An in-plane photoelectric effect in two-dimensional electron systems for terahertz detection.

Many mid- and far-infrared semiconductor photodetectors rely on a photonic response, when the photon energy is large enough to excite and extract electrons due to optical transitions. Toward the terahertz range with photon energies of a few milli-electron volts, classical mechanisms are used instead. This is the case in two-dimensional electron systems, where terahertz detection is dominated by plasmonic mixing and by scattering-based thermal phenomena. Here, we report on the observation of a quantum, collision-free phenomenon that yields a giant photoresponse at terahertz frequencies (1.9 THz), more than 10-fold as large as expected from plasmonic mixing. We artificially create an electrically tunable potential step within a degenerate two-dimensional electron gas. When exposed to terahertz radiation, electrons absorb photons and generate a large photocurrent under zero source-drain bias. The observed phenomenon, which we call the "in-plane photoelectric effect," provides an opportunity for efficient direct detection across the entire terahertz range.

Multi-disciplinary Leadership to Mitigate COVID-19 in an Austere West African Military Environment.

INTRODUCTION: The COVID-19 pandemic created challenges for forward-deployed military units to Western Africa. Austere military environments afford multiple avenues to transmit COVID-19 amongst service members. MATERIALS AND METHODS: A COVID-19 outbreak on a military base in Western Africa spanning over 100 days is statistically analyzed using a Pearson's correlation coefficient. Furthermore, a COVID-19 reproductive number (R0) is evaluated to examine the relationship between specific command-directed policies to mitigate COVID-19 transmission. RESULTS: The multidisciplinary partnership of military command, medical, and public health leadership implemented evidence-based and epidemiologically informed COVID-19 preventive base-wide policies, including appropriate isolation/quarantine policies. The R0 for the outbreak was 0.03 and remained <1 for the outbreak duration. This base remained COVID-19 free for multiple weeks after policy implementation. CONCLUSIONS: The implementation of practical mitigating base-wide policies through seamless communication between military command/medical/public health leadership resolved the COVID-19 outbreak while maintaining mission readiness. Weekly COVID-19 testing epidemiological data may be utilized by commanders to direct further decision-making on tightening/loosening base-wide policy restrictions for continued mission-essential operations, e.g., security, food service, or airfield operations.

Freeze branding: a novel injurious mechanism for humans.

Freeze branding was first performed in 1966 to identify animals for agricultural purposes, and remains relevant today in veterinary medicine. In contrast, human branding for aesthetics, punishment, identification, and purported medicinal benefits is standardly performed through transfer of thermal energy via heat. Uniquely, this case report documents the first description of freeze branding as a mechanism of injury in humans resulting in a 0.25% total body surface area mixed partial thickness/full thickness forearm burn that was managed non-operatively with out-patient daily wound care over six-months without morbidity. The overall clinical management of freeze branding injuries, anticipated sequelae, and co-morbid diseases will be discussed to provide an educational foundation for future clinical encounters.

Extracutaneous Manifestations of Calciphylaxis: Ogilvie's Syndrome With Perforation.

Calciphylaxis or calcific uremic arteriolopathy is a rare entity associated with the end-stage renal disease that presents with necrotic cutaneous lesions that may require surgical management. Extracutaneous manifestations of calciphylaxis including visceral ischemia have been reported; however, surgical intervention for colonic ischemia has only been reported twice. We report a 49-year-old male with calciphylaxis who subsequently developed Ogilvie's syndrome complicated by perforation requiring total abdominal colectomy with end ileostomy. Surgeons treating this disease should have a heightened awareness of the extracutaneous sequelae of calciphylaxis.

Single-photon emission from single-electron transport in a SAW-driven lateral light-emitting diode.

