Analysis on frosting of heat exchanger and numerical simulation of heat transfer characteristics using BP neural network learning algorithm.

The study is aimed at the frosting problem of the air source heat pump in the low temperature and high humidity environment, which reduces the service life of the system. First, the frosting characteristics at the evaporator side of the air source heat pump system are analyzed. Then, a new defrost technology is proposed, and dimensional theory and neural network are combined to predict the transfer performance of the new system. Finally, an adaptive network control algorithm is proposed to predict the frosting amount. This algorithm optimizes the traditional neural network algorithm control process, and it is more flexible, objective, and reliable in the selection of the hidden layer, the acquisition of the optimal function, and the selection of the corresponding learning rate. Through model performance, regression analysis, and heat transfer characteristics simulation, the effectiveness of this method is further confirmed. It is found that, the new air source heat pump defrost system can provide auxiliary heat, effectively regulating the temperature and humidity. The mean square error is 0.019827, and the heat pump can operate efficiently under frosting conditions. The defrost system is easy to operate, and facilitates manufactures designing for different regions under different conditions. This research provides reference for energy conservation, emission reduction, and sustainable economic development.

Comparison of two electronic hand hygiene monitoring systems in promoting hand hygiene of healthcare workers in the intensive care unit.

BACKGROUND: Hand hygiene (HH) is the cornerstone of infection control, and the promotion of HH is the focus of the world. The study aims to compare the role of two different types of electronic hand hygiene monitoring systems (EHHMSs) in promoting HH of healthcare workers (HCWs) in the intensive care unit (ICU). METHODS: In a 16-bed ICU of a general tertiary hospital in Shenzhen, the research was divided into three stages with interrupted time series (ITS) design. In the first stage, the direct observation method was used to monitor and feed back the HH compliance rate of HCWs monthly. In the second stage, the type1 EHHMS was applied to monitor and feed back the individual number of HH events monthly. In the third stage, the type2 EHHMS with a function of instant reminder and feedback was employed, and the personal HH compliance rates were fed back monthly. Meanwhile, direct observation continued in the last two stages. RESULTS: In the second stage, The HH compliance rate increased. However, there was no significant difference in the trajectory of the rate compared with the first stage. In the first month of the third stage, the HH compliance rate increased by 12.324% immediately and then ascended by 1.242% over time. The number of HH events per bed day and HH products' consumption per bed day were consistent with the change of HH compliance rate observed. CONCLUSION: Monitoring and feedback can improve the HH of HCWs. The EHHMS, with the function of real-time reminders and feedback, has a more noticeable effect on promoting HH.

Is mercury in fluorescent lamps the only risk to human health? A study of environmental mobility of toxic metals and human health risk assessment.

Although fluorescent lamps (FL) are extensively used worldwide, recycling rates in some countries are still low. If disposed of inappropriately and broken, FL can cause soil contamination. Hg toxicity in FL is extensively discussed in the literature; however, few studies address the other toxic metals present in the phosphorous powder of FL (PPFL). This paper presents a characterization of the environmental mobility with sequential extraction scheme (SES) of Cd, Cu, Hg, Mn, Ni, Pb, and Zn in PPFL, and modeling the potential risks to human health, in case of direct disposal in soils. An after thermal treatment waste was used for safety reasons. The SES method included five fractions, and the quantification was performed by flame atomic absorption spectrometry (FAAS). Human health risk assessment (HHRA) was conducted using RISC4® software. The PPFL showed the following mobility sequence: Cu (85%) > Ni (81%) > Hg (80%) > Zn (77%) > Cd (75%) > Mn (6%) > Pb (2%), which suggests that Cu, Ni, Zn, and Cd, besides Hg, could be of environmental concern in terms of availability. HHRA showed the potential hazard of Cd, for both children and adults, in the hypothetical scenario of vegetable ingestion, considering vegetables grown in soils contaminated with FL waste. The thermal treatment does not completely remove Hg from the matrix, and the residual Hg still poses a risk to children. These results show that Hg and Cd can be hazardous to humans and reinforce the importance of the correct disposal and treatment of PPFL.

A tri-hybrid method to estimate the patient-generated scattered photon fluence components to the EPID image plane.

