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1.
Risk Anal ; 2024 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-39261276

RESUMEN

Critical infrastructure systems (CISs) are the cornerstone of modern cities. Substantial economic losses and social impacts are caused once natural disasters or man-made disruptions attack the CISs. As a "resilient city" has become an essential theme of communities' sustainable development, research on resilience and its practice in industries boost the CISs' capacity to respond and adapt to changing environments. From the Web of Science (WOS) Core Collection, this study screened 1,247 scientific articles related to resilience in CISs and conducted a bibliometric analysis to investigate the evolution and future potential in this field. Topic visualized networks were constructed for CIS resilience using CiteSpace, a dedicated tool for visualizing and analyzing trends and patterns in scientific literature. The results demonstrate collaborative research networks among countries, institutions, main scholar/group networks, and leading journals publishing CIS resilience work. This study also explained how the research interest evolved over the last 20 years and found the current frontiers pointing to "power systems resilience" and "supply chain resilience." The reasons were discussed subsequently from the perspectives of the influence that natural hazards (based on the EM-DAT data) and government policies have upon CISs' resilience work.

2.
World J Clin Cases ; 12(25): 5673-5680, 2024 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-39247737

RESUMEN

BACKGROUND: Due to frequent and high-risk sports activities, the elbow joint is susceptible to injury, especially to cartilage tissue, which can cause pain, limited movement and even loss of joint function. AIM: To evaluate magnetic resonance imaging (MRI) multisequence imaging for improving the diagnostic accuracy of adult elbow cartilage injury. METHODS: A total of 60 patients diagnosed with elbow cartilage injury in our hospital from January 2020 to December 2021 were enrolled in this retrospective study. We analyzed the accuracy of conventional MRI sequences (T1-weighted imaging, T2-weighted imaging, proton density weighted imaging, and T2 star weighted image) and Three-Dimensional Coronary Imaging by Spiral Scanning (3D-CISS) in the diagnosis of elbow cartilage injury. Arthroscopy was used as the gold standard to evaluate the diagnostic effect of single and combination sequences in different injury degrees and the consistency with arthroscopy. RESULTS: The diagnostic accuracy of 3D-CISS sequence was 89.34% ± 4.98%, the sensitivity was 90%, and the specificity was 88.33%, which showed the best performance among all sequences (P < 0.05). The combined application of the whole sequence had the highest accuracy in all sequence combinations, the accuracy of mild injury was 91.30%, the accuracy of moderate injury was 96.15%, and the accuracy of severe injury was 93.33% (P < 0.05). Compared with arthroscopy, the combination of all MRI sequences had the highest consistency of 91.67%, and the kappa value reached 0.890 (P < 0.001). CONCLUSION: Combination of 3D-CISS and each sequence had significant advantages in improving MRI diagnostic accuracy of elbow cartilage injuries in adults. Multisequence MRI is recommended to ensure the best diagnosis and treatment.

3.
Adv Mater ; : e2403807, 2024 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-39139010

RESUMEN

The chirality-induced spin selectivity (CISS) effect is a fascinating phenomenon that correlates the molecular structure with electron spin-polarization (SP). Experimental procedures to quantify the spin-filtering magnitude have extensively used magnetic-field-dependent conductive AFM. In this work chiral crystals of imide-substituted coronene bisimide ((S)-CBI-GCH) are studied to explain the dynamics of the current-voltage I - V spectra and the origin of superimposed peaks are investigated. A dynamic voltage-sweep rate-dependent phenomenon can give rise to complex I - V curves. The redox group, capable of localization of charge, acts as a localized state that interferes with the continuum of the π - π stacking, giving rise to Fano resonances. A novel mechanism for dynamic transport is introduced, which provides insight into the origin of spin-polarized charge in crystallized CBI-GCH molecules after absorption on a metallic substrate, guided by transient charge polarization. Crucially, interference between charge localization and delocalization during transport may be important properties in understanding the magnetochiral phenomena observed by electrostatic force microscopy. Finally, it is observed that charge trapping sensitively modifies the injection barrier from direct tunneling to Fowler-Nordheim tunneling transport supporting nonlinearity in CISS for this class of molecules.

