Towards understanding the first half-ALD cycle of Ag growth: adsorption and dissociation of silver(I) acetamidinates on the Ag(110) surface.

The advancement of atomic layer deposition (ALD) techniques for the controlled growth of transition metal thin films is constantly growing due to the design and synthesis of novel organometallic (OM) precursors capable of facilitating precise deposition and clean film growth. In this context, acetamidinates have emerged as a highly promising family of OM precursors due to their exceptional attributes, including outstanding stability, favorable volatility, and reactivity at low evaporation and deposition temperatures. These unique properties make them a sought-after candidate for enabling ALD processes. Here we conducted an atomic-scale study to get an in-depth understanding of the first ALD partial reaction, which involves the adsorption and dissociation process of the silver acetamidinate on the Ag(110) surface. Our research sheds light on the multistep adsorption and breaking mechanism of the novel silver(I)-N,N'-dimethylacetamidinate precursor employed as the silver source. Since the difference in energy between the monomer and dimer phases of the precursor is only 1.92 eV, we have explored the adsorption states of both phases. The monomer adsorbs on the surface by occupying hollow (H) sites; after that, it dissociates and loses its ligand, adopting a perpendicular geometry via the formation of new Ag-N bonds with the pair of N atoms at the top sites of the surface. On the other hand, the dimer adsorbs on long-bridge sites (LB) with the pair of N atoms occupying top sites with the silver atoms from the surface. Next, the dimer loses a pair of N-Ag bonds on each ligand, reaching a more stable state of partial cleavage with a relative energy of -0.38 eV. After overcoming an energy barrier of 0.41 eV, the dimer loses the remaining pair of N-Ag bonds, and the silver atoms diffuse towards H sites. Finally, the ligands diffuse toward the adjacent channel in the [100] direction of the surface. A charge distribution analysis of the adsorption stages shows the evolution of the silver atoms from precursor to the metallic state.

The effect of shape and size in the stability of triangular Janus MoSSe quantum dots.

Asymmetric Janus transition metal dichalcogenide MoSSe is a promising catalytic material due to the intrinsic in-plane dipole of its opposite faces. The atomic description of the structures observed by experimental techniques is relevant to tuning and optimizing its surface reaction processes. Furthermore, the experimentally observed triangular morphologies in MoSSe suggest that an analysis of the chemical environment of its edges is vital to understand its reactivity. Here we analyze the size-shape stability among different triangular structures-quantum- dots proposed from the ideal S(-1010) and Mo(10-10) terminations. Our stability analysis evidenced that the S-Se termination is more stable than Mo; moreover, as the size of the quantum dot increases, its stability increases as well. Besides, a trend is observed, with the appearance of elongated Mo-S/Se bonds at symmetric positions of the edges. Tersoff-Hamann scanning tunneling microscopy images for both faces of the stablest models are presented. Electrostatic potential isosurfaces denote that the basal plane on the S face of both configurations remains the region with more electron density concentration. These results point toward the differentiated activity over both faces. Finally, our study denotes the exact atomic arrangement on the edges of MoSSe quantum dots corresponding with the formation of S/Se dimers who decorates the edges and their role along with the faces as catalytic sites.

Differential reproductive responses to contrasting host species and localities in Psittacanthus calyculatus (Loranthaceae) mistletoes.

Host trees are immediate environments for multi-host mistletoes, so parasitizing different hosts implies exposure to varying environmental conditions between mistletoe generations. Therefore, to maximize reproductive fitness in heterogeneous environments (host species) mistletoes should adjust its reproductive responses in relation to circumstances. Here, we ask how reproductive traits of Psittacanthus calyculatus mistletoes vary on two host tree species (Crataegus mexicana, Prunus serotina) at three different localities. We followed individual mistletoes on each host species and at three localities through the flowering season to quantify traits related to reproductive effort and success, e.g. total number of buds, flowers and fruits produced. In buds about to open, we measured two anthers and quantified the number of pollen grains and their viability. Individual flowers were marked to obtain flower longevity data and were followed until fruit formation. At which time we measured and weighed the fruits and the seeds. Mistletoes from one locality produced more buds, flowers and fruits, and the flowers lasted longer, had larger anthers and produced more pollen as compared to the other two localities. However, mistletoes on Prunus serotina produced fewer floral buds, but their fruits were heaviest, longest and widest and ripened fastest across localities. The probability of fruit formation, percentage of fruits formed, and pollen viability were similar among the mistletoes, regardless of host species or locality. We propose that the observed differences in reproductive effort and success associated with host species or locality are plastic or adaptive in this mistletoe in response to varying conditions.

