From mild to gangrenous cholecystitis, laparoscopic cholecystectomy is safe 24 hours a day.

OBJECTIVES: Laparoscopic cholecystectomy (LC) at night remains controversial. Prior studies have not controlled for disease severity. We analyzed outcomes of LC performed day vs. night while controlling for the Parkland Grading Scale for Cholecystitis (PGS). METHODS: Analysis of the AAST multicenter evaluation of cholecystitis database was performed. Exclusion criteria included non-operative cases, open operations, and missing PGS. Cases were divided based on operation start time. PGS was used to control for disease severity. Outcomes included operative time, use of bailout techniques and complications. RESULTS: Of 759 procedures identified, 16% were nighttime LC. No differences in demographics, comorbidities, physiologic variables and PGS were noted. Operative time (108.6 min vs 105.6), bailout techniques (8.3% vs 7.4%) and complications (9.9% vs 11.3%) were similar between groups. CONCLUSION: Regardless of severity, laparoscopic cholecystectomy is safe 24-h a day. Operations performed at night have a similar complication profile to those performed during the day.

Setting the international research agenda for sarcoma together with patients and carers: first results of the Sarcoma Patient EuroNet (SPAEN) priority setting partnership.

BACKGROUND: Research in sarcomas has historically been the domain of scientists and clinicians attempting to understand the disease to develop effective treatments. This traditional approach of placing scientific rigor before the patient's reality is changing. This evolution is reflected in the growth of patient-centered organizations and patient advocacy groups that seek to meaningfully integrate patients into the research process. The aims of this study are to identify the unanswered questions regarding sarcomas (including gastrointestinal stromal tumors and desmoid fibromatosis) from patient, carer, and clinical perspectives and examine how patients and carers want to be involved in sarcoma research. METHODS: The Patient-Powered Research Network of Sarcoma Patients EuroNet set up a Priority Setting Partnership (PSP) in collaboration with stakeholders from the sarcoma research field. This PSP is largely based on the James Lind Alliance methodology. RESULTS: In total, 264 sarcoma patients (73%) and carers (27%) from all over the world participated in the online survey and covered the full spectrum of sarcomas. The topics mentioned were labeled in accordance with the Common Scientific Outline of the International Cancer Research Partnership and lists for potential research topics, advocacy topics, and requests for information were constructed. With regard to patient and carer involvement, 64% were very willing to be actively involved and mainly in the following areas: sharing perspectives, discussing patient-clinician interactions, and attending research meetings. CONCLUSIONS: The first results of this sarcoma PSP identified important research questions, but also important topics for patient advocacy groups and further improvement of information materials. Sarcoma patients and carers have a strong wish to be involved in multiple aspects of sarcoma research. The next phase will identify the top 10 research priorities per tumor type. These priorities will provide guidance for research that will achieve greatest value and impact.

Micro-fluorescence lifetime and spectral imaging of ytterbium doped laser materials.

We present the application of a confocal fluorescence microscope to the analysis of Yb-doped solid-state laser materials, with examples of Yb-doped crystals, photonic crystal fibers and fiber preforms made with different manufacturing processes. Beside the fluorescence lifetime image itself, a microscopic spectral fluorescence emission analysis is presented and spatially resolved emission cross sections are obtained. Doping concentration and its distributions and other laser optical parameters are measured, which help to analyze manufacturing steps. Further properties like photodarkening and saturation are addressed.

Brillouin scattering properties of lanthano-aluminosilicate optical fiber.

