deposition of DTPA may be reported for the first time. The present work also extended to optimize process parameters such as DTPA loading on DH-ZSM-5, catalyst to LA ratio, LA to ethanol molar ratio, speed of agitation, particle size reaction temperature and catalyst reusability. Kinetic study based on pseudo-homogeneous (P-H) model is also presented. The experimental results follow second order kinetics.

The surface properties of a poly(dimethylsiloxane) elastomer have been modified by reacting an allyl amide functional perfluorinated ether (PFE) to the siloxane network by a hydrosilation reaction. Examination of the surface by contact angle and X-ray photoelectron spectroscopy revealed that the perfluorinated ether migrates to the surface of the polymer, thus reducing its surface energy from 22 to about 8 mJ/m2 without affecting its bulk material properties. The resultant surface however exhibits higher contact angle hysteresis than that seen with the PFE-free elastomer. These results indicate that the higher energy amide functionalities of the perfluorinted ether are available for interfacial interaction, even though they are buried below the PFE layer. This study demonstrates that a high-energy group can be pulled to the free surface of a polymer by the driving forces of the lower energy groups segregating to the surface. The high-energy groups are available for further chemical interactions when the s...

Dual-effects of adsorption and photodegradation over titania, silica embedded titania, silica and commercial Degussa P-25 samples were studied for the decolourization of methylene blue in aqueous medium. Silica embedded titania and silica were prepared using inexpensive polymeric version of ethyl silicate as a source of silica. Catalysts were characterized by X-ray diffraction, scanning electron microscopy, UV-Vis spectroscopy and low temperature (77 K) nitrogen adsorption measurements. Among all the catalysts, silica embedded titania has exhibited faster decolourization of methylene blue solution on account of the enhancement of adsorption followed by degradation. An amount of the catalyst and the initial dye concentration of MB solution were found to influence the decolourization activity. Compared to titania catalyst, silica embedded titania and Degussa P-25 have shown the red shift in their UV-Vis spectrum. The experimental data of the reaction fitted well to the pseudo first order kinetic model. In present studies, the adsorption mechanism for the decolourization of MB solution was found to be applicable for an intra particle diffusion model.

In this study, Taguchi method was used to identify the several factors that may affect the percentage degradation of phenol and p-chlorophenol in wastewater in a UV/H2O2/TiO2 system. The percentage degradation of phenol and p-chlorophenol was greatly influenced by factors such as pH, cycle time and initial concentration of the organic pollutant. By using orthogonal experimental design and analysis technique, the UV/H2O2/TiO2 system performance can be analyzed with more objective conclusion through only a small number of simulation experiments. Analysis of variance (ANOVA) was carried out to identify the significant factors affecting the response and the best possible factor level combination was determined through. Finally, a regression model for percentage degradation of phenol and p-chlorophenol has been developed, as a function of system parameters. It was found that a UV/H2O2/TiO2 system decomposition of the organic pollutant were highly dependent on cycle time followed by pH of aqueous solution. The optimal settings of highest percentage degradation of phenol and p-chlorophenol in wastewater were also determined.

Background Altered serotonergic function is thought to play a role in the pathophysiology of major depressive episodes based upon evidence from neuroimaging, pharmacological, postmortem and genetic studies. It remains unclear, however, whether depressed samples that differ with respect to having shown a unipolar versus a bipolar illness course also would show distinct patterns of abnormalities within the serotonergic system. The current study compared serotonin transporter (5-HTT) binding between unipolar-depressives (MDD), bipolar-depressives (BD) and healthy-controls (HC) to assess whether the abnormalities in 5-HTT binding recently found in depressed subjects with BD extend to depressed subjects with MDD. Methods The 5-HTT binding-potential (BP) measured using positron emission tomography (PET) and [ 11 C]DASB was compared between unmedicated, depressed subjects with MDD ( n = 18) or BD ( n = 18) and HC ( n = 34). Results Relative to the healthy group both MDD and BD groups showed significantly increased 5-HTT BP in the thalamus (24%, 14%, respectively), insula (15%) and striatum (12%). The unipolar-depressives had elevated 5-HTT BP relative to both BD and HC groups in the vicinity of the periaqueductal gray (PAG, 20%, 22%, respectively). The bipolar-depressives had reduced 5-HTT BP relative to both HC and MDD groups in the vicinity of the pontine raphe nuclei. Depression-severity correlated negatively with 5-HTT BP in the thalamus in MDD-subjects. Conclusions The depressed phases of MDD and BD both were associated with elevated 5-HTT binding in the insula, thalamus and striatum, but showed distinct abnormalities in the brainstem. The latter findings conceivably could underlie differences in the patterns of illness symptoms and pharmacological sensitivity observed between MDD and BD.

Background Evidence from neuroimaging post-mortem, and genetic studies suggests that bipolar disorder (BD) is associated with abnormalities of the serotonin-transporter (5-HTT) system. Because of various limitations of these studies, however, it has remained unclear whether 5-HTT binding is abnormal in unmedicated BD-subjects. This study used PET and [11C]DASB, a radioligand that afforded higher sensitivity and specificity for the 5-HTT than previously available radioligands, to compare 5-HTT binding between BD and control subjects. Methods The 5-HTT binding-potential (BP) was assessed in 18 currently-depressed, unmedicated BD-subjects and 37 healthy controls using PET and [11C]DASB. Results In BD, the mean 5-HTT BP was increased in thalamus, dorsal cingulate cortex (DCC), medial prefrontal cortex and insula and decreased in the brainstem at the level of the pontine raphe-nuclei. Anxiety ratings correlated positively with 5-HTT BP in insula and DCC, and BP in these regions was higher in subjects manifesting pathological obsessions and compulsions relative to BD-subjects lacking such symptoms. Subjects with a history of suicide attempts showed reduced 5-HTT binding in the midbrain and increased binding in anterior cingulate cortex versus controls and to BD-subjects without attempts. Conclusions This is the first study to report abnormalities in 5-HTT binding in unmedicated BD-subjects. The direction of abnormality in the brainstem was opposite to that found in the cortex, thalamus, and striatum. Elevated 5-HTT binding in the cortex may be related to anxiety symptoms and syndromes associated with BD.