In vivo dosimetry methods can verify the prescription dose is delivered to the patient during treatment. Unfortunately, in exit dosimetry, the megavoltage image is contaminated with patient-generated scattered photons. However, estimation and removal of the effect of this fluence improves accuracy of in vivo dosimetry methods. This work develops a 'tri-hybrid' algorithm combining analytical, Monte Carlo (MC) and pencil-beam scatter kernel methods to provide accurate estimates of the total patient-generated scattered photon fluence entering the MV imager. For the multiply-scattered photon fluence, a modified MC simulation method was applied, using only a few histories. From each second- and higher-order interaction site in the simulation, energy fluence entering all pixels of the imager was calculated using analytical methods. For photon fluence generated by electron interactions in the patient (i.e. bremsstrahlung and positron annihilation), a convolution/superposition approach was employed using pencil-beam scatter fluence kernels as a function of patient thickness and air gap distance, superposed on the incident fluence distribution. The total patient-scattered photon fluence entering the imager was compared with a corresponding full MC simulation (EGSnrc) for several test cases. These included three geometric phantoms (water, half-water/half-lung, computed tomography thorax) using monoenergetic (1.5, 5.5 and 12.5 MeV) and polyenergetic (6 and 18 MV) photon beams, 10 × 10 cm2 field, source-to-surface distance 100 cm, source-to-imager distance 150 cm and 40 × 40 cm2 imager. The proposed tri-hybrid method is demonstrated to agree well with full MC simulation, with the average fluence differences and standard deviations found to be within 0.5% and 1%, respectively, for test cases examined here. The method, as implemented here with a single CPU (non-parallelized), takes ∼80 s, which is considerably shorter compared to full MC simulation (∼30 h). This is a promising method for fast yet accurate calculation of patient-scattered fluence at the imaging plane for in vivo dosimetry applications.

Electronic pillbox-enabled self-administered therapy versus standard directly observed therapy for tuberculosis medication adherence and treatment outcomes in Ethiopia (SELFTB): protocol for a multicenter randomized controlled trial.

BACKGROUND: To address the multifaceted challenges associated with tuberculosis (TB) in-person directly observed therapy (DOT), the World Health Organization recently recommended that countries maximize the use of digital adherence technologies. Sub-Saharan Africa needs to investigate the effectiveness of such technologies in local contexts and proactively contribute to global decisions around patient-centered TB care. This study aims to evaluate the effectiveness of pillbox-enabled self-administered therapy (SAT) compared to standard DOT on adherence to TB medication and treatment outcomes in Ethiopia. It also aims to assess the usability, acceptability, and cost-effectiveness of the intervention from the patient and provider perspectives. METHODS: This is a multicenter, randomized, controlled, open-label, superiority, effectiveness-implementation hybrid, mixed-methods, two-arm trial. The study is designed to enroll 144 outpatients with new or previously treated, bacteriologically confirmed, drug-sensitive pulmonary TB who are eligible to start the standard 6-month first-line anti-TB regimen. Participants in the intervention arm (n = 72) will receive 15 days of HRZE-isoniazid, rifampicin, pyrazinamide, and ethambutol-fixed-dose combination therapy in the evriMED500 medication event reminder monitor device for self-administration. When returned, providers will count any remaining tablets in the device, download the pill-taking data, and refill based on preset criteria. Participants can consult the provider in cases of illness or adverse events outside of scheduled visits. Providers will handle participants in the control arm (n = 72) according to the standard in-person DOT. Both arms will be followed up throughout the 2-month intensive phase. The primary outcomes will be medication adherence and sputum conversion. Adherence to medication will be calculated as the proportion of patients who missed doses in the intervention (pill count) versus DOT (direct observation) arms, confirmed further by IsoScreen urine isoniazid test and a self-report of adherence on eight-item Morisky Medication Adherence Scale. Sputum conversion is defined as the proportion of patients with smear conversion following the intensive phase in intervention versus DOT arms, confirmed further by pre-post intensive phase BACTEC MGIT TB liquid culture. Pre-post treatment MGIT drug susceptibility testing will determine whether resistance to anti-TB drugs could have impacted culture conversion. Secondary outcomes will include other clinical outcomes (treatment not completed, death, or loss to follow-up), cost-effectiveness-individual and societal costs with quality-adjusted life years-and acceptability and usability of the intervention by patients and providers. DISCUSSION: This study will be the first in Ethiopia, and of the first three in sub-Saharan Africa, to determine whether electronic pillbox-enabled SAT improves adherence to TB medication and treatment outcomes, all without affecting the inherent dignity and economic wellbeing of patients with TB. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04216420. Registered on 2 January 2020.

