Low-loss Kagome hollow-core fibers operating from the near- to the mid-IR.

We report the fabrication and characterization of Kagome hollow-core antiresonant fibers, which combine low attenuation (as measured at ∼30 cm bend diameter) with a wide operating bandwidth and high modal purity. Record low attenuation values are reported: 12.3 dB/km, 13.9 dB/km, and 9.6 dB/km in three different fibers optimized for operation at 1 µm, 1.55 µm, and 2.5 µm, respectively. These fibers are excellent candidates for ultra-high power delivery at key laser wavelengths including 1.064 µm and 2.94 µm, as well as for applications in gas-based sensing and nonlinear optics.

Low dose of lidocaine: comparison of 15 with 20 mg/ml with dextrose for spinal anesthesia in lithotomy position and ambulatory surgery.

BACKGROUND: Spinal anesthesia with the local anesthetic lidocaine has come under scrutiny because it is associated with transient neurologic symptoms (TNS). Although TNS is not associated with either lidocaine concentration or dose, its incidence has never been examined with very small doses of hyperbaric spinal lidocaine in patients in the lithotomy position. We designed this study prospectively to compare the efficacy of low-dose 15 mg/ml with low-dose 20 mg/ml hyperbaric lidocaine in patients undergoing elective outpatient surgery in the lithotomy position. METHODS: A total of 100 patients were randomized to receive either 30 mg of 15 mg/ml or the same dose of 20 mg/ml hyperbaric lidocaine. Lidocaine density at 37 degrees C is 1.0241 g/ml for the 15 mg/ml and 1.0260 g/ml for the 20 mg/ml solution. Patients were examined for motor block, sensory block, and block duration. Patients were contacted at 24, 48 and 72 h and questioned about their perceptions of pain after the spinal anesthesia with specific questions designed to diagnose TNS. RESULTS: The spread of analgesia was the same with both solutions of lidocaine. Motor block was incomplete in all patients in both groups. TNS were not observed when low doses of both solutions of lidocaine with dextrose were used in these ambulatory patients in the lithotomy position. CONCLUSION: Hyperbaric lidocaine results in rapid recovery from sensory block and motor blockade. It may have advantages for patients in a day-case setting. No patients complained of TNS after discharge.

Selective sensory spinal anaesthesia with hypobaric lidocaine for anorectal surgery.

BACKGROUND: Lidocaine has been used for spinal anaesthesia since 1948, seemingly without causing concern until recently. This study aimed at evaluating the feasibility of performing anorectal surgery in outpatient settings with low hypobaric lidocaine doses. METHODS: Three groups of 50 patients, physical status ASA I-II, undergoing anorectal surgical procedures in a prone jack-knife position, received 3 ml (18 mg), 4 ml (24 mg) or 5 ml (30 mg) of hypobaric 0.6% lidocaine. Sensory and motor blockade, time until first urination, ambulation, complications and the need for analgesics were evaluated. Patients were followed until the third post-operative day. RESULTS: Adequate sensory block was obtained in all patients. Blockade was significantly lower in Group 1. The level at 15 min was L(1) with 3 ml, T(11) with 4 ml and T(10) with 5 ml. Only 24 patients presented a moderate motor block. There was no hypotension, nausea or vomiting, urine retention, transitory neurological symptom or post-dural puncture headache in any patients. There was one case of bradycardia with 4 ml and two cases with 5 ml. CONCLUSIONS: Hypobaric lidocaine predominantly provided a sensory block after injection in the prone jack-knife position. The smallest dose (3 ml=18 mg) provides sufficient analgesia with a lesser dispersion and a shorter duration. The major advantages were haemodynamic stability and a high degree of patient satisfaction.

Mid-IR Hollow-core microstructured fiber drawn from a 3D printed PETG preform.

