Centralized waiting lists (CWLs) for patient attachment to a primary care provider have been implemented across Canada, including Quebec. Little is known about the implementation of CWLs and the factors that influence implementation outcomes of such primary care innovations. The purpose of this paper is to explain variations in the outcomes of implementation by analyzing the characteristics of CWLs and contextual factors that influence their implementation.A multiple qualitative case study was conducted. Four contrasting CWLs were purposefully selected: two relatively high-performing and two relatively low-performing cases with regard to process indicators. Data collected between 2015 and 2016 drew on three sources: 26 semi-structured interviews with key stakeholders, 22 documents and field notes. The Consolidated Framework for Implementation Research was used to identify, through a cross-case comparison of ratings, constructs that distinguish high from low-performing cases.Five constructs distinguished high from low-performing cases: three related to the inner setting: network and communications; leadership engagement; available resources; one from innovation characteristics: adaptability with regard to registration, evaluation of priority and attachment to a family physician; and, one associated with process domain: engaging. Other constructs exerted influence on implementation , but did not distinguish high and low-performing cases.This is the first in-depth analysis of CWL implementation. Results suggest important factors that might be useful in efforts to continuously improve implementation performance of CWLs and similar innovations. Implementation of innovations is a key step in the diffusion–dissemination–implementation process in terms of maximizing the likelihood of achieving beneficial outcomes . HoweverDespite increasing recognition that context must be considered when looking at variations in the effectiveness of implementation, this research domain is still evolving. Some authors . Indeed,Innovations are introduced regularly in all countries to address problems that appear in healthcare systems. In Canada, the high number of patients without a regular primary healthcare provider has gained increasing attention in reform efforts . Canada’This study aims to explain and understand variations in the outcomes of implementation by analyzing the characteristics of CWLs and contextual factors that influence their implementation.In Canada, seven provinces have implemented CWLs to better manage supply and demand for attachment to a primary healthcare provider . AlthougThis study analyzes CWLs implemented in the province of Quebec, considered a pioneer in CWLs for unattached patients . This prThe CWLs in Quebec, called “Guichets d’accès aux clientèles orphelines” (GACOs) were implemented in 2008 by the Ministry of Health and Social Services (MSSS) in collaboration with the Quebec Federation of General Practitioners. They have a dual objective of: attaching patients to a family physician, and prioritizing vulnerable patients . GACOs wThe GACO in each HSSC is managed by a clerk who receives requests; a nurse who evaluates patient requests on a priority scale based on their clinical profile in collaboration with a local medical coordinator; a physician mandated to help attach patients with a family physician . People Almost a decade after launching the GACO model of CWLs, a research team in Quebec published a performance assessment focused on four outcomes of the implementation process: new requests for a family physician, change in the number of patients on the waiting list and numbers of patients and vulnerable patients attached to a family physician through the CWLs . The assThe Consolidated Framework for Implementation Research (CFIR) developed by the outer setting is defined by the larger socio-demographic, economic, political, geographic context surrounding the inner setting within which the GACO is implemented ;the inner setting refers to characteristics  of the organization where the GACO is implemented: the LHN. It includes both the HSSC in which the GACO is physically located, and all the primary care structures included in the LHN related to that HSSC refer to ;the characteristics of individuals involved in the implementation, including GACO staff members and the family physicians of the LHN, consider knowledge and beliefs, self-efficacy, stage of change and identification with the organization;the innovation characteristics describe characteristics of the GACO related to its adaptability to a given setting, complexity, trialability, evidential support and its relative advantages (or disadvantages); andthe process of implementation refers to planning, engaging, executing, reflecting and evaluating the GACO process as interrelated sub-processes known to have a key role in implementation.Taking a whole system approach, the five domains were operationalized and adapted in the present study as follows:A formative evaluation using qualitative multiple case study design was chosen to gain an in-depth understanding of phenomena in “real world settings [where] the researcher does not attempt to manipulate the phenomenon of interest” .Our study builds on results of the recent performance assessment of Quebec’s CWLs for unattached patients, which emphasized the need to better understand variations arising both from within the GACOs and from external local or regional influences . Cases wTo compare performance across the province, indicators for each GACO were transformed into rates per 10,000 population, and were classified into tertiles of relative performance: low, average or high. Contrasting cases were selected (lower vs higher performing GACOs) to understand and explain contextual conditions that led to different process outcomes  and suppData collection took place between May 2015 and June 2016 and drew on three main sources in order to triangulate data: semi-structured interviews with a range of GACOs stakeholders, documentation from the GACOs and field notes taken during and after interviews .For every case, we conducted semi-structured interviews with between five and eight stakeholders with different perspectives. All staff involved in the GACO implementation  and a few family physicians, with experience in attaching patients from the CWLs, were asked to take part in the study. A total of 26 key stakeholders were interviewed, using an interview guide based on the main domains of the CFIR. Interviews lasted between 45 and 90 min. It should be noted that in one case (Case 2), the local medical coordinator position was vacant at the time of data collection and the nurse declined our invitation to participate in the study.Field notes were taken during and after each interview by the interviewers to summarize the main elements discussed with participants, to capture factors emphasized by participants, to describe observations made by interviewers, to reflect on potential explanatory factors and to note modifications to make to the interview guide or clarifications to seek in upcoming interviews. In total, 22 documents  about the GACO structure and process were collected and reviewed to understand each component of the GACOs, and key stakeholder roles at strategic and operational levels.All three forms of data  were analyzed. Interviews were transcribed and coded using NVivo software. Documents and field notes were coded manually. Analysis followed a three-stage process. First, we applied a deductive approach using a codebook based on the CFIR to guide data coding and analysis. The codification was controlled by the technic of double coding: a research assistant and a researcher, both blinded to the implementation performance status of the four GACOs, coded all interviews independently, meeting periodically to compare and revise codes. When disagreements were observed, the codebook was adjusted and codes inspired from the CFIR were redefined to better fit the context of GACO implementation. Finally, persistent discrepancies were resolved through discussion with the larger research team. A narrative summary, based on the CFIR constructs, was created for each interview within each case to provide a rich description of each GACO’s story. A case-specific matrix with illustrative quotes for each GACO summarized information related to how each CFIR construct influenced implementation. This process led to four narrative summaries and four case-specific matrices organized according to the CFIR constructs.Second, the first author applied ratings, based on the summaries and matrices, to the coded constructs at the GACO level, using the rating rules described by Application of the ratings was checked by two co-authors  for a random subset of constructs within each case; and a double rating was done by (M-AS) for another random subset of coded constructs.In the third stage of analysis, we compared ratings for each construct across all four GACOs using a cross-case analytic matrix that was developed to identify patterns of variation by construct across cases. Finally, a detailed matrix of the specific CFIR constructs with a special focus on categories that distinguished between high and low implementation performance allowed us to draw conclusions on patterns of variation in factors that influenced GACO implementation outcomes. As per In our study, we examined the difference in positive or negative ratings between high and low-performing cases to determine if the construct was an important distinguishing factor and also relied on the supporting qualitative summary. If a difference was of at least two points, the construct was considered to make a strong distinction.To ensure scientific rigor, double blinded coding was performed on all transcripts and double rating and checks were also conducted on a random subset of constructs within each case. Also, an audit trail was kept of all changes made to the codebook as coding and analysis progressed throughout the study . PrelimiIn this section, we discuss the five main constructs that helped identify relevant and rich explanations of variation between high and lower performance level cases. These constructs were: network and communications; leadership engagement; available resources; adaptability; and engaging.Outer setting constructs ; inner setting constructs ; innovation characteristics , and individual characteristics  exerted influence on GACO’s implementation, but did not distinguish cases by level of performance.Two levels were considered: within services of the HSSC where the GACO is implemented and between the services of the LHN.So when patients call me back, they might tell me between noon and two o’clock. We’ve created codes so that I write that the patient called back, and can be reached between noon and two, and I put a code, for example PM. In prioritizing, the nurse will see that it’s between noon and two, with the PM code to call that person.