A LTE MIMO OTA Test System Using Vector Signal Transceivers

A 2 × 2 multiple-input-multiple-output over-the-air (MIMO OTA) test system based on four field-programmable Vector-Signal-Transceiver (VST) modules is presented. The system enables 2 x 2 MIMO OTA testing by assembling of a twochannel Evolved Node B (eNodeB) LTE base station emulator, a 2x2 channel emulator, and a two-channel user equipment (UE) simulator. A two-stage MIMO OTA test method has been demonstrated with downlink Long-Term Evolution Time-Division Duplex (LTE-TDD) mode using different modulation and coding schemes (MCSs). Test results and analysis are shown. This system will allow a systematic study of MIMO OTA metrology needs

Metrology for RF-exposure from massive MIMO system

Chapter Contents:21.1 Motivation for 5G RF-exposure new metrology and guidelines21.2 Measuring 5G RF-exposure21.3 Experimental assessment of the RF-exposure of massive MIMO base station via a reconfigurable testbed21.3.1 mMIMO testbed set-up21.3.2 Calibration of the mMIMO testbed equipment21.3.3 Experimental set-up and test scenarios21.3.4 First experiment21.3.5 Second experiment21.4 SummaryReference

Flow cytometric cell sorting and in vitro pre-osteoinduction are not requirements for in vivo bone formation by human adipose-derived stromal cells.

Human adipose-derived stromal cells (hASCs) are a promising cell source for bone tissue engineering. However, before the clinical application of hASCs for the treatment of bone defects, key questions require answers, including whether pre-osteoinduction (OI) and flow cytometric cell purification are indispensible steps for in vivo bone formation by hASCs. In this study, hASCs were purified by flow cytometric cell sorting (FCCS). The osteogenic capabilities of hASCs and purified hASCs with or without pre-osteoinduction were examined through in vitro and in vivo experiments. We found that pre-OI enhanced the in vitro osteogenic capacity of hASCs. However, 8 weeks after in vivo implantation, there were no significant differences between hASCs and hASCs that had undergone OI (hASCs+OI) or between purified hASCs and purified hASCs+OI (P>0.05). Interestingly, we also found that purified hASCs had an osteogenic potential similar to that of unpurified hASCs in vitro and in vivo. These results suggest that FCCS and in vitro pre-OI are not requirements for in vivo bone formation by hASCs

Passaged human adipose-derived stromal cells (hASCs) express mesenchymal stem cell (MSC)-specific surface markers.

<p>hASCs of the third passage (P3) expressed the MSC-specific surface markers CD44, CD73, CD90 and CD105, but did not express CD45 or HLA-DR, which are hematopoietic cell-specific markers. Isotype controls (Iso) were used in all flow cytometry experiments.</p

Growth curves for human adipose-derived stromal cells (hASCs) and purified hASCs.

<p>There were no significant differences in the proliferative capacities of the two cell types during day 1 (d1) to day 6 (d6) (<i>P</i>>0.05).</p

Osteogenic potential of human adipose-derived stromal cells (hASCs) and purified hASCs <i>in vitro</i>.

<p>A) hASCs and purified hASCs stained positive for alkaline phosphatase (ALP) after 7 days of osteoinduction (OI). The scale bar represents 100 µm. B) hASCs and purified hASCs were positive for Alizarin Red staining after 14 days of OI. The scale bar represents 100 µm. C) The ALP activities of hASCs, purified hASCs and hBMMSCs were significantly elevated after 7 days of OI; however, the ALP activities of both hASCs and purified hASCs were significantly lower than that of hBMMSCs (<i>P</i><0.05). There were no significant differences between hASCs and purified hASCs or between hASCs+OI and purified hASCs+OI. D) The mineralization activities of hASCs, purified hASCs and hBMMSCs were significantly increased after 14 days of OI. There were no significant differences between hASCs and purified hASCs or between hASCs+OI and purified hASCs+OI. ^*<i>P</i><0.05 compared with hASCs without OI; ^**<i>P</i><0.05 compared with purified hASCs without OI; ^***<i>P</i><0.05 compared with hBMMSCs without OI; ^#<i>P</i><0.05 compared with hBMMSCs after 7 days of OI.</p

<i>In vivo</i> bone formation by human adipose-derived stromal cells (hASCs).

<p>A) Gross observation and soft X-ray examination showed that hASCs, purified hASCs, hASCs that had undergone osteoinduction (OI) (hASCs+OI) and purified hASCs+OI formed bone-like tissues of relatively higher density than blank controls and fibroblast controls. B) Hematoxylin and eosin staining showed bone-like tissues with the typical structure of osteocyte lacunae in all four groups 4 weeks after implantation. The scale bar represents 50 µm. C) Eight weeks after implantation, the area of bone formation was larger in all four groups. The scale bar represents 50 µm. D) Quantitative measurements of bone-like tissues demonstrated that, 4 weeks after implantation, the area of bone formation was significantly increased in hASCs+OI and purified hASCs+OI compared with hASCs and purified hASCs without OI. However, 8 weeks after implantation there were no significant differences among the four groups. ^*<i>P</i><0.05 compared with hASCs without OI; ^#<i>P</i><0.05 compared with purified hASCs without OI.</p

Osteogenesis-associated gene expression and protein secretion by human adipose-derived stromal cells (hASCs) and purified hASCs.

<p>A) There were no significant differences in the mRNA levels of Runt related transcription factor 2 (RUNX2), Osterix (OSX), Type I Collagen (COL1A1) or Osteocalcin (OCN) between hASCs and purified hASCs at 3, 7 or 14 days after osteogenic induction (<i>P</i>>0.05). B) There was no significant difference in OCN secretion between hASCs and purified hASCs at 24, 48 or 72 hours after osteogenic induction (<i>P</i>>0.05).</p