Proteomic dynamics revealed sex-biased responses to combined heat-drought stress in Marchantia.

Recent studies have documented plant responses to climate change extensively, particularly to single-stress exposures. However, critical factors for stress survival, such as sexual differentiation, are not often considered. The dioicous Marchantia polymorpha stands as an evolutionary milestone, potentially preserving ancestral traits from the early colonizers. In this study, we employed proteomic analyses complemented with physiological monitoring to investigate combined heat and drought responses in Tak-1 (male) and Tak-2 (female) accessions of this liverwort. Additionally, targeted transcriptomics was conducted using different natural populations from contrasting environments. Our findings revealed sex-biased dynamics among natural accessions, particularly evident under control conditions and during early stress responses. Although Tak-2 exhibited greater diversity than Tak-1 under control conditions, male accession demonstrated distinct and more rapid stress sensing and signaling. These differences in stress response appeared to be strongly related to sex-specific plasticity influenced by geoclimatic origin. Furthermore, we established distinct protein gene ages and genomic distribution trends, underscoring the importance of protein diversification over time. This study provides an evolutionary perspective on sexual divergence and stress emergence employing a systems biology approach, which allowed for the establishment of global and sex-specific interaction networks in the stress response.

Quadricipital Tendon Simultaneous Bilateral Tear in a Patient with Type-II Diabetes Mellitus after Low-energy Trauma: Case Report.

Simultaneous bilateral rupture of the quadricipital tendon is an extremely rare lesion. We report a case of this injury after low-energy trauma in a patient with type-II diabetes mellitus. Both knees were surgically approached in the same surgical procedure. Early rehabilitation is essential for the adequate functional recovery of the knee. The aim of the present report was to describe an atypical case of this type of injury after minimal trauma, as well as to detail the surgical technique used to treat it.

Molecular Graphene Nanoribbon Junctions.

One of the challenges for the realization of molecular electronics is the design of nanoscale molecular wires displaying long-range charge transport. Graphene nanoribbons are an attractive platform for the development of molecular wires with long-range conductance owing to their unique electrical properties. Despite their potential, the charge transport properties of single nanoribbons remain underexplored. Herein, we report a synthetic approach to prepare N-doped pyrene-pyrazinoquinoxaline molecular graphene nanoribbons terminated with diamino anchoring groups at each end. These terminal groups allow for the formation of stable molecular graphene nanoribbon junctions between two metal electrodes that were investigated by scanning tunneling microscope-based break-junction measurements. The experimental and computational results provide evidence of long-range tunneling charge transport in these systems characterized by a shallow conductance length dependence and electron tunneling through >6 nm molecular backbone.

PlantFUNCO: Integrative Functional Genomics Database Reveals Clues into Duplicates Divergence Evolution.

Evolutionary epigenomics and, more generally, evolutionary functional genomics, are emerging fields that study how non-DNA-encoded alterations in gene expression regulation are an important form of plasticity and adaptation. Previous evidence analyzing plants' comparative functional genomics has mostly focused on comparing same assay-matched experiments, missing the power of heterogeneous datasets for conservation inference. To fill this gap, we developed PlantFUN(ctional)CO(nservation) database, which is constituted by several tools and two main resources: interspecies chromatin states and functional genomics conservation scores, presented and analyzed in this work for three well-established plant models (Arabidopsis thaliana, Oryza sativa, and Zea mays). Overall, PlantFUNCO elucidated evolutionary information in terms of cross-species functional agreement. Therefore, providing a new complementary comparative-genomics source for assessing evolutionary studies. To illustrate the potential applications of this database, we replicated two previously published models predicting genetic redundancy in A. thaliana and found that chromatin states are a determinant of paralogs degree of functional divergence. These predictions were validated based on the phenotypes of mitochondrial alternative oxidase knockout mutants under two different stressors. Taking all the above into account, PlantFUNCO aim to leverage data diversity and extrapolate molecular mechanisms findings from different model organisms to determine the extent of functional conservation, thus, deepening our understanding of how plants epigenome and functional noncoding genome have evolved. PlantFUNCO is available at https://rocesv.github.io/PlantFUNCO.

