Part 2: Health apps, wearables, and sensors: The advancing frontier of digital health

The world's first flying bicycle flew on November 9, 1961, when Derek Pigott of the University of Southampton flew in a bicycle with an airplane-like body. It was called the Southampton University Man Powered Aircraft (sumpac). Derek furiously pedaled the air-bike to get it off the ground. It then flew 1.8 meters (about 6 ft) above the ground over a distance of 64 meters (210 ft). While the flight was short and slow, it still does not change the fact that it was the first bicycle to fly and at the same time, the first human-powered flight.
我敢保证,魔兽霍华德从未用过生长激素,但在其他人看来,他似乎用了很多。自从离开高中进入NBA后,霍华德的体形似乎翻了一番。
But Michael DeFranco, chair of Baker & McKenzie’s M&A practice, hailed the Chinese group’s investment in developed economies.
If you've got children, I understand that this isn't always possible. Children should always come first. But if you don't show up for your classes, you're not getting that education we discussed in No. 1.
过去十年中,只有3颗10克拉级且硬度相当的鲜彩蓝钻被拍卖,3颗都未达到12克拉,而且有瑕疵。
宝能投资集团董事长姚振华是2015年财富榜的黑马,他的财富在一年之内上升了820%,达到172亿美元,使他上升到财富榜第四位。
Premiered on Jan 29, the drama received 7 points out of 10 on the country's popular review website Douban.
Sweden’s Proponent of ‘Feminist Foreign Policy,’ Shaped by Abuse
根据这份由互联网薪酬调查及报告提供商中国薪酬网发布的调查显示,清华大学2017届毕业生平均月薪达9065元。
新兴市场投资者不需要被提醒美联储(Fed)对新兴市场资产的重要性——不是吗?
Apart from India, other BRICS nations -- Brazil, Russia, China and South Africa -- cut down their holdings of American government securities.
今年的排行榜包括90个管理学硕士项目,创历来最高纪录,多于2015年的80个。
['θ?:tful]
While still on stage, Beatty blamed the epic mishap on being given the wrong envelope, saying he had seen the name Emma Stone from 'La La Land' when he opened his envelope.
人力资源机构罗伯特?哈夫国际公司(Robert Half International)最近针对4,000名企业高管进行了一项调研。其中有88%的人预计,未来一年,公司的业务将有所好转。这不失为最鼓舞人心的消息了。
China’s commercial aerospace ambition has long been known, but a few recent milestones are bringing it closer to realization.
There are at least 600 island owners in China, Lin Dong, founder of the China Island Owners Association, estimates.
As for the worst job of 2013? Newspaper reporter bumped last year's loser, lumberjack, for the ignominious distinction.
这张专辑等于是一次直截了当的暗示,提醒着我们,不论什么时候,只要霉女王想要,她就能拿回自己在流行音乐界的领先地位。
5.Effective decision makers
其他两家手机制造商OPPO和vivo的增长率都超过了100%,在2016年分别出货9940万台和7730万台。
A jailed con artist who falls in love with another inmate and escapes prison multiple times could only be the work of fiction, but this is more or less the real story of Steven Jay Russel. Much like his film counterpart, played by Jim Carrey, Russell was originally sent to prison for fraud. He escaped his first sentence to be with his partner Jim Kemple, who at the time was dying from AIDS. Russell was found two years later and returned to prison. Kemple died soon after.
教育行业基本上还未受到在线服务交付的影响——但可能会在2018年经历戏剧性的变化。
据Bryan Wang说,腾讯跟最近几年在海外特别是新兴市场销量越来越大的那些中国手机厂商达成了预装软件的协议,这给它提供了助力。
“欧洲工商管理学院极大地充实了我们的跨文化体验,”一位来自瑞士的校友在接受调查时表示,“在这里学习全球文化好于其他任何地方。”


n. 按揭,抵押贷款
n. 支柱,
But her success doesn't come cheap and her mother has already spent £5,000 on elaborate dresses and entry fees.


