Simultaneous Two- and Three-Photon Deep Imaging of Autofluorescence in Bacterial Communities

The intrinsic fluorescence of bacterial samples has a proven potential for label-free bacterial characterization, monitoring bacterial metabolic functions, and as a mechanism for tracking the transport of relevant components through vesicles. The reduced scattering and axial confinement of the excitation offered by multiphoton imaging can be used to overcome some of the limitations of single-photon excitation (e.g., scattering and out-of-plane photobleaching) to the imaging of bacterial communities. In this work, we demonstrate in vivo multi-photon microscopy imaging of Streptomyces bacterial communities, based on the excitation of blue endogenous fluorophores, using an ultrafast Yb-fiber laser amplifier. Its parameters, such as the pulse energy, duration, wavelength, and repetition rate, enable in vivo multicolor imaging with a single source through the simultaneous two- and three-photon excitation of different fluorophores. Three-photon excitation at 1040 nm allows fluorophores with blue and green emission spectra to be addressed (and their corresponding ultraviolet and blue single-photon excitation wavelengths, respectively), and two-photon excitation at the same wavelength allows fluorophores with yellow, orange, or red emission spectra to be addressed (and their corresponding green, yellow, and orange single-photon excitation wavelengths). We demonstrate that three-photon excitation allows imaging over a depth range of more than 6 effective attenuation lengths to take place, corresponding to an 800 micrometer depth of imaging, in samples with a high density of fluorescent structures.

Extended focal depth Fourier domain optical coherence microscopy with a Bessel-beam - LP02 mode - from a higher order mode fiber

We present a robust fiber-based setup for Bessel-like beam extended depth-of-focus Fourier-domain optical coherence microscopy, where the Bessel-like beam is generated in a higher order mode fiber module. In this module a stable guided LP₀₂ core mode is selectively excited by a long period grating written in the higher order mode fiber. Imaging performance of this system in terms of lateral resolution and depth of focus was analyzed using samples of suspended microbeads and compared to the case where illumination is provided by the fundamental LP₀₁ mode of a single mode fiber. Illumination with the LP₀₂ mode allowed for a lateral resolution down to 2.5 µm as compared to 4.5 µm achieved with the LP₀₁ mode of the single mode fiber. A three-fold enhancement of the depth of focus compared to a Gaussian beam with equally tight focus is achieved with the LP₀₂ mode. Analysis of the theoretical lateral point spread functions for the case of LP₀₁ and LP₀₂ illumination agrees well with the experimental data. As the design space of waveguides and long-period gratings allows for further optimization of the beam parameters of the generated Bessel-like beams in an all-fiber module, this approach offers a robust and yet flexible alternative to free-space optics approaches or the use of conical fiber tips.

Analysis of intensity correlation enhanced plasmonic structured illumination microscopy

We propose to enhance the performance of localized plasmon structured illumination microscopy (LP-SIM) via intensity correlations. LP-SIM uses sub-wavelength illumination patterns to encode high spatial frequency information. It can enhance the resolution up to three-fold before gaps in the optical transfer function (OTF) support arise. For blinking fluorophores or for quantum antibunching, an intensity correlation analysis induces higher harmonics of the illumination pattern and enlarges the effective OTF. This enables ultrahigh resolutions without gaps in the OTF support, and thus a fully deterministic imaging scheme. We present simulations that include shot and external noise and demonstrate the resolution power under realistic photon budgets. The technique has potential in light microscopy where low-intensity illumination is paramount while aiming for high spatial but moderate temporal resolutions.

Management of sepsis in neutropenic cancer patients: 2018 guidelines from the Infectious Diseases Working Party (AGIHO) and Intensive Care Working Party (iCHOP) of the German Society of Hematology and Medical Oncology (DGHO)

Sepsis and septic shock are major causes of mortality during chemotherapy-induced neutropenia for malignancies requiring urgent treatment. Thus, awareness of the presenting characteristics and prompt management is most important. Improved management of sepsis during neutropenia may reduce the mortality of cancer therapies. However, optimal management may differ between neutropenic and non-neutropenic patients. The aim of the current guideline is to give evidence-based recommendations for hematologists, oncologists, and intensive care physicians on how to manage adult patients with neutropenia and sepsis.

Analysis of super-resolution via 3D structured illumination intensity correlation microscopy

Intensity correlation microscopy (ICM), which is prominently known through antibunching microscopy or super-resolution optical fluctuation imaging (SOFI), provides super-resolution through a correlation analysis of antibunching of independent quantum emitters or temporal fluctuations of blinking fluorophores. For correlation order m the PSF in the signal is effectively taken to the mth power, and is thus directly shrunk by the factor m. Combined with deconvolution, a close to linear resolution improvement of factor m can be obtained. Yet, analysis of high correlation orders is challenging, which limits the achievable resolutions. Here we propose to use three dimensional structured illumination along with mth-order correlation analysis to obtain an enhanced scaling of up to m + m = 2m. Including the stokes shift or plasmonic sub-wavelength illumination enhancements beyond 2m can be achieved. Hence, resolutions far below the diffraction limit in full 3D imaging and with already low correlation orders, can potentially be achieved. Since ICM operates in the linear regime our approach may be particularly promising for enhancing the resolution in biological imaging at low illumination levels.

