Determination of surface properties and Gutmann's Lewis acidity-basicity parameters of thiourea and melamine polymerized graphitic carbon nitride sheets by inverse gas chromatography.

Melamine and thiourea-derived graphitic carbon nitrides (M-GCN/T-GCN) were synthesized and characterized. The surface properties were investigated using inverse gas chromatography (IGC) and compared. Net retention volumes of M-GCN and T-GCN were measured with n-alkanes (C5-C10) and polar probes. The London dispersive surface free energies (γsd), calculated using Schultz and Dorris-Gray methods, decreased linearly with increasing temperature. The specific components of the enthalpy and entropy of adsorption for the polar probes were obtained using the Schultz, Dong, and Sawyer-Brookman methods. The Gutmann's Lewis acid-base parameters, Ka and Kb, were determined using the surface free energy (ΔGaS) via these methods. The surface character 'S' values (Kb/Ka) of M-GCN and T-GCN using the respective methods are 4.04, 3.78, and 5.08 and 4.11, 5.27, and 2.86. Hence, the surfaces contain more basic than acidic sites and could interact strongly with acidic media. Thus, IGC elucidates the surface charges of the GCN matrix resulting from surface chemical modification.

Noninvasive evaluation of blunt abdominal trauma: prospective study using diagnostic algorithms to minimize nontherapeutic laparotomy.

A prospective study was performed to investigate the feasibility and benefit of evaluating blunt abdominal trauma (BAT) without diagnostic peritoneal lavage (DPL) or other invasive methods. Diagnostic algorithms were designed by using ultrasonography (US) as a screening method. For unstable patients, a free fluid >/= 2 mm thickness on US images over any one of the intraperitoneal spaces (bilateral subphrenic, Morrison, and Douglas pouch) was used as an indicator for laparotomy. For stable patients, any intraabdominal free fluid detected by US was used as an indicator for further investigations. Computed tomography served as a principal complementary method. To further clarify the clinical results, the rate of nontherapeutic laparotomy (NTL) was compared with that from a previous 5-year review done before this study. During studying period of 1 year, 170 patients were consecutively enrolled. There was no delayed diagnosis, and 66 patients were found to have BAT; 17 patients were initial unstable, among whom 15 had free fluid shown by US and 13 patients had confirmed BAT. Eight of the unstable patients with free fluid on US were saved from NTL, of whom six had retroperitoneal hematoma. There was no NTL in unstable patients. Twenty-two patients underwent laparotomy. Two laparotomies done for a suspicion of bowel injury turned out to be NTL. The rate of NTL in the present study was significant lower than that in a previous review (9.1% vs. 32.2%, p = 0.025). Hence following well designed algorithms, noninvasive evaluation of BAT can proceed with safety, and NTL is minimized.

Urgent laparotomy versus emergency craniotomy for multiple trauma with head injury patients.

In blunt multiple trauma (MT) with head injury (HI) patients, it is difficult to decide whether to proceed with immediate laparotomy or craniotomy. In August 1989, abdominal ultrasonography (US) using a simple US scoring system was introduced for MT and HI patients as an initial rapid screening procedure. In MT and HI patients with a US score > or = 3 (n = 14), urgent laparotomy was the procedure of first choice. However, immediate head CT scan, then emergency craniotomy, may be justified in hemodynamically stable MT and HI patients with a US score < 3 (n = 98). Appropriate decision making can be applied to decide which procedure is most exigent.

Blunt gastrointestinal injury in trauma patients.

The evaluation, management, and final outcome of 34 patients with blunt gastrointestinal injury (BGI) were reviewed. Initial absence of symptoms and signs led to two delayed diagnoses. Sonography provided 80% (12/15) positive-predictive value, and three false-negative patients were subsequently detected by diagnostic peritoneal lavage (DPL). Besides repeated clinical surveillance, screening by sonography complemented with DPL provided early detection of blunt bowel injury in trauma patients. In the outcome analysis, BGI patients with high injury-severity scores, intraoperative hypotension, or accompanying major medical diseases were associated significantly with increased risk of infectious complications (P < .05).

Ultrasonography for the evaluation of hemoperitoneum during resuscitation: a simple scoring system.

To assess the need for therapeutic laparotomy in patients with blunt abdominal trauma (BAT), ultrasonography (US) and a simple US scoring system were used to estimate the amount of hemoperitoneum during resuscitation. In group I (BAT with a US score > or = 3), 24 of 25 patients (96%) required therapeutic laparotomy. In group II (BAT with a US score < 3), therapeutic laparotomy was required in only 9 of 24 patients (38%); nonsurgical treatment may be justified in hemodynamically stable patients. Appropriate decisions can be made to perform urgent laparotomy when intra-abdominal bleeding is the culprit in BAT patients. Unnecessary laparotomy can be avoided when the major site of blood loss is not in the abdomen. Ultrasonography, an initial rapid screening procedure in BAT patients, is useful for trauma surgeons in decision making during resuscitation.