Prevalence of glaucoma. The Beaver Dam Eye Study

PURPOSE

The purpose of this study is to determine the prevalence of glaucoma in the population participating in the Beaver Dam Eye Study (n = 4926).

METHODS

All subjects were examined according to standard protocols, which included applanation tonometry, examination of the anterior chamber, perimetry, grading of fundus photographs of the optic disc, and a medical history interview. Visual field, cup-to-disc ratio, and intraocular pressure (IOP) criteria were used to define the presence of open-angle glaucoma. Definite open-angle glaucoma was defined by the presence of any two or all three of the following: abnormal visual field, large or asymmetric cup-to-disc ratio, high IOP.

RESULTS

The overall prevalence of definite open-angle glaucoma was 2.1%. The prevalence increased with age from 0.9% in people 43 to 54 years of age to 4.7% in people 75 years of age or older. There was no significant effect of sex after adjusting for age. Of the 104 cases of definite open-angle glaucoma, 33 had IOPs less than 22 mmHg in the involved eye. Hemorrhage on the optic disc was found in 46 people; 2 of these had glaucoma. Narrow-angle glaucoma was rare, with two definite cases in the population.

CONCLUSION

The prevalence of open-angle glaucoma in Beaver Dam is similar to that in other white populations. Findings from this study re-emphasize the notion that estimates of glaucoma prevalence should be based on assessing multiple risk indicators.

Hospital admission risk profile (HARP): identifying older patients at risk for functional decline following acute medical illness and hospitalization

OBJECTIVES

To develop and validate an instrument for stratifying older patients at the time of hospital admission according to their risk of developing new disabilities in activities of daily living (ADL) following acute medical illness and hospitalization.

DESIGN

Multi-center prospective cohort study.

SETTING

Four university and two private non-federal acute care hospitals.

PATIENTS

The development cohort consists of 448 patients and the validation cohort consists of 379 patients who were aged 70 and older and who were hospitalized for acute medical illness between 1989 and 1992.

MEASUREMENTS

All patients were evaluated on hospital admission to identify baseline demographic and functional characteristics and were then assessed at discharge and 3 months after discharge to determine decline in ADL functioning.

RESULTS

Logistic regression analysis identified three patient characteristics that were independent predictors of functional decline in the development cohort: increasing age, lower admission Mini-Mental Status Exam scores, and lower preadmission IADL function. A scoring system was developed for each predictor variable and patients were assigned to low, intermediate, and high risk categories. The rates of ADL decline at discharge for the low, intermediate, and high risk categories were 17%, 28%, and 56% in the development cohort and 19%, 31%, and 55% in the validation cohort, respectively. Patients in the low risk category were significantly more likely to recover ADL function and to avoid nursing home placement during the 3 months after discharge.

CONCLUSION

Hospital Admission Risk Profile (HARP) is a simple instrument that can be used to identify patients at risk of functional decline following hospitalization. HARP can be used to identify patients who might benefit from comprehensive discharge planning, specialized geriatric care, and experimental interventions designed to prevent/reduce the development of disability in hospitalized older populations.

Surface acoustic wave actuated cell sorting (SAWACS)

We describe a novel microfluidic cell sorter which operates in continuous flow at high sorting rates. The device is based on a surface acoustic wave cell-sorting scheme and combines many advantages of fluorescence activated cell sorting (FACS) and fluorescence activated droplet sorting (FADS) in microfluidic channels. It is fully integrated on a PDMS device, and allows fast electronic control of cell diversion. We direct cells by acoustic streaming excited by a surface acoustic wave which deflects the fluid independently of the contrast in material properties of deflected objects and the continuous phase; thus the device underlying principle works without additional enhancement of the sorting by prior labelling of the cells with responsive markers such as magnetic or polarizable beads. Single cells are sorted directly from bulk media at rates as fast as several kHz without prior encapsulation into liquid droplet compartments as in traditional FACS. We have successfully directed HaCaT cells (human keratinocytes), fibroblasts from mice and MV3 melanoma cells. The low shear forces of this sorting method ensure that cells survive after sorting.

The relationship of cardiovascular disease and its risk factors to age-related maculopathy. The Beaver Dam Eye Study

PURPOSE

To examine the association between cardiovascular disease and its risk factors to age-related maculopathy in a population-based study of people between the ages of 43 and 86 years (n = 4926) between 1988 and 1990.

