Basic Mechanisms Research Articles

Regulation of laser-induced nanogratings by tuning the Marangoni-plasmon-coupled effect.

Laser-induced subwavelength nanogratings on films find widespread applications in enhancing a spectrum through surface plasmon excitation. It is challenging to achieve high uniformity, diversity, and controllability due to the intricate interplay between two basic mechanisms in laser nanostructuring: the Marangoni effect and surface plasmon polaritons (SPPs). We tune the coupled effect on Ge2Sb2Te5 films by adjusting the laser polarization, whose component controls the two effects' strength ratio. The Marangoni effect dominates when the SPPs' direction mismatches with the growing direction of nanogratings. Tuning this competition relationship helps to create nanogratings with tunable duty cycle and distribution, which are significant for light modulation applications. A highly efficient direct writing method with a line-shaped laser beam is employed to create large-area regular nanogratings by enhancing the effect tuning. We demonstrate diverse Au nanogratings with the aid of a lift-off operation and apply them in surface plasmon-coupled emission (SPCE), showcasing exceptional enhancement and narrowing performance.

PIAS family in cancer: from basic mechanisms to clinical applications.

Protein inhibitors of activated STATs (PIAS) are proteins for cytokine signaling that activate activator-mediated gene transcription. These proteins, as versatile cellular regulators, have been described as regulators of approximately 60 proteins. Dysregulation of PIAS is associated with inappropriate gene expression that promotes oncogenic signaling in multiple cancers. Multiple lines of evidence have revealed that PIAS family members show modulated expressions in cancer cells. Most frequently reported PIAS family members in cancer development are PIAS1 and PIAS3. SUMOylation as post-translational modifier regulates several cellular machineries. PIAS proteins as SUMO E3 ligase factor promotes SUMOylation of transcription factors tangled cancer cells for survival, proliferation, and differentiation. Attenuated PIAS-mediated SUMOylation mechanism is involved in tumorigenesis. This review article provides the PIAS/SUMO role in the modulation of transcriptional factor control, provides brief update on their antagonistic function in different cancer types with particular focus on PIAS proteins as a bonafide therapeutic target to inhibit STAT pathway in cancers, and summarizes natural activators that may have the ability to cure cancer.

Wasserstein Differential Privacy

Differential privacy (DP) has achieved remarkable results in the field of privacy-preserving machine learning. However, existing DP frameworks do not satisfy all the conditions for becoming metrics, which prevents them from deriving better basic private properties and leads to exaggerated values on privacy budgets. We propose Wasserstein differential privacy (WDP), an alternative DP framework to measure the risk of privacy leakage, which satisfies the properties of symmetry and triangle inequality. We show and prove that WDP has 13 excellent properties, which can be theoretical supports for the better performance of WDP than other DP frameworks. In addition, we derive a general privacy accounting method called Wasserstein accountant, which enables WDP to be applied in stochastic gradient descent (SGD) scenarios containing subsampling. Experiments on basic mechanisms, compositions and deep learning show that the privacy budgets obtained by Wasserstein accountant are relatively stable and less influenced by order. Moreover, the overestimation on privacy budgets can be effectively alleviated. The code is available at https://github.com/Hifipsysta/WDP.

Structures of LIG1 provide a mechanistic basis for understanding a lack of sugar discrimination against a ribonucleotide at the 3'-end of nick DNA

