Upgrade of an experimental volumetric unit for gas adsorption equilibrium studies

In this work, a volumetric unit previously assembled by the research group was upgraded. This unit revamping was necessary due to the malfunction of the solenoid valves employed in the original experimental setup, which were not sealing the gas properly leading to erroneous adsorption equilibrium measurements. Therefore, the solenoid valves were substituted by manual ball valves. After the volumetric unit improvement its operation was validated. For this purpose, the adsorption equilibrium of carbon dioxide (CO2) at 323K and 0 - 20 bar was measured on two different activated carbon samples, in the of extrudates (ANG6) and of a honeycomb monolith (ACHM). The adsorption equilibrium results were compared with data previously measured by the research group, using a high-pressure microbalance from Rubotherm GmbH (Germany) – gravimetric. The results obtained using both apparatuses are coincident thus validating the good operation of the volumetric unit upgraded in this work. Furthermore, the adsorption equilibrium of CO2 at 303K and 0 - 10 bar on Metal-Organic Frameworks (MOFs) Cu-BTC and Fe-BTC was also studied. The CO2 adsorption equilibrium results for both MOFs were compared with the literature results showing good agreement, which confirms the good quality of the experimental results obtained in the new volumetric unit. Cu-BTC sample showed significantly higher CO2 adsorption capacity when compared with the Fe-BTC sample. The revamping of the volumetric unit included a new valve configuration in order to allow testing an alternative method for the measurement of adsorption equilibrium. This new method was employed to measure the adsorption equilibrium of CO2 on ANG6 and ACHM at 303, 323 and 353K within 0-10 bar. The good quality of the obtained experimental data was testified by comparison with data previously obtained by the research group in a gravimetric apparatus.

Nosocomial infections in a Brazilian neonatal intensive care unit: a 4-year surveillance study

INTRODUCTION: Report the incidence of nosocomial infections, causative microorganisms, risk factors associated with and antimicrobial susceptibility pattern in the NICU of the Uberlândia University Hospital. METHODS: Data were collected through the National Healthcare Safety Network surveillance from January 2006 to December 2009. The patients were followed five times/week from their birth to their discharge or death. RESULTS: The study included 1,443 patients, 209 of these developed NIs, totaling 293 NI episodes, principally bloodstream infections (203; 69.3%) and conjunctivitis (52; 17.7%). Device-associated infection rates were as follows: 17.3 primary bloodstream infections per 1,000 central line-days and 3.2 pneumonias per 1000 ventilator-days. The mortality rate in neonates with NI was 11.9%. Mechanical ventilation, total parenteral nutrition, orogastric tube, previous antibiotic therapy, use of CVC and birth weight of 751-1,000g appeared to be associated with a significantly higher risk of NI (p < 0.05). In multiple logistic regression analysis for NI, mechanical ventilation and the use of CVC were independent risk factors (p < 0.05). Coagulase- negative Staphylococcus (CoNS) (36.5%) and Staphylococcus aureus (23.6%) were the most common etiologic agents isolated from cultures. The incidences of oxacillin-resistant CoNS and S. aureus were 81.8% and 25.3%, respectively. CONCLUSIONS: Frequent surveillance was very important to evaluate the association of these well-known risk factors with NIs and causative organisms, assisting in drawing the attention of health care professionals to this potent cause of morbidity.

40 K Liquid Neon Energy Storage Unit

A thermal Energy Storage Unit (ESU) could be used to attenuate inherent temperature fluctuations of a cold finger, either from a cryocooler working or due to sudden income heat bursts. An ESU directly coupled to the cold source acts as a thermal buffer temporarily increasing its cooling capacity and providing a better thermal stability of the cold finger (“Power Booster mode”). The energy storage units presented here use an enthalpy reservoir based on the high latent heat of the liquid-vapour transition of neon in the temperature range 38 - 44 K to store up to 900 J, and that uses a 6 liters expansion volume at RT in order to work as a closed system. Experimental results in the power booster mode will be described: in this case, the liquid neon cell was directly coupled to the cold finger of the working cryocooler, its volume (12 cm3) allowing it to store 450 J at around 40 K. 10 W heat bursts were applied, leading to liquid evaporation, with quite reduced temperature changes. The liquid neon reservoir can also work as a temporary cold source to be used after stopping the cryocooler, allowing for a vibration-free environment. In this case the enthalpy reservoir implemented (24 cm3) was linked to the cryocooler cold finger through a gas gap heat switch for thermal coupling/decoupling of the cold finger. We will show that, by controlling the enthalpy reservoir’s pressure, 900 J can be stored at a constant temperature of 40 K as in a triple-point ESU.

