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To ensure frequency stability in future low-inertia power grids, fast ancillary services such as fast frequency reserves (FFR) have been proposed. In this work, the coordination of conventional (slow) frequency containment reserves (FCR) with FFR is treated as a decentralized model matching problem. The design results in a dynamic virtual power plant (DVPP) whose aggregated output fulfills the system operator’s (SO’s) requirements in all time scales, while accounting for the capacity and bandwidth limitation of participating devices. This is illustrated in a 5-machine representation of the Nordic synchronous grid. In the Nordic grid, stability issues and bandwidth limitations associated with non-minimum phase zeros of hydropower is a well-known problem. By simulating the disconnection of a 1400 MW importing dc link, it is shown that the proposed DVPP design allows for coordinating fast FFR from wind, with slow FCR from hydro, while respecting dynamic limitations of all participating devices. The SO’s requirements are fulfilled in a realistic low-inertia scenario without the need to install battery storage or to waste wind energy by curtailing the wind turbines., QC 20230328

BACKGROUND: The WHO and the World Bank ask countries to report the national volume of surgery. This report describes these data for Sweden, a high-income country. METHODS: In an 8-year population-based observational cohort study, all inpatient and outpatient care in the public and private sectors was detected in the Swedish National Patient Register and screened for the occurrence of surgery. The entire Swedish population was eligible for inclusion. All patients attending healthcare for any disease were included. Incidence rates of surgery and likelihood of surgery were calculated, with trends over time, and correlation with sex, age and disease category. RESULTS: Almost one in three hospitalizations involved a surgical procedure (30·6 per cent). The incidence rate of surgery exceeded 17 480 operations per 100 000 person-years, and at least 58·5 per cent of all surgery was performed in an outpatient setting (range 58·5 to 71·6 per cent). Incidence rates of surgery increased every year by 5·2 (95 per cent c.i. 4·2 to 6·1) per cent (P < 0·001), predominantly owing to more outpatient surgery. Women had a 9·8 (95 per cent c.i. 5·6 to 14·0) per cent higher adjusted incidence rate of surgery than men (P < 0·001), mainly explained by more surgery during their fertile years. Incidence rates peaked in the elderly for both women and men, and varied between disease categories. CONCLUSION: Population requirements for surgery are greater than previously reported, and more than half of all surgery is performed in outpatient settings. Distributions of age, sex and disease influence estimates of population surgical demand, and should be accounted for in future global and national projections of surgical public health needs.

BackgroundRescue therapy with infliximab (IFX) has been proven effective in a steroid-refractory attack of ulcerative colitis (UC). The long-term efficacy is not well described. AimTo present a retrospective study of IFX as rescue therapy in UC. Primary end points were colectomy-free survival at 3 and 12months. MethodsIn this multicentre study, 211 adult patients hospitalised between 1999 and 2010 received IFX 5mg/kg as rescue therapy due to a steroid-refractory, moderate-to-severe attack of UC. Exclusion criteria were duration of current flare for >12weeks, corticosteroid treatment for >8weeks before hospitalisation, previous IFX therapy or Crohn's disease. ResultsProbability of colectomy-free survival at 3months was 0.71 (95% CI, 0.64-0.77), at 12months 0.64 (95% CI, 0.57-0.70), at 3years 0.59 (95% CI, 0.52-0.66) and at 5years 0.53 (95% CI, 0.44-0.61). Steroid-free, clinical remission was achieved in 105/211 (50%) and 112/209 (54%) patients at 3 and 12months respectively. Of 75 colectomies during the first year, 48 (64%) were carried out during the first 14days, 13 (17%) on days 15-90 and 14 (19%) between 3 and 12months. There were three (1.4%) deaths during the first 3months. ConclusionsInfliximab is an effective rescue treatment, both short- and long-term, in a steroid-refractory attack of UC. Most IFX failures underwent surgery during the first 14days, which calls for studies on how to optimise induction treatment with IFX. Serious complications, including mortality, were rare.

We present a computational screening study of ternary metal borohydrides for reversible hydrogen storage based on density functional theory. We investigate the stability and decomposition of alloys containing 1 alkali metal atom, Li, Na, or K (M1); and 1 alkali, alkaline earth or 3d/4d transition metal atom (M2) plus two to five (BH4)− groups, i.e., M1M2(BH4)2–5, using a number of model structures with trigonal, tetrahedral, octahedral, and free coordination of the metal borohydride complexes. Of the over 700 investigated structures, about 20 were predicted to form potentially stable alloys with promising decomposition energies. The M1(Al/Mn/Fe)(BH4)4, (Li/Na)Zn(BH4)3, and (Na/K)(Ni/Co)(BH4)3 alloys are found to be the most promising, followed by selected M1(Nb/Rh)(BH4)4 alloys

Udgivelsesdato: 2008-Sep, PURPOSE: The risk of rectal cancer after colectomy and ileorectal anastomosis may be reduced in the last decades, as patients with severe polyposis now have an ileoanal pouch. We have reevaluated the risk of rectal cancer and proctectomy for all causes according to the year of operation. METHODS: On the basis of the year of operation in 776 patients with ileorectal anastomosis and 471 pouch patients in Denmark, Finland, Holland, and Sweden, the "pouch period" was defined to start in 1990. Ileorectal anastomosis follow-up data was captured by May 31, 2006. The cumulative risk of rectal cancer and proctectomy was compared before and after 1990 by Kaplan-Meier analysis. RESULTS: In the prepouch period 56/576 patients (10 percent) developed rectal cancer, vs. 4/200 (2 percent) in the pouch period. Neither the cumulative risk of rectal cancer (p = 0.07) nor the cumulative risk of proctectomy (p = 0.17) changed. However, in females the cumulative risk of rectal cancer (p = 0.04) and of proctectomy (p = 0.03) were lower in the pouch period. CONCLUSIONS: Since the introduction of the ileoanal pouch rectal cancer has decreased after ileorectal anastomosis, but only statistically significant in females. This indicates that ileorectal anastomosis may still be justified in selected patients with mild adenomatosis, especially in young females.