Unveiling the Inhomogeneous Nature of Strong Field Ionization in Extended Systems

Intense light-induced fragmentation of spherical clusters produces highly energetic ions with characteristic spatial distributions. By subjecting argon clusters to a wavelength tunable laser, we show that ion emission energy and anisotropy can be controlled through the wavelength-isotropic and energetic for shorter wavelengths and increasingly anisotropic at longer wavelengths. The anisotropic part of the energy spectrum, consisting of multiply charged high-energy ions, is considerably more prominent at longer wavelengths. Classical molecular dynamics simulations reveal that cluster ionization occurs inhomogeneously producing a columnlike charge distribution along the laser polarization direction. This previously unknown distribution results from the dipole response of the neutral cluster which creates an enhanced field at the surface, preferentially triggering ionization at the poles. The subsequently formed nanoplasma provides an additional wavelength-dependent ionization mechanism through collisional ionization, efficiently homogenizing the system only at short wavelengths close to resonance. Our results open the door to studying polarization induced effects in nanostructures and complex molecules and provide a missing piece in our understanding of anisotropic ion emission.

Discovery of Novel UDP-N-Acetylglucosamine Acyltransferase (LpxA) Inhibitors with Activity against Pseudomonas aeruginosa

This study describes a novel series of UDP-N-acetylglucosamine acyltransferase (LpxA) inhibitors that was identified through affinity-mediated selection from a DNA-encoded compound library. The original hit was a selective inhibitor of Pseudomonas aeruginosa LpxA with no activity against Escherichia coli LpxA. The biochemical potency of the series was optimized through an X-ray crystallography-supported medicinal chemistry program, resulting in compounds with nanomolar activity against P. aeruginosa LpxA (best half-maximal inhibitory concentration (IC₅₀) <5 nM) and cellular activity against P. aeruginosa (best minimal inhibitory concentration (MIC) of 4 μg/mL). Lack of activity against E. coli was maintained (IC₅₀ > 20 μM and MIC > 128 μg/mL). The mode of action of analogues was confirmed through genetic analyses. As expected, compounds were active against multidrug-resistant isolates. Further optimization of pharmacokinetics is needed before efficacy studies in mouse infection models can be attempted. To our knowledge, this is the first reported LpxA inhibitor series with selective activity against P. aeruginosa.

Penile Melanoma In Situ: Long Term Follow Up

Penile melanoma in situ is extremely rare. Various treatments have been reported with good success, however follow up is generally limited to 1 year or less. The optimal treatment regimen, pattern of disease progression and utility of sentinel lymph node biopsy are not established. We provide the longest reported follow up for penile malignant melanoma in-situ, highlighting a long-term pattern of recurrence and a route of progression which does not follow more reliable patterns of lymphatic spread known to penile squamous cell carcinoma. A cautious approach should be taken for organ-sparing approaches along with proper patient counseling and close, long-term follow-up.

Disentangling Spectral Phases of Interfering Autoionizing States from Attosecond Interferometric Measurements

We have determined spectral phases of Ne autoionizing states from extreme ultraviolet and midinfrared attosecond interferometric measurements and ab initio full-electron time-dependent theoretical calculations in an energy interval where several of these states are coherently populated. The retrieved phases exhibit a complex behavior as a function of photon energy, which is the consequence of the interference between paths involving various resonances. In spite of this complexity, we show that phases for individual resonances can still be obtained from experiment by using an extension of the Fano model of atomic resonances. As simultaneous excitation of several resonances is a common scenario in many-electron systems, the present work paves the way to reconstruct electron wave packets coherently generated by attosecond pulses in systems larger than helium.

Implementation of safe sleep practices in the neonatal intensive care unit

OBJECTIVE

To increase the percentage of eligible infants engaging in safe sleep practices (SSP) in two level III neonatal intensive care units (NICUs) in the Boston, Massachusetts area.

