D50 Values Research Articles

T40. Comparison of MScanFit MUNE and other parameters derived from the CMAPScan in ALS patients

The aim of this study was to analyse MScanFit MUNE, D50 and step% values elicited from the CMAP scan curves of thenar and hypothenar muscles in patients with amyotrophic lateral sclerosis (ALS) and healthy controls. Thirty-four ALS patients (31 definite, 1 probable and 2 possible, according to Awaji criteria) and 24 healthy controls were included. CMAP scan curves were recorded from both thenar and hypothenar muscles by applying 500 stimuli. Step% and D50 values were calculated semi-automatically and MScanFit MUNE was calculated by using the freeware version of Qtrac software. Mean MScanFit MUNE and D50 values were lower and step% values were higher significantly in patients (48.8, 25.0, 32.5 in thenar muscles and 66.5, 28.9, 17.0 in hypothenar muscles, respectively) as compared to healthy controls (112.5, 45.6, 4.0 in thenar muscles and 124.5, 46.6, 1.1 in hypothenar muscles; p < 0.001). Step% provided the best discrimination by ROC analysis (area under the curve was 0.904 for thenar and 0.923 for hypothenar muscles). MScanFit MUNE and step% were significantly more abnormal in the thenar as compared to hypothenar muscles. MScanFit MUNE values were correlated significantly with step% and D50 values in both muscle groups (Spearman’s rho, p < 0.001). Step% and MScanFit MUNE are parameters correlated with each other and they are sensitive tools in revealing the severities and the courses of the electrophysiological abnormalities in ALS.

An Alternative Method for Internal Stability Prediction of Gravelly Soil

Experimental observations have shown that geometric characteristics of the soil have significant impact on the internal stability. Due to the diversity of grain composition, the degree of correlation between geometric control variables and internal stability for different types of soil may not be the same. Based on the statistical information of 140 different soils collected from the literature, an alternative method is proposed to assess the internal stability of gravelly soil with the maximum grain size reaching 60 mm. According to the values of d90, all the 140 soils are first classified into three clusters through hierarchical clustering method. Average values of d90 for cluster I, II and III are 8.16 mm, 58.66 mm and 152.33 mm, respectively. Then, the experimental results are taken as dichotomous variable (0 refers to internally unstable and 1 refers to internally stable). Point-biserial correlation coefficient is introduced to measure the correlation between geometric control variables and internal stability of the soils. The results show that Cu (coefficient of uniformity) and (d15c/d85f)max of cluster II present the highest degree of correlation with internal stability of soils among the three clusters. Therefore, an assessing method is suggested which unites two control variables (Cu and (d15c/d85f)max) to identify the internal stability of gravelly soil, and the boundary of the method is proposed as well. At last, laboratory tests are carried out to assess the internal stability of 8 gravelly soil samples which were gathered locally. The proposed method, together with five commonly used criteria, is used for the prediction of internal stability. By comparing the predictive results with the test results, the reliability of the suggested method is verified.

Comparative analysis of niobium and vanadium carbide efficiency in the high energy mechanical milling of aluminum bronze alloy

Abstract This study aims to analyze the efficiency of niobium and vanadium carbides in the high energy mechanical milling of aluminum bronze alloy. Two series of experiments were made following the same steps for both niobium carbide (NbC) and vanadium carbide (VC) additions: 30 g of chips were weighed and placed in a stainless steel jar with 3 % of carbide and 1 % of stearic acid for a mass/sphere relationship of 1:10. The milling was realized using a planetary ball mill for 10, 30 and 50 hours in an inert argon atmosphere at 300 rpm. Results shown in laser diffraction indicate a great reduction in the particle sizes of powders when VC is used. For 30 hours milling, D50 values ranged from 1580 µm with NbC to 182.3 µm with VC addition. The D50 values ranged from 251.5 µm with NbC to 52.26 µm with VC addition, for 50 hours milling. The scanning electron microscopy showed that in 10 hours of milling, the energy was not sufficient to achieve the shear of chips in both cases. For 30 hours, it's possible to observe particles with sizes between 100 µm and 800 µm with NbC addition while for the same milling time, with VC it's possible to see particles with different sizes, but with many shapes of fine particulates. For 50 hours milling, particles achieved the smaller sizes between 50 and 200 µm with NbC and ranging from 5 until 50 µm with VC addition.