A first-principles study of the atomic layer deposition of ZnO on carboxyl functionalized carbon nanotubes: the role of water molecules.

The formation of heterostructures that combine a large surface area with high surface activity has attracted the attention of the scientific community due to the unique properties and applications of these heterostructures. In this work, we describe - at the atomic level - the full reaction mechanisms involved in the atomic layer deposition of a hybrid ZnO/CNT inorganic structure. First, the pristine CNTs are chemically activated with a carboxylic acid, a process unique to carbon materials. Diethylzinc (DEZ) and water are used as gas-phase precursors to form ZnO. Our findings show that DEZ is physically adsorbed on the CNTs during the exposure of the first precursor. The ligand-exchange to generate chemisorbed ethyl zinc on the O side of the COOH group needs to overcome an energy barrier of 0.06 eV. This is a very small energy if compared to the values (0.5-0.6 eV) obtained in previous studies for OH functionalized surfaces. The height of the barrier is associated with the C[double bond, length as m-dash]O side, which mediates the H proton's exchange from the OH group to the C2H5 ligand. Furthermore, upon exposure to the oxidizing agent (H2O), ethyl zinc exchanges its last ligand as ethane, and it accepts a hydroxyl group through a self-limiting reaction with an energy barrier of 0.88 eV. Notice that the energy barrier of the second ligand-exchange is larger than of the first. We have also analyzed the effect in the saturation of the second precursor: as the quantity of water molecules increases, the long-range interactions tend to repel them. However, the energy barrier of the second ligand-exchange decreases from 1.53 eV to 0.88 eV for one and two water molecules, showing a clear dependence on the oxidizing agent. Non-covalent interactions are used as a tool to visualize the driving forces that take place during each partial reaction in real space. Our study points out the importance of using the right functionalization agent to achieve a controlled and conformal ALD growth at the initial steps of the formation of hybrid ZnO/CNT structures, as well as the role played by the oxidizing agent to lower the energy barrier on the second ALD step.

Knowledge, attitudes, and practices about homelessness and willingness-to-pay for housing-first across 8 European countries: a survey protocol.

BACKGROUND: Most European countries report rising numbers of people experiencing homelessness. For those with mental disorders, interventions are centered on achieving mental health and drug rehabilitation alongside housing readiness, often to the detriment of access to housing. Notwithstanding, more European countries are investing in a new model, Housing First (HF), which postulates immediate access to permanent housing with no initial requirements for treatment. While results of the European HF programs are published on individual-level data, little is known about the opinions of the general population about homelessness and the societal value of the HF model, which can represent barriers to the model's dissemination. Therefore, we present the protocol of a study designed for the following objectives: 1) to explore the knowledge, attitudes, and practices (KAP) about homelessness within the general population of 8 European countries, 2) to assess the valuation of the HF model by European citizens, and 3) to estimate the lifetime prevalence of homelessness in the targeted countries. METHODS: A telephone survey was conducted from March to December 2017 among adults selected from opt-in panels from France, Ireland, Italy, the Netherlands, Portugal, Spain, Poland, and Sweden. A total sample of 5600 interviews was expected, with 700 per country. The interviews included three sections: first, the KAP about homelessness; second, the valuation of the HF model by measuring a respondent's willingness-to-pay (WTP) through the contingent valuation method; and third, an assessment of the lifetime prevalence of homelessness among the general population. Descriptive analyses and comparisons between countries will be conducted. KAP indicators will be created and their psychometric properties assessed. Determinants of WTP will be assessed through regression models. DISCUSSION: This survey will highlight Europeans' views of homelessness, especially their level of tolerance towards homelessness, potential misconceptions and the most important barriers for the implementation of the HF model. Additionally, the results on the valuation of the HF model by citizens could be instrumental for key stakeholders in understanding the level of support from the general population. Ethics approval has been obtained from the Aix-Marseille University Ethics Committee (n° 2016-01-02-01) for this study, which is part of HOME_EU: Reversing Homelessness in Europe H2O20-SC6-REVINEQUAL-2016/GA726997.

Use of the hCONSORT criteria as a reporting standard for herbal interventions for common dermatoses: a systematic review.

