Electrospinning can be used to create nanofibers from diverse polymers in which also other materials can be embedded. Inclusion of magnetic nanoparticles, for example, results in preparation of magnetic nanofibers which are usually isotropically distributed on the substrate. One method to create a preferred direction is using a spinning cylinder as the substrate, which is not always possible, especially in commercial electrospinning machines. Here, another simple technique to partly align magnetic nanofibers is investigated. Since electrospinning works in a strong electric field and the fibers thus carry charges when landing on the substrate, using partly conductive substrates leads to a current flow through the conductive parts of the substrate which, according to Ampère’s right-hand grip rule, creates a magnetic field around it. We observed that this magnetic field, on the other hand, can partly align magnetic nanofibers perpendicular to the borders of the current flow conductor. We report on the first observations of electrospinning magnetic nanofibers on partly conductive substrates with some of the conductive areas additionally being grounded, resulting in partly oriented magnetic nanofibers. Nanofibers can be produced by electrospinning diverse polymers or polymer blends ,2,3. GenTypically, such nanofiber mats contain arbitrarily oriented nanofibers. For several applications, however, aligning them would be supportive. In the literature, different approaches can be found to reach this goal. Often a high-speed rotating collector is used ,22,23, bEspecially for the case of magnetic nanofibers, a magnetic field-assisted electrospinning process was suggested to create oriented nanofibers ,27,28. AAdding a magnetic field or working with a rotating cylinder, however, is often not possible especially in commercial electrospinning devices with usually high safety standards, impeding modifications of the interior. Here we report for the first time on another possibility to align magnetic nanofibers during electrospinning which can easily be applied in many electrospinning devices. Due to the strong electric field in the spinning chamber, conductive lines applied on an isolating substrate lead to a fiber orientation perpendicular to the borders between conductive and isolating areas. We report on the influence of grounding the conductive lines, spinning duration and other spinning parameters.Nanofiber mats were created by electrospinning in a “Nanospider Lab” , using a wire-based technology. The setup is shown in It should be mentioned that this electrospinning technology is not well-suited to prepare very long nanofibers in the range of several millimeters, as it is possible with the needle-based process ,40,41. DThe spinning parameters for this study were: voltage between the wires 80 kV (with a positive voltage applied to the spinning wire and the other wire behind the substrate being grounded), nozzle diameter 0.9 mm (pure polyacrylonitrile nanofiber mats) or 1.5 mm (magnetic nanofiber mats), carriage speed 100 mm/s, substrate speed 0 mm/s, bottom electrode/substrate distance 240 mm, ground electrode / substrate distance 50 mm, temperature 24–26 °C and relative humidity in the chamber 31%–32%. Spinning was carried out for 10 min if not mentioned differently.3O4 (magnetite) nanoparticles with particle sizes of 50–100 nm  were added by manually stirring the solution for 10 min before dispersion in an ultrasonic bath for 30 min at 35 °C with a frequency of 37 kHz. The polymer:nanoparticle weight ratio was chosen as 1:1.56 which is in the range of a former test series . Investigations of fiber diameters, angular distribution and fast Fourier transform (FFT) evaluations were performed with ImageJ 1.51j8 .Firstly, As visible in It should be mentioned that the finer fibers tend to be not separately visible in the CLSM image, resulting in apparently larger diameters of the nanofibers depicted in the latter.Next, The copper tapes (orange lines) are either aligned perpendicular to the spinning wires  or parallel to it. Electrospinning was performed for 10 min or 5 min with PAN/magnetite or pure PAN.These copper wires, especially when grounded, serve as additional ground electrodes, strongly influencing the electric field. Generally, simulations of the electric field in needleless electrospinning have revealed strong differences of the electric field near the connection line between both electrodes and farther away. Ahmad et al., e.g., showed that for a modified spinning wheel with teeth the highest electric fields were only available in a range of few cm and dropped fast outside this region . ElectriWhile such simulations of the electric field distribution can be found in the literature for diverse nozzle and substrate geometries, similar theoretical investigations of the influence of the charge transfer from electrostatically charged nanofibers onto the ground electrode, or resulting magnetic fields or of moving magnetic fibers inside the electric field of the electrospinning setup are, to the best of our knowledge, not yet available. This paper thus serves as a base for future simulations of these dynamic procedures, pointing out phenomena occurring during electrospinning magnetic nanofibers and allowing for comparing future simulations with the experiment.Next, The photographic images reveal a clear difference between the nanofiber mats electrospun on not grounded and grounded copper tape. On the latter, the nanofibers seem to be strongly concentrated along the borders of the copper tape, and from the macroscopic view, there is an orientation of the dark nanofibers perpendicular to the borders of the copper tape visible.This finding, however, is not supported by the microscopic images c,d. WhilNext, Firstly, it is clearly visible that many more fibers can be found on the grounded tapes than on the others. This could be expected since the electrospinning process works by creating a strong electric field between the high-voltage wire which is coated by the polymer solution and a grounded wire. Here, more grounded wires are created, in this way deforming the electric field and partly taking over this task from the original grounded wire of the machine.Next, many more fibers are visible around the wires in the middle of the spinning area. Generally, this behavior is identical to the effect in the normal electrospinning process, usually resulting in a constant movement of the substrate if a large nanofiber mat with equal thickness along the whole area is desired. Here, however, this effect is much stronger since the grounded electrodes are now directly in the substrate plane, causing the electric field to vary laterally more strongly than in case of the normal grounded wire 50 mm above the substrate plane.Next, Interestingly, especially in case of the not grounded copper tape a, there This finding suggests that in the case of a copper strip aligned perpendicular to the electrospinning wires, the lack of alignment is also due to the large number of nanofibers. Fewer nanofibers deposited on the substrate, due to a shorter spinning time or a position close to the limits of the spinning range, can on the other hand lead to aligned nanofibers.The results of the next experiment with a reduced amount of nanofibers are presented in Apparently, the orientation of the magnetic nanofibers with respect to the borders of the conductive areas is universal as long as not too many magnetic nanofibers are involved, independent from the orientation of the copper tape with respect to the spinning wires and from a possible grounding of the copper tape.The electrospinning process, treated from the electromagnetic perspective, is a very complex and interesting phenomenon, not fully understood till today, and not yet deeply analyzed with the use of basic physical principles. For the technological case applied in the study reported here, we should distinguish between the two main components of the phenomenon; the movements of highly charged fibers before deposition on the substrate, and the discharging effects just after deposition. Moreover, these two situations can be further enhanced by the presence of electrically conductive copper tape, especially for the grounded case.In the first phenomenon, the movement of electrons located in non-conducting fibers, in the moment before deposition, can be treated as electric currents flowing into directions perpendicular to the tape surface. In accordance to Ampère’s law, the current produces closed loops of magnetic field lines lying in-plane at the tape. Such a magnetic field enhances orientation order of ferromagnetic fibers which are deposited in a parallel order.During the second step, when fibers are coupled physically to the tape, especially for the grounded case, the electrons flow from the fibers into the conducting materials, and discharging effects take place, in such a way that electrons from higher electrified fibers flow into places in where there are fewer electrons. Generally, this leads to a current flow along the conductive tapes and correspondingly to magnetic fields circularly surrounding the conductive tapes, i.e., perpendicular to them. In case of grounded copper tapes, the current flows towards the grounded end of the tape; in the case of the non-grounded tapes, only short-distance current flows occur so that the whole wire is homogenously charged. These effects of random local origin are a reason to spatially chaotic distribution of electrospun material, and obviously should dominate for the not-grounded tape, in where the random distribution of fibers is a result of spatially random electric-charge flows on the substrate. Hence, the parallelism of fibers, for the grounded case, is more evident for the case when a copper tape is perpendicular the electrospinning wires which define some electric field anisotropy.Generally, it must be mentioned that the alignment of the nanofibers perpendicular to the grounded copper tapes is much more efficient than the alignment perpendicular to the non-grounded ones. This is especially well visible in After these qualitative examinations, the fiber orientations are finally examined more quantitatively. For this, For the pure PAN nanofiber mat a and theIn addition, Here, the PAN/magnetite nanofiber mat electrospun on a non-conductive substrate shows a clearly isotropic angle distribution b. PAN/maThese first results indicate that in general it is possible to obtain highly oriented magnetic nanofibers by electrospinning on partly conductive areas. Nevertheless, more research is necessary to optimize this process, e.g., by tailoring the polymer:nanoparticle ratio, the spinning parameters—especially the spinning duration, and the geometry of the conductive paths. It can be imagined that a fine network of thin parallel conductive lines may allow for creating fully aligned areas of magnetic nanofibers; an idea which has to be examined in the future.In this paper we report on the influence of a partly conductive substrate on wire-based electrospun magnetic nanofiber mats. Nanofiber diameters were increased by approximately a factor of 2, as compared to pure PAN nanofibers, by the addition of magnetite nanoparticles. We find that independent of the orientation of the conductive paths with respect to the electrospinning wires and a possible grounding of the copper tape, the first magnetic nanofibers are always oriented perpendicular to the borders of the conductive areas. FFT calculations and calculations of fiber angle distributions underline the strong fiber orientation along the borders of conductive areas. Elongated electrospinning, however, results in strong accumulation of the nanofibers in these regions which apparently disturb the magnetic fields responsible for the fiber orientation.In the next experiments, this orientation process will be optimized to gain more highly oriented nanofibers by modifying the solution and spinning parameters as well as the geometry of the conductive paths. In addition, measurements of the magnetic properties will be carried out to investigate the magnetic anisotropy in addition to the optically recognizable fiber alignment.


