A Damage Mechanics Approach to Fatigue Assessment in Offshore Structures

This article is intended to describe the development of a fatigue damage model capable of assessing fatigue damage in offshore structures. This is achieved by for mulating a set of damage coupled constitutive and evolution equations which make the for mulation of a unified approach possible under both low and high cycle fatigue damage and consistent with the structural dynamic response of the changing/deteriorating material be haviors. The structural analysis for the whole designed period, say about 30 years, can be carried out with the aid of the proposed analytical procedure, in which the fundamental characteristics of sea wave statistics responsible for the structural dynamic response can be sufficiently considered. An offshore structure subject to complex ocean environment is described by a general stochastic system which embeds a group of stochastic subsystems, each characterizing a duty cycle. An effective analytical method is established by introduc ing the concept of duty strain range with a clear mathematical definition and its analytical solution which covers all possible spectral parameters. The history-dependent damage is also included in the damage model so that the overload effects can be analyzed. It should be pointed out that the whole procedure can be fully computerized such that the practical or engineering significance of varying design variables can be readily highlighted.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67255/2/10.1177_105678959300200405.pd

Trajectory of functional outcome and health status after moderate-to-major trauma in Hong Kong: A prospective 5 year cohort study

Background Trauma care systems in Asia have been developing in recent years, but there has been little long-term outcome data from injured survivors. This study aims to evaluate the trajectory of functional outcome and health status up to five years after moderate to major trauma in Hong Kong. Methods We report the five year follow up results of a multicentre, prospective cohort from the trauma registries of three regional trauma centres in Hong Kong. The original cohort recruited 400 adult trauma patients with ISS ≥ 9. Telephone follow up was conducted longitudinally at seven time points, and the extended Glasgow Outcome Scale (GOSE) and Short-Form 36 (SF36) were tracked. Results 119 out of 309 surviving patients (39%) completed follow up after 5 years. The trajectory of GOSE, PCS and MCS showed gradual improvements over the seven time points. 56/119 (47.1%) patients reported a GOSE = 8 (upper good recovery), and the mean PCS and MCS was 47.8 (95% CI 45.8, 49.9) and 55.8 (95% CI 54.1, 57.5) respectively at five years. Univariate logistic regression showed change in PCS - baseline to 1 year and 1 year to 2 years, and change in MCS - baseline to 1 year were associated with GOSE = 8 at 5 years. Linear mixed effects model showed differences in PCS and MCS were greatest between 1-month and 6-month follow up. Conclusions After injury, the most rapid improvement in PCS and MCS occurred in the first six to 12 months, but further recovery was still evident for MCS in patients aged under 65 years for up to five years

Post hoc analysis of the SONAR trial indicates that the endothelin receptor antagonist atrasentan is associated with less pain in patients with type 2 diabetes and chronic kidney disease

Pain is prevalent among patients with diabetes and chronic kidney disease (CKD). The management of chronic pain in these patients is limited by nephrotoxicity of commonly used drugs including non-steroidal anti-inflammatory drugs (NSAIDs) and opioids. Since previous studies implicated endothelin-1 in pain nociception, our post hoc analysis of the SONAR trial assessed the association between the endothelin receptor antagonist atrasentan and pain and prescription of analgesics. SONAR was a randomized, double-blind, placebo-controlled clinical trial that recruited participants with type 2 diabetes and CKD (estimated glomerular filtration rate 25–75 ml/min/1.73 m2; urinary albumin-to-creatinine ratio 300–5000 mg/g). Participants were randomized to receive atrasentan or placebo (1834 each arm). The main outcome was pain-related adverse events (AEs) reported by investigators. We applied Cox regression to assess the effect of atrasentan compared to placebo on the risk of the first reported pain-related AE and, secondly, first prescription of analgesics. We used the Anderson-Gill method to assess effects on all (first and subsequent) pain-related AEs. During 2.2-year median follow-up, 1183 pain-related AEs occurred. Rates for the first pain-related event were 138.2 and 170.2 per 1000 person-years in the atrasentan and placebo group respectively (hazard ratio 0.82 [95% confidence interval 0.72–0.93]). Atrasentan also reduced the rate of all (first and subsequent) pain-related AEs (rate ratio 0.80 [0.70-0.91]). These findings were similar after accounting for competing risk of death (sub-hazard ratio 0.81 [0.71–0.92]). Patients treated with atrasentan initiated fewer analgesics including NSAIDs and opioids compared to placebo during follow-up (hazard ratio = 0.72 [0.60–0.88]). Thus, atrasentan was associated with reduced pain-related events and pain-related use of analgesics in carefully selected patients with type 2 diabetes and CKD

Post hoc analysis of the SONAR trial indicates that the endothelin receptor antagonist atrasentan is associated with less pain in patients with type 2 diabetes and chronic kidney disease

