On the dynamics of population inversion for 3 μm Er3+lasers

A generalized model for 3-μm (⁴I_11/2 →⁴I_13/2)Er lasers is proposed. The essential energy transfer processes present in the single-doped Er ³⁺ systems (up-conversion from ⁴I_13/2, up-conversion from ⁴ I_11/2, cross-relaxation from ⁴S _3/2), as well as those present in Cr³⁺ codoped Er ³⁺ systems, are taken into account. In the frame of this model, the main features of 3 μm Er³⁺ lasers, such as long pulse or CW operation, the change of emission wavelength as a function of pumping conditions, and the effects of codoping with Ho³⁺ or Tm³⁺ ions, are explained     

Interaction phenomena in double-symmetrical rolled compressed members

The paper deals with interaction phenomena concerning double-symmetrical rolled compressed members.

Using an original model of analysis based upon a second-order analysis, a formula for the determination of the ultimate force P_u is given. This formula is valid in the elastic range.     

Herniated lumbar intervertebral discs spontaneously produce matrix metalloproteinases, nitric oxide, interleukin-6, and prostaglandin E2

OBJECTIVE: To estimate the prevalence and social correlates of cardiovascular disease. DESIGN: Population-based cross-sectional survey. Survey data were obtained through a standardized home interview and a clinic visit by trained nurses. The question sequence of the London School of Hygiene (the Rose Questionnaire) was used to identify the presence of definite angina, possible infarction, definite infarction, intermittent claudication and stroke. SETTING: Eight urban communities and rural areas in Saskatchewan in 1990. PARTICIPANTS: A probability sample of 2167 noninstitutionalized men and women aged 18 to 74 years who participated in the Saskatchewan Heart Health Survey. MAIN OUTCOME MEASURES: Prevalence of cardiovascular diseases. RESULTS: Among men, the prevalence of definite angina increased gradually with age from 1.7% (95% CI 0.6% to 2.7%) in the 18 to 34 year group, 3.8% (1.3% to 6.0%) in the 35 to 54 year group to 4.8% (2.8% to 8.3%) in the 55 to 74 year group, while the prevalence among women ranged from 2.5% (1.2 to 3.7%), 4.0% (1.6% to 6.5%) to 7.1% (5.1% to 11.6%) in these same age groups. The prevalence of possible angina, definite infarction, possible infarction and intermittent claudication increased with age as well, being higher in men than in women. Generally, the conditions were more prevalent among those with less education, lower income and those who were unemployed. CONCLUSIONS: These findings indicate that there is sociodemographic inequality in the prevalence of these manifestations of cardiovascular disease, and there is a need for in-depth qualitative research into causal factors in this relationship and for targeted programs of health promotion.     

Downregulation of polo-like kinase correlates with loss of proliferative ability of cardiac myocytes

Cardiac myocytes rapidly increase the cell number during the fetal and early neonatal period, but they lose their proliferative ability soon after birth. To understand the mechanism of how cardiac myocytes exit from the cell cycle, we examined the role of a newly identified serine/threonine kinase, polo-like kinase (Plk), in the process of proliferation of cardiac myocytes. Northern blot analysis revealed that Plk gene was abundantly expressed in cardiac myocytes and non-myocytes of fetal and neonatal rats but not in cardiocytes of adult rats. Western blot analysis showed that Plk protein was also detected only in fetal and neonatal hearts. During the early stage of cardiac differentiation. Plk expression was well correlated with the proliferative ability of cardiocytes. Plk mRNA was most abundant in undifferentiated embryonic stem (ES) cells and the mRNA levels decreased along with cardiac differentiation in the developing ES cell system. Once serum was deprived from the culture media, expression levels of Plk were markedly decreased and DNA was not synthesized in both cardiac myocytes and non-myocytes of neonatal rats. Re-addition of serum stimulated Plk gene expression and DNA synthesis in non-myocytes but not in cardiomyocytes. All these results taken together with the critical role of Plk in DNA synthesis in many cell types suggest that downregulation of Plk is important for the permanent withdrawal of cardiomyocytes from the cell cycle.     

Structure of interleukin 16 resembles a PDZ domain with an occluded peptide binding site

