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The persistent use of MLCs through VMAT and IMRT is causing additional wear and tear on these mechanical parts, leading to an increase in MLC interlocks, breakdowns and failures. This study investigates the effect of an MLC clean and service procedure on MLC performance and positional accuracy demonstrated through in-house service logbook reports, Varian MLC backlash test results, daily MLC position QC results and Varian TrueBeam trajectory log file data. A service and clean of each individual MLC leaf was carried out on 3 standard MLC and 2 high definition MLC (HDMLC) Varian TrueBeam linacs. In-house service logbook reports, Varian backlash test results, daily MLC picket fence QC results and beam hold data from patient delivery trajectory log files were analysed for up to 6 months pre and 2 years post the MLC service/clean to assess the impact on unplanned MLC maintenance work and MLC performance. The median (range) of hardware faults reduced from 12 (1–17) pre clean to 0 (0–1) and 4 (1–11) at 12 and 24 months respectively for all linacs with the exception of a HDMLC linac where faults increased from 4 pre-clean to 13 and 20 again at 12 and 24 months respectively. The reduction in faults in the alternative 4 linacs was consistent with the reduction in the number of MLCs reaching the 0.3 mm and the 0.4 mm backlash recommendations in the first 12 and 24 months following the service/clean. The increase in faults in the HDMLC linac was also consistent with the increase in MLCs reaching the 0.3 mm backlash recommendation in the first 12 and 24 months. The median (range) of MLCs reaching a daily picket fence QC position tolerance of 0.25 mm reduced from 14 (1–40) pre clean to 0 (0) at both 12 and 24 months post-clean. This demonstrates the improvement in MLC performance caused by the MLC service/clean but also reveals factors other than MLC position accuracy influence hardware faults. Additionally, the number of beam hold-offs determined from patient delivery trajectory log files were found to have no correlation with the MLC service/clean. The MLC service/clean improves MLC performance and MLC position accuracy, reducing reactive repair work for engineering and physics staff. The results were maintained for 1 year post the MLC service/clean, with a trend back towards pre-clean levels in the subsequent 12–24 months. This suggests this preventative maintenance work could be performed at a frequency of > 2 years. This period of reduced faults and improved performance is significant given the 10 year expected lifespan of a linac.

Purpose:The aim of this study was to optimise patient dose and image quality of Varian TrueBeam cone beam computed tomography (CBCT) pelvis, thorax and head and neck (H&N) images based on patient size.Methods:An elliptical phantom of small, medium and large size was designed representative of a local population of pelvis, thorax and H&N patients. The phantom was used to establish the relationship between image noise, CT and CBCT exposure settings. Using this insight, clinical images were optimised in phases and the image quality graded qualitatively by radiographers. At each phase, the time required to match the images was recorded from the record and verify system.Results:Average patient diameter was a suitable metric to categorise patient size. Phantom measurements showed the power relationship between noise and CBCT exposure settings of value −0·15, −0·35 and −0·43 for thorax, pelvis and H&N, respectively. These quantitative phantom measurements provided confidence that phased variation of ~±20% in mAs should result in clinically usable images. Qualitative assessment of almost 2000 images reduced the exposure settings in H&N images by −50%, thorax images by up to −66% and pelvis images by up to −80%. These optimised CBCT settings did not affect the time required to match images.Findings:Varian TrueBeam CBCT mAs settings have been optimised for dose and image quality based on patient size for three treatment sites: pelvis, thorax and H&N. Quantitative phantom measurements provided insight into the magnitude of change to implement clinically. The final optimised exposure settings were determined from radiographer qualitative image assessment.

Variable gestation length in the mare poses a challenge for determination of fetal readiness for birth. The objectives of this study were to describe sonographic characteristics of the fetal GI tract in the late gestation mare and identify changes that occur with progressing fetal maturity. Based on these characteristics, a grading scale modeled after the existing human and canine scoring system was developed. Weekly sonographic examination of the fetus by one observer beginning 2–3 weeks prior to a calculated due date of 330 days was performed. Fetal assessment included; presence of stomach rugae, bowel segment definition (uniform echogenic, some defined, clearly defined), bowel segment dilation (none, segmental dilation), intestinal contents (none, mixed echogenicity) and peristalsis (none, occasional, every 3 s, continuous). Based on these characteristics a phase was assigned to the GI tract (1–5). Phase 1 was defined as a uniform echogenic grey area caudal to the diaphragm. The differentiation of Phase 2–5 was based primarily on the frequency of peristalsis, with Phase 2 exhibiting no peristalsis, Phase 3 exhibiting occasional peristalsis, Phase 4 exhibiting peristalsis every 3 s and Phase 5 exhibiting continuous peristalsis. Only data from mares with a normal parturition and healthy foals were included in the statistics (N = 10). Associations amongst sonographic fetal GI characteristics and days prepartum were validated using a simulation-based bootstrap approach with 1000 replicates using Stata 14. Stomach rugae, peristalsis, intestinal contents, tail head relaxation and udder development were all highly correlated with days prepartum. Using a multiple linear regression model, tail head relaxation and peristalsis predicted days prepartum with a 95% CI ± 6 days. The same model predicted days prepartum with a 95% CI ± 4 days when day of gestation, tail head relaxation and peristalsis were included as variables. Based on these findings, characterization of the fetal GI tract could provide valuable information concerning the maturity of the equine fetus. Further studies are needed comparing high risk mares to normal mares before this information could be used with confidence in the clinical setting.

Quality assurance of linear accelerators (linacs) is an important part of ensuring accurate radiotherapy treatment deliveries. The aim of this study is to investigate the role of gravity on the positional accuracy of multileaf collimator (MLC) leaves during complex radiotherapy treatments on linacs. This investigation is based on the analysis of the machine log files from five different linacs in multiple centers.Three main categories of deliveries were considered: Picket fence, volumetric modulated arc therapy (VMAT) (both delivering with continuous gantry rotation), and sliding gap tests delivered at cardinal gantry angles, to determine the error of the MLC in relation to the gantry angle.Analysis of picket fence tests revealed a dependence of the error upon the gantry angle. For the majority of deliveries, the MLC showed greater error at gantry angles 270 and 90. The errors computed for the cardinal angles for sliding gap tests were all statistically different with greatest error arising at gantry angle 270 and least error at gantry 90. For picket fence, sliding gap, and VMAT cases, MLC errors were dependent on the gantry angle.The errors in leaf positioning were found to be dependent on the gantry angle. For sliding gap tests, the error was greater at gantry angle 270° and 90° and less when the leaf motion was perpendicular to the force of gravity.

