Isolation of Naegleria lustrarea n. sp. (Excavata, Discoba, Heterolobosea) from the feces of Ambystoma annulatum (Ringed Salamander) in Northwest Arkansas.

The salamander, Ambystoma annulatum, is considered a "species of special concern" in the state of Arkansas, USA, due to its limited geographic range, specialized habitat requirements and low population size. Although metazoan parasites have been documented in this salamander species, neither its native protists nor microbiome have yet been evaluated. This is likely due to the elusive nature and under-sampling of the animal. Here, we initiate the cataloguing of microbial associates with the identification of a new heterlobosean species, Naegleria lustrarea n. sp. (Excavata, Discoba, Heterolobosea), isolated from feces of an adult A. annulatum.

Severity of bronchiectasis predicts use of and adherence to high frequency chest wall oscillation therapy - Analysis from the United States Bronchiectasis and NTM research registry.

BACKGROUND: High frequency chest wall oscillation (HFCWO) is a form of airway clearance therapy that has been available since the mid-1990s and is routinely used by patients suffering from retained pulmonary secretions. Patients with cystic fibrosis (CF), neuromuscular disease (NMD), and other disorders, including bronchiectasis (BE) and COPD (without BE), are commonly prescribed this therapy. Limited evidence exists describing HFCWO use in the BE population, its impact on long-term management of disease, and the specific patient populations most likely to benefit from this therapy. This study sought to characterize the clinical characteristics of patients with BE who have documented use of HFCWO at baseline and 1-year follow-up. METHODS: An analysis from a large national database registry of patients with BE was performed. Demographic and clinical characteristics of all patients receiving HFCWO therapy at baseline are reported. Patients were stratified into two groups based on continued or discontinued use of HFCWO therapy at 1-year follow-up. RESULTS: Over half (54.8 %) of patients who reported using HFCWO therapy had a Modified Bronchiectasis Severity Index (m-BSI) classified as severe, and the majority (81.4 %) experienced an exacerbation in the prior two years. Of patients with 1-year follow-up data, 73 % reported continued use of HFCWO. Compared to patients who discontinued therapy, these patients were more severe at baseline and at follow-up suggesting that patients with more severe disease are more likely to continue HFCWO therapy. CONCLUSIONS: Patients who have more severe disease and continue to experience exacerbations and hospitalizations are more likely to continue HFCWO therapy. CLINICAL TRIAL REGISTRATION: NA.

Vision-Based Control of a Handheld Surgical Micromanipulator with Virtual Fixtures.

Performing micromanipulation and delicate operations in submillimeter workspaces is difficult because of destabilizing tremor and imprecise targeting. Accurate micromanipulation is especially important for microsurgical procedures, such as vitreoretinal surgery, to maximize successful outcomes and minimize collateral damage. Robotic aid combined with filtering techniques that suppress tremor frequency bands increases performance; however, if knowledge of the operator's goals is available, virtual fixtures have been shown to further improve performance. In this paper, we derive a virtual fixture framework for active handheld micromanipulators that is based on high-bandwidth position measurements rather than forces applied to a robot handle. For applicability in surgical environments, the fixtures are generated in real-time from microscope video during the procedure. Additionally, we develop motion scaling behavior around virtual fixtures as a simple and direct extension to the proposed framework. We demonstrate that virtual fixtures significantly outperform tremor cancellation algorithms on a set of synthetic tracing tasks (p < 0.05). In more medically relevant experiments of vein tracing and membrane peeling in eye phantoms, virtual fixtures can significantly reduce both positioning error and forces applied to tissue (p < 0.05).

Circumscribed Choroidal Hemangioma Simulating Choroidal Melanoma on Advanced Ultrawide-Field Pseudocolor Retinal Imaging: A Case Series.

The purpose of this case series was to evaluate the features of circumscribed choroidal hemangioma on pseudocolor ultrawide-field (UWF) retinal images simulating choroidal melanoma and compare it to fundoscopic appearance. All four patients underwent full ophthalmological examination, including dilated fundus examination, ultrasonography, and UWF imaging (UWFI). All circumscribed choroidal hemangioma appeared clinically as orange-red choroidal lesions which were echodense with regular internal structure on ultrasonography. All lesions appeared green-grey in color on pseudocolor UWFI. Pseudocolor UWFI of circumscribed choroidal hemangioma represents distortion of true color appearance and may simulate choroidal melanoma. [Ophthalmic Surg Lasers Imaging Retina 2023;54:292-296.].

