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Spinal loads are recognized to play a causative role in back disorders and pain. Knowledge of lumbar spinal loads is required in proper management of various spinal disorders, effective risk prevention and assessment in the workplace, sports and rehabilitation, realistic testing of spinal implants as well as adequate loading in in vitro studies. During the last few decades, researchers have used a number of techniques to estimate spinal loads by measuring in vivo changes in the intradiscal pressure, body height, or forces and moments transmitted via instrumented vertebral implants. In parallel, computational models have been employed to estimate muscle forces and spinal loads under various static and dynamic conditions. Noteworthy is the increasing growth in latter computational investigations. This paper aims to review, compare and critically evaluate the existing literature on in vivo measurements and computational model studies of lumbar spinal loads to lay the foundation for future biomechanical studies. Towards this goal, the paper reviews in separate sections models dealing with static postures (standing, sitting, lying) as well as slow and fast dynamic activities (lifting, sudden perturbations and vibrations). The findings are helpful in many areas such as work place safety design and ergonomics, injury prevention, performance enhancement, implant design and rehabilitation management.

Mechanical characteristics of both the healthy ascending aorta and acute type A aortic dissection were investigated using in vitro biaxial tensile tests, in vivo measurements via transoesophageal echocardiography and histological characterisations. This combination of analysis at tissular, structural and microstructural levels highlighted the following: (i) a linear mechanical response for the dissected intimomedial flap and, conversely, nonlinear behaviour for both healthy and dissected ascending aorta; all showed anisotropy; (ii) a stiffer mechanical response in the longitudinal than in the circumferential direction for the healthy ascending aorta, consistent with the histological quantification of collagen and elastin fibre density; (iii) a link between dissection and ascending aorta stiffening, as revealed by biaxial tensile tests. This result was corroborated by in vivo measurements with stiffness index, β, and Peterson modulus, Ep, higher for patients with dissection than for control patients. It was consistent with histological analysis on dissected samples showing elastin fibre dislocations, reduced elastin density and increased collagen density. To our knowledge, this is the first study to report biaxial tensile tests on the dissected intimomedial flap and in vivo stiffness measurements of acute type A dissection in humans.

Raman spectroscopy has been demonstrated as a viable technique for non-invasive glucose monitoring (NIGM). However, its clinical utility is limited by an extended calibration period lasting several weeks. In this study, we address this limitation by employing a pre-trained calibration model, which is individualized through a brief calibration phase consisting of 10 measurements. The performance of the Raman-based NIGM device was evaluated in a clinical trial involving 50 individuals with type 2 diabetes over a 2-day study period. The protocol included a 4-h calibration phase on the first day, followed by validation phases of 4 h and 8 h on days 1 and 2, respectively. NIGM glucose readings were compared with capillary blood glucose measurements, with glucose fluctuations induced by standardized meal challenges. The numerical and clinical accuracy of the NIGM device was evaluated on 1918 paired points and expressed by mean absolute relative difference of 12.8% (95% CI 12.4, 13.2) and consensus error grid analysis showing 100% of NIGM readings in zones A and B. These results highlight the ability to reliably track blood glucose levels in people with type 2 diabetes. The successful introduction of a practical calibration scheme underlines Raman spectroscopy as a promising technology for NIGM and constitutes an important step towards factory calibration.

Reliable and timely assessment of bone union between vertebrae is considered a key challenge after spinal fusion surgery. Recently, a novel sensor concept demonstrated the ability to objectively assess posterolateral fusion based on continuous implant load monitoring. The aim of this study was to investigate systematically the concept in a mono-segmental fusion model using an updated sensor setup. Three sheep underwent bilateral facetectomy at level L2-L3 and L4-L5. The segments were stabilized using two unconnected pedicle-screw-rod constructs per level. Sensing devices were attached to the rods between each pedicle screw pair and the loads were continuously monitored over 16 weeks. After euthanasia, the spines were biomechanically tested for their range of motion and high-resolution CT scans were performed to confirm the fusion success. After an initial increase in implant load until reaching a maximum (100 %) at approximately week 4, eleven out of twelve sensors measured a constant decrease in implant load to 52 ± 9 % at euthanasia. One sensor measurement was compromised by newly forming bone growing against the sensor clamp. Bridging bone at each facet and minor remnant segmental motion (<0.7°) confirmed the fusion of all motion segments. Data obtained by continuous measurement of implant loading of spinal screw-rod constructs enables objective monitoring of spinal fusion progression. The sensor concept provides valuable real-time information, offering quantifiable data as an alternative to traditional imaging techniques. However, the design of the current sensor concept needs to be matured, tailored to, and validated for the human spine.

