Generation and Implementation of Continuum Infrared Pulses for Broadband Detection in 2D IR Spectroscopy.

In recent years, new methods of generating continuum mid-infrared pulses through filamentation in gases have been developed for ultrafast time-resolved infrared vibrational spectroscopy. The generated infrared pulses can have thousands of wavenumbers of bandwidth, spanning the entire mid-IR region while retaining pulse length below 100 fs. This technology has had a significant impact on problems involving ultrafast structural dynamics in congested spectra with broad features, such as those found in aqueous solutions and molecules with strong intermolecular interactions. This study describes the recent advances in generating and characterizing these pulses and the practical aspects of implementing these sources for broadband detection in transient absorption and 2D IR spectroscopy.

Lanthanide transport in angstrom-scale MoS2-based two-dimensional channels.

Rare earth elements (REEs), critical to modern industry, are difficult to separate and purify, given their similar physicochemical properties originating from the lanthanide contraction. Here, we systematically study the transport of lanthanide ions (Ln3+) in artificially confined angstrom-scale two-dimensional channels using MoS2-based building blocks in an aqueous environment. The results show that the uptake and permeability of Ln3+ assume a well-defined volcano shape peaked at Sm3+. This transport behavior is rooted from the tradeoff between the barrier for dehydration and the strength of interactions of lanthanide ions in the confinement channels, reminiscent of the Sabatier principle. Molecular dynamics simulations reveal that Sm3+, with moderate hydration free energy and intermediate affinity for channel interaction, exhibit the smallest dehydration degree, consequently resulting in the highest permeability. Our work not only highlights the distinct mass transport properties under extreme confinement but also demonstrates the potential of dialing confinement dimension and chemistry for greener REEs separation.

Anomalously enhanced ion transport and uptake in functionalized angstrom-scale two-dimensional channels.

Emulating angstrom-scale dynamics of the highly selective biological ion channels is a challenging task. Recent work on angstrom-scale artificial channels has expanded our understanding of ion transport and uptake mechanisms under confinement. However, the role of chemical environment in such channels is still not well understood. Here, we report the anomalously enhanced transport and uptake of ions under confined MoS2-based channels that are ~five angstroms in size. The ion uptake preference in the MoS2-based channels can be changed by the selection of surface functional groups and ion uptake sequence due to the interplay between kinetic and thermodynamic factors that depend on whether the ions are mixed or not prior to uptake. Our work offers a holistic picture of ion transport in 2D confinement and highlights ion interplay in this regime.

Development and Characterization of Electrodes for Surface-Specific Attenuated Total Reflection Two-Dimensional Infrared Spectroelectrochemistry.

Electrochemical interfaces still have remaining mysteries surrounding the interfacial region of the electrical double layer, despite being prevalent throughout the energy and water remediation industries. The electrical double layer is where many important dynamic processes such as catalysis and electron transfer occur. The goal of this work is to study the electrical double layer with two-dimensional infrared (2D IR) spectroscopy to experimentally access the details of the structural dynamics of this complex environment. However, there are several experimental challenges to applying 2D IR spectroscopy to this application, such as assuring the surface specificity of the spectrum, optimizing the signal strength while minimizing spectral distortions from dispersion and Fano line shapes, and selecting electrode materials that are both sufficiently IR compatible and conductive. Here we will discuss various considerations when designing 2D IR experiments of electrode interfaces utilizing several substrates and experimental configurations and demonstrate a robust method for 2D IR experiments of electrode interfaces under applied potential that combines nonconducting Si ATR wafers with conductive ITO and thin nanostructured films of plasmonically active Au functionalized with 3-mercapto-2-butanone (MCB). We show that layered electrodes on thin Si ATR wafers with MCB are sensitive to applied potential and that the distortions in the linear and 2D IR spectra are heavily dependent on the morphology of the Au surface.

Vibrational Probe at the Electrochemical Interface: Dependence on Plasmon Coupling and Potential of the Lineshape in Two-Dimensional Infrared Spectroscopy.

