Key role of chemistry versus bias in electrocatalytic oxygen evolution.

The oxygen evolution reaction has an important role in many alternative-energy schemes because it supplies the protons and electrons required for converting renewable electricity into chemical fuels1-3. Electrocatalysts accelerate the reaction by facilitating the required electron transfer4, as well as the formation and rupture of chemical bonds5. This involvement in fundamentally different processes results in complex electrochemical kinetics that can be challenging to understand and control, and that typically depends exponentially on overpotential1,2,6,7. Such behaviour emerges when the applied bias drives the reaction in line with the phenomenological Butler-Volmer theory, which focuses on electron transfer8, enabling the use of Tafel analysis to gain mechanistic insight under quasi-equilibrium9-11 or steady-state assumptions12. However, the charging of catalyst surfaces under bias also affects bond formation and rupture13-15, the effect of which on the electrocatalytic rate is not accounted for by the phenomenological Tafel analysis8 and is often unknown. Here we report pulse voltammetry and operando X-ray absorption spectroscopy measurements on iridium oxide to show that the applied bias does not act directly on the reaction coordinate, but affects the electrocatalytically generated current through charge accumulation in the catalyst. We find that the activation free energy decreases linearly with the amount of oxidative charge stored, and show that this relationship underlies electrocatalytic performance and can be evaluated using measurement and computation. We anticipate that these findings and our methodology will help to better understand other electrocatalytic materials and design systems with improved performance.

Unveiling Highly Sensitive Active Site in Atomically Dispersed Gold Catalysts for Enhanced Ethanol Dehydrogenation.

Developing a desirable ethanol dehydrogenation process necessitates a highly efficient and selective catalyst with low cost. Herein, we show that the "complex active site" consisting of atomically dispersed Au atoms with the neighboring oxygen vacancies (Vo) and undercoordinated cation on oxide supports can be prepared and display unique catalytic properties for ethanol dehydrogenation. The "complex active site" Au-Vo-Zr3+ on Au1/ZrO2 exhibits the highest H2 production rate, with above 37,964 mol H2 per mol Au per hour (385 g H2 g Au - 1 ${{\rm{g}}_{{\rm{Au}}}^{ - 1} }$ h-1) at 350 °C, which is 3.32, 2.94 and 15.0 times higher than Au1/CeO2, Au1/TiO2, and Au1/Al2O3, respectively. Combining experimental and theoretical studies, we demonstrate the structural sensitivity of these complex sites by assessing their selectivity and activity in ethanol dehydrogenation. Our study sheds new light on the design and development of cost-effective and highly efficient catalysts for ethanol dehydrogenation. Fundamentally, atomic-level catalyst design by colocalizing catalytically active metal atoms forming a structure-sensitive "complex site", is a crucial way to advance from heterogeneous catalysis to molecular catalysis. Our study advanced the understanding of the structure sensitivity of the active site in atomically dispersed catalysts.

The rise of electrochemical NAPXPS operated in the soft X-ray regime exemplified by the oxygen evolution reaction on IrOx electrocatalysts.

Photoelectron spectroscopy offers detailed information about the electronic structure and chemical composition of surfaces, owing to the short distance that the photoelectrons can escape from a dense medium. Unfortunately, photoelectron based spectroscopies are not directly compatible with the liquids required to investigate electrochemical processes, especially in the soft X-ray regime. To overcome this issue, different approaches based on photoelectron spectroscopy have been developed in our group over the last few years. The performance and the degree of information provided by these approaches are compared with those of the well established bulk sensitive spectroscopic approach of total fluorescence yield detection, where the surface information gained from this approach is enhanced using samples with large surface to bulk ratios. The operation of these approaches is exemplified and compared using the oxygen evolution reaction on IrOx catalysts. We found that all the approaches, if properly applied, provide similar information about surface oxygen speciation. However, using resonant photoemission spectroscopy, we were able to prove that speciation is more involved and complex than previously thought during the oxygen evolution reaction on IrOx based electrocatalysts. We found that the electrified solid-liquid interface is composed of different oxygen species, where the terminal oxygen atoms on iridium are the active species, yielding the formation of peroxo species and, finally, dioxygen as the reaction product. Thus, the oxygen-oxygen bond formation is dominated by peroxo species formation along the reaction pathway. Furthermore, the methodologies discussed here open up opportunities to investigate electrified solid-liquid interfaces in a multitude of electrochemical processes with unprecedented speciation capabilities, which are not accessible by one-dimensional X-ray spectroscopies.