The previously published structure of the fungal metabolite acremine P is revised by re-evaluation of chemical shift values and NOESY data, and by DFT calculations. Acremonium isolated from both terrestrial or marine sources have been reported to produce meroterpenoids, alkaloids, peptides or oxygenated metabolites [1)  by catalytic hydrogenation under mild conditions  was instrumental in defining the carbon framework and partial relative configuration of acremine P, while the absolute configuration at C-6 was determined by NMR analysis of O-methylmandelate (MPA) ester derivatives. The remaining stereochemical elements were resolved by evaluation of NOESY data, molecular modeling and selected heteronuclear coupling constant values [Fungi from the genus abolites ,3,4,5,6.ites [1)  from a st values .In this communication, we revise the carbon framework of acremine P based on a comparison of calculated and experimental NMR chemical shift data. The predictions of chemical shift values by quantum chemical methods have provided valuable insights into natural product structures, including guiding the choice of diastereomer for structure confirmation by total synthesis ,9,10. Re13C-NMR shifts with a mean absolute error (MAE) of ~1.6 ppm. The calculations involve Boltzmann averaging from a ωB97X-V/6-311+G model using conformer geometries from the ωB97X-D/6-31G* model and chemical shifts from ωB97X-D/6-31G*, but are also empirically corrected to account for the local environment. There was close agreement between the calculated vs. experimental 13C-NMR shift values for acremine Q (3), thereby corroborating the structure and stereochemistry of the metabolite as previously published. For acremine P, originally assigned structure 2, the preliminary computational search for conformers revealed a single dominant conformer, with the closest alternative being upwards of 10 kJ/mol higher in energy and thus not contributing significantly to the equilibrium mixture. As shown in 13C-NMR shift values for acremine P, with deviations of 20.4 ppm for the alkene carbon (C-2) and 23.0 ppm for the hydroxymethine carbon (C-7). Consequently, the published structure for acremine P could not be correct. While deviations of 3 ppm between the experimental and calculated values are considered acceptable, even up to 5–6 ppm for carbonyl groups, a deviation of >10 ppm between experimental and calculated values is diagnostic of an incorrect structure [The structures of acremines P and Q were examined using a combination quantum chemical/empirical approach   that protructure ,14.13C-NMR shift values suggested that the signal at 95.0 ppm (C-7), previously assigned to a secondary alcohol center, was instead associated with an acetal or lactol center. Furthermore, the alkene carbon signals (102.4 and 162.5 ppm) indicated a polarized double bond, likely enolized given the number of oxygen atoms in the molecule. With this information, three candidate structures (4)–(6) (H 5.83 (d) and the signal at ™H 4.15 (s) for the hydroxymethine proton (H-8) each showed HMBC bond correlations to the acetal carbon at 99.0 ppm. In isomer 4, these correspond to three bond correlations, whereas in isomers 5 and 6, the lactol proton and the hydroxymethine proton, respectively, were each four bonds distant from the acetal center. Furthermore, in planar structure 5, an HMBC between the lactol proton and the alkene C-3 at 162.5 ppm would be anticipated.A re-evaluation of the  (4)–(6) , each of3 was considered further with DFT computations undertaken on four diastereomers (4a–4d)   followinJH7–H8 in stereoisomers 4a–4b, respectively. The two stereoisomers  thus fitted the coupling data. It was noted that all four stereoisomers showed a heteronuclear (C4-H8) J value close to 5 Hz, and so these data did not distinguish 4a from 4d. NOe data also supported the choice of stereoisomer, in that from their 3D stereostructures both isomers 4a and 4d were expected to show an nOe between the lactol proton and one only of the two methyl groups; in contrast, isomers 4b and 4c were each expected to show nOes between the lactol proton and both methyl groups. In acremine P, the lactol proton at δH 5.83 shows an nOe to the methyl signal at δH 1.43 for H-11, but not to the methyl signal at δH 1.47  couplings were calculated using the methods of Kutateladze et al. , yieldin δH 1.47 . The cal2) as the sole product, and used this information to specify the absolute configuration at C-6 of acremine P; clearly this information must be in error since the dioxolane ring of the revised structure is incompatible with the tetrahydrofuran ring previously ascribed to acremine P. Nevertheless, we anticipated that acremine P would have the same 6R configuration as its co-metabolite acremine A. In our earlier publication , we repoThe isolation and characterization of acremine P has been previously reported . DetailsIn conclusion, our revision of the structure of acremine P illustrates the valuable role of computational studies in evaluating the structures and stereochemistry of stereochemically complex natural products. At the same time, a single piece of data in the original study, i.e., the suggested conversion of acremine P into acremine A by hydrogenation, compromised the structural study and thereby incorrectly informed the structure determination.


Bridelia micrantha is traditionally used in tropical Africa to treat a wide range of human and animal diseases. The aim of this study was to summarise the research that has been done on the ethnomedicinal uses, phytochemistry and pharmacological properties of B. micrantha so as to understand its importance and potential value in primary healthcare systems. The literature search for information on ethnomedicinal uses and pharmacological activities of B. micrantha was undertaken using databases such as Web of Science, Scopus, Google Scholar, Science Direct, BioMed Central (BMC), PubMed and Springerlink. Other relevant literature sources included books, book chapters, websites, theses, conference papers and other scientific publications. This study showed that B. micrantha is used as herbal medicine in just over half (57.3%) of the countries in tropical Africa where it is indigenous. A total of 54 ethnomedicinal uses of B. micrantha have been recorded with a high degree of consensus on burns, wounds, conjunctivitis, painful eyes, constipation, gastric ulcers, cough, headache, rheumatism, painful joints, dysentery, ethnoveterinary medicine, malaria, sexually transmitted infections, stomach ache, tape worms and diarrhoea. Different plant parts, aqueous and organic extracts exhibited anthelmintic, antimicrobial, anticonvulsant and sedative, antidiabetic, antidiarrhoeal, antinociceptive, antioxidant, antiplasmodial, antischistosomal, hepatoprotective, insecticidal and β-lactamase inhibitory activities. Bridelia micrantha (Hochst.) Baill. is a small to medium sized tree belonging to the family Phyllanthaceae (formerly Euphorbiaceae), commonly known as mitzeerie or coastal golden leaf [Bridelia” was coined in honour of Samuel Elisée Bridel-Brideri (1761–1828), a Swiss-German muscologist [micrantha” means “small-flowered” [Bridelia includes approximately 60–70 species found throughout tropical and subtropical regions of the world, particularly Africa and Asia [Bridelia species are used in traditional medicine throughout the world as an anthelmintic, antiamebic, antianemic, antibacterial, anticonvulsant, antidiabetic, antidiarrhoeal, antiinflammatory, antimalarial, antinociceptive, antiviral, hypoglycemic and for abdominal pain, cardiovascular, gynecological and sexual diseases [B. micrantha are widely used as herbal medicines in tropical Africa [B. micrantha has been identified as one of the few plant species that should be integrated in the domestication process in farming systems in sub-Saharan Africa to support medicinal, nutritional and income security of local communities through household use and marketing of its fresh or dried fruits [B. micrantha is domesticated as a fruit tree in Malawi [B. micrantha is sold as such in the herbal medicine or “muthi” markets in Cameroon [B. micrantha is also an important timber tree species in tropical Africa, and the species is being overexploited as a source of wood for construction, poles, furniture, mortars, spoons and tool handles in Ethiopia [B. micrantha with emphasis on the validation of the ethnopharmacological uses of the species. Results of this review are expected to reveal research challenges and perspectives required to address the knowledge gaps of this important medicinal plant species in tropical Africa.den leaf . The geni 1761–188, a Swisi 1761–188, a Swislowered” . The genand Asia ,4. Severl Africa ,6. B. min Malawi . Due to Cameroon , Malawi Cameroon , NigeriaCameroon  and SoutCameroon . B. micrEthiopia  and KenyB. micrantha and other historical names and synonyms of the species such as Bridelia abyssinica Pax, Bridelia abyssinica Pax var. densiflora Gehrm., Bridelia mildebraedii Gehrm., Bridelia speciosa Mϋell. Arg. var. trichoclada Mϋell. Arg., Bridelia stenocarpa Mϋell. Arg., Bridelia zanzibarensis Vatke & Pax, Candelabria micrantha Hochst. as well as common names such as “Benin ironwood”, “coastal golden leaf”, “mitzeerie” and “Yoruba ironwood” were used as the keywords in searching the major databases including Web of Science, Scopus, Google Scholar, Science Direct, BioMed Central (BMC), PubMed and Springerlink documenting traditional uses, medicinal uses, ethnobotany, ethnomedicinal uses, ethnopharmacology, pharmacology, phytochemistry and therapeutic value of the species. Additional literature, including pre-electronic literature such as scientific articles, conference papers, books, book chapters, dissertations, these and other grey material were sourced from the University of Fort Hare library in South Africa.B. micrantha has been recorded in several countries throughout tropical Africa , stomach ache, tape worms and diarrhoea , followed by Cameroon with 18 uses and six literature records, DRC with 14 uses and three literature records, Tanzania with 12 uses and five literature records, Kenya with 11 uses and six literature records, and Nigeria with nine uses and seven literature records.There is cross-cultural agreement among ethnomedicinal uses of iarrhoea . EthnomeB. micrantha [B. micrantha contain a wide variety of classic nutrients, such as minerals, carbohydrates, polyol , and proteins (B. micrantha fruits (B. micrantha were in the decreasing order of Mg > Ca > Mn > Zn > Fe > Cu > Co > Ni ≈ Cr > Pb. The dietary reference intake (DRI) of some of the chemical elements is shown in Multiple classes of phytochemicals