The long-distance quantum transfer between electron-spin qubits in semiconductors is important for realising large-scale quantum computing circuits. Electron-spin to photon-polarisation conversion is a promising technology for achieving free-space or fibre-coupled quantum transfer. In this work, using only regular lithography techniques on a conventional 15 nm GaAs quantum well, we demonstrate acoustically-driven generation of single photons from single electrons, without the need for a self-assembled quantum dot. In this device, a single electron is carried in a potential minimum of a surface acoustic wave (SAW) and is transported to a region of holes to form an exciton. The exciton then decays and creates a single optical photon within 100 ps. This SAW-driven electroluminescence, without optimisation, yields photon antibunching with g(2)(0) = 0.39 ± 0.05 in the single-electron limit (g(2)(0) = 0.63 ± 0.03 in the raw histogram). Our work marks the first step towards electron-to-photon (spin-to-polarisation) qubit conversion for scaleable quantum computing architectures.

Prehospital whole blood resuscitation prevents coagulopathy and improves acid-base status at hospital arrival in a nonhuman primate hemorrhagic shock model.

BACKGROUND: Hemorrhage remains the primary cause of preventable death in civilian and military trauma. The Committee on Tactical Combat Casualty Care recommends prehospital (PH) resuscitation with whole blood (WB). However, 6% hetastarch in lactated electrolyte (HEX) and crystalloids are more commonly available and used for PH resuscitation in military and civilian environments, respectively. The mechanistic benefits of PH WB resuscitation have not been well studied and remain to be elucidated. STUDY DESIGN AND METHODS: The aim of this study was to evaluate the differences in simulated PH WB and HEX resuscitation, specifically with regards to coagulation, physiologic, and metabolic outcomes to better elucidate the mechanistic benefits of WB. In a randomized study, the physiologic, coagulation, and metabolic responses to simulated PH WB (n = 12) or HEX (n = 12) were evaluated in a nonhuman primate model of severe polytraumatic hemorrhagic shock. RESULTS: Notable findings included 1) equivalence of shock reversal between simulated PH WB and HEX treatment groups as determined by hemodynamics and base deficit and 2) prevention of coagulopathy at simulated hospital arrival with initial WB resuscitation as determined by viscoelastic and plasmatic coagulation assays. CONCLUSION: The major benefit of WB, as compared to HEX, in simulated PH resuscitation appears to be prevention of coagulopathy at hospital arrival. Both fluids effectively reversed shock in this model, implying that efficacious provision preload (cardiac output support and hence oxygen delivery) and coagulation proteins (prevention of coagulopathy) are mechanisms underlying WB's effectiveness in early resuscitation of hemorrhagic shock.

Whole blood and Hextend: Bookends of modern tactical combat casualty care field resuscitation and starting point for multifunctional resuscitation fluid development.

BACKGROUND: Hemorrhage is the leading cause of preventable death in traumatically injured civilian and military populations. Prehospital resuscitation largely relies on crystalloid and colloid intravascular expansion, as whole blood and component blood therapy are logistically arduous. In this experiment, we evaluated the bookends of Tactical Combat Casualty Care Guidelines recommendations of prehospital resuscitation with Hextend and whole blood in a controlled hemorrhagic shock model within non-human primates, as means of a multifunctional resuscitative fluid development. METHODS: In the nonhuman primate, a multiple injuries model was used, consisting of a musculoskeletal injury (femur fracture), soft tissue injury (15-cm laparotomy), and controlled hemorrhage to a mean arterial pressure of 20 mm Hg, demarcating the beginning of the shock period. Animals were randomized to prehospital interventions of whole blood or Hextend at T = 0 minutes, and at T = 90 minutes definitive surgical interventions and balanced sanguineous damage control resuscitation could be implemented. All animals were euthanized at T = 480 minutes. Data are expressed as mean ± SEM; significance, p < 0.05. RESULTS: No significant differences in survival (83% vs. 100%; p = 0.3), tissue perfusion (EtCO2 and StO2) or endpoints of resuscitation (base deficit, lactate, pH) between Hextend and whole blood were identified. Second, whole blood compared with Hextend demonstrated significantly earlier normalization of clot formation time, maximal clot firmness, and α angle. CONCLUSION: A future multifunctional resuscitative fluid including an asanguineous, oncotic, non-oxygen-carrying component to facilitate intravascular volume expansion, and a component with synthetic coagulation factors and fibrinogen to deter coagulopathy may show equivalence to whole blood. LEVEL OF EVIDENCE: N/A: Study type: translational animal model.