Mid-infrared (mid-IR) optical fibers have long attracted great interest due to their wide range of applications in security, biology and chemical sensing. Traditionally, research was directed towards materials with low absorption in the mid-IR region, such as chalcogenides, which are difficult to manipulate and often contain highly toxic elements. In this paper, we demonstrate a Polyethylene Terephthalate Glycol (PETG) hollow-core fiber (HCF) with guiding properties in the mid-IR. Guiding is provided by the fiber geometry, as PETG exhibits a material attenuation 2 orders of magnitude larger than the HCF propagation loss. The structured plastic fiber preforms were fabricated using commercial 3D printing technology and then drawn using a conventional fiber drawing tower. The final PETG fiber outer diameter was 466 µm with a hollow-core diameter of 225 µm. Thermal imaging at the fiber facet performed within the wavelength range 3.5-5 µm clearly indicates air guidance in the fiber hollow-core.

Intercomparison of techniques available at INETI in the analysis of two IAEA candidate research materials.

Under contract with the IAEA, the epiphytic lichen Evernia prunastri was collected to prepare a multielement lichen reference material for quality assurance of environmental studies. An intercomparison run on trace and minor elements in this candidate research material (IAEA-336) was organized in which six analytical groups of the National Institute of Engineering and Industrial Technology (INETI) took part. INAA, PIXE, XRF, AAS, and ICP-ES were applied. The results obtained by different methods are compared, and their complementarity is discussed. As a quality control, the IAEA cabbage research material (IAEA-359) was analyzed. The results agree quite well with the estimated values given by the IAEA.

A randomised, double-blind comparison of three different volumes of hypobaric intrathecal bupivacaine for orthopaedic surgery.

This study was designed to evaluate different doses of hypobaric 0.15% bupivacaine administered to achieve unilateral orthopaedic surgery under subarachnoid block. Using a randomised, double-blinded protocol, 150 ASA I to II patients scheduled for elective unilateral orthopaedic surgery were allocated to received a subarachnoid block with hypobaric bupivacaine 0.15% 4.5 mg (3 ml) (Group 1), 6.0 mg (4 ml) (Group 2) or 7.5 mg (5 ml) (Group 3). Measurements included cardiovascular and haemodynamic stability, incidence of unilateral anaesthesia, time to recover from motor block, postoperative urinary retention, transitory neurological symptoms and postdural puncture headache. There was a dose-dependent increase in the duration of the block, from 1:55 +/- 00:20 hours (4.5 mg) to 2:15 +/- 00:22 hours (6.0 mg) and 3:15 +/- 00:31 hours (7.5 mg). The sensory block in the operated limb was significantly higher than that in the non-operated limb at all times. The increasing dose resulted in an increase of the motor block score. Seventy percent of patients had unilateral block. It was concluded that the spinal anaesthesia in all groups was suitable for single limb orthopaedic surgery. The smallest dose (4.5 mg) of hypobaric 0.15% bupivacaine resulted in more unilateral blocks, with narrower distribution and shorter duration.

[Hypobaric 0.15% bupivacaine versus hyperbaric 0.5% bupivacaine for posterior (dorsal) spinal block in outpatient anorectal surgery.]. / Bupivacaína a 0,15% hipobárica para raquianestesia posterior (dorsal) versus bupivacaína a 0,5% hiperbárica para procedimentos cirúrgicos anorretais em regime ambulatorial.

