Energy and exergy assessment of heavy-duty mining trucks. Discussion of saving opportunities.

Heavy-duty mining trucks are essential for open-pit mining and are significant energy consumers, stressing the need for the mining industry to improve the fuel economy of mining trucks. However, there is a limited discussion on this topic in the specialized literature, mainly focusing on light-duty vehicles. This article discusses the energy and exergy balances of heavy-duty mining trucks operating in an open pit mine in Colombia. Results show saving opportunities by either using batteries or producing hydrogen with the power from regenerative brakes, reducing heat losses in the engine, recovering heat losses with combustion gases using thermoelectric generators, and replacing mechanical pumps with electrical pumps. The assessment shows that reducing engine heat losses by coating the cylinder, cylinder head, and piston crown can reduce fuel consumption between 1.8 % and 9.1 %. Moreover, the production of hydrogen, while economically feasible, needs to assess the implementation of electrolyzers in mining trucks. Other measures are not economically viable. Using batteries, which requires adding 12 t of weight to the truck, reduces truck productivity. Finally, using thermoelectric generators and replacing mechanical pumps shows marginal opportunities to reduce fuel consumption.

Mecánica Tusígena / Cough Mechanics

El control neurológico de la tos o la neurofisiología de la tos, implica una serie de eventos complejos en el sistema nervioso que coordinan y desencadenan este reflejo protector pulmonar. Esta intrincada red de señales nerviosas y coordinación muscular se origina en los receptores de la tos, pasa por el centro de la tos en el bulbo raquídeo y finalmente activa los músculos necesarios para la adecuada eliminación del agente irritante. Este mecanismo involucra, la detección del estímulo por receptores especializados, transducción de señales que viajan a lo largo de fibras nerviosas aferentes hacia el sistema nervioso central, centro integrador a nivel del bulbo raquídeo, en el centro de la tos es donde se procesa las señales de los receptores y se coordina la respuesta. La integración de las señales y la respuesta radica en este centro de la tos y en la corteza cerebral quien regula y modula la tos. El control neuronal cortical de la tos implica la participación consciente y voluntaria de la corteza cerebral en la percepción, regulación y adaptación de la tos. La coordinación muscular requiere que la señal viaje por vías nerviosas eferentes motoras hacia los músculos involucrados, la contracción muscular se integra en una secuencia específica que desencadena las fases de la tos, inspiración máxima, compresión y expulsiva.

The neurological control of cough, or the neurophysiology of cough, involves a series of complex events in the nervous system that coordinate and trigger this lung protective reflex. This intricate network of nerve signals and muscle coordination originates from the cough receptors, passes through the cough center in the medulla oblongata, and finally activates the muscles necessary for proper elimination of the irritant. This mechanism involves the detection of the stimulus by specialized receptors, transduction of signals that travel along afferent nerve fibers towards the central nervous system, integrating center at the level of the medulla oblongata, in the cough center is where the signals are processed. receptors and the response is coordinated. The integration of signals and response resides in this cough center and in the cerebral cortex, which regulates and modulates coughing. Cortical neural control of cough involves the conscious and voluntary participation of the cerebral cortex in the perception, regulation, and adaptation of cough. Muscle coordination requires that the signal travel through efferent motor nerve pathways to the muscles involved; muscle contraction is integrated into a specific sequence that triggers the cough, maximum inspiration, compression, and expulsive phases.

Characterization of muscle mass, strength and mobility of critically ill patients with SARS-CoV-2 pneumonia: Distribution by sex, age, days on mechanical ventilation, and muscle weakness.