BACKGROUND: Cervical lymphadenectomy to remove metastatic disease in level II encompasses lymph nodes associated with the upper third of the internal jugular vein and the adjacent spinal accessory nerve (SAN). Conservative neck dissection (ND) preserves these structures but requires manipulation of the SAN to remove tissue located in the posterosuperior aspect of level II. Limiting the dissection to the nodal group anterior to the SAN may reduce operating time and limit injury to it without compromising the removal of lymph nodes at risk for involvement with cancer. METHODS: Seventy-one patients with squamous cell carcinoma of the head and neck treated with cervical lymphadenectomy at two separate institutions were prospectively evaluated. One hundred two neck dissection specimens were histologically analyzed for number of lymph nodes present and number involved with cancer. At the time of surgery, level II was separated into the supraspinal accessory nerve component (IIa) and the component anterior to the SAN (IIb). Nodal involvement in level II was analyzed according to characteristics of the cancer at the primary site as well as nodal involvement of other levels. RESULTS: Neck dissections were most commonly done for cancer of the oral cavity (n = 33), followed in frequency by the larynx (n = 17), oropharynx (n = 7), skin of face (n = 4), unknown primary (n = 4), and other sites (n = 6). Eighty NDs were selective and 22 were either radical or modified radical NDs. Pathologic staging of the neck specimen was most commonly N0 (n = 61), followed in frequency by N1 (n= 17), N2 (n= 11), and N3 (n= 11). Data were unclear for two specimens. Level IIb contained an average of 6.9 nodes and the IIa component contained an average of 4.2 nodes. Level II contained metastatic disease in 31 of 39 node positive specimens (79%). Level IIa was involved with cancer in four cases, all of which were preoperatively staged N2 or greater. CONCLUSIONS: The additional time required and morbidity associated with dissection of the supraspinal accessory nerve component of level II may not be necessary when performing elective ND. More research with larger numbers of patients, long-term follow-up, and meticulous tissue analysis is needed to permit conclusions as to where to draw the line in determining extent of cervical lymphadenectomy.     

Integral aspect of transistor differential conductances

There is experimental evidence that several transistor types in specified regimes have I–V characteristics with identical features, namely: constant differential conductances; translation symmetry.Therefore, they might admit similar approaches. We intend to describe them analytically using integral expressions of the current, in order to connect the differential conductances with the boundary values rather than with the detailed charge and field distributions.     

Learning and generalization deficits in patients with memory impairments due to anterior communicating artery aneurysm rupture or hypoxic brain injury.

[Correction Notice: An erratum for this article was reported in Vol 22(6) of Neuropsychology (see record 2008-15268-012). Author Ramona O. Hopkins's name was misspelled as Romona O. Hopkins.] Human anterograde amnesia can result from a variety of etiologies, including hypoxic brain injury and anterior communicating artery (ACoA) aneurysm rupture. Although each etiology can cause a similarly severe disruption in declarative memory for verbal and visual material, there may be differences in incrementally acquired, feedback-based learning, as well as generalization. Here, 6 individuals who survived hypoxic brain injury, 7 individuals who survived ACoA aneurysm rupture, and 13 matched controls were tested on 2 tasks that included a feedback-based learning phase followed by a transfer phase in which familiar information is presented in new ways. In both tasks, the ACoA group was slow on initial learning, but those patients who completed the learning phase went on to transfer as well as controls. In the hypoxic group, 1 patient failed to complete either task; the remaining hypoxic group did not differ from controls during learning of either task, but was impaired on transfer. These results highlight a difference in feedback-based learning in 2 amnesic etiologies, despite similar levels of declarative memory impairment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Learning and generalization deficits in patients with memory impairments due to anterior communicating artery aneurysm rupture or hypoxic brain injury": Correction.

Reports an error in "Learning and generalization deficits in patients with memory impairments due to anterior communicating artery aneurysm rupture or hypoxic brain injury" by Catherine E. Myers, Ramona O. Hopkins, John DeLuca, Nancy B. Moore, Leo J. Wolansky, Jennifer M. Sumner and Mark A. Gluck (Neuropsychology, 2008[Sep], Vol 22[5], 681-686). Author Ramona O. Hopkins's name was misspelled as Romona O. Hopkins. (The following abstract of the original article appeared in record 2008-11707-013.) Human anterograde amnesia can result from a variety of etiologies, including hypoxic brain injury and anterior communicating artery (ACoA) aneurysm rupture. Although each etiology can cause a similarly severe disruption in declarative memory for verbal and visual material, there may be differences in incrementally acquired, feedback-based learning, as well as generalization. Here, 6 individuals who survived hypoxic brain injury, 7 individuals who survived ACoA aneurysm rupture, and 13 matched controls were tested on 2 tasks that included a feedback-based learning phase followed by a transfer phase in which familiar information is presented in new ways. In both tasks, the ACoA group was slow on initial learning, but those patients who completed the learning phase went on to transfer as well as controls. In the hypoxic group, 1 patient failed to complete either task; the remaining hypoxic group did not differ from controls during learning of either task, but was impaired on transfer. These results highlight a difference in feedback-based learning in 2 amnesic etiologies, despite similar levels of declarative memory impairment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Applications of Nanomaterials in Cell Stem Therapies and the Onset of Nanomedicine

Stem cells hold enormous potential in the treatment of diseases such as diabetes, arthritis, cirrhosis, spinal cord injury, and Alzheimer's disease, due to their unique ability to differentiate into various cell lines and tissues and integrate seamlessly into damaged or diseased tissue. The use of nanoparticles as bioactive molecules is still considered a nascent science, but their unique physical and chemical properties hold great hopes for drug delivery, cancer targeting, and bioimaging. There is active worldwide ongoing research to generate advanced therapeutic compounds for incurable diseases, combining the unique properties of nanomaterials and stem cells. The present review will cover emerging areas of nanotechnology applications in stem cell therapy, one of the next frontiers of medical science.