Quadricipital Tendon Simultaneous Bilateral Tear in a Patient with Type-II Diabetes Mellitus after Low-energy Trauma: Case Report / Ruptura bilateral simultânea do tendão quadricipital em paciente portador de diabetes mellitus do tipo II após trauma de baixa energia: Relato de caso

Abstract Simultaneous bilateral rupture of the quadricipital tendon is an extremely rare lesion. We report a case of this injury after low-energy trauma in a patient with type-II diabetes mellitus. Both knees were surgically approached in the same surgical procedure. Early rehabilitation is essential for the adequate functional recovery of the knee. The aim of the present report was to describe an atypical case of this type of injury after minimal trauma, as well as to detail the surgical technique used to treat it.

Resumo A ruptura bilateral simultânea do tendão do quadríceps é uma lesão extremamente rara. Relatamos um caso desta lesão após trauma de baixa energia em paciente portador de diabetes mellitus do tipo II. O diagnóstico é essencialmente clínico, e requer tratamento precoce. Os dois joelhos foram abordados cirurgicamente no mesmo ato operatório. A reabilitação precoce é fundamental para a recuperação funcional adequada do joelho. O objetivo deste relato foi descrever um caso atípico deste tipo de lesão após trauma mínimo, bem como detalhar a técnica cirúrgica utilizada para o tratamento.

Evolutionary adaptation from hydrolytic to oxygenolytic catalysis at the α/ß-hydrolase fold.

Protein fold adaptation to novel enzymatic reactions is a fundamental evolutionary process. Cofactor-independent oxygenases degrading N-heteroaromatic substrates belong to the α/ß-hydrolase (ABH) fold superfamily that typically does not catalyze oxygenation reactions. Here, we have integrated crystallographic analyses under normoxic and hyperoxic conditions with molecular dynamics and quantum mechanical calculations to investigate its prototypic 1-H-3-hydroxy-4-oxoquinaldine 2,4-dioxygenase (HOD) member. O2 localization to the "oxyanion hole", where catalysis occurs, is an unfavorable event and the direct competition between dioxygen and water for this site is modulated by the "nucleophilic elbow" residue. A hydrophobic pocket that overlaps with the organic substrate binding site can act as a proximal dioxygen reservoir. Freeze-trap pressurization allowed the structure of the ternary complex with a substrate analogue and O2 bound at the oxyanion hole to be determined. Theoretical calculations reveal that O2 orientation is coupled to the charge of the bound organic ligand. When 1-H-3-hydroxy-4-oxoquinaldine is uncharged, O2 binds with its molecular axis along the ligand's C2-C4 direction in full agreement with the crystal structure. Substrate activation triggered by deprotonation of its 3-OH group by the His-Asp dyad, rotates O2 by approximately 60°. This geometry maximizes the charge transfer between the substrate and O2, thus weakening the double bond of the latter. Electron density transfer to the O2(π*) orbital promotes the formation of the peroxide intermediate via intersystem crossing that is rate-determining. Our work provides a detailed picture of how evolution has repurposed the ABH-fold architecture and its simple catalytic machinery to accomplish metal-independent oxygenation.

The 2-pyridone/2-hydroxypyridine tautomerism in gas phase: An excited state roaming reaction.

Multiconfigurational methods (CASSCF and CASPT2) were employed to gain a new understanding of the mechanism of the gas-phase phototautomerization of 2-pyridone/2-hydroxypyridine. Potential energy curves and crossing points of the low-lying excited states were analyzed. The results show that the tautomerization only occurs from 2-pyridone to 2-hydroxypyridine after electronic excitation to the S1 (ππ*) state. From this state, the system would be able to reach a conical intersection between S1 and the dissociative S2 (πσ*) due to vibrational effects. Then, it can evolve to the hydroxy form in its ground state by reaching an intersection seam between the S0 and the πσ* states. For this to happen, a roaming process responsible for the hydrogen atom migration would be required; otherwise, the system would revert to the 2-pyridone tautomer. The unfeasibility of the reverse process after optical excitation from the lactim to the lactam form is explained by the great amount of energy needed to reach the conical intersection between the ππ* and πσ* states. These findings would provide new insights into the understanding of the photophysics and photochemistry of a primordial heterocycle, considered a prebiotic model known to be found in interstellar clouds.

Direct C-H Arylation of Dithiophene-Tetrathiafulvalene: Tuneable Electronic Properties and 2D Self-Assembled Molecular Networks at the Solid/Liquid Interface.