Paid community health workers screened for hypertension in the community, referred cases to the clinic for diagnosis and initial treatment by a physician, and then monitored patients who had well-controlled blood pressure including dispensing maintenance medications prescribed by the physician. Blood pressure control was successful in the majority of such patients., Poor blood pressure control results in tremendous morbidity and mortality in India where the leading cause of death among adults is from coronary heart disease. Despite having little formal education, community health workers (CHWs) are integral to successful public health interventions in India and other low- and middle-income countries that have a shortage of trained health professionals. Training CHWs to screen for and manage chronic hypertension, with support from trained clinicians, offers an excellent opportunity for effecting systemwide change in hypertension-related burden of disease. In this article, we describe the development of a program that trained CHWs between 2014 and 2015 in the tribal region of the Sittilingi Valley in southern India, to identify hypertensive patients in the community, refer them for diagnosis and initial management in a physician-staffed clinic, and provide them with sustained lifestyle interventions and medications over multiple visits. We found that after 2 years, the CHWs had screened 7,176 people over age 18 for hypertension, 1,184 (16.5%) of whom were screened as hypertensive. Of the 1,184 patients screened as hypertensive, 898 (75.8%) had achieved blood pressure control, defined as a systolic blood pressure less than 140 and a diastolic blood pressure less than 90 sustained over 3 consecutive visits. While all of the 24 trained CHWs reported confidence in checking blood pressure with a manual blood pressure cuff, 4 of the 24 CHWs reported occasional difficulty documenting blood pressure values because they were unable to write numbers properly. They compensated by asking other CHWs or members of their community to help with documentation. Our experience and findings suggest that a CHW blood pressure screening system linked to a central clinic can be a promising avenue for improving hypertension control rates in low- and middle-income countries.

© 2017 The Author(s). Microorganisms can catabolize a wide range of organic compounds and therefore have the potential to perform many industrially relevant bioconversions. One barrier to realizing the potential of biorefining strategies lies in our incomplete knowledge of metabolic pathways, including those that can be used to assimilate naturally abundant or easily generated feedstocks. For instance, levulinic acid (LA) is a carbon source that is readily obtainable as a dehydration product of lignocellulosic biomass and can serve as the sole carbon source for some bacteria. Yet, the genetics and structure of LA catabolism have remained unknown. Here, we report the identification and characterization of a seven-gene operon that enables LA catabolism in Pseudomonas putida KT2440. When the pathway was reconstituted with purified proteins, we observed the formation of four acyl-CoA intermediates, including a unique 4-phosphovaleryl-CoA and the previously observed 3-hydroxyvaleryl-CoA product. Using adaptive evolution, we obtained a mutant of Escherichia coli LS5218 with functional deletions of fadE and atoC that was capable of robust growth on LA when it expressed the five enzymes from the P. putida operon. This discovery will enable more efficient use of biomass hydrolysates and metabolic engineering to develop bioconversions using LA as a feedstock.

Background Patients treated with radiotherapy for head and neck (H&N) cancer often experience anatomical changes. The potential compromises to Planning Target Volume (PTV) coverage or Organ at Risk (OAR) sparing has prompted the use of adaptive radiotherapy (ART) for these patients. However, implementation of ART is time and resource intensive. This study seeks to define a clinical trigger for H&N re-plans based on spinal cord safety using kV Cone-Beam Computed Tomography (CBCT) verification imaging, in order to best balance clinical benefit with additional workload. Methods Thirty-one H&N patients treated with Volumetric Modulated Arc Therapy (VMAT) who had a rescan CT (rCT) during treatment were included in this study. Contour volume changes between the planning CT (pCT) and rCT were determined. The original treatment plan was calculated on the pCT, CBCT prior to the rCT, pCT deformed to the anatomy of the CBCT (dCT), and rCT (considered the gold standard). The dose to 0.1 cc (D0.1cc) spinal cord was evaluated from the Dose Volume Histograms (DVHs). Results The median dose increase to D0.1cc between the pCT and rCT was 0.7 Gy (inter-quartile range 0.2–1.9 Gy, p Conclusions An adaptive re-plan can be triggered using spinal cord doses calculated on the CBCT/dCT. Implementing this trigger can reduce patient appointments and radiation dose by eliminating up to 90% of additional un-necessary CT scans, reducing the workload for radiographers, physicists, dosimetrists, and clinicians.

OBJECTIVE:: To assess the accuracy and efficiency of four different techniques, thus determining the optimum method for recalculating dose on cone beam CT (CBCT) images acquired during radiotherapy treatments.METHODS:: Four established techniques were investigated and their accuracy assessed via dose calculations: (1) applying a standard planning CT (pCT) calibration curve, (2) applying a CBCT site-specific calibration curve, (3) performing a density override and (4) using deformable registration. Each technique was applied to 15 patients receiving volumetric modulated arc therapy to one of three treatment sites, head and neck, lung and prostate. Differences between pCT and CBCT recalculations were determined with dose volume histogram metrics and 2.0%/0.1 mm gamma analysis using the pCT dose distribution as a reference.RESULTS:: Dose volume histogram analysis indicated that all techniques yielded differences from expected results between 0.0 and 2.3% for both target volumes and organs at risk. With volumetric gamma analysis, the dose recalculation on deformed images yielded the highest pass-rates. The median pass-rate ranges at 50% threshold were 99.6-99.9%, 94.6-96.0%, and 94.8.0-96.0% for prostate, head and neck and lung patients, respectively.CONCLUSION:: Deformable registration, HU override and site-specific calibration curves were all identified as dosimetrically accurate and efficient methods for dose calculation on CBCT images.ADVANCES IN KNOWLEDGE:: With the increasing adoption of CBCT, this study provides clinical radiotherapy departments with invaluable information regarding the comparison of dose reconstruction methods, enabling a more accurate representation of a patient's treatment. It can also integrate studies in which CBCT is used in image-guided radiation therapy and for adaptive radiotherapy planning processes.