40 K Neon liquid energy storage unit

Cryocoolers have been progressively replacing the use of the stored cryogens in cryogenic chains used for detector cooling, thanks to their higher and higher reliability. However, the mechanical vibrations, the electromagnetic interferences and the temperature fluctuations inherent to their functioning could reduce the sensor’s sensitivity. In order to minimize this problem, compact thermal energy storage units (ESU) are studied, devices able to store thermal energy without significant temperature increase. These devices can be used as a temporary cold source making it possible to turn the cryocooler OFF providing a proper environment for the sensor. A heat switch is responsible for the thermal decoupling of the ESU from the cryocooler’s temperature that increases when turned OFF. In this work, several prototypes working around 40 K were designed, built and characterized. They consist in a low temperature cell that contains the liquid neon connected to an expansion volume at room temperature for gas storage during the liquid evaporation phase. To turn this system insensitive to the gravity direction, the liquid is retained in the low temperature cell by capillary effect in a porous material. Thanks to pressure regulation of the liquid neon bath, 900 J were stored at 40K. The higher latent heat of the liquid and the inexistence of triple point transitions at 40 K turn the pressure control during the evaporation a versatile and compact alternative to an ESU working at the triple point transitions. A quite compact second prototype ESU directly connected to the cryocooler cold finger was tested as a temperature stabilizer. This device was able to stabilize the cryocooler temperature ((≈ 40K ±1 K) despite sudden heat bursts corresponding to twice the cooling power of the cryocooler. This thesis describes the construction of these devices as well as the tests performed. It is also shown that the thermal model developed to predict the thermal behaviour of these devices, implemented as a software,describes quite well the experimental results. Solutions to improve these devices are also proposed.

40 K neon liquid energy storage unit

Cryocoolers have been progressively replacing the use of the stored cryogens in cryogenic chains used for detector cooling, thanks to their higher and higher reliability. However, the mechanical vibrations, the electromagnetic interferences and the temperature fluctuations inherent to their functioning could reduce the sensor’s sensitivity. In order to minimize this problem, compact thermal energy storage units (ESU) are studied, devices able to store thermal energy without significant temperature increase. These devices can be used as a temporary cold source making it possible to turn the cryocooler OFF providing a proper environment for the sensor. A heat switch is responsible for the thermal decoupling of the ESU from the cryocooler’s temperature that increases when turned OFF. In this work, several prototypes working around 40 K were designed, built and characterized. They consist in a low temperature cell that contains the liquid neon connected to an expansion volume at room temperature for gas storage during the liquid evaporation phase. To turn this system insensitive to the gravity direction, the liquid is retained in the low temperature cell by capillary effect in a porous material. Thanks to pressure regulation of the liquid neon bath, 900 J were stored at 40K. The higher latent heat of the liquid and the inexistence of triple point transitions at 40 K turn the pressure control during the evaporation a versatile and compact alternative to an ESU working at the triple point transitions. A quite compact second prototype ESU directly connected to the cryocooler cold finger was tested as a temperature stabilizer. This device was able to stabilize the cryocooler temperature ((≈ 40K ±1 K) despite sudden heat bursts corresponding to twice the cooling power of the cryocooler. This thesis describes the construction of these devices as well as the tests performed. It is also shown that the thermal model developed to predict the thermal behaviour of these devices,implemented as a software, describes quite well the experimental results. Solutions to improve these devices are also proposed.

Enteric parasites in HIV-1/AIDS-infected patients from a Northwestern São Paulo reference unit in the highly active antiretroviral therapy era

INTRODUCTION: We describe the epidemiology of intestinal parasites in patients from an AIDS reference service in Northeastern São Paulo, Brazil. METHODS: Retrospective evaluation was done for all HIV-1/AIDS-positive patients whose Hospital de Base/São José do Rio Preto laboratorial analysis was positive for enteroparasites after diagnosis of HIV-1 infection, from January 1998 to December 2008. Statistical analysis was performed using the R statistical software version 2.4.1. The level of significance adopted was 5%. RESULTS: The most frequent protozoan was Isospora belli (4.2%), followed by Giardia lamblia (3.5%), Entamoeba coli (2.8%), and Cryptosporidium parvum (0.3%). Ancylostoma duodenale (1.4%) was the most frequently detected helminth, while Taenia saginata and Strongiloides stercoralis were found in 0.7% of the samples. The results showed that diarrhea was significantly associated with giardiasis and isosporiasis. However, no association was observed between CD4+ cell counts, viral load, and the characteristics of any particular parasite. CONCLUSIONS: Our data may be useful for further comparisons with other Brazilian regions and other developing countries. The data may also provide important clues toward improving the understanding, prevention, and control of enteric parasites around the world.

