It is important to differentiate between reinfection and recrudescence (i.e., reactivation of lingering virus infection from sanctuary sites). However, this distinction is not straightforward. For example, Gousseff and colleagues reported on a case series of 11 patients with probable reinfection or recrudescence [65]. These individuals were re-positive for SARS-CoV-2 by qRT-PCR, and infectious virus was found in culture swabs from one of only two individuals tested. Reinfection was the likely scenario in a subgroup of younger, healthy HCWs (median age 32 years) that experienced a relatively mild clinical relapse. A durable immune response may have not elicited in these patients because of mild infection. On the contrary, a subset of older patients (median age 73 years) without occupational exposure required hospitalization for both episodes, leading to death in almost half of them. This suggested recurrence, potentially due to suboptimal control of infection, thus allowing a second episode of viral replication.
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(a) Portable supine CXR shows intubated patient with mixed ground glass opacification and consolidation in the peripheries of the middle and lower zones. There is relative sparing of the central and upper zones. There is no associated pleural effusion. (b) Axial high resolution reconstructed CECT image across the middle zone of the lungs shows extensive bilateral lung disease with relative sparing of the anterior lobar segments. Consolidation is most notable in the superior segments of the lower lobes with smaller foci in the posterior segment of the right upper lobe. There are ground glass opacities in the lateral regions, distinct from the non-diseased medial portions of the right upper and left lingular lobe.
In order to adapt with the persistent Pi-limiting conditions, plants have evolved a variety of adaptive strategies, collectively known as Pi starvation responses (PSR) [3]. The implementation of these strategies requires sophisticated sensing and regulatory mechanisms that can integrate external and internal Pi status [4]. PSRs generally comprised of local and systemic responses. Local responses involve external Pi sensing and are regulated by local Pi status in monitoring root system architecture to enhance Pi acquisition whereas systemic or long distant responses are dependent on internal Pi concentration and include enhancement of Pi uptake, translocation and recycling of cytoplasmic Pi to maintain metabolic balance of P at the whole-plant level [3, 5]. A major part of the systemic responses in plant under Pi deprivation is regulated by PHOSPHATE STARVATION RESPONSE 1 (PHR1) and related transcription factors [6]. PHR1 mediated downstream Pi starvation-induced genes including PHT1, PHF1, SPX, PAP genes through binding to a P1BS cis-regulatory motif (GNATATNC) present in their promoters [7,8,9,10,11]. Apart from PHR1, other transcription factors have also been reported to be involved in transcriptional regulation of PSR such as WRKY45, WRKY75, WRKY42, OsMYB4P, OsMYB5P, ZAT6 and bHLH32 [12,13,14,15,16,17,18]. Most of these factors were identified in model plants, such as Arabidopsis and rice. In oil palm, however, only the high affinity phosphate transporter (EgPHT1) has been reported. Functional characterization of its promoter in homologous and heterologous model systems demonstrated that its activity is induced specifically in the roots under Pi starvation [19].
A total of 22 putative TFs within 13 families were annotated from the DEG list using the plant TF database PlantTFDB version 4.0 ( ) (Table 4). Among these, the proteins belonging to the MYB and G2-like family made up the two most abundant DEGs. In plants, most of the identified MYB family proteins are associated with Pi starvation regulatory mechanism [30]. All three TFs belonging to the MYB family exhibited attenuated expression patterns at 14d. Meanwhile half of the MYB proteins were up-regulated at 28d. Three TFs belonging to the G2-like family were detected from the DEG list. Remarkably, two G2-like TFs containing MYB-CC domain (105,050,046 and 105,058,550) were inversely regulated at 28d (one up-regulated and the other down-regulated). Besides, both bHLH family TFs (105,048,562 and 105,051,179) were found to be suppressed at 28d in which the latter encoding for a FER-LIKE IRON DEFICIENCY_INDUCED (FIT) TF. FIT TF is recognized as the key player in Fe homeostasis by regulating the expression of iron deficiency responsive genes [31]. Plant hormones assist in plant responses to nutrient limitation by mediating nutrient signalling and plant growth and development [32]. In this study, three genes encoding TFs potentially involved in hormone signal transduction were found to be responsive to Pi deprivation stress. Two ethylene signalling-related genes (105,059,334 and 105,046,219) were up-regulated at 28d and categorized into different TF families, AP2/ERF and EIL respectively. In addition, expression of a putative scarecrow-like protein (105032345), a member of GRAS family, was highly induced in roots under low Pi stress. GRAS gene family members are involved in diverse elemental processes of plant growth and development, ranging from gibberellin acid signalling, radial root patterning and phytochrome signalling [33].