Emotiv EPOC+ fed electrical muscle stimulation system; an inexpensive brain-computer interface for rehabilitation of neuro muscular disorders.

Advancements in the Neuro-rehabilitation across Pakistan is warranted to effectively and efficiently deal with the disease burden of neurological conditions. Being a developing country, an in-expensive treatment approach is required to culminate the rise in the disease occurrence in Pakistan. Brain-Computer Interfaces (BCIs) have come up as a new channel for communication and control, eliminating the need of physical input, opening doors to a wide array of applications in terms of assistive and rehabilitative devices for paralyzed patients and those with neuromuscular disorders. Even with a promising prospect, BCIs and electroencephalograms (EEG) can be very expensive and therefore, they are not practically applicable. For this reason, the purpose of the current study was to come up with a possibility of an inexpensive BCI for rehabilitation of patients with neuro-muscular disorders in Pakistan by using a low-cost and readily available equipment like Emotiv EPOC+ EEG headset and electrical muscle stimulator.

Supplier Selection and Order Allocation under a Carbon Emission Trading Scheme: A Case Study from China.

In implementing carbon emission trading schemes (ETSs), the cost of carbon embedded in raw materials further complicates supplier selection and order allocation. Firms have to make decisions by comprehensively considering the cost and the important intangible performance of suppliers. This paper uses an analytic network process-integer programming (ANP-IP) model based on a multiple-criteria decision-making (MCDM) approach to solve the above issues by first evaluating and then optimizing them. The carbon embedded in components, which can be used to reflect the carbon competitiveness of a supplier, is integrated into the ANP-IP model. In addition, an international large-scale electronic equipment manufacturer in China is used to validate the model. Different scenarios involving different carbon prices are designed to analyze whether China's current ETS drives firms to choose more low-carbon suppliers. The results show that current carbon constraints are not stringent enough to drive firms to select low-carbon suppliers. A more stringent ETS with a higher carbon price could facilitate the creation of a low-carbon supply chain. The analysis of the firm's total cost and of the total cost composition indicates that the impact of a more stringent ETS on the firm results mainly from indirect costs instead of direct costs. The indirect cost is caused by the suppliers' transfer of part of the low-carbon investment in the product, and arises from buying carbon permits with high carbon prices. Implications revealed by the model analysis are discussed to provide guidance to suppliers regarding the balance between soft competitiveness and low-carbon production capability and to provide guidance to the firm on how to cooperate with suppliers to achieve a mutually beneficial situation.

Effect of a Smart Pill Bottle and Pharmacist Intervention on Medication Adherence in Patients with Multiple Myeloma New to Lenalidomide Therapy.