Reduction of catheter-associated bloodstream infections through procedures in newborn babies admitted in a university hospital intensive care unit in Brazil

INTRODUCTION: Catheter-associated bloodstream infection (CA-BSI) is the most common nosocomial infection in neonatal intensive care units. There is evidence that care bundles to reduce CA-BSI are effective in the adult literature. The aim of this study was to reduce CA-BSI in a Brazilian neonatal intensive care unit by means of a care bundle including few strategies or procedures of prevention and control of these infections. METHODS: An intervention designed to reduce CA-BSI with five evidence-based procedures was conducted. RESULTS: A total of sixty-seven (26.7%) CA-BSIs were observed. There were 46 (32%) episodes of culture-proven sepsis in group preintervention (24.1 per 1,000 catheter days [CVC days]). Neonates in the group after implementation of the intervention had 21 (19.6%) episodes of CA-BSI (14.9 per 1,000 CVC days). The incidence of CA-BSI decreased significantly after the intervention from the group preintervention and postintervention (32% to 19.6%, 24.1 per 1,000 CVC days to 14.9 per 1,000 CVC days, p=0.04). In the multiple logistic regression analysis, the use of more than 3 antibiotics and length of stay >8 days were independent risk factors for BSI. CONCLUSIONS: A stepwise introduction of evidence-based intervention and intensive and continuous education of all healthcare workers are effective in reducing CA-BSI.

Relationship between antibiotic consumption, oropharyngeal colonization, and ventilator-associated pneumonia by Staphylococcus aureus in an intensive care unit of a Brazilian teaching hospital

INTRODUCTION: his study evaluated the consumption of major classes of antibiotics, the colonization of the oropharynx of patients on mechanical ventilation, and the risk of ventilator-associated pneumonia (VAP) caused by Staphylococcus aureus in an intensive care unit for adults. METHODS: A case-control study was carried out using colonized patients (cases) by oxacillin-resistant S. aureus (ORSA) and (controls) oxacillin-sensitive S. aureus (OSSA) from May 2009 to August 2010. The occurrence of VAP by S. aureus was also evaluated in the same period. Antibiotic consumption was expressed as the number of defined daily doses (DDD)/1,000 patient-days for glycopeptides, carbapenems, and extended-spectrum cephalosporins. RESULTS: Three hundred forty-six (56.1%) patients underwent mechanical ventilation with a frequency of oropharyngeal colonization of 36.4%, corresponding to 63.5% for ORSA and 36.5% for OSSA. The risk of illness for this organism was significant (p<0.05), regardless of whether colonization/infection was by ORSA or OSSA. The consumption of antibiotics was high, mainly for broad-spectrum cephalosporins (551.26 DDDs/1,000 patient-days). The high density of use of glycopeptides (269.56 DDDs/1,000 patient-days) was related to colonization by ORSA (Pearson r=0.57/p=0.02). Additionally, age >60 years, previous antibiotic therapy, and previous use of carbapenems were statistically significant by multivariate analysis. CONCLUSIONS: There was a significant relationship between the colonization of the oropharyngeal mucosa and the risk of VAP by both phenotypes. The use of glycopeptides was related to colonization by ORSA.