With the increasing proliferation and sophistication of mobile phones, wearable devices such as smart watches, and sensors that can measure and gather a variety of data, public interest is growing in using consumer electronics to take ownership of personal health and wellness. A 2015 survey found that 66% of Americans age 66 and older want to use mobile technologies to improve their health by receiving medication reminders and tracking diet and nutrition, physical activity, and symptoms.[1

“我们现在从中国看到的情况不仅仅是巴西一国的现象,我们在整个拉美都看到了同样的情况,中国对所有市场的出口都在下降,”负责马士基航运在巴西、巴拉圭、乌拉圭和阿根廷业务的执行董事安东尼奥?多明格斯(Antonio Dominguez)表示,“已经连续几个季度出现这种情况,但随着我们进入(2016)年,这种局面变得越来越明显了。”
目前,大部分围绕比特币的活动都是货币性的,因此,批评者指向其波动性也合乎情理。blockchain.info网站上的市场价格走势图显示,尽管以美元衡量的比特币价值在过去一年缩水了67%,其价值在过去两年则飙升了1879%。因此,投资比特币是好是坏,取决于你的视角。
《嘻哈帝国》(Empire),Fox,周三播出。这部最新的嘻哈乐肥皂剧的导演是电影人李·丹尼尔斯(Lee Daniels),他曾执导《珍爱》(Precious)和《白宫管家》(Lee Daniels’ The Butler))。片中泰伦斯·霍华德(Terrence Howard)饰演一个身患致命疾病的说唱乐大明星。
500个品牌来自28个不同国家,其中近半(227个)来自美国。

Health apps and wearables
Health apps and wearables can unobtrusively gauge physiological and emotional states and collect, quantify, and monitor data regarding a user’s day-to-day behaviors. This “quantified self” can increase users’ self-awareness regarding their behavior and encourage positive changes to their overall health and well-being.[2] These commercially available devices also integrate an array of features to provide motivation through reward systems, opportunities for social in-teraction, tools for self-improvement, and prompts. The novelty, affordability, practicality, and ease of use have resulted in increased consumer enthusiasm and the pervasiveness of these devices.[3,4] With this growing interest in personal health, members of the general public are becoming more involved in monitoring and improving their own health habits.[5-10

Undoubtedly, merely tracking data through a device is not enough to maintain good health-related behaviors long-term, and the software must also incorporate motivational constructs important for the adoption and habituation of behaviors. For instance, a systematic review of studies that considered the use of electronic activity monitor systems found short-term changes in physical activity with self-monitoring, but no demonstration of superiority when the systems were compared with other interventions.[11] Another review of studies on the viability of using mobile technology for measuring and influencing physical activity found that most apps allow users to document their activity, set goals, review real-time feedback, connect to a social support network, and access online expertise.[12] However, less common among these apps were prompts to act and opportunities for problem solving and action planning, which are crucial constructs that translate intention into long-term behavior change.[13]

Sensor technologies
Sensor technologies have begun to enter the telehealth landscape and are primarily focused on continuous monitoring and precise diagnostics to inform management of various health conditions and diseases.[14-17] Sensors can be integrated into a watch or arm band or adhesive bandages and clothing, and then programmed to collect data on cardiac rhythm, heart rate, blood pressure, respiration, oxygen saturation, galvanic skin response, glucose levels, body temperature, body motions, ambient temperature, and global positioning. For health care providers, sensor inputs can permit remote monitoring, real-time teleconferencing, and timely care for patients with chronic diseases. For both patients and clinicians, telehealth supported by sensors can have profound implications. Clinicians can provide timely and patient-centred care to those living at a distance with chronic disease and can coordinate care when multiple providers are involved, reducing costs to the health care system.

A current clinical example is the management of paroxysmal atrial fibrillation with a mobile ECG and app that monitors the patient’s electrical rhythm to detect frequency and patterns of arrhythmias, and may even allow patients to share ultrasound and electrocardiogram data with their health care provider.[18-20] Telemonitoring with sensors can also support self-management of chronic diseases and detect early signs of deterioration in health requiring immediate treatment and advice.[21] Studies to date have demonstrated some clinical promise for the use of home telemonitoring in the context of heart failure and diabetes. A recent Cochrane review found that telemonitoring was an effective way to lower levels of glycated hemoglobin and low-density lipoprotein.[22] Although several studies on heart failure have produced conflicting results regarding the overall benefits of home monitoring,[23-26] systematic reviews have suggested that home telemonitoring reduces all-cause mortality and hospitalizations, and improves quality of life compared with usual care.[22,27] In addition, features such as automated and mobile telemonitoring appear to be more effective compared with other forms of home telemonitoring.[27]