METHODS

Population-based prevalence study using standardized protocols for physical examination, blood collection, administration of a questionnaire, and stereoscopic color fundus photography to determine age-related maculopathy. Standard univariate and multivariate analyses were performed.

RESULTS

After controlling for age, early age-related maculopathy was related to low total serum cholesterol levels in women and a high high-density lipoprotein (HDL) cholesterol level and a low total cholesterol/HDL-cholesterol ratio in men. After controlling for age and sex, age-related exudative macular degeneration was associated with higher hematocrit values (odds ratio, 1.09; 95% confidence interval, 1.00, 1.19) and higher leukocyte count (odds ratio, 1.10; 95% confidence interval, 1.00, 1.19). There was no statistically significant relationship between blood pressure, hypertension, or history of cardiovascular disease and exudative macular degeneration or geographic atrophy.

CONCLUSION

With the exception of relationships between serum lipids and early age-related maculopathy, and hematocrit values, leukocyte counts, and exudative macular degeneration, these data suggest that most cardiovascular disease risk factors are not related to age-related maculopathy. Further longitudinal study is needed.

Clinical pharmacy services and hospital mortality rates

We evaluated the associations between clinical pharmacy services and mortality rates in 1029 United States hospitals. A data base was constructed from Medicare mortality rates from the Health Care Financing Administration and the National Clinical Pharmacy Services data base. A multivariate regression analysis, controlling for severity of illness, was employed to determine the associations. Four clinical pharmacy services were associated with lower mortality rates: clinical research (p<0.0001), drug information (p=0.043), drug admission histories (p=0.005), and participation on a cardiopulmonary resuscitation (CPR) team (p=0.039). The actual number of deaths (lower) associated with the presence of these four services were clinical research 21,125 deaths in 108 hospitals, drug information 10,463 deaths in 237 hospitals, drug admission histories 3843 deaths in 30 hospitals, and CPR team participation 5047 deaths in 282 hospitals. This is the first study to indicate that both centrally based and patient-specific clinical pharmacy services are associated with reduced hospital mortality rates. This suggests that these services save a significant number of lives in our nation's hospitals.

Long-term efficacy of radon spa therapy in rheumatoid arthritis--a randomized, sham-controlled study and follow-up

OBJECTIVE

To quantify the efficacy of a series of baths containing natural radon and carbon dioxide (1.3 kBq/l, 1.6 g carbon dioxide/l on average) versus artificial carbon dioxide baths alone in patients with rheumatoid arthritis.

SUBJECTS

Sixty patients participating in an in-patient rehabilitation programme including a series of 15 baths were randomly assigned to two groups.

DESIGN

Pain intensity (100 mm visual analogue scale) and functional restrictions [Keitel functional test, Arthritis Impact Measurement Scales (AIMS questionnaire)] were measured at baseline, after completion of treatment and 3 and 6 months thereafter. To investigate whether the overall value of the outcomes was the same in both groups, the overall mean was analysed by Student's t-test for independent samples.

RESULTS

The two groups showed a similar baseline situation. After completion of treatment, relevant clinical improvements were observed in both groups, with no notable group differences. However, the follow-up revealed sustained effects in the radon arm, and a return to baseline levels in the sham arm. After 6 months, marked between-group differences were found for both end-points (pain intensity: -16.9%, 95% confidence interval -27.6 to -6.2%; AIMS score: 0.57, 95% confidence interval 0.16 to 0.98). The between-group differences were statistically significant for both overall means (pain intensity, P: = 0.04; AIMS, P: = 0.01).

CONCLUSION

Marked short-term improvements in both groups at the end of treatment may have masked potential specific therapeutic effects of radon baths. However, after 6 months of follow-up the effects were lasting only in patients of the radon arm. This suggests that this component of the rehabilitative intervention can induce beneficial long-term effects.