BACKGROUND: The use of complementary and alternative medicine (CAM) is increasing in Western countries, including in the area of dermatology. However, Western healthcare providers have not integrated CAM into regular practice owing to a lack of reliable data supporting its use. To encourage high-quality research related to the use of CAM and specifically herbal interventions, the CONsolidated Standards Of Reporting Trials (CONSORT) extension criteria on reporting herbal interventions (hCONSORT) were published in 2006. OBJECTIVES: To evaluate the adherence of randomized controlled trials (RCTs) investigating herbal interventions for acne, atopic dermatitis (AD) and psoriasis to the hCONSORT criteria. METHODS: A comprehensive search of the PubMed, Embase and Cochrane Library databases was conducted. RCTs published between 2009 and 2014 assessing therapeutic outcomes of plant-based interventions for acne, AD or psoriasis were included. Investigators determined the number of unique hCONSORT criteria satisfied per report. anova was used to examine differences in scores by disease entity. RESULTS: The vast majority of reviewed studies reported < 50% of information recommended in the hCONSORT criteria. Limitations include the small number of dermatological conditions examined, exclusion of reports based on language and lack of assessment of overall adherence to CONSORT criteria. CONCLUSIONS: Our data indicate lack of adherence to hCONSORT extension criteria. Adherence to hCONSORT guidelines should be encouraged in order to provide high-quality reporting of research on herbal interventions in dermatology. Doing so may ease the integration of CAM into conventional medical practice and provide actionable data to providers.

The Treatment of Neck Pain-Associated Disorders and Whiplash-Associated Disorders: A Clinical Practice Guideline

OBJECTIVE: The objective was to develop a clinical practice guideline on the management of neck pain-associated disorders (NADs) and whiplash-associated disorders (WADs). This guideline replaces 2 prior chiropractic guidelines on NADs and WADs. METHODS: Pertinent systematic reviews on 6 topic areas (education, multimodal care, exercise, work disability, manual therapy, passive modalities) were assessed using A Measurement Tool to Assess Systematic Reviews (AMSTAR) and data extracted from admissible randomized controlled trials. We incorporated risk of bias scores in the Grading of Recommendations Assessment, Development, and Evaluation. Evidence profiles were used to summarize judgments of the evidence quality, detail relative and absolute effects, and link recommendations to the supporting evidence. The guideline panel considered the balance of desirable and undesirable consequences. Consensus was achieved using a modified Delphi. The guideline was peer reviewed by a 10-member multidisciplinary (medical and chiropractic) external committee. RESULTS: For recent-onset (0-3 months) neck pain, we suggest offering multimodal care; manipulation or mobilization; range-of-motion home exercise, or multimodal manual therapy (for grades I-II NAD); supervised graded strengthening exercise (grade III NAD); and multimodal care (grade III WAD). For persistent (>3 months) neck pain, we suggest offering multimodal care or stress self-management; manipulation with soft tissue therapy; high-dose massage; supervised group exercise; supervised yoga; supervised strengthening exercises or home exercises (grades I-II NAD); multimodal care or practitioner's advice (grades I-III NAD); and supervised exercise with advice or advice alone (grades I-II WAD). For workers with persistent neck and shoulder pain, evidence supports mixed supervised and unsupervised high-intensity strength training or advice alone (grades I-III NAD). CONCLUSIONS: A multimodal approach including manual therapy, self-management advice, and exercise is an effective treatment strategy for both recent-onset and persistent neck pain

Reproductive biology and nectar production of the Mexican endemic Psittacanthus auriculatus (Loranthaceae), a hummingbird-pollinated mistletoe.

Many mistletoe species produce 'bird'-pollinated flowers; however, the reproductive biology of the majority of these species has not been studied. Psittacanthus auriculatus is a Mexican endemic mistletoe, most common in open, dry mesquite grassland. Knowledge of the reproductive biology of P. auriculatus is essential for understanding species formation and diversification of Psittacanthus mistletoes, but it is currently poorly understood. Thus, we studied floral biology and phenology, nectar production and breeding system and pollination of this species. The hermaphroditic red-pink flowers open from the middle to the tip and petals are curly, but remain partially fused forming a floral tube of ca. 20-mm long. Flowers are partially protandrous, produce large amounts of nectar, last 2 days, and stigma receptivity is highest during the second day. We recorded hummingbirds (Cynanthus latirostris, Hylocharis leucotis, Amazilia beryllina, A. violiceps, Calothorax lucifer, Archilochus colubris) and less commonly butterflies (Agraulis vanillae, Anteos clorinde, Papilio multicaudatus, Phocides urania, Phoebis sennae) as floral visitors. P. auriculatus flowers are self-compatible. However, this mistletoe is an obligate animal-pollinated species, as the sensitive stigma avoids self-pollination. Under natural conditions, reproductive success was higher than in manually selfed or cross-pollinated flowers, likely due to the traplining foraging behaviour of hummingbirds. We suggest that the apparent efficient foraging behaviour of hummingbirds maintains gene flow among P. auriculatus, promoting outcrossing.

