Unexpected Drop Research Articles

How Much Does Intravenous Fluid Cause Hematocrit to Drop? Improving Interpretation of Hematocrit Toward Better Post-Hemorrhage Care.

Hemorrhage is assessed, at least in part, via hematocrit testing. To differentiate unexpected drops in hematocrit because of ongoing hemorrhage versus expected drops as a result of known hemorrhage and intravenous fluid administration, we model expected post-operative hematocrit values accounting for fluid balance and intraoperative estimated blood loss (EBL) among patients without substantial post-operative bleeding. We reviewed patient-level data from the electronic health record of an academic medical center for all non-pregnant adults admitted for elective knee or hip arthroplasty from November 2013 to September 2022 who did not require blood products. We used linear regression to evaluate the association between post-operative hematocrit and predictor variables including pre-operative hematocrit, intraoperative net fluid intake, blood volume, time from surgery to lab testing, EBL, patient height, and patient weight. We included 6,648 cases. Mean (SD) estimated blood volume was 4,804 mL (1023), mean net fluid intake was 1,121 mL (792), and mean EBL was 144 mL (194). Each 100 mL of EBL and 1,000 mL net positive fluid intake was associated with a decrease of 0.52 units (95% CI, 0.51-0.53) and 2.4 units (2.2-2.7) in post-operative hematocrit. Pre-operative hematocrit was the strongest predictor of post-operative hematocrit. Each 1-unit increase in pre-operative hematocrit was associated with a 0.70-unit increase (95% CI, 0.67-0.73) in post-operative hematocrit. Our estimates were robust to sensitivity analyses, and all variables included in the model were statistically significant with P <.005. Patient-specific data, including fluid received since the time of initial hemorrhage, can aid in estimating expected post-hemorrhage hematocrit values, and thus in assessing for the ongoing hemorrhage.

Does pasteurization inactivate bird flu virus in milk?

ABSTRACT Recently, an outbreak of highly pathogenic avian influenza A (H5N1), which carries the clade 2.3.4.4b hemagglutinin (HA) gene and has been prevalent among North American bird populations since the winter of 2021, was reported in dairy cows in the United States. As of 24 May 2024, the virus has affected 63 dairy herds across nine states and has resulted in two human infections. The virus causes unusual symptoms in dairy cows, including an unexpected drop in milk production, and thick colostrum-like milk. Notably, The US Food and Drug Administration reported that around 20% of tested retail milk samples contained H5N1 viruses, with a higher percentage of positive results from regions with infected cattle herds. Data are scant regarding how effectively pasteurization inactivates the H5N1 virus in milk. Therefore, in this study, we evaluated the thermal stability of the H5 clade 2.3.4.4b viruses, along with one human H3N2 virus and other influenza subtype viruses, including H1, H3, H7, H9, and H10 subtype viruses. We also assessed the effectiveness of pasteurization in inactivating these viruses. We found that the avian H3 virus exhibits the highest thermal stability, whereas the H5N1 viruses that belong to clade 2.3.4.4b display moderate thermal stability. Importantly, our data provide direct evidence that the standard pasteurization methods used by dairy companies are effective in inactivating all tested subtypes of influenza viruses in raw milk. Our findings indicate that thermally pasteurized milk products do not pose a safety risk to consumers.

Non-monotonic plasticity and fracture in DP1000: Stress-state, strain-rate and temperature influence

Recent studies revealed a complex, non-monotonic relationship between flow stress, and temperature and strain rate for ultra-fine-grained DP1000 steel, including unexpected drops in ductility. Consequently, a comprehensive investigation into the interrelated effects of temperature, strain rate, and stress state on the plasticity and fracture behaviour of DP1000 steel is undertaken. To this purpose, eight purpose-designed specimen geometries, including a shear, a dogbone, a central hole, and various notched samples, are tested at strain rates covering 7 orders of magnitude from the quasi-static over the intermediate to the dynamic regime and in a temperature range from -40 to 400 °C. The experimental design thereby provides 336 unique combinations of stress state, strain rate and temperature. The study reveals phenomena typically associated with dynamic strain aging (DSA), such as flow stress serrations, negative strain rate sensitivity, thermal hardening, and embrittlement. As a result, the present study provides a comprehensive overview of the plastic, damage, and fracture behaviour of DP1000 steel. It also offers unique insights into the influence of external loading conditions on DSA. Increasing strain rates and decreasing temperatures suppressed DSA and its effects. However, a novel and important finding is that the impact of stress state on DSA and, consequently, on the behaviour of DP1000 steel cannot be solely explained by stress triaxiality and Lode angle. Lower stress triaxialities and Lode angle parameters amplify the occurrence and severity of DSA manifestations. However, non-proportional stress states, high-stress gradients and relatively low maximum in-plane shear stresses are also identified as contributing factors.

