Identification of weak molecular absorption in single-wavelength s-SNOM images.

Scattering-type scanning near-field optical microscopy (s-SNOM) allows for nanoscale optical mapping of manifold material properties. It is based on interferometric recording of the light scattered at a scanning probe tip. For dielectric samples such as biological materials or polymers, the near-field amplitude and phase signals of the scattered field reveal the local reflectivity and absorption, respectively. Importantly, absorption in s-SNOM imaging corresponds to a positive phase contrast relative to a non-absorbing reference sample. Here, we describe that in certain conditions (weakly or non- absorbing material placed on a highly reflective substrate), a slight negative phase contrast may be observed, which can hinder the recognition of materials exhibiting a weak infrared absorption. We first document this effect and explore its origin using representative test samples. We then demonstrate straightforward simple correction methods that remove the negative phase contrast and that allow for the identification of weak absorption contrasts.

Pseudoheterodyne interferometry for multicolor near-field imaging.

We report the development and characterization of a detection technique for scattering-type scanning near-field optical microscopy (s-SNOM) that enables near-field amplitude and phase imaging at two or more wavelengths simultaneously. To this end, we introduce multispectral pseudoheterodyne (PSH) interferometry, where infrared lasers are combined to form a beam with a discrete spectrum of laser lines and a time-multiplexing scheme is employed to allow for the use of a single infrared detector. We first describe and validate the implementation of multispectral PSH into a commercial s-SNOM instrument. We then demonstrate its application for the real-time correction of the negative phase contrast (NPC), which provides reliable imaging of weak IR absorption at the nanoscale. We anticipate that multispectral PSH could improve data throughput, reduce effects of sample and interferometer drift, and help to establish multicolor s-SNOM imaging as a regular imaging modality, which could be particularly interesting as new infrared light sources become available.

Computational refocusing in phase-resolved confocal microscopy.

We demonstrate numerical refocusing in coherent confocal laser scanning microscopy based on synthetic optical holography. In this physics-based approach, computational propagation is implemented on the complex signal recovered in synthetic holography, consistent with wave physics and the parameters of the microscope. An experimental demonstration is shown to restore an in-focus image of a test object from data acquired at several focal plane off-sets. Numerical refocusing can provide focused views on samples with large height variation, with a potential application in confocal optical surface profiling.

All-digital histopathology by infrared-optical hybrid microscopy.

Optical microscopy for biomedical samples requires expertise in staining to visualize structure and composition. Midinfrared (mid-IR) spectroscopic imaging offers label-free molecular recording and virtual staining by probing fundamental vibrational modes of molecular components. This quantitative signal can be combined with machine learning to enable microscopy in diverse fields from cancer diagnoses to forensics. However, absorption of IR light by common optical imaging components makes mid-IR light incompatible with modern optical microscopy and almost all biomedical research and clinical workflows. Here we conceptualize an IR-optical hybrid (IR-OH) approach that sensitively measures molecular composition based on an optical microscope with wide-field interferometric detection of absorption-induced sample expansion. We demonstrate that IR-OH exceeds state-of-the-art IR microscopy in coverage (10-fold), spatial resolution (fourfold), and spectral consistency (by mitigating the effects of scattering). The combined impact of these advances allows full slide infrared absorption images of unstained breast tissue sections on a visible microscope platform. We further show that automated histopathologic segmentation and generation of computationally stained (stainless) images is possible, resolving morphological features in both color and spatial detail comparable to current pathology protocols but without stains or human interpretation. IR-OH is compatible with clinical and research pathology practice and could make for a cost-effective alternative to conventional stain-based protocols for stainless, all-digital pathology.

[Implementing the Objective Structured Clinical Examination (OSCE) in postgraduate education in nursing science-a pilot project to assess ethical competences in nursing practice and research]. / Implementierung des Objective Structured Clinical Examination (OSCE) im Masterstudiengang Pflegewissenschaft ­ Pilotprojekt zur Prüfung der ethischen Kompetenz in Pflegepraxis und -forschung.

