Single-Spin Sensing: A Molecule-on-Tip Approach.

Magnetometry plays a pivotal role in addressing the requirements of ultradense storage technology and overcoming challenges associated with downscaled spin qubits. A promising approach for atomic-scale single-spin sensing involves utilizing a magnetic molecule as a spin sensor, although such a realization is still in its early stages. To tackle this challenge and underscore the potential of this method, we combined a nickelocene molecule with scanning tunneling microscopy to perform versatile spin-sensitive imaging of magnetic surfaces. We investigated model Co islands on Cu(111) of different thicknesses having variable magnetic properties. Our method demonstrates robustness and reproducibility, providing atomic-scale sensitivity to spin polarization and magnetization orientation, owing to a direct exchange coupling between the nickelocene-terminated tip and the Co surfaces. We showcase the accessibility of magnetic exchange maps using this technique, revealing unique signatures in magnetic corrugation, which are well described by computed spin-density maps. These advancements significantly improve our capacity to probe and visualize magnetism at the atomic level.

Entre science et engagement : les défis de la recherche communautaire au sein du réseau Coalition PLUS.

Community-based research, that is, the meaningful involvement of affected populations in the production of scientific knowledge that concerns them, is a political struggle and an ethical necessity. Coalition PLUS, an international network of organizations (most of them NGOs) fighting against HIV and hepatitis, created a community-based research laboratory (CBRL) composed of people from more than sixteen countries and various disciplinary fields. The objectives of the CBLR are to build research capacity, ensure collaboration with local and international academic research centers, and develop international research projects. The CBRL acts as a bridge between different partners, reconciling sometimes divergent interests, and must provide mediation and support to promote dialogue, transparency, and a relationship of trust between the communities and academic researchers. However, the need for scientific legitimacy obliges us to continuously seek a balance between responding to the needs of the field and using rigorous scientific methods, while optimizing and prioritizing existing resources. The permanent quest for this balance has led the CBRL to reorganize its mode of operation to optimize existing synergies with academic research laboratories, with a view to asserting its scientific legitimacy and continuing to contribute to social transformation through community-based research that is both innovative and of high quality. This paper provides a critical reflection on the issues, challenges, practices, and solutions of community-based research within the Coalition PLUS network.

Impact of the COVID-19 Health Crisis on Key Populations at Higher Risk for, or Living With, HIV or Hepatitis C Virus and People Working With These Populations: Multicountry Community-Based Research Study Protocol (EPIC Program).

BACKGROUND: Information concerning the impact of the COVID-19 health crisis on populations most affected by HIV and hepatitis C virus (HCV; or key populations [KP]), and those working with these populations in community settings, is limited. Community-based organizations working in the field of HIV and viral hepatitis are well placed to identify and meet the new needs of KP owing to the health crisis. OBJECTIVE: This study aims to describe the development and implementation of an exploratory and descriptive multicountry, community-based research program, EPIC (Enquêtes Pour évaluer l'Impact de la crise sanitaire covid en milieu Communautaire), within an international network of community-based organizations involved in the response to HIV and viral hepatitis. The EPIC program aimed to study the impact of the COVID-19 health crisis on KP or people living with HIV or HCV and people working with these populations at the community level (community health workers [CHWs]) and to identify the key innovations and adaptations in HIV and HCV services. METHODS: A general protocol and study documents were developed and shared within the Coalition PLUS network. The protocol had a built-in flexibility that allowed participating organizations to adapt the study to local needs in terms of the target population and specific themes of interest. Data were collected using surveys or interviews. RESULTS: From July 2020 to May 2022, a total of 79 organizations participated in the EPIC program. Across 32 countries, 118 studies were conducted: 66 quantitative (n=12,060 among KP or people living with HIV or people living with HCV and n=811 among CHWs) and 52 qualitative (n=766 among KP or people living with HIV or people living with HCV and n=136 among CHWs). CONCLUSIONS: The results of the EPIC program will provide data to describe the impact of the health crisis on KP and CHWs and identify their emerging needs. Documentation of innovative solutions that were put into place in this context may help improve the provision of services after COVID-19 and for future health crises. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/45204.

Resilience outcomes and associated factors among workers in community-based HIV care centres during the Covid-19 pandemic: A multi-country analysis from the EPIC program.