BACKGROUND: U.S. specialty drug spend is expected to reach $400 billion by 2020, with significant growth in oncology. New oral oncology approvals have allowed for more convenient outpatient administration compared with physician-administered chemotherapies; however, patients may encounter challenges with adherence when taking medications at home. Emerging medication adherence technology (MAT) attempts to provide at-home adherence support, and while one such technology, smart pill bottles (SPB), claims to improve medication adherence, few studies have formally assessed their effects. OBJECTIVES: To assess the effect of an SPB with pharmacist intervention on medication adherence in adult patients with multiple myeloma (MM) new to lenalidomide therapy (≤ 5 cycle dispenses). Secondary objectives were to evaluate treatment cycles completed, evaluate the significance of real-time pharmacist engagement (intervention group only), determine the incremental cost-effectiveness ratio (ICER), and evaluate patient satisfaction and likelihood to use an SPB. METHODS: This prospective, random assignment, single-site, and single-blinded study recruited 40 adult patients diagnosed with MM new to lenalidomide at a specialty pharmacy. Recruitment was completed January-February 2016, and the length of study was 6 months. Participants were randomized 1:1 between the intervention and control groups. The intervention group received lenalidomide in activated SPBs with light, chimes, text message reminders, and pharmacist follow-up if weekly SPB adherence rates dropped below 80%. The control group received lenalidomide in identical SPBs with all alerts deactivated. SBPs contained cellular capabilities, enabling around-the-clock data transmission and captured data upon bottle-uncapping events. Patient adherence was calculated by dividing the number of bottle-uncapping events by the total number of doses supplied for each dosing cycle. Lenalidomide cycles completed and pharmacist outreach to the same patient were counted to determine pharmacist intervention. The ICER was calculated to determine SPB cost-effectiveness, and a Likert scale survey was given to the intervention group to evaluate patient satisfaction with the full-service SPB. RESULTS: Sixteen participants in each arm completed the study; 4 patients in each arm were lost to follow-up. Median adherence was improved for the intervention group compared with the control group (median = 100% vs. 87.4%; P = 0.001). The ICER per patient percentage adherence increase was found to be $96.03. Sixty percent of patients in the intervention group who responded to the post-satisfaction survey rated the full SPB service very positively. CONCLUSIONS: In this study, SPB interventions were associated with increased medication adherence and patient satisfaction. This pilot also provides empirical data on the cost-effectiveness of adherence technology used in a specialty pharmacy oncology setting. DISCLOSURES: This study was supported by Avella Specialty Pharmacy and AdhereTech. All authors are employees of Avella; Eric Sredzinski was an option holder of Avella; and none of the Avella authors had a financial interest in AdhereTech. AdhereTech provided the SPBs and data services for the duration of this study. The authors report no other potential conflicts of interest. Interim study data were presented at the 2016 Southwestern States Residency Conference (SSRC) on June 20, 2016, in Phoenix, AZ.

Technical Note: Accuracy of MTF measurements with an edge phantom at megavoltage x-ray energies.

PURPOSE: Measurement of the modulation transfer function (MTF) is performed by evaluating the response of an imaging system to a predefined input. To obtain accurate results when using an edge phantom, the detector input signal must resemble an ideal step function. The MTF of megavoltage (MV) imagers used in radiotherapy has been measured with highly absorbing edge phantoms fabricated from thick metal blocks. This study investigates the influence of the edge phantom design on the accuracy of the resulting MTF. METHODS: The MTF of an electronic portal imaging device (EPID) was measured at 6 MV beam quality with four edge phantoms made of lead with 1.3, 3.3, 5.0, and 10.0 cm thickness. Monte Carlo simulations were carried out for these and a selection of tungsten phantoms to determine the photon fluence at the imaging plane and quantify the systematic error in the MTF introduced by the edge phantom design. RESULTS: The measured MTF depends on the design of the edge phantom. The detector input signal of a thin phantom is affected by secondary radiation from the phantom itself, causing an overestimation of the MTF. The amount of secondary radiation can be reduced by increasing the phantom thickness or introducing an air gap between the phantom and the detector. Both methods introduce geometric unsharpness, which can result in an underestimation of the true MTF. Edge phantoms made from 4.0 cm thick tungsten or 5.0 cm thick lead induce comparatively small systematic errors of below 3% or 5%, respectively. CONCLUSIONS: When MTF measurements are conducted at MV energies, even a highly absorbing edge phantom will introduce a systematic error of several percent. Direct comparison of MTFs obtained with different edge phantoms should therefore be treated with caution.

6-MV small field output factors: intra-/intermachine comparison and implementation of TRS-483 using various detectors and several linear accelerators.