Analysis of spatiotemporal variation in dissolved organic carbon concentrations for streams with cropland-dominated watersheds.

It remains a challenge to understand how dissolved organic carbon (DOC) is cycled from farmlands to rivers due to the complex interaction between farming practices, the baseflow hydrology of predominantly flat lowlands, and seasonal environmental influences such as snowpack. To address this, field DOC concentrations were measured monthly throughout the year at sub-basin scales across the Chippewa River Watershed, which falls within the Corn Belt of the Midwestern United States. These DOC dynamics in stream water from croplands were benchmarked against the data sampled from hilly forested areas in the Connecticut River Watershed. The Soil Water Assessment Tool (SWAT) simulation was applied to provide potential predictive variables associated with daily baseflow. Our study outlines a framework using the combination of primary field data, hydrological modeling, and knowledge-based reclassification of Land Use/Land Cover (LULC) data to analyze the viability of modeling the spatial and temporal variations of cropland stream DOC concentrations. Calibration of the SWAT model resulted in the overall daily Nash-Sutcliffe model efficiency coefficient (NSE) of 0.67 and the corresponding R2 = 0.89. Our main results show: 1) baseflow DOC concentrations from croplands were substantially higher throughout the year relative to other landcover areas, especially for spring runoff/snowmelt scenarios, 2) an empirical analysis explained ~82 % of the spatial gradient of annual mean observed DOC concentrations, and 3) with the addition of hydrological simulated variables, a linear model explained ~81 % of monthly and 54 % of daily variations of observed DOC concentrations for cropland sub-basins. Our study identified key factors regulating the spatiotemporal DOC concentrations in cropland streamflow; the contribution here promotes to strengthen future analytical models that link watershed characteristics to carbon cycling processes in a large freshwater ecosystem.

A Review of Rattlesnake Venoms.

Venom components are invaluable in biomedical research owing to their specificity and potency. Many of these components exist in two genera of rattlesnakes, Crotalus and Sistrurus, with high toxicity and proteolytic activity variation. This review focuses on venom components within rattlesnakes, and offers a comparison and itemized list of factors dictating venom composition, as well as presenting their known characteristics, activities, and significant applications in biosciences. There are 64 families and subfamilies of proteins present in Crotalus and Sistrurus venom. Snake venom serine proteases (SVSP), snake venom metalloproteases (SVMP), and phospholipases A2 (PLA2) are the standard components in Crotalus and Sistrurus venom. Through this review, we highlight gaps in the knowledge of rattlesnake venom; there needs to be more information on the venom composition of three Crotalus species and one Sistrurus subspecies. We discuss the activity and importance of both major and minor components in biomedical research and drug development.

Micron: an Actively Stabilized Handheld Tool for Microsurgery.

We describe the design and performance of a hand-held actively stabilized tool to increase accuracy in micro-surgery or other precision manipulation. It removes involuntary motion such as tremor by actuating the tip to counteract the effect of the undesired handle motion. The key components are a three-degree-of-freedom piezoelectric manipulator that has 400 µm range of motion, 1 N force capability, and bandwidth over 100 Hz, and an optical position measurement subsystem that acquires the tool pose with 4 µm resolution at 2000 samples/s. A control system using these components attenuates hand motion by at least 15 dB (a fivefold reduction). By considering the effect of the frequency response of Micron on the human visual feedback loop, we have developed a filter that reduces unintentional motion, yet preserves intuitive eye-hand coordination. We evaluated the effectiveness of Micron by measuring the accuracy of the human/machine system in three simple manipulation tasks. Handheld testing by three eye surgeons and three non-surgeons showed a reduction in position error of between 32% and 52%, depending on the error metric.

Erdafitinib-Induced Secondary Maculopathy.

