High-Pressure Inactivation of Bacillus cereus in Human Breast Milk

Although Holder pasteurization is the recommended method for processing breast milk, it does affect some of its nutritional and biological properties and is ineffective at inactivating spores. The aim of this study was to find and validate an alternative methodology for processing breast milk to increase its availability for newborn babies and reduce the financial loss associated with discarding milk that has become microbiologically positive. We prepared two series of breast milk samples inoculated with the Bacillus cereus (B. cereus) strain to verify the effectiveness of two high-pressure treatments: (1) 350 MPa/5 min/38 °C in four cycles and (2) cumulative pressure of 350 MPa/20 min/38 °C. We found that the use of pressure in cycles was statistically more effective than cumulative pressure. It reduced the number of spores by three to four orders of magnitude. We verified that the method was reproducible. The routine use of this method could lead to an increased availability of milk for newborn babies, and at the same time, reduce the amount of wasted milk. In addition, high-pressure treatment preserves the nutritional quality of milk.

Ventilators, Settings, Autotitration Algorithms

The choice of a ventilator model for a single patient is usually based on parameters such as size (portability), presence or absence of battery and ventilatory modes. However, there are many details within each ventilator model about triggering, pressurisation or autotitration algorithms that may go unnoticed, but may be important or may justify some drawbacks that may occur during their use in individual patients. This review is intended to emphasize these differences. Guidance is also provided on the operation of autotitration algorithms, in which the ventilator is able to take decisions based on a measured or estimated parameter. It is important to know how they work and their potential sources of error. Current evidence on their use is also provided.

A Fire Incident Case at a Radiodiagnostic Center of a Tertiary Care Hospital: Methods for Reduction in Fatality by Smoke Evacuation

For the general public, healthcare facilities are always a safe and secure place for treatment. Generally, healthcare institutions are equipped to deal with exterior interruptions, but circumstances brought on by internal risks are more serious and frequently require an emergency evacuation of the facility. An incident happened at the radiodiagnostic setup of a tertiary care institute in North India. This fire incident created panic among staff and patients. At the place of casualty, there were around 150 persons, including staff, patients, and their attendants. Immediately after the confirmation of the fire incident, the fire department and security department took action in the form of fire control and smoke evacuation. Though six fire handling staff required minor emergency services for asphyxia due to smoke inhalation and were cured by oxygen support only, none of the patients was affected due to timely smoke evacuation. Most often, smoke management techniques implemented are compartmentation, pressurization, dilution, ventilation, buoyancy, and airflow. So, we concluded that the step of timely smoke evacuation and preventing the spread of smoke by various methods help to reduce fatality due to smoke. The training programs and mock drills give stakeholders the needed knowledge, skills, and practice they need to safeguard patients and employees.

Effects of arterial blood supply on the survival of reverse-flow island flaps: an experimental study

OBJECTIVES

This study aimed to investigate the effect of arterial blood supply on the survival area of retrograde island flap.

METHODS

The vein and saphenous artery in rabbits were selected to design the reverse-flow island flap experimental model. Forty rabbits were randomly divided into four groups: control group (group A), partial anastomosis of the saphenous artery group (group B), partial anastomosis of the vein group (group C), and no superficial vein group (group D). Flap survival was observed postoperatively, the survival area was measured, and the survival rate was compared. Blood distribution in the flap at different time points was observed by radionuclide imaging.

RESULTS

The blood vessel distribution and blood cell status were observed histologically. The survival rate of flaps in group B was higher than that of the other three groups (P < 0.05). The radioactive material (RM) could be seen clearly in group B, whereas those in groups A, C, and D existed transiently. The RM in group B was higher than that in groups A, C, and D (P < 0.05). On postoperative day 10, group B had more capillary regeneration and blood cells than the other three groups (P < 0.05).

CONCLUSIONS

Increasing blood supply can improve the survival rate of flaps, but simply promoting venous return has no significant effect on the survival rate of flaps.

Survival estimates across five life stages of redfin (Perca fluviatilis) exposed to simulated pumped-storage hydropower stressors

The global prevalence of pumped-storage hydropower (PSH) is expected to grow exponentially as countries transition to renewable energy sources. Compared to conventional hydropower, little is currently known regarding PSH impacts on aquatic biota. This study estimated the survival of five life stages (egg, two larval stages, juvenile and adult) of redfin (European) perch (Perca fluviatilis) following passage through a PSH facility during the pumping phase. This was achieved by simulating the individual stressors expected to occur during passage through a 2000-MW PSH facility using laboratory-simulated (shear strain and extreme compression) and modelling (blade strike, BS) approaches. Our results indicate that redfin could survive the shear, pressure and BS stressors expected within the PSH facility, but impacts varied among life stages. Juvenile survival was >70% across all shear strain rates, while the survival of eggs and larvae declined markedly as strain rate increased. All life stages had high survival when exposed to rapid compression and BS. The high survival of redfin to the stressors tested suggests the PSH facility could facilitate the passage of redfin during the pumping phase from the lower to the higher elevation reservoir. This outcome would be welcomed in situations where the species is native, but could have adverse implications for the conservation of native biota where the species is considered a pest.