The objective of this study is to identify promising strategies for improving drinking-water access and consumption among children aged 0 to 5 years. MEDLINE/PubMed, Embase, ERIC, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Science, and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched in this review. Studies included peer-reviewed, full-text studies from high-income countries, published in English between January 1, 2000, and January 12, 2018, that evaluated interventions to increase water access or consumption in children aged 0 to 5 years. Twenty-five studies met inclusion criteria; 19 used an effective intervention strategy to increase water access or water consumption. Three studies addressed both water access and consumption. Frequently used strategies included policy and practice changes, increasing water access and convenience, and education, training, or social support for caregivers. Studies were of fair methodological quality (average score: 18.8 of 26) for randomized studies and of moderate quality (5.1 of 9) for non-randomized studies. To date, few high-quality studies with objectively measured outcomes have clearly demonstrated strategies that may influence water intake and consumption among young children aged 0 to 5 years.

Wavelet entropy assesses the degree of order or disorder in signals and presents this complex information in a simple metric. Relative wavelet entropy assesses the similarity between the spectral distributions of two signals, again in a simple metric. Wavelet entropy is therefore potentially a very attractive tool for waveform analysis. The ability of this method to track the effects of pharmacologic modulation of vascular function on Doppler blood velocity waveforms was assessed. Waveforms were captured from ophthalmic arteries of 10 healthy subjects at baseline, after the administration of glyceryl trinitrate (GTN) and after two doses of NG-nitro-L-arginine-methyl ester (L-NAME) to produce vasodilation and vasoconstriction, respectively. Wavelet entropy had a tendency to decrease from baseline in response to GTN, but significantly increased after the administration of L-NAME (mean: 1.60 ± 0.07 after 0.25 mg/kg and 1.72 ± 0.13 after 0.5 mg/kg vs. 1.50 ± 0.10 at baseline, p < 0.05). Relative wavelet entropy had a spectral distribution from increasing doses of L-NAME comparable to baseline, 0.07 ± 0.04 and 0.08 ± 0.03, respectively, whereas GTN had the most dissimilar spectral distribution compared with baseline (0.17 ± 0.08, p = 0.002). Wavelet entropy can detect subtle changes in Doppler blood velocity waveform structure in response to nitric-oxide-mediated changes in arteriolar smooth muscle tone.

The motivation for this study was to reduce physics workload relating to patient- specific quality assurance (QA). VMAT plan delivery accuracy was determined from analysis of pre- and on-treatment trajectory log files and phantom-based ionization chamber array measurements. The correlation in this combination of measurements for patient-specific QA was investigated. The relationship between delivery errors and plan complexity was investigated as a potential method to further reduce patient-specific QA workload. Thirty VMAT plans from three treatment sites - prostate only, prostate and pelvic node (PPN), and head and neck (H&N) - were retrospectively analyzed in this work. The 2D fluence delivery reconstructed from pretreatment and on-treatment trajectory log files was compared with the planned fluence using gamma analysis. Pretreatment dose delivery verification was also car- ried out using gamma analysis of ionization chamber array measurements compared with calculated doses. Pearson correlations were used to explore any relationship between trajectory log file (pretreatment and on-treatment) and ionization chamber array gamma results (pretreatment). Plan complexity was assessed using the MU/ arc and the modulation complexity score (MCS), with Pearson correlations used to examine any relationships between complexity metrics and plan delivery accu- racy. Trajectory log files were also used to further explore the accuracy of MLC and gantry positions. Pretreatment 1%/1 mm gamma passing rates for trajectory log file analysis were 99.1% (98.7%-99.2%), 99.3% (99.1%-99.5%), and 98.4% (97.3%-98.8%) (median (IQR)) for prostate, PPN, and H&N, respectively, and were significantly correlated to on-treatment trajectory log file gamma results (R = 0.989, p < 0.001). Pretreatment ionization chamber array (2%/2 mm) gamma results were also significantly correlated with on-treatment trajectory log file gamma results (R = 0.623, p < 0.001). Furthermore, all gamma results displayed a significant correlation with MCS (R > 0.57, p < 0.001), but not with MU/arc. Average MLC position and gantry angle errors were 0.001 ± 0.002 mm and 0.025° ± 0.008° over all treatment sites and were not found to affect delivery accuracy. However, vari- ability in MLC speed was found to be directly related to MLC position accuracy. The accuracy of VMAT plan delivery assessed using pretreatment trajectory log file fluence delivery and ionization chamber array measurements were strongly correlated with on-treatment trajectory log file fluence delivery. The strong corre- lation between trajectory log file and phantom-based gamma results demonstrates potential to reduce our current patient-specific QA. Additionally, insight into MLC and gantry position accuracy through trajectory log file analysis and the strong cor- relation between gamma analysis results and the MCS could also provide further methodologies to both optimize the VMAT planning and QA process.

This work investigated the differences between multileaf collimator (MLC) positioning accuracy determined using either log files or electronic portal imaging devices (EPID) and then assessed the possibility of reducing patient specific quality control (QC) via phantom-less methodologies. In-house software was developed, and validated, to track MLC positional accuracy with the rotational and static gantry picket fence tests using an integrated electronic portal image. This software was used to monitor MLC daily performance over a 1 year period for two Varian TrueBeam linear accelerators, with the results directly compared with MLC positions determined using leaf trajectory log files. This software was validated by introducing known shifts and collimator errors. Skewness of the MLCs was found to be 0.03 ± 0.06° (mean ±1 standard deviation (SD)) and was dependent on whether the collimator was rotated manually or automatically. Trajectory log files, analysed using in-house software, showed average MLC positioning errors with a magnitude of 0.004 ± 0.003 mm (rotational) and 0.004 ± 0.011 mm (static) across two TrueBeam units over 1 year (mean ±1 SD). These ranges, as indicated by the SD, were lower than the related average MLC positioning errors of 0.000 ± 0.025 mm (rotational) and 0.000 ± 0.039 mm (static) that were obtained using the in-house EPID based software. The range of EPID measured MLC positional errors was larger due to the inherent uncertainties of the procedure. Over the duration of the study, multiple MLC positional errors were detected using the EPID based software but these same errors were not detected using the trajectory log files. This work shows the importance of increasing linac specific QC when phantom-less methodologies, such as the use of log files, are used to reduce patient specific QC. Tolerances of 0.25 mm have been created for the MLC positional errors using the EPID-based automated picket fence test. The software allows diagnosis of any specific leaf that needs repair and gives an indication as to the course of action that is required.