Purpose: This work presents a case of secondary maculopathy associated with the use of erdafitinib (Balversa) for the management of bladder urothelial carcinoma with bony metastasis. Methods: A case report is presented. Results: A 58-year-old Hispanic man presented with blurry vision 3 weeks after starting erdafitinib for the management of bony metastases associated with urothelial carcinoma. A comprehensive evaluation identified multiple areas of subretinal fluid induced by erdafitinib. Throughout treatment, the ocular condition progressed, causing worsening of vision; this led to discontinuation of the drug. Discontinuation was associated with visual and anatomic function improvement. Conclusions: Fibroblast growth factor receptor (FGFR) plays a major role in maintaining mature and premature retinal pigment epithelium cells. Drugs that inhibit the FGFR pathway block the activation of the mitogen-activated protein kinase pathway, leading to synthesis of antiapoptotic proteins. Erdafitinib is associated with ocular toxicity and leads to multifocal pigment epithelial detachments associated with secondary subretinal fluid.

Longitudinal change in cognitive function and medication adherence in HIV-infected adults.

Neuropsychological (NP) dysfunction has been linked to poor medication adherence among HIV-infected adults. However, there is a dearth of research examining longitudinal changes in the relationship between NP status and adherence rates. We hypothesized that declines in NP functioning would be associated with a corresponding decline in medication adherence while stable NP functioning would be associated with stable or improving adherence rates. Participants included 215 HIV-infected adults who underwent cognitive testing at study entry and six months later. Compared to the NP stable group, the NP decline group showed a greater drop in adherence rates. Further analysis revealed that, beyond global NP, learning and memory was significantly associated with changes in adherence rates. These findings further support the link between cognitive functioning and medication adherence and illustrates the importance of documenting changes in cognitive abilities for identifying individuals at risk for poor adherence.

Subtle deficits in instrumental activities of daily living in subtypes of mild cognitive impairment.

BACKGROUND/AIMS: Greater cognitive and functional deficits in mild cognitive impairment (MCI) are associated with higher rates of dementia. We explored the relationship between these factors by comparing instrumental activities of daily living (IADLs) among cognitive subtypes of MCI and examining associations between IADL and neuropsychological indices. METHODS: We analyzed data from 1,108 MCI and 3,036 normal control subjects included in the National Alzheimer's Coordinating Center Uniform Data Set who were assessed with the Functional Activities Questionnaire (FAQ). RESULTS: IADL deficits were greater in amnestic than nonamnestic MCI, but within these subgroups, did not differ between those with single or multiple domains of cognitive impairment. FAQ indices correlated significantly with memory and processing speed/executive function. CONCLUSIONS: IADL deficits are present in both amnestic MCI and nonamnestic MCI but are not related to the number of impaired cognitive domains. These cross-sectional findings support previous longitudinal reports suggesting that cognitive and functional impairments in MCI may be independently associated with dementia risk.

Utility of the functional activities questionnaire for distinguishing mild cognitive impairment from very mild Alzheimer disease.

Current criteria for mild cognitive impairment (MCI) require "essentially intact" performance of activities of daily living (ADLs), which has proven difficult to operationalize. We sought to determine how well the Functional Activities Questionnaire (FAQ), a standardized assessment of instrumental ADLs, delineates the clinical distinction between MCI and very mild Alzheimer disease (AD). We identified 1801 individuals in the National Alzheimer's Coordinating Center Uniform Data Set with MCI (n=1108) or very mild AD (n=693) assessed with the FAQ and randomized them to the development or test sets. Receiver-operator curve (ROC) analysis of the development set identified optimal cut-points that maximized the sensitivity and specificity of FAQ measures for differentiating AD from MCI and were validated with the test set. ROC analysis of total FAQ scores in the development set produced an area under the curve of 0.903 and an optimal cut-point of 5/6, which yielded 80.3% sensitivity, 87.0% specificity, and 84.7% classification accuracy in the test set. Bill paying, tracking current events, and transportation (P's<0.005) were the FAQ items of greatest diagnostic utility. These data suggest that the FAQ exhibits adequate sensitivity and specificity when used as a standardized assessment of instrumental ADLs in the diagnosis of AD versus MCI.

Semiautomated intraocular laser surgery using handheld instruments.

