5,414 research outputs found
Tabacaleros al grito de guerra: The Mexican tobacco industry and the U.S.-Mexico War
This study analyzes the role of the Mexican tobacco industry during the chaotic years from 1845 to 1847. In nineteenth-century Mexico the tobacco industry was an important financial contributor to Mexican government’s efforts to sustain the war against the United States. Without any significant success, the Mexican government tried to confront and solve the problems limiting the amount of revenues that was expected from the tobacco industry. Regional interests, political factionalism, administrative negligence, and tobacco contraband limited the amount of money the tobacco industry contributed. In spite of all the problems the tobacco industry experienced between 1845 and 1847, the federal government still received significant financial assistance from that industry and the people involved
Universal functions and exactly solvable chaotic systems
A universal differential equation is a nontrivial differential equation the
solutions of which approximate to arbitrary accuracy any continuous function on
any interval of the real line. On the other hand, there has been much interest
in exactly solvable chaotic maps. An important problem is to generalize these
results to continuous systems.
Theoretical analysis would allow us to prove theorems about these systems and
predict new phenomena. In the present paper we discuss the concept of universal
functions and their relevance to the theory of universal differential
equations. We present a connection between universal functions and solutions to
chaotic systems. We will show the statistical independence between and
(when is not equal to zero) and is a solution to
some chaotic systems. We will construct universal functions that behave as
delta-correlated noise. We will construct universal dynamical systems with
truly noisy solutions. We will discuss physically realizable dynamical systems
with universal-like properties.Comment: 12 Pages, 9 figures. Proceedings 1st Meeting IST-IM
A Salmonella protein causes macrophage cell death by inducing autophagy
Salmonella enterica, the causative agent of food poisoning and typhoid fever, induces programmed cell death in macrophages, a process found to be dependent on a type III protein secretion system, and SipB, a protein with membrane fusion activity that is delivered into host cells by this system. When expressed in cultured cells, SipB caused the formation of and localized to unusual multimembrane structures. These structures resembled autophagosomes and contained both mitochondrial and endoplasmic reticulum markers. A mutant form of SipB devoid of membrane fusion activity localized to mitochondria, but did not induce the formation of membrane structures. Upon Salmonella infection of macrophages, SipB was found in mitochondria, which appeared swollen and devoid of christae. Salmonella-infected macrophages exhibited marked accumulation of autophagic vesicles. We propose that Salmonella, through the action of SipB, kills macrophages by disrupting mitochondria, thereby inducing autophagy and cell death
Actinobacillus pleuropneumoniae Possesses an Antiviral Activity against Porcine Reproductive and Respiratory Syndrome Virus
Pigs are often colonized by more than one bacterial and/or viral species during respiratory tract infections. This
phenomenon is known as the porcine respiratory disease complex (PRDC). Actinobacillus pleuropneumoniae (App) and
porcine reproductive and respiratory syndrome virus (PRRSV) are pathogens that are frequently involved in PRDC. The main
objective of this project was to study the in vitro interactions between these two pathogens and the host cells in the
context of mixed infections. To fulfill this objective, PRRSV permissive cell lines such as MARC-145, SJPL, and porcine alveolar
macrophages (PAM) were used. A pre-infection with PRRSV was performed at 0.5 multiplicity of infection (MOI) followed by
an infection with App at 10 MOI. Bacterial adherence and cell death were compared. Results showed that PRRSV preinfection
did not affect bacterial adherence to the cells. PRRSV and App co-infection produced an additive cytotoxicity
effect. Interestingly, a pre-infection of SJPL and PAM cells with App blocked completely PRRSV infection. Incubation of SJPL
and PAM cells with an App cell-free culture supernatant is also sufficient to significantly block PRRSV infection. This antiviral
activity is not due to LPS but rather by small molecular weight, heat-resistant App metabolites (,1 kDa). The antiviral
activity was also observed in SJPL cells infected with swine influenza virus but to a much lower extent compared to PRRSV.
