Combined Effects Of Age Research Articles

Three‐dimensional Surface Area of the Distal Biceps Enthesis, Relationship to Body Size, Sex, Age and Secular Changes in a 20th Century American Sample

ABSTRACTThis study quantifies the influence of body size, sex, age and birth year (secular changes) on the 3D rugose surface area of thebiceps brachiiattachment site in a sample of 85 White individuals from the Robert J. Terry Collection. Entheseal surface areas were collected using a NextEngine ™ 3D scanner. Several osteometric measurements of the upper limb were used in the initial analysis to determine which were most suitable for use as a body size proxy. In general, articular dimensions correlate more strongly with biceps entheseal surface area than long bone lengths. The distal articular breadth of the humerus shows the strongest correlation with biceps surface area for men (n = 48,r = 0.504) and women (n = 37,r = 0.646). Men are larger bodied and have larger entheseal surface areas; however, women have larger biceps entheses relative to body size. Although the study sample was limited to individuals between the ages 30 and 49 years, age at death still explains approximately 8% of the variation in enthesis size for women (r = 0.284). Men are unequally distributed by age across birth years, and the results for age and secular change are ambiguous because their effects cannot be separated. Birth year explains about 30% of the variation in female rugose entheseal surface area (r = −0.552). Age and birth year together explain about 34% of the variation in enthesis size for men. Overall, body size is the single most significant variable for both men and women, while the combined effects of age and secular change present a nearly equivalent influence on 3D surface area of thebiceps brachiienthesis in this 20th century American sample. Copyright © 2013 John Wiley & Sons, Ltd.

Experimental dissociation of individual quality, food and timing of breeding effects on double-brooding in a migratory songbird

Annual reproductive success in many species is influenced by the number of breeding attempts within a season. Although previous studies have shown isolated effects of female quality, food, and timing of breeding on the probability of female birds producing second broods, to our knowledge, none have tested the relative importance of multiple factors and their interactions using simultaneous manipulations within populations of free-living birds. In this study, we show that individual quality and timing of breeding interact to affect the probability of double-brooding in female mountain bluebirds (Sialia currucoides). High-quality females (those that naturally initiated clutches early in the season) were more likely to double-brood, regardless of whether their hatching date was advanced or delayed, whereas later breeding, lower quality females were much less likely to double-brood when their first attempt was delayed. This indicates that annual fecundity of poorer quality (or younger) female bluebirds may be more sensitive to seasonal variation in environmental conditions. In addition, birds that were provided with supplemental food throughout first breeding attempts were more likely to double-brood in one of the study years, suggesting that female bluebirds may be energetically limited in their capacity to initiate a second brood. Females that had their first brood delayed also had a shorter inter-brood interval and were moulting fewer feathers during second broods compared to controls, while females in better condition showed more advanced moult in second breeding attempts. Taken together, our results demonstrate the combined effects of age- or individual quality-mediated energetic trade-offs between current and future reproduction, and between investments in offspring and self-maintenance, on annual fecundity of female birds.

Effect of Aging and Human Immunodeficiency Virus Infection on Cognitive Abilities

To explore the combined effects of aging and human immunodeficiency virus (HIV) infection on cognitive decay. Cross-sectional, single-cohort study. Institute of Clinical Infectious Diseases, Catholic University of the Sacred Heart, Rome, Italy. One hundred fifty-three asymptomatic HIV-positive (HIV+) outpatients (20% aged ≥ 60) and an age- and education-matched control population of 39 HIV-negative individuals. A neuropsychological investigation was conducted to compare four groups of participants classified on the basis of HIV serostatus and age (<60 vs ≥ 60). The effects of age and HIV infection on neuropsychological performance were analyzed using a two-by-two factorial analysis of variance. Demographic and clinical variables associated with neuropsychological performance were identified using linear regression analysis in the HIV+ population. HIV infection and aging had significant negative effects on cognitive performance, but no significant interaction was observed between these two factors. Although older HIV+ participants had worse cognitive performance, they showed no distinct cognitive pattern from younger HIV+ participants. Moreover, younger HIV+ participants' performance on memory tasks was qualitatively and quantitatively comparable with that of older HIV- participants, despite the dramatic age difference. Aging and HIV might be additive factors in the expression of cognitive decline. As the HIV+ population ages, routine neuropsychological examinations could help clinicians better understand and manage the expression of cognitive impairment.