Purpose The dose delivery accuracy of 30 clinical step and shoot intensity modulated radiation therapy plans was investigated using the single integrated multileaf collimator controller of the Varian Truebeam linear accelerator (linac) (Varian Medical Systems, Palo Alto, CA) and compared with the dose delivery accuracy on a previous generation Varian 2100CD C-Series linac. Methods and Materials Ten prostate, 10 prostate and pelvic node, and 10 head-and-neck cases were investigated in this study. Dose delivery accuracy on each linac was assessed using Farmer ionization chamber point dose measurements, 2-dimensional planar ionization chamber array measurements, and the corresponding Varian dynamic log files. Absolute point dose measurements, fluence delivery accuracy, leaf position accuracy, and the overshoot effect were assessed for each plan. Results Absolute point dose delivery accuracy increased by 1.5% on the Truebeam compared with the 2100CD linac. No improvement in fluence delivery accuracy between the linacs, at a gamma criterion of 3%/3 mm was measured using the 2-dimensional ionization chamber array, with median (interquartile range) gamma passing rates of 98.99% (97.70%-99.72%) and 99.28% (98.26%-99.75%) for the Truebeam and 2100CD linacs, respectively. Varian log files also showed no improvement in fluence delivery between the linacs at 3%/3 mm, with median gamma passing rates of 99.97% (99.93%-99.99%) and 99.98% (99.94%-100%) for the Truebeam and 2100CD linacs, respectively. However, log files revealed improved leaf position accuracy and fluence delivery at 1%/1 mm criterion on the Truebeam (99.87%; 99.78%-99.94%) compared with the 2100CD linac (97.87%; 91.93%-99.49%). The overshoot effect, characterized on the 2100CD linac, was not observed on the Truebeam. Conclusions The integrated multileaf collimator controller on the Varian Truebeam improves clinical treatment delivery accuracy of step and shoot intensity modulated radiation therapy fields compared with delivery on a Varian C-series linac.

Discovered in the 1920s, polyhydroxyalkanoates (PHA) are a naturally occurring class of biopolyesters that have long been touted as a renewable, biodegradable plastic alternative. Demand for sustainable products and over a half century of research have led to moderate commercial success of PHA. Yet, these materials are not pervasive. Therefore, an important question to address is, “what is the barrier that prevents widespread application of these materials?” PHA can be made from an incredibly diverse class of monomers that incorporate both simple and complex organic acids. Herein, we provide an updated list of unique PHA monomers that are substrates for a PHA polymerase. Unfortunately, most unique monomers are incorporated only after feeding a structurally related feedstock to a PHA accumulating bacterium. Therefore, we put forward an argument that research must now turn to developing feedstock-independent, synthetic pathways to produce an increased diversity of PHAs capable of competing with petroleum-derived plastics.

The aim of this work was to track and verify the delivery of respiratory-gated irradiations, performed with three versions of TrueBeam linac, using a novel phantom arrangement that combined the OCTAVIUS(®) SRS 1000 array with a moving platform. The platform was programmed to generate sinusoidal motion of the array. This motion was tracked using the real-time position management (RPM) system and four amplitude gating options were employed to interrupt MV beam delivery when the platform was not located within set limits. Time-resolved spatial information extracted from analysis of x-ray fluences measured by the array was compared to the programmed motion of the platform and to the trace recorded by the RPM system during the delivery of the x-ray field. Temporal data recorded by the phantom and the RPM system were validated against trajectory log files, recorded by the linac during the irradiation, as well as oscilloscope waveforms recorded from the linac target signal. Gamma analysis was employed to compare time-integrated 2D x-ray dose fluences with theoretical fluences derived from the probability density function for each of the gating settings applied, where gamma criteria of 2%/2 mm, 1%/1 mm and 0.5%/0.5 mm were used to evaluate the limitations of the RPM system. Excellent agreement was observed in the analysis of spatial information extracted from the SRS 1000 array measurements. Comparisons of the average platform position with the expected position indicated absolute deviations of 0.5 mm for all four gating settings. Differences were observed when comparing time-resolved beam-on data stored in the RPM files and trajectory logs to the true target signal waveforms. Trajectory log files underestimated the cycle time between consecutive beam-on windows by 10.0 ± 0.8 ms. All measured fluences achieved 100% pass-rates using gamma criteria of 2%/2 mm and 50% of the fluences achieved pass-rates 90% when criteria of 0.5%/0.5 mm were used. Results using this novel phantom arrangement indicate that the RPM system is capable of accurately gating x-ray exposure during the delivery of a fixed-field treatment beam.

This work investigated the delivery accuracy of different Varian linear accelerator models using log file-derived multileaf collimator (MLC) root mean square (RMS) values.Seven centres independently created a plan on the same virtual phantom using their own planning system, and the log files were analyzed following delivery of the plan in each centre to assess MLC positioning accuracy. A single standard plan was also delivered by the seven centres to remove variations in complexity, and the log files were analyzed for Varian TrueBeams and Clinacs (2300IX or 2100CD models).Varian TrueBeam accelerators had better MLC positioning accuracy (1.0 mm) than the 2300IX (2.5 mm) following delivery of the plans created by each centre and also the standard plan. In one case, log files provided evidence that reduced delivery accuracy was not associated with the linear accelerator model but was due to planning issues.Log files are useful in identifying differences between linear accelerator models and isolate errors during end-to-end testing in volumetric-modulated arc therapy (VMAT) audits. Log file analysis can rapidly eliminate the machine delivery from the process and divert attention with confidence to other aspects.Log file evaluation was shown to be an effective method to rapidly verify satisfactory treatment delivery when a dosimetric evaluation fails during end-to-end dosimetry audits. MLC RMS values for Varian TrueBeams were shown to be much smaller than those for Varian Clinacs for VMAT deliveries.

Demand for sustainable materials motivates the development of microorganisms capable of synthesizing products from renewable substrates. A challenge to commercial production of polyhydroxyalkanoates (PHA), microbially derived polyesters, is engineering metabolic pathways to produce a polymer with the desired monomer composition from an unrelated and renewable source. Here, we demonstrate a metabolic pathway for converting glucose into medium-chain-length (mcl)-PHA composed primarily of 3-hydroxydodecanoate monomers. This pathway combines fatty acid biosynthesis, an acyl-ACP thioesterase to generate desired C12 and C14 fatty acids, β-oxidation for conversion of fatty acids to (R)-3-hydroxyacyl-CoAs, and a PHA polymerase. A key finding is that Escherichia coli expresses multiple copies of enzymes involved in β-oxidation under aerobic conditions. To produce polyhydroxydodecanoate, an acyl-ACP thioesterase (BTE), an enoyl-CoA hydratase (phaJ3), and mcl-PHA polymerase (phaC2) were overexpressed in E. coli ΔfadRABIJ. Yields were improved through expression of an acyl-CoA synthetase resulting in production over 15% CDW – the highest reported production of mcl-PHA of a defined composition from an unrelated carbon source.