BACKGROUND AND OBJECTIVE: In laser retinal photocoagulation, hundreds of dot-like burns are applied. We introduce a robot-assisted technique to enhance the accuracy and reduce the tedium of the procedure. MATERIALS AND METHODS: Laser burn locations are overlaid on preoperative retinal images using common patterns such as grids. A stereo camera/monitor setup registers and displays the planned burn locations overlaid on real-time video. Using an active handheld micromanipulator, a 7 x 7 grid of burns spaced 650 microm apart is applied to both paper slides and porcine retina in vitro using 30 milliseconds laser pulses at 532 nm. Two scenarios were tested: unaided, in which the micromanipulator is inert and the laser fires at a fixed frequency, and aided, in which the micromanipulator actively targets burn locations and the laser fires automatically upon target acquisition. Error is defined as the distance from the center of the observed burn mark to the preoperatively selected target location. RESULTS: An experienced retinal surgeon performed trials with and without robotic assistance, on both paper slides and porcine retina in vitro. In the paper slide experiments at an unaided laser repeat rate of 0.5 Hz, error was 125+/-62 microm with robotic assistance and 149+/-76 microm without (P < 0.005), and trial duration was 70+/-8 seconds with robotic assistance and 97+/-7 seconds without (P < 0.005). At a repeat rate of 1.0 Hz, error was 129+/-69 microm with robotic assistance and 166+/-91 microm without (P < 0.005), and trial duration was 26+/-4 seconds with robotic assistance and 47+/-1 seconds without (P < 0.005). At a repeat rate of 2.0 Hz on porcine retinal tissue, error was 123+/-69 microm with robotic assistance and 203+/-104 microm without (P < 0.005). CONCLUSION: Robotic assistance can increase the accuracy of laser photocoagulation while reducing the duration of the operation.

The effectiveness of a mobile high-frequency chest wall oscillation (HFCWO) device for airway clearance.

INTRODUCTION: High-frequency chest wall oscillation (HFCWO) is a commonly prescribed airway clearance technique (ACT) for patients whose ability to expectorate sputum is compromised. This study aimed to assess the effectiveness of a newly developed mobile ACT device (mHFCWO-The Monarch Airway Clearance System) in patients with cystic fibrosis (CF). A standard nonmobile HFCWO device (sHFCWO) was used as a comparator. METHODOLOGY: This was a randomized, open-label, crossover pilot study. CF patients were treated with each device. Sputum was collected during and after each therapy session, while spirometry tests, Brody score assessment and functional respiratory imaging were performed before and after treatments. RESULTS: Wet weight of sputum collected during and after treatment was similar for mHFCWO and sHFCWO (6.53 ± 8.55 vs 5.80 ± 5.82; P = .777). Interestingly, the mHFCWO treatment led to a significant decrease in specific airway volume (9.55 ± 9.96 vs 8.74 ± 9.70 mL/L; P < .001), while increasing specific airway resistance (0.10 ± 0.16 vs 0.16 ± 0.23 KPA*S; P < .001). These changes were heterogeneously-distributed throughout the lung tissue and were greater in the distal areas, suggesting a shift of mucus. Changes were accompanied by an overall improvement in the Brody index (57.71 ± 16.55 vs 55.20 ± 16.98; P = .001). CONCLUSION: The newly developed mobile device provides airway clearance for CF patients comparable to a nonmobile sHFCWO device, yielding a change in airway geometry and patency by the shift of mucus from the more peripheral regions to the central airways.

EyeSLAM: Real-time simultaneous localization and mapping of retinal vessels during intraocular microsurgery.

BACKGROUND: Fast and accurate mapping and localization of the retinal vasculature is critical to increasing the effectiveness and clinical utility of robot-assisted intraocular microsurgery such as laser photocoagulation and retinal vessel cannulation. METHODS: The proposed EyeSLAM algorithm delivers 30 Hz real-time simultaneous localization and mapping of the human retina and vasculature during intraocular surgery, combining fast vessel detection with 2D scan-matching techniques to build and localize a probabilistic map of the vasculature. RESULTS: In the harsh imaging environment of retinal surgery with high magnification, quick shaky motions, textureless retina background, variable lighting and tool occlusion, EyeSLAM can map 75% of the vessels within two seconds of initialization and localize the retina in real time with a root mean squared (RMS) error of under 5.0 pixels (translation) and 1° (rotation). CONCLUSIONS: EyeSLAM robustly provides retinal maps and registration that enable intelligent surgical micromanipulators to aid surgeons in simulated retinal vessel tracing and photocoagulation tasks.

Effect of high-frequency chest wall oscillation on the central and peripheral distribution of aerosolized diethylene triamine penta-acetic acid as compared to standard chest physiotherapy in cystic fibrosis.