including alkaloids, anthocyanidin, anthraquinones, carbohydrates, cyanogenic glycoside, essential oil, ester, flavonoids, oxalate, phenolic compounds, saponins, sterols, tannins, terpenoids as well as several minerals have been isolated from the bark, fruits, leaves and roots of icrantha ,75,76,77proteins . Severala fruits . ShelembB. micrantha -en-3-ol were isolated from fruits of B. micrantha  value of 400 μg/mL [B. micrantha against S. typhimurium, S. sonnei and S. aureus with ciprofloxacin as a positive control. The MIC50 values ranged from 0.0048 mg/mL to 0.312 mg/mL [B. micrantha against E. coli, Mycobacterium chelonae and S. aureus. The methanolic extract of B. micrantha demonstrated weak activity against E. coli with IC50 values of 64 μg/mL [B. micrantha against E. coli, S. typhi and S. aureus using micro-broth dilution assay. Methanol extract of B. micrantha exhibited a zone of inhibition of 7 to 19 mm against S. aureus and S. typhi respectively [B. micrantha corroborate the traditional uses of the species against bacterial infections such as cough in Cameroon, DRC, Nigeria and Zimbabwe [Samie et al.  evaluaterae-suis . The minrae-suis . Similarrae-suis  evaluatedermidis . Gangouédermidis  evaluate10 mg/mL . Adefuye10 mg/mL  evaluate25 mg/mL . Mabeku 25 mg/mL  evaluate00 μg/mL . In a di00 μg/mL  evaluate12 mg/mL . Traore 12 mg/mL  evaluate64 μg/mL . Douglas64 μg/mL  evaluateectively . These dZimbabwe ,28,32,33Zimbabwe ,40,41, dZimbabwe ,42,43, sZimbabwe ,60,63, sZimbabwe ,48,51,60Zimbabwe ,65 and vZimbabwe ,25,38.B. micrantha using mice model maximal electroshock (MES), strychnine (STR), pentylenetetrazol (PTZ), picrotoxin (PIC), isonicotinic hydrazide acid (INH)-induced convulsions and diazepam-induced sleep in assessing the sedative effects. Results showed that B. micrantha stem bark extracts at the doses of 34 and 67 mg/kg protected 100%, 80%, 80% and 80% of mice from PIC, STR, PTZ and MES-induced seizures, respectively [B. micrantha also delayed the onset to seizures in the INH test. The decoctions of B. micrantha possess sedative and anticonvulsant activities and these results corroborate the use of the species as herbal medicine for epilepsy and insomnia in Cameroon [Bum et al.  evaluateectively . B. micrCameroon .B. micrantha using alloxan-induced diabetic mice in vivo and in vitro. The methanol leaf extract at the dose of 250, 500, and 1500 mg/kg showed remarkable time-dependent decrease in blood glucose level in alloxan-induced diabetic mice. Adika et al. [B. micrantha and glibenclamide (2 mg/kg) were lower than the normal blood glucose level for the groups before the induction of diabetes. Even in its crude form, the effects were comparable to that of glibenclamide, an oral sulfonylurea with proven antidiabetic activity. These findings demonstrate that B. micrantha has antidiabetic effects on experimental model of diabetes in mice and validate its use in Cameroon, Guinea and Nigeria as a traditional medicine for the treatment of diabetes mellitus [Adika et al.  evaluatea et al.  found tha et al.  found thmellitus ,35,36,37B. micrantha against different experimental models of diarrhoea in rats as well as bacteria that cause diarrhoea such as E. coli, Plesiomonas shigelloides, Salmonella virchow and S. dysenteriae and S. flexneri. The methanolic bark extract of B. micrantha demonstrated weak inhibitory activities against P. shigelloides and S. flexneri [Lin et al.  evaluateflexneri . Based oflexneri . All plaflexneri . These fflexneri  corroborflexneri , Camerooflexneri ,32,46, Dflexneri ,22, Gambflexneri , Guinea-flexneri ,48, Kenyflexneri ,60, Nigeflexneri ,41, Soutflexneri ,39,40 anflexneri .B. micrantha against Candida albicans and Candida glabrata using the disc diffusion assay and broth micro-dilution methods. The ethanol extract of stem bark of B. micrantha gave a diameter zone of inhibition of 10 mm against C. glabrata [B. micrantha against Aspergillus fumigatus, C. albicans and Trichophyton rubrum. Traore et al. [50 ≤ 10 μg/mL), good (10 μg/mL < IC50 ≤ 20 μg/mL), moderate (20 μg/mL < IC50 ≤ 40 μg/mL), weak (40 μg/mL < IC50 ≤ 64 μg/mL) and inactive (IC50 ≥ 64 μg/mL). The methanolic extract of B. micrantha demonstrated weak activity against A. fumigatus with IC50 value of 64 μg/mL [B. micrantha against various skin infections in Cameroon [Mabeku et al.  evaluateglabrata . Similarglabrata  evaluatee et al.  used the64 μg/mL . These dCameroon , Kenya [Cameroon  and TanzCameroon .Helicobacter pylori activities of B. micrantha dichloromethane, ethyl acetate, acetone, ethanol, methanol and 40% methanol hydroxide stem bark extracts against Helicobacter pylori using agar-well diffusion method with ciprofloxacin as control. Zone diameters of inhibition ranged from 0 to 18 mm for the extract and 29 to 38 mm for ciprofloxacin. The MIC50 values ranged from 0.312 mg/mL to 0.625 mg/mL [Helicobacter pylori activities of ethyl acetate, acetone, aqueous and methanol extracts of stem bark of B. micrantha against Helicobacter pylori using clarithromycin, metronidazole and amoxicillin as controls. The inhibition zone diameters ranged from 0–23 mm for all the extracts in comparison to 0–35 mm observed for clarithromycin [H. pylori strains (100%) was observed for the acetone extract, followed by ethyl acetate extract at 93.5% and clarithromycin had susceptibility of 58.1% [50 values ranged from 0.0048 to 0.313 mg/mL while the MIC90 values ranged from 0.0048 to 2.5 mg/mL for the acetone and ethyl acetate extracts [Helicobacter pylori activities of ethyl acetate extract of stem bark of B. micrantha against H. pylori with ciprofloxacin as positive control. B. micrantha extracts showed some activity with MIC50 values ranging from 1.25 mg/mL to 5.0 mg/mL [Helicobacter pylori therapies. These findings are significant since bark, leaf and root decoctions of B. micrantha are widely used as traditional remedies for gastric ulcers in Cameroon [Adefuye et al.  evaluate25 mg/mL . Okeleye25 mg/mL  evaluatehromycin . Marked of 58.1% . The MICextracts . Adefuyeextracts  evaluate.0 mg/mL . The ethCameroon , DRC [16Cameroon .B. micrantha against Mycobacterium tuberculosis using a tetrazolium microplate assay to determine the minimum inhibitory concentration (MIC). Acetone extract was active against M. tuberculosis with a MIC value of 25 µg/mL [n-hexane sub-fraction of ethyl acetate fractions from acetone extracts of B. micrantha stem barks using the resazurin microplate assay against M. tuberculosis. The n-hexane fraction showed 20% inhibition of M. tuberculosis H37Ra and almost 35% inhibition of M. tuberculosis isolate resistant to all first-line drugs at 10 μg/mL [M. tuberculosis strain [M. tuberculosis isolate resistant to isoniazid (INH), ethambutol (EMB), streptomycin (STM) and rifampicin (RIF) at a concentration of 50 μg/mL [B. micrantha in traditional medicine for treatment of respiratory systems such as chest complaints and cough in Cameroon [Green et al.  evaluate25 µg/mL . In anot25 µg/mL  evaluate10 μg/mL . The pris strain . The fra50 μg/mL . These p50 μg/mL ,86 serveCameroon ,28,32, DCameroon ,22, NigeCameroon  and ZimbCameroon .B. micrantha stem bark. The antinociceptive effects of B. micrantha extracts at the doses of 50, 100 and 200 mg/kg were investigated using male Wistar rats via acetic acid-induced writhing reflex and tail flick methods and the effects of B. micrantha on thiopentone-induced narcosis was also investigated. The B. micrantha extracts produced a significant dose-dependent decrease in the mean number of abdominal constriction in the acetic acid-induced writhing reflex when compared to the negative control. Both the extract (200 mg/kg) and paracetamol (400 mg/kg) produced 61.85% and 73.08% inhibition of writhing reflex, respectively [B. micrantha and pentazocine (3 mg/kg) caused a significant increase in the pain reaction time (PRT) in treated rats when compared to the negative control group in tail flick method. The pretreatment of the rats with B. micrantha at different doses increased the normal sleeping time of thiopentone from 69.33 ± 7.31 min to an average of 105.33 ± 11.88 min [B. micrantha in the management of pain, for example as remedy for abdomninal pain in DRC and Uganda [Onoja et al.  evaluateectively . B. micr1.88 min . The resd Uganda ,16, epigd Uganda , muscle d Uganda , painfuld Uganda ,39,46,54d Uganda ,24,25,65B. micrantha using the DPPH  and ferric reducing antioxidant power (FRAP) assay methods. The DPPH assay showed 98% antioxidant activity at concentration of 400 µg/mL while FRAP values were 0.016, 0.39, 0.455, 0.601 and 1.382 µM at 10, 50, 100, 200 and 400 µg/mL respectively [B. micrantha using DPPH spectrophotometric assay at the concentration of 400 μg/mL. The ferric reducing antioxidant power showed a significant concentration-dependent increase in the total antioxidant power. Nwaehujor et al. [B. micrantha using the DPPH and FRAP assay methods with ascorbic acid as reference standard. The methanol extracts of B. micrantha leaves gave 98% antioxidant activity at a maximal test concentration of 400 µg/mL while ascorbic acid produced a comparatively reduced percentage value of 79% at the same concentration [B. micrantha leaf extracts produced 1.39 µM at 400 µg/mL but 1000 µg/mL of ascorbic acid had a standard FRAP value of 2.0 µM [B. micrantha stem bark using 2,2-diphenyl-1-picrylhydrazyl (DPPH) photometric assay. B. micrantha extract produced concentration-dependent increase in percentage antioxidant activity in DPPH photometric assay. The B. micrantha extract demonstrated a potent antioxidant activities with 50% inhibitory concentration (IC50) of <25 μg/mL concentration in DPPH photometric assay [B. micrantha has antioxidant potential. Shelembe et al. [B. micrantha using the DPPH stable free radical method using ascorbic acid as control. The IC50 value for the methanol extract of the stem bark of B. micrantha was 150 μg/mL while that of the standard ascorbic acid was 41 μg/mL indicating the high antioxidant potential of the plant, especially the stem bark [−1 with the scavenging ability 85.5% [Nwaehujor and Udeh  evaluateectively . Adika eectively  evaluater et al.  evaluatentration . In the f 2.0 µM . Onoja ef 2.0 µM  evaluateic assay . These re et al.  evaluatetem bark . The scaty 85.5% . These aB. micrantha aqueous, dichloromethane, dichloromethane and methanol (1:1) twig extracts against Plasmodium falciparum using the parasite lactate dehydrogenase (pLDH) assay. B. micrantha dichloromethane and methanol (1:1) extract showed a weak activity with IC50 value of 59.3 µg/mL [B. micrantha methanol leaf extracts against P. falciparum using the lactate dehydrogenase (pLDH) assay. B. micrantha extract showed a weak activity with IC50 value of 158.7 µg/mL [B. micrantha stem bark ethanol extracts against chloroquine-resitant P. falciparum strain using the parasite lactase dehydrogenase method. B. micrantha extracts inhibited malaria parasite by 71.87% growth inhibition rate at 100 µg/mL on P. falciparum strain. Although B. micrantha extracts are characterized by weak antiplasmodial activities [Clarkson et al.  evaluate.3 µg/mL . Similar.3 µg/mL  evaluate.7 µg/mL . Nondo etivities ,91, thestivities , Ivory Ctivities  and Tanztivities ,59.B. micrantha bark on Swiss white mice infected with Schistosoma mansoni with praziquantel as control. There were no significant differences between praziquantel which showed worm reduction percentages of 75.2% against 48.7% and 63.4% demonstrated by hexane and water extracts respectively [B. micrantha extracts were able to protect the mice from schistosomiasis infection.Waiganjo et al.  evaluateectively . These fB. micrantha leaf methanol extracts against human immunodeficiency type 1 reverse transcriptase by assessing inhibition of the RNA dependent DNA polymerase activity by measuring the degree of incorporation of methyl-3H thymidine triphosphate using polyadenylic acid. Ribonuclease H activity was evaluated by measuring the extent of degradation of a radiolabelled RNA in an RNA/DNA hybrid by reverse transcriptase. The methanol extract of the leaves of B. micrantha inhibited the polymerase with IC50 value of 23.5 μg/mL and the ribonuclease H with IC50 value of 18.9 μg/mL [B. micrantha root methanol extracts for activity against HIV-1 reverse transcriptase (RT) and integrase (IN). The n-butanol fraction obtained from the crude methanol extracts of B. micrantha inhibited the RNA-dependent-DNA polymerization (RDDP) activity of HIV-1 RT with an IC50 of 7.3 µg/mL. More pharmacological evaluations are required as B. micrantha is widely used against viral infections such as HIV/AIDs in Kenya [Bessong et al.  evaluate.9 μg/mL . In anot.9 μg/mL  evaluatein Kenya , yellow in Kenya  and otheB. micrantha on paracetamol induced liver damage in Wistar rats through measuring alanine aminotransaminase (ALT), aspartate aminotransferase (AST), alkaline phosphate (ALP), bilirubin and total protein. B. micrantha extract significantly decreased the level of AST in the rats given PCM, reduced ALP and total bilirubin while total protein was significantly increased [B. micrantha had better hepatoprotective effects on the Wistar rats than the known silymarin especially at 300 mg/kg. Therefore, B. micrantha has the ability to help in the regeneration of damaged hepatic cells and can be useful in the treatment and management of hepatic diseases.Nwaehujor and Udeh  evaluatencreased . Nwaehujncreased  also fouB. micrantha against Podagrica uniforma (Jacoby) and Nisotra dilecta (Jacoby) insect pests of okra (Abelmoschus esculentus (L.) Moench) with synthetic insecticide cypermethrin as control. Yield parameters such as number of fruits and fruit weight were collected on insect population before treatment application and three days after spraying of insecticides at 28, 35, 42, 56 days after planting (DAP). There were no significant differences between mean number of P. uniforma and N. dilecta counted on okra plants after 56 DAP which were 0.80 ± 0.10 and 0.47 ± 0.17 for B. micrantha and cypermethrin respectively. There were no significant differences in mean yield of okra fruits after application of B. micrantha and cypermethrin which stood at 0.93 ± 0.3 and 2.20 ± 0.23 respectively [B. micrantha extracts exhibited effectiveness in reducing the insect population and improved A. esculentus fruit yield compared to cypermethrin. Therefore, B. micrantha crude extracts could be explored as promising insecticidal agents to provide valuable alternatives to chemical control of insect infestation on A. esculentus [B. micrantha has insecticidal properties corroborating traditional use of the bark and leaf decoction as insecticide in Tanzania [Adesina et al.  evaluateTanzania .B. micrantha by assessing the inhibition activities (over 90%) against four classes of β-lactamases, namely TEM-1, OXA-10, IMP-1 and P99. B. micrantha extracts had strong inhibition activities of 99.2% and 92.0% against OXA-10 and P99 respectively. After elimination of tannins, the extracts of B. micrantha were tested further for anti-β-lactamase activities with OXA-10 demonstrating potent inhibitory activity with 50% inhibitory concentration (IC50) value of 0.02 mg/mL [B. micrantha will provide useful leads in the search and development of β-lactamase inhibitors.Gangoué-Piéboji et al.  evaluate02 mg/mL . Further50 value) at 95% confidence interval was calculated with the brine shrimp lethality assay for each plant methanol extract. B. micrantha leaf extract showed the least LC50 value of >9.0 × 106 µg/mL [B. micrantha using brine shrimp toxicity with dimethyl sulphoxide (DMSO) and seawater as negative controls. B. micrantha ethanol root extract was found to be mildly toxic with concentration killing fifty percent of the larvae (LC50) of 30 μg/mL [B. micrantha using the OECD guideline, the up-and-down-procedure by orally dosing five male Wistar rats with 2000 mg/kg of B. micrantha and observing the rats for 48 h for signs of toxicity and death. Oral administration of the B. micrantha extract was well tolerated at the dose of 2000 mg/kg and no death and clinical signs of toxicity were observed [B. micrantha using brine shrimp lethality test for the determination of LC50 and the water extract with LC50 of 77 μg/mL was deemed toxic.Ajaiyeoba et al.  reported06 µg/mL  evaluate30 μg/mL . Onoja e30 μg/mL  assessedobserved . Similarobserved  evaluateB. micrantha using human adenocarcinoma cells of the cervix (HeLa), human breast cells (MCF-12A), lymphocytes (both resting and stimulated) and primary porcine hepatocytes. Steenkamp et al. [B. micrantha extracts using the luminescent bacteria Vibrio fischerii and the vertebrate Poecilia reticulata (guppy). The 50% inhibition of proliferation (IC50) of B. micrantha in HeLa cells was 8.9 μg/mL, IC50 was 24.2 μg/mL in MCF-12A cells and the positive control, cisplatin had IC50 value of 1.14 μg/mL and 0.21 μg/mL for the HeLa and MCF-12A cells respectively. Toxicity was found to be concentration dependent when HeLa and MCF-12A cells were exposed to B. micrantha extracts. B. micrantha extracts resulted in 100% mortality of the guppies [B. micrantha leaves and stem bark using the resazurin reduction assay against CCRF-CEM leukemia cell line. The dichloromethane and methanol extract of B. micrantha leaves and stem bark displayed cytotoxicity towards leukemia CCRF-CEM cells with IC50 value of 9.43 µg/mL and 23.5 µg/mL respectively [B. micrantha extracts are cytotoxic and possess acute systemic toxicity. According to Verdcourt and Trump [B. micrantha is poisonous as death of a patient has been reported, four hours after the ingestion of a cough mixture made from B. micrantha herbal concoction in Kenya.Steenkamp et al.  evaluatep et al.  also det guppies . Similar guppies  evaluateectively . These snd Trump , B. micrB. micrantha as herbal medicine throughout its distribution range, the documented phytochemistry and pharmacological properties call for detailed pharmacokinetics and clinical research on the species and its pharmaceutical and food products. At the moment there is insufficient evidence to interpret the documented ethnomedicinal uses with specific chemical mechanisms associated with some of the documented pharmacological properties. Future research should identify the bioactive compounds, details of their molecular modes or mechanisms of action, pharmacokinetics and physiological pathways for specific bioactives of B. micrantha. B. micrantha has been categorized as poisonous by Verdcourt and Trump [B. micrantha is used as herbal medicine. Therefore, future research should focus on dosage range that is safe for humans and evaluation of target-organ toxicity.The historical traditional usage of nd Trump , toxicitnd Trump , Moshi end Trump , Omosa end Trump  and Osebnd Trump  appear t


Static‐lattice atomistic simulations, in vacuum and solvent phase, have been recently employed to quantify the “in vitro—in vivo—in silico” performance‐correlation profile of various drug delivery systems and biomaterial scaffolds. The reactional profile of biopolymers was elucidated by exploring the spatial disposition of the molecular components with respect to the formulation conditions and the final release medium. This manuscript provides a brief overview of recently completed and published studies related to molecular tectonics of: (a) the nanoformation and solvation properties of the surfactant‐emulsified polymeric systems; (b) the formation and chemistry of polyelectrolyte complexes; (c) the effect of a plasticizer and/or drug on the physicomechanical properties of biomedical archetypes; (d) the molecular modeling templates to predict stimuli‐ and environmentally esponsive systems; and (e) the polymer‐mucopeptide complexes and intermacromolecular networks. Furthermore, this report provides a detailed account of the role of molecular mechanics energy relationships toward the interpretation and understanding of the mechanisms that control the formation, fabrication, selection, design, performance, complexation, interaction, stereospecificity, and preference of various biopolymeric systems for biomedical applications. Conversely, there are in silico only studies providing the theoretical knowledge of various material archetypes with only few being tested at the in vitro and fewer at the in vivo level. In addition, the computational methods applied in the advanced in silico studies are very expensive and extensive in terms of time and funding.The elucidation of mechanism(s) inherent to the performance of biopolymer‐based complex assemblies presents a significant challenge to pharmaceutical and biomedical scientists around the world with most of the studies 1.1V∑ is related to total steric energy for an optimized structure, Vb corresponds to bond stretching contributions , Vθ denotes the bond angle contributions , Vϕ represents the torsional contribution arising from deviations from optimum dihedral angles, Vij incorporates van der Waals interactions due to nonbonded interatomic distances, Vhb symbolizes hydrogen‐bond energy function, and Vel stands for electrostatic energy.The MMER model for the energy factor in various molecular complexes can be written as:Total, was calculated as the difference between the total potential energy of the complex system (A/B) and the sum of the potential energies of isolated individual