Objective: Quantify and categorize by sex, age, and time spent on mechanical ventilation (MV), the decline in skeletal muscle mass, strength and mobility in critically ill patients infected with SARS-CoV-2 and requiring mechanical ventilation while at intensive care unit (ICU). Design: Prospective observational study including participants recruited between June 2020 and February 2021 at Hospital Clínico Herminda Martin (HCHM), Chillán, Chile. The thickness of the quadriceps muscle was evaluated by ultrasonography (US) at intensive care unit admission and awakening. Muscle strength and mobility were assessed, respectively, through the Medical Research Council Sum Score (MRC-SS) and the Functional Status Score for the Intensive Care Unit Scale (FSS-ICU) both at awakening and at ICU discharge. Results were categorized by sex (female or male), age (<60 years old or ≥60 years old) and time spent on MV (≤10 days or >10 days). Setting: Intensive care unit in a public hospital. Participants: 132 participants aged 18 years old or above (women n = 49, 60 ± 13 years; men n = 85, 59 ± 12 years) admitted to intensive care unit with a confirmed diagnosis of severe SARS-CoV-2 and requiring MV for more than 48 h were included in the study. Patients with previous physical and or cognitive disorders were excluded. Interventions: Not applicable. Results: Muscle thickness have significantly decreased during intensive care unit stay, vastus intermedius (-11%; p = 0.025), rectus femoris (-20%; p < 0.001) and total quadriceps (-16%; p < 0.001). Muscle strength and mobility were improved at intensive care unit discharge when compared with measurements at awakening in intensive care unit (time effect, p < 0.001). Patients ≥60 years old or on MV for >10 days presented greater muscle loss, alongside with lower muscle strength and mobility. Conclusion: Critically ill patients infected with SARS-CoV-2 and requiring MV presented decreased muscle mass, strength, and mobility during their intensive care unit stay. Factors associated with muscle mass, such as age >60 years and >10 days of MV, exacerbated the critical condition and impaired recovery.

Intraoperative Hypotension Is Not Correlated With Acute Kidney Injury During Spinal Fusion Surgery.

BACKGROUND: Intraoperative hypotension (IOH) has been found to be associated with organ damage, including cardiac injury and acute kidney injury (AKI). However, to our knowledge, this relationship has not been studied in a neurosurgery-specific patient population. In this report, we review our institutional experience to understand the magnitude of association between IOH in spinal fusion operations and incidence of postoperative AKI. METHODS: This retrospective cohort study included 910 patients who underwent posterior spinal fusion procedures performed in the prone position. Intraoperative variables collected and analyzed include minute-by-minute mean arterial pressure (MAP) from an arterial catheter, intermittent blood pressure cuff readings, volume of administered intravenous fluids, urine output, and all relevant vitals and administered medications. The electronic medical record was queried for additional patient data. IOH was defined as MAP <65 mm Hg for greater than 10 minutes. The primary endpoints of the study were presence and staging of AKI ( [Kidney Disease: Improving Global Outcomes] consensus classification), postoperative ileus, and postoperative troponin leak. RESULTS: Using a partial correlation analysis, no association was found between IOH metrics (IOH occurrence, IOH duration >10 minutes, and total IOH time) and any outcome metrics, including AKI, except for vasopressor usage and estimated blood loss. Patient age at surgery was not associated with any outcome variables. The lack of association between IOH and AKI contrasts with existing literature; this could be due to underlying differences in our patient population or could highlight a more complex relationship between IOH and AKI than previously understood. CONCLUSION: Occurrence and duration of IOH were not associated with AKI, postoperative ileus, troponin leak, length of stay, or any other major outcome variables in spinal fusion patients. CLINICAL RELEVANCE: These findings depart from previous literature showing a correlation between IOH and AKI and provide level 3 evidence clinically relevant to spinal surgery. Further research is needed to better understand the exact nature of this relationship.

Application of a TEG-Platelet Mapping Algorithm to Guide Reversal of Antiplatelet Agents in Adults with Mild-to-Moderate Traumatic Brain Injury: An Observational Pilot Study.