Human DNA ligase 1 (LIG1) is the main replicative ligase that seals Okazaki fragments during nuclear replication and finalizes DNA repair pathways by joining DNA ends of the broken strand breaks in the three-steps of ligation reaction. LIG1 can tolerate the RNA strand at the upstream of the nick, yet an atomic insight into the sugar discrimination mechanism by LIG1 against a ribonucleotide at the 3'-terminus of nick DNA is unknown. Here, we determined X-ray structures of LIG1/3'-RNA-DNA hybrids and captured the ligase during pre- and post-step 3 the ligation reaction. Furthermore, the overlays of 3'-rA:T and 3'-rG:C step 3 structures with step 2 structures of canonical 3'-dA:T and 3'-dG:C uncover a network of LIG1/DNA interactions through Asp570 and Arg871 side chains with 2'-OH of the ribose at nick showing a final phosphodiester bond formation and the other ligase active site residues surrounding the AMP site. Finally, we demonstrated that LIG1 can ligate the nick DNA substrates with preinserted 3'-ribonucleotides as efficient as Watson-Crick base-paired ends in vitro. Together, our findings uncover a novel atomic insight into a lack of sugar discrimination by LIG1 and the impact of improper sugar on the nick sealing of ribonucleotides at the last step of DNA replication and repair.

T2MAC: Targeted and Trusted Multi-Agent Communication through Selective Engagement and Evidence-Driven Integration

Communication stands as a potent mechanism to harmonize the behaviors of multiple agents. However, existing work primarily concentrates on broadcast communication, which not only lacks practicality, but also leads to information redundancy. This surplus, one-fits-all information could adversely impact the communication efficiency. Furthermore, existing works often resort to basic mechanisms to integrate observed and received information, impairing the learning process. To tackle these difficulties, we propose Targeted and Trusted Multi-Agent Communication (T2MAC), a straightforward yet effective method that enables agents to learn selective engagement and evidence-driven integration. With T2MAC, agents have the capability to craft individualized messages, pinpoint ideal communication windows, and engage with reliable partners, thereby refining communication efficiency. Following the reception of messages, the agents integrate information observed and received from different sources at an evidence level. This process enables agents to collectively use evidence garnered from multiple perspectives, fostering trusted and cooperative behaviors. We evaluate our method on a diverse set of cooperative multi-agent tasks, with varying difficulties, involving different scales and ranging from Hallway, MPE to SMAC. The experiments indicate that the proposed model not only surpasses the state-of-the-art methods in terms of cooperative performance and communication efficiency, but also exhibits impressive generalization.

Decreasing alpha flow releases task-specific processing paths

Abstract Directing and maintaining attention toward relevant information and away from non-relevant information is a critical competence of higher-order nervous systems. Here, we used directed connectivity to investigate how the human brain prioritizes appropriate processing paths when participants are performing a behavioral task requiring attention in the visual or the auditory modality. We show that the efficient transfer of information relevant for the task is mediated by a region- and task-specific decrease of alpha band connectivity from the parietal and, in case a motor response is required, motor cortex to the relevant sensory cortices. Further, alpha-band connectivity modulations reliably predict alpha power modulations in the task-related sensory cortices, particularly where the task-irrelevant cortex is inhibited via local alpha power increases. We suggest that the task- and region-specific modulation of alpha-band connectivity in the present study is a basic neuronal mechanism orchestrating the allocation of task-relevant neuronal resources related to and possibly underlying the previously reported sensory alpha power modulations in association with the allocation of competing attentional resources.

Abstract 4388: Tumor-associated RhoA mutants interact with effectors in both GDP- and GTP-bound states

