Security and eavesdropping in terahertz wireless links.

Resiliency against eavesdropping and other security threats has become one of the key design considerations for communication systems. As wireless systems become ubiquitous, there is an increasing need for security protocols at all levels, including software (such as encryption), hardware (such as trusted platform modules) and the physical layer (such as wave-front engineering)1-5. With the inevitable shift to higher carrier frequencies, especially in the terahertz range (above 100 gigahertz), an important consideration is the decreased angular divergence (that is, the increased directionality) of transmitted signals, owing to the reduced effects of diffraction on waves with shorter wavelengths. In recent years, research on wireless devices6-8 and systems9-11 that operate at terahertz frequencies has ramped up markedly. These high-frequency, narrow-angle broadcasts present a more challenging environment for eavesdroppers compared to the wide-area broadcasts used at lower frequencies12,13. However, despite the widespread assumption of improved security for high-frequency wireless data links14-16, the possibility of terahertz eavesdropping has not yet been characterized. A few recent studies have considered the issue at lower frequencies5,12,13,17,18, but generally with the idea that the eavesdropper's antenna must be located within the broadcast sector of the transmitting antenna, leading to the conclusion that eavesdropping becomes essentially impossible when the transmitted signal has sufficiently high directionality15. Here we demonstrate that, contrary to this expectation, an eavesdropper can intercept signals in line-of-sight transmissions, even when they are transmitted at high frequencies with narrow beams. The eavesdropper's techniques are different from those for lower-frequency transmissions, as they involve placing an object in the path of the transmission to scatter radiation towards the eavesdropper. We also discuss one counter-measure for this eavesdropping technique, which involves characterizing the backscatter of the channel. We show that this counter-measure can be used to detect some, although not all, eavesdroppers. Our work highlights the importance of physical-layer security in terahertz wireless networks and the need for transceiver designs that incorporate new counter-measures.

How early warning with the Oxygen Reserve Index (ORi™) can improve the detection of desaturation during induction of general anesthesia?

The Oxygen Reserve Index (ORi™) is a dimensionless parameter with a value between 0 and 1. It is related to the real-time oxygenation status in the moderate hyperoxic range. The purpose of this study is to investigate the added warning time provided by different ORi alarm triggers and the continuous trends of ORi, SpO2, and PaO2. We enrolled 25 patients who were scheduled for elective surgery under general anesthesia with planned arterial catheterization before induction. The participants received standardized preoxygenation, induction, and intubation. The patients remained apneic and ventilation was resumed when the SpO2 fell below 90%. The ORi and SpO2 were recorded every ten seconds and arterial blood was sampled every minute, from preoxygenation to resumed ventilation. Alarm triggers set to the ORi peak and the ORi 0.55 values provided 300 and 145 s of significant added warning time compared to SpO2 (p < 0.0001). The coefficient of determination was 0.56 between the ORi and the PaO2 ≤ 240 mmHg and showed a positive correlation. The ORi enables the clinicians to monitor the patients' oxygen status during induction of general anesthesia and can improve the detection of impending desaturation. However, further studies are needed to assess its clinical potential in the high hyperoxic range.The protocol was retrospectively registered at ClinicalTrials.gov on July 21, 2021 (NCT04976504).

Synergic Effect of Robot-Assisted Rehabilitation and Antispasticity Therapy: A Narrative Review.

BACKGROUND: Stroke and spinal cord injury are neurological disorders that cause disability and exert tremendous social and economic effects. Robot-assisted training (RAT), which may reduce spasticity, is widely applied in neurorehabilitation. The combined effects of RAT and antispasticity therapies, such as botulinum toxin A injection therapy, on functional recovery remain unclear. This review evaluated the effects of combined therapy on functional recovery and spasticity reduction. MATERIALS AND METHODS: Studies evaluating the efficacy of RAT and antispasticity therapy in promoting functional recovery and reducing spasticity were systemically reviewed. Five randomized controlled trials (RCTs) were included. The modified Jadad scale was applied for quality assessment. Functional assessments, such as the Berg Balance Scale, were used to measure the primary outcome. Spasticity assessments, such as the modified Ashworth Scale, were used to measure the secondary outcome. RESULTS: Combined therapy improves functional recovery in the lower limbs but does not reduce spasticity in the upper or lower limbs. CONCLUSIONS: The evidence supports that combined therapy improves lower limb function but does not reduce spasticity. The considerable risk of bias among the included studies and the enrolled patients who did not receive interventions within the golden period of intervention are two major factors that should be considered when interpreting these results. Additional high-quality RCTs are required.

Effect of Platelet-Rich Plasma Augmentation on Endoscopy-Assisted Percutaneous Achilles Tendon Repair.

Background: Achilles tendon ruptures are one of the most common sports injuries. Recently, platelet-rich plasma (PRP) has been widely used in tendon-related disorders to enhance tendon healing. However, studies regarding PRP treatment in Achilles tendon rupture show inconsistent results. The purpose of this study was to evaluate the effectiveness of PRP in patients with acute Achilles tendon rupture treated with endoscopy-assisted percutaneous repair. Methods: A total of 62 patients with acute Achilles tendon rupture treated with surgical repair from January 2014 to December 2018 were enrolled in this study. Surgical repair in conjunction with PRP augmentation after surgery was classified as the PRP group. Surgical repair without PRP augmentation was classified as the non-PRP group. All patients were followed up at least 2 years post-operation. The outcomes were evaluated on the basis of rate of return to sports, time to return to play, Achilles Tendon Total Rupture Score (ATRS), calf circumference ratio, ankle range of motion (ROM) and complications following surgery. Results: At 2-year follow-up, the ATRS score was not significantly different between groups (p = 0.8), but the ATRS score in both groups improved with time. Rate of return to sports and time to return to play were not different between the two groups (p = 1.00). Moreover, calf circumference ratio and ankle ROM were evaluated at 6-month, 12-month, 18-month and 24-month follow-ups. At 6 months, the PRP group had better ankle ROM (p = 0.003) and a higher calf circumference ratio (p = 0.011); however, at the 24-month evaluation, there were no between-group differences regarding calf circumference ratio, ankle dorsiflexion and plantarflexion (p > 0.05). Conclusion: We show that PRP augmentation in Achilles tendon surgery did not yield superior functional and clinical outcomes. Therefore, clinicians should inform patients of the above information when undergoing Achilles tendon surgery and offer correct expectations to family and patients regrading PRP treatment.