BACKGROUND: Traumatic intracranial hemorrhages expand in one third of cases, and antiplatelet medications may exacerbate hematoma expansion. However, the reversal of an antiplatelet effect with platelet transfusion has been associated with harm. We sought to determine whether a thromboelastography platelet mapping (TEG-PM)-guided algorithm could limit platelet transfusion in patients with hemorrhagic traumatic brain injury (TBI) prescribed antiplatelet medications without a resultant clinically significant increase in hemorrhage volume, late hemostatic treatments, or delayed operative intervention. METHODS: A total of 175 consecutive patients with TBI were admitted to our university-affiliated, level I trauma center between March 2016 and December 2019: 54 preintervention patients (control) and 121 patients with TEG-PM (study). After exclusion for anticoagulant administration, availability of neuroimaging and emergent neurosurgery, 62 study patients and 37 control patients remained. Intervention consisted of administration of desmopressin (DDAVP) for nonsurgical patients with significant inhibition at the arachidonic acid or adenosine diphosphate receptor sites. For surgical patients with significant inhibition, dual therapy with DDAVP and platelet transfusion was employed. Study patients were compared with a group of historical controls, which were identified from a prospectively maintained registry and typically treated with empiric platelet transfusion. RESULTS: Median age was 75 years (interquartile range 85-67) and 77 years (interquartile range 81-65) in the TEG-PM and control patient groups, respectively. Admission hemorrhage volumes were similar (10.7 cm3 [20.1] in patients with TEG-PM vs. 14.1 cm3 [19.7] in controls; p = 0.41). There were no significant differences in admission Glasgow Coma Scale, mechanism of trauma, or baseline comorbidities. A total of 57% of controls versus 10% of patients with TEG-PM (p < 0.001) were transfused platelets; 52% of intervention patients and 0% controls were treated with DDAVP. Expansion hemorrhage volumes were not significantly different (14.0 cm3 [20.2] patients with TEG-PM versus 13.6 cm3 [23.7] controls; p = 0.93). There was no significant difference in rates of clinical deterioration, delayed neurosurgical intervention, or late platelet transfusion between groups. CONCLUSIONS: Among patients with hemorrhagic TBI prescribed preinjury antiplatelet therapy, our study suggests that the use of a TEG-PM algorithm may reduce platelet transfusions without a concurrent increase in clinically significant hematoma expansion. Further study is required to prove a causative relationship.

Effectiveness of Oral Antibiotic Therapy in Prevention of Postoperative Wound Infection Requiring Surgical Washout In Spine Surgery.

BACKGROUND: Surgical site infections (SSIs) after spine surgery are a significant cause of morbidity. Surgeons often prescribe oral antibiotics in the postoperative setting for infected-appearing wounds to prevent reoperation for infection; however, the efficacy of this practice has not been well studied. METHODS: Neurosurgical spine patients with clinical concerns for SSI at the University of Pennsylvania were retrospectively studied from 2014 to 2018. Clinical predictors of 90-day reoperation for infection despite antibiotic treatment and variables that influenced antibiotic prescription were analyzed. RESULTS: Three hundred and ninety-two patients were included in the study. Preoperative albumin level, days elapsed to antibiotic prescription from index surgery, preoperative hemoglobin level, surgical location, gender, discharge disposition, and level of wound concern were significant predictors of reoperation for infection on bivariate analysis. Days elapsed to antibiotic prescription, surgical location, and level of wound concern remained significant after multivariable logistic regression. Variables that significantly predicted prescription of an antibiotic include length of stay, cerebrospinal fluid leak, race, and level of wound concern. Length of stay, race, and level of wound concern remained significant after multivariable analysis. CONCLUSIONS: Wound infection remains a challenging problem in spine surgery and it is reasonable to perform early reoperation in patients with high clinical concerns for infection, because bacterial isolates are often resistant to common oral antibiotics. Patients with wounds with low clinical concerns for infection may undergo a trial of oral antibiotics; however, duration of treatment should not be prolonged.

Resecting the dominant lesion: Patient outcomes after surgery and radiosurgery vs stand-alone radiosurgery in the setting of multiple brain metastases.