Utilizing measurements on a lanthano-aluminosilicate core optical fiber, the specific effects of lanthana (La2O3) on the Brillouin characteristics of silica-based oxide glass optical fibers are described. Lanthana is an interesting species to investigate since it possesses a wide transparency window covering the common fiber laser and telecom system wavelengths. As might be expected, it is found that the properties of lanthana are very similar to those of ytterbia (Yb2O3), namely, low acoustic velocity, wide Brillouin spectral width, and a negative photoelastic constant, with the latter two properties affording significant reductions to the Brillouin gain coefficient. However, lanthana possesses thermo-acoustic and strain-acoustic coefficients (acoustic velocity versus temperature or strain, TAC and SAC, respectively) with signs that are opposed to those of ytterbia. The lanthano-aluminosilicate (SAL) fiber utilized in this study is Brillouin-athermal (no dependence of the Brillouin frequency on temperature), but not atensic (is dependent upon the strain), which is believed to be, to the best of our knowledge, the first demonstration of such a glass fiber utilizing a compositional engineering approach.

Evaluating a federated medical search engine: tailoring the methodology and reporting the evaluation outcomes.

BACKGROUND: Federated medical search engines are health information systems that provide a single access point to different types of information. Their efficiency as clinical decision support tools has been demonstrated through numerous evaluations. Despite their rigor, very few of these studies report holistic evaluations of medical search engines and even fewer base their evaluations on existing evaluation frameworks. OBJECTIVES: To evaluate a federated medical search engine, MedSocket, for its potential net benefits in an established clinical setting. METHODS: This study applied the Human, Organization, and Technology (HOT-fit) evaluation framework in order to evaluate MedSocket. The hierarchical structure of the HOT-factors allowed for identification of a combination of efficiency metrics. Human fit was evaluated through user satisfaction and patterns of system use; technology fit was evaluated through the measurements of time-on-task and the accuracy of the found answers; and organization fit was evaluated from the perspective of system fit to the existing organizational structure. RESULTS: Evaluations produced mixed results and suggested several opportunities for system improvement. On average, participants were satisfied with MedSocket searches and confident in the accuracy of retrieved answers. However, MedSocket did not meet participants' expectations in terms of download speed, access to information, and relevance of the search results. These mixed results made it necessary to conclude that in the case of MedSocket, technology fit had a significant influence on the human and organization fit. Hence, improving technological capabilities of the system is critical before its net benefits can become noticeable. CONCLUSIONS: The HOT-fit evaluation framework was instrumental in tailoring the methodology for conducting a comprehensive evaluation of the search engine. Such multidimensional evaluation of the search engine resulted in recommendations for system improvement.

High-sensitivity dispersive Mach-Zehnder interferometer based on a dissimilar-doping dual-core fiber for sensing applications.

A dual-core fiber in which one of the cores is doped with germanium and the other with phosphorus is used as an in-line Mach-Zehnder dispersive interferometer. By ensuring an equal length but with different dispersion dependencies in the interferometer arms (the two cores), high-sensitivity strain and temperature sensing are achieved. Opposite sensitivities for high and low wavelength peaks were also demonstrated when strain and temperature was applied. To our knowledge this is the first time that such behavior is demonstrated using this type of in-line interferometer based on a dual-core fiber. A sensitivity of (0.102±0.002) nm/µÎµ, between 0 and 800 µÎµ and (-4.2±0.2) nm/°C between 47°C and 62°C is demonstrated.

Multiplexing of six micro-displacement suspended-core Sagnac interferometer sensors with a Raman-Erbium fiber laser.

This work experimentally demonstrates a long-range optical fiber sensing network for the multiplexing of fiber sensors based on photonic crystal fibers. Specifically, six photonic crystal fiber sensors which are based on a Sagnac interferometer that includes a suspended-core fiber have been used. These sensors offer a high sensitivity for micro-displacement measurements. The fiber sensor network presents a ladder structure and its operation mode is based on a fiber ring laser which combines Raman and Erbium doped fiber amplification. Thus, we show the first demonstration of photonic crystal fiber sensors for remote measurement applications up to 75 km.

High precision micro-displacement fiber sensor through a suspended-core Sagnac interferometer.