Lower limbs composition and radiographic knee osteoarthritis (RKOA) in Chingford sample—A longitudinal study

Our aim in this longitudinal study was to evaluate to what extent fat and lean tissue mass variations are associated and can predict RKOA in a large sample of British women followed-up over 10 years. Kellgren/Lawrence (K/L), joint space narrowing (JSN) and osteophyte (OSP) grades were scored from radiographs of both knees in 909 middle-aged women from the Chingford registry. Body composition components were assessed using the dual energy X-ray absorptiometry (DXA) method. In cross-sectional analysis, combined effect of age, BMI and leg tissue composition was required for best fitting model explaining variations of K/L scoring and osteophytes at lateral compartment. To explain medial osteophytes, age and BMI were sufficient to generate the best fitting model. In prediction analysis, leg lean mass was the more powerful predictor of K/L, medial osteophytes than BMI. In conclusion, BMI appears to influence the development of knee OA through both fat and/or lean mass, depending on RKOA phenotype.

Impact of Age and Comorbidities on Long-term Survival of Patients with High-risk Prostate Cancer Treated with Radical Prostatectomy: A Multi-institutional Competing-risks Analysis

BackgroundSurvival after surgical treatment using competing-risk analysis has been previously examined in patients with prostate cancer (PCa). However, the combined effect of age and comorbidities has not been assessed in patients with high-risk PCa who might have heterogeneous rates of competing mortality despite the presence of aggressive disease. ObjectiveTo examine the risk of 10-yr cancer-specific mortality (CSM) and other-cause mortality (OCM) according to clinical and pathologic characteristics of patients treated with radical prostatectomy (RP) for high-risk PCa. Design, setting, and participantsWithin a multi-institutional cohort, 3828 men treated with RP for high-risk PCa (defined as the presence of at least one of these risk factors: prostate-specific antigen >20 ng/ml, biopsy Gleason score 8–10, clinical stage ≥T3) were identified. InterventionAll patients underwent RP and pelvic lymph node dissection. Outcome measurements and statistical analysisCompeting-risk Poisson regression analyses were performed to simultaneously assess the 10-yr CSM and OCM rates after RP. The same analyses were also conducted after stratification of patients according to age at surgery, comorbidity status assessed by the Charlson Comorbidity Index (CCI), and number of risk factors (one vs two or more). Results and limitationsOverall, 229 patients (5.9%) died from PCa; 549 (14.3%) died from other causes. The 10-yr CSM and OCM rates ranged from 5.1% to 12.8% and from 4.3% to 37.4%, respectively. Age and CCI were the major determinants of OCM; their impact on CSM was minimal. OCM was the leading cause of death in all patient groups except in young men (≤59 yr) with no comorbidities, regardless of the number of risk factors (10-yr CSM and OCM 6.9–12.8% and 5.5–6.3%, respectively). The main limitation was the lack of patients managed conservatively. ConclusionsEven in the context of high-risk PCa, long-term CSM after RP is modest and represents the leading cause of death only in young, healthy patients. Conversely, older and sicker patients with multiple risk factors are at the highest risk of dying from OCM while sharing very low CSM rates.

In vitro salicylate does not further impair aging-induced brain mitochondrial dysfunction