BACKGROUND: Brain metastases are the most common central nervous system (CNS) tumors, occurring in 300,000 people per year in the US. While there are immediate local benefits to surgical resection for dominant lesions, including reduction of tumor burden and edema, the survival benefits of surgical resection, over radiosurgery, remains unclear. METHODS: The University of Pennsylvania Health System database was retrospectively reviewed for patients presenting with multiple brain metastases from 1/1/16-8/31/18 with one dominant lesion > 2 cm in diameter, who underwent initial treatment with either resection of the dominant lesion or Gamma Knife radiosurgery (GKS). Inclusion criteria were age > 18, > 1 brain metastasis, and presence of a dominant lesion (>2 cm). We analyzed factors associated with mortality. RESULTS: 129 patients were identified (surgery=84, GKS=45). The median number of intracranial metastases was 3 (IQR: 2-5). The median diameter of the largest lesion was 31 mm (IQR: 25-38) in the surgery group vs 21 mm (IQR: 20-24) in the GKS group (p < 0.001). Mortality did not differ between surgery and GKS patients (69.1% vs 77.8%, p = 0.292). In a multivariate survival analysis, there was no difference in mortality between the surgery and GKS cohorts (aHR: 1.35, 95% CI: 0.74-2.45 p = 0.32). Pre-operative KPS (aHR: 0.97, 95% CI: 0.95-0.99, p = 0.004), CNS radiotherapy (aHR: 0.33, 95% CI: 0.19-0.56 p < 0.001), chemotherapy (aHR: 0.27, 95% CI: 0.15-0.47, p < 0.001), and immunotherapy (aHR: 0.41, 95% CI: 0.25-0.68, p = 0.001) were associated with decreased mortality. CONCLUSION: In our institution, patients with multiple brain metastases and one symptomatic dominant lesion demonstrated similar survival after GKS when compared with up-front surgical resection of the dominant lesion.

Evaluating a Muscle Ultrasound Education Program: Theoretical Knowledge, Hands-on Skills, Reliability, and Satisfaction of Critical Care Physiotherapists.

OBJECTIVE: To evaluate learning results of critical care physiotherapists participating in a muscle ultrasound (MUS) educational program. DESIGN: Cross-sectional study. SETTING: A custom-made 20-hour MUS course was performed over a 2-week time period, including knobs familiarization, patient positioning, anatomic landmarks, image acquisition, and limb muscle measurements. PARTICIPANTS: Nineteen critical care physiotherapists with little to no prior experience in ultrasound (N=19). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Theoretical knowledge, hands-on skills acquisition, and satisfaction were assessed. Inter- and intrarater reliability on landmarks, thickness, and pennation angle of quadriceps between participants was evaluated using intraclass correlation coefficients (ICCs). Reliability among instructors measured prior to the course was also reported as a reference. RESULTS: The percentage score (mean±SD) of knowledge questionnaires was 69±11 (pre-course), 89±10 (post-course), and 92±9 (hands-on skills). Course satisfaction scores ranged from 90%-100%. Pooled interrater reliability of participants (median ICC [interquartile range]) was good (0.70 [0.59-0.79]) for thickness, moderate (0.47 [0.46-0.92]) for landmarks, and absent (0.00 [0.00-0.05]) for pennation angle and the intrarater reliability was good (0.76 [0.51-0.91]) for thickness and weak (0.35 [0.29-0.52]) for pennation angle. Interrater ICC values for instructors were excellent (0.90) for thickness, good (0.67) for landmarks, and moderate (0.41) for pennation angle and intrarater ICC values were excellent (0.94) for thickness and good (0.75) for pennation angle. CONCLUSIONS: Although our sample was quite small and homogeneous, increased theoretical knowledge, high hands-on performance acquisition, and good satisfaction of physiotherapists were observed. Reliability was moderate to excellent for thickness and landmarks and absent to weak for pennation angle. Landmarking and pennation angle remain challenges for physiotherapist training in the application of MUS. Further studies are needed to identify variables that could modify reliability during MUS training.

Neural Crest-Like Stem Cell Transcriptome Analysis Identifies LPAR1 in Melanoma Progression and Therapy Resistance.