Invited for the cover of this issue is the group of Manuel Souto and co-workers at the University of Aveiro and CICECO-Aveiro Institute of Materials. The image depicts the direct C-H arylation of dithiophene-tetrathiafulvalene (DT-TTF) and the self-assembly of DT-TTF-tetrabenzoic acid studied by using scanning tunnelling microscopy. Read the full text of the article at 10.1002/chem.202300572.

Spin-Forbidden Addition of Molecular Oxygen to Stable Enol Intermediates-Decarboxylation of 2-Methyl-1-tetralone-2-carboxylic Acid.

The deprotonation of an organic substrate is a common preactivation step for the enzymatic cofactorless addition of O2 to this substrate, as it promotes charge-transfer between the two partners, inducing intersystem crossing between the triplet and singlet states involved in the process. Nevertheless, the spin-forbidden addition of O2 to uncharged ligands has also been observed in the laboratory, and the detailed mechanism of how the system circumvents the spin-forbiddenness of the reaction is still unknown. One of these examples is the cofactorless peroxidation of 2-methyl-3,4-dihydro-1-naphthol, which will be studied computationally using single and multi-reference electronic structure calculations. Our results show that the preferred mechanism is that in which O2 picks a proton from the substrate in the triplet state, and subsequently hops to the singlet state in which the product is stable. For this reaction, the formation of the radical pair is associated with a higher barrier than that associated with the intersystem crossing, even though the absence of the negative charge leads to relatively small values of the spin-orbit coupling.

Direct C-H Arylation of Dithiophene-Tetrathiafulvalene: Tuneable Electronic Properties and 2D Self-Assembled Molecular Networks at the Solid/Liquid Interface.

Tetrathiafulvalene is among the best known building blocks in molecular electronics due to its outstanding electron-donating and redox properties. Among its derivatives, dithiophene-tetrathiafulvalene (DT-TTF) has attracted considerable interest in organic electronics, owing to its high field-effect mobility. Herein, we report the direct C-H arylation of DT-TTF to synthesise mono- and tetraarylated derivatives functionalised with electron-withdrawing and electron-donating groups in order to evaluate their influence on the electronic properties by cyclic voltammetry, UV-vis spectroscopy and theoretical calculations. Self-assembly of the DT-TTF-tetrabenzoic acid derivative was studied by using scanning tunnelling microscopy (STM) which revealed the formation of ordered, densely packed 2D hydrogen-bonded networks at the graphite/liquid interface. The tetrabenzoic acid derivative can attain a planar geometry on the graphite surface due to van der Waals interactions with the surface and H-bonding with neighbouring molecules. This study demonstrates a simple method for the synthesis of arylated DT-TTF derivatives towards the design and construction of novel π-extended electroactive frameworks.

Low Incidence of Acute Antibody-Mediated Rejection after HLA Desensitization in Living Donor Kidney Transplant Recipients.

Desensitization allows the performance of human leukocyte antigen (HLA)-incompatible transplants. However, the incidence of acute rejection (AR) is high. This study aims to analyze the incidence of AR after transplantation with HLA-incompatible living donors in patients who underwent desensitization. Patients were immunosuppressed with tacrolimus, mycophenolic acid derivatives, and steroids after being desensitized with rituximab, plasma exchange, and/or immunoadsorption with specific cytomegalovirus immunoglobulins. A negative complement-dependent cytotoxicity or flow cytometry crossmatch and a donor-specific antibody titer < 1000 mean fluorescence intensity (MFI) were used to determine desensitization efficacy. A total of 36 patients underwent desensitization, and 27 (75%) were transplanted. After a follow-up of 58 ± 58 months (Min−Max: 0.13−169.5), five episodes of AR occurred: two antibody-mediated and three T-cell-mediated. No differences were found in baseline calculated panel-reactive antibodies (cPRA), class I or II MFI, number of antibodies, or Relative Intensity Scale (RIS) between AR and non-AR patients. Patients with antibody-mediated AR had higher cPRA (NS), MFI class I (p = 0.07) and class II (p = 0.006), and RIS (p = 0.01). The two patients with antibody-mediated AR and one patient with T-cell-mediated AR lost their grafts. In conclusion, the incidence of acute antibody-mediated rejection after desensitization was 7.4%, which occurred early post-transplantation in patients with high MFI and was associated with early graft loss.