Two-dimensional infrared spectroscopy of vibrational probes at an electrode surface shows promise for studying the structural dynamics at an active electrochemical interface. This interface is a complex environment where the solution structures in response to the applied potential. A strategy for achieving the necessary monolayer sensitivity is to use a plasmonically active electrode, which enhances the electromagnetic fields that produce the spectroscopic response. Here, we show how the coupling between the plasmon and the vibrations of the molecular monolayer impacts the FTIR and 2D IR spectroscopy, with an emphasis on the electrochemical potential difference spectra. We show how mixing between the vibrational and plasmonic states gives rise to the distortions that are observed in these measurements. This provides an important step toward 2D IR measurements of vibrational probes at the electrochemical interface as a tool for probing the structural dynamics in the double layer.

Strong H-bonding from Zeolite BroÌ·nsted Acid Site to Water: Origin of the Broad IR Doublet.

Hydrogen bonding between water molecules and zeolite BroÌ·nsted acid sites (BAS) has received much attention due to the significant influence of water on the adsorption and catalytic properties of these widely used porous materials. When a single water molecule is adsorbed at the BAS, the zeolite O-H stretch vibration decreases in frequency and splits into two extraordinarily broad bands peaked near 2500 and 2900 cm-1 in the infrared (IR) spectrum. This broad doublet feature is the predominant IR signature used to identify and interpret water-BAS H-bonding at low hydration levels, but the origin of the band splitting is not well understood. In this study, we used broadband two-dimensional infrared (2D IR) spectroscopy to investigate zeolite HZSM-5 prepared with a single water molecule per BAS. We find that the 2D IR spectrum is not explained by the most common interpretation of Fermi resonance coupling between the stretch and the bend of the BAS OH group, which predicts intense excited-state transitions that are absent from the experimental results. We present an alternative model of a double-well proton stretch potential, where the band splitting is caused by excited-state tunneling through the proton-transfer barrier. This one-dimensional model reproduces the basic experimental pattern of transition frequencies and amplitudes, suggesting that the doublet bands may originate from a highly anharmonic potential in which the excited state proton wave functions are delocalized over the H-bond between zeolite BAS and adsorbed H2O. Additional details about molecular orientation and coordination of the adsorbed water molecule are also resolved in the 2D IR spectroscopy.

Retrospective Study of Treatment Patterns and Natural History of Patients with T1a/b N0 Triple-Negative Breast Cancers: A Single-Institution Experience.

INTRODUCTION: T1a/b, node-negative (node-), triple-negative breast cancers (TNBCs) are underrepresented in randomized drug-approving clinical trials. Given their low incidence, the clinicopathological features, natural history, and treatment patterns of these tumors remain insufficiently understood. METHODS: We conducted a single-institution retrospective cohort study of patients with T1a/b, N0, M0 TNBCs. Deidentified patient- and tumor-related data were collected and summarized. Kruskal-Wallis, χ2, or Fisher exact tests were used to evaluate associations of interest. Kaplan-Meier methods, log-rank tests, and Cox's proportional hazards models were applied for survival analyses. RESULTS: Of 108 cases of node- TNBCs measuring ≤2 cm, 34 node- T1a/b tumors were included in our analysis. All cases had an intermediate to high histological grade, and most had a Ki-67 score of ≥20%. All patients received adjuvant chemotherapy, and many underwent mastectomy (47%). Docetaxel combined with cyclophosphamide was the most common adjuvant chemotherapy regimen (75%). We did not observe significant associations between improved outcomes and treatment with anthracycline-containing regimens. Among patients with node- pT1a/b tumors, the estimated 3-year recurrence-free survival (RFS) and distant RFS rates were both 96.3% (95% CI: 76.5-99.5), and the overall survival rate was estimated to be 100% (95% CI: 100-100). There were no cases of local recurrences observed. CONCLUSIONS: In our cohort, all patients with T1a/b node- TNBCs were treated with adjuvant chemotherapy and had favorable outcomes even when treated with anthracycline-sparing regimens.

Is Clostridium perfringens epsilon toxin associated with multiple sclerosis?

Clostridium perfringens epsilon toxin is associated with enterotoxaemia in livestock. More recently, it is proposed to play a role in multiple sclerosis (MS) in humans. Compared to matched controls, strains of C. perfringens which produce epsilon toxin are significantly more likely to be isolated from the gut of MS patients and at significantly higher levels; similarly, sera from MS patients are significantly more likely to contain antibodies to epsilon toxin. Epsilon toxin recognises the myelin and lymphocyte (MAL) protein receptor, damaging the blood-brain barrier and brain cells expressing MAL. In the experimental autoimmune encephalomyelitis model of MS, the toxin enables infiltration of immune cells into the central nervous system, inducing an MS-like disease. These studies provide evidence that epsilon toxin plays a role in MS, but do not yet fulfil Koch's postulates in proving a causal role.