Metastatic melanoma is challenging to clinically address. Although standard-of-care targeted therapy has high response rates in patients with BRAF-mutant melanoma, therapy relapse occurs in most cases. Intrinsically resistant melanoma cells drive therapy resistance and display molecular and biologic properties akin to neural crest-like stem cells (NCLSC) including high invasiveness, plasticity, and self-renewal capacity. The shared transcriptional programs and vulnerabilities between NCLSCs and cancer cells remains poorly understood. Here, we identify a developmental LPAR1-axis critical for NCLSC viability and melanoma cell survival. LPAR1 activity increased during progression and following acquisition of therapeutic resistance. Notably, genetic inhibition of LPAR1 potentiated BRAFi ± MEKi efficacy and ablated melanoma migration and invasion. Our data define LPAR1 as a new therapeutic target in melanoma and highlights the promise of dissecting stem cell-like pathways hijacked by tumor cells. SIGNIFICANCE: This study identifies an LPAR1-axis critical for melanoma invasion and intrinsic/acquired therapy resistance.

Tumor-infiltrating mast cells are associated with resistance to anti-PD-1 therapy.

Anti-PD-1 therapy is used as a front-line treatment for many cancers, but mechanistic insight into this therapy resistance is still lacking. Here we generate a humanized (Hu)-mouse melanoma model by injecting fetal liver-derived CD34+ cells and implanting autologous thymus in immune-deficient NOD-scid IL2Rγnull (NSG) mice. Reconstituted Hu-mice are challenged with HLA-matched melanomas and treated with anti-PD-1, which results in restricted tumor growth but not complete regression. Tumor RNA-seq, multiplexed imaging and immunohistology staining show high expression of chemokines, as well as recruitment of FOXP3+ Treg and mast cells, in selective tumor regions. Reduced HLA-class I expression and CD8+/Granz B+ T cells homeostasis are observed in tumor regions where FOXP3+ Treg and mast cells co-localize, with such features associated with resistance to anti-PD-1 treatment. Combining anti-PD-1 with sunitinib or imatinib results in the depletion of mast cells and complete regression of tumors. Our results thus implicate mast cell depletion for improving the efficacy of anti-PD-1 therapy.

Surgical Management of Trauma-Related Intracranial Hemorrhage-a Review.

PURPOSE OF REVIEW: The surgical management of trauma-related intracranial hemorrhage is characterized by marked heterogeneity. Large prospective randomized trials have generally been prohibited by the ubiquity of concordant pathology, diversity of trauma systems, and paucity of clinical equipoise among providers. RECENT FINDINGS: To date, the results of retrospective studies and surgeon preference have driven the indications, modality, extent, and timing of surgical intervention in the global neurosurgical community. With advances in our understanding of the pathophysiology of hemorrhagic TBI and the advent of novel surgical techniques, a reevaluation of surgical indication, timing, and approach is warranted. In this way, we can work to optimize surgical outcomes, achieving maximal functional recovery while minimizing surgical morbidity.

Data to support the assessment of the energy efficiency estimation methods on induction motors considering real-time monitoring.

The data presented in this article was used to assess and compare the most important methods used to estimate the efficiency during the operation of induction motors at different loads and power supply conditions. The experiment was developed in a test bench including a three-phase induction motor of 1.1 kW (De Lorenzo DL 1021). In addition, an adjustable voltage source, a variable-frequency drive, a resistor, and a magnetic powder brake control unit to regulate the load were used during the experiments. A power quality and energy analyzer (Fluke 435 series 6) was used to measure the electric variables during the experiments. Moreover, for the mechanical measures, the sensors of the brake control unit (De Lorenzo DL 1054TT) and a magnetic powder brake (De Lorenzo DL 1019P) were used. In total, 11 load factors were measured at different operation conditions, including balanced sinusoidal voltage, balanced harmonic voltage, unbalanced sinusoidal voltage and unbalanced harmonic voltage. A total of 10 measures were taken for each load factor at each operation condition. The data presented in this paper can be useful in the development and evaluation of new efficiency estimation methods for induction motors, considering different operation conditions and load factors. Moreover, it can serve to assess the impact of the energy quality on the efficiency of induction motors. The data is related to the manuscript "Assessment of the energy efficiency estimation methods on induction motors considering real-time monitoring" [1].

