greenteg-core-axillary

Core body temperature measures from a single subject with a non-24 circadian rhythm disorder, aged 33 years old at the start of measurements, weight between 72 and 77.5 kg.<br>The core body temperature measurements were done non-invasively with the GreenTEG CORE Research device, attached to the side of a Polar Pro chest strap band, placed on the axillary per the manufacturer's recommendations. The device captures core body temperature and skin temperature every second (1Hz sampling rate). It can store up to 3.5 days of data and takes 3h30 to 7h for data download, hence the gaps, which are placed during circadian daytime whenever possible. This device is able to measure the core body temperature using dual heat flux method (DHFM) with an in-house AI algorithm that replaces the standard DHFM equation to obtain more reliable readings according to the manufacturer. At the time of this experiment, this was the first and only wearable thermometer using heat flux technology.<br>The measurements are much more reliable since January 2021 so prefer to analyze the data from this date onwards. The device was changed in January 2021 for a new one because the old one broke due to a mechanical pressure flaw in the design. Since January 2021, an experimental attachment design using velcro sticked vertically on the CORE and with a loop around the Polar Pro band was conceived by the author/subject to avoid this mechanical flaw, and this had the unexpected side effect of improving significantly the reliability and extent of the surface of the CORE being in contact with the skin, so that measures are much more reliable and systematically reflect the circadian rhythm. Usually, the circadian night can be detected simply as being periods with a temperature below 36.5°C with this new attachment system.<br>Along with the sleep diaries, this is the most reliable circadian rhythm monitoring marker so far from preliminary results.<br>Note on data columns: most columns are encrypted gibberish data. Only the core body temperature, skin temperature flux 1, and timestamp are accessible and should be processed, the other columns can and should be discarded. More precisely, only the following columns are available (from the manufacturer's documentation):<br>* time [UTC-OFS=+0100] Timestamp of the data point in the format ‘DD:MM:YYYY hh:mm:ss’* timestamp [us] Timestamp in UNIX time in us (microseconds elapsed since January 1th 1970).* Hf_a0 Raw heat flux sensor signal of heat path A in ADC counts (unitless).* Temp_a0 [mC] Uncorrected temperature signal of heat path A in millidegree Celsius.* Cbt [mC] Core body temperature estimation output in millidegrees.<br><br>Note: Cbt needs to be divided by 1000 to get the core body temperature value in celsius degrees.<br>The following columns are not available and can be dropped as they are filled with random values: hf_a1, Temp_a1, ax, ay, az, Battery_voltage [mV].