Amplification of mid-IR continuum for broadband 2D IR spectroscopy.

We report the generation and characterization of microjoule level, broad bandwidth femtosecond pulses in the mid-infrared (MIR) using optical parametric amplification of continuum MIR seed pulses in GaSe. The signal (3 µm) and idler (6 µm) pulses have energies of 6 µJ and 3 µJ with bandwidths of ∼950 cm-1 and 650 cm-1 FWHM and pulse lengths of 34 fs and 80 fs. Broadband 2D IR spectra of O-H and N-H transitions are acquired with the signal beam demonstrating the capabilities of this source for cross peak and line shape measurements.

Robotic-assisted foregut surgery is associated with lower rates of complication and shorter post-operative length of stay.

BACKGROUND: Two of the most common foregut operations are laparoscopic Heller myotomy and laparoscopic Nissen fundoplication. Robotic assistance, compared to standard laparoscopic approach, may potentially grant surgeons advantages such as enhanced visualization and dexterity. This study compares patient outcomes for Heller myotomy (HM) and Nissen fundoplication (NF) when performed laparoscopically versus robotically. METHODS: A retrospective review of patients at a single institution who underwent laparoscopic or robotic-assisted HM or NF from January 2019 to July 2022 was conducted. 123 HM (72 laparoscopic, 51 robotic-assisted) and 92 NF (62 laparoscopic, 30 robotic-assisted) were performed by three surgeons. Outcomes investigated were operative time, hospital length of stay, pre- and post-operative imaging, resolution of symptoms at 30 days, resolution of symptoms at 90 days, and complications. RESULTS: In the HM cohorts, the average operative time was longer in the robotic cohort (127 min robotic versus 108 min laparoscopic, p < 0.01). However, overall complication rates (p < 0.05) were lower, and hospital length of stay was shorter in the robotic group (1.5 days compared to 2.7 days, p < 0.001). In the NF cohorts, there was no significant difference in operative time. However, hospital length of stay was shorter in the robotic group (1.54 days compared to 2.7 days, p < 0.001) with otherwise similar outcomes. There was no difference in the rate of post-operative resolution of symptoms or need for additional interventions in either HM or NF. CONCLUSION: Robotic-assisted HM and NF are associated with shorter hospital stays compared to their respective laparoscopic approaches. Robotic-assisted HM also has a lower rate of complications. Our findings suggest that robotic assistance may be beneficial for shortening hospital length of stay and decreasing complications for certain surgeries specific to Foregut surgery.

Virtual Microscopy Tagging and Its Benefits for Students, Faculty, and Interprofessional Programs Alike.

Background Over the years, due to technological innovations in medical education, virtual microscopy has become a popular tool used to teach histology. The Virtual Microscopy Project is a faculty and student collaborative project at the University of South Florida (USF) Health to transfer and update online histology slides from an outdated viewer to a completely new viewer. Methodology The project goal is to better facilitate the educational experience for students and faculty through the implementation of updated technology and features. Results At USF Health, multiple programs use the online histology slide viewer to teach normal histology. The previous website's organization and lack of additional features severely hindered opportunities for personalized education; users could not write any notes, circle or point to important features, or easily search for specific organs or tissue. An updated website user interface and additional instructional features will improve the students' accessibility and overall quality of their learning. The updated viewer will be more integrated into the USF Health Morsani College of Medicine (MCOM) curriculum, providing faculty with organized and readily available material. USF MCOM has faculty integration directors to create a balanced curriculum that can be reviewed by faculty for consistency and accuracy. Adding this same organizational structure to the online microscopy viewer will assist directors in forming and modifying the curriculum and may also provide them with additional resources for their education delivery. Conclusion The Virtual Microscopy Project hopes to produce an accessible, user-friendly online microscopy viewer that is beneficial to students for learning, to faculty for teaching/curriculum planning, and to medical education as a whole.

From Networked to Isolated: Observing Water Hydrogen Bonds in Concentrated Electrolytes with Two-Dimensional Infrared Spectroscopy.

