Hip fracture risk rises 100 to 1000-fold over 60 years of ageing. Loss of resistance to bending is not a major feature of normal ageing of the femoral neck. Another cause of fragility is local ...buckling or elastic instability. Bones adapt to their local experience of mechanical loading. The suggestion that bipedalism allows thinning of the underloaded superolateral femoral neck cortex arises from the failure of walking to transmit much mechanical load to this region. We aimed to measure whether elastic instability increases greatly with age since it might trigger hip fracture in a sideways fall.
We measured with computed tomography the distribution of bone in the mid-femoral neck of 77 proximal femurs from people who died suddenly aged 20–95 years. We then calculated the critical stress, from the geometric properties and density of the cortical zone most highly loaded in a sideways fall, as a threshold for elastic instability.
With normal ageing, this thin cortical zone in the upper femoral neck became substantially thinner. Relative to mean values at age 60 years, female cortical thickness declined by 6·4% (SD 1·1) per decade (p<0·0001), and critical stress by 13·2% (4·3) per decade (p=0·004) in the superoposterior octant compressed most in a sideways fall. Similar, but significantly smaller, effects were evident in men (p=0·004). This thinning compromised the capacity of the femur to absorb energy independently of osteoporosis. Patients with hip fracture had further reduced stability.
As women age, hip fragility increases because underloading of the superolateral cortex leads to atrophic thinning. Because walking does not sufficiently load the upper femoral neck, the fragile zones in healthy bones may need strengthening, for example with more well targeted exercise.
Hip fracture risk rises 100‐ to 1000‐fold over six decades of age, but only a minor part of this increase is explained by declining BMD. A potentially independent cause of fragility is cortical ...thinning predisposing to local crushing, in which bone tissue's material disintegrates at the microscopic level when compressed beyond its capacity to maintain integrity. Elastic instability or buckling of a much thinned cortex might alternatively occur under compression. In a buckle, the cortex moves approximately at right angles to the direction of load, thereby distorting its microstructure, eventually to the point of disintegration. By resisting buckling movement, trabecular buttressing would protect the femoral neck cortex against this type of failure but not against crushing. We quantified the effect of aging on trabecular BMD in the femoral neck and assessed its contribution to cortical elastic stability, which determines resistance to buckling. Using CT, we measured ex vivo the distribution of bone in the midfemoral necks of 35 female and 33 male proximal femurs from cases of sudden death in those 20–95 yr of age. We calculated the critical stress σcr, at which the cortex was predicted to buckle locally, from the geometric properties and density of the cortical zone most highly loaded in a sideways fall. Using long‐established engineering principles, we estimated the amount by which stability or buckling resistance was increased by the trabecular bone supporting the most stressed cortical sector in each femoral neck. We repeated these measurements and calculations in an age‐ and sex‐matched series of femoral necks donated by women who had suffered intracapsular hip fracture and controls, using histological measurements of cortical thickness to improve accuracy. With normal aging, trabecular BMD declined asymmetrically, fastest in the supero‐lateral one‐half (in antero‐posterior projection) of the trabecular compartment. When viewed axially with respect to the femoral neck, the most rapid loss of trabecular bone occurred in the posterior part of this region (supero‐posterior S‐P), amounting to a 42% reduction in women (34% in men) over five decades of adult age. Because local cortical bone thickness declined comparably, age had no significant effect on the relative contributions of cortical and trabecular bone to elastic stability, and trabecular bone was calculated to contribute 40% (in men) and 43% (in women) to the S‐P cortex of its overall elastic stability. Hip fracture cases had reduced elastic stability compared with age‐matched controls, with a median reduction of 49% or 37%, depending on whether thickness was measured histologically or by CT (pQCT; p < 0.002 for both). This effect was because of reduced cortical thickness and density. Trabecular BMD was similar in hip fracture cases and controls. The capacity of the femur to resist fracture in a sideways fall becomes compromised with normal aging because cortical thickness and trabecular BMD in the most compressed part of the femoral neck both decline substantially. This decline is relatively more rapid than that of femoral neck areal BMD. If elastic instability rather than cortical crushing initiates the fracture event, interventions that increase trabecular bone in the proximal femur have great potential to reduce fracture risk because the gradient defining the increase in elastic stability with increasing trabecular BMD is steep, and most hip fracture cases have sufficient trabecular bone for anabolic therapies to build on.
