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Abstract Background There are various reconstructive methods after total sternectomy. Reproducibility is scarce due to overall small patient numbers. Therefore we present a standardized, interdisciplinary approach for thoracic and plastic surgery. Methods Four patients underwent interdisciplinary chest wall reconstruction with STRATOS® titanium bars and myocutaneous vastus lateralis muscle free flap in our center. Results All patients reported chest wall stability after reconstruction. They reported good quality of life, no dyspnea, prolonged pain or impairment in lung function from rigid reconstruction. FEV1/FVC was overall better after surgery. Secondary wound healing was not impaired and there was no implant defect in follow up. Conclusions We recommend an interdisciplinary surgical approach in chest wall reconstruction after total sternectomy. The combination of rigid reconstruction with titanium bars and a myocutaneous vastus lateralis muscle free flap renders excellent results in patient satisfaction and is objectifiable via spirometry.

After failed conservative therapy or in the absence of any intervention, a rupture of the digital subcutaneous extensor tendon at the distal interphalangeal (DIP) joint, known as mallet finger, may lead to a chronic extension deficit due to excessive scarring and tendon elongation. Various surgical techniques to restore the extension of the distal phalanx have been proposed, but an optimal approach has not yet been established. To tighten the extensor tendon, a purse-string suture can be applied. Although it has shown efficacy, it can result in significant bulging and scar formation. Using the “abbreviato” technique, the elongated part of the extensor tendon is excised, and the tendon is re-sutured. Also, tenodesis has been described, particularly in pediatric cases. In this retrospective follow-up study, we aimed to investigate if the step-plasty procedure previously described by Baumeister provides comparable, if not superior, functional and aesthetic outcomes compared to existing techniques for patients with chronic mallet finger. In this retrospective study, a consecutive series of 68 patients with chronic mallet fingers was enrolled. Patients were treated surgically using step-plasty of the respective extensor tendon. After skin incision and tenolysis, the elongated extensor tendon was incised in a Z-like fashion and stepwise resected in the transverse portion of the Z. The functional and aesthetic effects of this step-plasty technique were compared with results of 44 patients previously treated using purse-string sutures of the extensor tendon and evaluated using Crawford’s and Levante’s criteria. In all patients undergoing the step-plasty procedure, the extension deficit was significantly reduced from an average of 42 degrees preoperatively to 11 degrees postoperatively. In contrast, the control group treated by purse-string sutures showed a slightly higher postoperative extension deficit of 15 degrees. According to Levante’s criteria, the results of our step-plasty procedure were significantly better than those achieved with purse-string sutures. Our study demonstrated that the treatment of older or chronic subcutaneous extensor tendon ruptures using the step-plasty technique led to a significant reduction in extension deficits. According to Levante’s criteria, the postoperative outcome was significantly better in comparison to the purse-string suture technique. Additionally, no skin resection was required to improve the extension capability of the distal finger joint, compared to established surgical procedures.

PURPOSEThis study aimed to evaluate the safety and outcome of image-guided embolization for treating arteriovenous malformations (AVMs) of the hand using ethylene-vinyl alcohol copolymer (EVOH).METHODSA retrospective, multicenter cohort of 15 patients with AVMs of the hand treated with 35 imageguided embolotherapies using EVOH was investigated. Clinical history, symptomatology, and imaging findings were assessed to evaluate clinical outcome (symptom-free, partial relief of pain, no improvement of pain, and clinical progression despite embolization), lesion devascularization (total, 100%; near-total, 90%-99%; substantial, 70%-90%; partial, 30%-70%; and failure, 0%-30%), and peri- and postprocedural complication rates (major complications classified according to CIRSE guidelines). Substratification analysis was performed with respect to the involvement of different anatomical compartments and the injected volume of the embolic agent.RESULTSPatients were treated for pain (93.3%), skin ulceration (46.7%), and local bleeding (33.3%). The mean number of embolotherapies was 2.3 (±1.1) in 3 patients, a planned surgical resection was conducted after embolization. Clinical outcome after a median follow-up of 18 months revealed an overall response of 11/15 patients (73.3%). Imaging at last follow-up revealed 70%- 99% reduced vascularization in 12/15 patients (80%) including 2 patients (13.3%) with a neartotal devascularization of 90%-99%. Peri- and postprocedural complications occurred in 8.5% and 31.5%, respectively, including 17.1% major complications, in 1 case requiring a previously unplanned resection. Involvement of the finger was associated with increased rates of persistent symptoms compared to the other groups (P=.049). No significant difference between the embolic agent volume injected and complication rates was found (P=.372).CONCLUSIONImage-guided embolization using EVOH-based liquid embolic agents is effective for treating AVMs of the hand in the mid-term.