PURPOSE: To investigate the applicability of output correction factors reported in TRS-483 on 6-MV small-field detector-reading ratios using four solid-state detectors. Also, to investigate variations in 6-MV small-field output factors (OF) among nominally matched linear accelerators (linacs). METHODS: The TRS-483 Code of Practice (CoP) introduced and provided output correction factors to be applied to measured detector-reading ratios to obtain OFs for several small-field detectors. Detector readings for 0.5 cm × 0.5 cm to 8 cm × 8 cm fields were measured and normalized to that of 10 cm × 10 cm field giving the detector-reading ratios. Three silicon diodes, IBA PFD, IBA EFD (IBA, Schwarzenbruck, Germany), PTW T60017, and one microdiamond, PTW T60019 (PTW, Freiburg, Germany), were used. Output correction factors from the CoP were applied to measured detector-reading ratios. Measurements were performed on six Clinac and six TrueBeam linacs (Varian Medical Systems, Palo Alto, USA). An investigation of the relationship between the size of small fields and corresponding detector-reading ratio among the linacs was performed by measuring lateral dose profiles for 0.5 cm × 0.5 cm fields to determine the full width half maximum (FWHM). The relationship between the linacs' focal spot size and the small-field detector-reading ratio was investigated by measuring 10 cm × 10 cm lateral dose profiles and determining the penumbra width reflecting the focal spot size. Measurement geometry was as follows: gantry angle = 0°, collimator angle = 0°, source-to surface distance (SSD) = 90 cm, and depth in water = 10 cm. RESULTS: For a given linac and 0.5 cm × 0.5 cm field, the deviations in detector-reading ratios among the detectors were 9%-15% for the Clinacs and 4%-5% for the TrueBeams. Use of output correction factors reduced these deviations to 6%-12% and 3%-4%, respectively. For field sizes equal to or larger than 0.8 cm × 0.8 cm, the deviations were corrected to 1% using output correction factors for both Clinacs and TrueBeams. For a given detector and 0.5 cm × 0.5 cm field, the deviations in detector-reading ratios among the linacs were 11%-17% for the Clinacs and 5-6% for the TrueBeams. For 1 cm × 1 cm the deviations were 1%-2% for Clinacs and 1% for TrueBeams. For field sizes larger than 1 cm × 1 cm the deviations were within 1% for both Clinacs and TrueBeams. No relationship between FWHMs and detector-reading ratios for 0.5 cm × 0.5 cm was observed. For Clinacs, larger 10 cm × 10 cm penumbra width yielded lower 0.5 cm × 0.5 cm detector-reading ratio indicating an effect of the focal spot size. For TrueBeams, the spread of penumbra widths was lower compared to Clinacs and no similar relationship was observed. CONCLUSIONS: Output correction factors from the TRS-483 CoP are not sufficient for accurate determination of OF for 0.5 cm × 0.5 cm fields but are applicable for 0.8 cm × 0.8 cm to 8 cm × 8 cm fields. Nominally matched Clinacs and TrueBeams show large differences in detector-reading ratios for fields smaller than 1 cm × 1 cm.

An electronic tool to aid community pharmacists in optimizing care for persons with diabetes.

OBJECTIVE: To develop an electronic tool to aid community-based pharmacists in incorporating diabetes-specific clinical services into pharmacy workflow and to determine the utility of the tool. SETTING: Three independent community pharmacy locations. PRACTICE DESCRIPTION: Realo Discount Drugs is a group of 18 independent community pharmacies, a specialty pharmacy, and a long-term care pharmacy, all with a common owner, serving eastern North Carolina. PRACTICE INNOVATION: An electronic tool was developed to aid pharmacists in identifying gaps in therapy for patients with diabetes in alignment with the 2018 American Diabetes Association Standards of Medical Care in Diabetes. An RX edit (short code) alerted the pharmacist when a diabetes medication was verified. An electronic tool complemented the RX edit, through which the pharmacist would assess the patient record for the presence of an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB), aspirin, or a statin. EVALUATION: The pharmacist used an electronic tool to identify gaps in therapy, to document medication therapy problems identified, to make therapeutic recommendations to the patient or provider, and to document interventions using the electronic tool. RESULTS: Pharmacists used the tool 788 times during a 50-day period. Each completion of the tool represented 1 patient profile assessed. Pharmacists identified 99 patients (12.6%) who were not using an ACEI or ARB. Pharmacists recommended ACEI or ARB therapy for 56 patients (56.6%). Pharmacists identified 371 patients (47.1%) who were not using aspirin therapy, and recommended aspirin therapy for 198 patients (53.4%). Pharmacists identified 187 (23.7%) patients who were not given statin therapy and recommended statin therapy for 142 patients (76%). A total of 74 medication therapy problems (18.7%) were resolved. CONCLUSION: An electronic tool was developed and integrated into the dispensing workflow. The implementation of an electronic tool helped community-based pharmacists to identify gaps in therapy and to make recommendations in alignment with American Diabetes Association guidelines.

Functional Data Analysis of high-frequency load curves reveals drivers of residential electricity consumption.