The role of inventory in firm resilience to the Covid-19 pandemic

We study the role of inventory in corporate financial management using the exogenous shocks to consumer demand, commodity prices, and global supply chains triggered by the COVID-19 pandemic. The sharp, unexpected drop in consumer demand and commodity prices increases the costs of holding inventory. On the flip side, inventory holdings provide a buffer against supply chain disruptions. Empirically, we find that U.S. firms with higher inventory levels experience a more negative stock market response to COVID-19. We identify the causal effects of inventory by controlling for unobserved firm heterogeneity, various firm characteristics, and endogeneity. The negative impact of inventory is more profound for firms with greater exposure to the slump in consumer demand and commodity prices. For firms that experience supply chain disruptions during COVID-19, inventory holdings have compensating effects. Financially constrained firms suffer higher costs of holding inventory during the crisis. We reconfirm that inventory carries significant costs during demand shocks using two other events – the 9/11 terrorist attacks and the global financial crisis.

Dam operation using satellite data and hydrological models: the case of Roseires dam and Grand Ethiopian Renaissance Dam in the Blue Nile River

ABSTRACT The unexpected drop of the Blue Nile water in July 2020, attributed to the sudden closure of the Grand Ethiopian Renaissance Dam (GERD) during the first filling in 2020, significantly interrupted the water supply for Khartoum, Sudan. This incident pursued using satellites and hydrological models to estimate inflows into Roseires dam. A hydrological model was developed to predict GERD inflows, while reservoir levels were extracted from Sentinel-1, -2 and Jason-3. A water balance model was developed to predict GERD releases and the dates of overtopping during subsequent fillings events. The study demonstrates the effectiveness of satellite data and models for transboundary reservoir management.

High-Accuracy Battery State of Charge Estimation Strategy Based on Deep Belief Network Cascaded With Extended Kalman Filter

Abstract Battery state of charge (SOC) estimation is one of the main functions of the battery management system in electric vehicles. If the actual SOC of the battery differs significantly from the estimated value, it can lead to improper battery usage, resulting in unexpected rapid voltage drops or increases, which can affect driving safety. Therefore, high-accuracy SOC estimation is of great importance for battery management and usage. Currently used SOC estimation methods suffer from issues such as strong dependence on model parameters, error propagation from measurements, and sensitivity to initial values. In this study, we propose a high-precision SOC estimation strategy based on deep belief network (DBN) feature extraction and extended Kalman filter (EKF) for smooth output. The proposed strategy has been rigorously tested under different temperature conditions using the dynamic stress test (DST) and urban dynamometer driving schedule (US06) driving cycles. The mean absolute error (MAE) and root-mean-square error (RMSE) of the proposed strategy are controlled within 1.1% and 1.2%, respectively. This demonstrates the high-precision estimation achieved. To further validate the generality of this strategy, we also apply it to graphene batteries and conduct tests under US06 and highway fuel economy test (HWFET) driving cycles at temperatures of 25 °C and −10 °C. The test results show MAE of 0.47% and 2.01%, respectively.

572 Pseudoaneurysm of Profunda Femoris Artery in a Patient Post Dynamic Hip Screw Fixation for a Neck of Femur Fracture: A Case Report

Abstract Background Profunda femoris artery (PFA) pseudoaneurysm as a complication of hip fracture is rare [1]. The majority of recorded cases of PFA pseudoaneurysm are caused by femur fractures, surgical operations, and penetrating trauma [2]. We present a case of PFA pseudoaneurysm following surgical fixation for neck of femur fracture with dynamic hip screw (DHS) and canulated cancellous screw. Case Presentation The patient sustained a fractured neck of femur fracture following a fall and was on long term antiplatelet therapy for ischaemic heart disease. Thery underwent surgical fixation with DHS and canulated cancellous screw but developed an unexpected drop in their haemoglobin post-op. Initial thigh ultrasound indicated a large, localised hematoma. Further investigation with CT angiography however demonstrated pseudoaneurysm of the branch of the profunda femoris artery. The patient was treated with coil embolization and was able to fully weight bear with support. Discussion Vascular injuries following hip fractures are becoming more common complications [2-4]. Pseudoaneurysms of the profunda femoris artery are an unusual but well-recognized consequence of proximal femoral fractures. When post-operative pain is unexplained, or the haemoglobin level drops, there should be a high index of suspicion for vascular injury. Ultrasound and CT angiography are useful investigations. Conclusions We present a case of pseudoaneurysm of the PFA in a patient following DHS for fractured neck of femur. This is a rare yet recognised complication of femur fractures and should be suspected where pain is increased or there is a sudden decrease in haemoglobin.