A sensing system for micro-displacement measurement based in a suspended-core fiber Sagnac interferometer is presented. The suspended-core fiber characterization was made through the use of an optical backscatter reflectometer, screening its multimodal and birefringent behavior. Its sensitivity to displacement measurements is shown to be due only to birefringence, being that core-cladding mode coupling is negligible. High precision (~0.45 µm) was obtained using three different measurement instruments, showing an extremely high stability and high insensitivity to temperature, demonstrating that the sensing system has the ability for low cost applications.

Non-operative management of acute cholecystitis in the elderly.

BACKGROUND: Although cholecystectomy is the standard therapy for acute cholecystitis (AC), operative morbidity in the elderly may be high owing to medical co-morbidities and decreased physiological reserve. Outcomes of AC in the elderly have not been fully defined with regard to operative and long-term non-operative management. METHODS: Patients aged 65 years or over admitted to a tertiary care centre with a diagnosis of AC between January 2000 and December 2009 were reviewed retrospectively. Patient data, operative and postoperative details were obtained. To determine cholecystectomy rates in the non-operative group, medical records were reviewed, and patients and families were interviewed. RESULTS: A total of 290 patients underwent cholecystectomy during the index admission, of whom 59 (20·3 per cent) required conversion to open operation. Fifty-eight of these patients experienced 98 complications, including acute respiratory failure (27), pneumonia (18), myocardial infarction (16) and sepsis (15). Some 185 patients had non-operative treatment, of whom 67 underwent percutaneous cholecystostomy. Forty-four patients subsequently had elective cholecystectomy, with a complication rate of 23 per cent. One hundred and twenty-six patients were discharged without a plan for cholecystectomy; the rate of recurrent AC was 4 per cent among the two-thirds of patients followed to within 15 months of death. No deaths or major complications occurred among those with recurrent AC. CONCLUSION: Despite selection of the best elderly candidates for cholecystectomy, postoperative morbidity was significant. Medical management, with interval cholecystectomy only for recurrent AC, may be appropriate in selected patients.

[Postcolostral immunoglobulin G (IgG) levels in newborn piglets using three different ELISA detection systems]. / Untersuchungen zur postkolostralen Immun-globulin-G-Versorgung neugeborener Saugferkel mittels unterschiedlicher ELISA-Nachweissysteme.

UNLABELLED: Objective of the study was to evaluate whether the Colostrum Quality Counter (CQC), a new test method for immunoglobulin G (IgG) levels in newborn piglets, is easy to handle and provides comparable results to established testing regimes. MATERIAL AND METHODS: Blood samples from 219 piglets from four different farms were tested for their IgG-concentrations using three different ELISA tests. Furthermore, double samples from 30 piglets were taken from both the anterior vena cava and from the tail to determine whether the collection site affects the results. The three tests used were the Colostrum Quality Counter (CQC; FarmulaONE, NL-Best), the internal IgG-ELISA from our laboratory (MUC) and a commercially-available IgG-ELISA (NAT; NatuTec, Frankfurt/Main, Germany). RESULTS: MUC and NAT showed a higher correlation to each other than to the CQC when referring to the individual results per single piglet. The results from the CQC were higher and the standard deviation was significantly greater. The sampling site had no significant effect on the IgG concentrations measured. CLINICAL RELEVANCE: The CQC is a straightforward and simple test, being very convenient for sampling a large number of piglets. CQC results were inhomogeneous with some unusually high IgG-concentrations. MUC and NAT provided comparable results to one another and the IgG-concentrations showed a good correlation.

Simultaneous measurement of curvature and strain using a suspended multicore fiber.

A suspended multicore fiber sensor for simultaneous measurement of curvature and strain is proposed. The spectral response shows evidences of several interferences arising from the seven cores of the fiber. Once the sensing head presents different sensitivities for curvature and strain measurements, these physical parameters can be discriminated by using the matrix method. The rms deviations are ±19 m(-1) and ±12.90 µÎµ for curvature and strain measurements, respectively.

Suspended-core fiber Sagnac combined dual-random mirror Raman fiber laser.