Traumatic Hemothorax Blood Contains Elevated Levels of Microparticles that are Prothrombotic but Inhibit Platelet Aggregation.

OBJECTIVES: Autotransfusion of shed blood from traumatic hemothorax is an attractive option for resuscitation of trauma patients in austere environments. However, previous analyses revealed that shed hemothorax (HX) blood is defibrinated, thrombocytopenic, and contains elevated levels of D-dimer. Mixing studies with normal pooled plasma demonstrated hypercoagulability, evoking concern for potentiation of acute traumatic coagulopathy. We hypothesized that induction of coagulopathic changes by shed HX blood may be due to increases in cellular microparticles (MP) and that these may also affect recipient platelet function. METHODS: Shed HX blood was obtained from 17 adult trauma patients under an Institutional Review Board approved prospective observational protocol. Blood samples were collected every hour up to 4 h after thoracostomy tube placement. The corresponding plasma was isolated and frozen for analysis. The effects of shed HX frozen plasma (HFP) and isolated HX microparticles (HMP) on coagulation and platelet function were assessed through mixing studies with platelet-rich plasma at various dilutions followed by analysis with thromboelastometry (ROTEM), platelet aggregometry (Multiplate), enzyme-linked immunosorbent assays, and flow cytometry. Furthermore, HFP was assessed for von Willebrand factor antigen levels and multimer content, and plasma-free hemoglobin. RESULTS: ROTEM analysis demonstrated that diluted HFP and isolated HMP samples decreased clotting time, clotting formation time, and increased α angle, irrespective of sample concentrations, when compared with diluted control plasma. Isolated HMP inhibited platelet aggregation in response to adenosine diphosphate, arachidonic acid, and collagen. HFP contained elevated levels of fibrin-degradation products and tissue factor compared with control fresh frozen plasma samples. MP concentrations in HFP were significantly increased and enriched in events positive for phosphatidylserine, tissue factor, CD235, CD45, CD41a, and CD14. von Willebrand factor (vWF) multimer analysis revealed significant loss of high molecular weight multimers in HFP samples. Plasma-free hemoglobin levels were 8-fold higher in HFP compared with fresh frozen plasma. CONCLUSION: HFP induces plasma hypercoagulability that is likely related to increased tissue factor and phosphatidylserine expression originating from cell-derived MP. In contrast, platelet dysfunction is induced by HMP, potentially aggravated by depletion of high molecular weight multimers of vWF. Thus, autologous transfusion of shed traumatic hemothorax blood may induce a range of undesirable effects in patients with acute traumatic coagulopathy.

Short-Term Outcomes and Complications of Damage Control and Definitive Laparotomy in Deployed Combat Environments: 2002 to 2011.

INTRODUCTION: Damage control laparotomy (DCL) in an austere environment is an evolving surgical modality. METHODS: A retrospective evaluation of all patients surviving 24 hours who underwent a laparotomy from 2002 to 2011 in Iraq and Afghanistan was performed. DCL was defined as a patient undergoing laparotomy at two distinct North American Treaty Organization (NATO) Role 2 or 3 medical treatment facilities (MTFs); a NATO Roles 2 and 3 MTFs, and/or having the International Classification of Diseases, 9th Revision, Clinical Modification procedure code 54.12, for reopening of recent laparotomy site. Definitive laparotomy (DL) was defined as patients undergoing one operative procedure at one NATO Role 2 or 3 MTF. Demographic data including injury severity scores, hematological transfusion, mortality, intraperitoneal or retroperitoneal operative interventions, and complications were compared. RESULTS: DCL composed of 26.5% (n = 331) of all 1,248 laparotomies performed between March 2002 and September 2011. Total intra-abdominal, acute respiratory distress syndrome, and thromboembolic complications for DCL versus DL were 8.5% and 5.6% (p = 0.07), 2.1% and 0.8% (p = 0.06), and 1.5% and 0.7% (p = 0.17), respectively. Theater discharge mortality from DCL and DL were 1.5% (n = 5), and 1.4% (n = 13) (p = 0.90), respectively. CONCLUSIONS: In conclusion, excluding deaths with the first 24 hours, DCL and DL had comparable mortality and complication rates at NATO Roles 2 and 3 MTFs.

