Broadband micro-transient absorption spectroscopy enabled by improved lock-in amplification.

Recent breakthroughs in material development have increased the demand for characterization methods capable of probing nanoscale features on ultrafast time scales. As the sample reduces to atomically thin levels, an extremely low-level signal limits the feasibility of many experiments. Here, we present an affordable and easy-to-implement solution to expand the maximum sensitivity of lock-in detection systems used in transient absorption spectroscopy by multiple orders of magnitude. By implementation of a tuned RC circuit to the output of an avalanche photodiode, electric pulse shaping allows for vastly improved lock-in detection. Furthermore, a carefully designed "peak detector" circuit provides additional pulse shaping benefits, resulting in even more lock-in detection signal enhancement. We demonstrate the improvement of lock-in detection with each of these schemes by performing benchmark measurements of a white-light continuum signal and micro-transient absorption spectroscopy on a few-layer transition metal dichalcogenide sample. Our results show the practicality of ultrafast pump-probe spectroscopy for many high-sensitivity experimental schemes.

CT-guided blood tattoo for thoracoscopic excision of lung lesions in pediatric patients.

BACKGROUND: To describe a single-institutional experience with an innovative technique using CT-guided injection of autologous blood for localization of nonpleural-based pulmonary nodules prior to thoracoscopic excisional biopsy in pediatric patients. METHODS: A retrospective review of all patients under the age of 18 with lung lesions suspected to be malignant that were not pleural-based lesions and were not of adequate size to visualize at thoracoscopy, who underwent CT-guided blood tattoo (CGBT) localization between 2006-2019. CGBT was performed under general anesthesia by injecting 0.5-10 mL of autologous blood into the area of the lesions. The patients were then immediately transferred from interventional radiology to the operating room for thoracoscopic excision of the lesion. Demographics, location of lesions, indication for biopsy, and pathology were reviewed. RESULTS: In eleven pediatric patients (ages ranging from 4-18 years), preoperative CGBT localization of pulmonary nodules resulted in successful thoracoscopic excisional biopsy. All resections were diagnostic and 82% (9/11 cases) represented a metastatic malignancy as confirmed by pathology. Malignant nodules ranged from 2 to 14 mm in size, while a 13 mm nodule in a patient with history of AML was determined to be an organizing pneumonia and a 12 mm nodule in a second patient revealed a caseating granuloma consistent with Crohn's disease. One patient with a failed attempt at excisional biopsy without preoperative localization then underwent CGBT one week later with successful thoracoscopic excision of the nodule. CONCLUSIONS: CT-guided blood tattoo is a safe option for localization of nonpleural-based lung nodules prior to thoracoscopic excision in pediatric patients.

A pilot study on the management and outcomes of self-poisoning in a rural Ugandan Emergency Centre.

INTRODUCTION: The Global Emergency Care Collaborative and Nyakibale Hospital in Rukungiri opened the first functional emergency centre in rural Uganda. We investigated decontamination, management and outcomes of poisoned patients in the emergency centre. METHODS: An electronic database started recording charts from 24 March 2012. A search for diagnoses concerning self-poisoning was performed from 24 March 2012 to 30 December 2013 and 192 charts were found and de-identified. Data collection included: age, sex, poison and duration, intent, vital signs, physical examination, decontamination, antidote use and follow-up status. RESULTS: From 24 March 2012 to 30 December 2013 poisoning accounted for 96 patient encounters. Of these, 33 were associated with alpha-2 agonists and 16 were associated with organophosphorous or carbamate pesticides. The post-decontamination fatality rate was 5.7%. The fatality rate of those without decontamination was 8.3%. Of those who were given atropine, 38.8% had no known indication. Of the 96 patient encounters, there were seven deaths; six were due to pesticides. DISCUSSION: In resource-limited settings where antidotes and resuscitative capabilities are scarce, decontamination needs to be studied further. Repeat atropine use without indication may lead to depletion of an essential antidote. Future directions include a public health education programme and an algorithm to help guide clinical decisions.

NS5A inhibitors unmask differences in functional replicase complex half-life between different hepatitis C virus strains.

Hepatitis C virus (HCV) RNA is synthesized by the replicase complex (RC), a macromolecular assembly composed of viral non-structural proteins and cellular co-factors. Inhibitors of the HCV NS5A protein block formation of new RCs but do not affect RNA synthesis by pre-formed RCs. Without new RC formation, existing RCs turn over and are eventually lost from the cell. We aimed to use NS5A inhibitors to estimate the half-life of the functional RC of HCV. We compared different cell culture-infectious strains of HCV that may be grouped based on their sensitivity to lipid peroxidation: robustly replicating, lipid peroxidation resistant (LPOR) viruses (e.g. JFH-1 or H77D) and more slowly replicating, lipid peroxidation sensitive (LPOS) viruses (e.g. H77S.3 and N.2). In luciferase assays, LPOS HCV strains declined under NS5A inhibitor therapy with much slower kinetics compared to LPOR HCV strains. This difference in rate of decline was not observed for inhibitors of the NS5B RNA-dependent RNA polymerase suggesting that the difference was not simply a consequence of differences in RNA stability. In further analyses, we compared two isoclonal HCV variants: the LPOS H77S.3 and the LPOR H77D that differ only by 12 amino acids. Differences in rate of decline between H77S.3 and H77D following NS5A inhibitor addition were not due to amino acid sequences in NS5A but rather due to a combination of amino acid differences in the non-structural proteins that make up the HCV RC. Mathematical modeling of intracellular HCV RNA dynamics suggested that differences in RC stability (half-lives of 3.5 and 9.9 hours, for H77D and H77S.3, respectively) are responsible for the different kinetics of antiviral suppression between LPOS and LPOR viruses. In nascent RNA capture assays, the rate of RNA synthesis decline following NS5A inhibitor addition was significantly faster for H77D compared to H77S.3 indicating different half-lives of functional RCs.

The pulpal anesthetic efficacy of articaine versus lidocaine in dentistry: a meta-analysis.

BACKGROUND: The authors evaluated published evidence from controlled clinical trials regarding the efficacy of two local anesthetic solutions in providing successful pulpal anesthesia. METHODS: The authors searched MEDLINE and Embase databases to identify peer-reviewed randomized controlled trials in which researchers directly compared articaine and lidocaine local anesthetic solutions in adult participants. They extracted study characteristics and outcomes data as a basis for meta-analysis. They completed subgroup analyses for both infiltration and mandibular inferior alveolar block anesthetic techniques. RESULTS: Articaine solutions had a probability of achieving anesthetic success superior to that of lidocaine, with an odds ratio of 2.44 (95 percent confidence interval [CI], 1.59-3.76; P < .0001). The greater odds ratio for articaine increased to 3.81 (95 percent CI, 2.71-5.36; P < .00001) when the authors analyzed only infiltration data. There was weaker, but still significant, evidence of articaine's being superior to lidocaine for mandibular block anesthesia, with an odds ratio of 1.57 (95 percent CI, 1.12-2.21; P = .009), and no difference when the authors considered only symptomatic teeth. CLINICAL IMPLICATIONS: Research evidence supports using articaine versus lidocaine for achieving pulpal anesthesia when the infiltration mode of administration is used. It is premature to recommend articaine for mandibular block anesthesia in cases involving irreversible pulpitis.