Incoherent Diffractive Imaging via Intensity Correlations of Hard X Rays

Established x-ray diffraction methods allow for high-resolution structure determination of crystals, crystallized protein structures, or even single molecules. While these techniques rely on coherent scattering, incoherent processes like fluorescence emission-often the predominant scattering mechanism-are generally considered detrimental for imaging applications. Here, we show that intensity correlations of incoherently scattered x-ray radiation can be used to image the full 3D arrangement of the scattering atoms with significantly higher resolution compared to conventional coherent diffraction imaging and crystallography, including additional three-dimensional information in Fourier space for a single sample orientation. We present a number of properties of incoherent diffractive imaging that are conceptually superior to those of coherent methods.

Superresolving Imaging of Arbitrary One-Dimensional Arrays of Thermal Light Sources Using Multiphoton Interference

We propose to use multiphoton interferences of photons emitted from statistically independent thermal light sources in combination with linear optical detection techniques to reconstruct, i.e., image, arbitrary source geometries in one dimension with subclassical resolution. The scheme is an extension of earlier work [S. Oppel et al., Phys. Rev. Lett. 109, 233603 (2012)], where N regularly spaced sources in one dimension were imaged by use of the Nth-order intensity correlation function. Here, we generalize the scheme to reconstruct any number of independent thermal light sources at arbitrary separations in one dimension, exploiting intensity correlation functions of order m≥3. We present experimental results confirming the imaging protocol and provide a rigorous mathematical proof for the obtained subclassical resolution.

Genetic differentiation across North America in the generalist moth Heliothis virescens and the specialist H. subflexa

The two moth species Heliothis virescens (Hv) and H. subflexa (Hs) are closely related, but have vastly different feeding habits. Hv is a generalist and an important pest in many crops in the USA, while Hs is a specialist feeding only on plants in the genus Physalis. In this study, we conducted a comparative population genetic analysis to assess whether and how generalist and specialist life styles are reflected in differences in population structures. In Hv 98% of the total variation occurred within populations. The overall differentiation (F(ST) ) between regions was 0.006 and even lower between years (0.0039) and hosts (0.0028). Analyses of population structure suggest that all individuals form one genetically homogeneous population, except for at most 12 individuals (6%) that diverged from this cluster. Population homogeneity likely results from the high mobility of Hv and its generalist feeding behaviour. Hs exhibited substantially more population structure. Even though 96% of the total variation was attributable to within-population variability, F(ST) -values between Hs populations were 10 times higher than between Hv populations. Hs populations showed significant isolation by distance. Analyses of Hs population structure suggest at least two subpopulations and thus some degree of metapopulation structure. We speculate that the patchy distribution of Physalis- the exclusive food source of Hs - contributes to differences in population structure between these closely related species. The finding that the specialist shows more population differentiation than the generalist corroborates the notion that host specialization is not an evolutionary dead end but a dynamic trait.

Evidence-based review of the literature on intrathecal delivery of pain medication

Evidence-based medicine depends on the existence of controlled clinical trials that establish the safety and efficacy of specific therapeutic techniques. Many interventions in clinical practice have achieved widespread acceptance despite little evidence to support them in the scientific literature; the critical appraisal of these interventions based on accumulating experience is a goal of medicine. To clarify the current state of knowledge concerning the use of various drugs for intraspinal infusion in pain management, an expert panel conducted a thorough review of the published literature. The exhaustive review included 5 different groups of compounds, with morphine and bupivacaine yielding the most citations in the literature. The need for additional large published controlled studies was highlighted by this review, especially for promising agents that have been shown to be safe and efficacious in recent clinical studies.

Clinical guidelines for intraspinal infusion: report of an expert panel. PolyAnalgesic Consensus Conference 2000

Consensus guidelines developed by an expert panel are helpful to clinicians when there is variation in practice and lack of a firm evidence base for an intervention, such as intraspinal therapy for pain. An internet-based survey of practitioners revealed remarkable variation in practice patterns surrounding intraspinal therapy. This prompted an interdisciplinary panel with extensive clinical experience in intraspinal infusion therapy to evaluate the results of the survey, the systematic reviews of the literature pertaining to this approach, and their own clinical experience with long-term spinal infusions. The panel proposed a scheme for the selection of drugs and doses for intraspinal therapy, and suggested guidelines for administration that would increase the likelihood of a successful outcome. These expert panel guidelines were designed to provide an initial structure for clinical decision making that is based on the best available evidence and the perspectives of experienced clinicians.