molecules , as follows:In addition, the total potential energy deviation, ΔE2surfactant‐evaporation (ESSE) and 2) emulsion‐solvent‐evaporation (ESE). The MMER report of these complex colloidal phases concluded that the presence of a surfactant such as sorbitan monooleate can provide the much needed conditions for the formation of uniform polymeric nanoparticles. In the ESSE paradigm, the presence of surfactant led to an increase in thermodynamic energy at the solvent/particle interface and hence the coagulation and aggregation of the nanosystem was prevented. In addition, the electrostatic and steric repulsions in case of ESSE were in the range of 1,000 and 200 kca/mol, respectively, under solvent phase simulations. Similarly, alginate nanoparticles were prepared using rigidification–gelification approach with or without adding a surfactant: (a) reverse‐emulsion‐cationic‐gelification (RECG) and (b) reverse‐emulsion‐surfactant‐cationic‐gelification (RESCG). In addition to the thermodynamic shielding and repulsions discussed above, the presence of surfactant in RESCG provided a hydrated palisade layer structure which played a major role in crosslinking induced stabilization of the nanosystem termed as—“crosslinking stabilized–stabilized emulsion.” The presence of this hydrated layer increased both the polarizability and refractivity coefficient of the RESCG matrices leading to the formation of a rigidified structure with least probability of colloidal aggregation or flocculation  directly corroborated with the ex vivo internalization findings.The formation and formulation of nano‐based systems can be achieved either through relatively simple self‐assembly (nanoliposomes or nanopeptides) or via complex emulsification‐homogenization (polymeric nanoparticles). In either case, the stabilization of the nanosystem so formed is of utmost importance and can be achieved in several ways such as by using a surfactant, a polymeric stabilizer  or even via crosslinking‐co‐rigidification of the polymeric platform.575, PEG2000, and PEG4000) and were then loaded with insulin as the model bioactive. As explained above, PEG provided the much needed hydrophilicity to the lipophillic PLA matrix and hence nanoformation within the pluronic‐based aqueous phase. Similar to CHOL, the PEG molecules played the space‐filling role and hence led to the stabilization of nonbonding hydrophobic interactions leading the efficient encapsulation of insulin in the nanomatrix. Interestingly, when MMER was applied to study the release of insulin from the nanomatrix, the presence of aqueous phase (with no cosolvent or surfactant present) hydrated the PEG component leading the entry of water into the nanomatrix and hence disturbing the hydrophobic forces thereby releasing the encapsulated bioactive. However, this concept failed in case of low molecular weight PEG‐diacrylate where the drug release was least on weight basis. The MMER conducted for all three variants in aqueous medium concluded that the insulin showed molecular interactions with the functional groups (–COOH and –NH2) present in the polymer matrix. This further confirmed that insulin released from PLA‐PEG575 matrix will be slowest as low molecular weight PEGDA will have more NH2 functional end groups than the higher molecular weight ones.On similar grounds, DSPE‐PEG/DSPC‐based nanoliposomes with cholesterol (CHOL) as the lipidic component were reported earlier. The presence of methoxy‐PEG moiety led to the formation of H‐bonding within the phospholipid complex. However, this still was not sufficient to form a thermodynamically stable nanosystem. As determined by the 3D geometrical conformation and stabilization via molecular modeling, the addition of CHOL provided the much needed space filling properties to the ternary system wherein the van der Waals space of the molecular complex contributed to matrix stabilization. This change in H‐bonding dominated system to hydrophobically stabilized system was further responsible for the self‐assembly of the complex into nanoliposomes (nanoformation) when hydrated in phosphate buffered saline.33. In addition, the molecular dynamics simulation supported the energy stabilization and it was concluded that “the potential energy decreased with an increase in the kinetic energy, obeying the well‐known behavior of high underdamping harmonic oscillator.”Polyelectrolyte complexes, as the name suggests, are complex molecular architectures composed of oppositely charged molecules. As the charged functional groups are “consumed” in the process, the inherent solubility and functionality of the individual molecules are reduced and hence an insoluble but hydrated and swellable matrix is formed.3+ (CHT and HPAAm) and –COO− (PEC and HPAAm) functional groups formed the TPIQ network via structure‐selective binding of saccharidic moieties. The in silico results concluded that the geometrical adjustment of polymeric chains to form the ionic complex is due to the minimization of Coulombic attractions and van der Waals forces. This further confirmed the in vitro controlled release of a highly soluble drug (diphenhydramine) due to matrix curing and formation of a “deforming‐type” matrix.Bawa and coworkers reported a molecular model of a tripolymeric ionic quadrilateral (TPIQ) wherein chitosan and pectin formed the cationic and anionic counterions, respectively. The third polymer employed was a partially hydrolyzed polyacrylamide (HPAAm) which acted as an anionic molecule as well as a cationic molecule in close vicinity of chitosan (CHT) and pectin (PEC), respectively. The molecular modeling simulations presented a van der Waals space overlap and the hydrogen bonding between the interaction molecules confirmed that –NH3+ of mucin and –COO− of pectin chains – overcoming the torsional barriers required for a stable network. It was further established that this interaction is concentration dependent and saturation of functional groups can be achieved by carefully manipulating the biomaterials' quantities.In a very important study, a mucopeptide was employed as an excipient to form a bimolecular complex with pectin. Although there were several earlier reports discussing the interactions of pectin with mucin, the molecular interactions inherent to this complex were not yet known or elucidated. The researchers via MMER established that there might be a possibility of formation of a blend‐co‐complex within this proteo‐saccharide matrix. Although the –COOH functionalities of the molecules lead to steric repulsion and a strained network, this initiated the much needed “neighboring” of the counterions: –NH4Polymeric fibers provide distinctive advantages in terms of size selection and mechanical properties which further define the final biomedical application. For example, nanofibrous mats are widely employed for wound dressing and oral drug delivery, microfibers for sutures, and macrofibers for periodontal diseases. For these fibers to perform optimally mechanically, addition of plasticizers is a common practice and follows the same principles as for the plasticization of polymeric films. However, given the large surface area and fine diameter size of the fibrous systems, the addition of any additives needs to be carefully controlled. For example, in case of electrospun nanofibrous systems, the electrospinning process involves careful selection of polymers and additives which in in turn affect the processing variables. As the final size of the fibers is in the range of nanometers with high surface area, addition of even a small quantity of drug may lead to reassignment of processing variables.2),As opposed to nanofibrous mats, micro‐ and macro‐fibers are fabricated using the extrusion‐gelification technique. The macrofibers in particular are used individually and afford different set of challenges such as holding the fiber using a tweezer  or simply implanting around a tooth for localized periodontal drug delivery. Johnston and coworkers, described crosslinked‐co‐plasticized, drug‐loaded, alginate fibers for localized periodontal drug delivery.Furthering the modeling of plasticizers within polymer matrices, Cooppan and coworkers explained the importance of a solid plasticizer's concentration on the optimal performance of a Eudragit E100‐based memblet system. The MMER obtained from solvent system simulation confirmed that addition of PEG4000 at a very high concentration (60% wt/vol) may lead to formation of charged regions with less solvent accessibility. These charged regions may further distort the electrostatic balance of the polymeric matrix causing repulsion and a strained network. However at 30% wt/vol PEG4000 concentration, the PEG‐enclatherated polymethacrylate system was comparatively more geometrically stabilized with defined viscoelastic regions and consistent drug release profile.54‐stabilized pectin matrix. The matrix provided localized delivery if mesalamine in the colon environment and under the influence of colonic enzymes polygalacturonase and β‐glucosidase. The colonic enzyme fragments employed in the study were generated via deduction of information corresponding to the active catalytic amino acid sequences for human acid β‐glucosidase and pectin Lyase C. The MMER data suggested that the enzymatic sequences interacted with the functional moieties of the polysaccharide molecules and relaxed the close interatomic contacts leading to degradation of the tablet matrix and hence release on the drug in the colonic environment.Enzyme responsive drug delivery: Bawa and coworkers described a stimuli‐synchronized matrix for localized colonic delivery of an anti‐inflammatory drug. The matrix systems were composed of tripolyphosphate crosslinked chitosan dispersed within a BaSOElectroresponsive drug delivery: Indermun and coworkers developed a bipolymeric interfacially plasticized electroresponsive hydrogel composed of a polyacrylic acid‐poly (PAA‐PVA) semiinterpenetrating polymer network impregnated with poly(ethyleneimine) and 1‐vinylimidazole as electroactive moieties. The molecular mechanics simulations were carried out under solvent conditions and electrostatic charges were applied three‐dimensionally to the matrix system. The researchers theorized that polymers undergo a very complex electro‐induced organization and then re‐organize when electrical stimulation was removed. The jump‐diffusional behavior shown by the electroactive molecules played a major role in drug release on the application of electric field . Hyaluronan (HYA) polymer chains in particular showed geometrical variations and interactions with the hydroxyl ions  dissolution and/or degradation profiles and the arrangement of