Development of an Electrochemical CCL5 Chemokine Immunoplatform for Rapid Diagnosis of Multiple Sclerosis.

Serum level of CCL5 chemokine is considered an emerging biomarker for multiple sclerosis (MS). Due to the lack of specific assays for this disease, the development of a point-of-care test for rapid detection of MS could lead to avoiding diagnostics delays. In this paper, we report the first electrochemical immunoplatform for quantification of the CCL5 biomarker at the clinically required levels, able to discriminate between patients diagnosed with MS and healthy individuals. The immunosensing device involves protein capture from biological samples by complexation with biotinylated specific antibodies immobilized onto neutravidin-functionalized microparticles and sandwich assay with anti-CCL5 antibody and IgG labelled with horseradish peroxidase (HRP) for the enzyme-catalyzed amperometric detection of H2O2 using hydroquinone (HQ) as the redox mediator. The method shows excellent analytical performance for clinical application with a wide linear range of concentrations (0.1-300 ng·mL-1 CCL5, R2 = 0.998) and a low detection limit (40 pg·mL-1 CCL5). The biosensing platform was applied to the determination of the CCL5 endogenous content in 100-fold diluted sera both from healthy individuals and patients diagnosed with MS, with no further sample treatment in just two hours. The results were successfully compared with those obtained by the ELISA methodology.

Gamification in the microbiology classroom for biology students during the COVID-19 pandemic / Gamificación en el aula de microbiología para estudiantes de Biologia durante la pandemia COVID-19 / Gamificação na sala de aula de microbiologia para estudantes de biologia durante a pandemia da COVID-19

ABSTRACT Gamification is an underdeveloped didactic method in the microbiology classroom, mainly due to teachers' limited experience with ICT. However, it can positively influence learning, especially in virtual environments such as those established by the COVID-19 pandemic. This work aimed to analyze the effects of gamification applied to microbiology classes in Biology students in blended and online modalities under the current context. A focus group of students, who experienced the didactics of gamification, Problem-Based Learning, and Project-Based Learning, was surveyed to determine the effects of these methods on its learning. Teachers and graduates also approached gamification, and their responses were analyzed. Students considered that gamification contributed to their engagement in the learning process, increasing the interest in classroom activities. The results also indicated that the three didactic approaches complemented each other and can be integrated into the face-to-face curriculum. Evidence denoted that gamification can indeed enhance cognitive, metacognitive, praxeological, and attitudinal skills, thereby bettering the learning experience.

RESUMEN La gamificación es un método didáctico poco desarrollado en el aula de microbiología debido principalmente al bajo dominio de herramientas TIC en los docentes. Sin embargo, puede tener efectos positivos en el aprendizaje, especialmente en entornos virtuales como los establecidos obligatoriamente por la pandemia COVID-19. El objetivo de este trabajo fue analizar los efectos de la gamificación aplicada al aprendizaje de las clases de microbiología en estudiantes de Biología en modalidad de alternancia y virtual bajo el contexto actual. Se encuestó a un grupo focal de estudiantes, quienes experimentaron las didácticas de gamificación, Aprendizaje Basado en Problemas y Aprendizaje Basado en Proyectos, para determinar los efectos sobre su aprendizaje. Docentes y egresados también fueron usuarios de la gamificación, y sus respuestas analizadas. Los estudiantes consideraron que la gamificación contribuyó con su proceso de aprendizaje al ayudar a potenciar su interés por las actividades de clase. Los resultados también indicaron que las didácticas son complementarias e incorporables en el curriculum presencial. La evidencia probó que la gamificación puede mejorar el desarrollo de habilidades cognitivas, metacognitivas, praxeológicas y actitudinales, además de mejorar la experiencia de aprendizaje.