Introduction: Community health workers (CHW) were integral in the COVID-19 response, particularly concerning services for populations vulnerable to HIV. Little is known regarding the mental health of CHW during the COVID-19 crisis. The objective of this study was to study resilience of CHW working in HIV non-governmental organizations. Methods: An anonymous online, cross-sectional questionnaire was implemented during 2021 among CHW in Benin, Colombia, Guatemala, and Spain. Three scales were used to assess mental health: the 6-item Brief-Resilience Scale, the 9-item Patient Scale Questionnaire and the 7-item Generalized-Anxiety-Disorder scale. Logistic regression models were used to identify factors associated with "low" resilience vs "normal" or "high" resilience. Results: Among 295 respondents, the median standardized resilience score was 58.33 (IQR = [50.0-75.0], n = 267), 18.52 (IQR = [7.4-33.3], n = 282) for standardized depression score and 19.05 (IQR = [4.8-33.3], n = 274) for standardized anxiety score. Standardized resilience score was negatively correlated with standardized anxiety score (rho = -0.49, p < 0.001, n = 266) and standardized depression score (rho = -0.44, p < 0.001, n = 267). Conclusions: Normal or high level of resiliency in the HIV CHW were observed during the COVID-19 crisis. Self-efficacy, through COVID-19 prevention training, was a factor associated with resilience. Health policy must place CHW at the core of the healthcare system response to Covid-19 and to future health emergencies, as they ensure continuity of care for many diseases including HIV among vulnerable populations.

Sotos Syndrome and Nephrocalcinosis, a Rare But Possible Association due to Impact on Contiguous Genes.

One-month old breastfeeding infant, full-term birth, with normal anthropometric measurements at birth is referred to Pediatric Nephrology due to a nephrocalcinosis. The patient presents dysmorphic features and heart disease. A metabolic study is conducted on blood and urine yielding results within normal parameters, except for renal concentration test and acidification test. At 6 months of age, patient presents overgrowth, which along with other clinical signs arouse suspicion of Sotos Syndrome. Molecular genetic testing detects heterozygous deletion in 5q35 between bands q35.2 and q35.3, affecting genes NSD1, SLC34A1 and FGFR4, which is compatible with this syndrome and with nephrocalcinosis as a rare association.

Large Orbital Moment of Two Coupled Spin-Half Co Ions in a Complex on Gold.

The magnetic properties of transition-metal ions are generally described by the atomic spins of the ions and their exchange coupling. The orbital moment, usually largely quenched due the ligand field, is then seen as a perturbation. In such a scheme, S = 1/2 ions are predicted to be isotropic. We investigate a Co(II) complex with two antiferromagnetically coupled 1/2 spins on Au(111) using low-temperature scanning tunneling microscopy, X-ray magnetic circular dichroism, and density functional theory. We find that each of the Co ions has an orbital moment comparable to that of the spin, leading to magnetic anisotropy, with the spins preferentially oriented along the Co-Co axis. The orbital moment and the associated magnetic anisotropy is tuned by varying the electronic coupling of the molecule to the substrate and the microscope tip. These findings show the need to consider the orbital moment even in systems with strong ligand fields. As a consequence, the description of S = 1/2 ions becomes strongly modified, which have important consequences for these prototypical systems for quantum operations.

Chemsex in Barcelona: A qualitative study of factors associated with the practice, the perception of the impact on health and prevention needs. / Chemsex en Barcelona: Estudio cualitativo sobre factores asociados a la práctica, percepción del impacto en salud y necesidades de prevención.

Chemsex is defined as use of psychoactive drugs with the aim of having sexual relations between gay men, bisexuals and men who have sex with men for a long period of time. To study this phenomenon, this qualitative descriptive study was proposed with the objective of describing the practice of chemsex from the perspective of users, to determine the main factors associated with its practice, the perception of the impact on their health and to establish prevention needs. Data were obtained using conversational techniques: 12 semi-structured interviews and 3 focus groups. The purposive sample was made up of GBMSM with a mean age of 40.1 years, 78% born in Spain, and 68% with completed university studies. The qualitative analysis focused on three thematic areas: factors associated with the practice of chemsex, the impact of chemsex on health, and prevention and risk reduction needs. It is concluded that the practice of chemsex should be understood as multifactorial and multicausal, associated with the sociocultural context. Sexual satisfaction, increased libido and the search for more intense pleasure are identified as key factors among people who practice it. These men are still scared of being judged, even by specialists who may lack knowledge or training. A reanalysis and rethinking of the interventions and policies directed towards this population is necessary, putting the focus of action on shared decision-making, self-care, cultural competence and the humanization of care.

