The integration of 1.5 T MRI functionality with a radiotherapy linear accelerator (linac) has been pursued since 1999 by the UMC Utrecht in close collaboration with Elekta and Philips. The idea ...behind this integrated device is to offer unrivalled, online and real-time, soft-tissue visualization of the tumour and the surroundings for more precise radiation delivery. The proof of concept of this device was given in 2009 by demonstrating simultaneous irradiation and MR imaging on phantoms, since then the device has been further developed and commercialized by Elekta. The aim of this work is to demonstrate the clinical feasibility of online, high-precision, high-field MRI guidance of radiotherapy using the first clinical prototype MRI-Linac. Four patients with lumbar spine bone metastases were treated with a 3 or 5 beam step-and-shoot IMRT plan. The IMRT plan was created while the patient was on the treatment table and based on the online 1.5 T MR images; pre-treatment CT was deformably registered to the online MRI to obtain Hounsfield values. Bone metastases were chosen as the first site as these tumors can be clearly visualized on MRI and the surrounding spine bone can be detected on the integrated portal imager. This way the portal images served as an independent verification of the MRI based guidance to quantify the geometric precision of radiation delivery. Dosimetric accuracy was assessed post-treatment from phantom measurements with an ionization chamber and film. Absolute doses were found to be highly accurate, with deviations ranging from 0.0% to 1.7% in the isocenter. The geometrical, MRI based targeting as confirmed using portal images was better than 0.5 mm, ranging from 0.2 mm to 0.4 mm. In conclusion, high precision, high-field, 1.5 T MRI guided radiotherapy is clinically feasible.
The Soot Particle Aerosol Mass Spectrometer (SP-AMS) was developed to measure the chemical and physical properties of particles containing refractory black carbon (rBC). The SP-AMS is an Aerodyne ...Aerosol Mass Spectrometer (AMS) equipped with an intracavity laser vaporizer (1064 nm) based on the Single Particle Soot Photometer (SP2) design, in addition to the resistively heated, tungsten vaporizer used in a standard AMS. The SP-AMS can be operated with the laser vaporizer alone, with both the laser and tungsten vaporizers, or with the tungsten vaporizer alone. When operating with only the laser vaporizer, the SP-AMS is selectively sensitive to laser-light absorbing particles, such as ambient rBC-containing particles as well as metal nanoparticles, and measures both the refractory and nonrefractory components. When operated with both vaporizers and modulating the laser on and off, the instrument measures the refractory components of absorbing particles and the nonrefractory particulate matter of all sampled particles. The SP-AMS design, mass spectral interpretation, calibration, and sensitivity are described. Instrument calibrations yield a sensitivity of greater than 140 carbon ions detected per picogram of rBC mass sampled, a 3σ detection limit of less than 0.1 μg·m
−3
for 60 s averaging, and a mass-specific ionization efficiency relative to particulate nitrate of 0.2 ± 0.1. Sensitivities were found to vary depending upon laser-particle beam overlap. The utility of the instrument to characterize ambient rBC aerosol is demonstrated.
Copyright 2012 American Association for Aerosol Research
A single-particle soot photometer (SP2) was flown on a NASA WB-57F high-altitude research aircraft in November 2004 from Houston, Texas. The SP2 uses laser-induced incandescence to detect individual ...black carbon (BC) particles in an air sample in the mass range of approx.3-300 fg (approx.0.15-0.7 microns volume equivalent diameter). Scattered light is used to size the remaining non-BC aerosols in the range of approx.0.17-0.7 microns diameter. We present profiles of both aerosol types from the boundary layer to the lower stratosphere from two midlatitude flights. Results for total aerosol amounts in the size range detected by the SP2 are in good agreement with typical particle spectrometer measurements in the same region. All ambient incandescing particles were identified as BC because their incandescence properties matched those of laboratory-generated BC aerosol. Approximately 40% of these BC particles showed evidence of internal mixing (e.g., coating). Throughout profiles between 5 and 18.7 km, BC particles were less than a few percent of total aerosol number, and black carbon aerosol (BCA) mass mixing ratio showed a constant gradient with altitude above 5 km. SP2 data was compared to results from the ECHAM4/MADE and LmDzT-INCA global aerosol models. The comparison will help resolve the important systematic differences in model aerosol processes that determine BCA loadings. Further intercomparisons of models and measurements as presented here will improve the accuracy of the radiative forcing contribution from BCA.