Abstract RhoA is the founding member of the Ras-homology (Rho) small GTPase family and is a master regulator for multiple cell functions. Recurrent RhoA mutations have been identified in several human cancers, particularly in leukemia/lymphoma and gastric cancer. Intriguingly, both gain-of-function and loss-of-function mutations of RhoA are present, suggesting that RhoA GTPase may have a more sophisticated role in cancer and requires more rigorous investigations. Here, we have focused on two of the gain-of-function RhoA mutations identified in Adult T cell Leukemia/lymphoma (ATLL) at residue A161 (A161P and A161V) and aim to reveal the underlying mechanistic basis for their function by biochemical and structural analyses. We found that in contrast to conventional gain-of-function RhoA mutants such as RhoAG14V and RhoAQ63L which affect the GTP-hydrolysis activity, RhoAA161P and RhoAA161Vare both fast-cycling with drastically increased nucleotide dissociation and association rates, but only slightly reduced GTP-hydrolysis activity. We solved the crystal structures of GDP-bound RhoAA161P and RhoAA161V and saw that while RhoAA161P displays impaired solvent-mediated interactions to the bound nucleotide, RhoAA161V has a more exposed nucleotide binding pocket compared to RhoAWT and RhoAA161P. Interestingly, RhoAA161P and RhoAA161Vcan interact with effector targets in the GDP-bound states. Further 1H-15N HSQC NMR study provides evidence of the active population in GDP-bound RhoAA161V. Molecule dynamics (MD) simulations show that the dynamic properties of RhoA switch regions are affected differently by the two mutations. Thus, RhoAA161V and RhoAA161P are fast-cycling mutants with distinct mechanisms, and both likely endow their GDP-bound state towards an active conformation. These findings provide a better understanding of the oncogenic role of RhoA mutations in cancer and shine light on how changes in RhoA protein dynamic properties caused by mutations may affect its function. Citation Format: Yuan Lin, Theresa A. Ramelot, Simge Senyuz, Attila Gursoy, Hyunbum Jang, Ruth Nussinov, Ozlem Keskin, Yi Zheng. Tumor-associated RhoA mutants interact with effectors in both GDP- and GTP-bound states [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4388.

A practical and robust method to evaluate metabolic fluxes in primary pancreatic islets

ObjectiveEvaluation of mitochondrial oxygen consumption and ATP production is important to investigate pancreatic islet pathophysiology. Most studies use cell lines due to difficulties in measuring primary islet respiration, which requires specific equipment and consumables, is expensive and poorly reproducible. Our aim was to establish a practical method to assess primary islet metabolic fluxes using standard commercial consumables. MethodsPancreatic islets were isolated from mice/rats, dispersed with trypsin, and adhered to pre-coated standard Seahorse or Resipher microplates. Oxygen consumption was evaluated using a Seahorse Extracellular Flux Analyzer or a Resipher Real-time Cell Analyzer. ResultsWe provide a detailed protocol with all steps to optimize islet isolation with high yield and functionality. Our method requires a few islets per replicate; both rat and mouse islets present robust basal respiration and proper response to mitochondrial modulators and glucose. The technique was validated by other functional assays, which show these cells present conserved calcium influx and insulin secretion in response to glucose. We also show that our dispersed islets maintain robust basal respiration levels, in addition to maintaining up to 89% viability after five days in dispersed cultures. Furthermore, OCRs can be measured in Seahorse analyzers and in other plate respirometry systems, using standard materials. ConclusionsOverall, we established a practical and robust method to assess islet metabolic fluxes and oxidative phosphorylation, a valuable tool to uncover basic β-cell metabolic mechanisms as well as for translational investigations, such as pharmacological candidate discovery and islet transplantation protocols.

MORE FLORET1 controls anther development by negatively regulating key tapetal genes in both diploid and tetraploid rice.

Polyploid hybrid rice (Oryza sativa) has great potential for increasing yields. However, hybrid rice depends on male fertility and its regulation, which is less well studied in polyploid rice than in diploid rice. We previously identified a MYB transcription factor, MORE FLORET1 (MOF1), whose mutation causes male sterility in neo-tetraploid rice. MOF1 expression in anthers peaks at anther Stage 7 (S7) and progressively decreases to low levels at S10. However, it remains unclear how the dynamics of MOF1 expression contribute to male fertility. Here, we carefully examined anther development in both diploid and tetraploid mof1 rice mutants, as well as lines ectopically expressing MOF1 in a temporal manner. MOF1 mutations caused delayed degeneration of the tapetum and middle layer of anthers and aberrant pollen wall organization. Ectopic MOF1 expression at later stages of anther development led to retarded cytoplasmic reorganization of tapetal cells. In both cases, pollen grains were aborted and seed production was abolished, indicating that precise control of MOF1 expression is essential for male reproduction. We demonstrated that five key tapetal genes, CYP703A3 (CYTOCHROME P450 HYDROXYLASE 703A3), OsABCG26 (Oryza sativa ATP BINDING CASSETTE G26), PTC1 (PERSISTENT TAPETAL CELL1), PKS2 (POLYKETIDE SYNTHASE 2), and OsABCG15 (Oryza sativa ATP BINDING CASSETTE G15), exhibit expression patterns opposite to those of MOF1 and are negatively regulated by MOF1. Moreover, DNA affinity purification sequencing (DAP-seq), luciferase activity assays, and electrophoretic mobility shift assays indicated that MOF1 binds directly to the PKS2 promoter for transcriptional repression. Our results provide a mechanistic basis for the regulation of male reproduction by MOF1 in both diploid and tetraploid rice. This study will facilitate the development of polyploid male sterile lines, which are useful for breeding of polyploid hybrid rice.