Clinical pharmacy services, pharmacy staffing, and the total cost of care in United States hospitals

This study evaluated direct relationships and associations among clinical pharmacy services, pharmacist staffing, and total cost of care in United States hospitals. A database was constructed from the 1992 American Hospital Association's Abridged Guide to the Health Care Field and the 1992 National Clinical Pharmacy Services Database. A multiple regression analysis, controlling for severity of illness, was employed to determine the relationships and associations. The study population consisted of 1016 hospitals. Six clinical pharmacy services were associated with lower total cost of care: drug use evaluation (p=0.001), drug information (p=0.003), adverse drug reaction monitoring (p=0.008), drug protocol management (p=0.001), medical rounds participation (p=0.0001), and admission drug histories (p=0.017). Two services were associated with higher total cost of care: total parenteral nutrition (TPN) team participation (p=0.001) and clinical research (p=0.0001). Total costs of care/hospital/year were lower when any of six clinical pharmacy services were present: drug use evaluation $1,119,810.18 (total $1,005,589,541.64 for the 898 hospitals offering the service), drug information $5,226,128.22 (total $1,212,461,747.04 for the 232 hospitals offering the service), adverse drug reporting monitoring $1,610,841.02 (total $1,101,815, 257.68 for the 684 hospitals offering the service), drug protocol management $1,729,608.41 (total $614,010,985.55 for the 355 hospitals offering the service), medical rounds participation $7,979,720.45 (total $1,212,917,508.41 for the 152 hospitals offering the service), and admission drug histories $6,964,145.17 (total $208,924,355.10 for the 30 hospitals offering the service). Clinical research $9,558,788.01 (total $1,013,231,529.06 for the 106 hospitals offering the service) and TPN team participation $3,211,355.12 (total $1,027,633,638.43 for the 320 hospitals offering the service) were associated with higher total costs of care. As staffing increased for hospital pharmacy administrators (p=0.0001) and clinical pharmacists (p=0.007), total cost of care decreased. As staffing increased for dispensing pharmacists, total cost of care increased (p=0.006). Based on this total cost of care model, optimal hospital pharmacy administrator staffing was 2.01/100 occupied beds. Staffing for dispensing pharmacists should be as low as possible, and definitely fewer than 5.11/100 occupied beds. Staffing for clinical pharmacists should be as high as possible, but definitely more than 1.11/100 occupied beds. The results of this study suggest that increased staffing levels of clinical pharmacists and pharmacy administrators, as well as some clinical pharmacy services, were associated with reduced total cost of care in United States hospitals.

Health care professional staffing, hospital characteristics, and hospital mortality rates

To evaluate associations among hospital characteristics, staffing levels of health care professionals, and mortality rates in 3763 United States hospitals, a data base was constructed from the American Hospital Association's Abridged Guide to the Health Care Field and hospital Medicare mortality rates from the Health Care Financing Administration. A multivariate regression analysis controlling for severity of illness was employed to determine the associations. Hospital characteristics associated with lower mortality were occupancy rate and private nonprofit and private for-profit ownership. Mortality rates decreased as staffing level per occupied bed increased for medical residents, registered nurses, registered pharmacists, medical technologists, and total hospital personnel. Mortality rates increased as staffing level per occupied bed increased for hospital administrators and licensed practical-vocational nurses. To our knowledge, this is the first study to show that pharmacists were associated with lower mortality rates.

Interrelationships among mortality rates, drug costs, total cost of care, and length of stay in United States hospitals: summary and recommendations for clinical pharmacy services and staffing

We evaluated interrelationships and associations among mortality rates, drug costs, total cost of care, and length of stay in United States hospitals. Relationships between these variables and the presence of clinical pharmacy services and pharmacy staffing also were explored. A database was constructed from the 1992 American Hospital Association's Abridged Guide to the Health Care Field, the 1992 National Clinical Pharmacy Services database, and 1992 Health Care Finance Administration mortality data. A severity of illness-adjusted multiple regression analysis was employed to determine relationships and associations. Study populations ranged from 934-1029 hospitals (all hospitals for which variables could be matched). The only pharmacy variable associated with positive outcomes with all four health care outcome measures was the number of clinical pharmacists/occupied bed. That figure tended to have the greatest association (slope) with reductions in mortality rate, drug costs, and length of stay. As clinical pharmacist staffing levels increased from the tenth percentile (0.34/100 occupied beds) to the ninetieth percentile (3.23/100 occupied beds), hospital deaths declined from 113/1000 to 64/1000 admissions (43% decline). This resulted in a reduction of 395 deaths/hospital/year when clinical pharmacist staffing went from the tenth to the ninetieth percentile. This translated into a reduction of 1.09 deaths/day/hospital having clinical pharmacy staffing between these staffing levels, or 320 dollars of pharmacist salary cost/death averted. Three hospital pharmacy variables were associated with reduced length of stay in 1024 hospitals: drug protocol management (slope -1.30, p=0.008), pharmacist participation on medical rounds (slope -1.71, p<0.001), and number of clinical pharmacists/occupied bed (slope -26.59, p<0.001). As drug costs/occupied bed/year increased, severity of illness-adjusted mortality rates decreased (slope -38609852, R(2) 8.2%, p<0.0001). As the total cost of care/occupied bed/year increased, those same mortality rates decreased (slope -5846720642, R(2) 14.9%, p<0.0001). Seventeen clinical pharmacy services were associated with improvements in the four variables.