Summary:. Postoperative adhesions can deteriorate clinical outcomes in tendon repair surgery significantly. Thus, the use of artificial membranes as a tendon sheath substitute has become popular and well studied in the last years. We performed a case series of three patients using a novel synthetic membrane (Suprathel) for complex reconstructive surgery and traumatic tendon repair surgery. All patients recovered well with no significant adverse effects and showed good clinical function afterward. Therefore, we concluded that Suprathel might be another potential candidate to prevent postoperative peritendinous adhesions. Further studies will be necessary to determine the effect of this bioresorbable barrier membrane.

Background: Microsurgical tissue transfer revolutionized reconstructive surgery after extensive trauma, oncological resections, and severe infections. Complex soft tissue reconstructions are increasingly performed in multimorbid and elderly patients. Therefore, it is crucial to investigate whether these patients benefit from these complex procedures. Objective: To evaluate the outcome for multimorbid patients who underwent microsurgical soft tissue reconstruction and to identify potential risk factors that may increase mortality. Methods: This single-center study retrospectively analyzed prospectively collected data of patients receiving free gracilis (GM) or latissimus dorsi muscle (LDM) flap reconstruction between September 2017 and December 2021. Cases were divided into two groups (dead vs. alive), depending on patient survival. Patient demographics, comorbidities and medication, perioperative details, free flap outcome, as well as microcirculation were determined. Results: A total of 151 flaps (LDM, n = 67; GM, n = 84) performed in 147 patients with a mean age of 61.15 ± 17.5 (range 19–94) years were included. A total of 33 patients (22.45%) passed away during the study period. Deceased patients were significantly older (Alive: 58.28 ± 17.91 vs. Dead: 71.39 ± 11.13; p = 0.001), were hospitalized significantly longer (Alive: 29.66 ± 26.97 vs. Dead: 36.88 ± 15.04 days; p = 0.046) and suffered from cardiovascular (Alive: 36.40% vs. Dead: 66.70%; p = 0.002) and metabolic diseases (Alive: 33.90% vs. Dead: 54.50%; p = 0.031) more frequently, which corresponded to a significantly higher ASA Score (p = 0.004). Revision rates (Alive: 11.00% vs. Dead: 18.20%; p = 0.371) and flap loss (Alive: 3.39% vs. Dead: 12.12%; p = 0.069) were higher in patients that died by the end of the study period. Conclusions: Free flap transfer is safe and effective, even in multimorbid patients. However, patient age, comorbidities, preoperative ASA status, and medication significantly impact postoperative patient survival in the short- and mid-term and must, therefore, be taken into account in preoperative decision-making and informed consent.