This study aims to evaluate the use of Varian radiotherapy dynamic treatment log (DynaLog) files to verify IMRT plan delivery as part of a routine quality assurance procedure. Delivery accuracy in terms of machine performance was quantified by multileaf collimator (MLC) position errors and fluence delivery accuracy for patients receiving intensity modulated radiation therapy (IMRT) treatment. The relationship between machine performance and plan complexity, quantified by the modulation complexity score (MCS) was also investigated. Actual MLC positions and delivered fraction of monitor units (MU), recorded every 50 ms during IMRT delivery, were extracted from the DynaLog files. The planned MLC positions and fractional MU were taken from the record and verify system MLC control file. Planned and delivered beam data were compared to determine leaf position errors with and without the overshoot effect. Analysis was also performed on planned and actual fluence maps reconstructed from the MLC control file and delivered treatment log files respectively. This analysis was performed for all treatment fractions for 5 prostate, 5 prostate and pelvic node (PPN) and 5 head and neck (H&N) IMRT plans, totalling 82 IMRT fields in ∼5500 DynaLog files. The root mean square (RMS) leaf position errors without the overshoot effect were 0.09, 0.26, 0.19 mm for the prostate, PPN and H&N plans respectively, which increased to 0.30, 0.39 and 0.30 mm when the overshoot effect was considered. Average errors were not affected by the overshoot effect and were 0.05, 0.13 and 0.17 mm for prostate, PPN and H&N plans respectively. The percentage of pixels passing fluence map gamma analysis at 3%/3 mm was 99.94 ± 0.25%, which reduced to 91.62 ± 11.39% at 1%/1 mm criterion. Leaf position errors, but not gamma passing rate, were directly related to plan complexity as determined by the MCS. Site specific confidence intervals for average leaf position errors were set at −0.03–0.12 mm for prostate and −0.02–0.28 mm for more complex PPN and H&N plans. For all treatment sites confidence intervals for RMS errors with the overshoot was set at 0–0.50 mm and for the percentage of pixels passing a gamma analysis at 1%/1 mm a confidence interval of 68.83% was set also for all treatment sites. This work demonstrates the successful implementation of treatment log files to validate IMRT deliveries and how dynamic log files can diagnose delivery errors not possible with phantom based QC. Machine performance was found to be directly related to plan complexity but this is not the dominant determinant of delivery accuracy.

Diabetic retinopathy is associated with markedly increased risk of cardiovascular events. Analysis of retrobulbar blood velocity waveforms should help characterise microvessels since waveform morphology is partly determined by wave reflection. This approach could potentially allow the detection of abnormalities earlier than is currently possible. Ultrasound examinations of the common carotid, ophthalmic (OA) and central retinal (CRA) arteries were undertaken on 39 subjects with type 1 diabetes (no retinopathy) and 39 controls. Waveforms were characterised using the discrete wavelet transform, and frequency data categorised into 11 bands. After correcting for possible confounders, in the OA, the mean amplitude was higher for subjects with diabetes in band 4 (p=0.022). In the CRA, the mean amplitude was higher for subjects with diabetes in bands 2 (p=0.012), 3 (p

Please cite this paper as: Quinn, Hamilton, McCann, Agnew, Millar, Lockhart, Harbinson and McVeigh (2011). Ocular Blood Flow Analysis Detects Microvascular Abnormalities in Impaired Glucose Tolerance. Microcirculation 18(7), 532–540. Abstract Objective: Waveform analysis has been used to assess vascular resistance and predict cardiovascular events. We aimed to identify microvascular abnormalities in patients with IGT using ocular waveform analysis. The effects of pioglitazone were also assessed. Methods: Forty patients with IGT and 24 controls were studied. Doppler velocity recordings were obtained from the central retinal, ophthalmic, and common carotid arteries, and sampled at 200 Hz. A discrete wavelet-based analysis method was employed to quantify waveforms. The RI was also determined. Patients with IGT were randomized to pioglitazone or placebo, and measurements were repeated after 12-week treatment. Results: In the ocular waveforms, significant differences in power spectra were observed in frequency band 4 (corresponding to frequencies between 6.25 and 12.50 Hz) between groups (p

Background: Flow-mediated dilatation (FMD) of the brachial artery is commonly measured as a surrogate marker of endothelial function. Its measurement is, however, technically demanding and reports regarding its reproducibility have not always been favourable. Aim: Two Type I diabetes and control group comparator studies were conducted to assess the reproducibility of FMD and to analyse blood flow data normally discarded during FMD measurement. Design: The studies were sequential and differed only with regard to operator and ultrasound machine. Seventy-two subjects with diabetes and 71 controls were studied in total. Methods: Subjects had FMD measured conventionally. Blood velocity waveforms were averaged over 10 pulses post forearm ischaemia and their component frequencies analysed using the wavelet transform, a mathematical tool for waveform analysis. The component frequencies were grouped into 11 bands to facilitate analysis. Results: Subjects were well-matched between studies. In Study 1, FMD was significantly impaired in subjects with Type I diabetes vs. controls (median 4.35%, interquartile range 3.10–4.80 vs. 6.50, 4.79–9.42, P

The temperature and time dependence of single-walled carbon nanotube (SWCNT) growth by chemical vapor deposition of ethanol on Fe2O3/MgO catalyst are compared at both low (∼27 Pa) and atmospheric pressure limits. SWCNTs are synthesized in two reactors with different geometries and operating pressures and are characterized by Raman spectroscopy. Both reactors show SWCNT growth within a relatively narrow temperature window of 700–850 °C, with an optimum growth time of 35 min for the cold wall reactor and 75 min for the quartz tube reactor. A kinetic model comprising of ethanol decomposition, SWCNT formation, and water etching is developed to better understand the growth mechanism. The existence of a temperature window and an optimum growth time in both reactors can be well described by the kinetic model. Simulation results suggest that the temperature and time dependence can be explained by the competition between the growth of SWCNTs and that of amorphous carbon.