(Case 4 Clerk)There was evidence in all cases of good communication and network relationships sustained through informal and regular formal meetings of GACO staff (e.g. clerk and nurse). However, among GACO staff, collaborative practice to address common work issues and rapidly match a patient to a family physician appeared more developed in Cases 3 and 4 (rated high). In Cases 1 and 2 (rated low), staff were still trying to improve work procedures. Moreover, differences were seen between high and low performers in the extent of communication among GACO staff around the goal of minimizing delays to prioritize patients. In Cases 3 and 4 (rated high), staff had developed innovative communication strategies to solve problems arising from the complexity of the GACO process. While all sites were aware of this problem, only GACOs 3 and 4 had smoothed workflow procedures by instituting a communication system involving formal or informal procedures. In Case 4, staff recorded their initial comments and nurses and clerks developed symbol systems and codes that helped the nurse identify priority patients quickly, ensured work continuity, and enhanced patient access to a family physician:The most innovative practice was a formal communication strategy developed in Case 3 (rated high) using an online computer-based system to perform a quick pre-prioritization of patients with special needs and reduce delays for urgent patients (e.g. vulnerable patients) to avoid compromising their health status.We’re really waiting for the computer program that will help us prioritize them, which will help. We’d certainly like to do more to prioritize them, but we still have to take the time to assess them.(Case 1 Manager)It is noteworthy that in Case 1 (rated low), despite attempts by the clerk to help the nurse prioritize participants, both manager and clerk admitted that problems persist, and said they were eager to put in place a computer communication system to facilitate pre-prioritization of patients:In Cases 3 and 4 (rated high), participants described good working relationships between GACO staff and health professionals working in collaborating clinics. In Case 3, for instance, good communication between the GACO clerk and some of the local clinics facilitated patient care in case of emergency. In Cases 3 and 4, transmission of medical information and health assessments to family physicians via the medical record of patients referred from the GACO was seen to speed follow up and increase family physician willingness to participate in the GACO.Some participants  in Case 4 (rated high) mentioned that communication and collaboration between GACO staff and physician clinics was sometimes difficult (e.g. GACO staff have to follow up with clinics to know if a patient has been refused by the physician). Nevertheless, GACO staff made efforts to organize discussion with clinics to overcome breaks in communication and minimize their negative impact on patients.Here, we have many clinics, 30 or so clinics that work in silos and don’t speak to each other. There’s no real spirit of belonging to a HSSC. Now it’s starting to improve between certain clinics, but there are some who don’t participate in anything. There are some we never see. These people will almost never take on patients from the GACO.In contrast, in Case 1 (rated low), most physician clinics on the territory operated in isolation, which hampered their participation in the GACO. Poor communication between clinics limited collaborative practice and hindered family physician participation in GACO:Regarding patients, no, (physicians have not received information from the GACO). The […] information we received, and it’s been a while, it’s our physician lead (of the clinic) who went to get it.(Case 2 Family Physician 1)In Case 2 (rated low), some participants reported that the GACO nurse facilitated referral of certain cases through personal contact with family physicians, and helped with patient transfers following retirement of a family physician. However, local family physicians in clinics had different perceptions and complained of poor communication from the GACO about patients on the waiting list and changes in GACO procedures. They even mentioned that the medical director of the clinic had to seek out this information himself:In Case 2 (rated low) and Cases 3 and 4 (rated high), participants emphasized the leadership of formally appointed leaders  or emergent leaders (Case 4) to achieve GACO goals.In Cases 2 and 3, medical coordinators played a role in solving problems, encouraging family physicians to attach patients, managing patient requests and attaching many vulnerable patients. In Case 4, the medical coordinator’s lack of engagement was compensated by the leadership executed by two professionals who emerged as champions and played an active role in implementation efforts: the GACO nurse, who was enthusiastic, proactive and keen on reducing long waiting times for patients, and created adaptive strategies to leverage resources; and a young family physician who was highly engaged and attached a large number of babies and vulnerable patients (400) from the GACO during his first year of practice.I went to see several clinics because I knew a few physicians who had worked here in the past. But with doctors, it takes a doctor to talk to them. I may have the best intentions, make action plans, say “I’ll go see this or that clinic.” Little things get done, but the bulk of it has to go through physicians.Despite, similarities across Cases  regarding leadership, some key differences between low and high-performing cases were highlighted. Participants in Case 2 mentioned the difficulty of mobilizing family physicians to attach patients during a period when the medical coordinator was absent and there was a void in leadership. The manager who temporarily filled his role admitted having limited capacity to recruit family physicians and emphasized that implementation had to be physician driven to incite family physicians to attach patients from the GACO:Also, despite the Case 2 (rated low) medical coordinator’s support for staff in resolving problems encountered with family physicians, he did not, despite intending to do so, implement a strategy to offer patients alternative health services; a more proactive approach was evident in Cases 3 and 4 (rated high). Moreover, staff expressed their concerns about lack of continuity in the medical coordinator role and difficulties sustaining improvements to the GACO after the coordinator’s departure.He  tried to do a little public relations with the clinics. […] He doesn’t have a very aggressive management style and, as well, these are his colleagues. We can’t forget that this is a doctor talking to other doctors. It’s a delicate balance. He can’t impose on them: he’s a doctor himself. He practices in a clinic, he has his clientele, he knows what he’s talking about because he lives it every day; he can’t impose upon them […]. I don’t know what his relation is, but he’s a very nice man, not aggressive, very forthcoming, but […] that’s that.(Case 1 Nurse)In Case 1 (rated low), no specific champion was mentioned. Participants noted that the medical coordinator fulfills a traditional role, providing support when needed and dealing with problematic family physicians. Compared to other GACOs, he was insufficiently committed to enhance family physician participation. The tie with family physicians working in clinics was weak:The nurse’s statement was endorsed by the medical coordinator himself, who admitted “not twisting the arms of family physicians” to attach patients from the GACO. “No, I didn’t twist their arms like that” . He was not known by one of the family physician interviewed practising in one clinic. “The medical coordinator at the GACO? No I don’t know who that is” (Case 1 Family Physician 2).That’s it? They start cutting: the nurse who was supposed to be there five days a week is now on three days. Then she leaves on retirement, and there’s a chance she won’t be replaced. I may end up on my own and then I’ll really lose my mind.(Case 1 Clerk)Lack of adequate staffing, inadequate technology, high staff turnover and financial constraints were highlighted in all cases as barriers to implementing the GACOs. Inadequate human resources caused problems in both processing patients’ registration on the GACO, and in attaching them to a family physician. For example, a lack of family physician capacity on the territory had a negative impact on GACO ability to handle requests for registration. Lack of stability in the clerk’s role led to delays as new clerks had to be trained. As well, the lack of additional funds allocated for implementation efforts constrained recruitment of additional human resources. No additional staff was made available for GACO implementation efforts and no extra support was provided to the HSSC within which the GACO operated. The HSSC had to make do with existing staff, who were assigned additional tasks to implement the GACO:The process works well and the fact that we’ve – I’ve talked to others about it when I find myself with other managers – trained a good number of nurses, here and there; we’re open on weekends, and sometimes people don’t show up for their Saturday or Sunday appointments. It’s a good time to catch people at home. The weekend nurses, everyone knows, turn on the computer and sign into the SIGACO (database). All that contributes to reducing the need to bring in pregnant nurses and all that. When I mention this elsewhere, nobody’s doing it […] “That’s a great idea,” they say. Because no one has a budget for this. We have a 0.8 clerk and I believe the salary of one nurse, and in some places that can be a very part-time nurse, so […] in that way, we manage to make the machine roll along smoothly.(Case 4 Nurse)Along with human resource challenges, GACOs had difficulties accessing the medical insurance database to verify patients’ attachment status . All cases faced these challenges, but Cases 3 and 4 (rated high) found creative ways to deal with them. Case 4 developed an adaptive strategy to optimize GACO resources by making full use of the local HSSC nursing staff. For example, a full-time clerk and several nurses who were not initially assigned to patient prioritization worked on GACO efforts whenever their schedule allowed. Training many nurses to conduct patient evaluations expanded the potential resource pool and reduced reliance on a single person:I would say that she [the nurse in the other department] has a lot on her plate. She helps us depending on the number of patients she has. There are evenings when she can’t do anything for the GACO, and evenings when she can help us out […] She does some prioritization, telephone evaluations for prioritization. It depends. Sometimes we ask her to do the RAMQ [Régie d’Assurance Maladie du Quebec-Quebec Health Insurance Board] checks. Sometimes, in researching on the RAMQ site, you find that they (the patients) have found a family physician by themselves. So there’s an elimination in that time.