Pain is prevalent among patients with diabetes and chronic kidney disease (CKD). The management of chronic pain in these patients is limited by nephrotoxicity of commonly used drugs including non-steroidal anti-inflammatory drugs (NSAIDs) and opioids. Since previous studies implicated endothelin-1 in pain nociception, our post hoc analysis of the SONAR trial assessed the association between the endothelin receptor antagonist atrasentan and pain and prescription of analgesics. SONAR was a randomized, double-blind, placebo-controlled clinical trial that recruited participants with type 2 diabetes and CKD (estimated glomerular filtration rate 25–75 ml/min/1.73 m2; urinary albumin-to-creatinine ratio 300–5000 mg/g). Participants were randomized to receive atrasentan or placebo (1834 each arm). The main outcome was pain-related adverse events (AEs) reported by investigators. We applied Cox regression to assess the effect of atrasentan compared to placebo on the risk of the first reported pain-related AE and, secondly, first prescription of analgesics. We used the Anderson-Gill method to assess effects on all (first and subsequent) pain-related AEs. During 2.2-year median follow-up, 1183 pain-related AEs occurred. Rates for the first pain-related event were 138.2 and 170.2 per 1000 person-years in the atrasentan and placebo group respectively (hazard ratio 0.82 [95% confidence interval 0.72–0.93]). Atrasentan also reduced the rate of all (first and subsequent) pain-related AEs (rate ratio 0.80 [0.70-0.91]). These findings were similar after accounting for competing risk of death (sub-hazard ratio 0.81 [0.71–0.92]). Patients treated with atrasentan initiated fewer analgesics including NSAIDs and opioids compared to placebo during follow-up (hazard ratio = 0.72 [0.60–0.88]). Thus, atrasentan was associated with reduced pain-related events and pain-related use of analgesics in carefully selected patients with type 2 diabetes and CKD

Post hoc analysis of the SONAR trial indicates that the endothelin receptor antagonist atrasentan is associated with less pain in patients with type 2 diabetes and chronic kidney disease

Pain is prevalent among patients with diabetes and chronic kidney disease (CKD). The management of chronic pain in these patients is limited by nephrotoxicity of commonly used drugs including non-steroidal anti-inflammatory drugs (NSAIDs) and opioids. Since previous studies implicated endothelin-1 in pain nociception, our post hoc analysis of the SONAR trial assessed the association between the endothelin receptor antagonist atrasentan and pain and prescription of analgesics. SONAR was a randomized, double-blind, placebo-controlled clinical trial that recruited participants with type 2 diabetes and CKD (estimated glomerular filtration rate 25–75 ml/min/1.73 m2; urinary albumin-to-creatinine ratio 300–5000 mg/g). Participants were randomized to receive atrasentan or placebo (1834 each arm). The main outcome was pain-related adverse events (AEs) reported by investigators. We applied Cox regression to assess the effect of atrasentan compared to placebo on the risk of the first reported pain-related AE and, secondly, first prescription of analgesics. We used the Anderson-Gill method to assess effects on all (first and subsequent) pain-related AEs. During 2.2-year median follow-up, 1183 pain-related AEs occurred. Rates for the first pain-related event were 138.2 and 170.2 per 1000 person-years in the atrasentan and placebo group respectively (hazard ratio 0.82 [95% confidence interval 0.72–0.93]). Atrasentan also reduced the rate of all (first and subsequent) pain-related AEs (rate ratio 0.80 [0.70-0.91]). These findings were similar after accounting for competing risk of death (sub-hazard ratio 0.81 [0.71–0.92]). Patients treated with atrasentan initiated fewer analgesics including NSAIDs and opioids compared to placebo during follow-up (hazard ratio = 0.72 [0.60–0.88]). Thus, atrasentan was associated with reduced pain-related events and pain-related use of analgesics in carefully selected patients with type 2 diabetes and CKD

Post hoc analysis of the SONAR trial indicates that the endothelin receptor antagonist atrasentan is associated with less pain in patients with type 2 diabetes and chronic kidney disease

Pain is prevalent among patients with diabetes and chronic kidney disease (CKD). The management of chronic pain in these patients is limited by nephrotoxicity of commonly used drugs including non-steroidal anti-inflammatory drugs (NSAIDs) and opioids. Since previous studies implicated endothelin-1 in pain nociception, our post hoc analysis of the SONAR trial assessed the association between the endothelin receptor antagonist atrasentan and pain and prescription of analgesics. SONAR was a randomized, double-blind, placebo-controlled clinical trial that recruited participants with type 2 diabetes and CKD (estimated glomerular filtration rate 25–75 ml/min/1.73 m2; urinary albumin-to-creatinine ratio 300–5000 mg/g). Participants were randomized to receive atrasentan or placebo (1834 each arm). The main outcome was pain-related adverse events (AEs) reported by investigators. We applied Cox regression to assess the effect of atrasentan compared to placebo on the risk of the first reported pain-related AE and, secondly, first prescription of analgesics. We used the Anderson-Gill method to assess effects on all (first and subsequent) pain-related AEs. During 2.2-year median follow-up, 1183 pain-related AEs occurred. Rates for the first pain-related event were 138.2 and 170.2 per 1000 person-years in the atrasentan and placebo group respectively (hazard ratio 0.82 [95% confidence interval 0.72–0.93]). Atrasentan also reduced the rate of all (first and subsequent) pain-related AEs (rate ratio 0.80 [0.70-0.91]). These findings were similar after accounting for competing risk of death (sub-hazard ratio 0.81 [0.71–0.92]). Patients treated with atrasentan initiated fewer analgesics including NSAIDs and opioids compared to placebo during follow-up (hazard ratio = 0.72 [0.60–0.88]). Thus, atrasentan was associated with reduced pain-related events and pain-related use of analgesics in carefully selected patients with type 2 diabetes and CKD