Physicochemical properties of jet milled wheat flours and doughs

The aim of this study was to evaluate the physicochemical properties of white wheat flour pulverized by jet mill and the rheological behavior of the resultant doughs. A commercial coarse (control) wheat flour with d50 < 75 μm (CON) was micronized by jet-mill under two different feed rates, resulting in fine and ultrafine flour preparations with d50 < 21 μm (JM1) and d50 < 12 μm (JM2), respectively; d50 value was reduced with decreasing feed rate. The levels of damaged starch (5.3–11.5% as is) and water soluble arabinoxylans (0.4–0.5% d.b.) increased (p < 0.05) with reduction of flour particle size, while no changes in apparent peak molecular weight, determined by HPSEC–RI, and primary structure of the AXs (e.g. degree of branching) estimated by 1H NMR, were noted upon flour jet-milling. Starch gelatinization properties and dough rheological behavior of CON, JM1, JM2 flours and a mixture (CON:JM1 1:1), covering a particle size range applicable to actual breadmaking processes, were studied. Calorimetry of aqueous flour dispersions (flour:water 30:70 w/w) showed a decrease in starch gelatinization enthalpy of the flours containing jet mill fractions compared to control flour. For the jet mill flours, the creep-recovery test of doughs (flour:water 56:44) revealed an increase (p < 0.05) in resistance to deformation, elasticity and zero shear rate viscosity. Additionally, Texture Profile Analysis (TPA) and compression - stress relaxation testing after lubricated squeezing flow (LSF) revealed that with decreasing flour particle size, the doughs become harder with higher consistency, more sticky and gummy and exhibit longer half relaxation time, lower relaxation rate and higher elongational viscosity.

Use of volumetric modulated arc radiotherapy in patients with early stage glottic cancer.

We compared conformal, intensity-modulated radiotherapy (IMRT) and intensity-modulated arc therapy (IMAT) in early stage glottic cancer in terms of dosimetric features as target coverage, dose to the organs at risk and total treatment time. Five consecutive T1 glottic squamous cell carcinoma patients were selected for the study. Three-dimensional conformal radiotherapy (3D-CRT), 3-field or 5-field intensity-modulated radiotherapy (3F-IMRT and 5F-IMRT), or IMAT, which was in 2 different forms--a regular IMAT (R-IMAT) and an alternative IMAT (A-IMAT) with an unirradiated section, was planned for each patient. The prescribed dose was 63 Gy in 28 fractions. The minimum dose for 95% of the clinical target volume (D95), maximum dose point at clinical target volume (Dmax), total monitor units, left and right carotid artery doses (V35 and V50 - percentage of volume receiving 35 Gy and 50 Gy), and total treatment time were calculated for each plan. Median D95 values in the 5 plans studied with each technique ranged between 63 and 63.3 Gy (P = NS). Median Dmax values for each technique ranged between 65.4 and 70.8 Gy. The number of hot spots with IMRT and IMAT was significantly higher than with 3D-CRT plans. Conformal radiotherapy plans median V35 (93.6%) and V50 (76.6-83.3%) values for carotid arteries were significantly higher than with IMRT and IMAT (2.9%-11.4% and 0.0%). Average treatment times for 3D-CRT, 3F-IMRT, 5F-IMRT, R-IMAT and A-IMAT techniques were calculated as 64, 119, 147, 39 and 32 seconds, respectively. IMAT has significantly decreased the treatment time compared to IMRT and 3D-CRT with acceptable homogeneous clinical target volume coverage and low carotid dose.