(Case 3 Nurse)Along the same lines, Case 3 (rate high) managed to overcome human resource constraints through their innovative pre-prioritization system. They recruited a nurse clinician working in another department who agreed to help GACO staff prioritize patients, and check their status in the medical insurance database:In all four cases, the GACO was adapted to meet community needs. Adaptations were related to one of three GACO activities: registration, evaluation of priority and attachment.If they don’t come to the GACO, the GACO will come to them […]. So I tell them “I’m the system that comes to see you.” I’m the HSSC nurse who goes out to present them the services offered by the CLSC, and register them for the GACO as well. So then, personally giving them the leaflet. “So now you’ll get your life on track, call us back. Your wait to get a family doctor has already begun” […] I prioritize them on the spot. You check if they have their RAMQ [Quebec Health Insurance Board] number […] I look, because I have access, to see if they have a doctor. With some, I’ve even called RAMQ with them because even I get lost in the system when I call there, so you can imagine what it’s like for this poor man.(Case 4 Nurse)In response to an overwhelming volume of calls, all four cases decided to replace telephone registration by an online registration form. What differentiated high-rated and low-rated GACOs were the procedures designed to support registration of specific population groups such as newborns and homeless patients. Cases 3 and 4 (rated high) implemented procedures to facilitate registration, which was not done in low-performance cases. In Case 3, GACO staff developed an internal procedure to register newborns on the waiting list even though the provincial GACO software did not permit registration until the baby had received a health insurance number. Case 4 used an outreach strategy whereby the GACO nurse visited homeless shelters monthly to help patients sort out their eligibility for the GACO and register:A major difference between the two groups of GACOs was that Cases 3 and 4 (rated high) put in place creative initiatives to offer alternative health services while patients waited on the GACO. This was not done in lower-rated Cases 1 and 2. For instance, Case 3 offered the possibility of receiving transitional care while waiting for a regular physician from an ambulatory unit for patients with high needs. Case 4 developed a center for disease prevention for patients in good health, which helped to evaluate non-urgent patients and offer them a check-up by a nurse, based on the guidelines, while they were on the waiting list. If a change in their health status or needs was noted, the process of being attached to a family physician could be accelerated.In general, we try to provide a mix of cases. If he just wants diabetic patients, we’ll try to maybe send him four out of five, with the fifth being a patient with diabetes and mental health issues. We put some effort into accommodating them, but also have a clear view of our reality, which is far from easy.(Case 4 Clerk)Cases 3 and 4 (rated high) developed strategies to deal with family physician preferences, whereas Cases 1 and 2 (rated low) complied fully with physician demands. Case 3 implemented a restrictive approach, and did not allow physician preferences to influence patient referrals. Case 4 implemented a more flexible strategy, with GACO staff adjusting referrals to physician preferences while also taking into consideration the patient’s health profile and the importance of their needs. In Case 3, GACO staff urged family physicians to attach patients referred to them, keeping an inventory of the characteristics of each family physician’s practice to minimize the chance they would refuse a patient; GACO staff would also reduce the number of referrals as needed to a given family physician to ensure that patients would be seen by them within appropriate timelines. In Case 4, despite trying to accommodate family physicians, participants decided to refer patients with mental health problems even when family physicians did not want to take them:In Cases 3 and 4 (rated high), adaptation according to distance and region was a noteworthy theme, whereas this was not done in Cases 1 and 2 (rated low). Case 3 used postal codes to refer patients to the closest GACO; in Case 4, this was not always possible due to limited family physician capacity on the territory covered by the GACO, which did not allow patients to choose a region for attachment.My own family doctor didn’t know about the GACO, and she’s on the territory. Not all small clinics attend the regional department of family physicians meetings, which keeps them up to date, so there is a need for, like in [one region], they do a lot of PR [public relations], they even have a little pamphlet, I kept it, I found it cute that the coordinator himself went around to the clinics and handed them out. Definitely, new doctors who arrive, if they’re looking […].(Case 1 Clerk)The promotion of the GACO to patients and family physicians in Cases 1 and 2 (rated low) was slower and less developed than in the high-rated cases. Participants from lower performing Cases 1 and 2 acknowledged that promoting the GACO, attracting family physicians to attach patients from the GACO and encouraging patients to use GACO services, were major concerns. In interviews, participants stressed the enormous efforts required to publicize the GACO. For example, in Case 1 (rated low), they suggested promoting the GACO by distributing pamphlets to patients in clinics. In Case 2, the manager admitted that there is still a lot of work to be done with family physicians to inform them about the GACO in order to obtain results:We promoted on-line registration at that point. We made little bookmarks that we distributed to the clinics on our territory.(Case 3 Manager)Compared to the other sites, Case 3 (rated high) was keen on marketing and driving use of the GACO, providing clinics with updates on adjustments made during implementation (e.g. distributing bookmarks when launching the online registration) to increase GACO use by family physicians and patients:We left them in pharmacies and clinics. Little pads like this. They were all over the area.(Case 4 Clerk)Case 4 (rated high) limited promotion of the GACO at first, because they were afraid of having too many patient requests, but later distributed flyers in French and English through clinics, pharmacies, and community organizations :Our study succeeded in identifying factors that enhance implementation effectiveness and may be used to address performance shortcomings in CWLs. Five main influencing factors were seen to operate at different levels, interact synergistically and work together in mutually reinforcing ways to produce implementation process outcomes. These factors were also seen in four other similar studies  put in place to overcome implementation challenges. Similar strategies have been adopted when implementing advanced access, an innovation to improve timely access to primary care (With regard to the innovation (GACO) characteristics, our results indicate that high-performing GACOs were more innovative in embracing complexity than low-performing GACOs, and adapted the innovation to their local settings and the needs of patients on the waiting list. GACOs required continuous adaptation by staff. Indeed, adaptation is likely to occur when complex innovations unfold in real-world context  directives and the tacit knowledge of local stakeholders , who contribute empirically grounded knowledge of the local context and their own lived experience  and management at provincial level; and prioritization according to five new categories reflecting urgency and health needs . The chaDespite the numerous studies examining models that similarly aim to improve timely access to healthcare in different countries , very few have identified and explained factors that differentiate high from lower-performing sites in the implementation of such innovations. Studies that have attempted to address this relationship , and interviews with family physicians, who are knowledgeable informants directly involved in GACOs implementation and/or impacted by the GACOs. Second, the researchers who coded and analyzed data were blinded to the status of implementation in the four GACOs, which helped reduce bias in qualitative findings and ensure trustworthiness. Double coding was performed using an iterative process, which also helped to increase credibility. Analyzing the results through the CFIR helped synthetize results, will facilitate future comparison of findings across other similar studies adopting the same methodology.A few limitations to the current study should be mentioned. First, the number of participants at Site 2 was less than the number of the other three sites and may have yielded a less rich picture. Additional results may have been captured if the GACO nurse had agreed to be interviewed.Second, we selected four sites among 94, given our objective was not to produce statistically generalizable results, but rather a rich contextualized understanding of each GACO. The final limitation of this study relates to the absence of patients’ experience with the GACO. Future research should include interviews with patients who were attached with a family physician through these CWLs, and with those who remain on the waiting list.We also point out that we have presented in detail only 5 among a possible 39 distinguishing constructs. We do not consider this problematic given that use of a limited number of constructs has been recommended by the designers of the framework  and otheThis study provides the first in-depth analysis of CWLs implementation. Findings can be used to develop strategies to overcome barriers to implementation, better manage wait lists, and improve performance. Ultimately, they could contribute to reducing inequities in access to a family physician, and in health outcomes, notably for vulnerable populations and those with complex physical and/or mental healthcare needs. Findings are also relevant for decision makers responsible for designing complex innovations whose decisions shape the development, implementation and scale-up of CWLs. They may also more generally inform the dissemination efforts of similar complex organizational models in different contexts. When implementing this innovation in similar real-world healthcare delivery contexts, and when redesigning implementation strategies, greater consideration should be given to the combination of organization-level factors , intervention characteristics (adaptability) and the process domain (engagement) identified as factors important to achieving implementation outcomes. Moreover, a mandated innovation that is simultaneously top-down and less prescriptive creates a good opportunity for stakeholders in the field to identify practical ways to bring about change.