In the present work, a multiwavelength fiber laser based in the combination of a double-random mirror and a suspended-core Sagnac interferometer is presented. The double-random mirror acts by itself as a random laser, presenting a 30dB SNR, as result of multiple Rayleigh scattering events produced in the dispersion compensating fibers by the Raman amplification. The suspended-core fiber Sagnac interferometer provides the multi peak channeled spectrum, which can be tuned by changing the length of the fiber. The result of this combination is a stable multiwavelength peak laser with a minimum of ~25dB SNR, which is highly sensitive to polarization induced variations.

Selective targeting of the mTORC1/2 protein kinase complexes leads to antileukemic effects in vitro and in vivo.

The BCR/ABL tyrosine kinase promotes leukemogenesis through activation of several targets that include the phosphoinositide 3-kinase (PI3K). Tyrosine kinase inhibitors (TKIs), which target BCR/ABL, induce striking clinical responses. However, therapy with TKIs is associated with limitations such as drug intolerance, inability to universally eradicate the disease and emergence of BCR/ABL drug-resistant mutants. To overcome these limitations, we tested whether inhibition of the PI3K/target of rapamycin (mTOR) signaling pathway has antileukemic effect in primary hematopoietic stem cells and BA/F3 cells expressing the BCR/ABL oncoprotein. We determined that dual inhibition of PI3K/mTOR causes growth arrest and apoptosis leading to profound antileukemic effects both in vitro and in vivo. We also established that pharmacologic inhibition of the mTORC1/mTORC2 complexes is sufficient to cause these antileukemic effects. Our results support the development of inhibitors of the mTORC1/2 complexes for the therapy of leukemias that either express BCR/ABL or display deregulation of the PI3K/mTOR signaling pathway.

Three-dimensional light bullets in arrays of waveguides.

We report the first experimental observation of three-dimensional light bullets, excited by femtosecond pulses in a system featuring quasi-instantaneous cubic nonlinearity and a periodic, transversally modulated refractive index. Stringent evidence of the excitation of light bullets is based on time-gated images and spectra which perfectly match our numerical simulations. Furthermore, we reveal a novel evolution mechanism forcing the light bullets to follow varying dispersion or diffraction conditions, until they leave their existence range and decay.

Material-dependent growth of human skin bacteria on textiles investigated using challenge tests and DNA genotyping.

AIMS: To investigate the influence of different fibre materials on the colonization of textiles by skin bacteria present in human sweat. METHODS AND RESULTS: The total bacterial content of axillary sweat samples was determined using DNA quantification, and the diversity of bacteria present was investigated. Fabrics made of different fibres were then challenged with these sweat samples; the bacterial DNA was quantified, and the bacterial taxa present were determined. We found differences in the overall colonization, with polyester and polyamide showing the highest bacterial mass. Also, significant differences in the various taxa of bacteria present on the different materials were found. In general, synthetic materials showed a selective growth of bacterial taxa underrepresented in sweat. In contrast, a cellulose-based material showed only very few taxa, identically with those predominant in sweat. CONCLUSIONS: Our investigations demonstrated that besides the bacterial content of sweat itself, the type of material has a strong impact on the bacterial colonization of textiles. SIGNIFICANCE AND IMPACT OF THE STUDY: Odour generation is one of several effects resulting from an interaction of skin bacteria with textiles, and it is a common experience that there are differences in odour generation by different materials. Our investigations suggest that a selective growth of potentially odour-producing bacteria may account for this.

Development of a fast and reliable method for the assessment of microbial colonization and growth on textiles by DNA quantification.