Increasingly complex radiotherapy techniques require additional machine-specific quality control (QC). The extra time required for such tests is in addition to existing, well-established QC required for standard linac deliveries. Additional time for QC can be in direct conflict with current cost saving driven practice and patient scheduling. One approach to create additional time for machine specific QC is to review current processes and the frequencies of well-established QC tests. In this work, the potential to transfer radiation field size, asymmetric jaw alignment, multi-leaf collimator (MLC) transmission and MLC rotation tests from film analysis to analysis of digital EPID images was investigated. In-house software was developed in MATLAB® and commissioned for each test by comparison to film. Following commissioning, EPID analysis was introduced into routine use and the results and trends for these tests from 10 Varian linacs were analysed over 5 yr. Radiation field size measurements were found to be smaller than film due to the steeper penumbra in EPID profiles. This effect was field size dependent. By correcting for this, EPID and film measurements agreed within 0.0 ± 0.5 mm (mean ± 1SD), with drifts of ≤0.3 mm yr−1 in field size measurements. The EPID profile response also results in overestimation of asymmetric jaw alignment measurements, which when accounted for permitted the junction gap to be maintained within ±2 mm. Junction gap was found to drift at

Clinical and experimental studies indicate that structural and functional changes in the microvasculature can predate or accompany risk factors for cardiovascular disease at the earliest stages in the disease process. In the current work, both simulated and actual Doppler ultrasound maximum blood velocity waveform envelopes recorded from the ophthalmic artery were analysed using a root-MUSIC and least squares fitting approach to determine amplitude frequency spectra. Both amplitude and frequency components of noise contaminated simulated waveforms were reliably determined indicating the robustness of the technique. The technique was then used to compare the spectral content of the ophthalmic artery blood velocity waveforms of normal controls in three test states: at baseline, following administration of GTN, a nitric oxide donor, and following administration of L-Name, a nitric oxide inhibitor. Principal components derived from root-MUSIC analysis discriminated between waveforms in baseline and non-baseline test states (p < 0.00001) and between GTN and non-GTN test states (p = 0.0002).

SUMMARYEmpty body (EB) composition data from 146 lactating Holstein–Friesian dairy cows were analysed, with cows selected from a large herd to represent a wide range of animal factors including parity, live weight (LW), body condition score (BCS), milk yield and stage of lactation. The objectives of the study were to examine possible relationships between EB composition and live animal characteristics and to develop prediction equations for EB weight (EBW) and EB composition. EBW was strongly related to LW with a R2 of 0·90, and addition of BCS and stage of lactation increased the R2 to 0·93 and reduced the s.e. value from 19·8 to 16·8. There was a strong relationship between LW and EB mass of crude protein (CP) or water (R2=0·89 or 0·85), and addition of BCS, milk yield and stage of lactation as supporting predictors gave little improvement in the relationship between LW and EB mass of CP or water. Similar results were also obtained for the prediction of EB ash mass, but the relationship between EB ash mass and LW or a combination of LW and parity was relatively poor (R2=0·59 or 0·63). However, including BCS and milk yield as supporting predictors in the linear relationship between LW and EB masses of lipid (0·51 v. 0·79) and dry matter (DM) (0·79 v. 0·91) and total gross energy (GE) content (0·66 v. 0·85) considerably increased the R2 values. Similar linear and multiple relationships were also developed to predict EB component proportions of lipid, CP, GE, DM and water, and the R2 values were much smaller than those for EB component masses. The equations for prediction of EB component masses were evaluated through internal validation, by developing a range of similar new equations from two-thirds of the present data and then validating these new equations with the remaining one-third of data. The validation indicated that addition of other live animal factors to support LW to predict EBW and EB masses of lipid, GE and DM considerably increased the prediction accuracy, but had little effect on the prediction accuracy for EB masses of CP, water and ash. It is concluded that in lactating dairy cows, LW is a very good predictor of EB masses of CP and water. Accurate prediction of EBW and EB masses of lipid, GE and DM can be obtained using LW together with BCS, milk yield and stage of lactation.

Deposition distribution variability strongly influences data from radioaerosol mucus clearance measurements. We investigated how one clearance measurement-the area under the 0-6 h tracheobronchial retention curve (AUC)-relates to three different indices characterizing initial particle distribution. These indices were a conventional penetration index (PI), retention at 24 h (R(24)) and an Airways Penetration Index (API). API is an estimate of an outer to inner zone ratio for "tracheobronchial" (short-term cleared) deposition. Data were analyzed from "control" tests on 35 normal nonsmoking volunteers (16 females, 19 males, age 18-72 years). The strongest clearance-deposition correlation (r = 0.84, p0.0001) was obtained with API, yielding a narrower normal range than those with PI or R(24). No influence of age was detected. Data from repeat tests on 17 subjects demonstrated AUC changes correlating closely with API changes (r = 0.92, p0.0001), confirming the potential value of API as a "predictor" of clearance changes resulting simply from a changed distribution of initial deposition along the tracheobronchial airway generations. Additional data from 19 "placebo" tests on normal subjects gave AUC values within or close to suggested normal confidence limits derived from the control subject plots of AUC against, respectively, PI, R(24), and API. Quantitative attention to the influence of depositionclearance relationships should help in analyzing data from studies where posttreatment aerosol distribution cannot be exactly matched to the pretreatment situation. Deposition-corrected clearance provides an approach to improved estimation of clearance "normality."

The electrophoretic mobilities of single-walled carbon nanotubes (SWNTs) in agarose gels subjected to negatively charged covalent functionalization and noncovalent anionic surfactant adsorption are compared using a simplified hydrodynamic model. Net charges are calculated on the basis of estimated friction coefficients for cylindrical rodlike particles. The effects of functionalization with negatively charged 4-hydroxybenzene diazonium and anionic sodium cholate are quantified and compared with model predictions. The adsorption of Na+ counterions into the nonionic surfactant layer adsorbed on SWNTs (Triton-X-405) is shown to induce a positive charge and reverse the mobility under select conditions. This effect has not been identified or quantified for nanoparticle systems and may be important in the processing of these systems.