The isolated SCs were then treated in vitro with a control ) or a high substrate growth media (HSM) . Cells were assessed on their ability to proliferate, differentiate, and fuel substrate oxidation after differentiation. The effect of HSM was measured as the percentage difference between SCs exposed to HSM compared to control media. In vitro SC function was not affected by donor age. OVF reduced SC proliferation rates (–19% p < 0.05) but did not influence differentiation. Cellular proliferation in response to HSM was correlated to the donor’s body mass index (BMI) . When exposed to HSM, SCs from normal weight (BMI 18–25 kg/m2) participants exhibited reduced proliferation and fusion rates with increased fatty-acid oxidation (p < 0.05), while SCs from participants with higher BMIs (BMI 25–32 kg/m2) demonstrated enhanced proliferation in HSM. HSM reduced proliferation and fusion (p < 0.05) in SCs isolated from subjects before OVF, whereas HSM exposure accelerated proliferation and fusion in SCs collected following OVF. These results indicated that diet has a greater influence on SC function than age and BMI. Though age and BMI do not influence in vitro SC function when grown in controlled conditions, both factors influenced the response of SCs to substrate challenges, indicating age and BMI may mediate responses to diet. Satellite cells (SC) aid skeletal muscle growth and regeneration. SC-mediated skeletal muscle repair can both be influenced by and exacerbate several diseases linked to a fatty diet, obesity, and aging. The purpose of this study was to evaluate the effects of different lifestyle factors on SC function, including body mass index (BMI), age, and high-fat overfeeding. For this study, SCs were isolated from the vastus lateralis of sedentary young (18–30 years) and sedentary older (60–80 years) men with varying BMIs (18–32 kg/m Muscle mass correlates with increased metabolic rate and lower rates of obesity, as well an improved overall quality of life ,2,3,4. ITo explain the loss in muscle mass associated with age and disease, many researchers have assessed the mechanisms of tissue repair, specifically those mediated by the satellite cell (SC) ,12,13. SSCs commonly exist as quiescent cells located between the sarcolemma and basement membrane of skeletal muscle  and can SC function can be altered by disease and negative lifestyle factors, such as a sedentary lifestyle  and obesDiet-induced obesity (DIO) in rodents is associated with altered SC function, specifically, blunted activation and proliferation and diminished insulin receptor signaling ,32,33. SThis study sought to determine the influence of donor diet, age, and body mass index (BMI) on SC function as defined by their ability to proliferate, and fuse into multinucleated fibers. SCs were collected from: young sedentary lean, young sedentary overweight/obese, aged sedentary lean, and high-fat/hypercaloric fed young sedentary lean donors. 2, and body fat was between 11–33%. All participants were male and sedentary . Participants were grouped as sedentary normal weight , sedentary overweight or obese , or sedentary aged . The SedOld group had an average appendicular skeletal muscle index  of 9.70 ± 0.13 kg/m2  [Human research participants: Skeletal muscle biopsies were obtained under Virginia Polytechnic and State University, Internal Review Board-approved protocols , indica al. [2) ,40.n = 4) from skeletal muscle biopsies collected following the lead-in diet (before OVF) and following OVF diet and used for the studies described herein.Dietary intervention: Using a controlled feeding approach, participants were provided with a 10–14 day lead-in diet immediately followed by a high-fat hypercaloric diet (OVF) for four weeks as described by Osterberg et al. . The leaTM, Lonza, Rockland, ME, USA) for 5 days until they reached 60–80% confluency. After proliferation, cells were differentiated for seven days in a low-serum media (DMEM with 5 mM glucose and 2% horse serum) with differentiation media replaced every 2 days. Amphotericin-B (0.5 ug/mL), antimitotic (for penicillin 100 U/mL and streptomycin 100 ug/mL), and gentamycin (0.01 mg/mL) were added for protection against bacterial and fungal contamination.SCs were collected from tissue biopsies of the vastus lateralis muscle of participants as described in Muoio et al. . SCs werHigh substrate media (HSM) was applied during the proliferation stage of SCs. HSM contained the same ingredients as the control growth media with additional supplementation of 400 mM, 2:1, oleate–palmitate complexed with 5% BSA , and the glucose concentration increased from 5 mM to 25 mM  . GLUT1, ® NF Cell Proliferation Assay Kit . Doubling times were calculated using the PRISM exponential growth equation software [Cells were counted with a hemocytometer and each cell line was seeded in triplicate at 2500 cell/well in 96-well plates. Cells used for proliferation measures were generated after their third passage (P3). Plates were collected on days 1 through 6, and nuclear material was counted using the CyQUANTsoftware   and DNase I treatment , according to the manufacturer’s instructions. qRT-PCR was performed using a ViiA 7 Real-Time PCR System  and TaqMan Universal PCR Master Mix, used according to the manufacturer’s specifications . Target gene expression in human skeletal muscle primary-cell culture was normalized to peptidyl-prolyl cis-trans isomerase B (PPIB) RNA levels. TaqMan probes were purchased as pre-validated assays for Pax7(Hs00242962_m1), MyoD (Hs00159528_m1), Myogenin (Hs01072232_m1), and PPIB (Hs00168719_m1) . Relative quantification of target genes was calculated using the ΔCT method. Derivation of the ΔCT equation has been described in Applied Biosystems User Bulletin no. 2 (P/N 4303859).t-test. Differentiation and the myogenic index, as well as RNA expression, were analyzed using repeated-measures ANOVA and a Tukey’s post hoc analysis to compare daily differences. Pearson’s correlations were used to explore relationships between SC function and age, bodyfat percentage, and BMI. The HSM effect is reported as percent change from control values. Data is presented as mean ± SEM and statistical significance was set at a p-value of ≤0.05. The samples were taken during two different Virginia Polytechnic Institute and State University, Internal Review Board-approved studies (#12–652 and #11–077). SC-culture approval was further granted under #14–1234. Written consent was obtained for both studies.One-way ANOVA was used to compare proliferation rates between the SedLn vs. SedOvOb and SedLn vs. SedOld with a Tukey post hoc test for multiple comparisons. SCs isolated before vs. following OVF and control vs. HSM samples were compared using a paired 2 (average (avg) 24.2 ± 0.6 kg/m2, avg bodyfat 21.3 ± 1.5%)  vs. overweight/obese , there were no differences in proliferation (p = 0.59) (p = 0.04), which was primarily driven by reduced spontaneous fusion (fusion prior to the addition of differentiation media) in the SedOvOb group (Influence of bodyweight/adiposity on SC function: SC cultures were obtained from 23 young (23.6 ± 0.7 years) participants with BMI ranging from 20–33 kg/m = 0.59) A. SedLn Ob group C. There Ob group D. A negaOb group E.2, p < 0.01) and body fat levels  compared to the younger SedLn group, but both groups participated in minimal physical activity    B. Withinp = 0.03, p = 0.05), and, thus, had higher rates of oxidative efficiency (p = 0.03) (The SedLn and SedOld groups achieved similar simple fusion (2+ nuclei) rates throughout differentiation C. Both g = 0.03) D. p = 0.03). There was no change in fasting blood glucose  or triglycerides . HDL , LDL , and total cholesterol  trended on changes but were not statistically significant. SCs collected after 4 weeks of OVF [p = 0.03)  A. Howeve = 0.03) B,C.p < 0.01) (p < 0.05) (p = 0.03). The effects of HSM exposure during the proliferative phase suppressed fusion after eight days of differentiation reducing simple and robust fiber nucleation by 15.7% (p = 0.02) and 16.5% (p = 0.03), respectively. Though there is a reported reduction in both proliferation and fusion prior to differentiation treatment it is possible that cells which attempted to spontaneously differentiate perished. Due to the proliferation assay only counting live cells, those that did not survive spontaneous differentiation result in a reduced measured proliferation.Effects of HSM on SedLn SC Function: SedLn (BMI 18–25) SCs treated with HSM demonstrated reduced proliferation (4.83 ± 1.95%) compared to control conditions ( < 0.01) A. HSM tr < 0.05) A,B. HSM 2, total FAO, and the ratio of complete to incomplete FAO (CO2:ASM) all improved (p < 0.05)  A,C,D. HS < 0.05) E. A meta < 0.05) E,F. Thisp < 0.05) of Pax7 expression (p < 0.01) and increased  expression of myogenin (p < 0.01), but with no change in MyoD compared to control SCs. After day one, HSM exposure had no effect on Pax7, MyoD, or myogenin expression.Pax-7, MyoD, and MyoG RNA-expression varied throughout proliferation and differentiation A–D. At dp < 0.05). In pre-OVF SCs, HSM treatment reduced proliferation by −5.35 ± 1.14%. Conversely, for SCs collected from the same individuals post-OVF, HSM exposure caused an increased proliferation rate of 7.17 ± 3.65% (p < 0.05) (p < 0.05), yet HSM treatment increased simple and robust fusion of SCs collected post-OVF  ( < 0.05) B. The sapost-OVF B,C.The primary findings of these studies are: (1) a high fat/hypercaloric feeding intervention in humans reduced cultured SC proliferation; (2) in sedentary participants age did influence in vitro SC function under control conditions, and (3) elevated concentration of fatty acids and glucose during SC proliferation have differential effects on SC function that may be influenced by the BMI, age, and diet of the SC donor. The effects of overfeeding on SCs may be linked to substrate availability as in vivo OVF and in vitro HSM treatments, resulting in similar changes to SC function.SCs may adapt to the substrate levels of their environment as demonstrated by the opposing responses to the HSM treatment of lean vs. overweight/obese SCs and SCs collected before and following overfeeding. Both BMI and bodyfat percentage showed some influence of SC function with overweight/obese SCs presenting with reduced fusion and bodyfat, negatively correlating with proliferation. These data, when taken with the OVF and HSM results from this study and previously demonstrated effects of DIO models ,32, showDonor age appeared to have no influence on in vitro function of SCs in humans after physical maturity. Donor age caused no differences in an SCs ability to proliferate, fuse, or differentiate into metabolically functional tissue. These results are contrary to findings from previous human and rodent models that suggest aging alters the function of SCs at their core, as aging has been shown to disrupt SC function in vivo ,50,51,52Previous studies have demonstrated that in vivo phenotypes of metabolic disease, such as insulin resistance ,34,55 anSC myogenesis is transcriptionally regulated through the sequential expression of key transcription factors (TFs): Pax-7   make it difficult for any human study to isolate the true effects of chronological aging. Large differences in adiposity between young and aged counterparts is a common complication seen in aging studies, as it is difficult to recruit a lean aged population. Even in the subject demographics for this work, there was a significant difference between the adiposity of the young and aged group. With the high prevalence of body fat differences in aging studies, we must ask if the differences currently attributed to age are truly due to the chronological age of the participants or could the variation be more accurately ascribed to the adiposity of the aged population.Perhaps one of the most intensive studies designed to elicit the mechanistic difference between young and old SCs is that of the work done by Roberts et al., published in 2011. This work found that Cyclin D1 and MyoD were determined to have different expressional patterns in young vs. aged SCs. In response to exercise, MyoD increased in the young group as expected, but there was no increase in the aged group.  While thThese results highlight the resiliency and adaptability of SCs, as age did not influence SC function. SCs were negatively affected by BMI, bodyfat, and overfeeding with reduced proliferation and fusion. While overfeeding causes a variety of systemic effects, such as inflammation and altered hormonal signaling, the results of the high substrate in vitro treatment indicate that changes to substrate levels alone are enough to alter SC function. This data suggests a reasonable viability for the use of dietary interventions to alter SC function. Age and BMI were influential in the SCs’ response to the substrate challenge, with SCs from both older and heavier donors preferring higher substrate. This is an indication that older and more obese populations may respond differently to dietary interventions designed to influence muscle function.