Aging and drug-induced side effects may contribute to the deterioration of mitochondrial bioenergetics in the brain. One hypothesis is that the combination of both deleterious stimuli accelerates the process of mitochondrial degradation, leading to progressive bioenergetic disruption. The hypothesis was tested by analyzing the isolated and combined effect of aging and salicylate, a vastly used anti-inflammatory drug, on isolated brain fractions in rats.Male Wistar rats were divided according to age in two groups: adult (n=8, 19 weeks of age) and aged (n=8, 106 weeks of age). In vitro endpoints of brain mitochondrial function including oxygen consumption and transmembrane electric potential (ΔΨ) were evaluated in the absence and in the presence of salicylate (0.5mM). Brain mitochondrial susceptibility to calcium-induced permeability transition pore (MPTP) was also assessed. Mitochondrial oxidative stress was determined by measuring aconitase and manganese-superoxide dismutase (SOD) activity, and content in sulfhydryl groups (SH) and malondialdehyde (MDA). Mitochondrial content in apoptotic-related proteins Bax, Bcl-2 and cyclophilin D was determined by Western Blotting.Under basal, untreated, conditions, aging affected brain mitochondrial state 3 respiration, maximal ΔΨ developed, ADP phosphorylation lag phase and calcium-induced MPTP. Interestingly, MDA decreased and Mn-SOD activity increased in the aged group. Brain mitochondrial Bcl-2 content decreased and Bax/Bcl-2 ratio increased in aged group. Salicylate incubation for 20min increased lipid peroxidation in the aged group only and stimulated respiration during state 2, accompanied by decreased ΔΨ, although both effects were independent of the animal age.We confirmed that both aging and salicylate per se impaired brain mitochondrial bioenergetics, although the combination of both does not seem to worsen the mitochondrial end-points studied.

The effect of steam sterilization on the accuracy of spring-style mechanical torque devices for dental implants

BackgroundMechanical torque devices (MTDs) are one of the most commonly recommended devices used to deliver optimal torque to the screw of dental implants. Recently, high variability has been reported about the accuracy of spring-style mechanical torque devices (S-S MTDs). Joint stability and survival rate of fixed implant supported prosthesis depends on the accuracy of these devices. Currently, there is limited information on the steam sterilization influence on the accuracy of MTDs. The purpose of this study was to assess the effect of steam sterilization on the accuracy (±10% of the target torque) of spring-style mechanical torque devices for dental implants.Materials and methodsFifteen new S-S MTDs and their appropriate drivers from three different manufacturers (Nobel Biocare, Straumann [ITI], and Biomet 3i [3i]) were selected. Peak torque of devices (5 in each subgroup) was measured before and after autoclaving using a Tohnichi torque gauge. Descriptive statistical analysis was used and a repeated-measures ANOVA with type of device as a between-subject comparison was performed to assess the difference in accuracy among the three groups of spring-style mechanical torque devices after sterilization. A Bonferroni post hoc test was used to assess pairwise comparisons.ResultsBefore steam sterilization, all the tested devices stayed within 10% of their target values. After 100 sterilization cycles, results didn’t show any significant difference between raw and absolute error values in the Nobel Biocare and ITI devices; however the results demonstrated an increase of error values in the 3i group (P < 0.05). Raw error values increased with a predictable pattern in 3i devices and showed more than a 10% difference from target torque values (maximum difference of 14% from target torque was seen in 17% of peak torque measurements).ConclusionWithin the limitation of this study, steam sterilization did not affect the accuracy (±10% of the target torque) of the Nobel Biocare and ITI MTDs. Raw error values increased with a predictable pattern in 3i devices and showed more than 10% difference from target torque values. Before expanding upon the clinical implications, the controlled and combined effect of aging (frequency of use) and steam sterilization needs more investigation.

The effect of steam sterilization on the accuracy of spring-style mechanical torque devices for dental implants