Smart energy meters generate real time, high frequency data which can foster demand management and response of consumers and firms, with potential private and social benefits. However, proper statistical techniques are needed to make sense of this large amount of data and translate them into usable recommendations. Here, we apply Functional Data Analysis (FDA), a novel branch of Statistics that analyses functions-to identify drivers of residential electricity load curves. We evaluate a real time feedback intervention which involved about 1000 Italian households for a period of three years. Results of the FDA modelling reveal, for the first time, daytime-indexed patterns of residential electricity consumption which depend on the ownership of specific clusters of electrical appliances and an overall reduction of consumption after the introduction of real time feedback, unrelated to appliance ownership characteristics.

Using personas to exploit environmental attitudes and behaviour in sustainable product design.

The aim of this research was to study the relationship between user sustainable design attitudes versus behaviour, and to develop and test environmental personas as design tools. Current approaches towards environmentally sustainable design are primarily focused on capturing the environmentally conscious and pro-environmental consumers, or changing the attitude and behaviour of the anti-environmental consumer. In a survey of 521 consumers, environmental attitude was a poor predictor of environmental behaviour. A series of interviews was performed with different profiles of environmentally orientated users to assess their environmental attitudes and behaviour. The survey and interview data were used to develop four personas, one for each of the environmental attitude and behaviour types based on data from the consumer survey. A case study performed with university design students found that concepts generated by groups using environmentally orientated personas scored higher on environmental sustainability versus those generated by groups using an image board. This study illustrates how user-centred design approaches could be used to embed sustainable design in products by exploiting consumer environmental behaviour to overcome different attitudes and behaviour.

BtM, a Low-cost Open-source Datalogger to Estimate the Water Content of Nonvascular Cryptogams.

Communities of nonvascular cryptogams, such as mosses or lichens, are an important part of the Earth's biodiversity, contributing to the regulation of the carbon and nitrogen cycles in many ecosystems. Being poikilohydric organisms, they do not actively control their internal water content and need a humid environment to activate their metabolism. Therefore, studying water relationships of nonvascular cryptogams is crucial to understand both their diversity patterns and their functions in the ecosystems. We present the BtM datalogger, a low-cost open-source platform for the study of the water content of nonvascular cryptogams. The datalogger is designed to measure ambient temperature, humidity, and conductance from up to eight samples simultaneously. We provide a design for a printed circuit board (PCB), a detailed protocol to assemble the components, and the required source code. All this makes the assembly of the BtM datalogger accessible to any research group, even to those without previous specialized knowledge. Therefore, the design presented here has the potential to help popularize the use of this type of device among ecologists and field biologists.

Evaluation of the Impact of the Linac MLC and Gantry Sag in volumetric modulated arc therapy.

PURPOSE: Mechanical sag in the radiotherapy linear accelerator gantry and multi-leaf collimator (MLC) carriage effectively causes systematic deviations in the isocenter with respect to gantry angle. To minimize the impact of this error on treatment, a tolerance value of a 1-mm mechanical isocenter shift is commonly accepted for intensity-modulated radiation therapy quality assurance (QA). However, this tolerance value has not been firmly established for volumetric modulated arc therapy (VMAT) treatments. The purpose of this study is therefore to evaluate the impact of gantry and MLC carriage sag on VMAT clinical performance. METHODS: A published dataset of Elekta and Varian sag measurements served as a starting point for the investigation. Typical sag profiles were chosen and modeled as continuous isocenter deviations in three dimensions. The data were then incorporated into existing Digital Imaging and Communications in Medicine protocol, extended for radiotherapy plans via a "beam-splitting" algorithm. Three treatment sites were investigated in parallel: head and neck, prostate, and prostate with surrounding lymph nodes. Monte Carlo-simulated dose distributions were obtained for varying magnifications of the modeled sag. The resulting dose distributions, including that for no error, were compared qualitatively and quantitatively, against multiple metrics. RESULTS: The dose-volume histograms (DVHs) for all plans exhibited a decrease in planning target volume (PTV) dose uniformity with increasing sag magnification, whereas dose to organs at risk exhibited no coherent trend. The prostate plan was shown to be the most vulnerable to mechanical sag across all considered metrics. However, all plans with peak isocenter deviation less than 1 mm were well within typical cutoff points for each metric. CONCLUSIONS: All avenues of investigation presented substantiate the commonly accepted tolerance value of a 1-mm peak isocenter shift in annual linac QA.