The graphene sensor tested with the LoRa nodes developed allows the detection of NO2 pollution in just 5 min as well as enables monitoring sudden changes in the background level of this pollutant in the atmosphere. The capability of the system of detecting both reducing and oxidizing pollutant agents, alongside its low-cost, low-power, and real-time monitoring features, makes this a solution suitable to be used in wireless AQM and early warning systems.During the few last years, indoor and outdoor Air Quality Monitoring (AQM) has gained a lot of interest among the scientific community due to its direct relation with human health. The Internet of Things (IoT) and, especially, Wireless Sensor Networks (WSN) have given rise to the development of wireless AQM portable systems. This paper presents the development of a LoRa (short for long-range) based sensor network for AQM and gas leakage events detection. The combination of both a commercial gas sensor and a resistance measurement channel for graphene chemoresistive sensors allows both the calculation of an Air Quality Index based on the concentration of reducing species such as volatile organic compounds (VOCs) and CO, and it also makes possible the detection of NO X, CO, and volatile organic compounds (VOCs) [According to the World Health Organisation, in 2016, household and ambient air pollution were responsible for seven million deaths ,4,5,6 ans (VOCs) ,15,16,17s (VOCs) . Thus, iThe conventional and most common techniques for air quality monitoring consist of stationary stations equipped with different instrumental techniques or manual sampling at different locations followed by analysis in specialised laboratories. These techniques can be very accurate but require the use of bulky, power-hungry, and expensive instruments ,20. ThusIn the last few years, several authors have reported the use of Wireless Sensor Networks (WSNs) for air quality monitoring systems ,22. In tAmong the promising technologies used in the LPWAN space are Narrowband Internet of Things (NB-IoT), Sigfox from Sigfox, Labège, France, and LoRa. While NB-IoT presents the largest data rate and payload size of these three technologies, it operates in licensed Long-Term Evolution (LTE) frequency bands. Thus, the use of NB-IoT was not considered to keep costs low. The Sigfox presents a higher transmission range than LoRa , but Sigfox is deployed by network operators, so users need to pay subscription charges for every node installed. Moreover, Sigfox transmits messages multiple times to improve reliability, resulting in high energy consumption. Hence, LoRa and LoRaWAN protocol were selected to develop the network ,50,58,59LoRa is a spread spectrum modulation technique derived from chirp spread spectrum (CSS) technology. This physical layer technology works in the unlicensed sub-GHz industrial, scientific, and medical (ISM) band. Depending on the spreading factor (SF) and the channel bandwidth (BW) settings, the data rate supported by LoRa varies from 300 bps to 50 kbps. The transmission power (TP), SF, coding rate (CR), and preamble length define the signal airtime and power consumption .LoRaWAN is a media access control (MAC) protocol for wide area networks designed to allow low-powered devices to communicate with Internet-connected applications over long-range wireless connections. Innovative LoRaWAN features include support for redundant operation, geolocation, low-cost, and low-power applications. Devices can even run on energy harvesting technologies  enabling the mobility and ease use of IoT. LoRaWAN protocol provides origin authentication, integrity protection, replay protection, and full end-to-end encryption ,60. The 2), released to the atmosphere mainly from automotive exhausts [2 at trace levels [The aim of the present paper is to discuss the development of an IoT implementation for inexpensive indoor air quality monitoring  and real-time pollutant detection. This consists of a wireless sensing network in which its sensing nodes include both commercial and lab-made  cloud server, the gateway was ready to forward the uplink and downlink messages sent from the nodes to the server and vice versa. Nodes perform measurements, codify the information, and send the data at every sampling period and then go to deep sleep mode. The data received in the cloud server is processed and stored for later visualisation. Front-end web and desktop applications were developed to access and visualise the data stored in the cloud server. The sensor network is devised for monitoring indoor air quality (nodes were distributed in different locations at the University campus), the gateway selected was The Things Indoor Gateway (TTIG) from The Things Industries. TTIG is a low-cost, fully compliant LoRaWAN gateway, which uses Wi-Fi as backhaul. It has a Semtech SX1308 LoRa chipset from Semtech Corporation, Irvine CA, USA, which presents a receiver sensitivity of −140 dBm and uses the 868 MHz frequency band (in the European Union). This indoor gateway has an integrated antenna and presents the Federal Communication Commission (FCC) and European Economic Area (CE) certifications. The software running on the gateway makes it act as a bridge between the LoRa nodes and TTN cloud server.LoRa nodes b developThe sensing board a developDD main supply voltage that ranges from 1.2 to 3.6 V, which matches with the supply voltage of the microcontroller used. The IAQ value calculated using this sensor and the Bosch Sensortec Environmental Cluster (BSEC) library gives an indication of the total amount of VOCs and other reducing gases such as CO present in the studied atmosphere. The output is based on an intelligent algorithm that includes not only the resistance value of the metal oxide sensor the BME680 includes, but also humidity, temperature, and the measurement history values stored in the sensor state. The sensor state is stored after each measurement to be used in the sensor calibration for later IAQ value calculations. The sensor calibration typically encompasses up to 4 days of measurements. This index ranges between 0 and 500  [The BME680 is a 4-in-1 digital low-power gas, pressure, temperature, and humidity sensor, which with the proper configuration and software libraries, presents a direct index for air quality (IAQ) output. The sensor has a Vy index) . Some pry index) ,66,67,68The program running on the LoRa nodes was developed using C language in Arduino IDE from Arduino, Somerville, MA, USA. Once the nodes are powered up, reset, or woken up from deep sleep mode, the first step is to initialise the BME680 sensor and the ADC channel for the resistance measurements of the lab-made sensor. If the microcontroller unit (MCU) is reset or just powered up, the second step is to perform a measurement with the sensors. On the other hand, if the MCU wakes up from deep sleep mode, the previous state  request.For developing the front-end application, a set of Open-Source Software (OSS) was used, thus, saving money from the overall cost of the solution by avoiding licensing and software maintenance fees. The visualisation data solution presented in this section consists of a local server that stores the sensor data locally and makes it available to be visualised in a web service accessible from any device having internet access. The server could be deployed in any system running a Linux distribution . Telegraf  is a server agent used to collect sensor data arriving to the TTN Message Queue Telemetry Transport (MQTT) broker through an MQTT consumer. With this purpose, a Mosquitto  client is set to connect with the TTN broker. The data collected by the Telegraf instance is stored in InfluxDB (from InfluxData), which is a time series database. For the visualisation of the data, Grafana was selected, which is an analytics and monitoring solution from Grafana Labs, New York, NY, USA. A graphene-based gas sensor was fabricated by preparing a solution with 1 mg of graphene nanoplatelets from Strem Chemicals, Inc., Newburyport, MA, USA, dispersed in 10 mL of toluene. Afterwards, graphene nanoplatelets were exfoliated during one hour at high frequency (35 kHz) by using an ultrasonic bath . Then, the solution was deposited onto the screen-printed platinum electrode area of an alumina substrate by the spray-coating technique. During this deposition, the substrate was placed in a hotplate at 125 °C in order to obtain a more homogeneous sensitive layer. Finally, the sensor was dried in an oven at 130 °C to ensure the complete removal of the solvent. A picture of the coated alumina substrate is shown in the supporting information .The graphene used was characterised by several techniques, such as Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field-effect scanning electron microscope (FESEM), and high-resolution transmission electron microscopy (HR-TEM).The graphene crystallinity was evaluated using a Raman spectrometer from Renishaw, plc.  coupled to a confocal Leica DM2500 microscope from Leica Microsystems GmbH, Wetzlar, Germany. The laser employed had a wavelength of 514 nm. The chemical composition of graphene was obtained by using an XPS spectrometer from SPECS GmbH, Berlin, Germany equipped with a non-monochromatic X-ray source (Al). Graphene morphology was studied using a FESEM and HR-TEM. In particular, graphene porosity and layer homogeneity were studied using a FESEM from Carl Zeiss AG, Oberkochen, Germany; meanwhile, graphene sheet sizes were observed via HR-TEM from Jeol Ltd., Tokyo, Japan.2/g and electrical conductivity of 107 and 102 S/m . Regarding the lateral size, different graphene nanoplatelets are stacked with an interplanar distance of 3.35 Å, while the overall graphene nanoplatelet aggregates have a thickness of a few nanometers.According to the graphene manufacturer, this nanomaterial has a surface area of 750 m−1, which indicates the presence of defects  in the crystalline structure. Conversely, the G band located at 1572 cm−1 reveals the stretching of C–C bonds, which are related to in-plane oscillations of sp2 configuration [D/IG is commonly used as an indicator of the crystallinity in carbon nanomaterials [D peak), being translated in highly crystalline graphene [D/IG ratio of 0.79, indicating moderate graphene crystallinity. However, this fact is interesting from the gas sensing point of view, because these defects usually act as active sites for gas interaction and are also useful for further graphene functionalisation.A Raman analysis was conducted in order to study the graphene crystallinity. guration . In consaterials . In thatgraphene . However2 carbon configuration. Nevertheless, according to the low crystallinity registered in the Raman analysis, a significant peak related to amorphous carbon or sp3 configuration can be found at 285.1 eV [2) functional groups grafted at the graphene surface.Additionally, an XPS was performed to obtain the elemental quantification. Regarding this, the graphene employed presents 89.99, 9.46 and 0.55% of carbon, oxygen and nitrogen, respectively. The fitting analysis of the C1s peak, centred at 284.4 eV, is represented in 285.1 eV . Further285.1 eV ; meanwhi285.1 eV . FinallyImages