4.
Front Public Health ; 12: 1399025, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39157533

RESUMEN

Introduction: The death of a patient negatively affects the professional dimension of nurses' functioning and also their private lives, where professional experiences and emotions are often transmitted. Aim of the study: The main aim of the study was to discover how the nursing staff assessed their self-efficacy in dealing with the death of a patient. Materials and methods: The researchers used a diagnostic survey method and a self-authored survey, Life Satisfaction Scale (SWLS), Coping Inventory for Stressful Situations (CISS), Generalized Self-Efficacy Scale (GSES), Courtauld Emotional Control Scale (CECS), The Death Anxiety and Fascination Scale with the Death Anxiety Subscale. The study group consisted of 287 individuals. Results: Working in a hospital is stressful in the opinion of 79.44% of the respondents. 39.37% of the respondents feared death. In the course of work, the death of a patient in the department was sometimes experienced by 34.84% of the respondents, always experienced by 29.97%. The respondents usually did not make their compassion for a dying patient based on the patient's position in society (57.84%). In the case of the majority (84.67%) of the respondents, the employer did not provide mental support for the staff in difficult situations. The majority of the respondents did not feel the need to broaden their knowledge of death and dying (64.11%). Conclusion: The surveyed nurses most often presented low or average life satisfaction, high self-efficacy, average levels of stress and coping in all three styles (with a preference for avoidance-oriented), and a high level of death fascination and an average level of death anxiety. The majority of the nurses in difficult situations and when a stressful situation occurred did not receive support from their employer or from physicians, but could count on the assistance of fellow nurses and a divisional nurse. The majority of the respondents felt that psychological support in their work was important and would gladly benefit from it. Although most nurses did not feel the need to broaden their knowledge of death/dying, they would take part in such a course if it were possible.


Asunto(s)
Adaptación Psicológica , Actitud Frente a la Muerte , Autoeficacia , Humanos , Femenino , Masculino , Adulto , Encuestas y Cuestionarios , Persona de Mediana Edad , Personal de Enfermería en Hospital/psicología , Enfermeras y Enfermeros/psicología
5.
J Clin Med ; 13(16)2024 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-39200835

RESUMEN

Background: In the contemporary world, a cult of perfection is being created, and deviations from such an ideal image are becoming socially unacceptable. A particular situation arises when a defect or symptoms of a disease appear on the skin, which, in the case of people suffering from psoriasis, are a source of stress, dissatisfaction with the disease, and a reduction in quality of life. The aim of this study was to assess whether the quality of life related to the occurrence of psoriasis and the level of acceptance of the disease affect coping strategies in stressful situations. Methods: The study involved 111 people with common psoriasis (46.8% women and 53.2% men). Inclusion criteria were as follows: a diagnosis of common psoriasis for at least 0.5 years, no other types of psoriasis, no mental illnesses, and an informed consent of the respondent to participate in the study. In order to compile the research input, a proprietary questionnaire was used along with the following standardised tools: the Dermatology Life Quality Index (DLQI), the Acceptance of Illness Scale (AIS), and the Coping Inventory for Stressful Situations (CISS). Results: The duration of the disease in the studied population varied and ranged from 0.5 years to over 50 years. Most respondents showed relatively low DLQI scores, with an average value of 10.8 points. In stressful situations (CISS), the respondents primarily used a strategy based on rational thinking (Task-oriented coping), with approximately 54 points on average; followed by an avoidant style (Avoidance-oriented coping), with approximately 50 points on average; and least often an emotional style (Emotion-oriented coping), with approximately 46 points on average. The average level of disease acceptance (AIS) in the studied group equalled approximately 26 points. Conclusions: Psoriatic lesions on the torso caused less rational behaviour in stressful situations (a decrease in the Task-oriented coping) in women but had the opposite result in men, whereas psoriatic lesions on the head stimulated the use of Task-oriented coping in women but had the opposite result in men. The higher the acceptance of the disease (AIS) presented by the respondents, the less often they used an emotional strategy (Emotion-oriented coping) in stressful situations. The higher the quality of life (DLQI) was, the lower the values of Emotion-oriented coping were noted.