Background:. There exist various operative approaches for the treatment of trapeziometacarpal joint osteoarthritis. The aim of this study was to compare the results of Lundsborg’s resection arthroplasty (RA) with implantation of a total endoprosthesis. Patients and Methods:. In this 2-center study, we retrospectively analyzed 71 patients with symptomatic osteoarthritis of the carpometacarpal I joint stage III according to the Eaton-Littler classification. Thirty-two patients underwent a Lundsborg’s RA group, and 39 patients received a total endoprosthesis of the carpometacarpal I joint (TEP group). We evaluated operative time, DASH score, postoperative time until resolution of symptoms, pain level, pinch force, and satisfaction with the treatment. Results:. Both groups had a similar mean length of follow-up of 42 months (TEP group) and 36 months (RA group). The final DASH score was significantly better in the TEP-group (10.1 versus 21.5 in the RA group; P ≤ 0.05). Also, the time interval from surgery till absence of any pain (1.5 versus 5.9 months) and the time of inability to work (6 versus 21 weeks) were significantly shorter for the TEP group compared with the RA group (P ≤ 0.05). The pinch force, pain intensity, and the satisfaction with the treatment were comparable (P > 0.05). The duration of the operation was significantly shorter in the RA group (31 min versus 65 min in the TEP group; P ≤ 0.05). Conclusion:. Both techniques resulted in improved function of the operated hand and a clear reduction of symptoms. However, the implantation of a total endoprosthesis seems to have advantages, given a significantly better DASH score and a significantly shorter time until resolution of symptoms.

The striatum projection neurons are striatonigral and striatopallidal medium sized-spiny neurons (MSNs) that preferentially express D1 (D1R) and D2 (D2R) dopamine receptors, respectively. It is generally assumed that these neurons are physically intermingled, without cytoarchitectural organization although this has not been tested. To address this question we used BAC transgenic mice expressing enhanced green fluorescence (EGFP) under the control of Drd1a or Drd2 promoter and spatial point pattern statistics. We demonstrate that D1R- and D2R-expressing MSNs are randomly distributed in most of the dorsal striatum, whereas a specific region in the caudal striatum, adjacent to the GPe, appears to lack neurons expressing markers for indirect pathway neurons. This area comprises almost exclusively D1R-expressing MSNs. These neurons receive excitatory inputs from the primary auditory cortex and the medial geniculate thalamic nucleus and a rich dopamine innervation. This area contains cholinergic and GABAergic interneurons but apparently no D2R/A2aR modulation because no fluorescence was detected in the neuropil in Drd2-EGFP, Drd2-Cre and Adora-Cre BAC reporter mice. This striatal area that expresses calbindin-D28K, VGluT1 and 2, is poor in µ opiate receptors and preproenkephalin. Altogether, the differences observed in D1R-MSNs, D2R-MSNs and interneurons densities, as well as the anatomical segregation of D1R- and D2R/A2aR-expressing MSNs suggest that there are regional differences in the organization of the striatum.

The nucleus accumbens (NAc) is a critical brain region involved in many reward-related behaviors. The NAc comprises major compartments the core and the shell, which encompass several subterritories. GABAergic medium-sized spiny neurons (MSNs) constitute the output neurons of the NAc core and shell. While the functional organization of the NAc core outputs resembles the one described for the dorsal striatum, a simple classification of the NAc shell neurons has been difficult to define due to the complexity of the compartmental segregation of cells. We used a variety of BAC transgenic mice expressing enhanced green fluorescence (EGFP) or the Cre-recombinase (Cre) under the control of the promoter of dopamine D1, D2, and D3 receptors and of adenosine A2a receptor to dissect the microanatomy of the NAc. Moreover, using various immunological markers we characterized in detail the distribution of MSNs in the mouse NAc. In addition, cell-type specific ERK phosphorylation in the NAc subterritories was analyzed following acute administration of SKF81297 (a D1R-like agonist), quinpirole (a D2R-like agonist), apomorphine (a non-selective DA receptor agonist), raclopride (a D2R-like antagonist), and psychostimulant drugs, including cocaine and d-amphetamine. Each drug generated a unique topography and cell-type specific activation of ERK in the NAc. Our results show the existence of marked differences in the receptor expression pattern and functional activation of MSNs within the shell subterritories. This study emphasizes the anatomical and functional heterogeneity of the NAc, which will have to be considered in its further study.