The effect of medial calcar support on proximal humeral fractures treated with locking plates.

BACKGROUND: Studies have reported mixed results on the importance of medial calcar support for the treatment of proximal humeral fractures. The purpose of this study was to compare radiographic and functional outcomes of patients who had displaced proximal humeral fractures with varying levels of medial support. METHODS: We performed a retrospective comparative cohort study. The study was conducted at a Level III trauma center in Taiwan. Seventy patients with proximal humeral fractures were collected retrospectively from 2015 to 2019. Only patients with two-, three-, or four-part types (Neer type I, II, or III) of displaced proximal humeral fractures were included in this study. However, patients with head-split fracture patterns, shoulder dislocation, prior shoulder trauma, and poor fracture reduction present in postoperative films were excluded. We assessed the radiographic outcomes, including the reduction score and amount of impaction in the humeral head. The functional outcome was evaluated based on the Constant score. RESULTS: Patients were grouped into the intact medial calcar group and the medial calcar deficiency group. In a subgroup analysis, the group with intact medial support had a significantly lower amount of impaction and a higher Constant score compared with the medial calcar deficiency group. Additionally, the groups with intact medial support had a nonsignificant difference in the Constant score between the affected side and the contralateral side. CONCLUSION: The amount of impaction and the reduction score in the humeral head at the 12-month radiographic follow-up were significantly higher in the group with  medial support deficiency. However, the reduction score after surgery exhibited no difference. This implies that the inherent nature of medial comminution of proximal humeral fracture may lead to inferior radiographic outcomes.

Development and validation of a reference measurement procedure for certification of phenytoin, phenobarbital, lamotrigine, and topiramate in human serum using isotope-dilution liquid chromatography/tandem mass spectrometry.

Phenytoin (PHT), phenobarbital (PHB), lamotrigine (LTG), and topiramate (TPM) are some of the most widely used antiepileptic drugs (AEDs). Monitoring of their concentrations in serum is important for the treatment of epilepsy. A reference measurement procedure (RMP) for certification of PHT, PHB, LTG, and TPM in serum has been developed and critically evaluated. Isotopically labeled compounds of PHT, PHB, LTG, and TPM are used as internal standards for the four AEDs. The four drugs and their respective labeled internal standards are simultaneously extracted from serum using solid-phase extraction prior to reversed-phase liquid chromatography-tandem mass spectrometry (LC-MS/MS). Chromatographic separation was performed using a C(18) column. Electrospray ionization (ESI) in the positive ion mode for PHT and LTG, and in the negative ion mode for PHB and TPM were used. The recovery of AEDs added to serum (accuracy of the extraction method) was evaluated by recovery studies of measuring the four drugs in spiked samples with known drug levels. The recoveries of the added drugs ranged from 98.6% to 102.0%. The absolute recoveries (extraction efficiencies) of the four drugs with this method ranged from 97% to 100%. Excellent repeatability was obtained for the four drugs with between-set coefficients of variation (CVs) within 1%. The type B components estimates are conservatively large and are considerably larger than the type A component. Therefore, we use the usual metrological expansion factor of 2 to provide an approximate 95% coverage interval. The relative expanded uncertainties for the four AEDs ranged from 2.3% to 2.4%. This LC-MS/MS RMP for PHT, PHB, LTG, and TPM in serum demonstrating good accuracy and precision can be used to assess the accuracy of routine methods used in clinical laboratories.

Associations of Multimodal Analgesia With Postoperative Pain Trajectories and Morphine Consumption After Hepatic Cancer Surgery.

BACKGROUND: This study aimed to investigate the influential factors of postoperative pain trajectories and morphine consumption after hepatic cancer surgery with a particular interest in multimodal analgesia. METHODS: Patients receiving hepatic cancer surgery at a tertiary medical center were enrolled between 2011 and 2016. Postoperative pain scores and potentially influential factors like patient characteristics and the analgesic used were collected. Latent curve analysis was conducted to investigate predictors of postoperative pain trajectories and a linear regression model was used to explore factors associated with postoperative morphine consumption. RESULTS: 450 patients were collected, the daily pain scores during the first postoperative week ranged from 2.0 to 3.0 on average. Male and higher body weight were associated with more morphine consumption (both P < 0.001) but reduced morphine demand was noted in the elderly (P < 0.001) and standing acetaminophen users (P = 0.003). Longer anesthesia time was associated with higher baseline pain levels (P < 0.001). In contrast, male gender (P < 0.001) and standing non-steroidal anti-inflammatory drugs (NSAIDs) use (P = 0.012) were associated with faster pain resolution over time. CONCLUSIONS: Multimodal analgesia with standing acetaminophen and NSAIDs had benefits of opioid-sparing and faster pain resolution, respectively, to patients receiving hepatic cancer surgery.