Resection Cavity Contraction Effects in the Use of Radioactive Sources (1-25 versus Cs-131) for Intra-Operative Brain Implants&#x0D;

Background and ObjectivesIntra-parenchymal brain surgical resection cavities usually contract in volume following low dose rate (LDR) brachytherapy implants. In this study, we systematically modeled and assessed dose variability resulting from such changes for I-125 versus Cs-131 radioactive sources.MethodsResection cavity contraction was modeled based on 95 consecutive patient cases, using surveillance magnetic resonance (MR) images. The model was derived for single point source geometry and then fully simulated in 3D where I-125 or Cs-131 seeds were placed on the surface of an ellipsoidal resection cavity. Dose distribution estimated via TG-43 calculations and biological effective dose (BED) calculations were compared for both I-125 and Cs-131, accounting for resection cavity contractions.ResultsResection cavity volumes were found to contract with an effective half-life of approximately 3.4 months (time to reach 50% of maximum volume contraction). As a result, significant differences in dose distributions were noted between I-125 and Cs-131 radioactive sources. For example, when comparing with static volume, assuming no contraction effect, I-125 exhibited a 31.8% and 30.5% increase in D90 and D10 values (i.e., the minimal dose to 90% and 10% of the volume respectively) in the peripheral target areas over the follow-up period of 20.5 months. In contrast, Cs-131 seeds only exhibited a 1.44% and 0.64% increase in D90 and D10 values respectively. Such discrepancy is likewise similar for BED calculations.ConclusionResection cavity contractions affects Cs-131 dose distribution significantly less than that of I-125 for permanent brain implants. Care must be taken to account for cavity contractions when prescribing accumulative doses of a radioactive source in performing the brain implant procedures.

Dosimetric analysis of CT-guided salvage interstitial brachytherapy for recurrent cervical cancer

Objective To analyze the dosimetric advantages of CT-guided interstitial brachytherapy for recurrent cervical cancer. Methods A total of 16 patients with recurrent cervical cancer after radical surgery and adjuvant external beam radiotherapy received interstitial brachytherapy with CT-guided implantation of metal needles. The high-risk clinical target volume (HR-CTV) was given 36 Gy in 6 fractions. D90 for HR-CTV in the brachytherapy and the cumulative D2 cm3 values for the bladder, rectum, and sigmoid colon in the previous external beam radiotherapy and the brachytherapy were analyzed. Results The mean D90 value for HR-CTV was 52.5±3.3 Gy. The cumulative D2 cm3 values for the bladder, rectum, and sigmoid colon were 85.6±5.8 Gy, 71.6±6.4 Gy, and 69.6±5.9 Gy, respectively. The mean number of metal needles was 6.1±1.5 in each brachytherapy. The actual 1-year overall survival and local control were 81% and 69%, respectively. Conclusions CT-guided interstitial brachytherapy for recurrent cervical cancer shows good dose-volume histogram parameters and few complications, so it may be clinically feasible. However, its long-term clinical efficacy needs further observation. Key words: Cervical neoplasms/interstitial brachytherapy; Dosimetry

Flow resistance in gravel bed open channel flows case: intense transport condition

Gravel bed can be categorised into three bed load conditions, i.e. no load, moderate and intense. An experimental investigation was carried out in an open channel flow with gravel bed surface of grain size of D50 values 6.5 mm intense load conditions. The investigation of the roughness characteristics of gravel bed open channel flows under intense load conditions over various discharges and flow depths are presented. Variation of friction factor for the roughness conditions for different flow depths is estimated. The intensity of the bed load is calculated with the help of sediment transport rate. The bed load transport rate for the intense load conditions is also determined from experimentation on gravel beds of 6.5 mm gravel size for different flow depths. Using the data-set of other researchers and present experimental data, a new model as a function of intensity of the bed load transport with respect to Shield’s parameter is formulated. The modified model gives satisfactory results as compared to previous works, which is displayed through error analysis.