Surface Electron-Hole Rich Species Active in the Electrocatalytic Water Oxidation.

Iridium and ruthenium and their oxides/hydroxides are the best candidates for the oxygen evolution reaction under harsh acidic conditions owing to the low overpotentials observed for Ru- and Ir-based anodes and the high corrosion resistance of Ir-oxides. Herein, by means of cutting edge operando surface and bulk sensitive X-ray spectroscopy techniques, specifically designed electrode nanofabrication and ab initio DFT calculations, we were able to reveal the electronic structure of the active IrOx centers (i.e., oxidation state) during electrocatalytic oxidation of water in the surface and bulk of high-performance Ir-based catalysts. We found the oxygen evolution reaction is controlled by the formation of empty Ir 5d states in the surface ascribed to the formation of formally IrV species leading to the appearance of electron-deficient oxygen species bound to single iridium atoms (µ1-O and µ1-OH) that are responsible for water activation and oxidation. Oxygen bound to three iridium centers (µ3-O) remains the dominant species in the bulk but do not participate directly in the electrocatalytic reaction, suggesting bulk oxidation is limited. In addition a high coverage of a µ1-OO (peroxo) species during the OER is excluded. Moreover, we provide the first photoelectron spectroscopic evidence in bulk electrolyte that the higher surface-to-bulk ratio in thinner electrodes enhances the material usage involving the precipitation of a significant part of the electrode surface and near-surface active species.

Unraveling mitotic protein networks by 3D multiplexed epitope drug screening.

Three-dimensional protein localization intricately determines the functional coordination of cellular processes. The complex spatial context of protein landscape has been assessed by multiplexed immunofluorescent staining or mass spectrometry, applied to 2D cell culture with limited physiological relevance or tissue sections. Here, we present 3D SPECS, an automated technology for 3D Spatial characterization of Protein Expression Changes by microscopic Screening. This workflow comprises iterative antibody staining, high-content 3D imaging, and machine learning for detection of mitoses. This is followed by mapping of spatial protein localization into a spherical, cellular coordinate system, a basis for model-based prediction of spatially resolved affinities of proteins. As a proof-of-concept, we mapped twelve epitopes in 3D-cultured spheroids and investigated the network effects of twelve mitotic cancer drugs. Our approach reveals novel insights into spindle fragility and chromatin stress, and predicts unknown interactions between proteins in specific mitotic pathways. 3D SPECS's ability to map potential drug targets by multiplexed immunofluorescence in 3D cell culture combined with our automated high-content assay will inspire future functional protein expression and drug assays.

Silylated Ge9 Clusters as New Ligands for Cyclic (Alkyl)amino and Mesoionic Carbene Copper Complexes.

The coordination of Ge9 Zintl clusters at (carbene)CuI moieties is explored, and the complexes [(CAAC)Cu]2[η3-Ge9{Si(TMS)3}2] (1), (CAAC)Cu[η3-Ge9{Si(TMS)3}3] (2), and (MIC)Cu[η3-Ge9{Si(TMS)3}3] (3) are compared with their known N-heterocyclic carbene (NHC) derivatives (A and B), where CAAC = cyclic (alkyl)amino carbene, MIC = mesoionic carbene, and TMS = trimethylsilane. In analogy to the NHC derivatives, the synthesis of 1-3 proceeds by single-step reactions of (CAAC)CuCl or (MIC)CuCl with the [Ge9R2]2- and [Ge9R3]- [R = Si(TMS)3] cluster ligands, respectively, and yields complexes of (carbene)CuI (carbene = CAAC, MIC) moieties exhibiting η3-coordination modes of the Ge9 deltahedron to the Cu atom. In 1, [Ge9R2]2- acts as a η3-bridging unit for two (CAAC)CuI moieties, and 2 and 3 feature single (carbene)CuI (CAAC and MIC) fragments η3-connected to [Ge9R3]- units. Analysis of the bond lengths in comparison with known examples shows a bond expansion within the coordinated Ge3 triangular faces for all (carbene)CuIGe9 complexes (carbene = NHC, MIC, CAAC). All compounds are characterized by single-crystal X-ray diffractometry, NMR spectroscopy [1H, 13C{1H}, and 29Si{1H}], electrospray ionization mass spectometry, elemental analysis (C, H, and N), and for the first time also by IR and Raman investigations (for 2 and 3). The new complexes add to the known NHC derivatives and extend the exploration of Ge9 clusters with carbene ligands at CuI atoms.