Further studies are needed to determine how home health monitoring can improve patient safety during the transition from acute care to community care, and to examine the impact of home monitoring on health care costs. TEC4Home (Telehealth for Emergency-Community Continuity of Care Connectivity via Home Tele-monitoring), an initiative of the University of British Columbia and Vancouver Coastal Health, is seeking to do this with prospective trials designed to uncover how telemonitoring can support the safety of heart failure patients discharged from hospital to home.[28]

Mobile apps, wearables, and sensors in the clinical setting
Even though mobile apps, wearables, and sensor technologies are promising, further research is needed to validate their use and long-term impact.[29] This research will require the collaboration of clinicians, health researchers, engineers, and computer scientists.[30] Understanding the possible risks of using these technologies, from physiological harm to breaching of privacy and confidentiality with insecure devices, and how to mitigate any risks is also important. Other important issues to consider include patient anxiety with overuse of technologies, health data piracy, self-diagnosis resulting from overreliance on self-monitoring, and patients not seeking help appropriately. These technologies should be used only as complementary tools in the treatment and prevention of health conditions and disease and should not be used in isolation by patients who self-diagnose and self-manage without consulting a health professional. 

n. 鼓励

Instant Heart Rate by Azumio.[31] A free app downloadable to both Apple and Android operating systems that measures heart rate and displays a monitoring strip. As well as helping users accurately track their heart rates, the app is capable of detecting irregular rhythms when palpitations occur. 

Sleep Time by Azumio.[32] A free app that monitors sleep patterns, sleep efficiency, and also acts as an alarm clock. Users can know how often they go into light and deep sleep, and recognize how much of these types of sleep will be necessary for them to feel rested, thereby quantifying the amount of true sleep they need and not just how long they should stay in bed. 

Bellybio Interactive Breating by RelaxLine.[33] A free app that helps users pace their breathing to achieve calmness. Placing the mobile phone against the abdomen, users can follow the sounds emitted to practise deep, abdominal breathing using this simple yet surprisingly effective tool. 

They boast two of the biggest fan bases in the world.But it was Shawn Mendes who reigned supreme during the 2017 Europe Music Awards 2017, held inside London's SSE Arena, Wembley, on Sunday night, as Taylor Swift lost out in all five of her categories.
GDP growth of around 6.5 percent, or higher if possible in practice.

本周二,年仅17岁的Thomas Sohmers推出了一个全新的高速计算机服务器,该计算机功耗极低,该计算机使用了低能耗的ARM处理器,而其所需电量仅为一台普通电脑一小部分。在本周在旧金山举行的Open Compute Project (OCP)大会上,Sohmers展示了这台服务器。这个产品是Sohmers所创办的企业REX所推出的第一个产品,REX的另一位创始人为52岁的Kurt Keville,目前Keville担任公司的CTO。
Other commentators, such as Raoul Leering, head of international trade analysis at ING, the Dutch financial group, fear the outlook is bleak even in the short term.
The wealth and depth of knowledge from around the world adds tremendous value to the course, wrote another graduate from the US, adding that “with so many cultures and experiences represented, a classroom ethics discussion about bribery is not your typical boring USA version”.
The unexpected drop in 2013 came in spite of new policies--such as the city's 72- hour visa waiver for transit passengers--that were introduced in an attempt to nurture China's tourism industry.
n. 行星
affected

Discernment to determine whether a particular app, wearable, or sensor can be effective.
Expertise and experience to guide patients on the use of technology.
Partnership with patients in pursuit of optimal health through technology use.
Trials to closely monitor benefits and drawbacks.
Humility to recognize that patients may know and invest much more time than physicians in looking for these tools.34

Conclusions
Based on today’s rapid pace of development and public enthusiasm for the technology marketplace, health apps, wearables, and sensors will soon become integral to our patients’ pursuits of good health and will need to be integrated in clinical practice. Physicians must be active agents in these evolutionary times, guiding patients, advocating for evidence to support the use of technologies, and participating in the development and incorporation of technology in patient wellness journeys. Through clinical stewardship and partnership with patients, physicians can use their expertise and experience to guide the growth of innovations into mainstream health care.