obtained by field-effect scanning electron microscope (FESEM) show a high porosity at the graphene surface a, which The characterisation of the gas sensing properties for the graphene sensor was performed in two different tests. First, laboratory conditions were set to test the sensor performance under fully controlled conditions, and next, real conditions were simulated to check its reliability for real-life applications. Results obtained from sensor characterisation tests run under laboratory conditions can be found in the supporting information.3. NO2 and CO calibrated cylinders of 1 ppm and 100 ppm, respectively , mixed with ambient air were used to set the desired gas concentrations. Gas flows were set by using a mass-flow controller system (EL-FLOW®) from Bronkhorst High-Tech, Ruurlo, Netherlands, and Flow View and Flow Plot software from the same company were employed, while a rotameter was used to control the ambient air flow. A total flow of 600 mL/min was kept across the chamber. The flow established was selected to simulate a gas diffusion process through the chamber avoiding the direct flow incidence on the sensors, which can influence the measurements. According to the inner volume of the acrylic chamber and the total flow through it, the time needed to renovate completely the atmosphere inside the chamber was about 8 min. Hence, the gas pulses implemented were programmed with a separation significantly higher than 8 min. Results from this test are shown and discussed in The tests performed under close to real conditions were implemented using the graphene sensor connected to the LoRa node resistance measurement channel, which was placed in an acrylic chamber with an inner volume of about 4900 cm2 carbon configuration, is usually reported as a material with very poor sensitivity [3 carbon configuration and oxygen functional groups. Thus, graphene nanoplatelets show significant sensitivity to nitrogen dioxide (NO2) [2 (an electron-withdrawing species), a decrease in the film resistance is recorded due to the increased concentration of positive charge carriers.Pristine graphene, with its characteristic spsitivity . Howeverde (NO2) . This gade (NO2) . Therefo2 cannot be completely ruled out, which involves the exchange of higher amounts of charge between adsorbed gas species and the sensor surface (see Supporting Information).Considering the room temperature working conditions, the sensing mechanisms are probably ruled by the physisorption of gas molecules involving small charge transfers between nitrogen dioxide and the sensor surface. However, the slow baseline recovery indicates that the chemisorption of NO2) due to the exposure of the sensitive film to air should be considered. Adsorbed atmospheric oxygen could eventually withdraw free electrons from the conduction band of graphene, resulting in an electron-depleted surface layer and the chemisorption of oxygen species [2 [In this regard, the physisorption of molecular oxygen  than for CO (0.01|e|) [2 and H2O are simultaneously present, an additive effect is shown due to their electron-withdrawing behaviour over a mild p-type semiconductor such as graphene [2 response in humid atmosphere induces a larger increase in the conductivity. This fact is derived first from the charge transfer from graphene to water molecules when they are adsorbed in the sensor surface. Then, the subsequent water-mediated adsorption of NO2 can occur, further increasing the conductance change. This mechanism is especially worthy in measurements at room temperature. Indeed, Hall measurements have revealed that water molecules act as electron-withdrawing agents at room temperature [2O and CO molecules could significantly reduce the conductance changes recorded when these two analytes are present simultaneously. Nevertheless, the integration and combination of graphene sensors with other chemoresistive sensors such as metal oxides offer a great opportunity for better discriminating between electron donor and withdrawing gases.Conversely, CO measurements reveal a lack of sensitivity for the bare graphene sensor. This agrees with theoretical calculations that report higher charge transfer (Q) upon adsorption for NO0.01|e|) . Nitroge0.01|e|) . Howevergraphene . In otheperature , while CThe LoRa sensor network was deployed in different locations at the University Campus with the purpose of testing the communication performance between different nodes and gateway configurations. Thus, the indoor gateway position was set in one location, while nodes were placed at different distances from the gateway, using different transmission powers. All the combinations used the rest of the network configuration parameters, namely carrier frequency (CF), BW, SF, CR and preamble length were set fixed. The CF used was 868 MHz, which is one of the two license-free sub-gigahertz radio frequency bands for Europe. The bandwidth was established in 125 kHz, thus ensuring enough bitrate and sensitivity for the detection of the signal. The spreading factor value of 7, which is the lowest possible, linked to a coding of 4/5 to allow the minimum time on air of the signal, and consequently a lower power consumption. The preamble length was also selected as the lowest possible value to guarantee the lowest power consumption. During the test period (around 2 weeks for each pair TP and distance), the weather conditions were changing, and this is reflected in the package loss percentage shown in Locations were selected according to two different scenarios. In the first one, the nodes were placed near the gateway, which were separated one from each other by several offices inside the same building. This configuration allows avoiding interferences provoked by unfavourable weather conditions, while the transmission power used can remain low, thus saving power without affecting the network performance. In the second location, the nodes were placed at 115–130 m away from the gateway (in different buildings), with non-straight sight and structural obstacles between them. This ensures the analysis of the network performance when conditions are not the most favourable for the communication. The transmission power was set at 12 dB, 14 dB, and 20 dB to compare the RSSI and package loss values obtained when the TP increases. All RSSI values obtained for the pairs distance–transmission power were higher than the sensitivity of the gateway. For nodes placed in the same building, the package loss rate was less than 1% using a TP of 12 dB. This means just 1 or 2 package losses during 24 h of measurements in the worst case. For longer distances, the TP was increased from 12 to 20 dB (which is the maximum possible) to compare the performance of the network. Referring to Although nodes have been powered up through a standard wall socket, all the design and configuration characteristics were considered to use the nodes in a low-power mode. This enables powering up the nodes employing batteries. Using a TP of 12 dB and the rest of transmission parameters as mentioned above, the average power consumption for 1 h is about 1 mA. Thus, considering the use of a 2200 mAh battery, and assuming a total discharge of 85%, the estimated battery lifetime would be about 75 days.The network is fully scalable  without the need of modifying any parameter on the gateway side. Thus, after the first deployment, the gateway can run continuously, and just each new node should be registered on the cloud server in order to assign the unique authentication parameters it needs to become part of the network. This allows enlarging the number of nodes at any time without affecting the global network performance.2 at concentrations near the threshold limit value (TLV). With that, it was possible to simulate events of gas leakage or sudden increases in concentration when the concentration changes from the background level of the target species in the atmosphere to values above the TLV established by the European US agencies [2 concentration was set at 200 ppb. Pulse duration randomly varied between 5 and 15 min. As measurements were performed under real conditions, the relative humidity (RH) and temperature were variable during the test period, with average values about 50% and 30 °C, respectively.Both commercial (BME680) and lab-made (graphene) sensors where placed in the LoRa node and exposed to gas pulses of CO or NOagencies ,85. For Results obtained for exposures to CO at 35 and 50 ppm during periods between 10 and 15 min show how the BME680 MOX sensor resistance and IAQ value follow the changes in gas concentration. In the same way, after every gas pulse, the BME680 sensor resistance starts recovering its initial value.On the other hand, the graphene lab-made sensor resistance does not experience a significant variation during the exposures to CO. This does not mean that the sensor resistance remains constant, but the resolution of the resistance measurement channel, given by the analog-to-digital converter (ADC) resolution, is not high enough for detecting the very small resistance variations suffered by the graphene sensors in the presence of CO at the concentrations and pulse durations tested.2 pulses of 200 ppb applied during periods of 5, 10, and 15 min.2 changes, the IAQ value does not reflect this variation, or even worse, it decreases in the presence of this pollutant gas. This is an expected result, as the BME680 is meant to be used for detecting VOCs and CO, which are reducing gases, while NO2 is an oxidising gas.The results presented in 2 pulses is fully detectable by the readout circuitry implemented in the nodes. Resistance variations produced during the gas exposure have values of about 30 Ω for a 5-min exposure period. This variation is at least three times the noise background level and resistance drift when the sensor is exposed to the background air. This result makes the system suitable for the detection of a sudden increase in NO2 concentration.Conversely, the graphene lab-made sensor response to NOThe BME680 sensor is used as a general-purpose gas sensor through the IAQ value, with poor selectivity, and the IAQ value calculated is just negatively affected by reducing gases. The additional resistance measurement channel designed allows using a wide range of gas sensitive materials, thus giving selectivity and widening the set of target gases and applications where the sensor network can be applied. Further gas sensing response results can be found in 2 background level present in the atmosphere. The sensor response was compared with the historical data registered by the automatic stations from the Network for the Surveillance and Forecast of Atmospheric Pollution in Catalonia obtained from [2 background level and the NO2 concentration registered every 1 h by the nearest air quality station to this node in Tarragona. The evolution of ambient humidity and temperature during this test is shown in 2 concentration data obtained from these stations. Finally, a 36 h continuous measurement experiment was conducted one month later than the one shown in 2 levels in the Tarragona area. These results are shown in 2 concentration in the ambient.For longer exposure