The granuloma is an elaborated aggregate of immune cells found in non-infectious as well asinfectious diseases. It is a hallmark of tuberculosis (TB). Predominantly thought as a host-drivenstrategy to constrain the bacilli and prevent dissemination, recent discoveries indicatethe granuloma can also be modulated into an efficient tool to promote microbial pathogenesis.The aim of future studies will certainly focus on better characterization of the mechanismsdriving the modulation of the granuloma functions. Here, we provide unique perspectivesfrom both the innate and adaptive immune system in the formation and the role of the TBgranuloma. As macrophages (Mϕs) comprise the bulk of granulomas, we highlight theemerging concept of Mϕ polarization and its potential impact in the microbicide response, andother activities, that may ultimately shape the fate of granulomas. Alternatively, we shed lighton the ability of B cells to influence inflammatory status within the granuloma.

In the principal neurons of striatum (medium spiny neurons, MSNs), cAMP pathway is primarily activated through the stimulation of dopamine D1 and adenosine A2A receptors, these receptors being mainly expressed in striatonigral and striatopallidal MSNs, respectively. Since cAMP signaling pathway could be altered in various physiological and pathological situations, including drug addiction and Parkinson’s disease, it is of crucial importance to identify the molecular components involved in the activation of this pathway. In MSNs, cAMP pathway activation is not dependent on the classical Gs GTP-binding protein but requires a specific G protein subunit heterotrimer containing Galpha-olf/beta2/gamma7 in particular association with adenylate cyclase type 5. This assembly forms an authentic functional signaling unit since loss of one of its members leads to defects of cAMP pathway activation in response to D1 or A2A receptor stimulation, inducing dramatic impairments of behavioral responses dependent on these receptors. Interestingly, D1 receptor-dependent cAMP signaling is modulated by the neuronal levels of Galpha-olf, indicating that Galpha-olf represents the rate-limiting step in this signaling cascade and could constitute a critical element for regulation of D1 receptor responses. In both Parkinsonian patients and several animal models of Parkinson’s disease, the lesion of dopamine neurons produces a prolonged elevation of Galpha-olf levels. This observation gives an explanation for the cAMP pathway hypersensitivity to D1 stimulation, occurring despite an unaltered D1 receptor density. In conclusion, alterations in the highly specialized assembly of Galpha-olf/beta2/gamma7 subunits can happen in pathological conditions, such as Parkinson’s disease, and it could have important functional consequences in relation to changes in D1 receptor signaling in the striatum.

In contrast to most other brain regions, in the striatum the output neurons (the medium-sized spiny neurons, MSNs) are GABAergic and act by inhibiting their targets. The standard model of the basal ganglia is built on the segregation of information processing in the direct and indirect pathways, which act in opposing directions to control movement. The MSNs participating in these two pathways can be identified according to their projection sites and the proteins they express. The differential expression of two of the five known dopamine receptor subtypes, D1 and D2, in the two populations of MSNs is of particular importance, since it confers to dopamine the ability to exert opposite functional modulation on the direct and indirect pathways. However, beyond this simple view of the striatal output organization, anatomical studies questioned the segregation of direct and indirect projections to the SNr, while other studies disclosed variable degrees of overlapping expression of dopamine receptor subtypes in striatal MSNs. New ways to address these issues have emerged recently, using mouse models in which specific populations of striatal neurons are genetically tagged. Here, we review classical and recent studies supporting the segregation of striatonigral and striatopallidal neurons. We also consider this issue at a functional level by focusing on the regulation of striatal signaling pathways in the two populations of MSNs, which clearly emphasize their profound differences. We discuss the anatomical and functional evidence challenging some aspects of this segregation and outline questions that are still to be addressed.