The objective of this study was to compare the clinical and bacteriological cure rates of cows with clinical mastitis following treatment with either tylosin base (5 g injected 3 times at 24-h intervals; n = 306) or penethamate hydriodide (5 g injected 3 times at 24-h intervals; n = 289). Duplicate milk samples were collected before treatment and again 14 +/- 3 and 21 +/- 3 d later for microbiological analysis. Only those quarters from which gram-positive mastitis pathogens were isolated before treatment were included in the analyses. Streptococcus uberis was the most prevalent isolate. The number of cows with clinical failure (i.e., retreated within 21 d of enrollment) did not differ between treatments (64 vs. 63, respectively). At the quarter level, there was no difference in the proportion of bacteriological cure between treatments (81.2 vs. 83.8% for penethamate hydriodide or tylosin, respectively). The proportions of clinical and bacteriological cure were influenced by age, herd, severity of mastitis, number of glands within the cow with clinical mastitis, bacterial species, and days postpartum at enrollment. There was no difference between treatment groups for SCC (4.46 vs. 4.44 +/- 0.08, mean +/- standard error of the difference in ln SCC for cows treated with penethamate hydriodide or tylosin, respectively) or production of milk solids (1.45 vs. 1.48 +/- 0.02 kg/d of milk fat + protein, for the penethamate hydriodide or tylosin treatment, respectively). Overall, there was no difference in the proportions of clinical failure (17.3 vs. 16.5% of cows treated with penethamate hydriodide or tylosin, respectively) or bacteriological cure (79.8 vs. 82.0% of cows treated with penethamate hydriodide or tylosin, respectively), or in SCC or milk production between dairy cows with clinical mastitis and those treated for clinical mastitis with 1 of 2 parenteral antibiotic therapies.

To demonstrate the benefit of complexity metrics such as the modulation complexity score (MCS) and monitor units (MUs) in multi-institutional audits of volumetric-modulated arc therapy (VMAT) delivery.39 VMAT treatment plans were analysed using MCS and MU. A virtual phantom planning exercise was planned and independently measured using the PTW Octavius(®) phantom and seven29(®) 2D array (PTW-Freiburg GmbH, Freiburg, Germany). MCS and MU were compared with the median gamma index pass rates (2%/2 and 3%/3 mm) and plan quality. The treatment planning systems (TPS) were grouped by VMAT modelling being specifically designed for the linear accelerator manufacturer's own treatment delivery system (Type 1) or independent of vendor for VMAT delivery (Type 2). Differences in plan complexity (MCS and MU) between TPS types were compared.For Varian(®) linear accelerators (Varian(®) Medical Systems, Inc., Palo Alto, CA), MCS and MU were significantly correlated with gamma pass rates. Type 2 TPS created poorer quality, more complex plans with significantly higher MUs and MCS than Type 1 TPS. Plan quality was significantly correlated with MU for Type 2 plans. A statistically significant correlation was observed between MU and MCS for all plans (R = -0.84, p 0.01).MU and MCS have a role in assessing plan complexity in audits along with plan quality metrics. Plan complexity metrics give some indication of plan deliverability but should be analysed with plan quality.Complexity metrics were investigated for a national rotational audit involving 34 institutions and they showed value. The metrics found that more complex plans were created for planning systems which were independent of vendor for VMAT delivery.

Purpose To provide a tool to enable gamma analysis software algorithms to be included in a quality assurance (QA) program. Methods Four image sets were created comprising two geometric images to independently test the distance to agreement (DTA) and dose difference (DD) elements of the gamma algorithm, a clinical step and shoot IMRT field and a clinical VMAT arc. The images were analysed using global and local gamma analysis with 2 in-house and 8 commercially available software encompassing 15 software versions. The effect of image resolution on gamma pass rates was also investigated. Results All but one software accurately calculated the gamma passing rate for the geometric images. Variation in global gamma passing rates of 1% at 3%/3mm and over 2% at 1%/1mm was measured between software and software versions with analysis of appropriately sampled images. Conclusion This study provides a suite of test images and the gamma pass rates achieved for a selection of commercially available software. This image suite will enable validation of gamma analysis software within a QA program and provide a frame of reference by which to compare results reported in the literature from various manufacturers and software versions.

Healthcare institutions currently demonstrate increasing attention to risk analysis and risk management. A particular manifestation for English public sector healthcare providers was a “Controls Assurance” risk assessment and action planning framework. This required annual, very detailed, reports to central government, spanning 22 major areas from infection control to fire safety. Much of this framework continues into a successor system giving greater local flexibility but “regulated” via significant external audit. To help establish an analytical approach suitable for the new requirements, we have attempted to dissect out factors strongly influencing risk judgements made for Controls Assurance. Focussing on the “Medical Devices Management” area, which required a particularly detailed self‐assessment against 31 specified criteria, we paid close attention to issues of process (policies and committees) as against outcome (appropriate equipment operated by a trained practitioner). We also reviewed organisati...

Purpose. This research provided a detailed analysis of the types of questions and verbal strategies used by police officers and caregivers when interviewing children with intellectual disabilities about events. Method. Twenty eight children aged 9 to 13 years with a mild or moderate intellectual disability participated in a staged event at their school. Each child was then interviewed on separate occasions by the child's primary caregiver and by a police officer who was authorized to conduct investigative interviews with children. Results. While the approach used by the police officers was broadly consistent with best-practice recommendations (i.e. their interviews contained few leading, coercive or negative strategies), they frequently interrupted the child's account and used relatively few minimal encouragers and other strategies designed to keep the child talking. The caregivers used a high proportion of direct, leading and coercive strategies to elicit information from their children. Even when caregivers used open-ended questions, their children provided less event-related information than they did to the police interviewers. Conclusion. The quality of evidence obtained from children with intellectual disabilities is likely to be dependent (albeit in part) on the degree to which police interviewers adhere to best-practice guidelines, as well as the children's general experience with an open-ended style of communication.

In addition to breathlessness and cough, excessive mucus production is one of the main symptoms of chronic obstructive pulmonary disease (COPD). Excess mucus coupled with deteriorating mucociliary clearance is associated with a decline in lung function and an increased risk of death from pulmonary infection. The effect of Viozan (Sibenadet HCl, AR-C68397AA), a novel dual D2 dopamine receptor, beta2-adrenoceptor agonist, on mucociliary clearance was investigated together with that of a beta2-adrenoceptor agonist, salbutamol. Using a double blind, parallel group study design, 15 patients with COPD, all habitual smokers, were randomised to receive nebulised sidenadet (3mg tid; n = 7) or salbutamol (5mg tid; n = 8) for 10 days. Lung mucociliary clearance rates were measured, by a standard radioaerosol technique, before and after the treatment period, as were 24-h sputum volumes. Both sibenadet and salbutamol therapies resulted in significant (P