Who Really Benefits from 3D-Based Planning of Brachytherapy for Cervical Cancer?

BackgroundAlthough intracavitary radiotherapy (ICR) is essential for the radiation therapy of cervical cancer, few institutions in Korea perform 3-dimensional (3D)-based ICR. To identify patients who would benefit from 3D-based ICR, dosimetric parameters for tumor targets and organs at risk (OARs) were compared between 2-dimensional (2D)- and 3D-based ICR.MethodsTwenty patients with locally advanced cervical cancer who underwent external beam radiation therapy (EBRT) following 3D-based ICR were retrospectively evaluated. New 2D-based plans based on the Manchester system were developed. Tumor size was measured by magnetic resonance imaging.ResultsThe mean high risk clinical target volume (HR-CTV) D90 value was about 10% lower for 2D- than for 3D-based plans (88.4% vs. 97.7%; P = 0.068). Tumor coverage did not differ between 2D- and 3D-based plans in patients with tumors ≤ 4 cm at the time of brachytherapy, but the mean HR-CTV D90 values in patients with tumors > 4 cm were significantly higher for 3D-based plans than for 2D-based plans (96.0% vs. 78.1%; P = 0.017). Similar results were found for patients with tumors > 5 cm initially. Other dosimetric parameters for OARs were similar between 2D- and 3D-based plans, except that mean sigmoid D2cc was higher for 2D- than for 3D-based plans (67.5% vs. 58.8%; P = 0.043).ConclusionThese findings indicate that 3D-based ICR plans improve tumor coverage while satisfying the dose constraints for OARs. 3D-based ICR should be considered in patients with tumors > 4 cm size at the time of brachytherapy or > 5 cm initially.

Dosimetric Comparison between Bone and Target Matching Considering Interfractional Prostate Motion in Volumetric Modulated Arc Therapy

Adequate matching methods are critical for accurate volumetric-modulated arc therapy (VMAT). We investigated the dosimetric differences in the target and organs at risk (OARs) between bone matching and target matching in patients with prostate cancer treated with VMAT. The relationship between the dosimetric differences and interfractional motion of the prostate was also evaluated. Forty patients with prostate cancer classified as intermediate risk were enrolled in a study to assess the differences in dosimetry between two matching methods. These patients were treated with VMAT and prescribed dose was 78 Gy. The dose distribution was calculated using cone-beam computed tomography (CBCT) for this study. We selected clinical target volume (CTV) as the target, and the rectum and bladder as the OARs. The Dmean, D98, D95, and D2 to the target and V10-V70 to the OARs were calculated as different dose from target matching value minus bone matching value. Multiple regression analysis was used to evaluate the effect of interfractional motion of the prostate on the differences in dose. The CTV D95 values differed by -0.22 ± 1.01 Gy (mean ± standard deviation). Rectum and bladder V70 values differed by 4.6% ± 7.2% and -2.6% ± 7.2%, respectively. There was a correlation between interfractional motion of the prostate and the dose differences to OARs (R2 = 0.73 - 0.94). The dose differences to OARs also varied depending on the direction of the prostate’s motion. We found that bone matching resulted in an increased rectal dose and high risk of decreasing dose to the CTV.

Dosimetric and clinical effects of interfraction and intrafraction correlation errors during marker-based real-time tumor tracking for liver SBRT.