6.
Sensors (Basel) ; 24(16)2024 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-39205107

RESUMEN

We present robust pixel design methodologies for a vertical avalanche photodiode-based CMOS image sensor, taking account of three critical practical factors: (i) "guard-ring-free" pixel isolation layout, (ii) device characteristics "insensitive" to applied voltage and temperature, and (iii) stable operation subject to intense light exposure. The "guard-ring-free" pixel design is established by resolving the tradeoff relationship between electric field concentration and pixel isolation. The effectiveness of the optimization strategy is validated both by simulation and experiment. To realize insensitivity to voltage and temperature variations, a global feedback resistor is shown to effectively suppress variations in device characteristics such as photon detection efficiency and dark count rate. An in-pixel overflow transistor is also introduced to enhance the resistance to strong illumination. The robustness of the fabricated VAPD-CIS is verified by characterization of 122 different chips and through a high-temperature and intense-light-illumination operation test with 5 chips, conducted at 125 °C for 1000 h subject to 940 nm light exposure equivalent to 10 kLux.

7.
Cureus ; 16(5): e61393, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38947685

RESUMEN

Background The cerebellopontine angle (CPA) cistern houses vital neurovascular structures such as cranial nerves V, VII, and VIII and the anterior inferior cerebellar artery (AICA), often leading to neurovascular compression syndromes due to its complex anatomy. Although vascular compression is a recognized cause of certain neuralgias, its association with otologic symptoms such as tinnitus, hearing loss, and dizziness remains uncertain. Hence, this study aims to determine the prevalence of the AICA vascular loop in the CPA cistern on MRI in patients with asymptomatic audiovestibular symptoms. Methodology Adult patients who underwent MRI, including the posterior fossa's high-resolution volumetric T2 sequence (three-dimensional constructive interference in steady state (3D-CISS)), were assessed. Patients with a history of audiovestibular symptoms (tinnitus/dizziness/vertigo/sensorineural hearing loss), intracranial tumor, vascular lesions, intracranial surgery, brain radiation therapy, traumatic brain injury, poor image quality, and MRI scans without 3D-CISS sequences were excluded. Two radiologists independently reviewed 114 (228 sides) MRI studies for the vascular loop of AICA in the CPA cistern and the extension of the AICA loop into the ipsilateral internal acoustic meatus which was graded by Chavda's classification. Results The prevalence of vascular loop of AICA in the CPA cistern was as high as 47.6% in asymptomatic patients. Grade I Chavda vascular loop was the most common type followed by type II, with type III being the least common type. Conclusions Knowledge regarding the high prevalence of the AICA loop in the asymptomatic population and the lack of significant correlation between the presence of the AICA loop and otovestibular symptoms should be considered in preoperative planning for decompression procedures.

8.
Chirality ; 36(8): e23706, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39077832

RESUMEN

Helicenes represent an important class of chiral organic material with promising optoelectronic properties. Hence, functionalization of surfaces with helicenes is a key step towards new organic material devices. This review presents different aspects of adsorption and modification of metal surfaces with different helicene species. Topics addressed are chiral crystallization, that is, 2D conglomerate versus racemate crystallization, breaking of mirror-symmetry in racemates, chirality-induced spin selectivity, and stereoselective on-surface chemistry.

9.
Cureus ; 16(5): e60071, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38860061

RESUMEN

Trigeminal neuralgia (TN) poses diagnostic challenges due to its complex origins, often associated with neurovascular compression. Advanced imaging techniques, particularly magnetic resonance imaging (MRI) with the fast imaging employing steady-state acquisition (FIESTA) sequence, offer crucial insights into TN pathophysiology. This prospective cross-sectional observational study aimed to elucidate MRI's utility in diagnosing TN and correlating imaging findings with clinical manifestations and treatment outcomes. A cohort of 41 patients clinically suspected of TN underwent MRI evaluation at Acharya Vinoba Bhave Rural Hospital, Sawangi (Meghe), Wardha, utilizing various sequences including FIESTA. Analysis revealed a higher incidence among females, predominant unilateral presentation, and a higher prevalence of abnormal MRI findings, with neurovascular compression as the leading etiology. Correlation analysis demonstrated significant associations between facial pain localized to the trigeminal nerve distribution, triggering factors, and abnormal MRI findings. Gender distribution did not significantly influence MRI findings. Treatment outcomes favored microvascular surgery over conservative management in cases of neurovascular compression. This study underscores MRI's pivotal role, particularly FIESTA, in TN evaluation, guiding personalized treatment strategies and emphasizing the importance of integrated clinical and imaging approaches. Further research is warranted to validate these findings and explore additional imaging modalities for a deeper understanding of TN pathogenesis.