BACKGROUND AND OBJECTIVES: The aim of this study was to study low dose hypobaric 0.15% bupivacaine and hyperbaric 0.5% bupivacaine in outpatient anorectal surgical procedures. METHODS: Two groups of 50 patients, physical status ASA I and II, undergoing anorectal surgical procedures in a jackknife position, received 6 mg of hypobaric 0.15% bupivacaine in the surgical position (Group 1) or 6 mg of hyperbaric 0.5% bupivacaine in the sitting position for 5 minutes, after which they were placed in a jackknife position (Group 2). Sensitive and motor blockade, time of first urination, ambulation, complications, and the need for analgesics were evaluated. Patients were followed until the third postoperative day and questioned whether they experienced post-puncture headache or temporary neurological symptoms, and until the 30th day and questioned about permanent neurological complications. The test t Student, Mood's median, and Fisher Exact test were used for statistical analysis, and a p < 0.05 was considered significant. RESULTS: Every patient in Group 1 presented selective blockade of the posterior sacral nerve roots, while patients in Group 2 experienced blockade of the anterior and posterior nerve roots. Blockade was significantly higher in Group 1. Motor blockade was significantly less severe in Group 1. Forty-nine patients in Group 1 transferred to the stretcher unassisted while only 40 patients in Group 2 were able to do so. Recovery in Group 1 occurred in 105 +/- 25 minutes and in 95 +/- 15 minutes in Group 2, and this difference was not statistically significant. There were no hemodynamic changes, nausea or vomiting, urine retention, or post-puncture headache. CONCLUSIONS: Anorectal surgical procedures under spinal block with low dose bupivacaine, hyperbaric or hypobaric, can be safely done.

The testes in cadmium intoxication: morphological and vascular aspects.

Cadmium toxicity was tested on young male Wistar rats by injecting 1 mg/ml of cadmium chloride (CdCl2) intra-peritoneally. Post-mortem examination was done 4 hours, 24 hours and 14 days after cadmium administration to observe time-sequence cadmium-induced alterations in vascular permeability of the mesothelium in the pleura, peritoneum and tunica vaginals. This paper mainly reports the alterations observed in the testes. Vascular permeability was assessed by the colloidal carbon technique. Vascular labelling was evidenced as early as 4 hours after CdCl2, injection; 24 hours later severe oedema with leakage of particles to the interstitium and also into the tubules was patent. Fourteen days after CdCl2 administration atrophy of the testes with necrosis of the tubules, fibrosis of the interstitium and vascular thrombosis was found, compatible with chemical castration.

Phlogistic action of ethanol: a study of the vascular response in the gastric and duodenal mucosae.

Ethanol-induced vascular response in the gastric and duodenal mucosae was investigated by light and electron microscopy using the colloidal carbon technique. Investigations were done in fed and starved animals, with a time-response study in each group for 24 hr after ethanol administration. The results show cytoprotection of food against the hazardous effects of ethanol.

[Low isobaric 0.5% bupivacaine doses for unilateral spinal anesthesia.]. / Baixas doses de bupivacaína a 0,5% isobárica para raquianestesia unilateral.

BACKGROUND AND OBJECTIVES: Unilateral spinal anesthesia may be advantageous, especially in the outpatient setting. Low local anesthetic doses, slow spinal injection rate and the lateral position have been related to the easiness of inducing unilateral spinal anesthesia. This study aimed at investigating the possibility of inducing unilateral spinal anesthesia with isobaric 0.5% bupivacaine. METHODS: Spinal anesthesia with 1 mL isobaric 0.5% bupivacaine (5 mg) was induced through 27G Quincke needle in 25 physical status ASA I and II patients undergoing orthopedic procedures. Dural puncture was performed with patients in lateral decubitus with the limb to be operated facing upwards. One mililiter of isobaric bupivacaine was injected in 30 seconds. Sensory and motor blocks were compared between the operated and the contralateral side. RESULTS: Motor and sensory blocks on operated and contralateral sides were significantly different in all studied moments. All patients presented surgical anesthesia in the operated limb. At 20 minutes, nine patients presented sensory block in the contralateral side; at 40 minutes they were 18 and at 60 minutes they were 17 patients. So, unilateral block was present in seven patients (28%) and bilateral block was present in the remaining 18 patients (72%). No patient developed post-dural puncture headache. CONCLUSIONS: Isobaric bupivacaine (5 mg) provides predominant unilateral block after 20 minutes in the lateral position. Isobaric bupivacaine moves in the CSF after 20 minutes resulting in just 28% unilateral blocks. Major advantages of unilateral spinal anesthesia are hemodynamic stability and short duration and it might be a new alternative for outpatient procedures.