RESUMO A gamificação é um método didático pouco desenvolvido na sala de aula de microbiologia, principalmente devido ao baixo domínio das ferramentas TIC pelos professores. No entanto, pode ter efeitos positivos na aprendizagem, especialmente em ambientes virtuais como os exigidos pela pandemia COVID-19. O objetivo deste trabalho foi analisar os efeitos da gamificação aplicada à aprendizagem das classes da microbiologia em alunos de Biologia na modalidade semipresencial e virtual no contexto atual. Um grupo focal de alunos, que experimentou as didáticas da gamificação, Aprendizagem Baseada em Problemas e Aprendizagem Baseada em Projetos, foi entrevistado para determinar os efeitos em sua aprendizagem. Professores e graduados também foram usuários da gamificação e suas respostas analisadas. Os alunos consideraram que a gamificação contribuiu em seu processo de aprendizagem, ajudando a aumentar seu interesse nas atividades de aula. Os resultados também indicaram que as didáticas são complementares e podem ser incorporadas no curriculum presencial. As evidéncias mostraram que a gamificação pode aprimorar o desenvolvimento de habilidades cognitivas, metacognitivas, praxeológicas e atitudinais, além de aprimorar a experiéncia de aprendizagem.

Incidence and Related Factors of Infidelity among Medical Doctors and Nurses.

Although there is a large body of research addressing infidelity, no study, to our knowledge, has specifically addressed infidelity in doctors and nurses and the correlation with work hours, schedule and other variables. This research aimed to know the incidence of and factors related to infidelity among doctors and nurses. A descriptive study was carried out, studying the association of certain variables. In total, 367 volunteer participants completed an online survey. Of them, 21% either have or have had an unfaithful relationship. The majority (81.7%) were doctors. Men were 4.3 times more unfaithful than women, with these differences being statistically significant (OR = 4.37, p < 0.001). Of the participants involved in an unfaithful relationship within the work area, the majority were men. Likewise, those who reported having had sex in the doctor's room on duty were also men, with these differences being statistically significant (OR = 12.81, p < 0.01). The night emergency schedule was 60% more frequent in unfaithful people, and these differences were statistically significant (OR = 12.43, p < 0.01). There is a significant rate of infidelity in doctors and nurses. Men are more likely to be unfaithful than women are, and people who work nighttime emergencies are more likely to be unfaithful.

The effect of spin polarization on the electron transport of molecular wires with diradical character.

Some of the most promising materials for application in molecular electronics and spintronics are based on diradical chains. Herein, the proposed relation between increasing conductance with length and diradical character is revisited using ab initio methods that account for the static electron correlation effects. Electron transmission was previously obtained from restricted single determinant wavefuntions or tight-binding approximations, which are unable to account for static correlation. Broken Symmetry Unrestricted Kohn-Sham Density Functional Theory (BS-UKS-DFT) in combination with electron transport analysis based on electron deformation orbitals (EDOs) reflects an exponential decay of the electrical conductance with length. Also, other important effects such as quantum interference are correctly accounted for, leading to a decrease of the conductance as the diradical character increases. As a proof-of-concept, the electrical conductance obtained from BS-UKS-DFT and CASSCF(2,2) wavefunctions were compared in diradical graphene strips in the frame of the pseudo-π approach, obtaining very similar results.

Proteometabolomic characterization of apical bud maturation in Pinus pinaster.

Bud maturation is a physiological process that implies a set of morphophysiological changes that lead to the transition of growth patterns from young to mature. This transition defines tree growth and architecture, and in consequence traits such as biomass production and wood quality. In Pinus pinaster Aiton, a conifer of great timber value, bud maturation is closely related to polycyclism (multiple growth periods per year). This process causes a lack of apical dominance, and consequently increased branching that reduces its timber quality and value. However, despite its importance, little is known about bud maturation. In this work, proteomics and metabolomics were employed to study apical and basal sections of young and mature buds in P. pinaster. Proteins and metabolites in samples were described and quantified using (n)UPLC-LTQ-Orbitrap. The datasets were analyzed employing an integrative statistical approach, which allowed the determination of the interactions between proteins and metabolites and the different bud sections and ages. Specific dynamics of proteins and metabolites such as histones H3 and H4, ribosomal proteins L15 and L12, chaperonin TCP1, 14-3-3 protein gamma, gibberellins A1, A3 and A8, strigolactones and abscisic acid, involved in epigenetic regulation, proteome remodeling, hormonal signaling and abiotic stress pathways showed their potential role during bud maturation. Candidates and pathways were validated employing interaction databases and targeted transcriptomics. These results increase our understanding of the molecular processes behind bud maturation, a key step towards improving timber production and natural pine forests management in a future scenario of climate change. However, further studies are necessary using different P. pinaster populations that show contrasting wood quality and stress tolerance in order to generalize the results.