More importantly, the PRRSV antiviral activity of App was also seen with PAM, the cells targeted by the virus in vivo during
infection in pigs. The antiviral activity might be due, at least in part, to the production of interferon c. The use of in vitro
experimental models to study viral and bacterial co-infections will lead to a better understanding of the interactions
between pathogens and their host cells, and could allow the development of novel prophylactic and therapeutic tools
Dopamine D 4 Receptor-Deficient Mice Display Cortical Hyperexcitability
The dopamine D(4) receptor (D(4)R) is predominantly expressed in the frontal cortex (FC), a brain region that receives dense input from midbrain dopamine (DA) neurons and is associated with cognitive and emotional processes. However, the physiological significance of this dopamine receptor subtype has been difficult to explore because of the slow development of D(4)R agonists and antagonists the selectivity and efficacy of which have been rigorously demonstrated in vivo. We have attempted to overcome this limitation by taking a multidimensional approach to the characterization of mice completely deficient in this receptor subtype. Electrophysiological current and voltage-clamp recordings were performed in cortical pyramidal neurons from wild-type and D(4)R-deficient mice. The frequency of spontaneous synaptic activity and the frequency and duration of paroxysmal discharges induced by epileptogenic agents were increased in mutant mice. Enhanced synaptic activity was also observed in brain slices of wild-type mice incubated in the presence of the selective D(4)R antagonist PNU-101387G. Consistent with greater electrophysiological activity, nerve terminal glutamate density associated with asymmetrical synaptic contacts within layer VI of the motor cortex was reduced in mutant neurons. Taken together, these results suggest that the D(4)R can function as an inhibitory modulator of glutamate activity in the FC.Fil: Rubinstein, Marcelo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de Investigaciones en IngenierĂa GenĂ©tica y BiologĂa Molecular "Dr. HĂ©ctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Cepeda, Carlos. University of California at Los Angeles; Estados UnidosFil: Hurst, Raymond S.. University of California at Los Angeles; Estados UnidosFil: Flores Hernandez, Jorge. University of California at Los Angeles; Estados UnidosFil: Ariano, Marjorie A.. The Chicago Medical School; Estados UnidosFil: Falzone, Tomas Luis. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de Investigaciones en IngenierĂa GenĂ©tica y BiologĂa Molecular "Dr. HĂ©ctor N. Torres"; ArgentinaFil: Kozell, Laura B.. Oregon Health Sciences University; Estados UnidosFil: Meshul, Charles K.. Oregon Health Sciences University; Estados UnidosFil: Bunzow, James R.. Oregon Health Sciences University; Estados UnidosFil: Low, Malcolm J.. Oregon Health Sciences University; Estados UnidosFil: Levine, Michael S.. University of California at Los Angeles; Estados UnidosFil: Grandy, David K.. Oregon Health Sciences University; Estados Unido
EvaluaciĂłn de fallas en un transportador de cangilones. Caso de estudio
A failure in the bottom sheet of a bucket conveyor (KZBQ.AUMUND)
during service was investigated. Sheets are
coupled to the chain throught a screw connection; they
operate in variable load scenarios causing fatigue. A
chemical and microstructural analysis was made showing
that sheet was built in steel with 0.15 % of Carbone without
alloying elements that contribute to the refined grain and
resistance increase. Strength calculation, used to
determinate safety factor, consider load system and type
material. Results concluded that geometry and thickness
value do not provide an adequate fatigue resistance
coefficient.Es investigada la falla en las láminas del fondo de un
transportador de cangilones KZB-Q.AUMUND durante su
servicio. Las láminas están acopladas a una cadena a través
de uniones atornilladas y operan bajo un régimen de cargas
variables causándoles fatiga. Se realiza un análisis quĂmico y
microestructural el cual evidencia que las láminas fueron
elaboradas de un acero con 0,15 % de carbono sin
elementos de aleaciĂłn que contribuyan al afinamiento del
grano y al incremento de la resistencia. Se calculan las
tensiones para determinar el coeficiente de seguridad a la
fatiga considerando el sistema de cargas y el material de las
láminas. Los resultados concluyen que la geometrĂa y los
valores de espesor no le proporcionan a las láminas un
adecuado coeficiente de resistencia a la fatiga
Hyperspectral Imaging for Burn Depth Assessment in an Animal Model
Differentiating between superficial and deep-dermal (DD) burns remains challenging. Superficial-dermal burns heal with conservative treatment; DD burns often require excision and skin grafting. Decision of surgical treatment is often delayed until burn depth is definitively identified. This study\u27s aim is to assess the ability of hyperspectral imaging (HSI) to differentiate burn depth.
METHODS: Thermal injury of graded severity was generated on the dorsum of hairless mice with a heated brass rod. Perfusion and oxygenation parameters of injured skin were measured with HSI, a noninvasive method of diffuse reflectance spectroscopy, at 2 minutes, 1, 24, 48 and 72 hours after wounding. Burn depth was measured histologically in 12 mice from each burn group (n = 72) at 72 hours.
RESULTS: Three levels of burn depth were verified histologically: intermediate-dermal (ID), DD, and full-thickness. At 24 hours post injury, total hemoglobin (tHb) increased by 67% and 16% in ID and DD burns, respectively. In contrast, tHb decreased to 36% of its original levels in full-thickness burns. Differences in deoxygenated and tHb among all groups were significant (P \u3c 0.001) at 24 hours post injury.
CONCLUSIONS: HSI was able to differentiate among 3 discrete levels of burn injury. This is likely because of its correlation with skin perfusion: superficial burn injury causes an inflammatory response and increased perfusion to the burn site, whereas deeper burns destroy the dermal microvasculature and a decrease in perfusion follows. This study supports further investigation of HSI in early burn depth assessment
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