El chemsex se define como el uso de drogas psicoactivas con el objetivo de mantener relaciones sexuales entre hombres gay, bisexuales y otros hombres que tienen sexo con hombres (GBHSH), por un largo periodo de tiempo. El objetivo de este estudio cualitativo exploratorio es describir la práctica del chemsex desde la perspectiva de los usuarios, determinar los principales factores asociados a su práctica, la percepción del impacto en su salud y establecer necesidades de prevención. Se obtuvieron los datos mediante técnicas conversacionales: 12 entrevistas semiestructuradas y 3 grupos focales. El análisis cualitativo se centró en tres áreas temáticas: factores asociados a la práctica de chemsex, impacto del chemsex en la salud y necesidades prevención y reducción de riesgos. La muestra intencionada fue conformada por hombres GBHSH con una edad media de 40,1 años, 78% nacidos en España, y 68% con estudios universitarios finalizados. Los resultados del estudio ponen de manifiesto que la práctica de chemsex debe comprenderse como multifactorial y multicausal, y asociada al contexto sociocultural. La satisfacción sexual, del aumento de la libido y de la búsqueda de placer más intenso se identifican como factores clave entre las personas que lo practican. Sigue existiendo miedo en estos hombres a ser juzgados, incluso por los especialistas que pueden carecer de conocimiento o formación. Es necesario un reanálisis y replanteamiento de las intervenciones y políticas dirigidas hacia esta población, poniendo el foco de acción en la toma de decisiones compartidas, el autocuidado, la competencia cultural y la humanización del cuidado.

Thioetherification of Br-Mercaptobiphenyl Molecules on Au(111).

Thioether polymers are fundamental for a variety of applications. Their synthesis is, however, more challenging than that of other metal-catalyzed reactions due to the reported detachment of the S atom during thermal activation. In this study, it has been demonstrated unambiguously that thermal annealing results in the thioetherification of the 4-bromo-4-mercaptobiphenyl molecule (Br-MBP) adsorbed on the surface of Au(111). Through complementary techniques, such as scanning tunneling microscopy, spectroscopy, and first-principle calculations, we have identified four reaction steps, involving sulfhydryl or bromine molecular functional groups and leading to the formation of intermolecular C-S bonds. To form the thioether polymer and to overcome the competitive formation of C-C bonds, two reaction steps, the dehalogenation, and dissociation of the S-Au bond, must occur simultaneously. We detail the electronic properties of the phenyl-sulfur bond and the polymer as a function of the ligand length. This result suggests a wider perspective of this chemical synthesis.

A Nanocar and Rotor in One Molecule.

Depending on its adsorption conformation on the Au(111) surface, a zwitterionic single-molecule machine works in two different ways under bias voltage pulses. It is a unidirectional rotor while anchored on the surface. It is a fast-drivable molecule vehicle (nanocar) while physisorbed. By tuning the surface coverage, the conformation of the molecule can be selected to be either rotor or nanocar. The inelastic tunneling excitation producing the movement is investigated in the same experimental conditions for both the unidirectional rotation of the rotor and the directed movement of the nanocar.

Latin American Internet Survey for Men who have Sex with Men (LAMIS-2018): Design, methods and implementation.

Despite men-who-have-sex-with-men (MSM) from Latin America (LA) are still a vulnerable population for known health-related conditions and social problems, availability of comparable data across LA countries for assessment and monitoring purposes is limited. The objective of this article is to present the study design and the questionnaire of LAMIS-2018 (Latin America MSM Internet Survey), its recruitment strategy, rates and sources by country, and the lessons learned from its implementation. LAMIS-2018 was a cross-sectional, internet-based survey targeting MSM living in 18 LA countries (Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname, Uruguay, and Venezuela) that gathered data about sexual behaviors, HIV/STI and viral hepatitis knowledge, prophylactic use of antiretrovirals, psychosocial health, and access to sexual health services. The survey went online for four months and was available in three languages (Spanish, Portuguese, and Dutch). Promotion was carried out using dating apps, websites, social networks, and by community-based and academic organizations of each participating country directly in gay venues and in their own premises. Overall, 64,655 MSM participated in LAMIS-2018. Dating apps and websites were the most important recruitment source in most countries, except for Honduras, Nicaragua, and Suriname, where community-based organizations recruited most of the participants. Beyond the LAMIS-2018 implementation description, we highlight the feasibility of such a study in this context, based on the collaboration between community-based and academic organizations to obtain a large sample of MSM in the region. LAMIS-2018 data will contribute to identify determinants of risk behaviors and prevention needs of vulnerable MSM populations in each country of the region.