10.
Anal Bioanal Chem ; 416(16): 3677-3685, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38755462

RESUMEN

Chirality is a fundamental and ubiquitous property of nature involved in multiple fields of science. In particular, the possible resolution of the enantiomeric forms of a molecule is crucial in the pharmaceutical, food, and agrochemical industries. The search for efficient, broad-spectrum, and yet simple methods for obtaining enantiomerically pure substances is a current challenge. Enantioselective resolution methods rely on an asymmetric environment that allows the two antipodes of a chiral molecule to be distinguished. In addition to enantiomeric separation techniques, such as chromatography and electrophoresis, new promising approaches involving out-of-the-scheme synergistic effects between chiral selectors (CS) and external stimuli are emerging. This Trends article discusses different enantioselective mechanisms triggered by unconventional physicochemical stimuli for the design of avant-garde approaches that could offer novel perspectives in the field of chiral resolution.

11.
Nano Lett ; 24(21): 6210-6217, 2024 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-38709107

RESUMEN

The spin-orbit coupling (SOC), the dynamics of the nonequilibrium transport process, and the breaking of time-reversal and space-inversion symmetries have been regarded as key factors for the emergence of chirality-induced spin selectivity (CISS) and chirality-dependent spin currents in helix molecules. In this work, we demonstrated the generation of persistent CISS currents in various circular single-stranded DNAs and 310-helix proteins for the first time, regardless of whether an external magnetic flux is applied or not. This new CISS effect presents only in equilibrium transport processes, distinct from the traditional CISS observed in nonequilibrium transport processes and linear helix molecules; we term it as the PCISS effect. Notably, PCISS manifests irrespective of whether the SOC is chirality-driven or stems from heavy-metal substrates, making it an efficient way to generate chirality-locked pure spin currents. Our research establishes a novel paradigm for examining the underlying physics of the CISS effect.

12.
Adv Mater ; 36(29): e2313708, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38766930

RESUMEN

Chiral oligopeptide monolayers are adsorbed on a ferromagnetic surface and their magnetoresistance is measured as a function of the angle between the magnetization of the ferromagnet and the surface normal. These measurements are conducted as a function of temperature for both enantiomers. The angle dependence is found to follow a changing trend with a period of 360°. Quantum simulations reveal that the angular distribution can be obtained only if the monolayer has significant effective spin orbit coupling (SOC), that includes contribution from the vibrations. The model shows that SOC only in the leads cannot reproduce the observed angular dependence. The simulation can reproduce the experiments if it included electron-phonon interactions and dissipation.

13.
Brain Spine ; 4: 102724, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38510606

RESUMEN

Introduction: Intradural lumbar disc herniations (IDDH) are unusual and represent less than 0.3% of all lumbar disc herniations. They have a higher incidence of cauda equina syndrome. The possibility of intradural disc herniation is often missed on Magnetic Resonance Imaging (MRI) and during surgery if the size of the disc prolapse is inconsistent with the compression seen on the MRI. In such situations, the possibility of IDDH should be suspected. Research question: How to diagnose intradural disc herniation pre-operatively? Surgical techniques if the intra-dural disc herniation is encountered intra-operatively. Material and methods: In this article, we describe a case report of an intradural disc herniation (IDDH) causing cauda equina syndrome at the L4-5 level and who underwent surgical decompression. This case report highlights that by doing a dorsal durotomy and by using microsurgical techniques, excision of the intradural disc fragment can be achieved without any rootlet injury. Results: At a 2-year follow-up, the patient has recovered completely from motor weakness and bowel and bladder incontinence. Discussion and conclusion: Though uncommon intra-dural disc herniation can be diagnosed pre-operatively by its characteristic signs or by using newer techniques like 3-dimensional constructive interference in steady state (CISS) MRI. Intra-operative ultrasonography (IOUS) is a handy tool to localise and diagnose intra-dural disc herniation intra-operatively and its use is encouraged. Timely intervention can lead to acceptable outcomes even with cauda equina syndrome.