A series of ruthenium(II) bis(2,2'-bipyridyl) complexes containing N-phenyl-substituted diazafluorenes (Ru-C1, Ru-C6, Ru-C7 and Ru-F) was synthesized and their potential antibacterial activity ...against methicillin resistant Staphylococcus aureus (MRSA) was investigated. The Ru-C7 complex showed significant improvement in both minimum inhibitory concentration (MIC, 6.25 μg mL(-1)) and minimum bactericidal concentration (MBC, 25 μg mL(-1)) towards MRSA when compared with those of methicillin (positive control) (MIC = 25 μg mL(-1) and MBC = 100 μg mL(-1)). The Ru-C7 complex possessed much stronger antibacterial effects than the Ru-C6 complex (MIC, 25 μg mL(-1), MBC, >100 μg mL(-1)). Both Ru-C6 and Ru-C7 complexes were also demonstrated to be biologically safe when tested on normal human skin keratinocytes.
In colorectal cancer surgery there is a delicate balance between complete removal of the tumor and sparing as much healthy tissue as possible. Especially in rectal cancer, intraoperative tissue ...recognition could be of great benefit in preventing positive resection margins and sparing as much healthy tissue as possible. To better guide the surgeon, we evaluated the accuracy of diffuse reflectance spectroscopy (DRS) for tissue characterization during colorectal cancer surgery and determined the added value of DRS when compared to clinical judgement.
DRS spectra were obtained from fat, healthy colorectal wall and tumor tissue during colorectal cancer surgery and results were compared to histopathology examination of the measurement locations. All spectra were first normalized at 800 nm, thereafter two support vector machines (SVM) were trained using a tenfold cross-validation. With the first SVM fat was separated from healthy colorectal wall and tumor tissue, the second SVM distinguished healthy colorectal wall from tumor tissue.
Patients were included based on preoperative imaging, indicating advanced local stage colorectal cancer. Based on the measurement results of 32 patients, the classification resulted in a mean accuracy for fat, healthy colorectal wall and tumor of 0.92, 0.89 and 0.95 respectively. If the classification threshold was adjusted such that no false negatives were allowed, the percentage of false positive measurement locations by DRS was 25% compared to 69% by clinical judgement.
This study shows the potential of DRS for the use of tissue classification during colorectal cancer surgery. Especially the low false positive rate obtained for a false negative rate of zero shows the added value for the surgeons. Trail registration This trail was performed under approval from the internal review board committee (Dutch Trail Register NTR5315), registered on 04/13/2015, https://www.trialregister.nl/trial/5175 .
Background
The optimal treatment sequence for patients with rectal cancer and synchronous liver metastases remains unclear. The aim of this study was to evaluate the feasibility and effectiveness of ...short‐course pelvic radiotherapy (5 × 5 Gy) followed by systemic therapy and local treatment of all tumour sites in patients with potentially curable stage IV rectal cancer in daily practice.
Methods
This was a retrospective study performed in eight tertiary referral centres in the Netherlands. Patients aged 18 years or above with rectal cancer and potentially resectable liver ± extrahepatic metastases, treated between 2010 and 2015, were eligible. Main outcomes included full completion of treatment schedule, symptom control and survival.
Results
In total, 169 patients were included with a median follow‐up of 49·5 (95 pr cent c.i. 43·6 to 55·6) months. The completion rate for the entire treatment schedule was 65·7 per cent. Three‐year progression‐free survival and overall survival (OS) rates were 24·2 (95 per cent c.i. 16·6 to 31·6) and 48·8 (40·4 to 57·2) per cent respectively. Median OS of patients who responded well and completed the treatment schedule was 51·5 months, compared with 15·1 months for patients who did not complete the treatment (P < 0·001). Adequate symptom control of the primary tumour was achieved in 87·0 per cent of all patients.