The effect of steam sterilization on the accuracy of spring-style mechanical torque devices for dental implants Minoo Mahshid,1 Aboulfazl Saboury,1 Ali Fayaz,1 Seyed Jalil Sadr,1 Friedrich Lampert,2 Maziar Mir2,31Department of Prosthodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran; 2Department of Conservative Dentistry, Aachen RWTH Hospital, Aachen, Germany; 3Beckman Laser Institute, UCI, Irvine, CA, USABackground: Mechanical torque devices (MTDs) are one of the most commonly recommended devices used to deliver optimal torque to the screw of dental implants. Recently, high variability has been reported about the accuracy of spring-style mechanical torque devices (S-S MTDs). Joint stability and survival rate of fixed implant supported prosthesis depends on the accuracy of these devices. Currently, there is limited information on the steam sterilization influence on the accuracy of MTDs. The purpose of this study was to assess the effect of steam sterilization on the accuracy (&plusmn;10% of the target torque) of spring-style mechanical torque devices for dental implants.Materials and methods: Fifteen new S-S MTDs and their appropriate drivers from three different manufacturers (Nobel Biocare, Straumann [ITI], and Biomet 3i [3i]) were selected. Peak torque of devices (5 in each subgroup) was measured before and after autoclaving using a Tohnichi torque gauge. Descriptive statistical analysis was used and a repeated-measures ANOVA with type of device as a between-subject comparison was performed to assess the difference in accuracy among the three groups of spring-style mechanical torque devices after sterilization. A Bonferroni post hoc test was used to assess pairwise comparisons.Results: Before steam sterilization, all the tested devices stayed within 10% of their target values. After 100 sterilization cycles, results didn&#39;t show any significant difference between raw and absolute error values in the Nobel Biocare and ITI devices; however the results demonstrated an increase of error values in the 3i group (P &lt; 0.05). Raw error values increased with a predictable pattern in 3i devices and showed more than a 10% difference from target torque values (maximum difference of 14% from target torque was seen in 17% of peak torque measurements).Conclusion: Within the limitation of this study, steam sterilization did not affect the accuracy (&plusmn;10% of the target torque) of the Nobel Biocare and ITI MTDs. Raw error values increased with a predictable pattern in 3i devices and showed more than 10% difference from target torque values. Before expanding upon the clinical implications, the controlled and combined effect of aging (frequency of use) and steam sterilization needs more investigation.Keywords: accuracy, steam sterilization, mechanical torque devices, spring-style, dental implants

Three-Phase Asymmetric Transformer Aging Considering Voltage-Current Harmonic Interactions, Unbalanced Nonlinear Loading, Magnetic Couplings, and Hysteresis

A new aging calculation method for three-phase three-leg power transformers under (un)balanced and (non)sinusoidal operating conditions is proposed where the impacts of magnetic saturation, couplings, and hysteresis are accurately included. The aging estimation is carried out through a recently developed and validated time-domain model of a nonlinear three-phase three-leg transformer. The model outputs are used to compute aging based on Arrhenius' thermal reaction theory. The combined aging effects from transformer core asymmetry and load nonlinearity, as well as current and voltage harmonic interactions from nonsinusoidal input excitations and nonlinear loading are considered in the calculation. The model improves upon the conventional weighted harmonic factor (WHF) approach of aging estimation by direct evaluation of additional fundamental and harmonic losses generated by the iron-core, nonlinear loads, and terminal voltage distortions. The main contribution is a new transformer aging estimation method with wider applicability to three-phase transformers considering harmonic current-voltage interactions from unbalanced nonlinear loads, terminal voltage distortions and imbalances, as well as magnetic hysteresis and flux-coupling effects in asymmetric iron-core structures. Several case studies are presented for comparing the proposed model based aging method with the conventional WHF approach.

Heat-resistant Al–0.2Sc–0.04Zr electrical conductor

The combined effects of ageing and cold-rolling on the tensile and conductive properties of Al–0.2Sc–0.04Zr alloys were investigated. Both the tensile strength and electrical conductivity of alloys after cold-rolling+ageing or pre-ageing+cold-rolling+ageing treatments are apparently better than that of the only aged alloy; furthermore, the improvements on the properties made by pre-ageing+cold-rolling+ageing are slightly greater than that by cold-rolling+ageing. TEM observations indicate that the increase of strength should be associated with the formation of finer Al3(ScZr) precipitates and substructure with boundaries pinned by nano-sized precipitates while the improvement of conductivity should be caused by the closure of microvoids. As an electrical conductor, the highest working temperature of Al–0.2Sc–0.04Zr with the best strength and conductivity can be as high as 345°C. It strongly suggests that the Al–Sc–Zr alloy has a great application prospect in heat resistant conductor fields.

Cumulative impact of common genetic variants and other risk factors on colorectal cancer risk in 42 103 individuals

ObjectiveColorectal cancer (CRC) has a substantial heritable component. Common genetic variation has been shown to contribute to CRC risk. A study was conducted in a large multi-population study to assess...