Blood flow simulations are making their way into the clinic, and much attention is given to estimation of fractional flow reserve in coronary arteries. Intracardiac blood flow simulations also show promising results, and here the flow field is expected to depend on the pulmonary venous (PV) flow rates. In the absence of in vivo measurements, the distribution of the flow from the individual PVs is often unknown and typically assumed. Here, we performed intracardiac blood flow simulations based on time-resolved computed tomography on three patients, and investigated the effect of the distribution of PV flow rate on the flow field in the left atrium and ventricle. A design-of-experiment approach was used, where PV flow rates were varied in a systematic manner. In total 20 different simulations were performed per patient, and compared to in vivo 4D flow MRI measurements. Results were quantified by kinetic energy, mitral valve velocity profiles and root-mean-square errors of velocity. While large differences in atrial flow were found for varying PV inflow distributions, the effect on ventricular flow was negligible, due to a regularizing effect by mitral valve. Equal flow rate through all PVs most closely resembled in vivo measurements and is recommended in the absence of a priori knowledge.

Undiagnosed type 2 diabetes (T2D) remains a major public health concern. The global estimation of undiagnosed diabetes is about 46%, being this situation more critical in developing countries. Therefore, we proposed a non-invasive method to quantify glycated hemoglobin (HbA1c) and glucose in vivo. We developed a technique based on Raman spectroscopy, RReliefF as a feature selection method, and regression based on feed-forward artificial neural networks (FFNN). The spectra were obtained from the forearm, wrist, and index finger of 46 individuals. The use of FFNN allowed us to achieve an error in the predictive model of 0.69% for HbA1c and 30.12 mg/dL for glucose. Patients were classified according to HbA1c values into three categories: healthy, prediabetes, and T2D. The proposed method obtained a specificity and sensitivity of 87.50% and 80.77%, respectively. This work demonstrates the benefit of using artificial neural networks and feature selection techniques to enhance Raman spectra processing to determine glycated hemoglobin and glucose in patients with undiagnosed T2D.

•Dermestes tessellatocollis is a forensically important insect for PMI estimation.•Development of D. tessellatocollis was monitored from 16 to 34 °C.•Development models were constructed which can be used to estimate PMImin.•Developmental threshold temperature and thermal constant were obtained.•Instar determination accuracy was unsatisfactory for application in casework. Dermestidae generally appears on dry corpses and carcasses, especially if mummified or skeletonized. They are forensically important insect species for estimating longer postmortem intervals (PMI). As they develop, Dermestidae larvae undergo multiple larval ecdyses; however, a lack of guidelines for determining the larval instar limits their forensic application. Herein, we explored how temperature impacts the development of Dermestes tessellatocollis Motschulsky, 1860 (Coleoptera: Dermestidae). At seven constant temperatures (16, 19, 22, 25, 28, 31, and 34 °C), the developmental time from egg to adult was 163.87 ± 9.19, 103.56 ± 3.02, 63.59 ± 2.88, 51.49 ± 2.74, 47.86 ± 3.01, 44.62 ± 4.65, and 41.80 ± 4.87 days respectively. Four morphological indexes, including head capsule width, pronotum width, mesonotum width, and body length, were taken in vivo at regular intervals to identify methods for larval instar determination in D. tessellatocollis. The acquired morphological data were used to simulate fitted curves and equations depicting the relationship between the four morphological indexes and instars. From the validation experiment, we could hardly determine a specific instar based on the morphological indexes. The combination of morphometric data (head capsule, pronotum, and mesonotum width) generated the classification accuracy at 100%, 87.5%, 85%, and 93% for the 1st, 2nd/3rd, 4th/5th, and 6th/7th instars, respectively. Nevertheless, the accuracy was unsatisfactory for application in forensic casework. This study provides fundamental development data for adopting D. tessellatocollis in minimum postmortem interval (PMImin) estimations; however, further studies are needed to improve the classification accuracy for the larval instar determination.