La recherche communautaire en temps de pandémie : retour sur l'étude multi-pays EPIC.

In 2020, the COVID-19 health crisis affected all regions of the world, not sparing people already vulnerable to other viral epidemics such as HIV or HCV and/or those in precarious or socially marginalized situations. This is particularly the case for drug users or sex workers.Coalition PLUS, a network of associations fighting against HIV and viral hepatitis which defends and promotes the community-based approach, and its partners, have set up a multi-country community-based research project aimed at documenting the impact of the health crisis on the fight against HIV and viral hepatitis (key populations and community workers/activists), as well as the community responses put in place (EPIC survey).The objective of this paper is to reflect on the implementation of this community-based research study during the COVID-19 health crisis, and in particular the unforeseen difficulties to which the community-based research process had to confront and adapt. The goal is to draw lessons on what worked (and what did not work) in order to capitalize on community-based research practices during this pandemic and subsequently, facilitate the implementation of new research projects in similar contexts.

Electron Paramagnetic Resonance of Alkali Metal Atoms and Dimers on Ultrathin MgO.

Electron paramagnetic resonance (EPR) can provide unique insight into the chemical structure and magnetic properties of dopants in oxide and semiconducting materials that are of interest for applications in electronics, catalysis, and quantum sensing. Here, we demonstrate that EPR in combination with scanning tunneling microscopy (STM) allows for probing the bonding and charge state of alkali metal atoms on an ultrathin magnesium oxide layer on a Ag substrate. We observe a magnetic moment of 1 µB for Li2, LiNa, and Na2 dimers corresponding to spin radicals with a charge state of +1e. Single alkali atoms have the same charge state and no magnetic moment. The ionization of the adsorbates is attributed to charge transfer through the oxide to the metal substrate. Our work highlights the potential of EPR-STM to provide insight into dopant atoms that are relevant for the control of the electrical properties of surfaces and nanodevices.

Magnetic Interplay between π-Electrons of Open-Shell Porphyrins and d-Electrons of Their Central Transition Metal Ions.

Magnetism is typically associated with d- or f-block elements, but can also appear in organic molecules with unpaired π-electrons. This has considerably boosted the interest in such organic materials with large potential for spintronics and quantum applications. While several materials showing either d/f or π-electron magnetism have been synthesized, the combination of both features within the same structure has only scarcely been reported. Open-shell porphyrins (Pors) incorporating d-block transition metal ions represent an ideal platform for the realization of such architectures. Herein, the preparation of a series of open-shell, π-extended Pors that contain magnetically active metal ions (i.e., CuII , CoII , and FeII ) through a combination of in-solution and on-surface synthesis is reported. A detailed study of the magnetic interplay between π- and d-electrons in these metalloPors has been performed by scanning probe methods and density functional theory calculations. For the Cu and FePors, ferromagnetically coupled π-electrons are determined to be delocalized over the Por edges. For the CoPor, the authors find a Kondo resonance resulting from the singly occupied CoII dz 2 orbital to dominate the magnetic fingerprint. The Fe derivative exhibits the highest magnetization of 3.67 µB (S≈2) and an exchange coupling of 16 meV between the π-electrons and the Fe d-states.

Power discontinuity and shift of the energy onset of a molecular de-bromination reaction induced by hot-electron tunneling.

Understanding the mechanism of molecular dissociation under applied bias is a fundamental requirement to progress in (electro)-catalysis as well as in (opto)-electronics. The working conditions of a molecular-based device and the stability of chemical bonds can be addressed in metal-organic junctions by injecting electrons in tunneling conditions. Here, we have correlated the energy of de-bromination of an aryl group with its density of states in a self-assembled dimeric structure of 4'-bromo-4-mercaptobiphenyl adsorbed on a Au(111) surface. We have observed that the electron-energy range where the molecule is chemically stable can be extended, shifting the bias threshold for the rupture of the -C-Br bond continuously from about 2.4 to 4.4 V by changing the electron current. Correspondingly, the power needed for the dissociation drops sharply at 3.6 V, identifying different reaction regimes and the contribution of different molecular resonance states.

