FUNCTIONAL RECONSTRUCTION OF SOFT TISSUE OROFACIAL DEFECTS WITH MICROVASCULAR GRACILIS MUSCLE FLAP.

INTRODUCTION: Free flap reconstructive surgery of middle size and large oral and facial defects enables aesthetic and functional rehabilitation. Microvascular flap reconstructive surgery, with flap survival success rate more than 90-98%, is a gold standard in head and neck extensive reconstructions. Currently, head and neck reconstructive surgery is focused not only on defect occlusion and adequate aesthetical result, but the same emphasize is aimed at functional result. Functional result post tongue and lip resection means defect occlusion with the possibility of movement restoration. Free gracilis muscle flap appears to be a choice for functional tongue and lip reconstruction. MATERIAL AND METHODS: We present 1-year experience with 5 microvascular flap functional reconstructions of middle size and large defects of tongue and lip with free gracilis muscle flap. Four patients post tongue resection and one post subtotal lower lip and cheek resection underwent immediate functional microvascular gracilis muscle flap reconstruction. RESULTS: All five patients were successfully reconstructed with functional free gracilis muscle flap, with no flap loss. We found gracilis muscle flap harvest is not technically demanding, provides adequate tissue volume for middle size orofacial defects reconstruction, with possibility for skin island harvest, and simple primary closure of donor site with very low morbidity. Patients after tongue reconstruction with free gracilis flap were swallowing spoon ood 1 week post operation. Patient after total lip resection and immediate reconstruction with free gracilis flap presented with oral competence before the discharge. The functional result in the group of patients with free gracilis flap reconstruction for orofacial defect will have to be further evaluated again after 2 years post operation considering the ability to swallow and articulate during the speech for the tongue reconstructions and the oral competence and facial mimic for the lip reconstruction. CONCLUSION: Microvascular gracilis muscle flap reconstruction compared to radial forearm flap reconstruction enables functional reconstruction of soft tissue defect. Functional reconstruction of soft tissue defects of tongue or lip with microvascular gracilis muscle flap appears to have advantage of adequate volume, very low donor side morbidity and expectancy of movement renewal compared to other microvascular flap reconstructive options such as anterolateral thigh flap, superficial circumflex iliac artery perforator flap, lateral arm free flap or deep inferior epigastric perforator free flap.

Demonstration of opposing thermal sensitivities in hollow-core fibers with open and sealed ends.

The output phase and propagation time of an optical signal propagating through a hollow-core optical fiber (HCF) drift with changes in environmental temperature significantly less than in conventional optical fibers. In all earlier experimental studies, however, the simplifying assumption was made that the thermo-optic effect of air was negligible. In this Letter, we present, to the best of our knowledge, the first experimental demonstration that the air inside a HCF core can make an appreciable contribution to the fiber's thermal sensitivity with the performance depending on whether the fiber is open to the atmosphere or sealed at both ends (e.g., spliced to solid fiber pigtails). We measure both the sensitivity of the accumulated phase as well as the signal propagation time for both open and sealed HCF and show that these are opposite in sign. Most importantly, we show that the thermal sensitivity contribution from the air inside an open HCF has the sign opposite to the effect of fiber elongation (which is otherwise the dominant effect responsible for the overall thermal sensitivity of HCF). We then go on to show that these two effects can be used to balance each other out in order to achieve zero thermal sensitivity for both accumulated phase and propagation time. We demonstrate this property experimentally over a large spectral range.

Optoelectronic oscillator incorporating hollow-core photonic bandgap fiber.

We demonstrate, to the best of our knowledge, the first optoelectronic oscillator that uses hollow-core photonic bandgap fiber (HC-PBGF) as a delay element of a sufficient length to allow for low-noise operation. We show experimentally that HC-PBGF can improve the temperature stability of the oscillator by a factor of more than 15, as compared to standard optical fiber. We also measured the oscillator's phase noise, allowing evaluation of the suitability of HC-PBGF for this application. Additionally, this Letter also provides, to the best of our knowledge, the first characterization of the temperature stability of a long length (>800 m in our Letter) of low-thermal sensitivity (2 ps/km/K) HC-PBGF wound on a spool.

Demonstration of amplified data transmission at 2 µm in a low-loss wide bandwidth hollow core photonic bandgap fiber.