Correlation model error (CME) between the internal target and the external surrogate, and marker–tumor correlation error (MTCE) between the tumor and the implanted marker occur during marker-based real-time tumor tracking. The effects of these intrafraction and interfraction errors on the dose coverage in the clinical target volume (CTV) and on tumor control probability (TCP) for hepatocellular carcinoma (HCC) were evaluated in this study. Eight HCC patients treated with non-isocentric dose delivery by a robotic radiosurgery system were enrolled. The CMEs were extracted from the treatment log file, and the MTCEs were calculated from the preceding study. The CMEs and MTCEs were randomly added to each beam’s robot position, and the changes in the TCP and the 2%, 95% and 99% dose coverage values for the CTV (D2, D95 and D99) were simulated. The data were statistically analyzed as a function of the CTV to planning target volume (PTV) margin, the dose fraction and the marker–tumor distance. Significant differences were observed in the majority of the CTV D2, D95 and D99 values and the TCP values. However, a linear regression revealed that ∆CTV D2, D95 and D99 have a weak correlation with ∆TCP. A dose-difference metric would be unable to detect a critical error for tumor control if the coverage changes for the CTV and ∆TCP were weakly correlated. Because the simulated TCP-based parameter determination was based on the dose simulation, including predicted interfraction and intrafraction errors, we concluded that a 95th percentile TCP-based parameter determination would be a robust strategy for ensuring tumor control while reducing doses to normal structures.

PARTICLE SIZE DISTRIBUTION OF NANOSCALE ULEXITE MINERAL PREPARED BY BALL MILLING

Commercially available raw ulexite (U) minerals were milled up to 120 min by using a high-energy ball grinder for different initial feed sizes (−75 µm and −3 mm), ball to powder ratios (5:1 and 10:1), ball sizes (1 mm and 5 mm), and process control agents (3% and 6%). Particle size distribution and morphology measurements of milled powders were carefully studied. In particle size analysis, the lowest d90, d50, d10 and dmin values were detected to be 17.547 µm, 1.732 µm, 283 nm and 35 nm, respectively. Therefore, nanoscale in particle size for the ulexite mineral has been achieved. In addition, the smallest milling time was found as 30 min. Moreover, the best powder yield was determined to be 90.5%. In morphology analysis, the milled powders were observed to be more homogeneous than the initial feed size minerals. Besides, findings of morphology analysis were in agreement with that of particle size analysis. It was decided that optimized ball milling parameters are −3 mm for initial feed size; 10:1 for the ball to powder ratio; 5 mm for ball size; 3% for process control agent. The results obtained from this work will be useful for nanoscale research and industrial applications of ulexite (Na2O.2CaO.5B2O3.16H2O) material, which is boron mineral. Article DOI: https://dx.doi.org/10.20319/mijst.2017.33.86103 This work is licensed under the Creative Commons Attribution-Non-commercial 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.

Continuous, dynamic and steady state simulation of the reflux classifier using a segregation-dispersion model

A 2D continuous segregation-dispersion model incorporating a laminar- shear separation mechanism has been developed to describe the Reflux Classifier (RC). The RC, which consists of a fluidization zone, and a system of closely-spaced inclined channels, is now widely used to achieve gravity separation of a broad range of commodities. The narrow inclined channels promote the laminar-shear mechanism, leading to the selective shear-induced lift of low density particles, while allowing the fine and denser particles to deposit onto the inclined surfaces, and slide downwards. This mechanism allows a sharp density-based separation. The simulation results of this study have been validated using previously published experimental data. A total of 42 particle species were used in the simulations, corresponding to 6 different sizes and 7 different densities for each particle size, covering the particle size range of −2.0+0.125 mm. Simulation partition curves showed good agreement with the published experimental data, including the D50 and Ep values over the particle size range −2.0+0.25 mm. The model has also been tested to investigate the effect of high solid throughputs on the separation performance in the RC. The predictions of the fractional and cumulative ash % of the product and reject streams have been compared with the published experimental results demonstrating a good agreement and thus, the robustness of the model.

