Relative impact of channel symbol rate on transmission capacity

Through C+L band transmission experiments and theoretical modeling, we investigate the impact of channel symbol rate (30, 40, 60, and 85 GBd) on the performance of data center interconnection, metropolitan, and core network distances. Two different transponder architectures are investigated: (a) single-carrier receiver and (b) multi-carrier receiver, where multiple subcarriers are received together in a single wideband receiver. The architectures of both receivers experience a reduction in the achievable information rate as the channel symbol rate increases due to dominating transceiver noise; this holds over all tested transmission distances. However, the multi-carrier receiver shows a weaker performance dependency on symbol rate, as receiver-related impairments dominate. When testing the single-carrier receiver after 630 km, we find that by increasing the channel symbol rate from 40 to 85 GBd, gross capacity decreases by 16%; however, the required number of transceivers to fill the transmission window decreases by 52%. Using the multi-carrier receiver reduces receiver count further. This potentially impacts the cost and complexity of deploying fully loaded transmission systems

74.38 Tb/s Transmission Over 6300 km Single Mode Fibre Enabled by C plus L Amplification and Geometrically Shaped PDM-64QAM

Ultrawide-bandwidth optical amplification over almost 90 nm, covering the C+L bands, is described. Complemented by system-tailored geometrical constellation shaping and nonlinearity compensation, it enabled a record capacity transmission of 74.38 Tb/s over 6,300 km of G.654 single-mode fibre. The hybrid scheme, combining backward Raman pre-amplification with EDFA, significantly improves the average effective noise figure across the entire bandwidth, allowing the use of span lengths of 70 km. The system-tailored GS-64QAM constellation was optimised to both linear link impairments and transceiver nonlinearities, improving the gap to the AWGN channel capacity relative to square 64QAM from 0.6 bit/symbol to 0.35 bit/symbol. We experimentally evaluated the system performance using the bit-wise achievable information rate (AIR) and signal-to-noise ratio (SNR) at the end of transmission, as well as post SD-FEC BER

Duration of palliative care before death in international routine practice: A systematic review and meta-analysis

Background: Early provision of palliative care, at least 3-4 months before death, can improve patient quality of life and reduce burdensome treatments and financial costs. However, there is wide variation in duration of palliative care received before death reported across the research literature. This study aims to determine the duration of time from initiation of palliative care to death for adults receiving palliative care across the international literature. Methods: We conducted a systematic review and meta-analysis that was registered with PROSPERO (CRD42018094718). Six databases were searched for articles published between Jan 1st 2013 and Dec 31st 2018: MEDLINE; Embase; CINAHL; Global Health, Web of Science; and The Cochrane Library, as well undertaking citation list searches. Following PRISMA guidelines, articles were screened using inclusion (any study design reporting duration from initiation to death in adults palliative care services) and exclusion (paediatric/non-English language studies, trials influencing the timing of palliative care) criteria. Quality appraisal was completed using Hawker’s criteria and the main outcome was duration of palliative care (median/mean days from initiation to death). Results: 169 studies from 23 countries were included, involving 11,996,479 patients. Prior to death, the median duration from initiation of palliative care to death was 18·9 days (IQR 0·1), weighted by the number of participants. Significant differences between duration were found by disease type (15 days for cancer vs 6 days for non-cancer conditions), service type (19 days for specialist palliative care unit, 20 days for community/home care, and 6 days for general hospital ward) and development index of countries (18.91 days for very high development vs 34 days for all other levels of development). 43% of studies were rated as ‘good’ quality. Limitations include a preponderance of data from high-income countries, with unclear implications for low- and middle-income countries. Conclusions: Duration of palliative care is much shorter than the 3-4 months of input by a multidisciplinary team necessary in order for the full benefits of palliative care to be realised. Furthermore, the findings highlight inequity in access across patient, service and country characteristics. We welcome more consistent terminology and methodology in the assessment of duration of palliative care from all countries, including from less-developed settings, to inform benchmarking, service evaluation and quality improvement

Endocannabinoids Generated by Ca2+ or by Metabotropic Glutamate Receptors Appear to Arise from Different Pools of Diacylglycerol Lipase