Medication errors in United States hospitals

This study evaluated hospital demographics, staffing, pharmacy variables, health care outcomes measures (severity of illness-adjusted mortality rates, drug costs, total cost of care, and length of stay) and medication errors. A database was constructed from the 1992 American Hospital Association's Abridged Guide to the Health Care Field, the 1992 National Clinical Pharmacy Services database, and 1992 mortality data from the Health Care Financing Administration. Simple statistical tests and a severity of illness-adjusted multiple regression analysis were employed. The study population consisted of 1116 hospitals that reported information on medication errors and 913 hospitals that reported information on medication errors that adversely affected patient care outcomes. We evaluated factors associated with the 430,586 medication errors and 17,338 medication errors that adversely affected patient care outcomes. Medication errors occurred in 5.07% of the patients admitted each year to these hospitals. Each hospital experienced a medication error every 22.7 hours (every 19.73 admissions). Medication errors that adversely affected patient care outcomes occurred in 0.25% of all patients admitted to these hospitals/year. Each hospital experienced a medication error that adversely affected patient care outcomes every 19.23 days (or every 401 admissions). The following factors were associated with increased medication errors/occupied bed/year: lack of pharmacy teaching affiliation (slope = 0.8875, p=0.0416), centralized pharmacists (slope = 1.0942, p=0.0001), number of registered nurses/occupied bed (slope = 1.624, p=0.032), number of registered pharmacists/occupied bed (slope = 25.0573, p=0.0001), hospital mortality rate (slope = 2.8017, p=0.0192), and total cost of care/occupied bed/year (slope = 0.01432, p=0.0091). Factors associated with decreased medication errors were location in the Mid-Atlantic census region (slope = -1.5182, p=0.03), affiliation with a pharmacy teaching program (slope = -1.0252, p=0.0349), decentralized pharmacists (slope = -0.9843, p=0.0037), and number of medical residents/occupied bed (slope = -1.478, p=0.0014). There was a 45% decrease in medication errors (1.81-fold decrease) in hospitals that had decentralized pharmacists, compared with hospitals that had centralized pharmacists. In addition, there was a 94% decrease in medication errors that adversely affected patient care outcomes (16.88-fold decrease) in hospitals that had decentralized pharmacists compared with hospitals that had only centralized pharmacists. Based on previous field studies and our findings in 1116 hospitals, it appears that one of the most effective ways to prevent or reduce medication errors is to decentralize pharmacists to patient care areas. The results of this study should help hospitals reduce the number of medication errors that occur each year.

Diagnostic x-ray exposure and lens opacities: the Beaver Dam Eye Study

The Beaver Dam Eye Study is a population-based study of common age-related eye diseases. During the standardized medical history, the 4926 subjects were asked whether they had ever had a chest x-ray, computerized axial tomography (CAT) scan of the head, other x-rays of the head, x-rays of the abdomen, or other diagnostic x-rays. The eye examination included photographs of the lenses of the eyes, which were subsequently graded according to protocol. Nuclear sclerosis and posterior subcapsular opacity were significantly associated with CAT scans. If these relationships are causal, it would highlight the importance of minimizing such exposure to the lens of the eye.