The first demonstration of a hollow core photonic bandgap fiber (HC-PBGF) suitable for high-rate data transmission in the 2 µm waveband is presented. The fiber has a record low loss for this wavelength region (4.5 dB/km at 1980 nm) and a >150 nm wide surface-mode-free transmission window at the center of the bandgap. Detailed analysis of the optical modes and their propagation along the fiber, carried out using a time-of-flight technique in conjunction with spatially and spectrally resolved (S2) imaging, provides clear evidence that the HC-PBGF can be operated as quasi-single mode even though it supports up to four mode groups. Through the use of a custom built Thulium doped fiber amplifier with gain bandwidth closely matched to the fiber's low loss window, error-free 8 Gbit/s transmission in an optically amplified data channel at 2008 nm over 290 m of 19 cell HC-PBGF is reported.

TRANSCONJUNCTIVAL APPROACH FOR SURGICAL REPAIR OF INFRAORBITAL RIM FRACTURES AND ORBITAL FLOOR FRACTURES.

AIMS: The aim of this study is to retrospectively evaluate the use of a transconjunctival surgical approach in maxillofacial surgery on the fractures of the infraorbital rim and the orbital floor by analyzing the operating time, the incidence of perioperative and postoperative complications, as well as the functional and aesthetic outcomes of transconjunctival surgical treatment. MATERIALS AND METHODS: All the patients on whom we used a transconjunctival approach from December 2017 to December 2021 were included in this retrospective study. The epidemiological causes of fractures of the midface skeleton were analyzed. The length of the operating time of the transconjunctival approach with lateral canthotomy was compared with a control group in which the supraorbital eyebrow approach was performed. In addition, we analyzed the incidence of perioperative and postoperative complications in comparison with publications from other centers. RESULTS: We used the transconjunctival approach 103 times on 89 patients (in 14 patients the transconjunctival approach was performed bilaterally). In cases where the lateral canthotomy was used to extend the transconjunctival approach, there was no prolongation of the operating time. Perioperative complications included the perforation of the lower eyelid in 2 patients. In the postoperative period we recorded complications in 3 patients. Ectropion of the lower eyelid was present in one patient and entropion of the lower eyelid was observed in two patients. The percentage of perioperative and postoperative complications does not exceed the incidence of complications in transcutaneous approaches on the infraorbital rim. CONCLUSION: Based on the results of our study, we can consider the transconjunctival approach, either alone or in combination with lateral canthotomy.

Processing of optical combs with fiber optic parametric amplifiers.

Low noise optical frequency combs consist of equally spaced narrow-linewidth optical tones. They are useful in many applications including, for example, line-by-line pulse shaping, THz generation, and coherent communications. In such applications the comb spacing, extent of spectral coverage, degree of spectral flatness, optical tone power and tone-to-noise ratio represent key considerations. Simultaneously achieving the level of performance required in each of these parameters is often challenging using existing comb generation technologies. Herein we suggest and demonstrate how fiber optic parametric amplifiers can be used to enhance all of these key comb parameters, allowing frequency span multiplication, low noise amplification with simultaneous comb spectrum flattening, and improvement in optical tone-to-noise ratio through various phase insensitive as well as phase sensitive implementations.

Hollow-core fibres for temperature-insensitive fibre optics and its demonstration in an Optoelectronic oscillator.

Many scientific and practical applications require the propagation time through cables to be well defined and known, e.g., an error in the evaluation of signal propagation time in the OPERA experiment in 2011 initially erroneously concluded that Neutrinos are faster than light. In fact, there are many other physical infrastructures such as synchrotrons, particle accelerators, telescope arrays and phase arrayed antennae that also rely on precise time synchronization. Time synchronization is also of importance in new practical applications like autonomous manufacturing (e.g., synchronization of assembly line robots) and upcoming 5G networks. Even when the propagation time through a coaxial cable or optical fibre is carefully calibrated, it is affected by changes in the ambient temperature, posing a serious technological challenge. We show how hollow-core optical fibres can address this issue.

Tunable dispersion-tolerant picosecond flat-top waveform generation using an optical differentiator.

We study the influence of dispersive propagation on picosecond flat-top pulses, which are generated using long period fiber grating (LPG)-based optical differentiators. We suggest an extremely simple scheme to compensate for the dispersion-induced flat-top pulse distortion; this scheme is based on proper tuning the LPG coupling strength. As this coupling strength may be changed via LPG axial straining, the demonstrated device can be tuned to compensate for different levels of the dispersion in a very easy and straightforward fashion. This allows for very fine flat-top pulse shape adjustment, even after propagation through a relatively long section of dispersive optical fiber. In the experimental demonstration reported here, the dispersion tolerance of 1.8-ps flat-top pulses propagating through a standard telecom fiber (SMF-28) was increased from approximately 2 m to approximately 18 m, giving a 9-fold improvement.