Background: Teaching ethical competencies is an essential component of professional and postgraduate curricula. Developing practical-ethical problem-solving competencies as well as appraising program-specific studies and related research ethics are topics typically addressed. However, assessment of these ethical competencies poses a challenge. Written or oral assessment formats addressing relevant learning objectives is mainly limited to knowledge testing alone, often not capturing relevant skills or attitudes pertinent to those competencies. Aim: During the reaccreditation of the masters of science (MSc) program in Nursing Science at Witten/Herdecke University, this challenge was addressed by implementation of an innovative examination format for postgraduate education. Procedure: For the module "Ethics in nursing practice and research" a format based on the Objective Structured Clinical Examination (OSCE) format was developed. This assessment method incorporates evaluation of acquired skills and attitudes of nursing students. Conclusion: The article demonstrates development and adaption of the OSCE format for this purpose.

Accessible quantitative phase imaging in confocal microscopy with sinusoidal-phase synthetic optical holography.

We present a technically simple implementation of quantitative phase imaging in confocal microscopy based on synthetic optical holography with sinusoidal-phase reference waves. Using a Mirau interference objective and low-amplitude vertical sample vibration with a piezo-controlled stage, we record synthetic holograms on commercial confocal microscopes (Nikon, model: A1R; Zeiss: model: LSM-880), from which quantitative phase images are reconstructed. We demonstrate our technique by stain-free imaging of cervical (HeLa) and ovarian (ES-2) cancer cells and stem cell (mHAT9a) samples. Our technique has the potential to extend fluorescence imaging applications in confocal microscopy by providing label-free cell finding, monitoring cell morphology, as well as non-perturbing long-time observation of live cells based on quantitative phase contrast.

Transient vibration imaging with time-resolved synthetic holographic confocal microscopy.

We introduce a new modality for dynamic phase imaging in confocal microscopy based on synthetic optical holography. By temporal demultiplexing of the detector signal into a series of holograms, we record time-resolved phase images directly in the time domain at a bandwidth as determined by the photo detector and digitizer. We demonstrate our method by optical imaging of transient vibrations in an atomic force microscope cantilever with 100 ns time resolution, and observe the dynamic deformation of the cantilever surface after excitation with broadband mechanical pulses. Temporal Fourier transform of a single data set acquired in 4.2 minutes yields frequency and mode profile of all excited out-of-plane vibration modes with sub-picometer vertical sensitivity and sub-micrometer lateral resolution. Our method has the potential for transient and spectroscopic vibration imaging of micromechanical systems at nano-and picosecond scale time resolution.

Near-Field Imaging of Phased Array Metasurfaces.

Phased-antenna metasurfaces can impart abrupt, spatially dependent changes to the amplitude, phase, and polarization of light and thus mold wavefronts in a desired fashion. Here we present an experimental and computational near-field study of metasurfaces based on near-resonant V-shaped antennas and connect their near- and far-field optical responses. We show that far fields can be obtained from limited, experimentally obtained knowledge of the near fields, paving the way for experimental near-field characterization of metasurfaces and other optical nanostructures and prediction of their far fields from the near-field measurements.

Magnitude and phase-resolved infrared vibrational nanospectroscopy with a swept quantum cascade laser.

We demonstrate a method of rapidly acquiring background-free infrared near-field spectra by combining magnitude and phase resolved scattering-type scanning near-field optical microscopy (s-SNOM) with a wavelength-swept quantum cascade laser (QCL). Background-free measurement of both near-field magnitude and phase allows for direct comparison with far-field absorption spectra, making the technique particularly useful for rapid and straightforward nanoscale material identification. Our experimental setup is based on the commonly used pseudo-heterodyne detection scheme, which we modify by operating the interferometer in the white light position; we show this adjustment to be critical for measurement repeatability. As a proof-of-principle experiment we measure the near-field spectrum between 1690 and 1750 cm(-1) of a PMMA disc with a spectral resolution of 1.5 cm(-1). We finish by chemically identifying two fibers on a sample surface by gathering their spectra between 1570 and 1750 cm(-1), each with a measurement time of less than 2.5 minutes. Our method offers the possibility of performing both nanoscale-resolved point spectroscopy and monochromatic imaging with a single laser that is capable of wavelength-sweeping.