Candida spp. isolated from inpatients, the environment, and health practitioners in the pediatric unit at the Universitary Hospital of the Jundiaí Medical College, state of São Paulo, Brazil

INTRODUCTION: This study aimed to isolate and identify Candida spp. from the environment, health practitioners, and patients with the presumptive diagnosis of candidiasis in the Pediatric Unit at the Universitary Hospital of the Jundiaí Medical College, to verify the production of enzymes regarded as virulence factors, and to determine how susceptible the isolated samples from patients with candidiasis are to antifungal agents. METHODS: Between March and November of 2008 a total of 283 samples were taken randomly from the environment and from the hands of health staff, and samples of all the suspected cases of Candida spp. hospital-acquired infection were collected and selected by the Infection Control Committee. The material was processed and the yeast genus Candida was isolated and identified by physiological, microscopic, and macroscopic attributes. RESULTS: The incidence of Candida spp. in the environment and employees was 19.2%. The most frequent species were C. parapsilosis and C. tropicalis among the workers, C. guilliermondii and C. tropicalis in the air, C. lusitanae on the contact surfaces, and C. tropicalis and C. guilliermondii in the climate control equipment. The college hospital had 320 admissions, of which 13 (4%) presented Candida spp. infections; three of them died, two being victims of a C. tropicalis infection and the remaining one of C. albicans. All the Candida spp. in the isolates evidenced sensitivity to amphotericin B, nystatin, and fluconazole. CONCLUSIONS: The increase in the rate of hospital-acquired infections caused by Candida spp. indicates the need to take larger measures regarding recurrent control of the environment.

Nosocomial infections in a pediatric intensive care unit of a developing country: NHSN surveillance

INTRODUCTION: This study aimed to determine the epidemiology of the three most common nosocomial infections (NI), namely, sepsis, pneumonia, and urinary tract infection (UTI), in a pediatric intensive care unit (PICU) in a developing country and to define the risk factors associated with NI. METHODS: We performed a prospective study on the incidence of NI in a single PICU, between August 2009 and August 2010. Active surveillance by National Healthcare Safety Network (NHSN) was conducted in the unit and children with NI (cases) were compared with a group (matched controls) in a case-control fashion. RESULTS: We analyzed 172 patients; 22.1% had NI, 71.1% of whom acquired it in the unit. The incidence densities of sepsis, pneumonia, and UTI per 1,000 patients/day were 17.9, 11.4, and 4.3, respectively. The most common agents in sepsis were Enterococcus faecalis and Escherichia coli (18% each); Staphylococcus epidermidis was isolated in 13% of cases. In pneumonias Staphylococcus aureus was the most common cause (3.2%), and in UTI the most frequent agents were yeasts (33.3%). The presence of NI was associated with a long period of hospitalization, use of invasive devices (central venous catheter, nasogastric tube), and use of antibiotics. The last two were independent factors for NI. CONCLUSIONS: The incidence of NI acquired in this unit was high and was associated with extrinsic factors.

Food insecurity of HIV/AIDS patients at a unit of outpatient healthcare system in Brasilia, Federal District, Brazil

INTRODUCTION: Food security remains to be one of the world's biggest problems and is found to be related to HIV/AIDS. The objective was to examine food insecurity in HIV/AIDS patients from Brasilia, Brazil. METHODS: Short version of the Food Security Scale was applied to patients with HIV/AIDS. RESULTS: A total of 103 patients participated (65 HIV+ and 38 with AIDS). Food insecurity was found in 33.8% of HIV+ patients and 36.8% of patients with AIDS. A relation between food insecurity and low educational and social levels was established. CONCLUSIONS: Food security should be an important component in HIV/AIDS treatment programs.

Antimicrobial use, incidence, etiology and resistance patterns in bacteria causing ventilator-associated pneumonia in a clinical-surgical intensive care unit

INTRODUCTION : Antimicrobial resistance is an increasing threat in hospitalized patients, and inappropriate empirical antimicrobial therapy is known to adversely affect outcomes in ventilator-associated pneumonia (VAP). The aim of this study was to evaluate antimicrobial usage, incidence, etiology, and antimicrobial resistance trends for prominent nosocomial pathogens causing ventilator-associated pneumonia in a clinical-surgical intensive care unit (ICU). METHODS : Gram-negative bacilli and Staphylococcus aureus causing VAP, as well as their antimicrobial resistance patterns and data on consumption (defined daily dose [DDD] per 1,000 patient days) of glycopeptides, extended-spectrum cephalosporins, and carbapenems in the unit were evaluated in two different periods (A and B). RESULTS: Antimicrobial use was high, mainly of broad-spectrum cephalosporins, with a significant increase in the consumption of glycopeptides (p < 0.0001) and carbapenems (p < 0.007) in period B. For Acinetobacter baumannii and members of the Enterobacteriaceae family, 5.27- and 3.06-fold increases in VAPs, respectively, were noted, and a significant increase in resistance rates was found for imipenem-resistant A. baumannii (p = 0.003) and third-generation cephalosporins-resistant Enterobacteriaceae (p = 0.01) isolates in this same period. CONCLUSIONS: Our results suggest that there is a link between antibiotics usage at institutional levels and resistant bacteria. The use of carbapenems was related to the high rate of resistance in A. baumannii and therefore a high consumption of imipenem/meropenem could play a major role in selective pressure exerted by antibiotics in A. baumannii strains.