STUDY DESIGN

On the basis of eligibility criteria (⩾34 weeks or ⩾1800 g without acute medical conditions), all infants were eligible for two sleep practices: SSP or NICU therapeutic positioning (NTP) depending on their gestational age, weight, clinical illness and need for therapeutic interventions. Compliance with SSP was defined as: (1) supine positioning, (2) in a flat crib with no incline, (3) without positioning devices and (4) without toys, comforters or fluffy blankets. NTP comprised usual NICU care. Nursing education was comprised of a web-based learning module and in-person teaching sessions with a study team member. Double-sided crib cards (SSP one side and NTP on the other) were attached to the bedside of every infant. Pre- and postintervention audits of all infants were carried out at both study sites. We compared compliance across all time points using generalized estimating equations to account for correlated data (SAS v9.3, Cary, NC, USA).

RESULT

Of 755 cases, 395 (52.3%) were assessed to be eligible for SSP. From the pre- to post-intervention period, there was a significant improvement in overall compliance with SSP (25.9 to 79.7%; P-value<0.001). Adherence to each component of SSP also improved significantly following the intervention.

CONCLUSION

Safe infant sleep practices can be integrated into the routine care of preterm infants in the NICU. Modeling SSP to families far in advance of hospital discharge may improve adherence to SSP at home and reduce the risk of sleep-related morbidity and mortality in this vulnerable population of infants.

Mature cystic teratoma of both the fallopian tube and contralateral ovary: a case report

Intratubal teratoma is a very rare condition. The authors believe to present the first case of a completely intratubal mature cystic teratoma with a contralateral intraovarian teratoma. Preoperative ultrasound examination allowed the intraoperative diagnosis of this rare condition, hence allowing appropriate surgical management.

MATERIALS AND METHODS

A 19-year-old woman presented with a history of pelvic pain and severe dysmenorrhea. Ultrasound examination initially suggested bilateral ovarian dermoids. Upon laparoscopy, the distal left fallopian tube was obstructed and contained an inflammatory mass adhered to the rectosigmoid. The left ovary was entirely normal. A contralateral intraovarian dermoid was also identified.

CONCLUSION

Although rare, when an intratubal mass is identified, consideration of intratubal dermoid should be given. Preoperative ultrasound can be of critical importance to the intraoperative diagnosis.

Dual channel planar waveguide surface plasmon resonance biosensor for an aqueous environment

A theoretical study on a dual channel planar waveguide surface plasmon biosensor is presented in this paper. The proposed device consists of a planar waveguide with two active regions. It has been demonstrated that the proposed waveguide sensor can be configured to operate in either multi analyte or self referencing mode. The channel discriminative property of the device is investigated using an eigenmode solver with perfectly matched layers (PML).

Ablation of AMP-activated protein kinase alpha1 and alpha2 from mouse pancreatic beta cells and RIP2.Cre neurons suppresses insulin release in vivo

AIMS/HYPOTHESIS

AMP-activated protein kinase (AMPK) is an evolutionarily conserved enzyme and a target of glucose-lowering agents, including metformin. However, the precise role or roles of the enzyme in controlling insulin secretion remain uncertain.

METHODS

The catalytic alpha1 and alpha2 subunits of AMPK were ablated selectively in mouse pancreatic beta cells and hypothalamic neurons by breeding Ampkalpha1 [also known as Prkaa1]-knockout mice, bearing floxed Ampkalpha2 [also known as Prkaa2] alleles (Ampkalpha1 ( -/- ),alpha2( fl/fl ),), with mice expressing Cre recombinase under the rat insulin promoter (RIP2). RIP2 was used to express constitutively activated AMPK selectively in beta cells in transgenic mice. Food intake, body weight and urinary catecholamines were measured using metabolic cages. Glucose and insulin tolerance were determined after intraperitoneal injection. Beta cell mass and morphology were analysed by optical projection tomography and confocal immunofluorescence microscopy, respectively. Granule docking, insulin secretion, membrane potential and intracellular free Ca(2+) were measured with standard techniques.

RESULTS

Trigenic Ampkalpha1 ( -/- ),alpha2( fl/fl ) expressing Cre recombinase and lacking both AMPKalpha subunits in the beta cell, displayed normal body weight and increased insulin sensitivity, but were profoundly insulin-deficient. Secreted catecholamine levels were unchanged. Total beta cell mass was unaltered, while mean islet and beta cell volume were reduced. AMPK-deficient beta cells displayed normal glucose-induced changes in membrane potential and intracellular free Ca(2+), while granule docking and insulin secretion were enhanced. Conversely, betaAMPK transgenic mice were glucose-intolerant and displayed defective insulin secretion.