Developing strategies to reduce spray drift in pneumatic spraying in vineyards: Assessment of the parameters affecting droplet size in pneumatic spraying

Pneumatic sprayers are widely used in vineyards due to their very fine droplet size, which makes the drift risk to become an important problem to be considered. The aim of this study was to assess the effect of the spout diameter at the release point on the spray droplet size and uniformity achieved for different liquid flow rates (LFR) and air flow rates (AFR).A test bench was developed to simulate a real pneumatic sprayer under laboratory conditions, and it was empirically adjusted to match the air pressure conditions as closely as possible to real working conditions. Two positions of insertion of the liquid hose, the conventional position (CP) and an alternative position (AP), were tested for three LFRs, 1.00, 1.64, and 2.67Lmin−1, and four AFRs, 0.280, 0.312, 0.345, and 0.376m3s−1. The air speed decrease between the two insertion points of the liquid hose was measured. A Malvern SprayTec® instrument was used to measure the droplet size, and the D50, D10, and D90 parameter values were obtained. The relative SPAN factor (RSF) was also calculated. A model to predict variations in D50 was fitted using the aforementioned parameters.The results show that variations in the diameter of the spout significantly change the droplet size, producing a mean increase of 59.45% in D50 and similar increases in D10 and D90. The model developed to predict variations in D50 has a very high degree of accuracy (R2=0.945). The relative decrease in the air speed along the spout did not present significant differences for the different airflow rates tested. The results of the study show that the droplet size produced in pneumatic spraying can be modified easily by varying the air spout dimensions. This should be taken into account by manufacturers from a design point of view.

Delineating the relationship between Point A prescription dose and pelvic lymph node doses in intracavitary high-dose-rate brachytherapy treatment of cervical cancer for use in low- and middle-income countries

PurposeTo define the relationship between the Point A prescription dose and the dose delivered to various pelvic lymph node groups during high-dose-rate (HDR) brachytherapy treatment of cervical cancer. In less developed countries, brachytherapy is often done without three-dimensional image guidance, instead relying on plain radiography and prescription to Point A. A defined relationship between Point A dose and lymph node doses would help physicians in these health care settings to more accurately estimate nodal doses. Methods AND MATERIALSTreatment data from 50 fractions of HDR brachytherapy of cervical cancer were reviewed, the pelvic lymph nodes were contoured, and dose–volume histogram parameters were obtained. Dose–volume histogram parameters for each contour were normalized as a percentage of the corresponding Point A dose. All nodal groups were divided into left and right sides, except the presacral nodal group. Results AND CONCLUSIONSMean Point A doses were bilateral (Bil) 5.92 Gy ± 0.58, left (L) 5.93 ± 0.59, and right (R) 5.92 ± 0.59. Mean normalized D90 values for the various lymph node groups were as follows—obturator: Bil 20.3% ± 4.5, L 20.5% ± 4.4, and R 20.2% ± 5.2; external iliac: Bil 9.5% ± 2.9, L 10.0% ± 3.1, and R 9.5% ± 3.0; internal iliac: Bil 12.2% ± 3.5, L 12.1% ± 3.4, and R 12.9% ± 4.7; common iliac: Bil 4.3% ± 1.6, L 4.3% ± 1.6, and R 4.3% ± 1.7; and presacral: 8.7% ± 3.4. These relationships can serve as a useful tool for evaluating lymph node doses during HDR brachytherapy of cervical cancer in facilities performing two-dimensional treatment planning and those with limited resources.

Patterns of Dose Prescription and Recording in Stereotactic Body Radiation Therapy: A Multi-institutional Study