The rate constants for hydrolysis of diazomethane, diazoethane and 1-diazopropane in aqueous 5% acetonitrile at 25°C and ionic strength 1 M (NaClO4) were measured by stopped-flow spectrophotometry. The pH-rate profile for diazomethane hydrolysis exhibits a pH-independent section in the lower pH range, 8–10, with a downward break at higher pH, as has been reported for slightly different reaction conditions. In the case of diazoethane and 1-diazopropane, the reaction remains pH independent up to pH > 13. General acid catalysis of the hydrolysis reactions of diazomethane and diazoethane were examined in the pH-independent regions. For a limited number of catalysts, the value of Bronsted α was 0.58 for both diazoalkanes. The downward break in the pH rate profile for diazomethane hydrolysis is consistent with what was previously concluded, rate-limiting protonation by H2O in the pH-independent region changing to rate-limiting attack of water on the diazonium ion in the pH-dependent region, the decrease in rate constant with increasing pH being attributed to deprotonation of the diazonium ion by hydroxide ion. The lack of a downward break in the pH–rate profiles for hydrolysis of the diazoethane and 1-diazopropane is attributed specifically to the increase, relative to the methyldiazonium ion, in the rate constant for water attack on the ethyl- and 1-propyldiazonium ions, perhaps by as much as >103-fold. Copyright © 2004 John Wiley & Sons, Ltd.

To assess the effects of tiotropium on lung mucociliary clearance in COPD.Randomized, double-blind, placebo-controlled, parallel-group study.Outpatients of an urban-area university teaching hospital.Thirty-four patients with COPD aged 40 to 75 years classified equally into two groups.Single (18 microg) daily dose of tiotropium inhalation capsules or of placebo for 21 days.Six-hour tracheobronchial clearance of inhaled 99mTc-labeled polystyrene particles using a 48-h retention measurement to determine the "nontracheobronchial" deposition fraction.Test radioaerosol penetration into the lungs increased significantly (p0.003) as did FEV1 (p0.006) in the tiotropium-treated patients, but measured mucociliary clearance was not significantly changed despite the increased pathway length for clearance (mean +/- SE area under the tracheobronchial retention curve changed from 442 +/- 22 to 453 +/- 20%/h). Smaller (nonsignificant) decreases of radioaerosol penetration and FEV1 occurred in the placebo group together with a small (nonsignificant) decrease in the area under the retention curve.Twenty-one days of inhaled tiotropium, 18 microg/d, as a dry powder does not retard mucus clearance from the lungs.

One hundred thirty-six perennial rye-grass silages with wide variations in quality were evaluated for N and DM degradability in three beef steers offered grass silage of medium quality ad libitum. The silages were incubated in the rumen of each animal in triplicate for 0, 6, 12, 24, 48, and 72 h, respectively. The disappearance rates of N or DM were used to calculate the readily soluble fraction ("a" value), potentially degradable fraction ("b" value), and the fractional degradation rate of"b" ("c" value). The effective degradability (P) of N or DM was then estimated assuming a ruminal outflow rate of 0.02, 0.05, or 0.08/h (P0.02, P0.05, or P0.08). The objective was to use these data to develop prediction equations for N and DM degradability in grass silages. There were considerable variations in "a," "b," and "c" values and the P0.02, P0.05, or P0.08 of N and DM (e.g., the P0.02 of N ranged from 75.0 to 93.4% and the P0.02 of DM from 51.5 to 82.5%). The P0.02, P0.05, or P0.08 of N and DM were negatively related (P < 0.001) to ADF, NDF, and lignin concentrations but positively related (P < 0.001) to protein fractions (CP, soluble CP, and true protein concentrations) and digestibility of DM, OM, GE, CP, and NDF and digestible OM in the total DM (measured with sheep). The N and DM degradability data were also positively related to silage lactic acid concentration, but the relationships between DM degradability data and pH, ammonia N/total N, and VFA concentration in silages were negative (P < 0.05). Several sets of prediction equations (linear and multiple) were thus developed for N and DM degradability using CP or NDF concentration, "a" value or digestibility data as primary predictors, together with or without other nutrient concentration and silage fermentation variables. All these relationships were highly significant (P < 0.001), and each predictor had a significant effect on the relationship (P < 0.05). The R2 values in multiple regression for N and DM degradability were generally over 0.70 and higher than in linear regression equations. Four equations were also developed to convert N and DM degradability at a given ruminal outflow rate, predicted using the above-mentioned equations, to their counterparts at any ruminal outflow rate (0.02 to 0.10/h), respectively.

Grass silages (n = 136) were selected from commercial farms across Northern Ireland according to their pH, ammonia nitrogen, DM, and predicted ME concentration. Each silage was offered to four sheep as a sole feed at maintenance feeding level to determine nutrient digestibility and urinary energy output. Dry matter concentration was determined as alcohol-corrected toluene DM and was subsequently used as the basis for all nutrient concentrations. The objectives were to use these data to examine relationships between nutritive value and nutrient concentration or fermentation characteristics in silages and then develop prediction equations for silage nutritive values using stepwise multiple regression techniques. The silages had a large range in quality (DM = 15.5 to 41.3%, ME = 7.7 to 12.9 MJ/kg of DM, pH = 3.5 to 5.5) and a relatively even distribution over the range. There was a positive relationship (P < 0.001) between silage GE and DE or ME concentration. Digestible OM in total DM (DOMD); ME/GE; and digestibility of DM, OM, and GE were positively related (P < 0.05) to CP, soluble CP, ether extract, lactic acid concentration, and lactic acid/ total VFA, whereas they were negatively related (P < 0.05) to ADF, NDF, lignin, individual VFA concentration, pH, and ammonia N/total N. Concentrations of DE and ME and digestibility of CP and NDF had similar relationships with those variables, although some relationships were not significant. Three sets of multiple prediction equations for DE and ME concentration; ME/ GE; DOMD; and digestibility of DM, OM, GE, CP, and NDF were therefore developed using three sets of predictors. The first set included GE, CP, soluble N/total N, DM, ash, NDF, lignin, lactic acid/total VFA, and ammonia N/total N; the second set excluded soluble N/ total N and lignin because they are not typically measured; the third set further excluded the fermentation data. The R2 values generally decreased with exclusion of predictors. The second and third sets of equations, except for NDF digestibility, were validated using the mean-square-prediction-error model and an independent grass silage data set published since 1977 (n = 17 [DM digestibility] to 28 [DOMD and OM digestibility]). The validation indicated that the equations developed in the present experiment could accurately predict DE and ME concentrations and DE/GE and ME/GE in grass silages.