Dietary fibre: the effectiveness of a high bran intake in reducing renal calcium excretion

Fifteen healthy women were given a standardized calcium-rich diet (1800 mg calcium/day) with or without 36 g bran for 5 days. A similar study was also carried out with rice, soy and wheat bran. Urine samples were also collected 24 h. With all brans renal calcium excretion decreased and renal oxalic acid excretion increased. However, influence of rice bran was statistically significant. After 5 days of consuming 36 g rice bran/day 14 of 15 subjects showed decreased calcium excretion, but increased oxalic acid excretion. Relative supersaturation with calcium oxalate, as a measure for the risk of calcium stone formation, increased after addition of all brans.

Simultaneous determination of urinary phosphate and sulphate by ion-chromatography

An ion-chromatographic system was used for the simultaneous determination of urinary phosphate and sulphate. This method was compared with conventional methods (colorimetric, turbidimetric) with regard to practicability and reliability. All methods showed good precision and accuracy. The comparative analysis of phosphate in 80 samples revealed that both methods lead to identical results. However, in case of sulphate a significant difference of about 8% was found between the two methods. Overestimation of the analyte concentration by the turbidimetric method might be responsible for this difference. From the point of view of economy, routine analysis of urinary phosphate and sulphate by ion-chromatography is acceptable only if automated systems are used.

Experimental investigations on dissolution of incrustations on the surface of catheters

On the basis of a standardized in vitro irrigation model, the incrustation behavior of catheters was investigated using collected urine with controlled contamination (Proteus, mirabilis). Irrigation treatment with a NaCl solution did not effectively reduce incrustation compared to the control experiment. On the other hand, incrustations were definitively prevented or existing crystal deposits were largely dissolved with a citrate solution of pH 4.0 (Suby G). Analytical investigations (infrared spectroscopy, scanning electron microscopy) of the deposits on the catheter revealed the presence of struvite (MgNH4PO4 x 6H2O), brushite (CaHPO4 x 2H2O) and carbonate apatite (Ca10[PO4] [CO3OH]6[OH]2).

2,8-Dihydroxyadeninuria: laboratory diagnosis and therapy control

This report is concerned with the experience gained with two 2,8-dihydroxyadenine (2,8-DHA) stone patients. When adenine phosphoribosyltransferase (APRT) deficiency is suspected, the risk of stone formation can be detected at an early stage from the crystalline urinary sediment. Infrared spectroscopic analysis of the crystals or of a urinary stone, if present, will confirm the diagnosis. Determination of the APRT activity will facilitate quantification of the enzyme deficiency and elucidation of the hereditary history. 2,8-DHA excretion in the 24-hour urine and its circadian rhythm were determined at 3-hour intervals using a new method of high performance liquid chromatography determination. This method also provides a means of monitoring the effectiveness of allopurinol therapy.

Measurement of urinary oxalate: an enzymatic and an ion chromatographic method compared

An ion chromatographic and an enzymatic method for determination of oxalic acid in urine were compared on the basis of reliability and practicability. Both methods displayed a within-run imprecision of under 5% and a total imprecision of under 10%. The mean recovery of 0.2 mmol/l sodium oxalate lay close to 100% for both methods. After 80 parallel determinations, both methods produced statistically identical results. In terms of cost per analysis, ion chromatography is the method currently preferred when large numbers of samples are involved. If only a few samples are to be analysed the enzymatic method--without any loss of reliability--can be employed.

Dependence of urine composition on the age and sex of healthy subjects

The lithogenic and inhibitory substances in the 24-h urine of 150 healthy females and 150 healthy males were recorded. These two groups were further subdivided into 6 different age-groups, with 25 in each group. The 24-h excretion in these various age-groups displayed considerable differences in some cases, particularly in the case of the pH value, and the Ca, Mg, citrate and phosphate excretion of the women, and the Ca, Mg, uric acid, Na and K excretion of the men. All the parameters measured with respect to the males displayed higher levels of excretion than those of the females.

An evaluation of test sticks used for the measurement of the specific gravity of urine from patients with stone disease

A test stick for the measurement of the SG of the urine of stoneformers was examined. In 230 spontaneously voided urines and 45 25 h-urines the SG was measured by the test stick and compared with urinometer measurements. The two methods showed a good correlation (r = 0.86). Due to the principle of reaction of the SG-teststick a direct relationship of the SG-values to the sodium concentration and to the ionic strength of urine was found. There is no correlation between the relative supersaturation of CaOx and the SG-determination (urinometer, test stick). The handling of the SG-test stick is simple and can be easily performed by the patient.