Clar Goblet and Aromaticity Driven Multiradical Nanographenes.

The Clar Goblet, the first radical bowtie nanographene proposed by Erich Clar nearly 50 years ago, was recently synthesized. Bowtie nanographenes present quasi-degenerate magnetic ground states, which make them so elusive as unique. A thorough analysis is presented of the spin-state energetics of Clar Goblet and bowtie nanographenes by a battery of existing and novel ab initio procedures ranging from density functional theory to complete active space Hamiltonians. With this, it was proven that π radicals of bowtie nanographenes sit on BP (Benzo[cd]Pyrene) moieties driven by their local aromaticity, a purely chemical concept, which confers global stability to the whole structure. Besides, a novel Pauli energy densities analysis provided a visual intuitive explanation for this preference. These findings allow envisioning that analogous bowtie nanographenes with arbitrary polyradical character are not only feasible at the molecular scale but will share Clar Goblet's peculiar properties.

Distinct Helical Molecular Orbitals through Conformational Lock*.

Several theoretical studies have proposed strategies to generate helical molecular orbitals (Hel-MOs) in [n]cumulenes and oligoynes. While chiral even-[n] cumulenes feature Hel-MOs, odd-[n] cumulenes may also present them if the terminal groups lie in different planes. However, the proposed systems have been either experimentally unfeasible or resulted in opposite pseudo-degenerated Hel-MOs. We hereby demonstrate the introduction of a remarkable energy difference between helical orbitals of opposite twist by fixing the torsion angle between the terminal groups in butadiyne fragments. To experimentally lock the conformation of the terminal groups, we designed and synthesized cyclic architectures by combining acetylenes with chiral spirobifluorenes. The high stability of these systems with distinct helical orbitals allowed their isolation and full characterization. In our view, these results constitute a step further in the development of real systems presenting helical molecular orbitals.

Electrochemical biosensor for the simultaneous determination of rheumatoid factor and anti-cyclic citrullinated peptide antibodies in human serum.

This paper reports a dual electrochemical biosensor involving carboxylated- or neutravidin-functionalized magnetic microbeads and dual screen-printed carbon electrodes for the simultaneous determination of rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCPA) autoantibodies used as biomarkers for the detection of rheumatoid arthritis autoimmune disease. Sandwich-type biosensors involving Fc fragments of IgG Fc(IgG) and biotinylated cyclic cytrullinated peptide (CCP-biotin) to form CCP-biotin-Neutr-MBs for the specific immobilization of RF and CCPA, respectively, as well as conjugation with HRP-IgM and HRP-IgG for RF and CCPA, respectively, were prepared. Amperometric detection was performed at -0.20 V vs. Ag pseudo-reference electrode using the H2O2/hydroquinone (HQ) system upon capturing the bioconjugates onto the corresponding working electrode (WE1 or WE2) of SPCdEs. The dual biosensor exhibits high sensitivity for RF and CCPA with LOD values of 0.8 and 2.5 IU mL-1, respectively. The simultaneous determination can be completed in about two hours using a simple protocol and a sample volume (25 µL) four times smaller than that required by the ELISA method. The dual electrochemical biosensor was used for the determination of both target biomarkers in human serum.

Assessing the Reversed Exponential Decay of the Electrical Conductance in Molecular Wires: The Undeniable Effect of Static Electron Correlation.

An extraordinary new family of molecular junctions, inaccurately referred to as "anti-Ohmic" wires in the recent literature, has been proposed based on theoretical predictions. The unusual electron transport observed for these systems, characterized by a reversed exponential decay of their electrical conductance, might revolutionize the design of molecular electronic devices. This behavior, which has been associated with intrinsic diradical nature, is reexamined in this work. Since the diradical character arises from a near-degeneracy of the frontier orbitals, the employment of a multireference approach is mandatory. CASSCF calculations on a set of nanowires based on polycyclic aromatic hydrocarbons (PAHs) demonstrate that, in the frame of an appropriate multireference treatment, the ground state of these systems shows the expected exponential decay of the conductance. Interestingly, these calculations do evidence a reversed exponential decay of the conductance, although now in several excited states. Similar results have been obtained for other recently proposed candidates to "anti-Ohmic" wires. These findings open new horizons for possible applications in molecular electronics of these promising systems.