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- Özdogan, Özgecan, et al.
(författare)
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Downlink Performance of Cell-Free Massive MIMO with Rician Fading and Phase Shifts
- 2019
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Ingår i: 2019 IEEE 20th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538665282
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Konferensbidrag (refereegranskat)abstract
- In this paper, we study the downlink (DL) spectral efficiency (SE) of a cell-free massive multiple-input-multiple-output (MIMO) system with Rician fading channels. The phase of the line-of-sight (LoS) path is modeled as a uniformly distributed random variable to take the phase-shifts due to mobility and phase noise into account. Considering the availability of prior information at the access points (APs), the phase-aware minimum mean square error (MMSE) and non-aware linear MMSE (LMMSE) estimators are derived. The MMSE estimator requires perfectly estimated phase knowledge whereas the LMMSE is derived without it. Besides, two different transmission modes are studied: coherent and non-coherent. Closed-form DL SE expressions for both coherent and non-coherent transmission with maximum-ratio (MR) precoding are derived for the two estimators. Numerical results show that the performance loss due to the lack of phase information is small and coherent transmission mode performs much better than non-coherent transmission.
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| 2. |
- Aad, G., et al.
(författare)
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- 2011
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Ahmad, T., et al.
(författare)
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Frequency and outcomes of undiagnosed diabetes mellitus in patients presenting with acute myocardial infarction
- 2020
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Ingår i: Medical Forum Monthly. - : Medical Forum Monthly. - 1029-385X. ; 31:12, s. 3-7
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To find out frequency and outcomes of undiagnosed diabetes mellitus in patients presenting with acute ST elevation myocardial infarction (STEMI). Study Design: Descriptive / Cross-Sectional Study Place and Duration of study: This study was conducted at the Cardiology Department, Lady Reading Hospital, Peshawar from November 2018 to May 2019. Materials and Methods: Patient of either gender having age ranging between 30-75 years old with acute STEMI who present within 12 hours of symptoms and with no past history of documented diabetes mellitus were included in the study. Venous blood samples for laboratory data, including random blood sugar, two fasting blood sugar and HBA1c using hitachi modular evo p800 machine was done. Results: A total of 158 patients having acute STEMI were studied. Males were 68.4% (n=108).The mean age was 59.65 ±10.80 years. Frequency of undiagnosed diabetes mellitus was 31.64 % (n = 50). In non-diabetics stress hyperglycemia was found in 51.85 % (n=56) patients. Among various types of STEMI, anterior STEMI was more common presentation 34.1 % (n=54. p= 0.85). Mean HBA1C was 6.19 ± 1.87%. Frequency of Ventricular tachycardia (VT) was 22.2 % in which undiagnosed diabetics were n=18 (p=0.004).Ventricular fibrillation was present in 13.3 % patients with undiagnosed diabetics were n=14 (p=0.001). Frequency of AF was 13.9% (n=22) with undiagnosed diabetics having AF in n=13 (p=0.003). SVT was present in 5.7% (n=9) patients with not significant difference between two groups (p=0.017). Among various mechanical complications VSR was present in 10 % (n=16) of patients (p=0.001), cardiogenic shock in 11.1 % (n=18) patients (p=0.004), acute LVF was present in 15.8 % patients (p=0.017). Conclusion: In our study we concluded that one third of patients having acute ST elevation myocardial infarction have undiagnosed diabetes mellitus (31.64 %, n = 50). The most common complication was ventricular tachycardia among electrical complication and LVF among mechanical complication.
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| 8. |
- Ahmad, T, et al.
(författare)
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Skeletal changes in type-2 diabetic Goto-Kakizaki rats.
- 2003
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Ingår i: The Journal of endocrinology. - : Bioscientifica. - 0022-0795 .- 1479-6805. ; 178:1, s. 111-6
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Tidskriftsartikel (refereegranskat)abstract
- We characterized appendicular and axial bones in rats with type-2 diabetes in five female Goto-Kakizaki (GK) rats, a strain developed from the Wistar rat showing spontaneous type-2 diabetes, and five age- and sex-matched non-diabetic Wistar rats. The humerus, tibia, metatarsals and vertebral bodies were analysed by peripheral quantitative computerized tomography (pQCT). In diabetic rats, the height of the vertebral bodies and length of the humerus were decreased while the length of the metatarsals was increased. A decreased cross-sectional area was found in the vertebral end-plate region and the tibial metaphysis. Notably, the diaphysis in all long bones showed expansion of periosteal and endosteal circumference. In tibia this resulted in increased cortical thickness, whereas in humerus and metatarsal it was unchanged. Areal moment of inertia was increased in all diaphyses suggesting greater bending strength. The most conspicuous finding in diabetic rats pertained to trabecular osteopenia. Thus, trabecular bone mineral density was significantly reduced in all bones examined, by 33-53%. Our pQCT study of axial and appendicular bones suggests that the typical feature of diabetic osteopathy in the GK rat is loss of trabecular bone and expansion of the diaphysis. The loss of metaphyseal trabecular bone if also present in diabetic patients may prove to underlie the susceptibility to periarticular fracture and Charcot arthropathy. The findings suggest that the risk of fracture in diabetes varies according to the specific sub-regions of a bone. The approach described may prove to be useful in the early detection of osteopathy in diabetic patients who may be amenable to preventive treatment.
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