BACKGROUND AND OBJECTIVES: High-frequency chest wall oscillation (HFCWO) has been shown to be as effective as standard chest physiotherapy (SCPT) for removal of pulmonary secretions as well as increasing FEV(1) in cystic fibrosis (CF) patients. Patients using HFCWO often administer aerosolized medications simultaneously, reducing time required for daily care. While peripheral pulmonary distribution of tracer in normal subjects has been shown to be unaffected by HFCWO, this has not been studied in CF patients. We evaluated distribution of aerosolized (99m)Tc diethylene triamine penta-acetic acid (DTPA) administered simultaneously with HFCWO and compared this with DTPA aerosolized after SCPT. STUDY DESIGN: Ten CF patients, ages 22 to 38 years, with moderate-to-severe obstructive disease were studied in a crossover design after documentation of stable lung function. (133)Xe was administered to delineate total lung volume. DTPA was aerosolized (Pari LC Plus nebulizer and Pulmo-Aide compressor; Pari Respiratory Equipment Inc.; Richmond, VA) to delineate airway deposition. The central to peripheral deposition ratio (C/P ratio) of each lung was analyzed in each study group. Central regions were represented by the inner one third of the (133)Xe scan as demonstrated in previous research models. RESULTS: The mean C/P ratio (+/- SD) for both lungs was 1.45 +/- 0.31 with HFCWO and 1.46 +/- 0.28 following SCPT (p = not significant [NS]). Right lung mean C/P ratio was 1.74 +/- 0.43 with HFCWO and 1.85 +/- 0.63 after SCPT (p = NS). Left lung mean C/P ratio was 1.25 +/- 0.29 with HFCWO and 1.21 +/- 0.35 after SCPT (p = NS). There was no correlation between C/P ratio and FEV(1) or FVC. CONCLUSIONS: Use of HFCWO in combination with aerosolized DTPA did not result in increased central deposition as compared with aerosolized DTPA administered after SCPT. Further study is required to determine if combining HFCWO with aerosolized medications can be modified to improve peripheral deposition.

Assessing efficacy of high-frequency chest wall oscillation in patients with familial dysautonomia.

STUDY OBJECTIVE: To determine the benefits of daily use of high-frequency chest wall oscillation (HFCWO) in familial dysautonomia (FD) patients with lung disease. DESIGN: Pulmonary function tests, chest radiographs, and blood tests were performed on entry to the study. A retrospective chart review of 12 months prior to entry provided baseline data regarding respiratory illnesses, medications, doctor visits, hospitalizations, and absenteeism. Daily logs provided prospective data on these parameters as well as HFCWO usage. Evaluations were performed at 1, 3, 6, 9, and 12 months for pulse oximetry, spirometry, and log review. At the exit evaluation, blood tests and chest radiographs were repeated. PATIENTS: Fifteen FD patients with history of lung disease requiring daily inhalation therapy (7 female and 8 male; age range, 11 to 33 years) were enrolled in a 1-year clinical trial of HFCWO therapy. Two subjects withdrew after 3 months and 6 months, respectively. Each individual served as his/her own control. RESULTS: Oxygen saturation improved by 1 month (median, 97.5%; interquartile range [IQR], 96 to 98%; vs median, 94%; IQR, 89 to 96%) and was sustained at exit evaluation (median, 98%; IQR, 98 to 98%) [p = 0.004]. Median FVC and peak expiratory flow rate (PEFR) were the pulmonary function measures with sustained improvement from baseline to exit (p = 0.02 and p = 0.03, respectively). When retrospective and prospective data were compared, all measured health outcomes improved significantly, including pneumonias (p = 0.0156), hospitalizations (p = 0.0161), antibiotic courses (p = 0.0005), antibiotic days (p = 0.0002), doctor visits (p = 0.0005), and absenteeism (p = 0.0002). CONCLUSION: In this limited study of FD patients, HFCWO effected significant improvements in all measured health outcomes and oxygen saturation; FVC and PEFR were the pulmonary function measures demonstrating sustained improvement.

"A players" or "A positions"? The strategic logic of workforce management.