these selected entities into a layered or multicomponent platform.Stimuli and environmentally responsive drug delivery systems form an important aspect of current drug delivery strategies given the “delivered only when needed” characteristic of these specialized platforms. These systems can be easily, but nonconclusively, classified as thermo‐, pH‐, electro‐, light‐, ion‐, oxidation‐, and enzyme responsive.Molecular modeling studies of such complex systems are very limited in the literature. The major limitation of achieving the “responsiveness” in silico stems from the unavailability of modeling platforms for perfect environmental simulation and control and need innovative solutions to elucidate the responsive behavior.6This section details a series of mucoadhesion and interaction molecular modeling studies carried out by the authors over the years (2010 onward; Table 7The above discussion and cited literature proved that not‐so‐complex and time‐efficient molecular mechanics simulations can provide an in depth account of the bonding and nonbonding interactions occurring within a biomedical device or system fabricated using biopolymers. The static‐lattice atomistic simulations and MMER also confirmed that there is a direct relationship between the in silico findings and the in vitro and/or in vivo results and hence atomistic simulations can be employed for the construction of an “in vitro—in vivo—ex vivo—in cyto—in silico” performance‐correlation profile within biomedical material assemblies.The authors declare that they have no conflicts of interest with the contents of this article.


Participants with higher baseline EDVR self-reported lower impulsivity, and discounted rewards as a function of delay more strongly after receiving L-DOPA, whereas the opposite was detected for those with lower baseline EDVR. Our findings support a relationship of striatal dopaminergic activity to trait impulsivity, and the view that there is a non-linear, possibly inverted U-shaped relationship of striatal dopaminergic function with delay discounting. Individuals with optimal dopamine signaling would become more impulsive when receiving dopamine-enhancing drugs, whereas those with suboptimal dopaminergic signaling would benefit and exhibit less impulsive choice. Consideration of differences in endogenous dopamine signaling and possibly also other neurotransmitter activity may be crucial to advance understanding of the neurobiochemical mechanisms of impulsive decision-making and related mental disorders.We previously reported that L-DOPA effects on reward-based decision-making in a randomized, placebo-controlled, double-blind, crossover study were consistent with an inverted U-shaped function whereby both low and high extremes of dopamine signaling are associated with high-impulsive choice. To test this hypothesis, we performed [ Additional dimensions of decision-making encompass the propensity to overweight potential losses relative to equivalent gains (loss aversion) and to take risks to avoid certain losses (risk-seeking for losses). In part because dopamine-enhancing drugs are efficacious in the treatment of mental disorders  but also are abused5, an important role in decision-making has been attributed to dopamine. Since everyday life is full of choices involving trade-offs between reward magnitudes and probabilities or delays , one approach to delineate the role of dopamine is through pharmacological studies in healthy humans. Yet findings have been inconsistent6, with drugs that increase dopamine signaling as well as those that reduce it, both of which have been shown to boost and diminish impulsive choice7.Various mental health problems, including addictive behaviors7. Moreover, changes in performance on delay discounting and mixed gambles tasks depended on trait impulsivity7. Participants with low impulsivity discounted rewards as a function of delay more strongly (measured by a delay discounting task), became more risk-seeking for gains (on a probability discounting for gains task) and more loss averse (on a mixed gambles task) after L-DOPA intake, whereas the opposite was exhibited by more-impulsive individuals7. In light of positron emission tomography (PET) studies that showed associations of impulsivity with pre- and postsynaptic neurochemical markers for dopamine signaling9, our results suggested an inverted U-shaped function whereby both low and high extremes of dopaminergic activity are linked to impulsive choice. Individuals with optimal dopamine signaling would get overdosed by dopamine-enhancing drugs, such as L-DOPA, and become more impulsive, whereas those with suboptimal dopaminergic signaling would make less impulsive choices.In a randomized, placebo-controlled, double-blind, crossover study, we recently found that L-DOPA had no main effect on impulsive decision-making, but had an effect on a probability discounting for gains task that was moderated by trait impulsivity as assessed with the Barratt Impulsiveness Scale (BIS-15)11. Findings obtained with a delay discounting task12 and the Balloon Analog Risk Task14, which involves sequential choices to pump a balloon to increase gains while risking explosion or to stop pumping to retain earnings, support this idea. Participants with higher trait impulsivity  showed greater effects of tolcapone, an inhibitor of the dopamine-degrading enzyme catechol-O-methyltransferase (COMT), to reduce discounting of rewards as a function of delay, as compared with less impulsive individuals12. An inverted U-shaped influence of dopamine, as indexed by [18F]fallypride PET13 or a composite score of functional polymorphisms across five genes14, has also been suggested for risky decision-making.Accumulating evidence supports the hypothesis that differences in dopamine signaling in striatal and prefrontal brain regions may underlie the individual variability in dopaminergic drug effects on cognitive control18F]DOPA PET, and determined the effective distribution volume ratio (EDVR), which is the ratio of [18F]DOPA influx rate to [18F]dopamine washout rate, and reflects the level of dopamine available for vesicular storage at steady state15. In a subset of 60 participants from our prior study7, we investigated whether the effects of L-DOPA on decision-making were related to intrinsic variations in striatal dopaminergic activity. We hypothesized that after L-DOPA administration, participants with lower striatal dopaminergic activity, as indexed by EDVR, would exhibit weaker delay discounting, reduced risk-seeking for gains and reduced loss aversion, whereas those with higher dopaminergic activity would show the opposite effects. As previous studies found no L-DOPA effects on risk-seeking for losses16, we predicted that baseline EDVR would not affect performance on a probability discounting for losses task. We further hypothesized that self-reported impulsivity (assessed with the BIS-15) would be negatively correlated with striatal dopaminergic activity.Here we extended prior work to determine if baseline dopaminergic activity affected the response to L-DOPA in several aspects of impulsive choice. As an index of presynaptic dopaminergic terminal function, we used DOPA scan (mean days ± SD after the second intervention visit = 78.2 ± 51.90). Behavioral data evaluating L-DOPA effects on performance of decision-making tasks have been published recently7.We performed DOPA scan  at rest. Carbidopa  was administered 60 min prior to intravenous [18F]DOPA injection to increase striatal activity and the signal-to-noise ratio21. Striatal dopamine availability at steady state was calculated by estimating EDVR on a voxel-wise basis by graphical analysis, and averaging the value within the whole striatum. In exploratory analyses, striatal subregions  were evaluated.Imaging data were acquired and processed as described previouslyWe used SPSS Statistics 25  and assumed two-tailed significance at p < 0.05 for all analyses. Histograms and normal quantile-quantile plots were used to judge normality. To meet the assumptions of parametric testing, k and λ values were log-transformed. All correlations are reported as Pearson’s r.L-DOPA − log k/λPlacebo). We controlled for drug order because some participants received placebo and others L-DOPA first (crossover design). In keeping with our previous analyses7 and studies that observed bodyweight-dependent effects of L-DOPA22, we also controlled for weight and then examined correlations of interest restricted to low-weight participants (≤80.5 kg at L-DOPA visit). Exploratory analyses were carried out to investigate results in striatal subregions: caudate nucleus, putamen and ventral striatum.To address whether EDVR interacted with L-DOPA-induced changes in impulsive choice, we determined partial correlations between whole-striatal EDVR and differences of performance on decision-making tasks between drug conditions (Δlog k/λ = log k/λPlacebo). To check if correlations were confounded, we reassessed all analyses while controlling for potential nuisance variables  that were significantly associated with EDVR in the whole striatum. To interpret non-significant results, we conducted a post-hoc power analysis  using G*Power Version 3.1.9.4 (www.gpower.hhu.de)26.We evaluated correlations between EDVR and trait impulsivity  as well as decision-making performance after participants had taken placebo  reported low to moderate impulsivity (mean BIS-15 ± SD at baseline = 29.9 ± 5.23). The mean (±SD) EDVR for the whole striatum and striatal subregions caudate nucleus, putamen and ventral striatum were 1.45 (±0.18), 1.13 (±0.18), 1.74 (±0.21) and 1.26 (±0.18), respectively.L-DOPA − log k/λPlacebo) in delay-discounting behavior (Δlog kDD) as hypothesized  and loss aversion (Δlog λMG) were not significantly related to EDVR  nor age  significantly influenced EDVR, we found a significant association between season  and EDVR in the whole striatum . Absolute EDVR values (mean ± SD) of participants (n = 25) who underwent the [18F]DOPA scan in the fall-winter period (1.51 ± 0.17) were higher than those of participants (n = 35) examined in spring or summer (1.40 ± 0.18). Controlling for season using partial-correlation analyses however did not substantially impact L-DOPA-induced changes in impulsive choice  tended to predict L-DOPA-induced change in loss aversion  and EDVR in the ventral striatum became significant when controlling for seasonal variation .We considered ageBIS-15 was inversely related to EDVR in the whole striatum as predicted  and also in the ventral striatum  after controlling for seasonal variation. Table A post-hoc power analysis revealed that our whole sample (N = 60) had