time analysis, the graphene sensor was left for about 1 day connected to the LoRa node (placed indoors) reacting with the NOned from . Figure 2 concentration increased in the Tarragona area  correlate very well with episodes in which the outdoor NO2 in the range from 50 to 250 ppb obtained for the graphene sensor. These results indicate that our system shows potential for performing a quantitative analysis, but further work beyond the scope of this paper is necessary.If a quantitative rather than a qualitative analysis of nitrogen dioxide would be envisaged using the graphene sensor and the wireless network discussed here, the use of heating for periodically restoring the sensor surface and recovering its baseline would be needed. In addition, performing a calibration procedure would be needed as well. This work presents the development of a LoRa-based, scalable, low-cost, and low-power sensor network for air quality monitoring and gas leakage events detection in real time. The ability of the network of hot-plugging nodes allows the continuous operation and its easy scalability by just registering nodes on the cloud server application.2 . The limitations associated to the use of the IAQ value when an oxidising gas is present can be overcome using the lab-made graphene sensor. Graphene and the commercial sensors used in the sensor nodes development allow identifying the presence of pollutant reducing and oxidising gases through the IAQ value variation and the qualitative information obtained from the resistance variation of the graphene sensor, respectively. The graphene sensor developed not only enables the detection of sudden increases in NO2 concentrations but also makes the system suitable to follow the surrounding NO2 concentration trend in ambient air. The possibility of functionalising the graphene sensor presented here or the use of other gas sensitive materials can help modify the selectivity to different target gases, making this system suitable for being deployed in different application scenarios.The commercial gas sensor used enables the detection of reducing gases such as VOCs and CO, and the calculation of an Index for Air Quality according to the total concentration of these pollutant species in the surroundings. However, this sensor is not able to give a proper IAQ value in the presence of oxidising pollutant gases, as the IAQ value decreases when the sensor reacts with NODespite the use of an inexpensive indoor gateway and 2 dBi omnidirectional antennas at the nodes, and having placed the nodes and gateway at different locations and distances, the RSSI values obtained were always above the sensitivity level, and the package loss rate was under 7% for every configuration tested.2 concentrations variation in a qualitative way, but it also shows the evolution of ambient humidity and temperature.The user-friendly web service developed for accessing the data remotely not only allows checking the values of the IAQ and the NOFurther graphene functionalisation  is possible to enhance the results presented here. In addition, not limited to this, different gas sensing materials  can be also adapted to the sensing nodes when other requirements are needed. This means that our sensing nodes present many possibilities to be improved and high versatility for being employed in different applications.2 concentration.Future work will be focused in the quantitation of the target gases measured with chemoresistive sensors integrated in the sensing nodes. For example, by using heating for periodically restoring the sensor surface and recovering the baseline and by employing a calibration procedure, the graphene sensor could be used for quantitatively determining NO


Asian Americans (AAs) are frequently diagnosed with dementia in advanced disease stages and have difficulty accessing services. The NYU Center for the Study of Asian American Health, set out to culturally adapt The Kickstart-Assess-Evaluate-Refer (KAER) framework to support earlier detection of dementia in AA communities. Working with Bangladeshi, Chinese, and Korean senior centers, we used a participatory action approach to assess cultural relevancy, usability and acceptability of KAER to improve timely diagnosis and access to care. We found that community-based organizations (CBOs), not physicians, were often “first responders” in identifying and managing dementia. However, CBO staff felt unprepared to “Kickstart” discussions, found certain KAER questions were not culturally appropriate, and encountered barriers in communicating their concerns to physicians. Adaptations to KAER can maximize its impact and reach in AA communities. Suggestions include group education, as opposed to individualized screening, and stronger linkages between physicians and CBOs to ensure care continuity.


Pseudomonas fluorescens which diversifies into coexisting niche‐specialist morphotypes. We first evolved replicate populations for ~40 generations and then isolated evolved genotypes. In a series of competition trials, we determined if using coevolved versus random genotypes affected the relative performance of “communities” of single and multiple genotypes. We found no effect of coevolutionary history on either genotype fitness or community performance, which suggests parallel (co)evolution between communities. However, fitness was enhanced by the presence of other genotypes of the same strain type , indicative of local adaptation with respect to genetic background. Our results are the first to investigate the effect of (co)evolution on the outcome of coalescence and suggest that when input populations are functionally similar and added at equal mixing ratios, the outcome community may not be asymmetrically dominated by either input population.Community coalescence, the mixing of multiple communities, is ubiquitous in natural microbial communities. During coalescence, theory suggests the success of a population will be enhanced by the presence of species it has coevolved with (relative to foreign species), because coevolution will result in greater resource specialization to minimize competition. Thus, more coevolved communities should dominate over less coevolved communities during coalescence events. We test these hypotheses using the bacterium  Serial 100‐fold dilutions (60 μl into 6 ml KB) took place every 4 days for a total of 20 days , microcosms were paired between and within strains. This resulted in three blocks of four communities (two wild‐type and two LacZ populations in each block) from which coevolved and randomly assembled communities for the competition trials were designed. Within each block, competition trials were designed for all combinations of coevolutionary history (coevolved or randomly assembled) and levels of morphotype diversity  and subsequently plated onto KB agar containing 40 μg/ml of X‐gal . Competition trials were inoculated into KB medium under the same conditions as the initial serial dilutions. After 4 days, cultures were frozen as above and subsequently plated on agar containing X‐gal where LacZ colonies can be distinguished by their blue colour. Morphotype density (CFUs/ml) was calculated by counting the number of colony‐forming units (CFUs) after 2 days of growth at 28°C. Relative fitness was defined as the fitness of one LacZ morph versus the same wild‐type morph . Relative community performance was defined as the performance of the whole LacZ community relative to the competing wild‐type community. Both relative fitness and community performance were calculated from the ratio of the estimated Malthusian parameters, mLacZ:mwild‐type, which were calculated as m = ln(N1/N0), where N1 is the final density and N0 is the starting density  with optical density normalized to ~0.1 OD2.3R  was added as a potentially interacting factor to look for asymmetric effects between morphs. We then selected trials where SM and WS morphotypes were present in both LacZ and wild‐type communities to investigate whether coevolved communities were more successful than randomly assembled communities during community coalescence. In this model, coevolutionary history of LacZ and wild‐type communities were included as potentially interacting factors.R package “emmeans” . Model simplification was done using likelihood ratio tests, and Tukey's post hoc multiple comparison tests were done on the most parsimonious model using the ” Lenth, . We also3p‐values > 0.05). As the presence of coevolved genotypes had no impact on genotypic relative fitness, we then determined whether LacZ/wild‐type genotypic fitness was influenced by the presence of additional LacZ/wild‐type genotypes per se. The results were inconsistent across genotypes  from different communities was not influenced by the presence of coevolved genotypes versus a random genotype or the absence of additional genotypes  whereas LacZ communities were dominated by SM .Given that LacZ SM fitness was influenced by whether a LacZ or wild‐type WS was present, we investigated in more detail diversification of populations during the 20‐day coevolution period. Across all populations and consistent through transfers, wild‐type communities were dominated by WS morphotypes . However, this effect was highly inconsistent, with only LacZ SM benefiting from the presence of LacZ WS. Unsurprisingly, given the genotype‐level results, coevolutionary history did not increase community cohesion and performance. Our results have implications for the niche‐packing hypothesis with respect to how resource partitioning occurs across allopatric populations and how evolutionary interactions within communities influence community coalescence.Niche‐packing and resource specialization should be optimized when individuals have coevolved together, as coevolution drives adaptive radiations and character displacements  suggests that SM benefited from WS by exploiting additional resources from this morph. Previous research on this experimental system shows that SM can invade WS biofilms , suggesting a lack of evolved interactions between morphs as WS fitness is independent of its community evolved in parallel across allopatric communities  of communities into fresh media, an abiotic environment that both strains evolved in for 20 days. Thus, priority effects which can result in the resident community dominating are minimized evolutionary history in the outcome of community coalescence. This allowed us to control the complexity in the experiment, but most importantly guaranteed us genotypes that came from a coexisting population that had shared a (co)evolutionary history. This approach has been used previously to study evolution and the maintenance of ecological diversity evolution occurs in parallel. The importance of these specific (co)evolutionary relationships in driving performance at the community level highlights the need to consider interactions at lower organizational levels when studying community coalescence.D.P., A.B. and M.C. conceived the study and designed the experimental work. D.P. and M.C. conducted the experiments and D.P. analysed the data. All authors contributed equally to the writing of the manuscript. Click here for additional data file.


