Conditioning fecal sludge of public toilets with coupled zero-valent iron and persulfate: Efficiency and mechanism.

This study investigated the efficiency of fecal sludge conditioning using peroxydisulfate (PDS) activated by zero-valent iron (ZVI). For fecal sludge obtained from public toilets in a densely-populated rural area in China, the ZVI/PDS coupling greatly improved its dewaterability as well as the supernatant quality in terms of organic matter and nutrient contents. The capillary suction time (CST) and supernatant turbidity of fecal sludge can be reduced up to 97% and 73% respectively in 10 min by the combination of 0.15 g/g TS ZVI and 0.2 g/g TS PDS. Protein removal, especially for tightly and loosely bound extracellular-polymeric-substance (EPS), is more linearly correlated to CST reduction than polysaccharide removal. Fecal sludge dewatering was improved by the hybrid functions of radical oxidation and iron coagulation. The ZVI/PDS treatment produced larger and looser flocs, probably because 1) surface ionic and hydrophilic groups of fecal sludge were reduced, 2) surface charge was neutralized, and 3) secondary structures of EPS proteins were altered by the radicals. The excellent fecal sludge dewatering was related to strengthened particle hydrophobicity and reduced sludge viscosity and compressibility. The results highlight that the ZVI/PDS combination is potentially an effective conditioning approach for fecal sludge from public toilets.

Enhanced nitrogen removal upon the addition of volatile fatty acids from activated sludge by combining calcium peroxide and low-thermal pretreatments.

This study investigated a combined low-thermal and CaO2 pretreatment to enhance the volatile fatty acid (VFA) production from waste activated sludge (WAS). The fermentative product was added to a sequencing batch reactor (SBR) as an external carbon source to enhance nitrogen removal. The results showed that the combined pretreatment improved WAS solubilization, releasing more biodegradable substrates, such as proteins and polysaccharides, from TB-EPS to LB-EPS and S-EPS. The maximum VFA production of 3529 ± 188 mg COD/L was obtained in the combined pretreatment (0.2 g CaO2/g VS + 70 °C for 60 min), which was 2.1 and 1.4-fold of that obtained from the sole low-thermal pretreatment and the control test, respectively. Consequently, when the fermentative liquid was added as an external denitrification carbon source, the effluent total nitrogen decreased to Class A of the discharge standard for pollutants in rural wastewater treatment plants in most areas of China.

Relative Projective Location of Three Bottom Apexes of Petrous Bone on Skull.

The complex anatomy of petrous part of temporal bone makes the craniotomy around this area challenging. To avoid damaging the interior structures of petrous part of temporal bone, the authors used computed tomography to get the projection of the petrous part of temporal bone on skulls, making the external contours of petrous part clear, thus protecting its interior structure as a reference in craniotomy. The objective of this study was to find out the three-dimensional location of 4 points of petrous part of temporal bone. Parameters of 120 patients (240 observations) between 25 and 65 years who were free of abnormalities and pathological changes in temporal bone were measured on high-resolution spiral multiple slice computed tomographic multiple planar reconstruction images that were parallel to the base plane. The data were analyzed by SPSS, statistical software with the comparison between sides and sexes. The authors found the accurate locations that 4 points of petrous part of temporal bone with mastoidale as the origin. Then the authors connect the 3 vertexes of underside and the petrous apex and lengthen it until intersect with skulls to get the external landmarks. In the end, the authors get the safe range that can be applied to the clinical surgery.

Morphologic Study of Positional Relationship Between Transverse-Sigmoid Sinus and Extracranial Bony Landmarks With Reconstructed Computed Tomographic Image.

OBJECTIVE: By using the line between the lowest point of the mastoid process and the external occipital protuberance as landmarks, to locate the projection of the transverse-sigmoid sinus (TSS) on the skull surface using three-dimensional reconstruction technique, to provide morphological basis for avoiding TSS injuries during surgeries. METHODS: A total of 120 volunteers underwent computed tomography scan, and computed tomography reconstruction was used to reconstruct the 3D model of the skull for structural landmark and measurement. The line between the most prominent point (A) of external occipital protuberance and the lowest point (B) of mastoid process was used as the landmark to depict distance between the TSS sulcus and the landmarks, as well as the width of the TSS sulcus. RESULTS: The widths of the transverse sinus sulcus, denoted as d, at its central landmark J were measured to be significantly different between the right and left sides (t = 6.291, P < 0.05); no statistically significant difference was found in the measurements of indicators including h1, h2, h3, h4, h5, h6, h7, h8, d1, α, s1, s2, s3, s4, s5, s6 between the right and left sides (P > 0.05), or between the males and females (P > 0.05). CONCLUSIONS: These above-mentioned results can help to locate the projection of the TSS sulcus on the skull surface accurately, which is simple and convenient in guiding the surgeons to protect the TSS during surgeries.