14.
ACS Nano ; 18(12): 8663-8672, 2024 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-38484339

RESUMEN

One of the central aims of the field of spintronics is the control of individual electron spins to effectively manage the transmission of quantized data. One well-known mechanism for controlling electronic spin transport is the chiral-induced spin-selectivity (CISS) effect in which a helical nanostructure imparts a preferential spin orientation on the electronic transport. One potential application of the CISS effect is as a transduction pathway between electronic spin and circularly polarized light within nonreciprocal photonic devices. In this work, we identify and quantify the degree of chiral-induced spin-selective electronic transport in helical polyaniline films using magnetoconductive atomic force microscopy (mcAFM). We then induce circularly polarized quantum light emission from CdSe/CdS core/shell quantum dots placed on these films, demonstrating a degree of circular polarization of up to ∼21%. Utilizing time-resolved photoluminescence microscopy, we measure the radiative lifetime difference associated with left- and right-handed circular polarizations of single emitters. These lifetime differences, in combination with Kelvin probe mapping of the variation of surface potential with magnetization of the substrate, help establish an energy level diagram describing the spin-dependent transport pathways that enable the circularly polarized photoluminescence.

15.
Tomography ; 10(2): 203-214, 2024 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-38393284

RESUMEN

BACKGROUND: Constructive interference in steady state (CISS) is a gradient echo magnetic resonance imaging (MRI) pulse sequence that provides excellent contrast between cerebrospinal fluid and adjacent structures but is prone to banding artifacts due to magnetic field inhomogeneities. We aimed to characterize artifacts in the inner ear and eye. METHODS: In 30 patients (60 ears/eyes) undergoing CISS sequence MRI, nine low-signal intensity regions were identified in the inner ear and compared to temporal bone histopathology. The number and angle of bands across the eye were examined. RESULTS: In the cochlea, all ears had regions of low signal corresponding to anatomy (modiolus (all), spiral lamina (n = 59, 98.3%), and interscalar septa (n = 50, 83.3%)). In the labyrinth, the lateral semicircular canal crista (n = 42, 70%) and utricular macula (n = 47, 78.3%) were seen. Areas of low signal in the vestibule seen in all ears may represent the walls of the membranous utricle. Zero to three banding artifacts were seen in both eyes (right: 96.7%, mean 1.5; left: 93.3%, mean 1.3). CONCLUSION: Low signal regions in the inner ear on CISS sequences are common and have consistent patterns; most in the inner ear represent anatomy, appearing blurred due to partial volume averaging. Banding artifacts in the eye are more variable.


Asunto(s)
Oído Interno , Humanos , Oído Interno/anatomía & histología , Oído Interno/patología , Cóclea/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos
16.
Front Neurol ; 15: 1340085, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38327626

RESUMEN

Background and purpose: Perforator artery disease (PAD) is an important subtype of ischemic stroke. The risk factors affecting the prognosis of patients with PAD are unclear. This study aimed to investigate the risk factors affecting the unfavorable prognosis of PAD. Methods: Patients with PAD were enrolled from Dushu Lake Hospital Affiliated to Soochow University and diagnosed as stroke with PAD during the period from September 2021 to July 2023 and followed up with a modified Rankin Scale (mRS) after 90 days, defining the mRS of 0-2 as a group with favorable prognosis, and 3-6 as a group with unfavorable functional outcome. Logistic regression was used to identify predictors for PAD. Multiple logistic regression analysis and receiver operating characteristics (ROC) were used to identify predictors of unfavorable prognosis. Results: Of the 181 enrolled patients, 48 (26.5%) were identified with unfavorable prognosis. On multivariate analysis, increased age (OR = 1.076, 95% CI: 1.012 ~ 1.144, p = 0.019), higher National Institutes of Health Stroke Scale (NIHSS) score at admission (OR = 2.930, 95% CI: 1. 905 ~ 4.508, p < 0.001), and increased neutrophil-to-lymphocyte ratio (NLR) (OR = 3.028, 95% CI: 1.615 ~ 5.675, p = 0.001) were independent risk factors for unfavorable prognosis in patients with PAD, and the area under the receiver operating characteristic curve was 0.590, 0.905, and 0.798, and the multi-factor diagnostic model (Model 2) showed reliable diagnostic specificity and sensitivity (area under the curve = 0.956, p < 0.001, specificity 0.805, sensitivity 0.958, accuracy 0.845). Conclusion: Increased baseline NLR and NIHSS score and aging may be independent risk factors for unfavorable prognosis of patients with PAD. NLR can be used as a potential biological indicator to predict the prognosis of stroke with PAD.