The results of both methods are compared with experimental data. We discover that metallic screening by the Pt layer converts the square-root dispersion of the Dirac plasmon into a linear acoustic-like plasmon dispersion. In the long-wavelength limit, the Pt d electron excitations completely quench the The excitation spectrum in the region of the intraband (Dirac plasmon) and interband ( Epitaxial growth on graphene represents the most suitable method to achieve large-scale samples of graphene with high crystalline quality. Moreover, graphene/metal contacts are unavoidable components in each graphene-based device. An abundant number of applications are based on collective electronic excitations, i.e., plasmonic modes. The intensity and dispersion relations of electronic excitations in supported graphene depend on the strength of the graphene interaction with the substrate ,5,6,7,8.d electrons on the ultraviolet (UV) graphene plasmons, such as the interband d states [Another relevant open issue regarding plasmons in graphene/metal interfaces is related on the influence of screening by the metallic d states ,28,29 and states ,7,8. ThiThe EELS spectra in the MIR/NIR range are dominated by the Dirac and acoustic plasmons ,30, whical atoms ,18,19,20al atoms , typicalConversely, the UV plasmonic response of graphene is dominated by a peak termed ubstrate ,4,8. The spectra ,32,33 an spectra ,34, seveansition ,34,35. IIn this work, we present a joint experimental and theoretical study of electronic excitations in graphene monolayer deposited on a Pt-skin-terminated PtOn the other hand, for the high-energy e fluids ,36. Suche fluids ,38. Thise fluids .e is the electronic charge, m is the mass of electron. The graphene/Pt-skin-terminated PtThe rest of the paper is organized as follows. In Monolayer graphene was grown on Pt-skin terminated Pt in Ref. . Angle-rThe system we study here is shown in z direction) are The crystal structure of the Pt-skin surface is modeled by 4 atomic layers, with three atomic layers representing the PtQuantum Espresso (QE) package [The ground-state structural optimization and the electronic density calculations were performed using the  package ,42. The  package . The str package . The groint mesh , respect[h=3.3 Å .h results in negligible electronic overlap between the graphene layer and the topmost Pt layer, allowing us to perform separate calculations of the non-interacting electron response functions of graphene and the Pt-skin, thereby considerably reducing the unit cell size and saving the computational time and memory requirements. The graphene and the Pt-skin non-interacting electron response functions areThe large equilibrium distance ions areχi0=v in =w=v/, the, the5), ith oscillator, and Our calculations show that, in the long-wavelength regime, illators ,(9)ϵPt frequencies, the Pt-skin surface responds instantaneously  ,54, wherQ, it exhibits a square-root dispersion relation. This transitional behavior of the  in Ref. , in unsuin Refs. ,55, and It can be noticed in ubstrate , suggestQ, the effective dielectric function in the long-wavelength limit becomesThe ic model , which gction in  and retaQ. When the Pt-skin surface is present, even though at frequencies Without the Pt-skin surface   Dirac plasmon in doped graphene, and the high-energy (UV)


Graphene with atomic thickness possesses excellent mechanical and electrical properties, which hold great potential for high performance pressure sensing. The exposed electron of graphene is always cross-sensitive to any pollution absorbed or desorbed on the surface, from which the long-term stability of the graphene pressure sensor suffers a lot. This is one of the main obstacles towards graphene commercial applications. In this paper, we utilized polymethylmethacrylate (PMMA)/graphene heterostructure to isolate graphene from the ambient environment and enhance its strength simultaneously. PMMA/graphene pressure sensors, with the finite-depth cavities and the through-hole cavities separately, were made for comparative study. The through-hole device obtained a comparable sensitivity per unit area to the state of the art of the bare graphene pressure sensor, since there were no leaking cracks or defects. Both the sensitivity and stability of the through-hole sensor are better than those of the sensor with 285-nm-deep cavities, which is due to the sealed gas effect in the pressure cavity. A modified piezoresistive model was derived by considering the pressure change of the sealed gas in the pressure cavity. The calculated result of the new model is consistent with the experimental results. Our findings point out a promising route for performance optimization of graphene pressure sensors. Graphene, as natural atomic material, is an ideal option as a sensing membrane of pressure sensors. Pressure sensors are used in a tremendous range of applications, from our daily life to industrial monitoring ,2. The cThe graphene-based piezoresistive pressure sensor has been demonstrated by several research groups worldwide in recent years. The first prototype was built by J. Scott Bunch et al.  to test In this work, we applied our polymer-assisted scheme to two different pressure sensor structures to study the sealed gas effect in the pressure cavity. One is the most reported structure, in which the pressure cavity has a finite depth. The other is with a through-hole design. Their performances were measured and analyzed. An improved piezoresistive model was built to explain the increased performance in the sensor with the through-hole cavity.To study the effect of the sealed gas in the pressure cavity, PMMA/graphene pressure sensors with a 285-nm-deep cavities and through-hole cavities were designed on the same chip. The fabrication process flow is schematically depicted in First, the silicon substrate, capped with thermally grown 285 nm-thick SiO2, was cleaned and pretreated with Hexamethyldisilazane (HMDS) to modify its surface hydrophilicity, which was followed by spin-coating a layer of AZ1500 photoresist. Standard ultraviolet lithography was applied to transfer the pressure cavity pattern to the photoresist. The cavities of 285 nm depth were etched by buffered oxide etchant (BOE). To make the through-hole, we introduced twice reactive ion etch (RIE) processes, since the substrate was too thick to etch through. Firstly, a new layer of photoresist was spin-coated after removing the old resist. Then, only the through-hole cavities were patterned. After the first RIE process, about 40-μm-thick Si in the cavity was removed. Then, it was turned upside down to apply the second RIE process. A thicker photoresist with 7 μm thickness was used as a mask for a long time RIE. Rectangle windows with size larger than the through-hole cavity regime were patterned. After the second RIE process, all cavities connected to the backside windows formed through-hole structure, as shown in 3) to remove the copper, followed by repeatedly rinsing in deionized water (DI). Then, the cleaned PMMA/graphene (PMMA/Gra) membrane was scooped up by the prepared substrate and baked at 150 °C for several minutes to remove the interface water between graphene and the substrate, and also make the membrane stick to the substrate surface well. The transferred membrane is shown in Since graphene is only one atom layer, protecting graphene from cracks and collapse is one of the most important issues towards high yield fabrication and practical applications. Herein, instead of removing the PMMA support layer after transfer, as described in the traditional transfer process in most articles, we kept the thin layer of PMMA forming PMMA/graphene heterostructure to enhance the suspended membrane strength. The transfer flow of PMMA/graphene heterostructure is presented in 2 plasma etching, the LOR and AZ 1500 bilayer was removed by rinsing in 3038 solvent. Finally, the sample was cleaned in DI water and blown dry gently using N2 gas. To pattern graphene, we introduced a bilayer resist as the mask, which consists of a LOR 10A resist layer and a AZ 1500 resist layer. Experimental tests found that the LOR-10A resist is well compatible with PMMA, while AZ 1500 will attack the PMMA layer. Thus, a layer of LOR-10A resist was inserted between AZ 1500 and PMMA for isolation. Developer 3083 was well chosen as both a developer and remover for the bilayer mask because it is a good remover for LOR. The graphene pattern was transferred by ultraviolet lithography. After OAll the processes above are compatible to the traditional CMOS process and suitable for large-scale fabrication, which holds great potential to bridge lab research to commercial application. Following our fabrication scheme, our PMMA/graphene pressure sensor fabrication achieves an almost 100% yield.Our measurement scheme is illustrated in During several venting and pumping cycles, the time-dependent responses of both sensors were monitored, as shown in S is the sensitivity, R the initial resistance. The sensitivity of the PMMA/Gra pressure sensor is calculated to be S = 7.42 × 105 kPa−1. For quantitative assessment, we kept the pressure constant at several steps and measured the time trace of each sensor a. Under As simulated in reference , the appWe attribute the sensitivity difference to the volume change of the sealed gas in the 285-nm-deep pressure cavity. By taking the deflection-induced volume change into consideration, an improved piezoresistive model is derived in this paper. R to the strain ε:First, the gauge factor (GF), a measure of piezoresistive effect, is defined as the ratio of relative change in electrical resistance According to the theoretical analysis and experiments in reference , the GF P and deflection d for a circular membrane is given as [t and r are the graphene thickness and radius, respectively, E and υ are Young’s modulus and Poisson’s ratio of graphene, respectively, d is the deflection in the center of the membrane. Since the deflection is much smaller than the diameter of the suspended graphene membrane, an approximative relation of the strain and the deflection can be obtained [The relation of the pressure given as : (3)|P−Pobtained .(4)ε≈2dd, we get the classical piezoresistive model as: By plugging Equations (2) and (4) into (3) to substitute the parameter d. Herein, we accurately calculate the volume change In most literature, the hange ΔV  in cavitAccording to the equation of state of a hypothetical ideal gas (Boyle’s law) , the preThe relative resistance change ratio The high-yield fabrication process by utilizing PMMA to support and seal the atomic graphene sheet was applied to two different pressure sensor structures: through-hole type and finite-depth type. The PMMA/graphene pressure sensor with the through-hole cavity operates as fast as the commercial pressure sensor. Even though the PMMA/graphene membrane is hundreds of times thicker than single layer graphene, our sensor exhibits a comparable sensitivity per unit area to the state of the art of the graphene pressure sensor without the PMMA supporting layer, which hints that the gas leakage from cracks or defects of the graphene sheet severely affects the device performance. Further, the performance of PMMA/graphene pressure sensors with a 285-nm-deep cavities and through-hole cavities are comparatively studied. The device with the 285-nm-deep cavity shows worse sensitivity and stability due to the volume-induced pressure change of the sealed gas in the pressure cavity. By taking the pressure change into consideration, an improved piezoresistive model is derived. The results deduced from the new model are consist with our experimental results. Our findings point out a promising route for better performance of graphene-based pressure sensors.