Picosecond and sub-picosecond flat-top pulse generation using uniform long-period fiber gratings.

We propose a novel linear filtering scheme based on ultrafast all-optical differentiation for re-shaping of ultrashort pulses generated from a mode-locked laser into flat-top pulses. The technique is demonstrated using simple all-fiber optical filters, more specifically uniform long period fiber gratings (LPGs) operated in transmission. The large bandwidth typical for these fiber filters allows scaling the technique to the sub-picosecond regime. In the experiments reported here, 600-fs and 1.8-ps Gaussian-like optical pulses (@ 1535 nm) have been re-shaped into 1-ps and 3.2-ps flat-top pulses, respectively, using a single 9-cm long uniform LPG.

A miniature fiber optic surface plasmon resonance sensor for fast detection of Staphylococcal enterotoxin B.

A fiber optic surface plasmon resonance (SPR) biosensor for detection of Staphylococcal enterotoxin B (SEB) is reported. The sensor is based on spectral interrogation of surface plasmons in a miniature sensing element based on a side-polished single-mode optical fiber with a thin metal overlayer. For specific detection of SEB, the SPR sensor is functionalized with a covalently crosslinked double-layer of antibodies against SEB. The SPR biosensor is demonstrated to be able to detect ng/ml concentrations of SEB in less than 10 min.

Indomethacin: a review of its cerebral blood flow effects and potential use for controlling intracranial pressure in traumatic brain injury patients.

Traumatic brain injury (TBI) causes about 75,000 deaths and leaves approximately 200,000 people disabled in USA each year. Brain swelling and increased intracranial pressure (ICP) contribute to this morbidity and mortality. Aggressive management protocols, including ICP control, have been shown to reduce the overall mortality from 50% to 36% following severe head injury. Despite these encouraging results, new and improved pharmacologic strategies to control ICP are required. Indomethacin (IND) is a non-steroidal anti-inflammatory agent with unique effects on cerebral blood flow physiology which may be of benefit in reducing elevated ICP in TBI patients. Data from animal models and randomized, controlled studies with pre-term infants have shown that i.v. IND produces rapid, significant reductions in cerebral blood flow (CBF). Controlled studies of i.v. IND in normal volunteers show a reduction in CBF from 26%-40%. Case series involving severe TBI patients suggest that IND i.v. boluses of 30-50 mg reduce ICP by 37%-52%, reduce CBF by 22%-26%, with a modest 14% increase in cerebral perfusion pressure (CPP). Despite these encouraging results, i.v. IND should only be considered an experimental treatment for control of refractory ICP in TBI patients. Larger, well-designed randomized trials in TBI patients will provide more efficacy and safety data and delineate the effects of IND alone or in combination with other proven, effective, or experimental therapies. Once these concerns have been addressed, larger outcome studies will ultimately be needed to determine the role of IND for ICP control in TBI patients.

Active control of long-period fiber-grating-based filters made in erbium-doped optical fibers.

Integrating an active medium with a filtering component can bring new functionalities compared with configurations where the two stages (units) are placed in series. We exploit this phenomenon and demonstrate all-optical tunable filters based on long-period fiber gratings written in an active optical fiber. The tuning is obtained via optical pumping at 980 nm.

Ultrafast all-optical first- and higher-order differentiators based on interferometers.

We demonstrate that a conventional two-arm interferometer can implement first-order temporal differentiation of ultrafast arbitrary optical waveforms. Straightforward extension of this technique to nth-order optical differentiation is also suggested. This approach is experimentally demonstrated by an efficient and accurate first- and second-order temporal differentiation of (sub-)picosecond Gaussian optical pulses.

Interaction between fiber modes and surface plasmon waves: spectral properties.

The interaction between a guided mode of a single-mode optical fiber and a surface plasmon wave supported by a thin metal overlayer is studied. A theoretical description is given of this phenomenon based on the mode expansion and propagation method. It is demonstrated that the interaction can take place only within a narrow wavelength range therefore is manifested by a dip in the spectrum of the transmitted optical power. One can control the wavelength position of the dip by varying the refractive index of the superstate. Experimental study of the realized structure, consisting of a single-mode optical fiber with locally removed cladding and a thin gold overlayer, shows that the 2x10(-3) change in the refractive index of the superstrate shifts the dip by ~10 nm.

Pharmacologic conversion of atrial fibrillation: a systematic review of available evidence.