Vapor detection is a noncontact sampling method, which is a less invasive means of explosives screening than physical swiping. Explosive vapor detection is a challenge due to the low levels of vapors available for detection. This study demonstrates that the parts-per-quadrillion sensitivity of atmospheric flow tube-mass spectrometry (AFT-MS) combined with a high-volume air sampler enables standoff detection of trace explosives vapor at distances of centimeters to meters. Standoff detection of explosives vapor was possible both upstream and downstream of the vapor source relative to room air currents. RDX vapor from a saturated source was detected at up to 2.5 m. Vapors from RDX residue and nitroglycerin residue were detected at distances up to 0.5 m. The sampling can be optimized by accounting for air movement in the room or environment, which could further extend standoff detection distances. Using AFT-MS with a high-volume sampler could also be effective for standoff vapor detection of drugs and additional chemical threats and could be useful for security screening applications such as at mail facilities, border crossings, and security checkpoints., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

There is a need for non-contact, real-time vapor detection of drugs to combat illicit transportation and help curb the opioid epidemic. The low volatility of drugs, like fentanyl, makes room temperature vapor detection of illicit drugs challenging, but feasible by atmospheric flow tube-mass spectrometry (AFT-MS). AFT-MS is a non-contact vapor detection approach capable of ultra-trace detection of drugs, including fentanyl and its analogs at low parts-per-quadrillion (ppq v ) levels. The determination of vapor pressure values of fentanyl is necessary to understand potential vapor concentrations that may be available for detection. In this paper, vapor pressures of fentanyl free base and fentanyl hydrochloride salt (a common form of the illicit drug) were measured as a function of temperature at or near ambient conditions using the transpiration (gas saturation) method and AFT-MS. Based on our measurements, the vapor pressure of fentanyl at 25 °C is 9.0 × 10 -14 atm (90 ppq v ), and the vapor pressure of fentanyl hydrochloride at 25 °C is 1.8 × 10 -17 atm (0.018 ppq v ). We also demonstrate non-contact, real-time vapor detection of fentanyl. Preconcentration of vapors can further extend the detection capabilities. The collection, desorption, and detection of fentanyl vapors at ambient conditions was demonstrated for sampling times of seconds to an hour resulting in increased signal. AFT-MS is a viable detection method of fentanyl and other drugs for screening of packages and cargo.

Proton affinity is a major factor in the atmospheric pressure chemical ionization of illicit drugs. The detection of illicit drugs by mass spectrometry and ion mobility spectrometry relies on the analytes having greater proton affinities than background species. Evaluating proton affinities for fentanyl and its analogues is informative for predicting the likelihood of ionization in different environments and for optimizing the compounds' ionization and detection, such as through the addition of dopant chemicals. Herein, density functional theory was used to computationally determine the proton affinity and gas-phase basicity of 15 fentanyl compounds and several relevant molecules as a reference point. The range of proton affinities for the fentanyl compounds was from 1018 to 1078 kJ/mol. Fentanyl compounds with the higher proton affinity values appeared to form a bridge between the oxygen on the amide and the protonated nitrogen on the piperidine ring based on models and calculated bond distances. Experiments with fragmentation of proton-bound clusters using atmospheric flow tube-mass spectrometry (AFT-MS) provided estimates of relative proton affinities and showed proton affinity values of fentanyl compounds >1000 kJ/mol, which were consistent with the computational results. The high proton affinities of fentanyl compounds facilitate their detection by ambient ionization techniques in complex environments. The detection limits of the fentanyl compounds with AFT-MS are in the low femtogram range, which demonstrates the feasibility of trace vapor drug detection.