Advancing bioenergetics-based modeling to improve climate change projections of marine ecosystems

Climate change has rapidly altered marine ecosystems and is expected to continue to push systems and species beyond historical baselines into novel conditions. Projecting responses of organisms and populations to these novel environmental conditions often requires extrapolations beyond observed conditions, challenging the predictive limits of statistical modeling capabilities. Bioenergetics modeling provides the mechanistic basis for projecting climate change effects on marine living resources in novel conditions, has a long history of development, and has been applied widely to fish and other taxa. We provide our perspective on 4 opportunities that will advance the ability of bioenergetics-based models to depict changes in the productivity and distribution of fishes and other marine organisms, leading to more robust projections of climate impacts. These are (1) improved depiction of bioenergetics processes to derive realistic individual-level response(s) to complex changes in environmental conditions, (2) innovations in scaling individual-level bioenergetics to project responses at the population and food web levels, (3) more realistic coupling between spatial dynamics and bioenergetics to better represent the local- to regional-scale differences in the effects of climate change on the spatial distributions of organisms, and (4) innovations in model validation to ensure that the next generation of bioenergetics-based models can be used with known and sufficient confidence. Our focus on specific opportunities will enable critical advancements in bioenergetics modeling and position the modeling community to make more accurate and robust projections of the effects of climate change on individuals, populations, food webs, and ecosystems.

Improved numerical solution of anisotropic poroelastic wave equation in microseismicity: Graphic process unit acceleration and moment tensor implementation

AbstractThe accuracy and computational efficiency of full waveform forward modelling in poroelastic media are crucial for microseismic monitoring. It enables intuitive, precise and efficient simulation of subsurface responses, thereby improving the reliability of moment tensor inversion and seismic source mechanism interpretation. Additionally, it reflects the role of fluid effects in waveform evolution. In this paper, based on the Biot mechanism, we derived the first‐order velocity–stress equation of poroelastic media and discretized the model using a rotated staggered grid. The rotated staggered grid can well adapt to anisotropic media with high contrast parameters. We provide the finite difference formula based on graphic process unit–acceleration and moment tensor and also provide the graphic process unit workflow for forward modelling of anisotropic poroelastic media. First, two models with different grid sizes were run based on single graphic process unit, 1‐thread Central Processing Unit (CPU) and 16‐thread CPU. The results show that the speedup factors are approximately 14.3 and 3.7, respectively, compared with the running time of 1‐thread CPU and 16‐thread CPU. Then, we compare and evaluate the response of three basic source mechanisms (isotropic expansion, double couple and compensated linear vector dipole) in the model. The comparison of analytical and numerical results verifies the effectiveness of the method. Furthermore, wavefield snapshots of two typical anisotropic media (vertical transversely isotropic and horizontal transversely isotropic) are analysed to correspond to different moment tensor sources. The results showed that the source mechanism does not change the isotropic and anisotropic plane and the wave travel time, but it does change the polarization amplitude of the velocity component. The attenuation of slow qP‐wave increases along with the increase of the value of viscosity. The effect of permeability on wavefield appears with the opposite effect of viscosity. Finally, the seismic waveform differences between multi‐layer elastic media and poroelastic media are compared and analysed. The results showed that the seismic wavefield and waveform of poroelastic media are more complex, the propagation speed of seismic waves is faster, but the attenuation of seismic waves is stronger.