Competing interests
Dr Ho receives no personal financial compensation as the principal investigator of TEC4Home (Telehealth for Emergency-Community Continuity of Care Connectivity via Home Tele-monitoring), a project funded by a Canadian Institutes of Health Research grant. This grant is matched by the Michael Smith Foundation for Health Research and the BC Ministry of Health, with additional support provided by TELUS Health and Sentrian. TELUS Health, Cisco, and Avizia have also provided equipment for display in Dr Ho’s Demonstration and Simulation Studio for Health (DaSSH) at UBC. Mr Yao and Dr Lauscher have no competing interests to declare.


万科链家推新产品:号称要革装修界的命!


References

1. Cision PR Newswire. Fifth annual Pulse of Online Health survey finds 66% of Americans eager to leverage digital tools to manage personal health. Posted 24 February 2015. Accessed 28 August 2017. www.prnewswire.com/news-releases/fifth-annual-pulse-of-online-health-survey-finds-66-of-americans-eager-to-leverage-digital-tools-to-manage-personal-health-300039986.html.

2. Swan M. Emerging patient-driven health care models: An examination of health social networks, consumer personalized medicine and quantified self-tracking. Int J Environ Res Public Health 2009;6:492-525.

3. Gao Y, Li H, Luo Y. An empirical study of wearable technology acceptance in healthcare. Ind Manag Data Syst 2010;115:1704-1723.

4. Kim KJ, Shin DH. An acceptance model for smart watches: Implications for the adoption of future wearable technology. Internet Res 2015;25:527-541.

5. West JH, Hall PC, Hanson CL, et al. There’s an app for that: Content analysis of paid health and fitness apps. J Med Internet Res 2012;14:e72.

6. Abroms LC, Padmanabhan N, Thaweethai L, Phillips T. iPhone apps for smoking cessation: A content analysis. Am J Prev Med 2011;40:279-285.

7. Cowan LT, Van Wagenen SA, Brown BA, et al. Apps of steel: Are exercise apps providing consumers with realistic expectations? A content analysis of exercise apps for presence of behavior change theory. Health Educ Behav 2013;40:133-139.

8. Azar KM, Lesser LI, Laing BY, et al. Mobile applications for weight management. Am J Prev Med 2013;45:583-589.

9. Breland JY, Yeh VM, Yu J. Adherence to evidence-based guidelines among diabetes self-management apps. Transl Behav Med 2013;3:277-286.

10. Lyons EJ, Lewis ZH, Mayrsohn BG, Rowland JL. Behavior change techniques implemented in electronic lifestyle activity monitors: A systematic content analysis. J Med Internet Res 2014;16:e192.

11. Lewis ZH, Lyons EJ, Jarvis JM, Baillargeon J. Using an electronic activity monitor system as an intervention modality: A systematic review. BMC Public Health 2015;15:585.

12. Bort-Roig J, Gilson ND, Puig-Ribera A, et al. Measuring and influencing physical activity with smartphone technology: A systematic review. Sports Med 2014;44:671-686.

13. Rhodes RE, Yao CA. Models accounting for intention-behavior discordance in the physical activity domain: A user’s guide, content overview, and review of current evidence. Int J Behav Nutr Phys Act 2015;12:1-14.

14. Chen M, Gonzalez S, Vasilakos A, et al. Body area networks: A survey. Mob Networks Appl 2011;16:171-193.

15. Appelboom G, Camacho E, Abraham ME, et al. Smart wearable body sensors for patient self-assessment and monitoring. Arch Public Health 2014;72:28.

16. Chan M, Estève D, Fourniols JY, et al. Smart wearable systems: Current status and future challenges. Artif Intell Med 2012;56:137-156.

17. Alemdar H, Ersoy C. Wireless sensor networks for healthcare: A survey. Comput Networks 2010;54:2688-2710.

18. Haberman ZC, Jahn RT, Bose R, et al. Wireless smartphone ECG enables large-scale screening in diverse populations. J Cardiovasc Electrophysiol 2015;26:520-526.

19. Ferdman DJ, Liberman L, Silver ES. A smartphone application to diagnose the mechanism of pediatric supraventricular tachycardia. Pediatr Cardiol 2015;36:1452-1457.

20. Baquero GA, Banchs JE, Ahmed S, et al. Surface 12 lead electrocardiogram recordings using smart phone technology. J Electrocardiol 2015;48:1-7.