Synthetic optical holography with nonlinear-phase reference.

Synthetic optical holography (SOH) provides efficient encoding of the complex optical signal, both amplitude and phase, for scanning imaging methods. Prior demonstrations have synthesized reference fields with a plane-wave-like linear variation of the phase with position. To record large images without probe-mirror synchronization, a long-travel, closed-loop reference mirror stage has been required. Here we present SOH with a synthetic reference wave with sinusoidal spatial variation of the phase. This allows the use of open loop, limited mirror travel range in SOH, and leads to a novel holographic inversion algorithm. We validate the theory with scans of graphene grain boundaries from a scanning near-field optical microscope, for which SOH has been shown to drastically increase scan speeds [Nat. Commun. 5, 3499 (2014)].

Resonant antenna probes for tip-enhanced infrared near-field microscopy.

We report the development of infrared-resonant antenna probes for tip-enhanced optical microscopy. We employ focused-ion-beam machining to fabricate high-aspect ratio gold cones, which replace the standard tip of a commercial Si-based atomic force microscopy cantilever. Calculations show large field enhancements at the tip apex due to geometrical antenna resonances in the cones, which can be precisely tuned throughout a broad spectral range from visible to terahertz frequencies by adjusting the cone length. Spectroscopic analysis of these probes by electron energy loss spectroscopy, Fourier transform infrared spectroscopy, and Fourier transform infrared near-field spectroscopy corroborates their functionality as resonant antennas and verifies the broad tunability. By employing the novel probes in a scattering-type near-field microscope and imaging a single tobacco mosaic virus (TMV), we experimentally demonstrate high-performance mid-infrared nanoimaging of molecular absorption. Our probes offer excellent perspectives for optical nanoimaging and nanospectroscopy, pushing the detection and resolution limits in many applications, including nanoscale infrared mapping of organic, molecular, and biological materials, nanocomposites, or nanodevices.

Experimental verification of field-enhanced molecular vibrational scattering at single infrared antennas.

Surface-enhanced infrared absorption (SEIRA) spectroscopy exploits the field enhancement near nanophotonic structures for highly sensitive characterization of (bio)molecules. The vibrational signature observed in SEIRA spectra is typically interpreted as field-enhanced molecular absorption. Here, we study molecular vibrations in the near field of single antennas and show that the vibrational signature can be equally well explained by field-enhanced molecular scattering. Although the infrared scattering cross section of molecules is negligible compared to their absorption cross section, the interference between the molecular-scattered field and the incident field enhances the spectral signature caused by molecular vibrational scattering by 10 orders of magnitude, thus becoming as large as that of field-enhanced molecular absorption. We provide experimental evidence that field-enhanced molecular scattering can be measured, scales in intensity with the fourth power of the local field enhancement and fully explains the vibrational signature in SEIRA spectra in both magnitude and line shape. Our work may open new paths for developing highly sensitive SEIRA sensors that exploit the presented scattering concept.

Evaluating an evidence-based curriculum in undergraduate palliative care education: piloting a phase II exploratory trial for a complex intervention.