sufficient power (0.763) to detect correlations of medium (r = 0.3), but not of smaller effect sizes . To avoid increasing the already high type II error probability, we decided against the correction for multiple comparisons in the analyses involving correlations with test performance.Our objective was to investigate whether individual variations in striatal EDVR, an index of presynaptic dopaminergic function, would be related to L-DOPA-induced changes in impulsive choice. As hypothesized, participants who reported low impulsivity exhibited higher EDVR, and discounted reward as a function of delay more strongly after L-DOPA administration, whereas lower EDVR was exhibited by more-impulsive individuals (BIS-15), who exhibited less delay discounting after receiving L-DOPA. Participants with higher EDVR also tended to be more risk-seeking for gains and loss averse after L-DOPA intake, while those with lower baseline EDVR behaved in an opposite way, but this effect reached statistical significance only for the relation between loss aversion and the EDVR in the ventral striatum of low-weight participants, possibly due to a stronger L-DOPA effect because dose was not adjusted for body weight. As hypothesized, differential baseline dopamine availability did not moderate L-DOPA-induced changes in risk-seeking for losses.11. This theory implies that contrasting effects on cognition may occur depending on how dopaminergic drugs shift dopaminergic activity on this curve. Such an influence of dopaminergic function has also been assumed in a study in which tolcapone, an inhibitor of the dopamine-degrading enzyme catechol-O-methyltransferase (COMT), reduced delay discounting in participants with high impulsivity, whereas low-impulsive participants  exhibited smaller declines or enhancements in delay discounting12. Of note, tolcapone may preferentially increase frontal dopamine as the dopamine transporter (DAT), which inactivates dopamine by reuptake, is considerably less abundant in frontal than other brain regions12. The data from that study indicated a circuit mechanism for dopamine effects since delay discounting varied with tolcapone-induced changes in the left ventral putamen and the frontostriatal connectivity12.Our study adds to the mounting evidence that the relationship between dopamine signaling and cognitive function is not linear, but follows an inverted U-shaped curve18F]fluoro-meta-tyrosine as radiotracer to measure dopamine synthesis capacity27. The independence of the negative association between putaminal PET signal and delay discounting of COMT genotype27 endorses the hypothesis that individual variability of dopaminergic activity in both the frontal cortex and putamen modulates delay discounting. An inverted U-shaped dopamine function has also been concluded from associations between delay-discounting behavior and left caudate synthesis capacity using [18F]DOPA in patients with Parkinson’s disease and ventral striatal D2/D3 dopamine receptor availability using [11C]raclopride in pathological gamblers28. The latter adds to the literature that links delay discounting to dopaminergic activity in the ventral striatum29, whereby distinct and partly opponent mechanisms in impulsivity have been attributed to its subregions the core and shell of the nucleus accumbens29. The low spatial resolution of PET, which did not allow us to disentangle these subregions, may have caused net cancellation of effects as speculated previously27.Our finding that low EDVR in the putamen but not in the caudate nucleus or ventral striatum was related to delay discounting (under placebo) is consistent with that of a PET study in 16 healthy adults using fallypride PET13. In line with these findings, our data show a tendency of caudate presynaptic dopaminergic activity predicting L-DOPA-induced changes in delay discounting and trends of positive association between change in loss aversion and dopamine in the caudate nucleus and the ventral striatum. L-DOPA-induced changes in risk-seeking for gains were inversely correlated to striatal dopamine as predicted, albeit far from reaching statistical significance. Although our study lacks power to detect correlations of smaller effect sizes, the literature indicates that different brain networks, neurotransmitters and possibly a family of functions  are differently involved in distinct facets of impulsive choice30. Consistent with our previous work7 and other reports31, we found no evidence for dopaminergic neurotransmission affecting risk-seeking for losses. In fact, serotonergic tone may modulate the sensitivity towards valuation of losses31.Further support for the inverted U-shaped concept comes from studies on risky decision-making applying the Balloon Analogue Risk Task and assessing striatal dopaminergic signaling using a composite score of functional polymorphisms across five genes encoding dopamine receptors , DAT and COMT9, with contrasting data reported in small-sample studies limited to BIS subscales33. Higher BIS-11 impulsivity and lower striatal D2/D3 availability were found in recently abstinent methamphetamine-dependent individuals compared to healthy controls with BIS-11 related to D2/D3 receptor availability across both groups9. Higher BIS-11 scores also correlated with higher striatal DAT availability (consistent with lower dopaminergic tone) in 38 healthy men8. Our data based on a different PET tracer in a large sample of healthy men and women support these results, which may be reconciled with an inverted U-shaped function, assuming that the relation between dopamine (increasing from left to right on x-axis) and BIS (decreasing from bottom to top on y-axis) reflects the ascending limb while the descending limb does not appear as acutely overdosed individuals were not tested.Research findings suggest that greater trait impulsivity as measured by BIS is characterized by lower dopamine signalingIn conclusion, this study corroborates and extends previous findings demonstrating the importance of dopamine signaling in impulsivity by providing further insights into the biological underpinnings of impulsive decision-making. Our data indicate that lower dopaminergic activity in the striatum is a correlate of stronger trait impulsivity and delay discounting. They also suggest that the latter can be modulated by dopaminergic drugs depending on individual variations in the striatal dopamine system, possibly following an inverted U-shaped curve. Whereas substantial evidence identifies dopamine as a crucial determinant of delay-discounting behavior, our results highlight that distinct dimensions of impulsive decision-making seem to be differently regulated. Yet our findings must be interpreted with caution since we did not correct for multiple comparisons in the analyses involving correlations with test performance.35.Appreciation of variations in endogenous dopamine availability and the complexity of different neurotransmitter and brain systems implicated in impulsivity are therefore needed in future pharmacological studies. The identification of mutual as well as unique neural underpinnings of different facets of impulsive choice will advance our understanding of impulsivity and may also offer new insights into related mental health problems. In fact, impulsive choice has already been considered as a promising target for the development of more effective interventions across mental disorders


The surface morphology of PbTe nanofibers was strongly dependent on the diameter of sacrificial nanofibers where it altered from smooth to rough surface as the Pb2+ concentration increased. Some of thermoelectric properties  were systematically measured as a function of temperature. Energy barrier height (Eb) was found to be one of the key factors affecting the thermoelectric properties–that is, higher energy barrier heights increased the Seebeck coefficient, but lowered the electrical conductivity.Lead telluride (PbTe) nanofibers were fabricated by galvanic displacement of electrospun cobalt nanofibers where their composition and morphology were altered by adjusting the electrolyte composition and diameter of sacrificial cobalt nanofibers. By employing Co instead of Ni as the sacrificial material, residue-free PbTe nanofibers were synthesized. The Pb content of the PbTe nanofibers was slightly affected by the Pb ZT = S2σT/κ), which consists of thermopower , electrical conductivity (σ), and thermal conductivity (κ), and absolute temperature (T). In order to maximize the ZT, there parameters must be independently optimized. However, the interdependence of S, σ, and κ make difficult to further enhance ZT , by means of quantum confinement and/or the energy filtering effect or reducing lattice thermal conductivity (κL) by enhanced phonon scattering    is a V-VI semiconductor with a narrow band-gap energy of 0.31 eV at room temperature with a rock-salt crystal structure. By adjusting the composition, PbTe can be either an n- or p-type semiconductor. For example, Te-rich PbTe results in p-type semiconductor whereas Pb-rich PbTe results in n-type semiconductor  and cobalt acetate  at a molar ratio of 1 were dissolved in 6.3 g of water followed by mixing with 3.34 g of anhydrous ethanol solution  containing 5.2 wt. % of polyvinylpyrrolidone (PVP). MW of PVP was 1,300,000 g/mol. The concentration of the precursor solution was varied to electrospin the Co sacrificial nanofibers with two different diameters. The concentration of cobalt acetate was chosen to be 1.0 M (solution 1) and 1.6 M (solution 2) based on the spinnability of the solution and the solubility of the salt. A 0.25 mm inner diameter metallic needle was used as the spinneret. The applied voltage and the distance between spinneret and collector  were fixed at 10 kV and 10 cm, respectively. The flow rate was fixed at 0.5 mL/ h using a peristaltic pump. The electrospinning time was fixed at approximately 15 min to keep the thickness of collected nanofiber mats consistent. The temperature and relative humidity were 40 ± 2°C and 8 ± 1%, respectively. The collected nanofibers were first aged at 60°C in air overnight and then calcined at 500°C in pure H2 for 5 h to obtain Co nanofibers.The procedure of electrospinning of cobalt nanofibers is based on previous reported nickel nanofibers  and 0.1 M nitric acid  The pH of solution was controlled to be 2 by adding nitric acid . The effects of Pb+2 concentration on the morphology and dimension of the nanofiber were conducted by altering the Pb2+concentrations from 10 to 100 mM. After galvanic displacement, the mats were rinsed with de-ionized water five times follow by air dried.The galvanic displacement of cobalt to