21. Wootton R. Twenty years of telemedicine in chronic disease management—An evidence synthesis. J Telemed Telecare 2012;18:211-220.

22. Flodgren G, Rachas A, Farmer A, et al. Interactive telemedicine: Effects on professional practice and health care outcomes. Cochrane Database System Rev 2015;(9):CD002098.

23. Mortara A, Pinna GD, Johnson P, et al. Home telemonitoring in heart failure patients: The HHH study (Home or Hospital in Heart Failure). Eur J Heart Fail 2009;11:312-318.

24. Dar O, Riley J, Chapman C, et al. A randomized trial of home telemonitoring in a typical elderly heart failure population in North West London: Results of the Home-HF study. Eur J Heart Fail 2009;11:319-325.

25. Chaudhry SI, Mattera JA, Curtis JP, et al. Telemonitoring in patients with heart failure. N Engl J Med 2010;363:2301-2309.

26. Koehler F, Winkler S, Schieber M, et al. Impact of remote telemedical management on mortality and hospitalizations in ambulatory patients with chronic heart failure: The Telemedical Interventional Monitoring in Heart Failure study. Circulation 2011;123:1873-1880.

27. Kitsiou S, Pare G, Jaana M. Effects of home telemonitoring interventions on patients with chronic heart failure: An overview of systematic reviews. J Med Internet Res 2015;17:e63.

28. TEC4Home Healthcare Innovation Community. Supporting heart failure patient transitions from acute to community care with home telemonitoring technology: A protocol for a provincial randomized controlled trial (TEC4Home). JMIR Res Protoc 2016;5:e198. 

29. Yao C, Ho K. Mobile sensors and wearable technologies. In: Amelung VE, Stein V, Goodwin N, et al., editors. Handbook integrated care. Cham, Switzerland: Springer; 2017.

30. Ho K, Borycki E, Kushniruk A, et al. The health perspective in using digital media for health and wellness. Presented at the IEEE International Digital Media Industry Forum, Boston, MA, 4-6 July 2016.

31. Azumio Inc. Instant heart rate. Accessed 28 August 2017. www.azumio.com/s/instantheartrate/index.html. 

32. Azumio Inc. Sleep time. Accessed 28 August 2017. www.azumio.com/s/sleeptime/index.html. 

33. RelaxLine. BellyBio. Accessed 28 August 2017. https://itunes.apple.com/ca/app/bellybio-interactive-breathing/id353763955?mt=8.

34. Ho K. How health information technologies are enhancing health of patients and their doctors. Presentation at the Alberta Medical Association 2015 Spring Representatives Forum, Edmonton, AB, 13 March 2015.


[k?ut?]
City on the Silk Road
In contrast, the nation witnessed a tumbling trend for minivans, whose volume totaled 71,300 units, a 31 percent drop year-on-year.
PwC has counted votes and provides winner envelopes for the Oscars and has done so for more than 80 years. This is the first time in Oscar history that the wrong envelope had been opened while an award was being announced.
第一架无线电操纵的无人驾驶飞机可追溯到1916年。英国发明家阿奇博尔德·洛设计并试飞了第一架无人遥控飞机。它是为了反攻德国齐柏林飞艇而制作的,在第一次世界大战中参与了对地面攻击的战斗。无人机由木和锡制成,它的机翼用的是其他双翼飞机的较低机翼。总的来说,无人机是有些失败的,因为它的引擎噪音干扰了无线操作。1916年,索普威斯飞松公司也尝试制作无人机,他们将无线电设备放置在无人机的尾部,这样引擎就不会干扰到它的信号。但因一次地面上的意外事故,他们的无人机再未起飞:当洛操作无人机飞到高级军官面前时,他原本计划会在1917年再次试飞无人机。但无人机从卡车的后面发射后,飞了一段时间便因引擎故障而坠毁,差点要了在场的军官的命。
“温总理的讲话重点提到了经济和社会发展。中国政府为实现建设繁荣社会这一目标付出了巨大的努力。”Irene Giner-Reichl, Austrian ambassador
Song “I Love You China”(Wang Feng)
n. 能力,容量,容积; 资格,职位
布朗克斯大广场区或皇后区埃尔姆赫斯特(Elmhurst)的业主们,即将迎来急于寻找下一个未开发市场的买家们的新关注。“你什么时候听到别人谈论过布朗克斯的金斯布里奇(Kingsbridge)?”霍尔斯特德房地产公司的拉米雷斯问,“聪明人正在涌向那里,以实惠的价格买下房子。”
With the majority of professional advisors (myself included) preaching the benefits of global diversification to their clients, 2014 looks more like a draw than an outright victory in the harsh light of December’s low winter sun. Consider the fact that, through last week, the MSCI World Index gained just 2% on the year, with nearly 5% drops for both the MSCI Emerging Markets index and the EAFE index of developed markets outside of the United States. Ironically, the single best-performing foreign market in the world, the Shanghai Composite of mainland Chinese equities (up 45%) is the only one that U.S. investors could not actually put their money into.