Uncorrelated evolution between vocal and plumage coloration traits in the trogons: a comparative study.

The costs of bird song incurred in a diversity of ways may result in trade-offs in the production and maintenance of elaborate plumage ornaments. In this paper, we examine evolutionary trade-offs between acoustic and visual signalling in trogon birds (Trogonidae). Using multiple regressions with phylogenetically independent contrasts, we found that interspecific variation in male plumage coloration was not significantly predicted by song traits (reduced by PCA) or altitude. Although plumage coloration is expected to decrease with increases in song elaboration, both groups of variables were not related. Given that song and plumage coloration traits are likely targets of sexual selection, we also examined their relationships with sexual plumage dimorphism. We found that male carotenoid-derived coloration was positively related to sexual plumage dimorphism, suggesting that sexual selection on male carotenoid-derived coloration may be stronger than on melanin- or structurally based coloration, or than on acoustic traits. Comparative studies on other bird families accounting for the effects of phylogeny as well as environmental covariates are required to test the generality of our findings in trogons.

Phylogenetic analysis of interspecific variation in nectar of hummingbird-visited plants.

We tested whether phylogeny, flower size and/or altitude were significant predictors of interspecific variation in nectar production of hummingbird-visited plants in an assembled database (289 species, in 22 orders, 56 families and 131 genera). Although the study is focused on hummingbird-pollinated plants (241 plant species), plants with different pollinator syndromes (48 species) are also included in the analyses. Nectar volume secreted in a given time period (usually 24 h) by a given flower, its sugar concentration and corolla length were compiled mainly from the literature. Altitude was also obtained from the original references. Sugar production was computed basically as the product of nectar secretion and sugar concentration, and expressed on a per 24-h basis. All nectar traits and corolla length (all log transformed), as well as altitude, showed statistically significant phylogenetic signal. Both nonphylogenetic and phylogenetically informed (independent contrasts) analyses indicated a highly significant positive correlation between corolla length and both nectar volume and sugar production. In addition, altitude (which is partially a surrogate for temperature) was significantly negatively correlated with both sugar concentration and production. Possible reasons for coadaptation of nectar production and sugar production with corolla length are discussed.

Development of distylous flowers and investment of biomass in male and female function in Palicourea padifolia (Rubiaceae).

Knowledge of developmental pathways for achieving differences in style and anther heights, in concert with those of ancillary features accompanied with data in regard to biomass investment to male and female function, provide an excellent opportunity for examining the developmental correlations between primary and ancillary floral traits so as to understand the evolution of heterostyly. The ontogenetic relationships between bud length and anther height and between bud length and style height, and between bud length versus bud width, anther length, and number of pollen grains per anther for long-styled (LS) and short-styled (SS) morphs of P. PADIFOLIA are described. We also described the ontogenetic biomass allocation to male and female function and to corolla with elongation of buds harvested at regular intervals. We observed an early termination of stylar growth in SS buds, whereas LS styles steadily increased in size. Morph differences for relative growth rates were significant for anther height, anther length, and pollen number but not for bud width. Bud width and anther length had a negative allometric relationship with bud elongation. The relationship between bud length and number of pollen grains per anther was positive and morph differences in pollen number were detected at later stages of development. An increase in corolla mass involved a disproportionate allocation to the female function in SS flowers and male allocation was similar for the two morphs over the course of development. Our results are consistent with theoretical and empirical data for distylous species with an approach herkogamous ancestor, and with the more general hypothesis of ontogenetic lability of heterostyly, in which morph differences in style and anther heights are achieved in various ways. Variations observed in sexual investment between floral morphs suggest differences in sex expression during flower development.

Mojave rattlesnakes (Crotalus scutulatus scutulatus) lacking the acidic subunit DNA sequence lack Mojave toxin in their venom.