Study of fallopian tube anatomy and mechanical properties to determine pressure limits for endoscopic exploration

Falloposcopy is the endoscopic examination of the fallopian tubes, which are challenging to access due to their deep body location, small opening from the uterus, and lumen filled with plicae. We and others have developed endoscopes that are inserted through the uterus guided by a hysteroscope into the tubal ostium. To better understand how to utilize these endoscopes either as standalone devices or in concert with everting delivery balloons, a preliminary study of anatomy and mechanical behavior was performed ex vivo on porcine and human fallopian tubes. Segments of fallopian tubes from the isthmus, ampulla and infundibulum were inflated with saline either to bursting or held at sub-burst pressures with saline or a saline-filled balloon. Formalin fixed, paraffin embedded tissue sections stained with Masson's trichrome were examined for damage to the mucosa and muscularis. Porcine fallopian tubes tolerated saline pressurization at 15 psi for 1 minute without morphological damage. Balloon inflation to 15 psi caused no apparent damage to the muscle layer or rupture of the fallopian tube, but balloon movement within the tube can denude the mucosal epithelial layer. Human fallopian tubes averaged higher burst pressure values than porcine tubes. Under pressurization, the external tube diameter expanded by minimal to moderate amounts. Human and porcine tissues were similar in histological appearance. These studies suggest that moderate pressurization is acceptable but will not appreciably expand the fallopian tube diameter. The results also indicate that pigs are a reasonable model to study damage from falloscopy as seen in human tissue.

Influences of Different Architectures on the Thermodynamic Performance and Network Structure of Aircraft Environmental Control System

The environmental control system (ECS) is one of the most important systems in the aircraft used to regulate the pressure, temperature and humidity of the air in the cabin. This study investigates the influences of different architectures on the thermal performance and network structure of ECS. The refrigeration and pressurization performances of ECS with four different architectures are analyzed and compared by the endoreversible thermodynamic analysis method, and their external and internal responses have also been discussed. The results show that the connection modes of the heat exchanger have minor effects on the performance of ECSs, but the influence of the air cycle machine is obvious. This study attempts to abstract the ECS as a network structure based on the graph theory, and use entropy in information theory for quantitative evaluation. The results provide a theoretical basis for the design of ECS and facilitate engineers to make reliable decisions.

Unravelling the Molecular Mechanisms Underlying the Protective Effect of Lactate on the High-Pressure Resistance of Listeria monocytogenes

Formulations with lactate as an antimicrobial and high-pressure processing (HPP) as a lethal treatment are combined strategies used to control L. monocytogenes in cooked meat products. Previous studies have shown that when HPP is applied in products with lactate, the inactivation of L. monocytogenes is lower than that without lactate. The purpose of the present work was to identify the molecular mechanisms underlying the piezo-protection effect of lactate. Two L. monocytogenes strains (CTC1034 and EGDe) were independently inoculated in a cooked ham model medium without and with 2.8% potassium lactate. Samples were pressurized at 400 MPa for 10 min at 10 °C. Samples were subjected to RNA extraction, and a shotgun transcriptome sequencing was performed. The short exposure of L. monocytogenes cells to lactate through its inoculation in a cooked ham model with lactate 1h before HPP promoted a shift in the pathogen’s central metabolism, favoring the metabolism of propanediol and ethanolamine together with the synthesis of the B12 cofactor. Moreover, the results suggest an activated methyl cycle that would promote modifications in membrane properties resulting in an enhanced resistance of the pathogen to HPP. This study provides insights on the mechanisms developed by L. monocytogenes in response to lactate and/or HPP and sheds light on the understanding of the piezo-protective effect of lactate.

The Aircraft Cabin Environment

Travel by air is a safe means of transport, but from the physiologic point of view it is a means of putting people at risk as well as a potential means of spreading infectious disease. Atmospheric pressure falls with altitude and above about 10,000 feet, blood desaturation leads to hypoxia. The aircraft cabin is pressurized to maintain an effective altitude below 8000 feet, which provides adequate protection for healthy travelers. Those individuals with cardiopulmonary impairment or other conditions affecting fitness to travel should seek advice from the airline in consultation with their medical provider. People are the primary source of microorganisms in aircraft cabins and are the most important reservoirs of infectious agents on aircraft. Recirculated cabin air is filtered to remove microorganisms, but this does not prevent person-to-person spread of infectious disease in vulnerable people. The World Health Organization and Centers for Disease Control and Prevention produce guidelines; and people with febrile illnesses should postpone air travel.

Rapid drinking challenge during high-resolution manometry is complementary to timed barium esophagogram for diagnosis and follow-up of achalasia

BACKGROUND

Esophageal stasis is a hallmark of achalasia. Timed barium esophagogram (TBE) is used to measure stasis but exposes patients to ionizing radiation. It is suggested that esophageal stasis can be objectified on high-resolution manometry (HRM) as well using a rapid drinking challenge test (RDC). We aimed to assess esophageal stasis in achalasia by a RDC during HRM and compare this to TBE.