An Efficient Detection Framework for Aerial Imagery Based on Uniform Slicing Window

Drone object detection faces numerous challenges such as dense clusters with overlapping, scale diversity, and long-tail distributions. Utilizing tiling inference through uniform sliding window is an effective way of enlarging tiny objects and meanwhile efficient for real-world applications. However, merely partitioning input images may result in heavy truncation and an unexpected performance drop in large objects. Therefore, in this work, we strive to develop an improved tiling detection framework with both competitive performance and high efficiency. First, we formulate the tiling inference and training pipeline with a mixed data strategy. To avoid truncation and handle objects at all scales, we simultaneously perform global detection on the original image and local detection on corresponding sub-patches, employing appropriate patch settings. Correspondingly, the training data includes both original images and the patches generated by random online anchor-cropping, which can ensure the effectiveness of patches and enrich the image scenarios. Furthermore, a scale filtering mechanism is applied to assign objects at diverse scales to global and local detection tasks to keep the scale invariance of a detector and obtain optimal fused predictions. As most of the additional operations are performed in parallel, the tiling inference remains highly efficient. Additionally, we devise two augmentations customized for tiling detection to effectively increase valid annotations, which can generate more challenging drone scenarios and simulate the practical cluster with overlapping, especially for rare categories. Comprehensive experiments on both public drone benchmarks and our customized real-world images demonstrate that, in comparison to other drone detection frameworks, the proposed tiling framework can significantly improve the performance of general detectors in drone scenarios with lower additional computational costs.

Age-Related Differences in Kinematics, Kinetics, and Muscle Synergy Patterns Following a Sudden Gait Perturbation: Changes in Movement Strategies and Implications for Fall Prevention Rehabilitation

Falls in older adults are leading causes of fatal and non-fatal injuries, negatively impacting quality of life among those in this demographic. Most elderly falls occur due to unrecoverable limb collapse during balance control in the single-limb support (SLS) phase. To understand why older adults are more susceptible to falls than younger adults, we investigated age-related differences in lower limb kinematics, kinetics, and muscle synergy patterns during SLS, as well as their relationship to postural control strategies. Thirteen older and thirteen younger healthy adults were compared during the SLS phase of balance recovery following an unexpected surface drop perturbation. Compared to younger adults, older adults demonstrated (1) greater trunk flexion, (2) increased hip extension torque and reduced hip abduction torque of the perturbed leg, and (3) higher postural sway. Trunk flexion was correlated with a delayed latency to the start of lateral-to-medial displacement of center of mass from the perturbation onset. The group-specific muscle synergy revealed that older adults exhibited prominent activation of the hip extensors, while younger adults showed prominent activation of the hip abductors. These findings provide insights into targeted balance rehabilitation and indicate ways to improve postural stability and reduce falls in older adults.

The Degradation in Creep Strength of ASME Grade 122 Steel

The degradation of the long-term rupture strength of ASME Grade 122 steel occurs earlier than that of Grade 92 steel. To investigate the reasons for this phenomenon, the long-term creep curves of Grade 122 steel pipe, plate, and tube product forms were analyzed by applying an exponential law to the temperature, stress, and time parameters. The activation energy (Q), activation volume (V), and Larson&amp;ndash;Miller constant (C) were obtained as functions of creep strain. All Q, V, and C&amp;nbsp;(QVC) decreased simultaneously with an increase in creep strain during the transient creep in a data group (Gr.IIIa), where an unexpected drop in the long-term rupture strength was experienced. Metallurgical considerations of the variations in QVC&amp;nbsp;meant that &amp;ldquo;heterogeneous recovery and heterogeneous deformation&amp;rdquo; (HRHD) should occur during the simultaneous decreases in QVC. The Z-phase is easily formed by the consumption of the strengthening particles of MX in the HRHD zone, which causes the degradation of the long-term strength of Grade 122 steel. The higher hardness of Grade 122 steels promotes the coarsening of the Laves phase particles and, in addition to this, the amount of MX inside the subgrains is estimated to be less than Grade 92 steel, which cause severe HRHD and the resultant degradation in rupture strength compared to Grade 92 steel. In a data group subjected to lower stresses than those of Gr.IIIa, the degradation rate is mitigated, and a deformation mechanism was proposed. The improvement in the long-term rupture strength of Grade 122 steel was also discussed.