PbTe nanofiber mat was conducted at room temperature for 30 min by dipping a freestanding Co nanofiber mat of the desired amount into 10 ml solution. The solution consisted of X mM lead nitrate (Pb(NO3)2, Fisher Chemical), 0.1 mM tellurium oxide , respectively.Transmission electron microscopy (TEM), selected area electron diffraction (SAED), field emission-scanning electron microscopy , energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction  were used to characterize morphologies, compositions, crystal structures and crystallinity of the nanofiber mats.Single fiber-based devices were fabricated by a standard photolithography process with a gap size of 3 μm between two Au pads. Nanofiber mats based devices were formed by sputtering Pt to form electrodes using shadow mask technique with the fixed electrode gap distance of 1 mm.Temperature-dependent electrical properties including current-voltage (I-V) and field-effect transient (FET) measurements were characterized based on the single fiber-based devices at a temperature ranging from 293 to 353 K, while thermopower (S) was measured based on mats by a home-built instrument. The temperature range was varied from 300 to 360 K.2/citric acid/PVP nanofibers were electrospun from both solutions, as shown in Figures 2 environment led to a complete decomposition of the polymer and acid as well as the formation of continuous Co nanofibers  is more cathodic than that of the Pb2+/Pb (−0.13 V vs. SHE) and 2+ and 2+ (Equation 1) as well as the formation of PbTe. Here, Co nanofibers served as both the electron source and the template for the PbTe deposition. The deposition would initiate with overpotential deposition of Te nuclei on the surface of the Co nanofibers (Equation 2), due to a more negative standard reduction potential of Co than Te. Pb spontaneously deposited on Te by underpotential deposition (UPD) mechanism, which resulted in the formation of PbTe. PbTe compound is formed instead of Pb and Te due to the negative ΔG of PbTe formation (Equation 3)  for the metal chalcogenide displacement. Since the redox potential of Coi.e., 52 and 124 nm) and the concentrations of Pb2+  in the electrolytes and, while maintaining the concentrations of HNO3 and 3 in the PbTe's electrolytes was ten times lower  to reduce the dissolution rate of Co, which is much faster than that of Ni , to 50 mM (middle column), and to 100 mM (right column). All three conditions produced nanofibers, some of them with clear hollow structures  = 10 mM and 50 mM] was first observed, followed by a slight increase in the Pb content when the concentration of Pb2+ was increased to 100 mM. Variations in the ion concentration had minor effects on the fibers' composition because the Pb content maintained at around 42 at.% and only a 7 at. % (from 37 at.% to 44 at.%) change was observed corresponding to a one order of magnitude change in the electrolyte concentration. The insignificant effect of a high Pb2+ concentration ([Pb2+] ≥ 50 mM) on the composition of PbTe has been suggested in our previous work  . In Chang's thin film system, Te-rich PbTe films were obtained at [Pb2+]/[2+]/[2+]/. The smaller PbTe nanofibers were rougher than the larger PbTe nanofibers, which might be due to the rougher surface of small Co nanofibers. The Pb2+ concentration had negligible effects on the fibers' composition in the studied range. No residue of Co was observed in the fibers after the galvanic displacement reactions, which indicated a complete reaction. The outer diameter of PbTe nanofibers increased with the Pb2+ concentration. XRD analysis showed that all synthesized PbTe samples were polycrystalline in nature.PbTe nanofiber mats were fabricating using electrospun cobalt nanofibers as the sacrificial materials. Control over the dimension and morphology of the nanofibers were achieved by applying sacrificial material with various diameters and tuning the concentration of PbThe temperature-dependent I-V characterization was conducted based on single PbTe nanofibers. The electrical conductivity decreased as the Pb content in the nanofibers decreased. It could be suggested that the excess Te created barriers in the nanofibers, increasing the barrier height while decreasing the electrical conductivity.MZ, JK, and MN conducted the experiments. SK conducted TEM analysis. S-DP, YC, JL, and NM provided funding and inputs to the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


One of the main problems involved in heart transplantation (HT) is antibody-mediated rejection (AMR). Many aspects of AMR are still unresolved, including its etiology, diagnosis and treatment. In this project, we hypothesize that variants in genes involved in B-cell biology in HT patients can yield diagnostic and prognostic information about AMR.Genetic variants in 61 genes related to B-cell biology were analyzed by next generation sequencing in 46 HT patients, 23 with and 23 without AMR.ITGA4 gene  that conformed the haplotype AGT-ITGA4. This haplotype is associated with the development of AMR. Moreover, AMR patients with the haplotype AGT-ITGA4 present lower levels of integrin α-4 in serum samples compared to the reference GAC haplotype in control patients.We identified 3 single nucleotide polymorphisms in ITGA4 gene could potentially increase the risk of AMR.We can conclude that polymorphisms in genes related to the biology of B-cells could have an important role in the development of AMR. In fact, the AGT haplotype in  The spectrum of clinical rejection in heart transplantation (HT) involves both arms of the adaptive immune response, the T cell-mediated response leading to cellular rejection (CR), and the humoral response leading to antibody-mediated rejection (AMR) . The humThe occurrence and severity of AMR are variable, and genetic polymorphisms that affect the magnitude and nature of the B-cell response are likely to contribute to such phenotypic variation. In fact, several studies investigated the relationship between single nucleotide polymorphisms (SNPs) in genes known to impact B-cell activation/function and antibody effector function ,4. In thWe hypothesize that variants in exon-coding sequences and surrounding area of genes involved in B-cell biology in HT patients can yield diagnostic and prognostic information about AMR. Thus, identifying variants associated with AMR might allow risk stratification of patients and a genetic-based immunosuppression regimen.Complejo Hospitalario Universitario de A Coruña (CHUAC). The study was carried out on 46 HT recipients, 23 with and 23 without AMR diagnosis, who underwent the transplantation between June 2000 and November 2016 , which correlates with the development of AMR. These 3 SNPs conform a haplotype: AGT-ITGA4, which could be associated with development of AMR in HT patients. Our data showed that the AGT haplotype in ITGA4 gene in AMR patients present lower levels of integrin α-4 in serum samples compared to the reference GAC haplotype in control patients. In the past decade, efforts to understand how an individual´s genetic can impact on disease susceptibility, severity and responses to treatment have progressed rapidly and the AGT haplotype described in this study could open a new approach to AMR.The present data represents the first study on the effect of variants on genes involved in the B-cell biology related to AMR in HT patients to date. We have identified three SNPs in ITGA4 gene, plays a particularly prominent role in the immune system through its adhesive and signalling functions [Cell adhesion is critical in immune system function, and α4 integrin , encoded by unctions . These functions . Moreoveunctions . The prounctions –29.vβ6, which belong to another family of integrins but with similar functions to α4 integrin, are increased in acute CR of heart allograft and cardiac allograft vasculopathy in humans [v integrin antagonist was able to significantly ameliorate the infiltration of CD8+ T cells and macrophages into the graft and inhibit proliferation of mononuclear cells and fibroblasts in the interstitium of kidney allografts [In the field of transplantation, most of the studies focus on integrins were done in CR due to their role in T-cells. It has been described that αn humans ,31. In tlografts . Treatmelografts . Moreovelografts ,35.ITGA4 genotype and α4 integrin expression focus on AMR patients. In our cohort, the haplotype AGT present a higher frequency in patients with AMR and it is associated with lower serum levels of α4 integrin. To explain a possible role of α4 integrin in AMR, we have to take into account that α4 integrin are expressed at higher levels by B-cell precursors than mature B-cells [ITGA4 gene could have an impact in GBP1 induction, which in turn may result in a higher endothelial cell proliferation and migration during AMR. Furthermore, a down-regulation of the ITGA4 gene has also been described in other diseases, such as Crohn´s disease [Our study is the first analysis of  B-cells . Thus, w B-cells . Moreove B-cells . Thus, a disease  or the f disease . InteresThe current study presents some limitations including a retrospective design, a relatively small sample size, and an evolving criteria of AMR definition. However, we believe that this study opens a new pathway of understanding that variants in genes related to the B cell biology may influence the development of AMR, a field not yet explored.ITGA4 gene could increase the risk of AMR. However, the detailed molecular mechanisms on how this haplotype exerts effects in the immune response leading to AMR are unclear and more research must be done to assess its role.The main results of this study are: 1.) AGT haplotype is associated with the development of AMR and 2.) integrin α-4 serum levels in patients carried AGT haplotype are lower that patients carried the reference GAC haplotype. Thus, polymorphisms in the genes related to the biology of B-cells could have an important role in the development of AMR in cardiac transplants. Specifically, the AGT haplotype in S1 FigIn the bone marrow, development progresses through the pro-B cell and pre-B cell, immature-B cell stages and the most important genes involved are showed. During this differentiation, rearrangements at the immunoglobulin locus result in the generation and surface expression of the pre-B cell receptor and finally a mature B cells that are capable of binding antigen. The 61 genes analysed in this study are showed in bold.(TIF)Click here for additional data file.S1 Table(DOC)Click here for additional data file.S2 Table(DOC)Click here for additional data file.S3 Table(DOC)Click here for additional data file.S4 Table(DOC)Click here for additional data file.