Doublet-Singlet-Doublet Transition in a Single Organic Molecule Magnet On-Surface Constructed with up to 3 Aluminum Atoms.

Starting from a long aza-starphene neutral and nonmagnetic organic molecule, a single-molecule magnet is on-surface constructed using up to 3 light nonmagnetic aluminum (Al) atoms. Seldom observed in solution with transition-metal atoms and going from 1 to 3 Al coordinated atoms, the doublet-singlet-doublet transition is easily on-surface accessible using the scanning tunneling microscope single-atom and single-molecule manipulations on a gold(111) surface. With 3 coordinated Al atoms, the lateral vibration modes of the Al3-aza-starphene molecule magnet are largely frozen. Using the Kondo states, this opens the observation of the in-phase Al vertical atom vibrations and out-of-phase central phenyl vibrations.

One-way rotation of a chemically anchored single molecule-rotor.

We present the chemical anchoring of a DMBI-P molecule-rotor to the Au(111) surface after a dissociation reaction. At the temperature of 5 K, the anchored rotor shows a sequential unidirectional rotational motion through six defined stations induced by tunneling electrons. A typical voltage pulse of 400 mV applied on a specific location of the molecule causes a unidirectional rotation of 60° with a probability higher than 95%. When the temperature of the substrate increases above 20 K, the anchoring is maintained and the rotation stops being unidirectional and randomly explores the same six stations. Density functional theory simulations confirm the anchoring reaction. Experimentally, the rotation shows a clear threshold at the onset of the C-H stretch manifold, showing that the molecule is first vibrationally excited and later it decays into the rotational degrees of freedom.

Bottom-up Fabrication and Atomic-Scale Characterization of Triply Linked, Laterally π-Extended Porphyrin Nanotapes*.

Porphyrin nanotapes (Por NTs) are promising structures for their use as molecular wires thanks to a high degree of π-conjugation, low HOMO-LUMO gaps, and exceptional conductance. Such structures have been prepared in solution, but their on-surface synthesis remains unreported. Here, meso-meso triply fused Por NTs have been prepared through a two-step synthesis on Au(111). The diradical character of the on-surface formed building block PorA2 , a phenalenyl π-extended ZnII Por, facilitates intermolecular homocoupling and allows for the formation of laterally π-extended tapes. The structural and electronic properties of individual Por NTs are addressed, both on Au(111) and on a thin insulating NaCl layer, by high-resolution scanning probe microscopy/spectroscopy complemented by DFT calculations. These Por NTs carry one unpaired electron at each end, which leads to magnetic end states. Our study provides a versatile route towards Por NTs and the atomic-scale characterization of such tapes.

Challenges in the synthesis of corannulene-based non-planar nanographenes on Au(111) surfaces.

The on-surface synthesis of non-planar nanographenes is a challenging task. Herein, with the aid of bond-resolving scanning tunneling microscopy (BRSTM) and density functional theory (DFT) calculations, we present a systematic study aiming at the fabrication of corannulene-based nanographenes via intramolecular cyclodehydrogenation on a Au(111) surface. The formation of non-planar targeted products is confirmed to be energetically unfavorable compared to the formation of planar/quasi-planar undesired competing monomer products. In addition, the activation of intermolecular coupling further inhibits the formation of the final targeted product. Although it was not possible to access the corannulene moiety by means of on-surface synthesis, partial cyclodehydrogenation of the molecular precursors was demonstrated.

Superconducting Scanning Tunneling Microscope Tip to Reveal Sub-millielectronvolt Magnetic Energy Variations on Surfaces.

Combining the complex ordering ability of molecules with their local magnetic properties is a little-explored technique to tailor spin structures on surfaces. However, revealing the molecular geometry can be demanding. Nickelocene (Nc) molecules present a large spin-flip excitation leading to clear changes of conductance at the excitation-threshold bias. Using a superconducting tip, we have the energy resolution to detect small shifts of the Nc spin-flip excitation thresholds, permitting us to reveal the different individual environments of Nc molecules in an ordered layer. This knowledge allows us to reveal the adsorption configuration of a complex molecular structure formed by Nc molecules in different orientations and positions. As a consequence, we infer that Nc layers present a strong noncollinear magnetic-moment arrangement.