Anionic Siliconoids from Zintl Phases: R3 Si9 - with Six and R2 Si9 2- with Seven Unsubstituted Exposed Silicon Cluster Atoms (R=Si(tBu)2 H).

Neutral and anionic silicon clusters (siliconoids) are regarded as important model systems for bulk silicon surfaces. For 25 years their formation from binary alkali metal silicide phases has been proposed, but experimentally never realized. Herein the silylation of a silicide, leading to the anionic siliconoids (Si(tBu)2 H)3 Si9 - (1 a) and (Si(tBu)2 H)2 Si9 2- (2 a) with the highest known number of ligand-free silicon atoms is reported for the first time. The new anions are obtained in a one-step reaction of K12 Si17 /NH3 (liq.) and Si(tBu)2 HCl/THF. Electrospray ionization spectrometry and 1 H, 13 C, 29 Si, as well as 29 Si-HMBC (heteronuclear multiple bond correlation) NMR spectroscopy, confirm the attachment of three silyl groups at a [Si9 ]4- cluster under formation of 1 a, in accordance with calculated NMR shifts. During crystal growth the siliconoid di-anion 2 a is formed. The single-crystal X-ray structure determination reveals that two silyl groups are connected to the deltahedral Si9 cluster core, revealing seven unsubstituted exposed silicon cluster atoms with a hemispheroidal coordination. The negative charges -1 and -2 are delocalized over the six and seven siliconoid Si atoms in 1 a and 2 a, respectively.

[Survey of Specialist Pulmonary Medicine Health Care Structures for Patients with Interstitial Lung Disease in Nordrhein-Westfalen, Germany - A Pilot Project of the Western German Respiratory Society (WdGP)]. / Erfassung der pneumologisch-fachärztlichen Versorgungsstrukturen für Patienten mit interstitiellen Lungenerkrankungen in Nordrhein-Westfalen.

AIM OF THE STUDY: Survey of specialist pulmonary medicine health care structures for patients with interstitial lung disease (ILD) in Nordrhein-Westfalen, Germany. METHODS: The Western German Respiratory Society initiated a voluntary registration of ILD expert centers. Structural quality and processes were evaluated by questionnaire. RESULTS: 49 centers were registered, 46 allowed analysis of their center data (15 pulmonology specialist practices, 34 hospital pulmonology departments). Specialist practices saw a median of 360 ILD patients per year (26 % first diagnosis), hospital departments a median of 105 ILD patients per year (63 % first diagnosis). 10 centers diagnose more than 100 new ILD cases per year. Specialist practices report median 50 bronchoscopies per year, hospital departments median 1396. 78 % of the centers participate in a multidisciplinary ILD case conference. CONCLUSION: Several ILD expert centers were identified in Nordrhein-Westfalen. Outpatient care mainly involves the monitoring of ILD patients, inpatient services focus on complex initial diagnostics or cases with unusual disease behaviour. ILD centers meeting regional health care needs should be supported in their development.

Charged Si9 Clusters in Neat Solids and the Detection of [H2 Si9 ]2- in Solution: A Combined NMR, Raman, Mass Spectrometric, and Quantum Chemical Investigation.

Polyanionic silicon clusters are provided by the Zintl phases K4 Si4 , comprising [Si4 ]4- units, and K12 Si17 , consisting of [Si4 ]4- and [Si9 ]4- clusters. A combination of solid-state MAS-NMR, solution NMR, and Raman spectroscopy, electrospray ionization mass spectrometry, and quantum-chemical investigations was used to investigate four- and nine-atomic silicon Zintl clusters in neat solids and solution. The results were compared to 29 Si isotope-enriched samples. 29 Si-MAS NMR and Raman shifts of the phase-pure solids K4 Si4 and K12 Si17 were interpreted by quantum-chemical calculations. Extraction of [Si9 ]4- clusters from K12 Si17 with liquid ammonia/222crypt and their transfer to pyridine yields in a red solid containing Si9 clusters. This compound was characterized by elemental and EDX analyses and 29 Si-MAS NMR and Raman spectroscopy. Charged Si9 clusters were detected by 29 Si NMR in solution. 29 Si and 1 H NMR spectra reveal the presence of the [H2 Si9 ]2- cluster anion in solution.