Combined effects of aging and HIV infection on semantic verbal fluency: A view of the cortical hypothesis through the lens of clustering and switching

The profile of HIV-associated neurocognitive disorders (HAND) has classically been characterized as “subcortical,” but questions have arisen as to whether aging with HIV in the antiretroviral therapy era has subtly shifted the expression of HAND into a more “cortical” disorder (e.g., decay of semantic memory stores). We evaluated this hypothesis by examining semantic fluency and its component processes (i.e., clustering and switching) in 257 individuals across four groups stratified by age (<40 and ≥50 years) and HIV serostatus. Jonckheere–Terpstra tests revealed significant monotonic trends for the combined effects of HIV and aging on overall semantic (and letter) fluency and switching, but not cluster size, with greatest deficits evident in the older adults with HIV infection. Within the older HIV-infected cohort, poorer switching was uniquely associated with self-reported declines in instrumental activities of daily living and deficits in learning and executive functions, but not semantic memory. Results suggest that HIV infection and aging may confer adverse additive effects on the executive components of semantic fluency (i.e., switching), rather than a degradation of semantic memory stores (i.e., cluster size), which is a profile that is most consistent with combined frontostriatal neuropathological burden of these two conditions.

Heart failure and cardiorenal syndrome in the elderly

In the view of the aging of the general population and particularly the aging of the dialysis population, it is of considerable interest to examine the combined effects of age and uremia on cardiovascular status. The effects of uremia per se interact with the effects of aging in cardiovascular end-organ damage and in the genesis of heart failure (HF) and cardiorenal syndrome (CRS). Structural abnormalities with fibrosis and calcification of the heart and central arteries, along with autonomic nervous system dysfunction, underlie reduced cardiac performance leading to cardiac decompensation and HF. HF in the elderly is characterized by the heart's inability to maintain an adequate cardiac output and may be the result of systolic dysfunction or reduced compliance and diastolic dysfunction. In the elderly, HF symptoms are generally light, upon admission to the hospital, while HF is sometimes in an advanced stage. The pathophysiology of CRS involves interrelated hemodynamic and neurohormonal mechanisms that in the elderly are often increased/emphasized because there is no compensatory response. The therapy of HF and CRS in the elderly with chronic kidney disease is almost entirely empirical since there are no large trials of drugs to reduce mortality and morbidity in this setting. This may lead nephrologists and cardiologists managing these patients toward a sort of "therapeutic nihilism." But this is not the attitude we should adopt in the elderly. Instead we should make a rather careful assessment of each patient and use a personalized treatment that takes into consideration the characteristics of the individual patient and his or her cardiac and renal history as well as social context.

Effects of Age and Localized Muscle Fatigue on Ankle Plantar Flexor Torque Development

Older adults often experience age-related declines in strength, which contribute to fall risk. Such age-related levels of fall risk may be compounded by further declines in strength caused by acute muscle fatigue. Both age- and fatigue-related strength reductions likely impact the ability to quickly develop joint torques needed to arrest falls. Therefore, the purpose of this study was to investigate the combined effects of age and localized muscle fatigue on lower extremity joint torque development. Young (mean age, 26 (2.5) years) and older (mean age, 71 (2.8) years) healthy male adults performed an isometric ankle plantar flexion force control task before and after an ankle plantar flexor fatiguing exercise. Force control performance was quantified using onset time, settling time, and rate of torque development. Age-related increases and decreases were observed for onset time and rate of torque development, respectively. A fatigue-related decrease in rate of torque development was observed in young, but not older adults. The results suggest performance declines that may relate to older adults' reduced ability to prevent falls. A fatigue-related performance decline was observed among young adults, but not older, suggesting the presence of age-related factors such as motor unit remodeling and alterations in perceived exertion. Older adults demonstrated an overall reduction in the ability to quickly produce ankle torque, which may have implications for balance recovery and fall risk among older adults.