Degradation of Water Pollutants by Biochar Combined with Advanced Oxidation: A Systematic Review

Recently, biochar has emerged as a promising option for environmentally friendly remediation due to its cost-effectiveness, extensive surface area, porosity, and exceptional electrical conductivity. Biochar-based advanced oxidation procedures (BC-AOPs) have gained popularity as an effective approach to breaking down organic pollutants in aqueous environments. It is commonly recognized that the main reactive locations within BC-AOPs consist of functional groups found on biochar, which encompass oxygen-containing groups (OCGs), imperfections, and persistent free radicals (PFRs). Additionally, the existence of metallic components supported on biochar and foreign atoms doped into it profoundly impacts the catalytic mechanism. These components not only modify the fundamental qualities of biochar but also serve as reactive sites. Consequently, this paper offers a comprehensive review of the raw materials, preparation techniques, modification approaches, and composite catalyst preparation within the biochar catalytic system. Special attention is given to explaining the modifications in biochar properties and their impacts on catalytic activity. This paper highlights degradation mechanisms, specifically pathways that include radical and non-radical processes. Additionally, it thoroughly examines the importance of active sites as catalysts and the basic catalytic mechanism of BC-AOPs. Finally, the potential and future directions of environmental remediation using biochar catalysts and advanced oxidation processes (AOPs) are discussed. Moreover, suggestions for future advancements in BC-AOPs are provided to facilitate further development.

The role of immune checkpoint inhibitors in the development and treatment of infectious processes

The incidence and prevalence of oncological diseases, which are in second place in terms of the frequency of causes of death, is steadily increasing among the population of the Russian Federation. Advances in translational medicine, including immunotherapy, have revolutionized cancer treatment strategies. A special breakthrough has been achieved in two areas of immunotherapy that have modernized cancer treatment: chimeric T-cell receptors and antibodies known as immune checkpoint inhibitors (ICTs) blocking cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein-1 (PD-1) and ligand programmed cell death receptor (PD-L1). ICTs enhance the adaptive immune response of the tumor and can cause adverse effects as a result of hyperactivation of T cells, which often leads to the emergence of an opportunistic infection. In addition, immunosuppressive drugs, which are often prescribed to mitigate the side effects associated with ICT, are also a risk factor for infection. The purpose of the review is to analyze the literature on possible relationships between ICT inhibitors and the risk of infection, as well as to consider the possible benefits of ICT inhibitors as a treatment for various types of infections, including viral, parasitic and fungal, as well as sepsis. Although ICT inhibitors have demonstrated the ability to significantly prolong the life expectancy of patients with advanced cancer, they often lead to adverse events, which often requires treatment with immunosuppressive drugs, including corticosteroids, anti-TNF and other biological agents. The overall effect of ICT inhibitors on human infections remains poorly understood. Further research is needed to understand the basic mechanisms of the immunological effects of ICT inhibitors on various types of infections, which in some cases may be beneficial.

Dry sliding wear behavior of sinter forged micrometric and nanometric yttrium oxide reinforced AA-7075 matrix composites