Are psychophysiological arousal and self-reported emotional stress during an oncological consultation related to memory of medical information? An experimental study.

Patients forget 20-80% of information provided during medical consultations. The emotional stress often experienced by patients during consultations could be one of the mechanisms that lead to limited recall. The current experimental study therefore investigated the associations between (analog) patients' psychophysiological arousal, self-reported emotional stress and their (long term) memory of information provided by the physician. One hundred and eighty one cancer-naïve individuals acted as so-called analog patients (APs), i.e. they were instructed to watch a scripted video-recoding of an oncological bad news consultation while imagining themselves being in the patient's situation. Electrodermal and cardiovascular activity (e.g. skin conductance level and heart rate) were recorded during watching. Self-reported emotional stress was assessed before and after watching, using the STAI-State and seven Visual Analog Scales. Memory, both free recall and recognition, was assessed after 24-28 h. Watching the consultation evoked significant psychophysiological and self-reported stress responses. However, investigating the associations between 24 psychophysiological arousal measures, eight self-reported stress measures and free recall and recognition of information resulted in one significant, small (partial) correlation (r = 0.19). Considering multiple testing, this significant result was probably due to chance. Alternative analytical methods yielded identical results, strengthening our conclusion that no evidence was found for relationships between variables of interest. These null-findings are highly relevant, as they may be considered to refute the long-standing, but yet untested assumption that a relationship between stress and memory exists within this context. Moreover, these findings suggest that lowering patients' stress levels during the consultation would probably not be sufficient to raise memory of information to an optimal level. Alternative explanations for these findings are discussed.

ComEA is essential for the transfer of external DNA into the periplasm in naturally transformable Vibrio cholerae cells.

The DNA uptake of naturally competent bacteria has been attributed to the action of DNA uptake machineries resembling type IV pilus complexes. However, the protein(s) for pulling the DNA across the outer membrane of Gram-negative bacteria remain speculative. Here we show that the competence protein ComEA binds incoming DNA in the periplasm of naturally competent Vibrio cholerae cells thereby promoting DNA uptake, possibly through ratcheting and entropic forces associated with ComEA binding. Using comparative modeling and molecular simulations, we projected the 3D structure and DNA-binding site of ComEA. These in silico predictions, combined with in vivo and in vitro validations of wild-type and site-directed modified variants of ComEA, suggested that ComEA is not solely a DNA receptor protein but plays a direct role in the DNA uptake process. Furthermore, we uncovered that ComEA homologs of other bacteria (both Gram-positive and Gram-negative) efficiently compensated for the absence of ComEA in V. cholerae, suggesting that the contribution of ComEA in the DNA uptake process might be conserved among naturally competent bacteria.

[Exacerbation of COPD]. / Expertentreffen COPD: Exazerbation der COPD.

Acute worsenings of chronic obstructive pulmonary disease (COPD) were for a long time regarded as transient deteriorations, although occasionally life-threatening. No connection to disease progression was recognized. Data emerging during the last decade showed that patients had a considerably worse survival outcome after severe exacerbations. This insight was consolidated in 2012 by a large population-based cohort analysis. At present, severe exacerbations are regarded as key risk factors for COPD disease progression. The present article summarises the current knowledge on exacerbations of COPD, as delineated during an expert workshop in February 2017. It comprises pathogenic mechanisms, exacerbation triggers, the characteristics of frequent exacerbators, and the predictors of worse survival outcome. The role of comorbidities is considered more closely. The presentation of the pharmacotherapy of acute exacerbation is supplemented by an overview of ventilatory support. Finally, pharmacological and nonpharmacological preventive measures are summarised.

[Criteria for treating MRSA in sputum]. / Kriterien zur Behandlung von MRSA im Sputum?

Methicillin-resistant strains of Staphylococcus aureus (MRSA) are of particular significance for the management of patients with airway infections, since the disease course is often complicated and treatment rendered difficult by multiple resistance. Their prevalence is now slowly declining, but still alarmingly high. Hospital-acquired infections are predominant, but hospital-associated and community-acquired infections do occur, as do rare infections with livestock-acquired strains. Non-nosocomial strains are characterized by different pathogenic factors and a different spectrum of antibacterial resistance; they often have a threatening disease course. Anti-infectives with activity against MRSA are unusual and have particular toxicity profiles. On the other hand, MRSA colonization is eliminated spontaneously in healthy people and acute bronchitis is treatable by common oral antibiotics. However, chronic airway infection in bronchiectasis and other forms of structural airway damage requires a complex systemic and local treatment approach for pathogen elimination.

