Publications by authors named "Tim Verhagen"

Airborne transmission is an important transmission route for the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Epidemiological data indicate that certain SARS-CoV-2 variants, like the omicron variant, are associated with higher transmissibility. We compared virus detection in air samples between hospitalized patients infected with different SARS-CoV-2 variants or influenza virus.

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A 47-year old male presented to the emergency department with a pneumomediastinum following a small penetrating wound to the neck.

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Various properties of water are affected by confinement as the space-filling of the water molecules is very different from bulk water. In our study, we challenged the creation of a stable system in which water molecules are permanently locked in nanodimensional graphene traps. For that purpose, we developed a technique, nitrocellulose-assisted transfer of graphene grown by chemical vapor deposition, which enables capturing of the water molecules below an atomically thin graphene membrane structured into a net of regular wrinkles with a lateral dimension of about 4 nm.

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Article Synopsis
  • The study aimed to evaluate the effectiveness of chest CT and RT-PCR tests for COVID-19 in asymptomatic surgical patients.
  • The research involved 2,093 patients across 14 centers, revealing a low positive yield of COVID-19 cases—1.5% for combined testing, 0.7% for CT, and 1.1% for RT-PCR.
  • Results indicated that while preoperative screening helped ensure safety in surgeries, the value of chest CT testing was minimal compared to RT-PCR, particularly as community COVID-19 prevalence increased.
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Characterization of the type and density of defects in two-dimensional (2D) transition metal dichalcogenides (TMDs) is important as the nature of these defects strongly influences the electronic and optical properties of the material, especially its photoluminescence (PL). Defect characterization is not as straightforward as it is for graphene films, where the D and D' Raman scattering modes easily indicate the density and type of defects in the graphene layer. Thus, in addition to the Raman scattering analysis, other spectroscopic techniques are necessary to perform detailed characterization of atomically thin TMD layers.

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Topographic corrugations, such as wrinkles, are known to introduce diverse physical phenomena that can significantly modify the electrical, optical and chemical properties of two-dimensional materials. This range of assets can be expanded even further when the crystal lattices of the walls of the wrinkle are aligned and form a superlattice, thereby creating a high aspect ratio analogue of a twisted bilayer or multilayer - the so-called twisted wrinkle. Here we present an experimental proof that such twisted wrinkles exist in graphene monolayers on the scale of several micrometres.

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The control of graphene's topography at the nanoscale level opens up the possibility to greatly improve the surface functionalization, change the doping level or create nanoscale reservoirs. However, the ability to control the modification of the topography of graphene on a wafer scale is still rather challenging. Here we present an approach to create well-defined nanowrinkles on a wafer scale using nitrocellulose as the polymer to transfer chemical vapor deposition grown graphene from the copper foil to a substrate.

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Objective: Up to 8% of patients undergoing surgery via a Pfannenstiel incision may develop chronic inguinal pain. This type of pain is frequently caused by inguinal nerve entrapment and may strongly interfere with daily functioning. We report our long term experience of a step up approach using tender point infiltration and surgical neurectomy for intractable neuropathic post-Pfannenstiel groin pain.

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The emission of light in two-dimensional (2-D) layered hybrid organic lead halide perovskites, namely (R-NH)PbX, can be effectively tuned using specific building blocks for the perovskite formation. Herein this behaviour is combined with a non-covalent graphene functionalization allowing excellent selectivity and spatial resolution of the perovskite film growth, promoting the formation of hybrid 2-D perovskite : graphene heterostructures with uniform coverage of up to centimeter scale graphene sheets and arbitrary shapes down to 5 μm. Using cryo-Raman microspectroscopy, highly resolved spectra of the perovskite phases were obtained and the Raman mapping served as a convenient spatially resolved technique for monitoring the distribution of the perovskite and graphene constituents on the substrate.

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Graphene is extremely sensitive to optical, electrical and mechanical stimuli, which cause a significant variation of the band structure, thus the physiochemical properties. In our work, we report on changes of strain and doping in graphene grown by chemical vapor deposition on copper and transferred onto a BaTiO(1 0 0) (BTO) single-crystal. The BTO is known as a ferroelectric material, which undergoes several thermoelastic martensitic phase transitions when it is cooled from 300 K to 10 K.

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We present an approach that allows for the preparation of well-defined large arrays of graphene wrinkles with predictable geometry. Chemical vapor deposition grown graphene transferred onto hexagonal pillar arrays of SiO with sufficiently small interpillar distance forms a complex network of two main types of wrinkle arrangements. The first type is composed of arrays of aligned equidistantly separated parallel wrinkles propagating over large distances, and originates from line interfaces in the graphene, such as thin, long wrinkles and graphene grain boundaries.

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Objective: The aim of this study was to investigate long-term groin pain and inguinal hernia recurrence rates of 2 types of mesh and to describe the evolution of postoperative groin sensory disturbances.

Summary Of Background Data: Some patients with an inguinal hernia develop chronic pain following open mesh insertion. Previous trials comparing a semi-resorbable, self-gripping Progrip mesh with a standard sutured polypropylene mesh found conflicting results regarding recurrence rates and residual groin pain.

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Objective: This study compares tender point infiltration (TPI) and a tailored neurectomy as the preferred treatment for chronic inguinodynia after inguinal herniorraphy.

Background: Some 11% of patients develop chronic discomfort after open inguinal herniorraphy. Both TPI and neurectomy have been suggested as treatment options, but evidence is conflicting.

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Controlled wrinkling of single-layer graphene (1-LG) at nanometer scale was achieved by introducing monodisperse nanoparticles (NPs), with size comparable to the strain coherence length, underneath the 1-LG. Typical fingerprint of the delaminated fraction is identified as substantial contribution to the principal Raman modes of the 1-LG (G and G'). Correlation analysis of the Raman shift of the G and G' modes clearly resolved the 1-LG in contact and delaminated from the substrate, respectively.

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Background: Some patients develop chronic groin pain after a Lichtenstein hernia repair. Previous studies have demonstrated beneficial effects of removal of entrapped inguinal nerves or a meshectomy in patients with chronic pain after open inguinal hernia mesh repair. Factors determining success following this remedial surgery are unknown.

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