Aims We evaluated pedometry as a novel patient-cen-tered outcome because it enables passive continuous assessment of activity and may provide information about the consequences of symptomatic ...toxicity complementary to self-report. Methods Adult patients undergoing hematopoietic cell transplant (HCT) wore pedometers and completed PRO assessments during transplant hospitalization (4 weeks) and 4 weeks post-discharge. Patient reports of symptomatic treatment toxicities (single items from PROCTCAE, http://healthcaredelivery. cancer.gov/pro-ctcae) and symptoms, physical health, mental health, and quality of life (PROMIS® Global-10, http://nih.promis.org), assessed weekly with 7-day recall on Likert scales, were compared individually with pedometry data, summarized as average daily steps per week, using linear mixed models. Results Thirty-two patients mean age 55 (SD = 14), 63 % male, 84 % white, 56 % autologous, 43 % allogeneic completed a mean 4.6 (SD = 1.5, range 1-8) evaluable assessments. Regression model coefficients (β) indicated within-person decrements in average daily steps were associated with increases in pain (β = –852; 852 fewer steps per unit increase in pain score, p < 0.001), fatigue (β = –886, p < 0.001), vomiting (β = –518, p < 0.01), shaking/chills (β = –587, p < 0.01), diarrhea (β = –719, p < 0.001), shortness of breath (β = –1018, p < 0.05), reduction in carrying out social activities (β = 705, p < 0.01) or physical activities (β = 618, p < 0.01), and global physical health (β = 101, p < 0.001), but not global mental health or quality of life. Conclusions In this small sample of HCT recipients, more severe symptoms, impaired physical health, and restrictions in the performance of usual daily activities were associated with statistically significant decrements in objectively measured daily steps. Pedometry may be a valuable outcome measure and validation anchor in clinical research.
The limited number of independent β-Sn grain orientations resulting from the difficulty in nucleating β-Sn during solidification of Sn-based solders has a large effect on the resulting β-Sn grain ...size and, hence, on overall solder joint performance and reliability. This study analyzes the efficacy of Ge as a heterogeneous nucleation agent for β-Sn by observing the morphologies and orientation relationships of as-deposited, solid-state annealed, and liquid-state annealed pure Sn films on single crystal Ge (100), (110), and (111) substrates. Results from scanning electron microscopy and electron backscatter diffraction showed that the as-deposited Sn films all deposited with a Sn (001)||
z
-axis texture, regardless of the underlying Ge substrate orientation. Solid-state annealing at 150 °C for 5 min did not result in significant dewetting of the Sn films, and the films maintained their as-deposited texture of Sn (001)||
z
-axis, regardless of the underlying Ge substrate orientation. Liquid-state annealing at 235 °C for 1 min resulted is large-scale dewetting of the Sn films and re-orientation of the Sn films on the various Ge substrates. After solidification, the Ge (100) and (110) single crystal substrates produced patches of dewetted grains of the same orientation but there were no consistent Sn grain textures after liquid-state annealing, suggesting no single orientation relationship. In contrast, solidification on Ge (111) single crystal substrates resulted in isolated grains with a single Sn film texture and an orientation relationship of
100
Sn
‖
111
Ge
and
100
Sn
‖
110
Ge
. Density Functional Theory simulations of the experimentally observed Ge (111) sample orientation relationship and the Ge/Sn cube-on-cube orientation relationship suggest favorable relative interfacial binding energies for both interface orientations.
Purpose
To investigate the effects of 60 min daily, short-term (STHA) and medium-term (MTHA) isothermic heat acclimation (HA) on the physiological and perceptual responses to exercise heat stress.
...Methods
Sixteen, ultra-endurance runners (female = 3) visited the laboratory on 13 occasions. A 45 min sub-maximal (40%
W
max
) cycling heat stress test (HST) was completed in the heat (40 °C, 50% relative humidity) on the first (HST
PRE
), seventh (HST
STHA
) and thirteenth (HST
MTHA
) visit. Participants completed 5 consecutive days of a 60 min isothermic HA protocol (target
T
re
38.5 °C) between HST
PRE
and HST
STHA
and 5 more between HST
STHA
and HST
MTHA
. Heart rate (HR), rectal (
T
re
), skin (
T
sk
) and mean body temperature (
T
body
), perceived exertion (RPE), thermal comfort (TC) and sensation (TS) were recorded every 5 min. During HSTs, cortisol was measured pre and post and expired air was collected at 15, 30 and 45 min.
