At present, there are few technologies which enable the detection, identification and viability analysis of protozoan pathogens including Cryptosporidium and/or Giardia at the single (oo)cyst level. ...We report the use of Microfluidic Impedance Cytometry (MIC) to characterise the AC electrical (impedance) properties of single parasites and demonstrate rapid discrimination based on viability and species. Specifically, MIC was used to identify live and inactive C. parvum oocysts with over 90% certainty, whilst also detecting damaged and/or excysted oocysts. Furthermore, discrimination of Cryptosporidium parvum, Cryptosporidium muris and Giardia lamblia, with over 92% certainty was achieved. Enumeration and identification of (oo)cysts can be achieved in a few minutes, which offers a reduction in identification time and labour demands when compared to existing detection methods.
Although malaria is the world's most life-threatening parasitic disease, there is no clear understanding of how certain biophysical properties of infected cells change during the malaria infection ...cycle. In this article, we use microfluidic impedance cytometry to measure the dielectric properties of Plasmodium falciparum-infected red blood cells (i-RBCs) at specific time points during the infection cycle. Individual parasites were identified within i-RBCs using green fluorescent protein (GFP) emission. The dielectric properties of cell sub-populations were determined using the multi-shell model. Analysis showed that the membrane capacitance and cytoplasmic conductivity of i-RBCs increased along the infection time course, due to membrane alterations caused by parasite infection. The volume ratio occupied by the parasite was estimated to vary from less than 10% at earlier stages, to approximately 90% at later stages. This knowledge could be used to develop new label-free cell sorting techniques for sample pre-enrichment, improving diagnosis.
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer lacking specific biomarkers that can be correlated to disease onset, promotion and progression. To assess whether tumor cell ...electrophysiology may serve as a marker for PDAC tumorigenicity, we use multi-frequency impedance cytometry at high throughput (∼350 cells/s) to measure the electrical phenotype of single PDAC tumor cells from xenografts, which are derived from primary pancreatic tumors versus those from liver metastases of different patients. A novel phase contrast metric based on variations in the high and low frequency impedance phase responses that is related to electrophysiology of the cell interior is found to be systematically altered as a function of tumorigenicity. PDAC cells of higher tumorigenicity exhibited lowered interior conductivity and enhanced permittivity, which is validated by the dielectrophoresis on the respective cell types. Using genetic analysis, we suggest the role of dysregulated Na+ transport and removal of Ca2+ ions from the cytoplasm on key oncogenic KRAS-driven processes that may be responsible for lowering of the interior cell conductivity. We envision that impedance cytometry can serve as a tool to quantify phenotypic heterogeneity for rapidly stratifying tumorigenicity. It can also aid in protocols for dielectrophoretic isolation of cells with a particular phenotype for prognostic studies on patient survival and to tailor therapy selection to specific patients.
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•High-throughput (∼350 cells/s) impedance cytometry to measure ∼10,000 cells/sample.•Samples of patient-derived pancreatic tumor xenografts of varying tumorigenicity.•Impedance phase due to electrophysiology of cell interior varies with tumorigenicity.•Lowered interior conductivity and enhanced permittivity for cells of higher tumorigenicity.•Validated based on level of positive dielectrophoresis and its crossover frequency.
Abstract Liquid Ar (LAr) and liquid Xe (LXe) time projection chambers (TPCs) are used for many applications in neutrino physics and direct dark matter searches. The performance of these detectors, ...particularly dual-phase ones, depends very strongly on the efficiency for detecting the far ultraviolet (FUV) scintillation light. Such detection is particularly challenging for LAr, in which the strongest scintillation feature is observed at a wavelength of 127 nm (175 nm for LXe). The current mainstream approach is covering the optical surfaces with a wavelength shifter, which absorbs de FUV light and emits at wavelengths that overlap with the optical band, where commercial devices have higher detection efficiency. This work presents coatings designed to enhance the optical properties of the detector materials and to be an alternative to the current technique. In particular, two possible coatings are proposed: narrowband and broadband FUV reflective coatings. The narrowband coatings are tuned at the FUV scintillation light. They provide a large reflectance at the design angle; additionally, these coatings are naturally transparent at longer wavelengths, which might be useful to selectively detect the wavelength of interest. Their performance is evaluated taking into account the refractive index of LAr and as a function of the angle of incidence. The same calculations are performed for an aluminium-based broadband mirror. Finally, the effect on reflectance of submerging both sorts of mirrors at liquid nitrogen temperature is presented.
Mental ill-health is a public health threat that is prevalent throughout the United States. Tens of millions of Americans have been diagnosed along the continuum of mental ill-health, and many more ...millions of family members and friends are indirectly affected by the pervasiveness of mental ill-health. Issues such as access and the societal stigma related to mental health issues serve as deterrents to patients receiving their necessary care. However, technological advances have shown the potential to increase access to mental health services for many patients.
We diagnosed and treated a case of Ludwig's angina in a 45-year-old man who had edema of the floor of mouth and the tongue along with bilateral submandibular sialadenitis and sialolithiasis. We ...secured the patient's airway via nasal fiberoptic intubation in the surgical intensive care unit and administered intravenous antibiotics. The edema subsided, and the patient was extubated on the third postoperative day and discharged shortly thereafter. To our knowledge, this is the first reported case of a patient with bilateral submandibular sialadenitis and sialolithiasis presenting as Ludwig's angina. Despite the decreasing incidence of this disease, Ludwig's angina remains an important disease process because a failure to control the airway can have disastrous consequences. Proper diagnosis, airway control, antibiotic therapy, and occasionally surgical management are essential to ensure the safety of the patient.
Objective To evaluate the role of the incudostapedial joint (ISJ) angle in stapes prosthesis size selection and crimping.
Methods The ISJ of 13 cadaveric human temporal bones were photographed, then ...measured using computer‐aided design software. The relationship of ISJ angle to prosthesis length was modeled. A literature review evaluated factors contributing to stapedectomy failure.
Results The mean ISJ angle was 93.0° (SD = 8.3°) (range, 75.0°–104.0°). The mean ISJ angle deviation from 90° was 7.35° (SD = 4.45°) (range, 0.3°–15.0°). The mean distance along the incus accessible for prosthesis placement was 3.21 mm (SD = 0.55 mm) (range, 2.00–4.00 mm).
Conclusions Significant deviation of the ISJ angle from 90° was found (P <.0001). The length along the incus accessible for prosthesis placement was sufficient to result in errors in prosthesis size selection and crimping with only small variations in the ISJ angle. Incorrect prosthesis sizing and crimping are frequently associated with stapedectomy failure. Variations in ISJ anatomy should be considered when selecting stapes prostheses lengths and may affect crimping technique.
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