Hypofractionated stereotactic body radiation therapy (SBRT) has become standard of care for small inoperable lesions in many disease sites. Dose prescription and delivery play an important role; however there is no consistent way of reporting dose and treatment outcome (1). This study evaluates the variability in dose prescription and reporting among academic institutions. The SBRT data of 428 patients from 8 academic institutions were collected. Prescription and delivery parameters were examined such as treatment site, technique (3DCRT, IMRT, VMAT, etc.), treatment planning system, inhomogeneity correction algorithm, dose prescription, size of target volume, normalization and monitor unit (MU). The dose-volume histogram (DVH) for each patient was anonymously analyzed at a central location following international guidelines, ICRU-50 and ICRU-83 for 3DCRT and IMRT, respectively. Dose parameters; D100, D98, D95, D50, D2 were extracted for analysis of SBRT plan and variability among institutions. Use of 3DCRT, IMRT and VMAT was 12%, 31%, and 57%, respectively. Surprisingly every institution used same treatment planning and algorithm for dose calculation. Disease sites were mainly lung (71%) followed by liver (15.5%), prostate (7.5%), spine (6.8%), brain (4.1%), and pancreas (2.5%). Target volume in lung cases varied and largely fell into two groups (22.0-28.7) and (48.0-67.1) cm3 indicating differences in margin or selection of larger tumors. The MU was inversely proportion to the treatment volume. A hot spot ranging from 120-150% was noted in nearly half of the patients and was more specific to some institutions. A D50 ≥110% was found in nearly half of the institutions. Three of the four institutions that delivered D50 values <110% still had a difference between D50 and D98 of ≥10%, suggesting the relative dose distributions among these 3 institutions was similar in general to that of the other four with high D50 values. These same seven institutions had relatively high inhomogeneity index (HI) as summarized in Table 1. As shown by the large variation in dosimetry among academic institutions, a single dose parameter to characterize SBRT prescriptions in the literature or in guidelines can be very misleading. Large variation in volume indicates larger margin characteristics of institutional practice. An attempt to unify dose prescription and delivery is needed for outcome comparison as we move towards more hypofractionated treatments.

Possible threshold controls on sediment grain properties of Peruvian coastal river basins

Abstract. To determine possible controls on sediment grain properties, 21 coastal rivers located along the entire western Peruvian margin were analysed. This represents one of the largest grain size dataset that has been collected over a large area. Modern gravel beds were sampled along a north–south transect on the western side of the Peruvian Andes where the rivers cross the tip of the mountain range, and at each site the long a axis and the intermediate b axis of about 500 pebbles were measured. Morphometric properties of each drainage basin, sediment and water discharge, together with flow shear stresses, were determined and compared against measured grain properties. Pebble size data show that the values for the D50 are nearly constant and range between 2 and 3 cm, while the values of the D96 range between 6 and 12 cm. The ratios between the intermediate and the long axis range from 0.67 to 0.74. Linear correlations between all grain size percentiles and water shear stresses, mean basin denudation rates, mean basin slopes and basin sizes are small to non-existent. However, exceptionally large D50 values of 4–6 cm were measured for basins situated between 11–12 and 16–17° S latitude where hillslope gradients are steeper than on average or where mean annual stream flows exceed the average values of the western Peruvian streams by a factor of 2. We suggest that the generally uniform grain size pattern has been perturbed where either mean basin slopes or water fluxes exceed threshold conditions.

O100 CMAP scan in diagnosis and follow-up of patients with amyotrophic lateral sclerosis

Objective Compound muscle action potential scanning (CMAP scan) is a non-invasive electrophysiological tool that allows observation of the whole-range of the functional motor unites in a muscle. The objective of this study is to assess the changes in CMAP scan from abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles during the diagnosis and follow up period in amyotrophic lateral sclerosis (ALS) patients. Method Seventeen patients with ALS and 15 healthy controls (HCs), were included in the study. Five hundred stimuli were applied with equal steps in descending order at 2 Hz, in order to generate a CMAP scan curve. The data were exported to Microsoft Excel 2007. Backward step% step%, gap%, D50 were calculated. Results Backward step% step%, gap%, D50 values for ADM muscle were 264, 22.6, 27.9, 23.4 in ALS and 179.3, 1.9, 1.8, 46.7 in the control group, respectively (p ⩽ 0.05, between ALS and HC groups). Backward step% step%, gap%, D50 values for APB muscle were 500.6, 41.3, 39.9, 20.5 for ALS group and 241.7, 3.6, 3, 46.4 for the control group (p ⩽ 0.05, between ALS and HC groups). In ALS patients, backward step%, step%, gap% were found to be more severely affected in APB muscle. Follow-up studies of 6 patients showed significant difference in step%, gap% in APB muscle and D50, step% in ADM muscle. Conclusion CMAP scan is a sensitive electrophysiological method for showing the motor unit changes caused by ALS and for observing the effects of split-hand phenomenon.