Clinical pharmacy services, pharmacist staffing, and drug costs in United States hospitals

We evaluated direct relationships and associations among clinical pharmacy services, pharmacist staffing, and drug costs in United States hospitals. A database was constructed from the 1992 American Hospital Association's Abridged Guide to the Health Care Field and the 1992 National Clinical Pharmacy Services database. Multiple regression analysis, controlling for severity of illness, was employed to determine the associations. The study population consisted of 934 hospitals. Four clinical pharmacy services were associated with lower drug costs: in-service education, $77,879.19+/-$56,203.42 (a total of $48,518,735.37 for the 623 hospitals offering this service, p=0.016); drug information, $430,579.84+/-$299,232.76 ($90,852,346.24 for the 211 hospitals offering this service, p=0.015); drug protocol management, $137,333.67+/-$98,617.83 ($45,045,443.76 for the 328 hospitals offering this service, p=0.049); and admission drug histories, $213,388.21+/-$201,537.85 ($5,548,093.46 for the 26 hospitals offering this service, p=0.011). As staffing increased for hospital pharmacy administrators (p<0.0001), dispensing pharmacists (p<0.0001), and pharmacy technicians (p<0.0001), drug costs increased. As staffing increased for clinical pharmacists, drug costs decreased (p=0.018). The results of this study show that increased staff levels of clinical pharmacists and some clinical pharmacy services are associated with reduced hospital drug costs.

Traveling surface acoustic wave (TSAW) microfluidic fluorescence activated cell sorter (μFACS)

We report a microfluidic fluorescence activated cell-sorting (μFACS) device that employs traveling surface acoustic waves (TSAW) to sort cells at rates comparable to conventional jet-in-air FACS machines, with high purity and viability. The device combines inertial flow focusing and sheath flow to align and evenly space cells, improving the sorting accuracy and screening rate. We sort with an interdigital transducer (IDT) whose tapered geometry allows precise positioning of the TSAW for optimal cell sorting. We sort three different cell lines at several kHz, at cell velocities exceeding one meter per second, while maintaining both sorting purity and cell viability at around 90% simultaneously.

18F-FDG-PET Detects Drastic Changes in Brain Metabolism in the Tg4-42 Model of Alzheimer's Disease

The evaluation of new therapeutic strategies in Alzheimer’s disease (AD) relies heavily on in vivo imaging and suitable animal models that mimic the pathological changes seen in patients. ¹⁸F-Fluorodeoxyglucose (¹⁸F-FDG)-positron-emission tomography (PET) is a well-established non-invasive imaging tool for monitoring changes in cerebral brain glucose metabolism in vivo. ¹⁸F-FDG-PET is used as a functional biomarker for AD as patients show an early and progressive reduction of cerebral glucose metabolism. However, earlier studies in preclinical models of AD showed conflicting results. The aim of this study was the evaluation of cerebral glucose metabolism in the Tg4–42 mouse model of AD using ¹⁸F-FDG-PET/magnetic resonance imaging (MRI). Tg4–42 mice show an age-dependent reduction in glucose metabolism together with severe neuron loss and memory deficits. Similar to AD patients early decrease in ¹⁸F-FDG uptake was already detected in young (3 months) Tg4–42 mice. The altered glucose metabolism coupled with age- and disease related cognitive decline of Tg4–42 mice make it a well-suited model for preclinical testing of AD-relevant therapeutics.

Analysis of Motor Function in the Tg4-42 Mouse Model of Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder and the most common form of dementia. Hallmarks of AD are memory impairments and cognitive deficits, but non-cognitive impairments, especially motor dysfunctions are also associated with the disease and may even precede classic clinical symptoms. With an aging society and increasing hospitalization of the elderly, motor deficits are of major interest to improve independent activities in daily living. Consistent with clinical findings, a variety of AD mouse models develop motor deficits as well. We investigated the motor function of 3- and 7-month-old Tg4-42 mice in comparison to wild-type controls and 5XFAD mice and discuss the results in context with several other AD mouse model. Our study shows impaired balance and motor coordination in aged Tg4-42 mice in the balance beam and rotarod test, while general locomotor activity and muscle strength is not impaired at 7 months. The cerebellum is a major player in the regulation and coordination of balance and locomotion through practice. Particularly, the rotarod test is able to detect cerebellar deficits. Furthermore, supposed cerebellar impairment was verified by 18F-FDG PET/MRI. Aged Tg4-42 mice showed reduced cerebellar glucose metabolism in the 18F-FDG PET. Suggesting that, deficits in coordination and balance are most likely due to cerebellar impairment. In conclusion, Tg4-42 mice develop motor deficits before memory deficits, without confounding memory test. Thus, making the Tg4-42 mouse model a good model to study the effects on cognitive decline of therapies targeting motor impairments.