Life history and population dynamics of the enigmatic tanaid Chondrochelia dubia (Tanaidacea: Leptocheliidae) in a tropical seaweed bed

The present study describes the population dynamics and life history parameters of the enigmatic tanaid Chondrochelia dubia collected in Paiva Beach, tropical coast of Brazil. The region was impacted by a large, unexpected oil spill from August to October 2019. Samples were taken monthly between July 2019 and July 2020 in beds of the red seaweed Jania capillacea. The abundance of individuals was negatively correlated with monthly rainfall, with higher abundances in drier months. There was an unexpected significant drop in abundance in September, possibly caused by contact with the crude oil, but the population recovered fully within two months. The parameters of the von Bertallanfy growth equation, calculated for the first time for the species, were Linf=5.26 mm; k=3.36 year–1; t0=0.0. Compared with other studies, the specimens are very small (2.04 ± 0.95 mm in length), females reach sexual maturity very early (L50=2.3 mm), and natural mortality is high (Z=M=5.77 year–1), indicating an opportunistic life strategy. This study reinforces the bioindication potential of C. dubia and the use of bootstrapped length-based methods to estimate key population parameters in small marine invertebrates.

Development and Optimization of a Highly Sensitive Sensor to Quinine-Based Saltiness Enhancement Effect

The saltiness enhancement effect can be produced by adding specific substances to dietary salt (sodium chloride). This effect has been used in salt-reduced food to help people forge healthy eating habits. Therefore, it is necessary to objectively evaluate the saltiness of food based on this effect. In a previous study, sensor electrodes based on lipid/polymer membrane with Na+ ionophore have been proposed to quantify the saltiness enhanced by branched-chain amino acids (BCAAs), citric acid, and tartaric acid. In this study, we developed a new saltiness sensor with the lipid/polymer membrane to quantify the saltiness enhancement effect of quinine by replacing a lipid that caused an unexpected initial drop in the previous study with another new lipid. As a result, the concentrations of lipid and ionophore were optimized to produce an expected response. Logarithmic responses have been found on both NaCl samples and quinine-added NaCl samples. The findings indicate the usage of lipid/polymer membranes on novel taste sensors to evaluate the saltiness enhancement effect accurately.

МОДЕЛЬ ОЦІНКИ МАТЕМАТИЧНОГО СПОДІВАННЯ ШВИДКОСТІ ВИТРАТИ ПАЛЬНОГО ПІДРОЗДІЛОМ ЗБРОЙНИХ СИЛ УКРАЇНИ

The study of the experience of conducting an anti-terrorist operation (ATO) and an operation of the United Forces (OUF) in the war against the Russian Federation allows us to conclude that today the use of modern means of fire damage in combination with new approaches to intelligence conducting has had a significant effect on increasing the intensity and speed of troops movement during hostilities. In such conditions, random (unforeseen) consumption of fuel may appear with a simultaneous sudden decrease in its reserves below the specified (acceptable) norms. An unexpected drop in fuel reserves in military equipment can be related to many factors and, as a result, create conditions that will not allow to perform tasks in the offensive, during the development of success and when solving other combat tasks in the next day of hostilities. In order to ensure the fulfillment of combat missions by units and subunits of the Armed Forces and to prevent the limitation of their combat capability in connection with an unforeseen shortage of fuel during the operation, there is a need to develop a mathematical model, the use of which in the future will allow to calculate the time after which the level of fuel reserves will decrease below the permissible norm, and in the dynamics of the work of the logistics headquarters, it contributes to the timely provision of the troops needs. In the article, for the first time, simple expressions were obtained for calculating the required sample volume of a random fuel consumption value in the UAF subunits and for the error of estimating the mathematical expectation of this value in the sample, which guarantees the fulfillment of the requirements for the accuracy of calculations with a sample size significantly smaller than the traditional one and without using the concepts of "confidence interval" and "confidence probability", and corresponds to the limited capabilities of the Ukraine Armed Forces subunits to collect statistics during hostilities. The developed model can be used for further development of mathematical tools for predicting possible fuel consumption, for predicting needs and for providing the troops with fuel up to the established standards in a timely manner.