Superconcentrated electrolytes have emerged as a promising class of materials for energy storage devices, with evidence that high voltage performance is possible even with water as the solvent. Here, we study the changes in the water hydrogen bonding network induced by the dissolution of lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) in concentrations ranging from the dilute to the superconcentrated regimes. Using time-resolved two-dimensional infrared spectroscopy, we observe the progressive disruption of the water-water hydrogen bond network and the appearance of isolated water molecules interacting only with ions, which can be identified and spectroscopically isolated through the intermolecular cross-peaks between the water and the TFSI- ions. Analyzing the vibrational relaxation of excitations of the H2O stretching mode, we observe a transition in the dominant relaxation path as the bulk-like water vanishes and is replaced by ion-solvation water with the rapid single-step relaxation of delocalized stretching vibrations into the low frequency modes being replaced by multistep relaxation through the intramolecular H2O bend and into the TFSI- high frequency modes prior to relaxing to the low frequency structural degrees of freedom. These results definitively demonstrate the absence of vibrationally bulk-like water in the presence of high concentrations of LiTFSI and especially in the superconcentrated regime, while additionally revealing aspects of the water hydrogen bond network that have been difficult to discern from the vibrational spectroscopy of the neat liquid.

Exchange-Mediated Transport in Battery Electrolytes: Ultrafast or Ultraslow?

Understanding the mechanisms of charge transport in batteries is important for the rational design of new electrolyte formulations. Persistent questions about ion transport mechanisms in battery electrolytes are often framed in terms of vehicular diffusion by persistent ion-solvent complexes versus structural diffusion through the breaking and reformation of ion-solvent contacts, i.e., solvent exchange events. Ultrafast two-dimensional (2D) IR spectroscopy can probe exchange processes directly via the evolution of the cross-peaks on picosecond time scales. However, vibrational energy transfer in the absence of solvent exchange gives rise to the same spectral signatures, hiding the desired processes. We employ 2D IR on solvent resonances of a mixture of acetonitrile isotopologues to differentiate chemical exchange and energy-transfer dynamics in a comprehensive series of Li+, Mg2+, Zn2+, Ca2+, and Ba2+ bis(trifluoromethylsulfonyl)imide electrolytes from the dilute to the superconcentrated regime. No exchange phenomena occur within at least 100 ps, regardless of the ion identity, salt concentration, and presence of water. All of the observed spectral dynamics originate from the intermolecular energy transfer. These results place the lower experimental boundary on the ion-solvent residence times to several hundred picoseconds, much slower than previously suggested. With the help of MD simulations and conductivity measurements on the Li+ and Zn2+ systems, we discuss these results as a continuum of vehicular and structural modalities that vary with concentration and emphasize the importance of collective electrolyte motions to ion transport. These results hold broadly applicable to many battery-relevant ions and solvents.

Benefits of implementing student-led review and mock examinations in the medical undergraduate gross anatomy curriculum.

Anatomy consists of material that continually defines a student's undergraduate medical curriculum, and thus attaining a solid understanding of it is critical for academic success. Student exposure to anatomy prior to matriculation to the United States (US) medical school is highly variable, with some first introduced to the material in medical school. As a result, students without foundation in anatomy can struggle with adapting to the self-directed learning style that is required to excel with a prosection-based (i.e. hands-off analysis of a cadaver previously dissected by a professional) approach. In this study, second-year US medical students who have previously excelled in the first-year courses at the University of South Florida Morsani College of Medicine (in collaboration with faculty advisors) designed and offered a mock practical examination that mirrors the official practical exam specific to each course: a timed practical examination using dissected human cadavers and radiological imaging to assess anatomical knowledge, followed by a review session. Since the mock practical and review session was designed from a student's perspective, the material could be tailored to specifically address topics that students historically have struggled with. Students who participated in the mock practical and associated review sessions reported feeling more confident than their peers who did not participate. In addition, they significantly outperformed their peers on the official practical examination, independent of any demographic factors or educational background. This study demonstrates the benefits of incorporating peer-assisted learning (PAL) into the anatomical component of the medical school curriculum.

Characterization of Acetonitrile Isotopologues as Vibrational Probes of Electrolytes.