Enhanced surface acoustic wave cell sorting by 3D microfluidic-chip design

We demonstrate an acoustic wave driven microfluidic cell sorter that combines advantages of multilayer device fabrication with planar surface acoustic wave excitation. We harness the strong vertical component of the refracted acoustic wave to enhance cell actuation by using an asymmetric flow field to increase cell deflection. Precise control of the 3-dimensional flow is realized by topographical structures implemented on the top of the microchannel. We experimentally quantify the effect of the structure dimensions and acoustic parameter. The design attains cell sorting rates and purities approaching those of state of the art fluorescence-activated cell sorters with all the advantages of microfluidic cell sorting.

Visualization of Surface Acoustic Waves in Thin Liquid Films

We demonstrate that the propagation path of a surface acoustic wave (SAW), excited with an interdigitated transducer (IDT), can be visualized using a thin liquid film dispensed onto a lithium niobate (LiNbO3) substrate. The practical advantages of this visualization method are its rapid and simple implementation, with many potential applications including in characterising acoustic pumping within microfluidic channels. It also enables low-cost characterisation of IDT designs thereby allowing the determination of anisotropy and orientation of the piezoelectric substrate without the requirement for sophisticated and expensive equipment. Here, we show that the optical visibility of the sound path critically depends on the physical properties of the liquid film and identify heptane and methanol as most contrast rich solvents for visualization of SAW. We also provide a detailed theoretical description of this effect.

Ten years experience with lung and heart-lung transplantation in primary and secondary pulmonary hypertension

OBJECTIVE

Patients with primary pulmonary hypertension (PPHT) have a worse natural outcome compared with those with secondary pulmonary hypertension in Eisenmenger's syndrome (ES) and chronic pulmonary embolism (CPE). Lung transplantation (SLTx, DLTx, HLTx) still remains the only therapeutical option for patients with this type of endstage lung disease.

METHODS

From 1988 to 1998, 63 patients underwent lung transplantation for PPHT (n=29, 9 m, 20 f, 2 SLTx, 14 DLTx, 13 HLTx), ES (n=29, 13 m, 16 f, 2 SLTx, 3 DLTx, 24 HLTx) or CPE (n=5, 2 m, 3 f, 1 SLTx, 2 DLTx, 2 HLTx). Groups were comparable for NYHA functional class, preoperative pulmonary arterial pressure, recipient and donor age, ischemic time, necessity and duration of cardiopulmonary bypass and cross-match.

RESULTS

The 1-, 3- and 5-year survival was 52, 40 and 35% for the PPHT-group, 83, 78 and 74% for the ES-group and 80, 60 and 60% for the CPE-group, respectively (P=0.026, P=0.033, P=0.082 for 1-, 3- and 5-year survival). Patients following DLTx showed a lower 1-year survival rate as compared with patients after HLTx both in PPHT patients (36 vs. 62%, P=0.091) and in ES patients (67 vs. 83%, P=0.213). The incidence of bronchiolitis obliterans syndrome was 29% at 1 year and 45% at 3 years for the PPHT-group vs. 17 and 65% for the ES-group (n. s. in between groups). Excluding postoperative ventilation time (PPHT-group: 26.8+/-24.0 days vs. ES-group: 16.1+/-30.8 days, P=0. 011) and a higher incidence of infectious causes of death (PPHT-group n=8 vs. ES-group n=1, P=0.017) groups were comparable with regard to their postoperative courses.

CONCLUSIONS

It is concluded, that predominantly the underlying primary disease influences graft survival after lung transplantation in patients with pulmonary hypertension compared with all other patient and procedure dependent factors. Lung transplantation in patients with PPHT requires further investigations to achieve results comparable with other indications.