BACKGROUND: By 2013 Palliative Care will become a mandatory examination subject in the medical curriculum in Germany. There is a pressing need for effective and well-designed curricula and assessment methods. Debates are on going as how Undergraduate Palliative Care Education (UPCE) should be taught and how knowledge and skills should be assessed. It is evident by this time that the development process of early curricula in the US and UK has led to a plethora of diverse curricula which seem to be partly ineffective in improving the care for the seriously ill and dying offered by newly qualified doctors, as is demonstrated in controlled evaluations. The goals of this study were to demonstrate an evidence-based approach towards developing UPCE curricula and investigate the change in medical students' self-perceived readiness to deal with palliative care patients and their families. METHODS: To evaluate the effects of the UPCE curriculum we chose a prospective, controlled, quasi-experimental, pre, retrospective-pre, post study design. A total of n = 37 3rd and 4th -year medical students were assigned to the intervention group (n = 15; 4th -year) and to the control group (n = 22; 3rd-year). Resting on the self-efficacy concept of Bandura the measurement was conducted by a refined test-battery based on two independent measurements (the revised Collet-Lester-Fear-of-Death-Scale and the instrument of the "Program in Palliative Care Education and Practice" at Harvard Medical School) including 68 items altogether in a five-point Likert-scale. These items were designed to test elementary skills in caring for the dying and their relatives as perceived by medical undergraduates. Datasets from both groups were analysed by paired and independent two-sample t-test. The TREND statement for reporting non-randomized evaluations was applied for reporting on this quasi-experimental study. RESULTS: Three constructs showed statistically significant differences comparing the intervention group before and after. Willingness to accompany a dying patient increased from 21.40 to 37.30 (p < .001). Self-estimation of competence in communication with dying patients and their relatives increased from 12.00 to 23.60 (p = .001). Finally, self-estimation of knowledge and skills in Palliative Care increased from 8.30 to 13.20 (p = .001). CONCLUSIONS: This study is a small but systematic step towards rigorous curricular development in palliative care. Our manualised curriculum is available for scrutiny and scientific feedback to support an open and constructive process of best-practice comparison in palliative care.

Real-space mapping of Fano interference in plasmonic metamolecules.

An unprecedented control of the spectral response of plasmonic nanoantennas has recently been achieved by designing structures that exhibit Fano resonances. This new insight is paving the way for a variety of applications, such as biochemical sensing and surface-enhanced Raman spectroscopy. Here we use scattering-type near-field optical microscopy to map the spatial field distribution of Fano modes in infrared plasmonic systems. We observe in real space the interference of narrow (dark) and broad (bright) plasmonic resonances, yielding intensity and phase toggling between different portions of the plasmonic metamolecules when either their geometric sizes or the illumination wavelength is varied.

[Nurses end-of-life decision making. Professional nurses about the application of complementary care for patients with breathlessness]. / Pflegerische Entscheidungen am Lebensende. Professionell Pflegende zum Einsatz komplementärpflegerischer Massnahmen bei Patienten mit Atemnot.

Aim of this study was to explore the nursing professionals' experiences and handling of decisions to provide complementary care for patients with breathlessness at the end of life. Therefore, it presents one of the first studies in the German speaking area addressing genuine nursing decisions belonging to their responsibility. Based on Grounded Theory Methodology the data were collected and analysed synchronously. Results show a high professional and emphatic decision making process always focussing on the patient. "To consider the patient" emanates from their general attitude and is influenced by the possibility to be human themselves and by reflecting ones limitations. At the same time participants described a repertoire of complementary care procedures which they use in their daily nursing routine. This study illustrates the decision making process and outlines the general attitude influencing all decisions and actions of nurses to relieve breathlessness. Furthermore, it shows for the first time a range of currently used complementary care procedures to treat patients with breathlessness at the end of life.

Real-space nanoimaging of THz polaritons in the topological insulator Bi2Se3.

Plasmon polaritons in topological insulators attract attention from a fundamental perspective and for potential THz photonic applications. Although polaritons have been observed by THz far-field spectroscopy on topological insulator microstructures, real-space imaging of propagating THz polaritons has been elusive so far. Here, we show spectroscopic THz near-field images of thin Bi2Se3 layers (prototypical topological insulators) revealing polaritons with up to 12 times increased momenta as compared to photons of the same energy and decay times of about 0.48 ps, yet short propagation lengths. From the images we determine and analyze the polariton dispersion, showing that the polaritons can be explained by the coupling of THz radiation to various combinations of Dirac and massive carriers at the Bi2Se3 surfaces, massive bulk carriers and optical phonons. Our work provides critical insights into the nature of THz polaritons in topological insulators and establishes instrumentation and methodology for imaging of THz polaritons.

Total Splenectomy for a Giant Isolated Splenic Hydatid Cyst Compressing the Abdominal Viscera: A Case Report.