The identity and subcellular sources of endocannabinoids (eCBs) will shape their ability to affect synaptic transmission and, ultimately, behavior. Recent discoveries support the conclusion that 2-arachidonoyl glycerol, 2-AG, is the major signaling eCB, however, some important issues remain open. 2-AG can be synthesized by a mechanism that is strictly Ca2+-dependent, and another that is initiated by G-protein coupled receptors (GPCRs) and facilitated by Ca2+. An important question is whether or not the 2-AG in these cases is synthesized by the same pool of diacylglycerol lipase alpha (DAGLα). Using whole-cell voltage-clamp techniques in CA1 pyramidal cells in acute in vitro rat hippocampal slices, we investigated two mechanistically distinct eCB-mediated responses to address this issue. We now report that pharmacological inhibitors of DGLα have quantitatively different effects on eCB-mediated responses triggered by different stimuli, suggesting that functional, and perhaps physical, distinctions among pools of DAGLα exist

The Calcitonin and Glucocorticoids Combination: Mechanistic Insights into Their Class-Effect Synergy in Experimental Arthritis

PMCID: PMC3564948This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

74.38 Tb/s Transmission over 6300 km Single Mode Fiber with Hybrid EDFA/Raman Amplifiers

Transmission of 306×35 GBd, dual polarization, 64-ary geometrically shaped channels over 90×70 km of SMF was demonstrated, achieving a net throughput of 74.38 Tb/s. A combination of hybrid fiber spans and EDFA/Raman amplifiers enabled a continuous gain bandwidth of 10.8 THz

Expression of interleukin 6 (IL-6) correlates with oestrogen receptor in human breast carcinoma

Multifunctional cytokines play important and only partially defined roles in mammary tumour development and progression. Normal human mammary epithelial cells constitutively produce interleukin 6 (IL-6), IL-8 and a non-secreted form of tumour necrosis factor. Transformation of mammary epithelial cells by different oncogenes is frequently associated with alterations of cytokine/growth factor production and responsiveness. In the present study we analysed the expression of IL-6 in 149 cases of invasive breast carcinoma and the data have been correlated with clinico-pathological variables including tumour size, histological grade, nodal status, and oestrogen and progesterone receptors, Ki67 and p53, protein expression. Though the majority of breast carcinomas expressed at least low levels of immunoreactive IL-6, we found that expression of this cytokine was inversely associated with histological tumour grade (P = 0.0017), but not with tumour size and nodal status. Ki67 positivity was inversely correlated with IL-6 expression (P = 0.027). Among biological parameters analysed, a direct association was found between the percentage of IL-6-positive cells and that of oestrogen (P = 0.00005) and progesterone (P = 0.025) receptor-positive cells. No correlation was observed between IL-6 and p53 protein expression. These data indicate that down regulation of IL-6 is associated with highly malignant mammary carcinomas. It will be of interest to evaluate whether alterations of cytokines that are constitutively produced by mammary cells are also associated with high-grade tumours

Study on the Impact of Nonlinearity and Noise on the Performance of High-Capacity Broadband Hybrid Raman-EDFA Amplified System

We experimentally demonstrated the transmission of 312 × 35 GBd DP-256QAM over 9 × 70 km spans using hybrid distributed Raman-EDFA (HRE) amplifiers with a continuous 91 nm gain bandwidth. A total throughput of 120 Tbit/s over 630 km is demonstrated, with a net achievable information rate after SD-FEC of 10.99 bit/symbol. We further perform an exten- sive, theoretical assessment of the noise contributions originating from amplifier, transceiver sub-system and fiber nonlinearity using the Gaussian noise model in the presence of inter-channel stimulated Raman scattering (ISRS GN model). The ISRS GN model accounts for arbitrary, wavelength dependent signal power profiles along fiber spans, which is vital for the modeling of ultra- wideband transmission, particularly for hybrid Raman-amplified links. It is found that, due to the low noise HRE amplifier and a transmission distance of 630 km, the noise originating from the transceiver sub-system imposed a penalty of 5 dB in SNR. The transceiver noise is, therefore, the major performance bottleneck and the main limitation of the system throughput