The goal of this study was to determine the physicochemical properties of a variety of geologic materials using inverse gas chromatography (IGC) by varying probe gas selection, temperature, carrier gas flow rate, and humidity. This is accomplished by measuring the level of interaction between the materials of interest and known probe gases. Identifying a material's physicochemical characteristics can help provide a better understanding of the transport of gaseous compounds in different geologic materials or between different geological layers under various conditions. Our research focused on measuring the enthalpy (heat) of adsorption, Henry's constant, and diffusion coefficients of a suite of geologic materials, including two soil types (sandy clay-loam and loam), quartz sand, salt, and bentonite clay, with various particle sizes. The reproducibility of IGC measurements for geologic materials, which are inherently heterogeneous, was also assessed in comparison to the reproducibility for more homogeneous synthetic materials. This involved determining the variability of physicochemical measurements obtained from different IGC approaches, instruments, and researchers. For the investigated IGC-determined parameters, the need for standardization became apparent, including the need for application-relevant reference materials. The inherent physical and chemical heterogeneities of soil and many geologic materials can make the prediction of sorption properties difficult. Characterizing the properties of individual organic and inorganic components can help elucidate the primary factors influencing sorption interactions in more complex mixtures. This research examined the capabilities and potential challenges of characterizing the gas sorption properties of geologic materials using IGC.

Explosives are often used in industry, geology, mining, and other applications, but it is not always clear what remains after a detonation or the fate and transport of any residual material. The goal of this study was to determine to what extent intact molecules of high explosive (HE) compounds are detectable and quantifiable from post-detonation dust and particulates in a field experiment with varied topography. We focused on HMX (1,3,5,7-Tetranitro-1,3,5,7-tetrazocane), which is less studied in field detonation literature, as the primary explosive material and RDX (1,3,5-Trinitroperhydro-1,3,5-triazine) as the secondary material. The experiment was conducted at Site 300, Lawrence Livermore National Laboratory's Experimental Test Site, in California, USA. Two 20.4 kg and one 40.8 kg above ground explosions (primarily comprised of LX-14, an HMX-based polymer-bonded high explosive) were detonated on an open-air firing area on separate days. The complex terrain of the firing area (e.g., buildings, berm, low-height obstacles) was advantageous to study HE deposition in relation to plume dynamics. Three types of samples were collected up to 100 m away from each shot: surface swipes of aluminum plates, surface swipes of fixed objects, and filters from air samples. We used atmospheric flow tube-mass spectrometry (AFT-MS) to quantify picogram levels of molecular residue of HE material in the post-detonation dust. An aliquot of sample extract in methanol (e.g., 1 μL of 0.5 mL) was placed onto a resistive material and then thermally desorbed into the AFT-MS. We successfully detected and quantified both HMX and RDX in many of the samples. Based on mass (pg) detected and solution dilution, we back-calculated the mass collected on the swipe or filter (ng per sample). The aerial distribution of molecular residue was consistent with the path of the plume, which was strongly determined by wind speed and direction at the time of each shot. The quantity of material detected appeared to correlate more with distance from the shot and the wind conditions than with shot size. This study demonstrates that the picogram detection levels of AFT-MS are well-suited for quantification of analytes (e.g., HMX and RDX) in environmental samples., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Knowing accurate saturated vapor pressures of explosives at ambient conditions is imperative to provide realistic boundaries on available vapor for ultra-trace detection. In quantifying vapor content emanating from low-volatility explosives, we observed discrepancies between the quantity of explosive expected based on literature vapor pressure values and the amount detected near ambient temperatures. Most vapor pressure measurements for low-volatility explosives, such as RDX (1,3,5-trinitro-1,3,5-triazinane) and HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane), have been made at temperatures far exceeding 25 °C and linear extrapolation of these higher temperature trends appears to underestimate vapor pressures near room temperature. Our goal was to measure vapor pressures as a function of temperature closer to ambient conditions. We used saturated RDX and HMX vapor sources at controlled temperatures to produce vapors that were then collected and analyzed via atmospheric flow tube-mass spectrometry (AFT-MS). The parts-per-quadrillion (ppq v ) sensitivity of AFT-MS enabled measurement of RDX vapor pressures at temperatures as low as 7 °C and HMX vapor pressures at temperatures as low as 40 °C for the first time. Furthermore, these vapor pressures were corroborated with analysis of vapor generated by nebulizing low concentration solutions of RDX and HMX. We report updated vapor pressure values for both RDX and HMX. Based on our measurements, the vapor pressure of RDX at 25 °C is 3 ± 1 × 10 -11 atm (i.e., 30 parts per trillion by volume, ppt v ), the vapor pressure of HMX is 1.0 ± 0.6 × 10 -14 atm (10 ppq v ) at 40 °C and, with extrapolation, HMX has a vapor pressure of 1.0 ± 0.6 × 10 -15 atm (1.0 ppq v ) at 25 °C.