METHODS

Thirty healthy subjects (15 male, age 40 [IQR 34-49]) and 90 achalasia patients (53 male, age 47 [36-59], 30 untreated/30 treated symptomatic/30 treated asymptomatic) were prospectively included to undergo HRM with RDC and TBE. RDC was performed by drinking 200 mL of water. Response to RDC was measured by basal and relaxation pressure in the esophagogastric junction (EGJ) and esophageal pressurization during the last 5 seconds.

KEY RESULTS

EGJ basal and relaxation pressure during RDC were higher in achalasia compared to healthy subjects (overall P < .01). Esophageal body pressurization was significantly higher in untreated (43 [33-35 mm Hg]) and symptomatic treated patients (25 [16-32] mm Hg) compared to healthy subjects (6 [3-7] mm Hg) and asymptomatic treated patients (11 [8-15] mm Hg, overall P < .01). A strong correlation was observed between esophageal pressurization during RDC and barium column height at 5 minutes on TBE (r = .75, P < .01), comparable to the standard predictor of esophageal stasis, IRP (r = .66, P < .01).

CONCLUSIONS & INFERENCES

The RDC can reliably predict esophageal stasis in achalasia and adequately measure treatment response to a degree comparable to TBE. We propose to add this simple test to each HRM study in achalasia patients.

Room-Temperature Pressure Synthesis of Layered Black Phosphorus-Graphene Composite for Sodium-Ion Battery Anodes

Sodium-ion batteries offer an attractive option for grid-level energy storage due to the high natural abundance of sodium and low material cost of sodium compounds. Phosphorus (P) is a promising anode material for sodium-ion batteries, with a theoretical capacity of 2596 mAh/g. The red phosphorus (RP) form has worse electronic conductivity and lower initial Coulombic efficiency than black phosphorus (BP), but high material cost and limited production capacity have slowed the development of BP anodes. To address these challenges, we have developed a simple and scalable method to synthesize layered BP/graphene composite (BP/rGO) by pressurization at room temperature. A carbon-black-free and binder-free BP/rGO anode prepared with this method achieved specific charge capacities of 1460.1, 1401.2, 1377.6, 1339.7, 1277.8, 1123.78, and 720.8 mAh/g in a rate capability test at charge and discharge current densities of 0.1, 0.5, 1, 5, 10, 20, and 40 A/g, respectively. In a cycling performance test, after 500 deep cycles, the capacity of BP/rGO anodes stabilized at 1250 and 640 mAh/g at 1 and 40 A/g, respectively, which marks a significant performance improvement for sodium-ion battery anodes.

Stomata actively regulate internal aeration of the sacred lotus Nelumbo nucifera

The sacred lotus Nelumbo nucifera (Gaertn.) possesses a complex system of gas canals that channel pressurized air from its leaves, down through its petioles and rhizomes, before venting this air back to the atmosphere through large stomata found in the centre of every lotus leaf. These central plate stomata (CPS) lie over a gas canal junction that connects with two-thirds of the gas canals within the leaf blade and with the larger of two discrete pairs of gas canals within the petiole that join with those in the rhizome. It is hypothesized that the lotus actively regulates the pressure, direction and rate of airflow within its gas canals by opening and closing these stomata. Impression casting the CPS reveal that they are open in the morning, close at midday and reopen in the afternoon. The periodic closure of the CPS during the day coincides with a temporary reversal in airflow direction within the petiolar gas canals. Experiments show that the conductance of the CPS decreases in response to increasing light level. This behaviour ventilates the rhizome and possibly directs benthic CO2 towards photosynthesis in the leaves. These results demonstrate a novel function for stomata: the active regulation of convective airflow.

Formulation and acoustic studies of a new phase-shift agent for diagnostic and therapeutic ultrasound

Recent efforts in the area of acoustic droplet vaporization with the objective of designing extravascular ultrasound contrast agents has led to the development of stabilized, lipid-encapsulated nanodroplets of the highly volatile compound decafluorobutane (DFB). We developed two methods of generating DFB droplets, the first of which involves condensing DFB gas (boiling point from -1.1 to -2 °C) followed by extrusion with a lipid formulation in HEPES buffer. Acoustic droplet vaporization of micrometer-sized lipid-coated droplets at diagnostic ultrasound frequencies and mechanical indices were confirmed optically. In our second formulation methodology, we demonstrate the formulation of submicrometer-sized lipid-coated nanodroplets based upon condensation of preformed microbubbles containing DFB. The droplets are routinely in the 200-300 nm range and yield microbubbles on the order of 1-5 μm once vaporized, consistent with ideal gas law expansion predictions. The simple and effective nature of this methodology allows for the development of a variety of different formulations that can be used for imaging, drug and gene delivery, and therapy. This study is the first to our knowledge to demonstrate both a method of generating ADV agents by microbubble condensation and formulation of primarily submicrometer droplets of decafluorobutane that remain stable at physiological temperatures. Finally, activation of DFB nanodroplets is demonstrated using pressures within the FDA guidelines for diagnostic imaging, which may minimize the potential for bioeffects in humans. This methodology offers a new means of developing extravascular contrast agents for diagnostic and therapeutic applications.