17.
Chemphyschem ; 25(10): e202400033, 2024 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-38411033

RESUMEN

The reaction of D-glucose oxidase (GOx) with D- and L-glucose was investigated using confocal fluorescence microscopy and Hall voltage measurements, after the enzyme was adsorbed as a monolayer. By adsorbing the enzyme on a ferromagnetic substrate, we verified that the reaction is spin dependent. This conclusion was supported by monitoring the reaction when the enzyme is adsorbed on a Hall device that does not contain any magnetic elements. The spin dependence is consistent with the chiral-induced spin selectivity (CISS) effect; it can be explained by the improved fidelity of the electron transfer process through the chiral enzyme due to the coupling of the linear momentum of the electrons and their spin. Since the reaction studied often serve as a model system for enzymatic activity, the results may suggest the general importance of the spin-dependent electron transfer in bio-chemical processes.


Asunto(s)
Glucosa Oxidasa , Glucosa , Glucosa Oxidasa/química , Glucosa Oxidasa/metabolismo , Glucosa/química , Glucosa/metabolismo , Transporte de Electrón , Biocatálisis , Adsorción
18.
Angew Chem Int Ed Engl ; 63(4): e202315146, 2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-37953459

RESUMEN

The chiral-induced spin selectivity effect (CISS) is a breakthrough phenomenon that has revolutionized the field of electrocatalysis. We report the first study on the electron spin-dependent electrocatalysis for the oxygen reduction reaction, ORR, using iron phthalocyanine, FePc, a well-known molecular catalyst for this reaction. The FePc complex belongs to the non-precious catalysts group, whose active site, FeN4, emulates catalytic centers of biocatalysts such as Cytochrome c. This study presents an experimental platform involving FePc self-assembled to a gold electrode surface using chiral peptides (L and D enantiomers), i.e., chiro-self-assembled FePc systems (CSAFePc). The chiral peptides behave as spin filters axial ligands of the FePc. One of the main findings is that the peptides' handedness and length in CSAFePc can optimize the kinetics and thermodynamic factors governing ORR. Moreover, the D-enantiomer promotes the highest electrocatalytic activity of FePc for ORR, shifting the onset potential up to 1.01 V vs. RHE in an alkaline medium, a potential close to the reversible potential of the O2 /H2 O couple. Therefore, this work has exciting implications for developing highly efficient and bioinspired catalysts, considering that, in biological organisms, biocatalysts that promote O2 reduction to water comprise L-enantiomers.

19.
Adv Mater ; 36(14): e2308666, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38153192

RESUMEN

From the beginning of molecular theory, the interplay of chirality and magnetism has intrigued scientists. There is still the question if enantiospecific adsorption of chiral molecules occurs on magnetic surfaces. Enantiomer discrimination was conjectured to arise from chirality-induced spin separation within the molecules and exchange interaction with the substrate's magnetization. Here, it is shown that single helical aromatic hydrocarbons undergo enantioselective adsorption on ferromagnetic cobalt surfaces. Spin and chirality sensitive scanning tunneling microscopy reveals that molecules of opposite handedness prefer adsorption onto cobalt islands with opposite out-of-plane magnetization. As mobility ceases in the final chemisorbed state, it is concluded that enantioselection must occur in a physisorbed transient precursor state. State-of-the-art spin-resolved ab initio simulations support this scenario by refuting enantio-dependent chemisorption energies. These findings demonstrate that van der Waals interaction should also include spin-fluctuations which are crucial for molecular magnetochiral processes.

20.
Small ; : e2308233, 2023 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-38050945

RESUMEN

The interplay between chirality and magnetism is a source of fascination among scientists for over a century. In recent years, chirality-induced spin selectivity (CISS) has attracted renewed interest. It is observed that electron transport through layers of homochiral molecules leads to a significant spin polarization of several tens of percent. Despite the abundant experimental evidence gathered through mesoscopic transport measurements, the exact mechanism behind CISS remains elusive. This study reports spin-selective electron transport through single helical aromatic hydrocarbons that are sublimed in vacuo onto ferromagnetic cobalt surfaces and examined with spin-polarized scanning tunneling microscopy (SP-STM) at a temperature of 5 K. Direct comparison of two enantiomers under otherwise identical conditions revealed magnetochiral conductance asymmetries of up to 50% when either the molecular handedness is exchanged or the magnetization direction of the STM tip or Co substrate is reversed. Importantly, the results rule out electron-phonon coupling and ensemble effects as primary mechanisms responsible for CISS.

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