Effect of addition of polymerized polymethyl methacrylate (PMMA) and zirconia particles on impact strength, surface hardness, and roughness of heat cure PMMA

Introduction: This study was designed to examine the effects of addition of the combination of polymerized polymethyl methacrylate (PMMA) and zirconia (ZrO2) particles to heat cure PMMA resin on impact strength, surface hardness, and roughness. Methods: The 70% (w/w) of polymerized PMMA powder (particle size: 0.70 µm) was mixed with 30% (w/w) of zirconia powder (ZrO2) (1 µm) to produce PMMA-ZrO2 filler. Ninety acrylic specimens created were divided into three groups containing 0% wt (Control group), 2% wt, and 4% wt, PMMA-ZrO2 filler. Ten specimens were used for impact strength, surface hardness and roughness test, blindly. Data were analyzed via one-way ANOVA and the Tukey post hoc test using R 3.6.3. Results: There was statistically significant difference among study groups regarding surface hardness and roughness (p &lt; 0.001). Yet, nonsignificant difference was found on the subject of impact strength (p = 0.33). Post hoc test showed statistically significant difference for all pairwise comparisons as regards surface hardness and roughness (p &lt; 0.05). Conclusion: The incorporation of PMMA-ZrO2 filler did not improve impact strength (resistance during an unexpected blows or dropping). Yet, increased surface roughness and hardness, concentration-dependently.

Contribution of Lower Limb Eccentric Control to Balance Recovery From Surface Drop Perturbations

<h3>Research Objectives</h3> To investigate age-related differences in eccentric neuromuscular control of the knee and its relationship to postural stability during balance recovery following unexpected surface drop perturbations. <h3>Design</h3> Cross sectional, comparative study. <h3>Setting</h3> General community. <h3>Participants</h3> Healthy, community dwelling, and ambulatory older (n=10, age=75.3±5.6) and younger (n=10, age=25.7±2.0) adults. <h3>Interventions</h3> N/A. <h3>Main Outcome Measures</h3> 1) Eccentric knee extension work (J/kg); 2) EMG burst duration (s) in the perturbed leg during the single limb support phase of compensatory stepping; 3) postural sway (standard deviation of center of mass acceleration, m/s2) in the anterior-posterior (A-P), medio-lateral (M-L), vertical directions; 4) margin of stability (MoS) of first compensatory step touchdown after perturbations. <h3>Results</h3> Following an 8 cm surface drop perturbation at gait initiation, older adults (OA) compared to younger adults (YA), demonstrated reduced eccentric knee extensor work (OA: 0.013±0.005 J/kg, YA: 0.020±0.007 J/kg, p=0.034), rectus femoris EMG burst duration (OA: 0.35±0.07s, YA: 0.47±0.08s, p< 0.01), MoS (OA: 68.41±14.30%, YA: 82.88±13.24%, p=0.04), and increased postural sway in all directions (A-P: OA: 2.29±1.38m/s2, YA: 1.03±0.54 m/s2, p=0.02, M-L: OA: 1.42±0.71 m/s2,YA: 0.72±0.41m/s2, p=0.02, Vertical: OA: 4.17±1.01m/s2, YA: 1.74±0.86m/s2, p< 0.01). There was a negative correlation between eccentric work and postural sway in the M-L direction (r = -0.54, p=0.012) and a positive correlation between eccentric work and MoS (r = +0.55, p=0.009). <h3>Conclusions</h3> This study is the first to demonstrate that age-related differences in eccentric control of the perturbed leg are associated with maintaining postural stability and improving compensatory stepping balance response following unexpected surface drop perturbations. Older adults demonstrated deficits in eccentric knee extensor control and this contributed to greater postural sway and unstable compensatory stepping during balance recovery. This finding provides insight into mechanisms of fall recovery and directions for lower limb strengthening exercises for aging populations. Future investigations of these mechanisms in aging populations with a disability due to neurological or musculoskeletal impairments such as Parkinson's disease, stroke, and osteoarthritis are warranted. <h3>Author(s) Disclosures</h3> The contents of this abstract were developed under a grant from NIDILRR (90AR5028).