The significance of female sex steroids on the vascular permeability of the traumatised uterine serosa of rats.

Using experiments with conjugated hormones, and their influence on vascular permeability assessed by the colloidal carbon technique, we have investigated the effect of female sex steroids on the microcirculation of the uterine horn of virgin rats. We found that oestrogen inhibited vascular permeability in inflammatory conditions. Progesterone increased vascular permeability.

[Unilateral spinal anesthesia with hypobaric bupivacaine.]. / Raquianestesia unilateral com bupivacaína hipobárica.

BACKGROUND AND OBJECTIVES: Restricted sympathetic block during spinal anesthesia may minimize hemodynamic changes. In theory, the use of non-isobaric local anesthetics may induce unilateral anesthesia and limit sympathetic blockade to one side of the body. The local anesthetic dose and the time patients need to remain in the lateral position for achieving unilateral spinal anesthesia are not known. This prospective study investigated the incidence of unilateral spinal anesthesia following injection through a 27G Quincke needle of 0.15% hypobaric bupivacaine, prepared with 1.5 ml standard isobaric bupivacaine plus fentanyl (25 microg), in patients in the lateral position with the limb to be operated upwards. METHODS: Spinal anesthesia with 0.15% bupivacaine + fentanyl (25 microg) was induced through a 27G Quincke needle in 22 ASA I and II patients undergoing orthopedic surgery. Dural puncture was performed with the patient in the lateral position with the side to be operated upwards. After removal of 3 to 5 ml of CSF, 5 ml of the hypobaric bupivacaine-fentanyl mixture were injected at a speed of 1 ml.15 s-1. Sensory and motor block (pinprick/scale 0 to 3) were compared between operated and contralateral sides. RESULTS: Motor and sensory blocks in operated and contralateral sides were significantly different in all moments for both groups. Unilateral spinal anesthesia was obtained in 71% of the patients. No hemodynamic changes were observed in any patient. No patient developed post-dural puncture headache. CONCLUSIONS: Hypobaric 0.15% bupivacaine (7.5 mg) associated to fentanyl provided a predominantly unilateral block after twenty minutes in the lateral position. Major advantages of unilateral spinal anesthesia were hemodynamic stability, patient satisfaction and the absence of post-dural puncture headache.

Low hypobaric bupivacaine doses for unilateral spinal anesthesia.

BACKGROUND AND OBJECTIVES: The possibility to achieve unilateral spinal anesthesia with 0.15% bupivacaine was studied with the purpose of minimizing hemodynamic changes, limiting the cephalad dispersion of the anesthetic and promoting a faster recovery. METHODS: Twenty ASA I - II patients undergoing orthopedic surgeries were given spinal 0.15% hypobaric bupivacaine through a 27G Quincke needle. Dural puncture was performed with patients in the lateral position, with the limb to be operated upwards, and 3.3 ml (5 mg) hypobaric bupivacaine were injected at the rate of 1 ml.15 s(-). Sensory and motor block (pinprick and 0 to 3 scale) were compared between operated and contralateral sides. RESULTS: Motor and sensory block in operated and contralateral sides were significantly different in all evaluated times. Unilateral spinal anesthesia was achieved in 75% of patients. All patients remained hemodynamically stable, and no one developed post-dural puncture headache. CONCLUSIONS: Hypobaric bupivacaine (5 mg) is able to provide a predominant unilateral block with the patient being kept twenty minutes in the lateral position. Major unilateral spinal anesthesia advantage is hemodynamic stability.

Factor for correcting the ruthenium interference in instrumental neutron activation analysis of barium in uraniferous samples.

The fission spectral interference of ruthenium on the instrumental neutron activation analysis of barium in samples containing uranium is extensively discussed. In particular the dependence of the correction factor on the phi epi/phi th ratio is studied. An excellent agreement between experimental and calculated values is achieved. A procedure is suggested for the resolution of multiple interferences in the general case where uranium, barium and/or ruthenium are present in samples to be analysed.