Control of severe intra-abdominal hemorrhage with an infusible platelet-derived hemostatic agent in a nonhuman primate (rhesus macaque) model.

BACKGROUND: Hemorrhage remains the leading cause of potentially survivable trauma mortality. Recent reports indicate that injuries sustained in noncompressible anatomic locations (i.e., truncal and junctional) account for 86.5% of hemorrhage-related deaths. Infusible human platelet-derived hemostatic agents (hPDHAs) represent a promising strategy to reduce blood loss from noncompressible injuries. Here, we evaluate the hemostatic efficacy of a lyophilized hPDHA in a rhesus macaque model of severe, uncontrolled hemorrhage. METHODS: Hemorrhage was induced via laparoscopic 60% left-lobe hepatectomy in anesthetized rhesus macaques (T = 0 minute). Treatment infusion began with an 11-mL bolus (T = 5-6 minutes) of either 5% albumin solution (control; n = 8) or hPDHA (1.2 × 10(10) platelet equivalents, n = 8), followed by 2.8-mL/min 0.9% normal saline at T = 6-20 minutes. Resuscitation continued with normal saline (0.22 mL/kg/min) to a total volume of 20 mL/kg at T = 120 minutes, at which time surgical hemostasis was achieved and percent blood loss quantified. Animals were monitored until T = 480 minutes and then euthanized, and necropsy was performed with emphasis on intravascular and end-organ thrombi. Data are expressed as mean ± SEM; significance, p < 0.05. RESULTS: Both groups exhibited a ∼70% decrease in mean arterial pressure (MAP) from T = 0-5 minutes. Percent blood loss was 44.2 ± 3.9% in hPDHA animals, and 44.3 ± 3.3% in controls. Survival rates were 4 of 8 for hPDHA animals and 7 of 8 for controls. Regardless of treatment, percent blood loss was greater (p < 0.02) in nonsurviving animals (55 ± 2%, n = 5) compared with surviving animals (42% ± 3%, n = 11). No pathologic intravascular thrombi were observed in either group. CONCLUSION: The isolated administration of hPDHA did not significantly reduce blood loss; however, thrombocytopenia was not present in the model, and clinically, platelets would be administered in combination with plasma. Mortality was not statistically different between groups (p = 0.14) but was related to blood loss. Future studies should consider the use of hPDHA in combination with additional therapeutics (e.g., factors) and a model that incorporates thrombocytopenia or platelet dysfunction.

Evaluation of the Effectiveness of the 2008 Postsplenectomy Vaccination Joint Theater Trauma System Clinical Practice Guideline.

OBJECTIVES: Postsplenectomy vaccination (PSV) in an austere environment to minimize overwhelming postsplenectomy infection is challenging. We evaluated the clinical impact of a March 2008 clinical practice guideline (CPG) dictating immediate PSV at North American Treaty Organization Role 3 medical treatment facilities and subsequent complications. METHODS: Utilizing U.S. military medical databases, we characterized all U.S. patients with a splenic injury from November 2002 to January 2012 by their surgical management: laparotomy with splenectomy (LWS), laparotomy without splenectomy, or nonoperative management. Relevant data including demographics, vaccinations, and documented bacterial and fungal isolates were obtained. RESULTS: LWS comprised 63.6% of the 409 patients with a splenic injury from 2002 to 2012. The implementation of the PSV CPG improved overall vaccination compliance from 48.9% pre-PSV CPG to 86.9% post-PSV CPG (p < 0.01). It was found that 1.3% (2/159) of completely vaccinated LWS patients compared with 0% (0/101) of the incompletely vaccinated LWS patients had Streptococcus pneumoniae isolates in 391.0 and 251.4 follow-up years, respectively (p = 0.52). No Neisseria meningitidis or Haemophilus influenzae isolates were identified. CONCLUSIONS: PSV CPG implementation improved theater vaccination without increasing the incidence of encapsulated organisms.

Establishing the reliability of rhesus macaque social network assessment from video observations.