Senescence seems to be universal in living organisms and plays a major role in life‐history strategies. Phenotypic senescence, the decline of body condition and/or performance with age, is a largely understudied component of senescence in natural insect populations, although it would be important to understand how and why insects age under natural conditions. We aimed (i) to investigate how body mass and thorax width change with age in a natural population of the univoltine Clouded Apollo butterfly (Parnassius mnemosyne, Lepidoptera: Papilionidae) and (ii) to assess the relationship of this change with sex and wing length. We studied a population between 2014 and 2020 using mark‐recapture during the whole flight period each year. Repeated measurements of body mass and thorax width and single measurements of wing length were performed on marked individuals. We analyzed body mass and thorax width change with age (days since marking), wing length, and the date of the first capture. Both body mass and thorax width declined nonlinearly with age. Individuals appearing earlier in the flight period had significantly higher initial body mass and thorax width and their body mass declined faster than later ones. Initial body sizes of females were higher, but males' body sizes decreased slower. Initial thorax width showed higher annual variation than body mass. To our best knowledge, this is the first study that revealed phenotypic senescence in a natural butterfly population, using in vivo measurements. We found sexual differences in the rate of phenotypic senescence. Despite the annual variation of initial body sizes, the rate of senescence did not vary considerably across the years. Phenotypic senescence is a largely understudied component of senescence in natural insect populations. In a wild Clouded Apollo population investigated by us, both body mass and thorax width declined nonlinearly with age. Individuals appearing earlier in the flight period had significantly higher initial body mass and thorax width, and their body mass declined faster than later ones. Initial body sizes of females were higher, but males' body sizes decreased slower. Initial thorax width showed higher annual variation than body mass.

Background/Objectives: Laser Doppler flowmetry enables rapid and simple measurement of microcirculation. However, variations in probe configuration can influence signal acquisition, making it essential to understand each probe’s characteristics when selecting equipment for specific physiological assessments. Therefore, this study aimed to compare perfusion measurements obtained with single-fiber (VP1T) and multi-fiber (VP1T/7) probes and to evaluate the effects of normalization strategies. Methods: Nine healthy female volunteers were recruited. Probes were positioned on the palmar aspects of the index and middle fingers of both hands while participants underwent a standardized brachial artery occlusion protocol. Data are presented as mean ± standard error of the mean. Correlations were assessed using Pearson’s correlation coefficient. Coefficients of variation (CV) and intraclass correlation coefficients were calculated. Baseline normalization was applied to measurements. Statistical analyses were performed using Student’s t-test, with significance set at p < 0.05. Results: Analysis of the full protocol revealed significant positive correlations between probes, indicating consistent temporal perfusion patterns. The VP1T/7 probe yielded significantly higher perfusion values than the VP1T probe, although both exhibited similar CVs. Inter-probe reliability was good, and intra-probe reproducibility ranged from good to excellent, particularly for the VP1T/7 probe. During the reperfusion phase, significant differences were observed only for ipsilateral measurements obtained with the VP1T probe. Normalization effectively reduced variability, and significant differences during reperfusion were detected with both probes. Conclusions: Although the multi-fiber probe consistently recorded higher perfusion values, normalization was essential to reduce variability and to enhance the detection of microvascular reactivity parameters.

Purpose Robotic-assisted surgery has been recently introduced to improve biomechanical restoration, and thus better clinical and functional outcomes, after knee joint arthroplasty operations. Robotic-assisted uni-compartmental knee arthroplasty (UKA) aims indeed to improve surgical bone resection and alignment accuracy, optimized component positioning and knee balancing, relying on a series of calibration measurements performed during the surgery. These advantages focus therefore on improving the reproducibility of UKA surgeries, reducing (if not eliminating) eventual differences among high- and low-volume surgeons. The purpose of this study is to investigate and quantify the reproducibility of in-vivo measurements performed with a robotic system: the intra- and inter-observer variability of a series of measurements was therefore analyzed and compared among differently experienced operators. Methods Five patients were analyzed and underwent robotic-assisted UKA using a semi-active robotic system. Three different observers with different experience levels were involved to independently perform the measurements of two parameters of the preoperative knee (Hip-Knee-Ankle angle [HKAa], Internal-External Rotation) at different degrees of knee flexion. Inter-observer and intra-observer comparisons were performed. Results The average variability in the measurements obtained from the intra-observer and inter-observer comparisons were always < 0.68° for HKAa and < 2.59° for internal-external rotation, and the ICCs showed excellent agreement (> 0.75) for most cases and good agreement (> 0.60) in the remaining ones. Conclusion This study demonstrated high reproducibility of the measurements obtainable in clinical environment with the robotic system. The inter-observer results furthermore showed that the level of confidence with the robotic system is not significantly influencing the measurement.