A highly conserved PHR1-mediated signalling cascade has been well-documented in Arabidopsis and rice [7, 54]. Although AtPHR1 in Arabidopsis and its functional equivalent, OsPHR2 in rice have been demonstrated as the central player in coordinating various transcriptional regulations in response to Pi starvation, the expression of both transcripts were irrespective to Pi fluctuation [55, 56]. Nonetheless, the expression profiles for both PHR1 and PHR2 in oil palm were relatively stable throughout the 28d of Pi deprivation treatment as revealed in the qRT-PCR analysis. In Arabidopsis, PHR1 was shown to act redundantly with other members in the MYB-CC family, PHL1, PHL2, PHL3 and PHL4 in modulating plant transcriptional responses to Pi scarcity. Besides, the expression levels of AtPHL2 and AtPHL3 were also shown to be positively triggered by Pi starvation while the others were not affected by external Pi levels [7, 57, 58]. Meanwhile, two genes encoding PHL7 and PHL8 TFs were differentially regulated in oil palm seedling roots at 28d. By possessing a common MYB domain and a coiled-coil domain, both proteins might also play a key role in controlling oil palm transcriptional responses to Pi deficiency similar to their orthologue in Arabidopsis. Moreover, PHL7 was significantly induced starting from 21d to 28d in Pi-starved oil palm root tissues as revealed in the qPCR analysis. The distinctive transcription pattern of these two TFs under low Pi stress suggested that they may be regulated by different molecular components.
Induction and secretion of intracellular and/or extracellular APases are considered to be an important acclimation strategy for plant tolerance under low Pi environment which has been documented in diverse crop plants [68, 69]. PAPs represented the largest class of plant APases that could be secreted into the rhizosphere to hydrolyse organic P compounds whereas the intracellular PAPs could facilitate the Pi remobilization from internal reservoir. With the presence of P1BS motifs in their promoters, PAP genes are positively controlled by the PHR1-mediated Pi starvation signalling pathway [70, 71]. Accretion of APases transcripts was commonly reported in several recent transcriptomic studies involving Pi-starved soybean, maize and banana [41, 72, 73]. Therefore, it is expected that three APases genes were positively stimulated at 28d. Transgenic plants overexpressing PAP gene depicted increased APase activities, leading to the enhanced use of external organic P sources, higher plant biomass and eventually improved plant growth under Pi limitation [11, 74]. Hence, these differentially regulated PAP genes deserve further studies with regards to their roles in Pi scavenging and recycling.
The traditional meetings, incentives, conferences, and exhibitions (MICE) industry has been hit hard by social distancing regulations introduced to combat the COVID-19 pandemic, with concerns about pandemic risks and personal hygiene increasing the demand for online MICE technology. With the introduction of innovative new technologies to the MICE industry, it is important to study the psychology of online MICE attendees, particularly the factors affecting their behavioral intention to adopt online MICE technology during the pandemic. This study investigates the attitudes toward attending online MICE since the start of the epidemic based on the health belief model (HBM) and innovation diffusion theory (IDT). A total of 439 valid questionnaires were collected in China and used for structural equation modeling. The results show that the perceived safety threat, the comparative advantage, trialability, and outcome expectations positively impact the attendees' attitudes. Moreover, this study finds that attitude completely mediates the impact of perceived safety threat, comparative advantages, trialability, and outcome expectation on behavioral intention to attend online MICE events. These findings theoretically enrich the understanding of online MICE technology, the HBM, and the IDT and offer managerial implications for MICE organizers and exhibitors.
Defamation is criminalized in the penal code, but to date, no charges have been brought under this law to punish online speech.5 Civil defamation law is fearsome enough. PAP leaders have been awarded damages in the range of SGD 100,000 to 300,000 each (US$71,000 to US$213,000) in defamation suits brought against opposition politicians and foreign media corporations.6 Electronic media have been affected: In 2002, a libel suit was leveled at Bloomberg for an online column; it settled out of court and paid three leaders damages totaling SGD 595,000 (US$422,000). The offense of scandalizing the judiciary is another law that has been used to punish criticism of the court that in most democracies would be considered to fall within the norms of political debate. In 2008, a blogger was sentenced to three months in prison for this offense.7
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