Understanding the properties of a social environment is important for understanding the dynamics of social relationships. Understanding such dynamics is relevant for multiple fields, ranging from animal behaviour to social and cognitive neuroscience. To quantify social environment properties, recent studies have incorporated social network analysis. Social network analysis quantifies both the global and local properties of a social environment, such as social network efficiency and the roles played by specific individuals, respectively. Despite the plethora of studies incorporating social network analysis, methods to determine the amount of data necessary to derive reliable social networks are still being developed. Determining the amount of data necessary for a reliable network is critical for measuring changes in the social environment, for example following an experimental manipulation, and therefore may be critical for using social network analysis to statistically assess social behaviour. In this paper, we extend methods for measuring error in acquired data and for determining the amount of data necessary to generate reliable social networks. We derived social networks from a group of 10 male rhesus macaques, Macaca mulatta, for three behaviours: spatial proximity, grooming and mounting. Behaviours were coded using a video observation technique, where video cameras recorded the compound where the 10 macaques resided. We collected, coded and used 10 h of video data to construct these networks. Using the methods described here, we found in our data that 1 h of spatial proximity observations produced reliable social networks. However, this may not be true for other studies due to differences in data acquisition. Our results have broad implications for measuring and predicting the amount of error in any social network, regardless of species.

Interatrial Bronchogenic Cyst Resection.

Interatrial bronchogenic cysts are rare entities, and the long-term clinical sequelae are unknown. This case report details the removal of a large (>4 cm) interatrial bronchogenic cyst that had been present for more than 10 years. Surgical resection remains the current standard of therapy when encountering an interatrial mass.

Nonoperative management of splenic injury in combat: 2002-2012.

BACKGROUND: Selective nonoperative management of combat-related blunt splenic injury (BSI) is controversial. We evaluated the impact of the November 2008 blunt abdominal trauma clinical practice guideline that permitted selective nonoperative management of some patients with radiological suggestion of hemoperitoneum on implementation of nonoperative management (NOM) of splenic injury in austere environments. METHODS: Retrospective evaluation of patients with splenic injuries from November 2002 through January 2012 in Iraq and Afghanistan was performed. International Classification of Diseases, 9th Revision, Clinical Modification procedure codes identified patients as laparotomy with splenectomy, or NOM. Delayed operative management had no operative intervention at earlier North American Treaty Organization (NATO) medical treatment facilities (MTFs), and had a definitive intervention at a latter NATO MTFs. Intra-abdominal complications and overall mortality were juxtaposed. RESULTS: A total of 433 patients had splenic injuries from 2002 to 2012. Initial NOM of BSI from 2002 to 2008 compared to 2009-2012 was 44.1% and 47.2%, respectively (p=0.75). Delayed operative management and NOM completion had intra-abdominal complication and mortality rates of 38.1% and 9.1% (p<0.01), and 6.3% and 8.1% (p=0.77). CONCLUSIONS: Despite high-energy explosive injuries, NATO Role II MTFs radiological constraints and limited medical resources, hemodynamically normal patients with BSI and low abdominal abbreviated injury scores underwent NOM in austere environments.

An 8-year review of operation enduring freedom and operation iraqi freedom resuscitative thoracotomies.

BACKGROUND: Appropriate indications for resuscitative thoracotomy (RT) in an austere environment continue to evolve; the aim of this study was to determine survival and to analyze demographics of survivors within U.S. military personnel undergoing RT. METHODS: A retrospective review was performed of all U.S. soldiers who underwent thoracotomy in theater during Operation Iraqi Freedom and Operation Enduring Freedom. After individualized review, patients in extremis or who lost pulses and had their thoracotomy performed within 10 minutes of arrival to the emergency department were included. The primary outcome was survival at final hospital discharge, and secondary outcomes included demographics associated with survival. RESULTS: Between January 2003 and May 2010, 81 U.S. military personnel met inclusion criteria for RT in theater. As low as 6.7% (3/45) of patients receiving prehospital cardiopulmonary resuscitation were alive at final hospital discharge. Survival from RT after explosive/blast injury, penetrating (gunshot wound), and blunt trauma were 16.3% (8/49), 0% (0/28), and 0% (0/4), respectively. Patients with primary explosive/blast extremity trauma undergoing RT had a survival of 27.3% (6/22). Higher initial oxygen saturations, larger volume of crystalloids and blood products infused, and higher extremity abbreviated injury score were all associated with survival. CONCLUSIONS: Combat casualties who present pulseless or in extremis who were injured as a result of an explosive/blast injury mechanism resulting in a primary extremity injury may have a survival benefit from undergoing a RT in an austere environment.