Acetonitrile has emerged as a solvent candidate for novel electrolyte formulations in metal-ion batteries and supercapacitors. It features a bright local C≡N stretch vibrational mode whose infrared (IR) signature is sensitive to battery-relevant cations (Li+, Mg2+, Zn2+, Ca2+) both in pure form and in the presence of water admixture across a full possible range of concentrations from the dilute to the superconcentrated regime. Stationary and time-resolved IR spectroscopy thus emerges as a natural tool to study site-specific intermolecular interactions from the solvent perspective without introducing an extrinsic probe that perturbs solution morphology and may not represent the intrinsic dynamics in these electrolytes. The metal-coordinated acetonitrile, water-separated metal-acetonitrile pair, and free solvent each have a distinct vibrational signature that allows their unambiguous differentiation. The IR band frequency of the metal-coordinated acetonitrile depends on the ion charge density. To study the ion transport dynamics, it is necessary to differentiate energy-transfer processes from structural interconversions in these electrolytes. Isotope labeling the solvent is a necessary prerequisite to separate these processes. We discuss the design principles and choice of the CD313CN label and characterize its vibrational spectroscopy in these electrolytes. The Fermi resonance between 13C≡N and C-D stretches complicates the spectral response but does not prevent its effective utilization. Time-resolved two-dimensional (2D) IR spectroscopy can be performed on a mixture of acetonitrile isotopologues and much can be learned about the structural dynamics of various species in these formulations.

Imaging Utilization Patterns and Injury Characteristics Associated with Electric Standing Scooters in a Major Urban Area.

BACKGROUND: The recent proliferation of electric standing scooters in major urban areas of the United States has been accompanied by injuries of varying severity and nature, representing a growing public health concern. OBJECTIVE: Our aim was to characterize imaging utilization patterns for injuries associated with electric scooter (e-scooter) use, including their initial emergency department (ED) management. METHODS: We conducted a retrospective review of the electronic medical record for all patients presenting to affiliated EDs for e-scooter-related injuries between July 2018 and April 2020. Demographics, date and time of presentation, imaging study type, resultant injury, and procedural details were recorded. RESULTS: Ninety-seven patients were included; mean age was 27.6 years. Of these, 55 patients (57%) had injuries identified on imaging and 40% of all imaging studies were positive. Most identified injuries (61%) were musculoskeletal, with a small number of neurological (2%) and genitourinary (1%) injuries. The highest prevalence of presentations occurred in August; most patients (72%) presented between 3 pm and 1 am and granular peaks were between 12 am and 1 am and 5 pm and 6 pm. CONCLUSIONS: Patients presenting with e-scooter injuries have a high likelihood of injury to the radial head, nasal bone, and malleoli. Emergency physicians should be especially vigilant for injuries in these areas at presentation. Visceral injuries are uncommon but may be severe enough to warrant surgery.

Lineshape Distortions in Internal Reflection Two-Dimensional Infrared Spectroscopy: Tuning across the Critical Angle.

Reflection mode two-dimensional infrared spectroscopy (R-2DIR) has recently emerged as a tool that expands the utility of ultrafast IR spectroscopy toward a broader class of materials. The impact of experimental configurations on the potential distortions of the transient reflectance (TR) spectra has not been fully explored, particularly in the vicinity of the critical angle θc and through the crossover from total internal reflection to partial reflection. Here we study the impact on the spectral lineshape of a dilute bulk solution as θc is varied across the incident angle by tuning the refractive index of the solvent. We demonstrate the significance of several distortions, including the appearance of phase twisted lineshapes and apparent changes in the spectral inhomogeneity, and show how these distortions impact the interpretation of the TR and R-2DIR spectroscopies.

Carbon Monoxide Poisoning With Concomitant Mucosal Injury and Chemical Pneumonitis Using Sulfuric and Formic Acids in a Self-Harm Attempt.

The intentional liberation of carbon monoxide through the dehydration of formic acid has been reported with increasing frequency in the literature as a method of self-harm. Online forums have popularized this method of self-harm due to the ease of access of the required reagents, as well as the ability to perform the reaction under ambient conditions. The basis of this method of suicide is the use of sulfuric acid as a dehydrating agent, leading to the decomposition of formic acid into carbon monoxide gas. In addition to the exposure to carbon monoxide liberated by this reaction, the relatively high vapor pressure of formic acid can inadvertently lead to its inhalation and subsequently cause damage to the aerodigestive tract. We report a 21-year-old male who presented with manifestations of acute carbon monoxide poisoning and concomitant chemical pneumonitis. Increased awareness and understanding of this method of self-harm is critical in ensuring appropriate precautions are taken when caring for these individuals.