Bimorph material/structure designs for high sensitivity flexible surface acoustic wave temperature sensors

A fundamental challenge for surface acoustic wave (SAW) temperature sensors is the detection of small temperature changes on non-planar, often curved, surfaces. In this work, we present a new design methodology for SAW devices based on flexible substrate and bimorph material/structures, which can maximize the temperature coefficient of frequency (TCF). We performed finite element analysis simulations and obtained theoretical TCF values for SAW sensors made of ZnO thin films (~5 μm thick) coated aluminum (Al) foil and Al plate substrates with thicknesses varied from 1 to 1600 μm. Based on the simulation results, SAW devices with selected Al foil or plate thicknesses were fabricated. The experimentally measured TCF values were in excellent agreements with the simulation results. A normalized wavelength parameter (e.g., the ratio between wavelength and sample thickness, λ/h) was applied to successfully describe changes in the TCF values, and the TCF readings of the ZnO/Al SAW devices showed dramatic increases when the normalized wavelength λ/h was larger than 1. Using this design approach, we obtained the highest reported TCF value of −760 ppm/K for a SAW device made of ZnO thin film coated on Al foils (50 μm thick), thereby enabling low cost temperature sensor applications to be realized on flexible substrates.

Binary Colloidal Nanoparticle Concentration Gradients in a Centrifugal Field at High Concentration

Binary colloidal nanoparticles have been found to form different types of crystalline phases at varied radial positions in a centrifugal field by Chen et al. ( ACS Nano 2015, 9, 6944-50). The variety of binary phase behaviors resulted from the two different nanoparticle concentration gradients, but to date, the gradients can only be empirically controlled. For the first time, we are able to measure, fit, and simulate binary hard-sphere colloidal nanoparticle concentration gradients at high particle concentrations up to 30 vol %, which enables tailor-made gradients in a centrifugal field. By this means, a continuous range of binary particle concentration ratios can be accessed in one single experiment to obtain an extended phase diagram. By dispersing two differently sized silica nanoparticles labeled with two different fluorescence dyes in a refractive index matching solvent, we can use a multi-wavelength analytical ultracentrifuge (MWL-AUC) to measure the individual concentration gradient for each particle size in sedimentation-diffusion equilibrium. The influence of the remaining slight turbidity at high concentration can be corrected using the MWL spectra from the AUC data. We also show that the experimental concentration gradients can be fitted using a noninteracting nonideal sedimentation model. By using these fitted parameters, we are able to simulate nanoparticle concentration gradients, which agreed with the subsequent experiments at a high concentration of 10 vol % and thus allowed for the simulation of binary concentration gradients of hard-sphere nanoparticles in preparative ultracentrifuges (PUCs). Finally we demonstrated that by simulating the concentration gradients in PUCs, a continuous and extended binary nanoparticle phase diagram can be obtained by simply studying the structure evolution along the centrifugal field for one single sample instead of a large number of experiments with discrete compositions as in conventional studies.

Optical imaging of concealed brain activity using a gold mirror in honeybees

Brain activity is inherently combinatorial and three-dimensional. Optical imaging techniques offer a suitable opportunity to record many activity foci simultaneously, but under conventional microscopy conditions, optical access is generally limited to the frontal part of the brain. Thus, even for cases in which optical recordings have delivered substantial data, our knowledge of deeper layers is deficient. Using the honeybee olfactory system as a test system, we report that by using a gold-sputtered cover slip as a minute mirror, it is possible to optically access and record from otherwise inaccessible brain areas. In insects, the first brain area to code for odors is the antennal lobe (comparable to the vertebrate olfactory bulb). Several previous studies have characterized glomerular odor response patterns of the frontal view, readily accessible when the head capsule of the bee is opened. However, until now, the back and the sides of the antennal lobe have remained utterly unexplored. This is particularly relevant because in the honeybee these two views coincide with two separate olfactory subsystems, related to two axonal tracts of second-order neurons: the lAPT and the mAPT. Combining wide-field microscopy, calcium imaging, and a minute mirror, we report the first glomerular odor responses from the side of the honeybee antennal lobe.

Thrombin stimulates Ca-channel currents in isolated frog ventricular cells

Effects of the proteolytic enzyme thrombin in the modulation of cardiac Ca-channel currents were examined in single ventricular cells from frog myocardium, using the whole-cell voltage clamp technique (Hamill et al. 1981). Application of 3.8.10(-9) M thrombin to the bath increased the peak of the Ca-channel current by 84 +/- 35% (8 cells). Hirudin (31.10(-9) M), a specific thrombin inhibitor, blocked the thrombin-induced increase of this current. The increase in the current can be made responsible for the measured positive inotropic effects of thrombin as well as for the shift of the plateau voltage of the action potentials towards more positive values.