Age-related differences in stepping stability following a sudden gait perturbation are associated with lower limb eccentric control of the perturbed limb.

Falls are a leading cause of severe injuries and a major threat to quality of life in older adults. Elderly fallers demonstrate insufficient eccentric quadriceps control during the weight acceptance phase of initial single limb stance. However, the functional role of eccentric control of the perturbed (leading) leg during walking balance recovery and its age-related differences have not yet been studied; thus we investigated age-related differences in eccentric control at the knee of the perturbed leg and its influence on the postural sway and stability of the trailing leg during balance recovery following unexpected surface drop perturbations. Ten younger and ten older healthy adults were compared during balance recovery following an 8cm unexpected surface drop perturbation at gait initiation. Outcomes related to perturbed leg included 1) eccentric knee extensor work; 2) electromyography (EMG) peak amplitude, peak latency, and eccentric EMG burst duration of the rectus femoris (RF); and 3) knee flexion angle during the single limb support. Outcomes related to stability of the trailing leg included 4) margin of stability (MoS) at first compensatory step touchdown after the perturbation. 5) Postural sway (standard deviation of center of mass acceleration) was measured in the anterior-posterior (A-P), medio-lateral (M-L), vertical directions during the single limb support. Compared to younger adults, older adults demonstrated lower eccentric knee extensor work (p=0.034), shorter RF EMG burst duration (p<0.01), delayed RF EMG peak latency (p=0.01), smaller knee flexion angle (p=0.01) and MoS (p=0.04), and higher postural sway (M-L (p=0.02), vertical (p<0.01)). There was a positive correlation between eccentric work and MoS (p=0.03) and a negative correlation between M-L postural sway and 1) RF eccentric EMG burst duration (p=0.04), and 2) eccentric work (p=0.01). Older adults demonstrated deficits in eccentric knee extensor control in the perturbed leg during single limb support, which contributed to reduced stability of the trailing leg compensatory step and greater postural sway during balance recovery. This finding provides insight into mechanisms of fall recovery from an unexpected unilateral postural perturbation and directions for lower limb strengthening exercises for aging populations.

Real Time Safety Assessment Based on Hira for Portable and Overhanging Lifting Machine- Construction Site

Cranes are an essential machine for many industries. Due to the fact that it is so large, and it moves such heavy gadget, it can also be very dangerous. Most cranes manage to move at the base in order to put the load where it needs to go. When this occurs, anyone who is in the area surrounding the crane could get trapped in a pinch point and get crushed. The crane driver typically does not have visibility to the area directly on every side the machine, which produces this safety hazard even more serious. Unfortunately, when large numbers of cranes have been dispatched to a Industrial site, the hazard exposure also increases for workers who work with, around or under these cranes. As per OSHA, 85% of all cranes unsettle and structural failures can be allocate to exceeding the crane’s operational capacity. When a crane is overloaded, it is subject to structural stresses that may cause irreparable damage. Swinging or unexpected dropping of the load, using defective components, hoisting a load far away capacity, pull a load, and side-loading a boom can all cause overloading. The only way to eliminate the accidents is Identify the Hazards to assess the associated controls with the Material Lifting machinery with their operations to bring the hazard to tolerable level. As the part of this dissertation hazard recognition will carried out with the help of checklist and different mathematical methodology with respect to various lifting machines and their control measures will also be given in this work, improved safe work conditions in industry for using this engineering tool this is the objective of this project work and to reduce the number of accidents. The main objective of this study was to examine the various hazards associated with using cranes will help of checklist to identify the risks in the workplace.

Motor block and hypotension following a high thoracic erector spinae plane block.