CONCLUSIONS/INTERPRETATION

Inhibition of AMPK activity within the beta cell is necessary, but not sufficient for stimulation of insulin secretion by glucose to occur. AMPK activation in extrapancreatic RIP2.Cre-expressing cells might also influence insulin secretion in vivo.

Design and optimization of a novel surface plasmon resonance biosensor based on Otto configuration

A theoretical study on a novel planar waveguide surface Plasmon Biosensor is presented in this paper. The proposed biosensor has a configuration similar to the Otto excitation mechanism for surface Plasmon polaritons. The performance of the device with respect to key system parameters such as gap-width and device length is investigated using an eigenmode solver with perfectly matched layers (PML). Device resolution of 2.3 x 10(-6) RIU has been demonstrated for an aqueous analyte.

Dental nursing education and the introduction of technology-assisted learning

The aim of this paper is to explore the profile of dental nursing students in the National Dental Nurse Training Programme of Ireland and their adjustment to a technology-assisted learning environment. Evaluation by students of the course and their reactions to the course were analysed. Dental nurses must possess the skills and knowledge to proficiently function in the modern day dental surgery. The implementation of a dental nurse programme that is heavily reliant on technology has started to create a group of dental nurses equipped with basic skills to access and retrieve information over a lifetime. However, the transition to a technology-assisted learning environment including online learning activities requires adaptation and expertise by educators and students alike. Careful evaluation and stakeholder feedback is imperative in the creation and maintaining of a quality programme. In conclusion, the students in this study responded well to the transition to a technology-based learning environment. Furthermore, the findings of this study suggest that the use of an online environment is an effective and stimulating learning environment for the students of a dental nurse programme; however, familiarity skills and knowledge of information technology is a prerequisite for success.

Effect of high-fat diet on glucose homeostasis and gene expression in glucokinase knockout mice

AIM

We have generated a heterozygous glucokinase knockout mouse (gk(del/wt)), upon which we investigated the effect of high-fat diet (HFD) with respect to metabolic control and both hepatic and beta-cell gene expression. We also investigated the in vitro efficacy of a glucokinase activator (GKA) on glucose-stimulated insulin secretion (GSIS) in gk(del/wt)mouse islets.

METHODS

Male gk(del/wt)and gk(wt/wt)mice were grouped (n = 8-10) at 10 weeks of age and fed HFD or chow diet (CD) for 10 weeks. Multiple parameters including blood glucose, plasma insulin and glucose tolerance were assessed. Further animal groups were used for in vitro GSIS and islet and liver gene expression analysis.

RESULTS AND CONCLUSIONS

gk(del/wt)mice showed early-onset persistent hyperglycaemia, raised glycated haemoglobin levels, impaired GSIS and glucose tolerance but no change in plasma cholesterol, non-esterified fatty acids or triglyceride levels. After HFD feeding, insulin levels of gk(del/wt)mice were less than half that of gk(wt/wt)mice, although they were equivalent to gk(wt/wt)mice on CD. While gk(wt/wt)mice maintained moderate hyperglycaemia, gk(del/wt)mice became overtly diabetic, with worsened glucose tolerance. A GKA (GKA50) increased GSIS, at 10 mM glucose, in gk(del/wt)mice to an extent at least as great as that seen in gk(wt/wt)mice on both CD and HFD. gk(del/wt)mice showed only a small number of changes in gene expression compared with gk(wt/wt)mice. We propose the high fat-fed gk(del/wt)mouse as a model of type 2 diabetes and report retained efficacy of a GKA on in vitro GSIS.

Combined RAF1 protein expression and p53 mutational status provides a strong predictor of cellular radiosensitivity

The tumour suppressor gene, p53, and genes coding for positive signal transduction factors can influence transit through cell-cycle checkpoints and modulate radiosensitivity. Here we examine the effects of RAF1 protein on the rate of exit from a G2/M block induced by gamma-irradiation in relation to intrinsic cellular radiosensitivity in human cell lines expressing wild-type p53 (wtp53) protein as compared to mutant p53 (mutp53) protein. Cell lines which expressed mutp53 protein were all relatively radioresistant and exhibited no relationship between RAF1 protein and cellular radiosensitivity. Cell lines expressing wtp53 protein, however, showed a strong relationship between RAF1 protein levels and the radiosensitivity parameter SF2. In addition, when post-irradiation perturbation of G2/M transit was compared using the parameter T50 (time after the peak of G2/M delay at which 50% of the cells had exited from a block induced by 2 Gy of irradiation), RAF1 was related to T50 in wtp53, but not mutp53, cell lines. Cell lines which expressed wtp53 protein and high levels of RAF1 had shorter T50s and were also more radiosensitive. These results suggest a cooperative role for wtp53 and RAF1 protein in determining cellular radiosensitivity in human cells, which involves control of the G2/M checkpoint.