Acoustic erythrocytometer for mechanically probing cell viscoelasticity

We demonstrate an acoustic device to mechanically probe a population of red blood cells at the single cell level. The device operates by exciting a surface acoustic wave in a microfluidic channel creating a stationary acoustic wave field of nodes and antinodes. Erythrocytes are attracted to the nodes and are deformed. Using a stepwise increasing and periodically oscillating acoustic field we study the static and dynamic deformation of individual red blood cells one by one. We quantify the deformation by the Taylor deformation index D and relaxation times τ₁ and τ₂ that reveal both the viscous and elastic properties of the cells. The precision of the measurement allows us to distinguish between individual cells in the suspension and provides a quantitative viscoelastic fingerprint of the blood sample at single cell resolution. The method overcomes limitations of other techniques that provide averaged values and has the potential for high-throughput.

In vivo Imaging With 18F-FDG- and 18F-Florbetaben-PET/MRI Detects Pathological Changes in the Brain of the Commonly Used 5XFAD Mouse Model of Alzheimer's Disease

Imaging biomarkers of Alzheimer's disease (AD) that are able to detect molecular changes in vivo and transgenic animal models mimicking AD pathologies are essential for the evaluation of new therapeutic strategies. Positron-emission tomography (PET) using either ¹⁸F-Fluorodeoxyglucose (¹⁸F-FDG) or amyloid-tracers is a well-established, non-invasive tool in the clinical diagnostics of AD assessing two major pathological hallmarks. ¹⁸F-FDG-PET is able to detect early changes in cerebral glucose metabolism and amyloid-PET shows cerebral amyloid load. However, the suitability of ¹⁸F-FDG- and amyloid-PET in the widely used 5XFAD mouse model of AD is unclear as only a few studies on the use of PET biomarkers are available showing some conflicting results. The aim of this study was the evaluation of ¹⁸F-FDG-PET and amyloid-PET in 5XFAD mice in comparison to neurological deficits and neuropathological changes. Seven- and 12-month-old male 5XFAD mice showed a significant reduction in brain glucose metabolism in ¹⁸F-FDG-PET and amyloid-PET with ¹⁸F-Florbetaben demonstrated an increased cerebral amyloid deposition (n = 4-6 per group). Deficits in spatial reference memory were detected in 12-month-old 5XFAD mice in the Morris Water Maze (n = 10-12 per group). Furthermore, an increased plaque load and gliosis could be proven immunohistochemically in 5XFAD mice (n = 4-6 per group). PET biomarkers ¹⁸F-FDG and ¹⁸F-Florbetaben detected cerebral hypometabolism and increased plaque load even before the onset of severe memory deficits. Therefore, the 5XFAD mouse model of AD is well-suited for in vivo monitoring of AD pathologies and longitudinal testing of new therapeutic approaches.

Quantitative Brain Positron Emission Tomography in Female 5XFAD Alzheimer Mice: Pathological Features and Sex-Specific Alterations

Successful back-translating clinical biomarkers and molecular imaging methods of Alzheimer's disease (AD), including positron emission tomography (PET), are very valuable for the evaluation of new therapeutic strategies and increase the quality of preclinical studies. ¹⁸F-Fluorodeoxyglucose (FDG)–PET and ¹⁸F-Florbetaben–PET are clinically established biomarkers capturing two key pathological features of AD. However, the suitability of ¹⁸F-FDG– and amyloid–PET in the widely used 5XFAD mouse model of AD is still unclear. Furthermore, only data on male 5XFAD mice have been published so far, whereas studies in female mice and possible sex differences in ¹⁸F-FDG and ¹⁸F-Florbetaben uptake are missing. The aim of this study was to evaluate the suitability of ¹⁸F-FDG– and ¹⁸F-Florbetaben–PET in 7-month-old female 5XFAD and to assess possible sex differences between male and female 5XFAD mice. We could demonstrate that female 5XFAD mice showed a significant reduction in brain glucose metabolism and increased cerebral amyloid deposition compared with wild type animals, in accordance with the pathology seen in AD patients. Furthermore, we showed for the first time that the hypometabolism in 5XFAD mice is gender-dependent and more pronounced in female mice. Therefore, these results support the feasibility of small animal PET imaging with ¹⁸F-FDG- and ¹⁸F-Florbetaben in 5XFAD mice in both, male and female animals. Moreover, our findings highlight the need to account for sex differences in studies working with 5XFAD mice.