Superior Recognition Performance for Happy Masked and Unmasked Faces in Both Younger and Older Adults

In the aging literature it has been shown that even though emotion recognition performance decreases with age, the decrease is less for happiness than other facial expressions. Studies in younger adults have also revealed that happy faces are more strongly attended to and better recognized than other emotional facial expressions. Thus, there might be a more age independent happy face advantage in facial expression recognition. By using a backward masking paradigm and varying stimulus onset asynchronies (17–267 ms) the temporal development of a happy face advantage, on a continuum from low to high levels of visibility, was examined in younger and older adults. Results showed that across age groups, recognition performance for happy faces was better than for neutral and fearful faces at durations longer than 50 ms. Importantly, the results showed a happy face advantage already during early processing of emotional faces in both younger and older adults. This advantage is discussed in terms of processing of salient perceptual features and elaborative processing of the happy face. We also investigate the combined effect of age and neuroticism on emotional face processing. The rationale was previous findings of age-related differences in physiological arousal to emotional pictures and a relation between arousal and neuroticism. Across all durations, there was an interaction between age and neuroticism, showing that being high in neuroticism might be disadvantageous for younger, but not older adults’ emotion recognition performance during arousal enhancing tasks. These results indicate that there is a relation between aging, neuroticism, and performance, potentially related to physiological arousal.

Hormone therapy use and mammographic density in postmenopausal Norwegian women

While studies have shown that use of postmenopausal hormone therapy with estrogen and progestogen (EPT) increases mammographic density, aspects of this association remain unclear. We examined whether mammographic density differed by type of hormone therapy (HT) used, dose, duration of use, time since last use, and whether the effects are modified by age and body mass index (BMI). Using a cross-sectional design, we recruited 2,424 postmenopausal women aged 50-69 years participating in the Norwegian Breast Cancer Screening Program. Mammographic density was assessed with a computer-assisted method, and we estimated mean absolute and percent mammographic density through multiple linear regression, and adjusting for possible confounders. Mammographic density was higher among current HT users (percent density: 22.6%; 95% CI: 22.1-23.2%) than among former (17.7%; 17.2-18.2%) or never users (16.3%; 15.7-16.8%). The highest density was seen in current EPT users of high-dose norethisterone acetate (NETA) regimens who had a percent density of 26.2% (24.3-28.1%). Results differed when considering the combined effect of age and BMI. The effect of EPT on mammographic density was modified by age and BMI, with no apparent association among the youngest women (aged 50-55) with the highest BMI (BMI ≥ 26). A higher mammographic density was found in EPT users compared to never HT users, particularly in women using high-dose NETA regimens. Age and BMI modified the association between EPT use and mammographic density.

Intraindividual variability in HIV infection: Evidence for greater neurocognitive dispersion in older HIV seropositive adults.

Both the prevalence and incidence of HIV infection among older adults are on the rise. Older adults are at increased risk of HIV-associated neurocognitive disorders, which have historically been characterized as an inconsistent or "spotty" pattern of deficits. Dispersion is a form of intraindividual variability (IIV) that is defined as within-person variability in performance across domains and has been associated with poorer neurocognitive functioning and incipient decline among healthy older adults. To our knowledge, no studies have yet examined dispersion in an aging HIV-infected sample. For the current study we examined the hypothesis that age and HIV infection have synergistic effects on dispersion across a battery of clinical and experimental cognitive tasks. Our well-characterized sample comprised 126 HIV-seropositive individuals (HIV+) and 40 HIV-seronegative comparison individuals (HIV-), all of whom were administered a comprehensive neuropsychological battery. Consistent with our hypothesis, an age by HIV serostatus interaction was observed, with the older HIV+ group demonstrating a higher level of dispersion relative to older HIV- and younger HIV+ individuals, even when potentially confounding demographic and medical factors were controlled. Our results demonstrate that older HIV+ adults produce greater dispersion, or intraindividual variability in performance across a range of tests, which may be reflective of cognitive dyscontrol to which this population is vulnerable, perhaps driven by the combined effects of aging and HIV infection on prefrontostriatal systems.