Real-time, non-contact detection of illicit drugs is a desirable goal for the interdiction of these controlled substances, but the relatively low vapor pressures of such species present a challenge for trace vapor detection technologies. The introduction of atmospheric flow tube-mass spectrometry (AFT-MS), which has previously been demonstrated to detect gas-phase analytes at low parts-per-quadrillion levels for explosives and organophosphorus compounds, also enables the potential for non-contact drug detection. With AFT-MS, direct vapor detection of cocaine and methamphetamine from ∼5 μg residues at room temperature is demonstrated herein. Furthermore, thermal desorption of low- to sub-picogram levels of cocaine, methamphetamine, fentanyl, and heroin is observed via AFT-MS using a carrier flow rate of several L min -1 of air. These low levels can permit non-contact sampling through collection of vapor, effectively preconcentrating the analyte before desorption and analysis. Quantitative evaluation of the thermal desorption approach has yielded limits of detection (LODs) on the order of 10 fg for cocaine and fentanyl, 100 fg for methamphetamine, and 1.6 pg for heroin. The LOD for heroin was lowered to 300 fg by using tributyl phosphate as a dopant to form a proton-bound heterodimer with heroin. When used with AFT-MS, the intentional formation of specific drug-dopant adducts has the potential to enhance detection limits and selectivity of additional drug species. Species that are prone to form adducts present a challenge to analysis, but that difficulty can be overcome by the intentional addition of a dopant. Molecules unlikely to form adducts will remain essentially unimpacted, but the adduct-forming species will interact with the dopant to compress the analyte signal into a single peak. This approach would be valuable in the application of non-contact screening for illicit substances via vapor collection followed by thermal desorption for analysis.

Complex interactions between roots and soil provide the nutrients and physical support required for robust plant growth. Yet, visualizing the root-soil interface is challenged by soil's opaque scattering characteristics. Herein, we describe methods for using optical coherence tomography (OCT) to provide non-destructive 3D and cross-sectional root imaging not available with traditional bright-field microscopy. OCT is regularly used for bioimaging, especially in ophthalmology, where it can detect retinal abnormalities. Prior use of OCT in plant biology has focused on surface defects of above-ground tissues, predominantly in food crops. Our results show OCT is also viable for detailed, in situ study of living plant roots. Using OCT for direct observations of root growth in soil can help elucidate key interactions between root morphology and various components of the soil environment including soil structure, microbial communities, and nutrient patches. Better understanding of these interactions can guide efforts to improve plant nutrient acquisition from soil to increase agricultural efficiency as well as better understand drivers of plant growth in natural systems.

Research in the deep terrestrial biosphere is driven by interest in novel biodiversity and metabolisms, biogeochemical cycling, and the impact of human activities on this ecosystem. As this interest continues to grow, it is important to ensure that when subsurface investigations are proposed, materials recovered from the subsurface are sampled and preserved in an appropriate manner to limit contamination and ensure preservation of accurate microbial, geochemical, and mineralogical signatures. On February 20th, 2014, a workshop on "Trends and Future Challenges in Sampling The Deep Subsurface" was coordinated in Columbus, Ohio by The Ohio State University and West Virginia University faculty, and sponsored by The Ohio State University and the Sloan Foundation's Deep Carbon Observatory. The workshop aims were to identify and develop best practices for the collection, preservation, and analysis of terrestrial deep rock samples. This document summarizes the information shared during this workshop.