Seroprevalence of Toxoplasma gondii infection in sheep and alpacas (Llama pacos) in Chile

Serum samples from 408 sheep from different regions of Chile and 447 alpacas (Llama pacos) from the north of the country were tested for Toxoplasma gondii antibodies. The indirect haemagglutination test (IHAT) was used in both species and the indirect immunofluorescence test (IIFT) was also used on the sheep samples in order to compare the performance of the tests in that species. In both tests, titers > or = 1:16 were considered diagnostically significant. Sera from 49 sheep (12%) were positive to T. gondii antibodies by the IHAT. When using the IIFT, 114 sheep sera (28%) were positive. The different results obtained in sheep sera between the tests were significant (p < 0.0001). No differences were observed between geographical locations or sex of the sampled sheep regarding serological detection of T. gondii antibodies in sheep. As expected, adult sheep showed higher T. gondii reactivity than young sheep (p = 0.0008). The corrected prevalence of toxoplasmosis in alpaca was 16.3% (32 positive out of 447). The rather low prevalence in alpacas may be associated with their extensive management as well as the extreme climatic conditions of The Andes which apparently would not be favorable for the transmission of the parasite.

Immunodiagnosis of fasciolosis in horses and pigs using western blots

Crude and partially purified somatic (S) and excretory-secretory (ES) antigens of Fasciola hepatica were subjected to Western blot analysis in order to identify polypeptides that would enable specific and sensitive immunodiagnosis of horse and pig fasciolosis to be undertaken. Sera from 20 horses and 20 pigs with natural infections of F. hepatica and the same number of uninfected hosts of each species were tested, together with sera from 2 pigs with Cysticercus cellulosae infections. Using crude S antigens, sera from infected horses and pigs reacted specifically with a wide range of polypeptides of 14-19, 22-30, 35-37 and 42 kDa. Likewise, specific reactivity between polypeptides of 14-17, 22-30 and 40-42 kDa in crude ES antigens and sera from infected horses and pigs was obtained. Against the criteria of high sensitivity and specificity, the 22-30-kDa polypeptides would appear to be the most suitable candidate antigens for use in the immunodiagnosis of fasciolosis in horses and pigs.

Potentiometric Titration Methods for the Determination of Sodium Chloride in Certifiable Water-Soluble Colors: Collaborative Study

In a collaborative study, 7 laboratories successfully analyzed 8 different samples, in duplicate, by a manual potentiometric titration method. These same samples were used by 7 different laboratories in a concurrent collaborative study of the automated potentiometric titration method. The samples are dissolved in water and acidified, and soluble chloride is determined by titration with silver nitrate to the potentiometric end point. The methods are applicable to all water-soluble certifiable colors except D&C Red No. 19, at levels &gt;0.03% sodium chloride, although there is a positive error at very low levels for the automated titration. In halogenated fluoresceins, any iodide or bromide is determined as sodium chloride, but the maximum amount normally present is equivalent to &lt;0.2% sodium chloride. The sodium chloride content of the collaborative samples ranged from 0.04 to 18.2% for the manual method, and from 0.11 to 18.1% for the automated method. In general, except at very low sodium chloride levels, the precision of the automated method was good, although not as high as that for the manual method; single determination coefficients of variation ranged from 1.5 to 13.5% for the former, and from 1.2 to 2.7% for the latter. Recovery of 0.45% added sodium chloride ranged from 62 to 96%, and for 4.5% added sodium chloride it varied from 94 to 99% by the automated method. Recoveries ranged from 96 to 104% for 0,45% added sodium chloride and from 98 to 102% for 4.5% added sodium chloride by the manual method. The coefficient of correlation of the sample means for the manual and the automated methods was 0.9999%. The methods have been adopted as official first action.