This study aims to investigate the dry sliding wear behaviour of AA-7075 based metal matrix composites developed by powder metallurgy route. AA-7075 metal matrix composites have been developed with 1–15 vol% micrometric yttrium oxide particulate reinforcement and 0.1–3 vol% nanometric yttrium oxide particulate reinforcement by sinter forging.The matrix and reinforcing powders were blended together to obtain a homogeneous composite powder mixture which was cold compacted and further sintered under pure nitrogen atmosphere. The sintered compacts were forged in a closed die to attain full density. The hot forged samples were further artificially age hardened to peak hardness. Wear behavior of AA-7075 and its composites at peak aged condition were investigated at various loads and sliding speeds. The coefficient of friction and wear rate were determined with respect to different volume fractions of micrometric and nanometric yttrium oxide additions to AA-7075 alloy matrix. The overall wear at a constant volume fraction was found to be lower for the compositions having nanometric Y2O3 as compared to micrometric Y2O3. Further the basic wear mechanism of pure aluminum 7075 alloy and reinforced composites consisted of adhesive wear with plastic deformation followed by abrasive wear (due to hard reinforcement particles).Material strengthening by precipitation hardening and reinforcement addition and the role of the forging operation and yttria reinforcements in the removal and uniform distribution of oxide layers present on the AA-7075 powder particles were accountable for the improvement in the wear resistance of the composites.

Targeting Sphingosine-1-Phosphate Signaling in Breast Cancer.

In recent years, newly emerging therapies, such as immune checkpoint inhibitors and antibody-drug conjugates, have further improved outcomes for breast cancer patients. However, recurrent and metastatic breast cancer often eventually develops resistance to these drugs, and cure is still rare. As such, the development of new therapies for refractory breast cancer that differ from conventional mechanisms of action is necessary. Sphingosine-1-phosphate (S1P) is a key molecule with a variety of bioactive activities, including involvement in cancer cell proliferation, invasion, and metastasis. S1P also contributes to the formation of the cancer microenvironment by inducing surrounding vascular- and lymph-angiogenesis and regulating the immune system. In this article, we outline the basic mechanism of action of S1P, summarize previous findings on the function of S1P in cancer cells and the cancer microenvironment, and discuss the clinical significance of S1P in breast cancer and the therapeutic potential of targeting S1P signaling.

Physiological and transcriptome analysis of acclimatory response to cold stress in marine red alga Pyropia yezoensis

Red macroalga Pyropia yezoensis is a high valuable cultivated marine crop. Its acclimation to cold stress is especially important for long cultivation period across winter in coasts of warm temperate zone in East Asia. In this study, the response of P. yezoensis thalli to low temperature was analyzed on physiology and transcriptome level, to explore its acclimation mechanism to cold stress. The results showed that the practical photosynthesis activity (indicated by ΦPSII and qP) was depressed and pigment allophycocyanin content was decreased during the cold stress of 48 h. However, the Fv/Fm and non-photochemical quenching increased significantly after 24 h, and the average growth rate of thalli also rebounded from 24 to 48 h, indicating a certain extent of acclimation to cold stress. On transcriptionally, the low temperature promoted the expression of differentially expressed genes (DEGs) related to carbohydrate metabolism and energy metabolism, while genes related to photosynthetic system were depressed. The increased expression of DEGs involved in ribosomal biogenesis and lipid metabolism which could accelerate protein synthesis and enhance the degree of fatty acid unsaturation, might help P. yezoensis thallus cells to cope with cold stress. Further co-expression network analysis revealed differential expression trends along with stress time, and corresponding hub genes play important roles in the systemic acquired acclimation to cold stress. This study provides basic mechanisms of P. yezoensis acclimation to cold temperature and may aid in exploration of functional genes for genetic breeding of economic macroalgae.

Recent Developments in Graphitic Carbon Nitride and Its Interfaces for Effective Water Splitting

Electrocatalytic and photocatalytic water splitting are effective pathways for energy conversion to overcome from the reliance on the depletion fossil fuels and preclude the severe degradation of global climate. The review begins with the basic principle and mechanisms involved in both electro/photocatalysis of water splitting. Graphitic carbon nitride (g‐C3N4) is an interesting catalyst for water splitting due to its layered conjugated metal free semiconductor, owing to its unique physicochemical characteristics. However to improve some of the features of g‐C3N4 including long term stability, large active sites, electronic band structure, low recombination rate of photogenerated charges, and many more, interface engineering with different materials have been introduced to improve the catalytic activity. The review emphasizes the basics of g‐C3N4 with its interesting properties such as chemical and thermal stability, large surface area, unique optoelectronic properties, exfoliated layered structure, and tunable surface functional groups. The various strategies that have been used to modulate catalytic activity of this material are discussed, including morphology modulation, elemental doping, interface engineering with metals, and semiconductors. Towards end of the review, a summary and future perspective is presented.