This report reviews the efficacy of currently available antiarrhythmic agents for conversion of atrial fibrilation (AF) to normal sinus rhythm (NSR). A systematic search of literature in the English language was done on computerized databases, such as MEDLINE, EMBASE, and Current Contents, in reference lists, by manual searching, and in contact with expert informants. Published studies involving humans that described the use of antiarrhythmic therapy for conversion of AF to NSR were considered and only studies that examined the use of agents currently available in the United States were included. Studies exclusively describing antiarrhythmic therapy for conversion of postsurgical AF were excluded. The methodology and results of each trial were assessed and attempts were made to acquire additional information from investigators when needed. Assessment of methodological quality was incorporated into a levels-of-evidence scheme. Eighty-eight trials were included, of which 34 (39%) included a placebo group (level I data). We found in recent-onset AF of less than 7 days, intravenous (i.v.) procainamide, high-dose i.v. or high-dose combination i.v. and oral amiodarone, oral quinidine, oral flecainide, oral propafenone, and high-dose oral amiodarone are more effective than placebo for converting AF to NSR. In recent-onset AF of less than 90 days, i.v. ibutilide is more effective than placebo and i.v. procainamide. In chronic AF, oral dofetilide converts AF to NSR within 72 hours, and oral propafenone and amiodarone are effective after 30 days of therapy. We conclude than for conversion of recent-onset AF of less than 7 days, procainamide may be considered a preferred i.v. agent and propafenone a preferred oral agent. For conversion of recent-onset AF of longer duration (less than 90 days), i.v. ibutilide may be considered a preferred agent. For patients with chronic AF and left ventricular dysfunction, direct current cardioversion is the preferred conversion method. Larger, well-designed randomized controlled trials with clinically important endpoints in specific populations of AF patients are needed.

Trimethoprim/sulfamethoxazole-induced tremor in a patient with AIDS.

OBJECTIVE: To report a case of trimethoprim/sulfamethoxazole (TMP/SMX)-induced tremor responsive to a reduction in dosage. CASE SUMMARY: A 55-year-old white man with AIDS and Pneumocystis carinii pneumonia (PCP) developed a tremor after receiving 5 days of therapy with TMP/SMX 19.4 mg/kg/d (TMP). The tremor resolved completely 3 days after a dosage reduction to TMP/SMX 15.1 mg/kg/d. DISCUSSION: Central nervous system adverse reactions to TMP/SMX have been reported in both the AIDS and non-AIDS populations. To our knowledge, this is the first reported case of TMP/SMX-induced tremor responsive to a reduction in dosage. Pharmacokinetic and clinical data suggest a concentration-dependent etiology for various adverse effects, including tremor. The mechanism of the tremor is unknown; however, toxic metabolites of SMX and disruptions of biogenic amine neurotransmission by TMP have been hypothesized. CONCLUSIONS: TMP/SMX remains the drug of first choice for treating PCP, but it is clearly not well tolerated by patients with AIDS. Concentration-dependent toxicities such as tremor may lead to premature discontinuation of proven, effective TMP/SMX therapy. Using the lower end of the recommended dosing range for TMP/SMX (TMP 15 mg/kg/d) may reduce the incidence of these toxicities while still achieving acceptable TMP concentrations and antimicrobial efficacy.

Meta-analysis of proton pump inhibitors in treatment of bleeding peptic ulcers.

OBJECTIVE: To evaluate the efficacy of proton pump inhibitors (PPIs) compared with placebo and histamine receptor antagonists (H2RAs) for reducing the incidence of rebleeding, surgery, and death in acute gastrointestinal bleeding (GIB) associated with peptic ulcer disease. DATA SOURCES: A systematic search of the English-language literature was performed using MEDLINE, EMBASE, and Pre-MEDLINE (from 1966 to September 2000) and a manual search of references. STUDY SELECTION: Randomized, controlled trials evaluating any PPI for acute GIB in adults with the end points of rebleeding, surgery of death. DATA SYNTHESIS: Nine trials (1829 pts.) were included. The relative odds of rebleeding indicated a 50% reduction in the PPI-treated group (OR 0.50, 95% CI 0.33 to 0.77; p = 0.002, NNTB 9; 95% CI NNTB 6 to 13). The relative odds of surgery indicated a 53% reduction in the PPI-treated group (OR 0.47, 95% CI 0.29 to 0.77; p = 0.003; NNTB 17, 95% CI 12 to 35). The relative odds for mortality indicated a nonsignificant 8% decrease in the odds of death in the PPI-treated group (OR 0.92, 95% CI 0.46 to 1.83, p = 0.81; NNTB 323, 95% CI NNTB 47 to infinity to NNTH 33). CONCLUSIONS: PPIs are superior to H2RAs and placebo in preventing rebleeding and the need for surgery in patients with GIB, although they do not appear to reduce mortality.