Results
At rest,
T
re
and
T
body
were lower in HST
STHA
and HST
MTHA
compared to HST
PRE,
but resting HR was not different between trials. Mean exercising
T
re
,
T
sk
,
T
body
, and HR were lower in both HST
STHA
and HST
MTHA
compared to HST
PRE
. There were no differences between HST
STHA
and HST
MTHA
. Perceptual measurements were lowered by HA and further reduced during HST
MTHA
.
Conclusion
A 60 min a day isothermic STHA was successful at reducing physiological and perceptual strain experienced when exercising in the heat; however, MTHA offered a more complete adaptation.
The phenomenon of the ‘illness narrative’ is well-documented, in the last 25 years, of increasing interest to researchers in health and social sciences. Personal stories about the experience of ...facing the end of life also have an established history of particular relevance for palliative care clinicians. In this article, we review and describe a range of narrative analysis approaches that may be of use in palliative care. In particular, we distinguish between qualitative analysis applied to narratives and narrative analysis as a method. We discuss the potential benefits and challenges in the use of narrative research methods as a means to deepen our understanding of patient, carer and health professionals’ experience, and to support improvements in end of life care policy and practice.
The limited number of independent β-Sn grain orientations resulting from the difficulty in nucleating β-Sn during solidification of Sn-based solders has a large effect on the resulting β-Sn grain ...size and, hence, on overall solder joint performance and reliability. This study analyzes the efficacy of Ge as a heterogeneous nucleation agent for β-Sn by observing the morphologies and orientation relationships of as-deposited, solid-state annealed, and liquid-state annealed pure Sn films on single crystal Ge (100), (110), and (111) substrates. Here, the results from scanning electron microscopy and electron backscatter diffraction showed that the as-deposited Sn films all deposited with a Sn (001)|| z-axis texture, regardless of the underlying Ge substrate orientation. Solid-state annealing at 150 °C for 5 min did not result in significant dewetting of the Sn films, and the films maintained their as-deposited texture of Sn (001)|| z-axis, regardless of the underlying Ge substrate orientation. Liquid-state annealing at 235 °C for 1 min resulted is large-scale dewetting of the Sn films and re-orientation of the Sn films on the various Ge substrates. After solidification, the Ge (100) and (110) single crystal substrates produced patches of dewetted grains of the same orientation but there were no consistent Sn grain textures after liquid-state annealing, suggesting no single orientation relationship. In contrast, solidification on Ge (111) single crystal substrates resulted in isolated grains with a single Sn film texture and an orientation relationship of (100)Sn∥(111)Ge and 100Sn∥110Ge. Density Functional Theory simulations of the experimentally observed Ge (111) sample orientation relationship and the Ge/Sn cube-on-cube orientation relationship suggest favorable relative interfacial binding energies for both interface orientations.
Impaired cardiorespiratory fitness is associated with inferior survival in patients preparing to undergo hematopoietic cell transplantation (HCT). Exercise training based on short, higher intensity ...intervals has the potential to efficiently improve cardiorespiratory fitness. We studied home-based interval exercise training (IET) in 40 patients before autologous (N=20) or allogeneic (N=20) HCT. Each session consisted of five, 3 min intervals of walking, jogging or cycling at 65-95% maximal heart rate (MHR) with 3 min of low-intensity exercise (<65% MHR) between intervals. Participants were asked to perform sessions at least three times weekly. The duration of the intervention was at least 6 weeks, depending on each patient's scheduled transplantation date. Cardiorespiratory fitness was assessed from a peak oxygen consumption test (VO2peak) and a 6 min walk (6MWD) before and after the intervention period. For the autologous HCT cohort, improvements in VO2peak (P=0.12) and 6MWD (P=0.19) were not statistically significant. For the allogeneic cohort, the median VO2peak improvement was 3.7 ml/kg min (P=0.005) and the median 6MWD improvement was 34 m (P=0.006). Home-based IET can be performed before HCT and has the potential to improve cardiorespiratory fitness.
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