BACKGROUND Extrahepatic and extrapulmonary localizations of cystic echinococcosis (CE) are rare and the incidence of splenic involvement is seen in 1.0% to 3.3% of all cases in the endemic areas of the Middle East and Asia. The diagnostic pathway consists of a detailed travel history, physical examination, abdominal ultrasonography, computed tomography, and serological tests. The efficacy of perioperative administration of albendazole (400 mg twice a day) has been proven; however, the appropriate surgical procedure for the treatment of giant, centrally located splenic hydatid cysts remains controversial. CASE REPORT We present the case of a 49-year-old woman referred to our hospital for a suspected isolated splenic hydatid cyst causing a compression of the right kidney, stomach, and the tail of the pancreas. She reported chronic pain in the left upper quadrant and a history of contact with animals. She underwent open splenectomy via a medial to lateral approach to minimize manipulation of the spleen. In addition, she received perioperative parasitostatic drug therapy with albendazole. The postoperative period was uneventful and the histologic analysis confirmed the diagnosis. CONCLUSIONS The spleen is a rare location for isolated CE, especially in non-endemic areas and must be considered in the differential diagnosis of splenic cystic masses. Surgical resection remains the most effective treatment that completely resolves this condition. A comparison of randomized trials is needed to compare the recurrence rates between splenectomy and spleen-preserving procedures in the treatment of giant splenic hydatid cysts.

Palliative care for the elderly--developing a curriculum for nursing and medical students.

BACKGROUND: Delivering palliative care to elderly, dying patients is a present and future challenge. In Germany, this has been underlined by a 2009 legislation implementing palliative care as compulsory in the medical curriculum. While the number of elderly patients is increasing in many western countries multimorbidity, dementia and frailty complicate care. Teaching palliative care of the elderly to an interprofessional group of medical and nursing students can help to provide better care as acknowledged by the ministry of health and its expert panels. In this study we researched and created an interdisciplinary curriculum focussing on the palliative care needs of the elderly which will be presented in this paper. METHODS: In order to identify relevant learning goals and objectives for the curriculum, we proceeded in four subsequent stages. We searched international literature for existing undergraduate palliative care curricula focussing on the palliative care situation of elderly patients; we searched international literature for palliative care needs of the elderly. The searches were sensitive and limited in nature. Mesh terms were used where applicable. We then presented the results to a group of geriatrics and palliative care experts for critical appraisal. Finally, the findings were transformed into a curriculum, focussing on learning goals, using the literature found. RESULTS: The literature searches and expert feedback produced a primary body of results. The following deduction domains emerged: Geriatrics, Palliative Care, Communication & Patient Autonomy and Organisation & Social Networks. Based on these domains we developed our curriculum. CONCLUSIONS: The curriculum was successfully implemented following the Kern approach for medical curricula. The process is documented in this paper. The information given may support curriculum developers in their search for learning goals and objectives.

[Cura sui--selfcare and its relationship to nursing]. / CURA SUI - Die Selbstsorge und ihre Beziehung zur Pflege.

Self care is an answer to the response of finiteness, which is given through the fact of the human body. The article demonstrates in reference to the Selfcaredeficit-Theory (Orem, 2006) how self care in everyday life, ancient roman called it cura sui, is related to nursing practice, specially to acutecare. Self care turns out as an category of ambivalence between ethics and power.

A Rare Case of a Left-sided Gallbladder Accompanied with an Aplastic Cystic Duct in a Patient with Acute Cholecystitis.

BACKGROUND A left-sided gallbladder without situs inversus is a rare congenital anomaly of the gallbladder with a prevalence ranging from 0.04-0.3%. CASE REPORT We present a case of a female patient, referred to our clinic with clinical features of an acute cholecystitis. After performing the standard preoperative investigations, which confirmed the diagnosis, the patient underwent a laparoscopic cholecystectomy. We found a left-sided gallbladder, attached to the lower surface of the left lobe of the liver. During the dissection in the Callot triangle an aplastic cystic duct was also identified. The extirpation of the gallbladder was performed anterograde, allowing a better exposition of the critical structures. CONCLUSIONS A left sided gallbladder is almost an incidental finding, which can be accompanied with further anomalies of the biliary tree. A combination of these 2 variations is very rare without any other reported cases in the literature.