Inadequate secretion of vasopressin during fluid removal by hemodialysis may contribute to the cardiovascular instability that complicates this therapy and administration of exogenous hormone, by supporting arterial pressure, may facilitate volume removal. To test this, we measured plasma vasopressin in patients with end-stage renal disease (ESRD) during hemodialysis and found that despite significant fluid removal, plasma vasopressin concentration did not increase. We further found that ESRD did not alter the endogenous removal rate of plasma vasopressin and that plasma hormone is not dialyzed. Finally, in a randomized, double-blinded, placebo-controlled trial in 22 hypertensive patients, we examined the effect of a constant infusion of a non-pressor dose of vasopressin on the arterial pressure response during a hemodialysis in which the target fluid loss was increased by 0.5 kg over the baseline prescription. We found that arterial pressure was more stable in the patients receiving vasopressin and that while only one patient (9%) in the vasopressin group had a symptomatic hypotensive episode, 64% of the patients receiving placebo had such an episode (P=0.024). Moreover, increased fluid removal was achieved only in the vasopressin group (520+/-90 ml vs 64+/-130 ml, P=0.01). Thus, administration of non-pressor doses of vasopressin to hypertensive subjects improves cardiovascular stability during hemodialysis and allows increased removal of excess extracellular fluid. Inadequate vasopressin secretion during hemodialysis-induced fluid removal is a likely contributor to the intradialytic hypotension that limits fluid removal.

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The W-band (92 -95 GHz) Traveling Wave Tube enabling the first Point to multipoint millimeter wave backhaul wireless network is in final phase of fabrication. The challenge is to build a TWT suitable for large volume fabrication to satisfy the cost constraints of network operators. Performances are targeted to provide coverage on sectors up to 90° with 1 km range. Simulations demonstrate a bandwidth of operation in excess of 5 GHz with a saturated output power of 40 W. The TWT is directly connected to a sector horn antenna.

Point to multipoint (PmP) distribution at millimeter wave is a frontier so far not yet crossed due to the formidable technological challenge that the high atmospheric attenuation poses. The transmission power at level of tens of Watts required at millimeter wave for a reference range of 1 km is not available by any commercial or laboratory solid state devices. However, the availability of PmP with multigigabit data rate is pivotal for the new high density small cell networks for 4G and 5G and to solve the digital divide in areas where fiber is not convenient or possible to be deployed. In this paper, the advancements of the novel approach proposed by the EU Horizon 2020 TWEETHER project to create the first and fastest outdoor W-band (92 -95 GHz) PmP wireless network are described. For the first time a new generation W-band traveling wave tube high power amplifier is introduced in the transmission hub to provide the enabling power for a wide area distribution.

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