There is a lack of relevant methods to assess the colonization of textiles by skin bacteria because present methods are mainly culture-based procedures. Therefore, the goal of this study was to develop a fast and sensitive culture-independent procedure for the quantification of microbial colonization and growth on textiles. We have established a suitable protocol to use DNA quantification as a reliable method for in vitroand in vivoinvestigations of textiles. For DNA extraction, a two-step procedure comprising treatment of the textile with a solution containing Triton X-100 and lysozyme for 1 h and a successive treatment by SDS and proteinase K for 2 h turned out to be most efficient. DNA extracted from textiles and fabrics was than quantified with the highly sensitive PicoGreen fluorescent dye. In vitrochallenge tests demonstrated a strong correlation between numbers of bacteria on textiles and amount of DNA extracted from textiles. Therefore, this method was used to compare different materials after in vivotrials for assessment of their susceptibility for microbial colonization and growth.

Model analysis on alveolar-capillary O2 equilibration during exercise.

The present article was aimed at determining the alveolar-capillary PO2 difference (deltaP(AcO2)) during exercise. The working hypothesis was that values of the pulmonary NO diffusing capacity can be used to calculate (deltaP(AcO2)) data on the basis of well-known laws of pulmonary gas exchange. For this purpose, we analysed the pertinent data of three studies performed on 35 healthy, non-athletic non-smokers of similar age at seven different exercise intensities. Calculated mean values of alveolar-capillary PO2 difference aggravated from deltaP(AcO2) at rest to (deltaP(AcO2))=18 mmHg at a performance capacity amounting to 90% of the maximum level. Regression analysis revealed (deltaP(AcO2))=0.31* (V O2/V O2 max)2 at a very high significance level (n=7, r=0.999, P<0.0000082). Due to the non-linear increase of (deltaP(AcO2)) with inclining O(2) consumption, our model analysis confirms the opinion that pulmonary diffusion decreasingly determines maximal aerobic power.

Two-dimensional high-precision fiber waveguide arrays for coherent light propagation.

Fiber waveguide arrays can be applied as a very useful tool for the investigation of effects in discrete optics. The observation of coherent propagation in such discrete waveguide arrays requires, however, high structural precision and great material homogeneity. The fabrication of such a fiber array with close tolerances compared to conventional fiber technology is discussed. Linear propagation effects are modeled for an ideal fiber waveguide array and are compared with experimental results. The good agreement of these results with each other indicates the applicability of such fiber waveguide arrays in studying linear and non-linear properties in discrete optics.

Porcine skin visible lesion thresholds for near-infrared lasers including modeling at two pulse durations and spot sizes.

With the advent of such systems as the airborne laser and advanced tactical laser, high-energy lasers that use 1315-nm wavelengths in the near-infrared band will soon present a new laser safety challenge to armed forces and civilian populations. Experiments in nonhuman primates using this wavelength have demonstrated a range of ocular injuries, including corneal, lenticular, and retinal lesions as a function of pulse duration. American National Standards Institute (ANSI) laser safety standards have traditionally been based on experimental data, and there is scant data for this wavelength. We are reporting minimum visible lesion (MVL) threshold measurements using a porcine skin model for two different pulse durations and spot sizes for this wavelength. We also compare our measurements to results from our model based on the heat transfer equation and rate process equation, together with actual temperature measurements on the skin surface using a high-speed infrared camera. Our MVL-ED50 thresholds for long pulses (350 micros) at 24-h postexposure are measured to be 99 and 83 J cm(-2) for spot sizes of 0.7 and 1.3 mm diam, respectively. Q-switched laser pulses of 50 ns have a lower threshold of 11 J cm(-2) for a 5-mm-diam top-hat laser pulse.

Highly polarization-dependent periodic coupling in mechanically induced long period grating over air-silica fibers.

A very flexible and versatile tunable mechanical grating platform is introduced, with which highly polarization-dependent mode coupling is observed for three types of air-silica microstructured fibers: hollow core fiber, hexagonal-boundary holey fiber (HHF), and circular-boundary holey fiber. The resonances of gratings showed highly polarization-dependent broadband coupling compared with conventional single-mode fibers due to their unique beat-length dispersions between the core and the cladding modes, which could find applications in wideband polarization-dependent loss compensation. We further present significance of the spatial symmetry of HHF in distinct mode coupling for different rotation angles around the fiber axis.