Data supporting the evaluation of the energy recovery potential of thermoelectric generators in diesel engines.

Power generation with thermoelectric devices in internal combustion engines is an alternative to recover some of the energy loss with the exhausts. This data article supports a study that assesses the potentialities of energy recovery with thermoelectric generators in diesel engines and its influence on gaseous emissions. To this end, a set of experiments was developed with a thermoelectric generator and a waffle heat exchanger. The experimental design included nine operation points of the engine to characterize the energy recovery of the thermoelectric generator under different exploitation conditions. Three different fuels (i.e., diesel, B5, and B10) were used. The experiments were developed in a test bench with three data acquisition systems to measure the operational variables (e.g., electric power generation, pressure drop, temperature, etc.). Moreover, a gas analyzer (BrainBee AGS-688), Bacharach gas analyzer (PCA 400), and a smoke meter (BrainBee OPA-100) were used to measure exhaust emissions.

Penetrating Spinal Column Injuries (pSI): An Institutional Experience with 100 Consecutive Cases in an Urban Trauma Center.

BACKGROUND: Gunshot wound (GSW) injuries are among the leading causes of penetrating spinal column injury (pSI). Patients with pSI often have concurrent polytrauma that complicates management. METHODS: We retrospectively reviewed charts between January 2012 to June 2018 at an urban Level 1 trauma center and analyzed bracing and surgical indications, antibiotic and magnetic resonance imaging (MRI) use, and patient outcomes. RESULTS: We identified 100 patients with pSI with an average age of 27.2 (range, 15-58) years. Five patients had knife injuries and 95 suffered GSW. Polytrauma occurred in 90% of patients with an average of 3.39 bullets per patient (range, 1-23). Fourteen patients underwent either decompressive surgery (n = 8) or decompression and fusion (n = 6). Thirty-five patients were externally braced. A total of 43% of patients presented as American Spinal Injury Association-A compared with 26% who were intact. Although 14 patients received prophylactic antibiotics for retained bullets or durotomies, only 2 patients had postoperative wound infections and 4 had extraspinal infections from retained bullets. All inpatient mortalities (n = 5) were patients with cervical pSI. Thirteen patients with GSW obtained MRI scans without complications. Among our cohort, only 65 patients had follow-up with a median follow-up period of 1.25 (range, 1-60) months. CONCLUSIONS: Management of pSI in urban trauma centers is complex, as these victims routinely have polytrauma that takes precedence. Indications for surgical intervention are narrow and secondary to surgery for polytrauma. External bracing may be overutilized. The efficacy of prophylactic antibiotics remains unclear. MRI can contribute valuable information but is limited by uncertainty regarding bullet compatibility. Lack of follow-up limits the study of this population.

Data supporting the forecast of electricity generation capacity from non-conventional renewable energy sources in Colombia.

The data included in this study was calculated based on data provided by the national project registry provided by the Colombian government. The data forecasts the evolution of the power generation capacity registered in non-conventional renewable energy source projects in three scenarios of implementation of the power generation capacity registered in the projects. Results can be used to benchmark non-conventional renewable energy sources in Colombia, interpret the effectiveness of renewable policies, and monitor the evolution of non-conventional renewable-based power generation. The data presented in the article relates to the research study: A look to the electricity generation from non-conventional renewable energy sources in Colombia [1].

Data supporting the improvement of forecasting and control of electricity consumption in hotels.

Improving and managing the electricity efficiency in hotel facilities is essential to reduce the hotel operation costs and its environmental impacts. The data presented shows the evolution of the electricity consumption and management between 2013 and 2015 in two hotel facilities in Cuba (one beach hotel and one city hotel). The data additionally includes the daily measures used to develop control tools for an energy management system. The data presented in the article relates to the research study: Tools to improve forecasting and control of the electricity consumption in hotels Cabello et al., 2016, and it corresponds to the energy audits developed in one beach hotel (Hotel A) and one city hotel (Hotel B) in Cuba.