Light-Induced Retinal Degeneration Correlates with Changes in Iron Metabolism Gene Expression, Ferritin Level, and Aging

Retinal degeneration is associated with iron accumulation in several rodent models in which iron-regulating proteins are impaired. Oxidative stress is catalyzed by unbound iron. The role of the heavy chain of ferritin, which sequesters iron, in regulating the thickness of the photoreceptor nuclear layer in the 4- and 16-month-old wild-type H ferritin (HFt(+/+)) and heterozygous H ferritin (HFt(+/-)) mice was investigated, before and 12 days after exposure to 13,000-lux light for 24 hours. The regulation of gene expression of the various proteins involved in iron homeostasis, such as transferrin, transferrin receptor, hephaestin, ferroportin, iron regulatory proteins 1 and 2, hepcidin, ceruloplasmin, and heme-oxygenase 1, was analyzed by quantitative (q)RT-PCR during exposure (2, 12, and 24 hours) and 24 hours after 1 day of exposure in the 4-month-old HFt(+/+) and HFt(+/-) mouse retinas. Retinal degeneration in the 4-month-old HFt(+/-) mice was more extensive than in the HFt(+/+) mice. Yet, it was more extensive in both of the 16-month-old mouse groups, revealing the combined effect of age and excessive light. Injury caused by excessive light modified the temporal gene expression of iron-regulating proteins similarly in the HFt(+/-) and HFt(+/+) mice. Loss of one allele of H ferritin appears to increase light-induced degeneration. This study highlighted that oxidative stress related to light-induced injury is associated with major changes in gene expression of iron metabolism proteins.

Effect of Age, Initiator Status, and Infidelity on Women's Divorce Adjustment

Divorce can be a distressing event. Although various studies have been conducted to better understand this phenomenon, little research has focused on the combined effect of age, initiator status, spousal infidelity, and spiritual well-being on divorce adjustment. To determine the effect of these 4 factors on divorce adjustment, 133 divorced women in the United States were surveyed using the Fisher Divorce Adjustment Scale, Spiritual Well-Being Scale, and a participant questionnaire. Results indicate that initiator status, spousal infidelity, and spiritual well-being together can predict 38% of the variance in overall divorce adjustment for women. Spiritual well-being was found to be the strongest contributor. Recommendations for researchers and implications for clinicians are discussed.

Combined aging effects of strain and thermocycling on unload deflection modes of nickel-titanium closed-coil springs: An in-vitro comparative study

There are no reports on the aging effects of thermocycling of nickel-titanium (NiTi) based coil springs, and few studies have investigated their superelasticity phases in full. In this study, we compared the mechanical properties of NiTi-based closed-coil springs after the combined aging effects of prolonged strain and thermocycling, as a reflection of the clinical situation. Ninety NiTi-based closed-coil springs were used, 30 each of the following types: (1) Nitinol (3M Unitek, Monrovia, Calif), (2) Ni-Ti (Ormco, Glendora, Calif), and (3) RMO (Rocky Mountain Orthodontics, Denver, Colo); all had similar dimensions (length, 12 mm). In each sample group, 2 equal subgroups of 15 coil springs were extended by either 50% (to 18 mm) or 150% (to 30 mm), immersed in artificial saliva, and kept at 37°C for 45 days. All springs underwent sessions of 1000 thermocycles (1 minute long) from 5°C to 55°C on days 22 and 45. Unload deflection curves from both the 50% and 150% extensions (according to their strain subgroups) were recorded by using a universal testing machine before the strain (baseline) and at both 22 and 45 days, immediately after thermocycling. At baseline, the loads exerted by the NiTi-based coil springs varied from 99.8 to 245.1 gf for the RMO (50% strain) and Ni-Ti (150% strain) groups. Statistically significant, although small, differences were seen at each time point in both the 50% and 150% strain subgroups; generally, the highest and lowest values were recorded in the Ni-Ti and Nitinol groups (all, P <0.001). Only the Nitinol coil-spring group showed an acceptable superelasticity phase. The strain and thermocycling did not dramatically change the deactivation forces of any coil springs. NiTi-based closed-coil springs might not have a superelasticity phase, and prolonged strain and thermocycling do not produce clinically relevant alterations in their deactivation forces.