Norepinephrine modulates osteoarthritic chondrocyte metabolism and inflammatory responses.

OBJECTIVE: Norepinephrine (NE) was measured in synovial fluid of trauma patients and sympathetic nerve fibers were detected in healthy and osteoarthritic (OA) joint tissues indicating that cartilage pathophysiology might be influenced by sympathetic neurotransmitters. The aim of this study was to elucidate the mostly unknown role of NE in OA chondrocyte metabolism and inflammatory responses. METHODS: Articular cartilage was received after total knee replacement surgery from OA patients. Expression of adrenergic receptors (AR) and tyrosine hydroxylase (TH) was tested with end point polymerase chain reaction (PCR) and immunohistochemistry. 3-dimensional (3D) cell cultures were employed to analyze effects of NE on chondrocyte cell metabolism and the expression of interleukins (ILs), matrix metalloproteases (MMPs), tissue inhibitor of metalloproteases (TIMPs), glycosaminoglycan (GAG) and collagen II under non- and inflammatory conditions. Chondrocyte monolayer cultures were used to specify AR subtypes, to analyze cell cycle distribution and to determine catecholamines in cell culture supernatants. RESULTS: AR subtypes and TH were detected in chondrocytes, whereas NE was not released in measurable amounts. 10(-6) M NE reversed IL-1ß induced changes in IL-8, MMP-13, GAG and collagen II expression/production indicating for ß-AR signaling. Additionally, NE caused cell cycle slow down and decreased proliferation via ß-AR signaling. 10(-8) M NE increased the number of proliferating cells and induced apoptosis via α1-AR signaling. CONCLUSIONS: NE affects chondrocytes from OA cartilage regarding inflammatory response and its cell metabolism in a dose dependent manner. The sympathetic nervous system (SNS) may have a dual function in OA pathology with preserving a stable chondrocyte phenotype via ß-AR signaling and OA pathogenesis accelerating effects via α-AR signaling.

On the Reactivity of Silylated Ge9 Clusters: Synthesis and Characterization of [ZnCp*(Ge9 {Si(SiMe3 )3 }3 )], [CuPiPr3 (Ge9 {Si(SiMe3 )3 }3 )], and [(CuPiPr3 )4 {Ge9 (SiPh3 )2 }2 ].

We report on the synthesis of new derivatives of silylated clusters of the type [Ge9 (SiR3 )3 ]- (R = SiMe3 , Me = CH3 ; R = Ph, Ph = C6 H5 ) as well as on their reactivity towards copper and zinc compounds. The silylated cluster compounds were synthesized by heterogeneous reactions starting from the Zintl phase K4 Ge9 . Reaction of K[Ge9 {Si(SiMe3 )3 }3 ] with ZnCl2 leads to the already known dimeric compound [Zn(Ge9 {Si(SiMe3 )3 }3 )2 ] (1), whereas upon the reaction with [ZnCp*2 ] the coordination of [ZnCp*]+ to the cluster takes place (Cp*=1,2,3,4,5-pentamethylcyclopentadienyl) under the formation of [ZnCp*(Ge9 {Si(SiMe3 )3 }3 )] (2). A similar reaction leads to [CuPiPr3 (Ge9 {Si(SiMe3 )3 }3 )] (3) from [CuPiPr3 Cl] (iPr=isopropyl). Further we investigated the novel silylated cluster units [Ge9 (SiPh3 )3 ]- (4) and [Ge9 (SiPh3 )2 ]- (5), which could be identified by mass spectroscopy. Bis- and tris-silylated species can be synthesized by the respective stoichiometric reactions, and the products were characterized by ESI-MS and NMR experiments. These clusters show rather different reactivity. The reaction of the tris-silylated anion 4 with [CuPiPr3 Cl] leads to [(CuPiPr3 )3 Ge9 (SiPh3 )2 ]+ as shown from NMR experiments and to [(CuPiPr3 )4 {Ge9 (SiPh3 )2 }2 ] (6), which was characterized by single-crystal X-ray diffraction. Compound 6 shows a new type of coordination of the Cu atoms to the silylated Zintl clusters.