The venom composition of Mojave rattlesnakes (Crotalus scutulatus scutulatus) differs in that some individuals have Mojave toxin and others do not. In order to understand the genetic basis for this difference, genomic DNA samples from Mojave rattlesnakes collected in Arizona, New Mexico, and Texas were analyzed for the presence of DNA sequences that relate to the acidic (Mta) and basic (Mtb) subunits of this toxin. DNA samples were subjected to PCR to amplify nucleotide sequences from second to fourth exons of the acidic and basic subunits. These nucleotide sequences were cloned and sequenced. The nucleotide sequences generated aligned exactly to previously published nucleotide sequences of Mojave toxin. All DNA samples analyzed generated product using the basic subunit primers, and aligned identically to the Mtb nucleotide sequence. However, only 11 out of the 14 samples generated a product with the acidic subunit primers. These 11 sequences aligned identically to the Mta nucleotide sequence. The venom from the three snakes whose DNA did not amplify with the acidic subunit primers were not recognized by antibodies to Mojave toxin. This suggests that snakes with venom lacking Mojave toxin also lack the productive nucleotide sequence for the acidic subunit in their DNA.

[Anxiety and depression among renal transplantation candidates: impact of donor availability]. / Ansiedad y depresión en candidatos a trasplante renal: impacto de la disponibilidad de donador.

BACKGROUND: Among the kidney transplantation candidates, regardless if they already have a living related donor (LRD) or if they are waiting for a cadaveric donor (CD), the transplantation process is highly stressful, and the stress intensity is proportioned to the waiting time for surgery. The patients waiting for a CD have no certainty about receiving a kidney in time for surviving, or, when the patient's relatives refused the donation, they may feel rejected by their family. In chronic diseases, psychiatric comorbidity affects the disease evolution, dampering the treatment efficacy, leading to long-term hospitalizations and a more severe emotional stress. OBJECTIVE: To calculate the difference of anxiety and depression levels between LRD and CD patients. METHODS: The Hospital Anxiety and Depression scale (HAD) was applied to the kidney transplantation candidates who attended their first psychiatric evaluation along a year, they were grouped according to their kind of donor (LRD= 31, CD= 12). Statistical analysis was performed by means of Fisher and Mann-Whitney tests. RESULTS: 33.33% of the LRD patients were anxious (6.60+/- 2.65 points) and 40% were depressed (5.9+/- 3.29); 75% of the CD patients were anxious (p= 0.005) (10.17+/- 2.48, p< 0.001) and 90% were depressed (p= 0.088) (12.0+/- 9.33, p= 0.005). CONCLUSIONS: The CD patients have a greater risk for anxiety and more severe depressive disorders than the LRD patients. Comparing this sample against 100 patients with chronic diseases, we found no differences with CD patients, but they have a higher risk for anxiety and depression than LRD patients, this may suggest that the last mentioned patients may overestimate the prognosis of their disease.

Ansiedad y depresión en candidatos a trasplante renal: impacto de la disponibilidad de donador / Anxiety and depression among renal transplantation candidates: impact of donor availability

Introducción: Entre los candidatos a trasplante renal, independientemente de que dispongan un donador vivo relacionado (DVR) o esperen un donador cadavérico (DC), el proceso del trasplante produce un estrés intenso, el cual es proporcional al tiempo de espera para la cirugía. Quienes esperan DC no tienen la certeza de obtener un órgano a tiempo para sobrevivir, o bien, cuando sus parientes se niegan a donar, los enfermos sienten ser rechazados por su familia. En enfermedades crónicas, la comorbilidad psiquiátrica afecta la evolución del padecimiento y reduce la eficacia del tratamiento, llevando a internamientos largos y a un mayor desgaste emocional. Objetivo: Determinar la diferencia de niveles de ansiedad y depresión en pacientes de DC en comparación a los pacientes con DVR. Metodología: Se aplicó la escala hospitalaria de ansiedad y depresión (HAD) a los candidatos a trasplante renal que acudieron a su primer consulta psiquiátrica a lo largo de un año, agrupándose de acuerdo al donador que disponen (DVR= 31, DC= 12). El análisis estadístico se realizó mediante las pruebas de Fisher y de Mann-Whitney. Resultados: El 33,33 por ciento de los pacientes con DVR presentaron ansiedad (6,60ñ 2,65 puntos) y 40 por ciento depresión (5,9ñ 3,29); el 75 por ciento de los pacientes de DC mostraron ansiedad (p= 0,005) (10,17ñ 2,48, p< 0,001) y 90 por ciento depresión (p= 0,088) (12,0ñ 9,33, p= 0,005). Conclusiones: Los pacientes de DC tienen mayor riesgo de padecer ansiedad que los enfermos con DVR y sufren cuadros depresivos más severos. Comparando esta muestra contra 100 enfermos crónicos, no encontramos diferencias con los pacientes de DC, pero sí tienen mayor riesgo de ansiedad y depresión que los pacientes con DVR, lo cual indicaría que estos últimos enfermos pudieran tener ideas sobrevaloradas sobre la evolución de su enfermedad (AU)