Abstract-At the time of writing, vehicle-to-vehicle (V2V) communication is enjoying substantial research attention as a benefit of its compelling applications. However, the ever-increasing teletraffic is expected to result in overcrowding of the available band. As a first resort, multiple-input multiple-output (MIMO) can be utilized to enhance the attainable bandwidth efficiency or link reliability. However, in hostile V2V wireless propagation environments the achievable multiple-antenna gain is eroded by the channel correlation. As a promising MIMO technique, spatial modulation (SM) only activates a single transmit antenna (TA) in any symbol-interval and hence completely avoids the inter-antenna interference (IAI), hence showing robustness against channel correlation. As a further powerful solution, non-orthogonal multiple access (NOMA) has been proposed for improving the bandwidth efficiency. Inspired by the robustness of SM against channel correlation and the benefits of NOMA, we intrinsically amalgamate them into NOMA-SM in order to deal with the deleterious effects of wireless V2V environments as well as to support improved bandwidth efficiency. Moreover, the bandwidth efficiency of NOMA-SM is further boosted with the aid of a massive TA configuration. Specifically, a spatiotemporally correlated Rician channel is considered for a V2V scenario. We investigate the bit error ratio (BER) performance of NOMA-SM via Monte Carlo simulations, where the impact of the Rician K-factor, spatial correlation of the antenna array, time-varying effect of the V2V channel, and the power allocation factor is discussed. Furthermore, we also analyse the capacity of NOMA-SM. By analysing the capacity and deriving closedform upper bounds on the capacity, a pair of power allocation optimization schemes are formulated. The optimal solutions are demonstrated to be achievable with the aid of our proposed algorithm. Again, instead of simply invoking a pair of popular techniques, we intrinsically amalgamate SM and NOMA to conceive a new system component exhibiting distinct benefits in the V2V scenarios considered.Index Terms-Spatial modulation (SM), non-orthogonal multiple access (NOMA), massive multiple-input multiple-output (MIMO), vehicle-to-vehicle (V2V), channel capacity, bit error ratio (BER).

Aims/hypothesis Human patients with aniridia caused by heterozygous PAX6 mutations display abnormal glucose metabolism, but the underlying molecular mechanism is largely unknown. Disturbed islet architecture has been proposed as the reason why mice with complete inactivation of paired box 6 (PAX6) in the pancreas develop diabetes. This is not, however, the case in human aniridia patients with heterozygous PAX6 deficiency and no apparent defects in pancreatic development. We investigated the molecular mechanism underlying the development of abnormal glucose metabolism in these patients. Methods A human aniridia pedigree with a PAX6 R240Stop mutation was examined for abnormal glucose metabolism using an OGTT. The underlying mechanism was further investigated using Pax6 R266Stop mutant small-eye mice, which also have abnormal glucose metabolism similar to that in PAX6 R240Stop mutation human aniridia patients. Results Paired box 6 (PAX6) deficiency, both in aniridia patients with a heterozygous PAX6 R240Stop mutation and in mice with a heterozygous Pax6 R266Stop mutation, causes defective proinsulin processing and abnormal glucose metabolism. PAX6 can bind to the promoter and directly upregulate production of prohormone convertase (PC)1/3, an enzyme essential for conversion of proinsulin to insulin. Pax6 mutations lead to PC1/3 deficiency, resulting in defective proinsulin processing and abnormal glucose metabolism. Conclusions/interpretation This study indicates a novel function for PAX6 in the regulation of proinsulin processing and glucose metabolism via modulation of PC1/3 Diabetologia

Apoptosis is a genetically determined cell suicide program. Mitochondria play a central role in this process and various molecules have been shown to regulate apoptosis in this organelle. In the present study, we firstly identified that protein tyrosine phosphatase interacting protein 51 (PTPIP51) is a novel mitochondrial protein, which may induce apoptosis in HEK293T and HeLa cell lines. PTPIP51 transfection resulted in the externalization of phosphatidylserine (PS), activation of caspase-3, cleavage of PARP, and condensation of nuclear DNA. Further investigation revealed that PTPIP51 over-expression caused a decrease in mitochondrial membrane potential and release of cytochrome c, suggesting that it may be involved in a mitochondria/cytochrome c mediated apoptosis pathway. We also found that a putative TM domain near the N terminus of PTPIP51 is required for its targeting to mitochondria, as evidenced by the finding that deletion of the PTPIP51 TM domain prevented the protein's mitochondiral localization. Furthermore, this deletion significantly influenced the ability of PTPIP51 to induce apoptosis. Taken together, the results of the present study suggest that PTPIP51 is a mitochondrial protein with apoptosis-inducing function and that the N-terminal TM domain is required for both the correct targeting of the protein to mitochondria and its apoptotic functions.

The programmed cell death 5 (PDCD5) protein plays an important apoptosis-accelerating role in cells undergoing apoptosis. Decreased expression of PDCD5 has been detected in various human carcinomas. Here we describe that one potent short interfering RNA (siRNA) against the PDCD5 (siPDCD5) specifically inhibits the expression of PDCD5 at both the mRNA and protein level. Cells with decreased PDCD5 expression displayed reduced sensitivity to an apoptotic stimulus induced by Bax overexpression in HeLa, HEK293 and 293T cell lines. Furthermore, we also show that siPDCD5 inhibited both caspase-3 activity and procaspase-3 cleavage. Suppressed expression of PDCD5 attenuates the release of cytochrome c from mitochondria to cytosol induced by Bax overexpression. This phenomenon is accompanied by the reduced translocation of Bax from the cytosol to mitochondria. MTT assay shows that targeted suppression of PDCD5 expression markedly promoted cell proliferation in Hela and HEK293 cell lines. Our data suggests that PDCD5 may exert its effects through pathway of mitochondria by modulating Bax translocation, cytochrome c release and caspase 3 activation directly or indirectly, and that decreased PDCD5 expression may be one of the mechanisms by which tumor cells achieve resistance to apoptotic stimulus induced by anticancer drugs.

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