Companies simply can't afford to have "A players" in all positions. Rather, businesses need to adopt a portfolio approach to workforce management, systematically identifying their strategically important A positions, supporting B positions, and surplus C positions, then focusing disproportionate resources on making sure A players hold A positions. This is not as obvious as it may seem, because the three types of positions do not reflect corporate hierarchy, pay scales, or the level of difficulty in filling them. A positions are those that directly further company strategy and, less obviously, exhibit wide variation in the quality of the work done by the people who occupy them. Why variability? Because raising the average performance of individuals in these critical roles will pay huge dividends in corporate value. If a company like Nordstrom, for example, whose strategy depends on personalized service, were to improve the performance of its frontline sales associates, it could reap huge revenue benefits. B positions are those that support A positions or maintain company value. Inattention to them could represent a significant downside risk. (Think how damaging it would be to an airline, for example, if the quality of its pilots were to drop.) Yet investing in them to the same degree as A positions is ill-advised because B positions don't offer an upside potential. (Pilots are already highly trained, so channeling resources into improving their performance would probably not create much competitive advantage.) And C positions? Companies should consider outsourcing them--or eliminating them. We all know that effective business strategy requires differentiating a firm's products and services in ways that create value for customers. Accomplishing this requires a differentiated workforce strategy, as well.

A tale of two city blocks: differences in immature and adult mosquito abundances between socioeconomically different urban blocks in Baltimore (Maryland, USA).

Infrastructure degradation in many post-industrial cities has increased the availability of potential mosquito habitats, including container habitats that support infestations of invasive disease-vectors. This study is unique in examining both immature and adult mosquito abundance across the fine-scale variability in socio-economic condition that occurs block-to-block in many cities. We hypothesized that abundant garbage associated with infrastructure degradation would support greater mosquito production but instead, found more mosquito larvae and host-seeking adults (86%) in parcels across the higher socio-economic, low-decay block. Aedes albopictus and Culex pipiens were 5.61 (p < 0.001) and 4.60 (p = 0.001) times more abundant, respectively. Most discarded (garbage) containers were dry during peak mosquito production, which occurred during the 5th hottest July on record. Containers associated with human residence were more likely to hold water and contain immature mosquitoes. We propose that mosquito production switches from rain-fed unmanaged containers early in the season to container habitats that are purposefully shaded or watered by mid-season. This study suggests that residents living in higher socioeconomic areas with low urban decay may be at greater risk of mosquito-borne disease during peak mosquito production when local container habitats are effectively decoupled from environmental constraints.

Real-Time Retinal Vessel Mapping and Localization for Intraocular Surgery.

Computer-aided intraocular surgery requires precise, real-time knowledge of the vasculature during retinal procedures such as laser photocoagulation or vessel cannulation. Because vitreoretinal surgeons manipulate retinal structures on the back of the eye through ports in the sclera, voluntary and involuntary tool motion rotates the eye in the socket and causes movement to the microscope view of the retina. The dynamic nature of the surgical workspace during intraocular surgery makes mapping, tracking, and localizing vasculature in real time a challenge. We present an approach that both maps and localizes retinal vessels by temporally fusing and registering individual-frame vessel detections. On video of porcine and human retina, we demonstrate real-time performance, rapid convergence, and robustness to variable illumination and tool occlusion.

Potential trends in Attention Deficit Hyperactivity Disorder (ADHD) drug use on a college campus: wastewater analysis of amphetamine and ritalinic acid.

Attention Deficit Hyperactivity Disorder (ADHD) medication use is on the rise in the United States. The most widely used ADHD medications are the amphetamine-type compounds Adderall (mixed amphetamine salts) and Ritalin (methylphenidate). According to survey data ADHD medications are used as a study drug or "Smart Drug" by students without a prescription on college campuses. Survey data of non-prescribed drug use has limitations with accurate reporting and no empirical data of usage exists in the literature. This study looks for trends in the use of these drugs on a college campus among low-stress and high stress periods. The metabolites of these two drugs, amphetamine and ritalinic acid, are quantified in campus wastewater using solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Trends show a possible increase in amphetamine levels during periods of high stress such as midterms, the last week of classes and finals week over levels from the baseline low stress weeks such as the first week of classes. Both semesters from the 2011-12 academic year were studied and the highest increase over baseline (760%) occurred during finals week of the second semester. Ritalinic acid levels gradually climbed first semester but had no obvious periodic trend second semester.