[Expert Meeting on COPD: Personalized Treatment of COPD - Wishful Thinking or Reality?] / Expertentreffen COPD: Personalisierte Therapie der COPD ­ Wunsch oder Wirklichkeit?

Chronic obstructive pulmonary disease (COPD) is considered to be a complex and heterogeneous disease comprising multiple components. Its clinical presentation, pattern of functional disturbance, disease presentation and pathology varies tremendously between individuals despite the common feature of incompletely reversible airflow obstruction. It is therefore widely accepted that COPD is characterized by discriminable phenotypes that represent specific patterns of these disease features. COPD phenotypes are believed to correlate with outcome parameters such as severity of symptoms, exacerbations, functional loss or death and to require different treatment algorithms.This survey is the result of presentations that were given during an expert conference. It highlights the significance of major comorbidities, genetic, morphologic and inflammatory COPD-phenotypes and their impact on disease progression and treatment modalities.

[Management of Adult Community-acquired Pneumonia and Prevention - Update 2016]. / Behandlung von erwachsenen Patienten mit ambulant erworbener Pneumonie und Prävention - Update 2016.

The present guideline provides a new and updated concept of treatment and prevention of adult patients with community-acquired pneumonia. It replaces the previous guideline dating from 2009.The guideline was worked out and agreed on following the standards of methodology of a S3-guideline. This includes a systematic literature search and grading, a structured discussion of recommendations supported by the literature as well as the declaration and assessment of potential conflicts of interests.The guideline has a focus on specific clinical circumstances, an update on severity assessment, and includes recommendations for an individualized selection of antimicrobial treatment as well as primary and secondary prevention.

Diagnosis and antimicrobial therapy of lung infiltrates in febrile neutropenic patients (allogeneic SCT excluded): updated guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Medical Oncology (DGHO).

Up to 25% of patients with profound neutropenia lasting for >10 days develop lung infiltrates, which frequently do not respond to broad-spectrum antibacterial therapy. While a causative pathogen remains undetected in the majority of cases, Aspergillus spp., Pneumocystis jirovecii, multi-resistant Gram-negative pathogens, mycobacteria or respiratory viruses may be involved. In at-risk patients who have received trimethoprim-sulfamethoxazole (TMP/SMX) prophylaxis, filamentous fungal pathogens appear to be predominant, yet commonly not proven at the time of treatment initiation. Pathogens isolated from blood cultures, bronchoalveolar lavage (BAL) or respiratory secretions are not always relevant for the etiology of pulmonary infiltrates and should therefore be interpreted critically. Laboratory tests for detecting Aspergillus galactomannan, ß-D-glucan or DNA from blood, BAL or tissue samples may facilitate the diagnosis; however, most polymerase chain reaction assays are not yet standardized and validated. Apart from infectious agents, pulmonary side-effects from cytotoxic drugs, radiotherapy or pulmonary involvement by the underlying malignancy should be included into differential diagnosis and eventually be clarified by invasive diagnostic procedures. Pre-emptive treatment with mold-active systemic antifungal agents improves clinical outcome, while other microorganisms are preferably treated only when microbiologically documented. High-dose TMP/SMX is first choice for treatment of Pneumocystis pneumonia, while cytomegalovirus pneumonia is treated primarily with ganciclovir or foscarnet in most patients. In a considerable number of patients, clinical outcome may be favorable despite respiratory failure, so that intensive care should be unrestrictedly provided in patients whose prognosis is not desperate due to other reasons.

Measurement of the position-dependent electrophoretic force on DNA in a glass nanocapillary.

The electrophoretic force on a single DNA molecule inside a glass nanocapillary depends on the opening size and varies with the distance along the symmetrical axis of the nanocapillary. Using optical tweezers and DNA-coated beads, we measured the stalling forces and mapped the position-dependent force profiles acting on DNA inside nanocapillaries of different sizes. We showed that the stalling force is higher in nanocapillaries of smaller diameters. The position-dependent force profiles strongly depend on the size of the nanocapillary opening, and for openings smaller than 20 nm, the profiles resemble the behavior observed in solid-state nanopores. To characterize the position-dependent force profiles in nanocapillaries of different sizes, we used a model that combines information from both analytical approximations and numerical calculations.