Dear Editor, Erector spinae plane blocks (ESPBs) are becoming more prevalent in clinical practice for postoperative pain control following truncal procedures. ESPBs are often quoted as being easy to perform and having few complications. We describe a patient with a thoracic epidural spread after administering an ultrasound-guided unilateral high thoracic ESPB for a video-assisted thoracoscopic procedure (VATS). A 62-year-old woman with chronic smoking, hypertension, and asthma was scheduled for an elective right VATS upper lobectomy for a malignant lesion. Her body weight was 78 kg, and she had no functional limitations. After obtaining informed consent, standard Canadian Anesthesia Society monitors were applied. She received preprocedural 1 mg of intravenous midazolam. The block was performed in the block room by an anesthesia resident under an experienced attending anesthesiologist’s supervision. In a sitting position, right ESB was performed using a linear ultrasound transducer oriented in the parasagittal plane. An out-of-plane approach was used due to the shorter needling distance, thus mitigating discomfort. After contacting the T4 TP, 20 ml of 0.5% ropivacaine was injected, and a local anesthetic was seen spreading deep to the erector spinae muscle. She was transferred to the operating room following an uneventful 10 min of monitoring in the block room. Upon directing the patient to move from the stretcher to the operating table, she noted having decreased bilateral lower limb sensation and motor weakness. Physical exam revealed decreased strength in hip flexion and a bilateral truncal sensory from T4 to L4 dermatomes. Her blood pressure had dropped to 73/36. She did not have any shortness of breath, chest pain, or light headedness. An awake radial arterial line was placed, and a phenylephrine infusion was initiated at 20 mcg/min. With her blood pressure stabilized, the decision was made to proceed with surgery. With surgical stimulation, she was able to wean off the phenylephrine infusion. She had no motor weakness or sensory loss following an uncomplicated 3 h long VATS lobectomy. In the post-anesthetic care unit (PACU), Pain scores were between 4 and 6, and blood pressure was 99/66. In a review, the incidence of complications of ESPBs is 0.2%, including bilateral lower limb weakness, motor block, transient apathy, aphasia, dizziness, loss of consciousness due to systemic toxicity and pneumothorax.[1] Selvi et al.[2] reported an unexpected motor weakness following bilateral T11 ESPB, and De Cassai et al.[3] reported near-complete lower extremity immobility following bilateral L3 ESPB for lumbar laminectomy. Our patient experienced bilateral motor and sensory block along with significant hypotension 15 min after a high unilateral thoracic ESPB. Given the symmetrical nature of the blockade and its resolution, we postulated that the local anesthetic injected had spread to the epidural space via the costotransverse foramen.[3] This may be related to the orientation and the angulation of the needle. Such a precipitous and unexpected drop in blood pressure could result in hemodynamic instability and cardiac compromise in some patients. Although seemingly rare, caution must be taken. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Detection rate dependence of the inherent detection efficiency in single-photon detectors based on avalanche diodes

Single-photon detectors are a pivotal component in photonic quantum technologies. A precise and comprehensive calibration of the inherent detection efficiency is of utmost importance to ensure the proper evaluation of the performance in view of the specific technological application of interest, such as the protection against security breaches in quantum cryptographic solutions. Here we report on a systematic study and comprehensive analysis of the estimation of the inherent detection efficiency of two commercial single-photon detectors based on single-photon avalanche diodes for various mean photon numbers and at high laser pulse repetition rates using different techniques. We observe an unexpected and significant drop in the inherent detection efficiency at detection rates of 10% and higher relative to the maximum detection rate. It is demonstrated that for data analysis a statistical model for the detection rate conveniently can be used if no time-stamped data are available. We conclude that the full characterization of single-photon detectors used in critical applications should include the sensitivity of their inherent detection efficiency to high event rates.

Experimental investigation on bond behaviours of deformed steel bars embedded in early age concrete under biaxial lateral pressures at low curing temperatures

The unexpected temperature drop during the concrete curing process could degrade the concrete properties at early age, and then decrease the bond behaviour between concrete and reinforcing steel bars. To assess the effect of low curing temperature on structural safety, it is significantly important to investigate the bond behaviour of early age concrete under such extreme environmental conditions. In this study, pull-out tests were conducted on the early-age concrete specimens with embedded deformed steel bars at the low curing temperature of 0 °C and the normal temperature of 20 °C. All specimens were subjected to biaxial lateral pressures varying from 0.1 fcu to 0.4 fcu to investigate the effect of simultaneous confining pressure. The results indicated that comparing with the specimens cured at 20 °C, the bond strength for the specimens cured at 0 °C decreased significantly at earlier ages of 3 and 7 days. However, the bond strength increased steadily with the increase of the curing age. Eventually, the concrete specimens at the 28-day age reached the same bond strength for both low and normal curing temperatures. In addition, the average slip displacements corresponding to the bond strengths for the specimens at the low curing temperature was slightly lower than those at the normal curing temperature. Based on the experimental results, an empirical model of bond stress-slip relationship was proposed for the early age concrete at low curing temperatures. Comparing with other existing models, the proposed bond stress-slip relationship agreed well with the experimental results, validating its applicability for the early age concrete at low curing temperatures.