Kendall Ho, MD, FRCPC, Christopher Yao, MSc, Helen Novak Lauscher, PhD. Part 2: Health apps, wearables, and sensors: The advancing frontier of digital health. BCMJ, Vol. 59, No. 10, December, 2017, Page(s) 503-506 - Clinical Articles.



Above is the information needed to cite this article in your paper or presentation. The International Committee of Medical Journal Editors (ICMJE) recommends the following citation style, which is the now nearly universally accepted citation style for scientific papers:
Halpern SD, Ubel PA, Caplan AL, Marion DW, Palmer AM, Schiding JK, et al. Solid-organ transplantation in HIV-infected patients. N Engl J Med. 2002;347:284-7.

About the ICMJE and citation styles

The ICMJE is small group of editors of general medical journals who first met informally in Vancouver, British Columbia, in 1978 to establish guidelines for the format of manuscripts submitted to their journals. The group became known as the Vancouver Group. Its requirements for manuscripts, including formats for bibliographic references developed by the U.S. National Library of Medicine (NLM), were first published in 1979. The Vancouver Group expanded and evolved into the International Committee of Medical Journal Editors (ICMJE), which meets annually. The ICMJE created the 足球赛艇皮划艇帆船 to help authors and editors create and distribute accurate, clear, easily accessible reports of biomedical studies.

然而,一位要求匿名的律师表示,Teach First人从事教学工作获得的经验和自主能力可能意味着,他们会对再次从一家机构的底层做起感到沮丧。
新近成立的Eleven James正在男表领域引入合作消费的概念。该公司的会员项目能令你获得亲近一系列精挑细选的高端腕表的机会,这一曾经只和私人飞机、豪华汽车及度假屋联系在一起的会员模式正在Eleven James的手中发扬光大。除腕表外,会员还能注册专享忠诚度项目,其中包括礼宾服务、合伙人利益专享及诸如腕表主题活动等独一无二的体验。听起来有点像男士腕表和飞机租赁公司Net Jets体验的大碰撞?公司创始人兰迪?布兰多夫(Randy Brandoff)在奢侈品营销领域拥有深厚经验,曾经在Net Jets担任高级副总裁和首席营销官、在Marquis Jets担任过执行副总裁和首席营销官。他的专长,加上年复一年增长势头良好的腕表行业,以及一种在其他市场证明行之有效的商业模式——看起来Elven James正是在恰当的时间叩开了市场的大门。
Roles With Bite
据哈佛大学校报报道,至少10名学生因在脸书私聊小组中发布“猥琐表情”而失去哈佛大学的入学资格。

办事处副局长卢华东说:“自治区已投资40亿元人民币(约合6亿美元),用于推动贫困地区特色的产业,去年重新安置了77000名贫困人口。”

  • Only the first three authors are listed, followed by "et al."
  • 建材家居行业再度抢占“双11”榜单
  • “众筹”成为LED照明行业“跨界打劫”工具


她说:“人们不只是搜索有关球员和球队的信息,而是将其作为一次文化学习体验。这是首届在非洲举行的世界杯,人们想了解一下后种族隔离时代的南非。人们还想了解世界杯的声音制造者——呜呜祖拉。”
宾夕法尼亚州立大学的气候科学家迈克尔·E·曼恩(Michael E. Mann)在电子邮件中说,“如果不是由于燃烧化石燃料所产生的、导致地球变暖的气体排放越来越多的原因,在上千年史无前例的几十年较暖期间、创纪录地变暖的十年中,看到变暖的又一个记录年度,是非常不可能的。”

BCMJ Guidelines for Authors

Leave a Reply