<br>Heat flux sensor A value can be obtained as follows:<br>Heat flux sensor A voltage [in uV] = hf_a0 [in counts] * 1.953125 uV<br><br>Skin temperature for sensor A can be obtained as follows:<br>Skin Temperature A [in °C] = (temp_a0 [in mC] – T0off) /1000<br><br>T0off is an offset that is defined once in the header of each CSV file.<br>There is a gap during January 2021, as this is the period the 1st device broke, before getting replaced by the manufacturer. The new dataset with the new device starts on 21th January 2021, with a new vertically oriented velcro attachment system devised by the author, which prevents the device from breaking and improves skin contact and hence data quality. It is recommended to analyze data after 21th January 2021 as it is likely the least noisy.<br>Each file represents one acquisition session of up to 3.5 days, hence they can be concatenated to study a longer time period.<br>Update: On 2021-05-29T21_25_00, the disposition of the velcro was changed from vertical to diagonal, so that the CORE device is oriented on skin as a losange instead of a square, which should further increase skin contact and data quality, since the chest strap now pushes on the two corners in the horizontal middle, with much less chances that it gets stuck in a local equilibrium at either of the vertical corners.<br>本数据集包含一名受试者的核心体温测量数据，该受试者患有非24小时昼夜节律紊乱（non-24 circadian rhythm disorder），测量开始时年龄为33岁，体重介于72至77.5千克之间。 核心体温测量采用非侵入式方式完成，使用GreenTEG CORE研究级设备（GreenTEG CORE Research device），该设备固定于Polar Pro胸带侧面，并按照制造商的建议佩戴于腋下。该设备每秒（采样率1Hz）采集核心体温与皮肤温度数据，可存储最长3.5天的测量数据，数据下载耗时3小时30分钟至7小时，因此存在数据间隙；此类间隙尽可能安排在昼夜节律的日间时段。该设备采用双热通量法（dual heat flux method，DHFM）进行核心体温测量，搭载自研AI算法替代标准DHFM公式，以获取更可靠的测量结果，据制造商称，本实验所用设备是全球首款且唯一一款采用热通量技术的可穿戴体温计。 自2021年1月起，测量数据的可靠性显著提升，因此建议优先分析该日期之后的数据。2021年1月，原设备因设计存在机械压力缺陷损坏，故更换为新设备。自2021年1月起，受试者本人设计了一种新型魔术贴（velcro）固定方案：将魔术贴垂直粘贴于CORE设备，并通过环带固定于Polar Pro胸带上，以规避此前的机械缺陷；该方案意外带来了额外收益：显著提升了设备与皮肤的接触可靠性与接触面积，使得测量结果更为可靠，且能够系统性地反映昼夜节律特征。借助该新型固定系统，通常可将昼夜节律的夜间时段直接识别为体温低于36.5℃的周期。 结合睡眠日记来看，本数据集是目前初步研究结果中可靠性最高的昼夜节律监测标志物之一。 关于数据列的说明：绝大多数列均为加密乱码数据，仅核心体温、热通量传感器1的皮肤温度与时间戳三类数据可正常读取并用于处理，其余列均可且应当丢弃。具体而言，根据制造商文档，仅以下列可用： * time [UTC-OFS=+0100]：数据点时间戳，格式为‘DD:MM:YYYY hh:mm:ss’，其时区为协调世界时偏移量+0100 * timestamp [us]：UNIX时间戳，单位为微秒（即自1970年1月1日00:00:00起经过的微秒数） * Hf_a0：热通路A的原始热通量传感器信号，以ADC计数为单位（无量纲） * Temp_a0 [mC]：热通路A的未校正温度信号，单位为毫摄氏度（mC） * Cbt [mC]：核心体温估算输出值，单位为毫摄氏度（mC） 注意：需将Cbt值除以1000，方可得到以摄氏度为单位的核心体温数值。 以下列无可用有效数据，均为随机填充值，可直接丢弃：hf_a1、Temp_a1、ax、ay、az、Battery_voltage [mV]。 热通量传感器A的电压（单位：微伏，uV）可通过以下公式计算： 热通量传感器A电压 [uV] = hf_a0 [计数] × 1.953125 uV 传感器A的皮肤温度可通过以下公式计算： 传感器A皮肤温度 [℃] = (temp_a0 [mC] – T0off) / 1000 其中T0off为偏移量，在每个逗号分隔值（CSV）文件的文件头中仅定义一次。 2021年1月存在数据间隙，该时段为原设备损坏至制造商更换新设备的过渡期。采用新设备的新数据集起始于2021年1月21日，搭配受试者设计的垂直魔术贴固定系统，该系统可防止设备损坏并优化皮肤接触效果，进而提升数据质量。建议优先分析2021年1月21日之后的数据，该时段的数据噪声水平最低。 每个文件代表一次最长3.5天的采集会话，因此可通过拼接多个文件以研究更长时间跨度的数据集。 更新说明：2021年5月29日21时25分00秒，魔术贴的固定方式由垂直调整为斜向，使得CORE设备在皮肤上的朝向由方形变为菱形；此举可进一步提升皮肤接触效果与数据质量，因为胸带现在会在水平中线的两个角施加压力，大幅降低了设备卡在垂直方向角落局部平衡状态的概率。