Nontherapeutic laparotomy in American combat casualties: a 10-year review.

BACKGROUND: The civilian literature has expanded the indications for selective nonoperative management (SNOM) for abdominal trauma to minimize morbidity from nontherapeutic laparotomies (NTLs); however, this treatment modality remains controversial and rare in austere settings. This study aimed to quantify the percentage of NTL and incidence of failed SNOM performed in theater and to define each of their respective intra-abdominal-related morbidities. METHODS: A retrospective evaluation of all patients who underwent a laparotomy from 2002 to 2011 during Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) was performed for patients who survived a minimum of 24 hours. With the use of DRG International Classification of Diseases--9th Rev. procedure codes, a therapeutic laparotomy was defined by the presence of a defined intraperitoneal or retroperitoneal procedure; an NTL was defined by the absence of a defined intraperitoneal or retroperitoneal procedure. Second, patients transferred from North American Treaty Organization Role II to Role III medical treatment facilities to be operated on were deemed failed SNOM. Finally, intra-abdominal complications and mortality were identified for patients undergoing therapeutic laparotomy, NTL, and failed SNOM. RESULTS: Blunt, burn, and penetrating injuries accounted for 38.5% (n = 490), 1.1% (n = 14), and 60.4% (n = 769) of all laparotomies in the OEF and OIF, respectively. Thirty-two percent of all laparotomies performed during the OEF and OIF campaigns were NTL; specifically, the NTL rates in OEF and OIF were 38.2% and 28.6%, respectively. In addition, 31.6% and 32.2% of all penetrating and blunt injury mechanisms resulted in an NTL, respectively. The percentage of all patients identified as failing SNOM was 7.5% (n = 95). The early intra-abdominal complication rate for failed SNOM and for all patients undergoing NTL was 2.1% and 1.7%, respectively. CONCLUSION: The OIF and OEF combined NTL rate was 32.1%, with an associated 1.7% intra-abdominal early complication rate. The infrequent application of SNOM in a deployed military environment is likely secondary to unpredictable fragmentation trajectories and related blast injury patterns, limited medical resources including computed tomography, and a complex aeromedical evacuation system preventing serial observation. LEVEL OF EVIDENCE: Epidemiologic study, level IV.

Mucormycosis attributed mortality: a seven-year review of surgical and medical management.

INTRODUCTION: Historically, mucormycosis infections have been associated with high mortality. The purpose of this study was to determine the incidence, associated mortality, and management strategies of mucormycosis in a major burn center. METHODS: A retrospective review was performed via obtaining all patients with mucormycosis admitted from January 2003 to November 2009 at our adult burn center was performed obtaining demographic data relevant to fungal burn wound infection or colonization. RESULTS: The incidence of mucormycosis at our facility was 4.9 per 1000 admissions; specifically, 11 military casualties and one civilian were diagnosed with mucormycosis. The median percentage Total Body Surface Area (TBSA) burned, 11 patients, or open wound, one patient, was 60 (IQR, 54.1-80.0), and the incidence of documented inhalation injury was 66.7% (8 of 12). Ten patients had surgical amputations. A median of eight days (IQR, 3.5-74.5) elapsed from diagnosis of mucormycosis until death in the 11 patients who expired. The overall mortality was 92%; however, autopsy attributed mucormycosis mortality was 54.5% (6 of 11) with all six patients having invasive mucormycosis. CONCLUSION: Aggressive surgical intervention should be undertaken for invasive mucormycosis; additionally, implementation of standardized protocols for patients with large soft tissue injuries may mitigate mucormycosis superimposition.