Conclusion
Multimodal treatment leads to relief of symptoms in most patients, and is associated with good survival rates in those able to complete the schedule. Correction added on 12 February 2020, after first online publication: the Conclusion has been reworded for clarity
Antecedentes
La secuencia óptima de tratamiento en pacientes con cáncer de recto y metástasis hepáticas sincrónicas sigue sin estar clara. El objetivo de este estudio fue evaluar en la práctica diaria la viabilidad y efectividad de la radioterapia pélvica de ciclo corto (5 x 5 Gy) seguida de tratamiento sistémico y tratamiento local de todas las localizaciones del tumor primario en pacientes con cáncer de recto estadio IV potencialmente curables.
Métodos
Estudio retrospectivo realizado en ocho centros terciarios de referencia en Holanda. Se consideró elegibles a los pacientes mayores de 18 años con cáncer de recto y metástasis hepáticas ± extrahepáticas potencialmente resecables, que fueron tratados entre 2010 y 2015. Los criterios de valoración principales incluyeron la finalización completa del programa de tratamiento, el control de los síntomas y la supervivencia.
Resultados
En total se incluyeron 169 pacientes con una mediana de seguimiento de 50 meses (rango 2‐89 meses). La tasa de finalización del programa de tratamiento completo fue del 65,7%. Las tasas de supervivencia libre de progresión a 3 años y supervivencia global (overall survival, OS) fueron 24,2% (i.c. del 95% 16,6‐31,6) y 48,8% (i.c. del 95% 40,4‐57,2), respectivamente. La mediana de OS de los pacientes que respondieron bien y completaron el programa de tratamiento fue de 51,5 meses, en comparación con 15,1 meses en pacientes que no completaron el tratamiento (P < 0,001). Se logró un control adecuado de los síntomas del tumor primario en el 87,0% de todos los pacientes.
Conclusión
El tratamiento multimodal consigue paliar los síntomas en la mayoría de los pacientes y se asocia con buenas tasas de supervivencia en aquellos pacientes que pueden completar el programa.
Treatment of patients with potentially curable stage IV rectal cancer with short‐course pelvic radiotherapy followed by systemic therapy and local treatment of all tumour sites is a feasible and effective schedule. Long‐term survival was accomplished in one‐third of patients, while providing adequate symptom relief in the majority of the other patients.
Good results
Biomass burning represents a major global source of aerosols impacting direct radiative forcing and cloud properties. Thus, the goal of a number of current studies involves developing a better ...understanding of how the chemical composition and mixing state of biomass burning aerosols evolve during atmospheric aging processes. During the Ice in Clouds Experiment-Layer Clouds (ICE-L) in the fall of 2007, smoke plumes from two small Wyoming Bureau of Land Management prescribed burns were measured by on-line aerosol instrumentation aboard a C-130 aircraft, providing a detailed chemical characterization of the particles. After ~2–4 min of aging, submicron smoke particles, produced primarily from sagebrush combustion, consisted predominantly of organics by mass, but were comprised primarily of internal mixtures of organic carbon, elemental carbon, potassium chloride, and potassium sulfate. Significantly, the fresh biomass burning particles contained minor mass fractions of nitrate and sulfate, suggesting that hygroscopic material is incorporated very near or at the point of emission. The mass fractions of ammonium, sulfate, and nitrate increased with aging up to ~81–88 min and resulted in acidic particles. Decreasing black carbon mass concentrations occurred due to dilution of the plume. Increases in the fraction of oxygenated organic carbon and the presence of dicarboxylic acids, in particular, were observed with aging. Cloud condensation nuclei measurements suggested all particles >100 nm were active at 0.5% water supersaturation in the smoke plumes, confirming the relatively high hygroscopicity of the freshly emitted particles. For immersion/condensation freezing, ice nuclei measurements at −32 °C suggested activation of ~0.03–0.07% of the particles with diameters greater than 500 nm.
Existing sex education programmes have failed in involving people with intellectual disabilities in the development of these programmes. Not involving the target population decreases the likelihood ...that the sex education programme will be effective. This study was conducted to assess the perspectives of people with intellectual disabilities on several sexuality-related topics. Semi-structured interviews were held with 20 people with intellectual disabilities covering topics such as: sex education, relationships, sex, social media, parenthood and support. The reported frequency of sex education the participants receive is low. Their knowledge regarding sex education is mainly limited to topics such as safe sex, contraception and STI’s and tends to be superficial. Additionally, knowledge on safe sex does not always translate to safe sex behaviour. Finally, relationships are important for most participants; mainly because they don’t want to be alone. Findings from both this study and literature shows that there seems to be a need for high quality sex education. Topics to consider to include are: online relationships, social media and parenthood. It would also be beneficial to focus on sexuality-related skills. Finally, to increase the effectiveness of a sex education programme, it is advisable that a theory-and evidence-based framework, such as Intervention Mapping, is used for its development.