Secondary measures of hand hygiene performance in health care available with continuous electronic monitoring of individuals.

BACKGROUND: Hand hygiene (HH) compliance in health care is usually measured against versions of the World Health Organization's "Your 5 Moments" guidelines using direct observation. Such techniques result in small samples that are influenced by the presence of an observer. This study demonstrates that continuous electronic monitoring of individuals can overcome these limitations. METHODS: An electronic real-time prompting system collected HH data on a musculoskeletal rehabilitation unit for 12 weeks between October 2016 and October 2017. Aggregate and professional group scores and the distributions of individuals' performance within groups were analyzed. Soiled utility room exits were monitored and compared with performance at patient rooms. Duration of patient room visits and the number of consecutive missed opportunities were calculated. RESULTS: Overall, 76,130 patient room and 1,448 soiled utility room HH opportunities were recorded from 98 health care professionals. Aggregate unit performance for patient and soiled utility rooms were both 67%, although individual compliance varied greatly. The number of hand wash events that occurred while inside patient rooms increased with longer visits, whereas HH performance at patient room exit decreased. Eighty-three percent of missed HH opportunities occurred as part of a series of missed events, not in isolation. CONCLUSIONS: Continuous collection of HH data that includes temporal, spatial, and personnel details provides information on actual HH practices, whereas direct observation or dispenser counts show only aggregate trends.

Infinitely large, randomly wired sensors cannot predict their input unless they are close to deterministic.

Building predictive sensors is of paramount importance in science. Can we make a randomly wired sensor "good enough" at predicting its input simply by making it larger? We show that infinitely large, randomly wired sensors are nonspecific for their input, and therefore nonpredictive of future input, unless they are close to deterministic. Nearly deterministic, randomly wired sensors can capture ∼ 10% of the predictive information of their inputs for "typical" environments.

A high DQE water-equivalent EPID employing an array of plastic-scintillating fibers for simultaneous imaging and dosimetry in radiotherapy.

PURPOSE: First measurements of the imaging performance of a novel prototype water-equivalent electronic portal imaging device (EPID) designed for simultaneous imaging and dose verification in radiotherapy and previously characterized by our group for dosimetry are reported. Experiments were conducted to characterize the prototype's imaging performance relative to a standard commercial EPID and Monte Carlo (MC) simulations were performed to quantify the impact of several detector parameters on image quality and to inform the design of a proposed next-generation prototype. METHODS: The prototype EPID utilizes an array of 3 cm long plastic-scintillating fibers in place of the metal plate/phosphor screen in standard EPIDs. Using a clinical 6 MV photon beam, the prototype's modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) were measured and compared to measurements taken using a standard commercial EPID. A sensitivity analysis was then performed using the MC model by quantifying these metrics while varying the values of several geometrical and optical transport parameters that were unspecified by the prototype manufacturer. Finally, the MC model was used to quantify the imaging performance of a proposed next-generation prototype incorporating 1.5 cm long fibers that is better suited for integration with clinical portal imaging and dosimetry systems. RESULTS: The prototype EPID's zero spatial frequency DQE exceeded 3%, more than doubling that measured with the standard EPID (1.25%). This increased DQE was a consequence of using a prototype array detector with a greater equivalent thickness than the combined copper plate and phosphor screen in a standard EPID. The increased thickness of our prototype decreased spatial resolution relative to the standard EPID; however, the prototype EPID NPS was also lower than that measured with the standard EPID across all spatial frequencies. The sensitivity analysis demonstrated that the NPS was strongly affected by the roughness of the boundaries between fiber core and cladding regions. By comparison, the MTF was most sensitive to beam divergence and the presence of air between the fiber array and underlying photodiode panel. Simulations demonstrated that by optimizing these parameters, DQE(0) >4% may be achievable with the proposed next-generation prototype design. CONCLUSIONS: The first measurements characterizing the imaging performance of a novel water-equivalent EPID for imaging and dosimetry in radiotherapy demonstrated a DQE(0) more than double that of a standard EPID. MC simulations further demonstrated the potential for developing a next-generation prototype better suited for clinical translation with even higher DQE.