Demographic determinants of survival of people living with HIV attending an outpatient reference unit in the city of Três Lagoas, state of Mato Grosso do Sul, Brazil, in the period 1984-2009

INTRODUCTION: While the incidence of HIV infection and AIDS is increasing in small Brazilian cities, epidemiological studies are often conducted in large urban centers. METHODS: Our group conducted a retrospective analysis of survival determinants among 358 patients who attended a reference unit in a small city. RESULTS: Death risk was lower among men that had sex with men, patients with an HIV-seropositive partner, and those admitted after highly active antiretroviral therapy (HAART) was available. CONCLUSIONS: The study documents the striking beneficial effect of HAART. The finding of other groups with improved survival may aid in the development of programmatic strategies.

Acute kidney injury in a tropical country: a cohort study of 253 patients in an infectious diseases intensive care unit

Introduction: Acute kidney injury (AKI) is a frequent and potentially fatal complication in infectious diseases. The aim of this study was to investigate the clinical aspects of AKI associated with infectious diseases and the factors associated with mortality. Methods: This retrospective study was conducted in patients with AKI who were admitted to the intensive care unit (ICU) of a tertiary infectious diseases hospital from January 2003 to January 2012. The major underlying diseases and clinical and laboratory findings were evaluated. Results: A total of 253 cases were included. The mean age was 46±16 years, and 72% of the patients were male. The main diseases were human immunodeficiency virus (HIV) infection, HIV/acquired immunodeficiency syndrome (AIDS) (30%), tuberculosis (12%), leptospirosis (11%) and dengue (4%). Dialysis was performed in 70 cases (27.6%). The patients were classified as risk (4.4%), injury (63.6%) or failure (32%). The time between AKI diagnosis and dialysis was 3.6±4.7 days. Oliguria was observed in 112 cases (45.7%). The Acute Physiology and Chronic Health Evaluation (APACHE) II scores were higher in patients with HIV/AIDS (57±20, p-value=0.01) and dengue (68±11, p-value=0.01). Death occurred in 159 cases (62.8%). Mortality was higher in patients with HIV/AIDS (76.6%, p-value=0.02). A multivariate analysis identified the following independent risk factors for death: oliguria, metabolic acidosis, sepsis, hypovolemia, the need for vasoactive drugs, the need for mechanical ventilation and the APACHE II score. Conclusions: AKI is a common complication in infectious diseases, with high mortality. Mortality was higher in patients with HIV/AIDS, most likely due to the severity of immunosuppression and opportunistic diseases.

Association between the degree of physical impairment from leprosy and dependence in activities of daily living among the elderly in a health unit in the State of Minas Gerais

Introduction In addition to the common alterations and diseases inherent in the aging process, elderly persons with a history of leprosy are particularly vulnerable to dependence because of disease-related impairments. Objective determine whether physical impairment from leprosy is associated with dependence among the elderly. Methods An analytical cross-sectional study of elderly individuals with a history of leprosy and no signs of cognitive impairment was conducted using a database from a former leprosy colony-hospital. The patients were evaluated for dependence in the basic activities of daily living (BADL) and instrumental activities of daily living (IADL), respectively) and subjected to standard leprosy physical disability grading. Subsequently, descriptive and univariate analyses were conducted, the latter using Pearson's chi-squared test. Results A total of 186 elderly persons were included in the study. Of these individuals, 53.8% were women, 49.5% were older than 75 years of age, 93% had four or less years of formal education, 24.2% lived in an institution for the long-term care of the elderly (ILTC), and 18.3% had lower limb amputations. Among those evaluated, 79.8% had visible physical impairments from leprosy (grade 2), 83.3% were independent in BADL, and 10.2% were independent in IADL. There was a higher impairment grade among those patients who were IADL dependent (p=0.038). Conclusion s: The leprosy physical impairment grade is associated with dependence for IADL, creating the need for greater social support and systematic monitoring by a multidisciplinary team. The results highlight the importance of early diagnosis and treatment of leprosy to prevent physical impairment and dependence in later years.