A single particle soot photometer (SP2) was operated on the NCAR C-130 during the MIRAGE campaign (part of MILAGRO), sampling black carbon (BC) over Mexico. The highest BC concentrations were ...measured over Mexico City (sometimes as much as 2 μg/m3) and over hill-fires to the south of the city. The age of plumes outside of Mexico City was determined using a combination of HYSPLIT trajectories, WRF-FLEXPART modeling and CMET balloon tracks. As expected, older, diluted air masses had lower BC concentrations. A comparison of carbon monoxide (CO) and BC suggests a CO background of around 65 ppbv, and a background-corrected BC/COnet ratio of 2.89±0.89 (ng/m3-STP)/ppbv (average ± standard deviation). This ratio is similar for fresh emissions over Mexico City, as well as for aged airmasses. Comparison of light absorption measured with a particle soot absorption photometer (PSAP) and the SP2 BC suggests a BC mass-normalized absorption cross-section (MAC) of 10.9±2.1 m2/g at 660 nm (or 13.1 m2/g @ 550 nm, assuming MAC is inversely dependent on wavelength). This appears independent of aging and similar to the expected absorption cross-section for aged BC, but values, particularly in fresh emissions, could be biased high due to instrument artifacts. SP2-derived BC coating indicators show a prominent thinly-coated BC mode over the Mexico City Metropolitan Area (MCMA), while older air masses show both thinly-coated and thickly-coated BC. Some 2-day-old plumes do not show a prominent thickly-coated BC mode, possibly due to preferential wet scavenging of the likely-hydrophilic thickly-coated BC.
Gurgel-Giannetti et al. describe a novel syndrome characterised by optic atrophy, sensory-motor neuropathy, recurrent rhabdomyolysis and reversible leukoencephalopathy, in two Brazilian families. ...Homozygosity mapping and exome sequencing reveal the cause to be a homozygous mutation in FDX2, which encodes a mitochondrial ferredoxin essential for iron-sulphur cluster biogenesis.
Abstract
Defects in iron-sulphur Fe-S cluster biogenesis are increasingly recognized as causing neurological disease. Mutations in a number of genes that encode proteins involved in mitochondrial Fe-S protein assembly lead to complex neurological phenotypes. One class of proteins essential in the early cluster assembly are ferredoxins. FDX2 is ubiquitously expressed and is essential in the de novo formation of 2Fe-2S clusters in humans. We describe and genetically define a novel complex neurological syndrome identified in two Brazilian families, with a novel homozygous mutation in FDX2. Patients were clinically evaluated, underwent MRI, nerve conduction studies, EMG and muscle biopsy. To define the genetic aetiology, a combination of homozygosity mapping and whole exome sequencing was performed. We identified six patients from two apparently unrelated families with autosomal recessive inheritance of a complex neurological phenotype involving optic atrophy and nystagmus developing by age 3, followed by myopathy and recurrent episodes of cramps, myalgia and muscle weakness in the first or second decade of life. Sensory-motor axonal neuropathy led to progressive distal weakness. MRI disclosed a reversible or partially reversible leukoencephalopathy. Muscle biopsy demonstrated an unusual pattern of regional succinate dehydrogenase and cytochrome c oxidase deficiency with iron accumulation. The phenotype was mapped in both families to the same homozygous missense mutation in FDX2 (c.431C > T, p.P144L). The deleterious effect of the mutation was validated by real-time reverse transcription polymerase chain reaction and western blot analysis, which demonstrated normal expression of FDX2 mRNA but severely reduced expression of FDX2 protein in muscle tissue. This study describes a novel complex neurological phenotype with unusual MRI and muscle biopsy features, conclusively mapped to a mutation in FDX2, which encodes a ubiquitously expressed mitochondrial ferredoxin essential for early Fe-S cluster biogenesis.
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