New aspects of femtosecond laser ablation of Si in water: a material perspective

We report a study of the role of material’s conductivity in determining the morphology of nanoparticles and nanostructures produced by ultrafast laser ablation of solids. Nanoparticles and textured surfaces formed by laser ablation display a wide variation in size and morphology depending on the material. In general, these qualities can be grouped as to material type, insulator, semiconductor, or metal; although each has many other different material properties that make it difficult to identify the critical material factor. In this report, we study these nanoparticle/surface structural characteristics as a function of silicon (Si) resistivity, thus honing-in on this critical parameter and its effects. The results show variations in morphology, optical, and nonlinear properties of Si nanoparticles. The yield of colloidal Si nanoparticles increased with an increase in the conductivity of Si. Laser-induced periodic surface structures formed on ablated substrates are also found to be sensitive to the initial conductivity of the material. Further, the laser ablation of Gamma-irradiated Si has been investigated to verify the influence of altered conductivity on the formation of Si nanoparticles. These observations are interpreted using the basic mechanisms of the laser ablation process in a liquid and its intricate relation with the initial density of states and thermal conductivities of the target material.

Electrostatic potentials of atomic nanostructures at metal surfaces quantified by scanning quantum dot microscopy

The discrete and charge-separated nature of matter — electrons and nuclei — results in local electrostatic fields that are ubiquitous in nanoscale structures and relevant in catalysis, nanoelectronics and quantum nanoscience. Surface-averaging techniques provide only limited experimental access to these potentials, which are determined by the shape, material, and environment of the nanostructure. Here, we image the potential over adatoms, chains, and clusters of Ag and Au atoms assembled on Ag(111) and quantify their surface dipole moments. By focusing on the total charge density, these data establish a benchmark for theory. Our density functional theory calculations show a very good agreement with experiment and allow a deeper analysis of the dipole formation mechanisms, their dependence on fundamental atomic properties and on the shape of the nanostructures. We formulate an intuitive picture of the basic mechanisms behind dipole formation, allowing better design choices for future nanoscale systems such as single-atom catalysts.

Prolactin effects on the pathogenesis of diabetes mellitus.

Prolactin (PRL) is a pituitary hormone promoting lactation in response to the suckling reflex. Beyond its well-known effects, novel tissue-specific and metabolic functions of PRL are emerging. To dissect PRL as a critical mediator of whole-body gluco-insulinemic sensitivity. PubMed-based search with the following terms 'prolactin', 'glucose metabolism', 'type 2 diabetes mellitus', 'type 1 diabetes mellitus', 'gestational diabetes mellitus' was performed. The identification of the PRL-glucose metabolism network poses the basis for unprecedented avenues of research in the pathogenesis of diabetes mellitus type 1 or 2, as well as of gestational diabetes. In this regard, it is of timely relevance to define properly the homeostatic PRL serum levels since glucose metabolism could be influenced by the circulating amount of the hormone. This review underscores the basic mechanisms of regulation of pancreatic β-cell functions by PRL and provides a revision of articles which have investigated the connection between PRL unbalancing and diabetes mellitus. Future studies are needed to elucidate the burden and the role of PRL in the regulation of glucose metabolism and determine the specific PRL threshold that may impact the management of diabetes. A careful evaluation and context-driven interpretation of PRL levels (e.g., pregnancy, PRL-secreting pituitary adenomas, drug-related hyper- and hypoprolactinemia) could be critical for the correct screening and management of glucometabolic disorders, such as type 1 or 2 as well as gestational diabetes mellitus.