Novel amino acid‐based surfactant for silicone emulsification and its application in hair care products: a promising alternative to quaternary ammonium cationic surfactants

Quaternary ammonium cationic surfactants (ACSs) and N-[3-alkyl(12,14)oxy-2-hydroxypropyl]-l-arginine hydrochloride (N-AOHPA) were used to emulsify silicone. The potential of the resulting emulsions in hair conditioning products was investigated. The emulsions were prepared using a homogenizer and/or high-pressure homogenizer. ACSs and N-AOHPA were used as silicone emulsifiers. The stability of the emulsions was evaluated by measuring particle sizes, creaming fractions, polydispersity indexes and zeta potentials. Moreover, the N-AOHPA-stabilized emulsion was compared with the ACS-stabilized emulsion to evaluate the adsorption amount of silicone on healthy and bleached hair surfaces and the inhibitory effects on amino acid dissolution from bleached hair. The adsorption site of the N-AOHPA-stabilized emulsion was observed using a scanning electron microscope. For all surfactants, the silicone emulsions prepared using the high-pressure homogenizer were more stable than those prepared using the homogenizer. When N-AOHPA was used as the surfactant, the silicone emulsion was especially stable. Furthermore, the d50 value of the N-AOHPA-stabilized emulsion was smaller than that of the ACS-stabilized emulsion. The adsorption behaviour of the silicone droplets in the different emulsions varied depending on the nature of the surfactant and the preparation method. The amount of ACS-stabilized silicone adsorbed on healthy hair was higher than that adsorbed on bleached hair, especially when the emulsion was prepared using the homogenizer. In contrast, the amount of N-AOHPA-stabilized silicone adsorbed on bleached hair was high, and no differences were observed between the N-AOHPA-stabilized emulsions prepared using the homogenizer and high-pressure homogenizer. The emulsified droplets, especially the N-AOHPA-stabilized droplets prepared using the high-pressure homogenizer, prevented amino acid dissolution from bleached hair. It was concluded that the silicone droplet adsorption site affected the dissolution process because the small N-AOHPA-stabilized droplets adsorbed at cuticle edges. This study shows that N-AOHPA has good potential for use as an emulsifier in products used for improving the condition of damaged hair.

Individualized 4-dimensional computed tomography proton treatment for pancreatic tumors.

The goal of this study is to determine whether a phase or reconstruction of a 10-phase 4 dimensional computed tomography (4D CT) scan can be used as the primary planning scan for proton treatment of the pancreas, thus eliminating the need for second a slow CT or free breathing CT. Ten patients with pancreatic adenocarcinoma were simulated with 4D CT and a proton treatment plan generated based upon one of three primary planning scans, the T0 phase, T50 phase or average reconstruction. These plans were then exported to each of the remaining phases of the 4D CT and the dose to 95% of the target (D95) calculated. Plans were deemed adequate if the D95 remained at 99% of the prescribed dose or greater. For the ten patients in this study anterior abdominal motion was found to range from 2-27 mm (mean 7.50±6.79 mm). For 9 of 10 patients the anterior abdominal motion was ≤8 mm and all three primary planning scans provided adequate target coverage, resulting in minimum D95 coverage per plan of T0_plan 99.7%, T50_plan 99.3% and AVE_plan 99%. However no plan provided adequate target coverage on the single patient with the largest anterior abdominal motion, 27 mm, and cranio-caudal motion, 20 mm, with minimum D95 values of T0_plan 96.3%, T50_plan 68%, and AVE_plan 68%. The primary plans tested based up on the T0, T50 and average reconstructions provided adequate D95 coverage throughout the respiratory cycle as long as the anterior abdominal motion was ≤8 mm and can be considered for use as the primary proton planning scan.