Ultrasonic Observation and Clinical Application of Arcade of Struthers in the Mid-Arm.

BACKGROUND: The mid-arm structure named arcade of Struthers has been shrouded in controversy since it was identified. Most specimens in previous studies were European. The occurrence, component, extent, and position of this structure in the xanthoderm are not clear. Moreover, research into the arcade of Struthers has been at the anatomic level and there has been no ultrasonic research. The aim of this study was to elucidate and measure this anatomy by both anatomic dissection and ultrasonic observation to provide clear and definite criteria to classify the arcade of Struthers, as well as operation guidelines for identifying the arcade of Struthers in ultrasonic imaging and surgical decompression. METHODS: Sixty-four upper limb specimens of 32 adult cadavers were dissected. The tendinous arcade of Struthers (TAS) and muscular arcade of Struthers (MAS) were observed and measured, as well as the position at which the medial intermuscular septum was pierced by the ulnar nerve. The position at which the concomitant blood vessel began to accompany the ulnar nerve was also recorded. Twenty healthy adult participants were enrolled for ultrasonic research. The ulnar nerve was scanned from the cubital tunnel to the fossa axillaris for the anatomic structure crossing it. Once the arcade of Struthers was found, the distal and proximal limits were marked on the skin and it was then measured. RESULTS: Anatomic study showed TASs in 21 limbs, and MASs were found in 16 limbs. The total incidence of the arcade of Struthers was 57.8%. The length of TAS (2.12 ± 0.62 cm) and MAS (4.46 ± 1.96 cm) had a significant difference and the distance between its proximal limit and the medial humeral epicondyle were 8.93 ± 1.38 cm and 9.50 ± 1.69 cm, respectively. Ultrasonic study showed that the incidence of the arcade of Struthers was 50.0%. The distance between its proximal limit and the medial humeral epicondyle was 8.52 ± 1.88 cm and 9.45 ± 1.76 cm. The length was 1.85 ± 1.8 cm and 4.23 ± 1.93 cm, respectively. CONCLUSIONS: We believed that an arcade of Struthers described by multiple investigators did exist in Chinese people, and based on our study, it was classified into 2 types: TAS and MAS. Caution should be used to preserve the superior ulnar collateral artery when incising the arcade of Struthers. Ultrasonography can detect the existence ratio, dimension, and location of the arcade of Struthers.

Study on measurements for margin of safety in lateral operation of a transnasoethmoid-sphenoid approach to decompress the optic canal.

OBJECTIVE: The surgical approach through nasal and ethmoid cells to sphenoid sinus is a common clinical method to do the decompression of the optic canal. During this surgery, we can follow landmarks such as ethmoidal arteries. However, when we do the surgery, it is possible to open excessively in lateral operation and damage orbital medial wall. To prevent this from happening, we do a lot of measurements to estimate the distance in lateral operation. We hope to give surgeons some help in clinical use. METHODS: We chose 120 brain imaging findings that showed a normal appearance in our measuring area by means of three-dimensional reconstruction based on high-resolution spiral computed tomography scans. We chose several anatomic landmarks and measured the distances in lateral operation and located a projection point for directing this surgery. RESULTS: The mean values of distance from dacryon and the anterior foramen of the optic canal to the index plane were 5.439 ± 2.4496 and 9.334 ± 2.0628 mm. The mean values of distance from trisection points to the orbital medial wall were 7.359 ± 2.2262 and 6.911 ± 2.3102 mm. The mean value of distance from the projection point to the ipsilateral outer edge of the supraorbital notch was 30.379 ± 5.3676 mm. There are no significant differences for all the distance between the left side and right side. The median of right-side angle between the straight line connecting both sides of the outer edge of supraorbital notch and the straight line connecting the projection point with the ipsilateral outer edge of the supraorbital notch is larger than the left one and has a less variation than the left one. CONCLUSIONS: The lateral distance in surgical operation is consistent among individuals, which can give a safe area to surgeons in lateral operation. The location of the projection point gives surgeons an indication of direction to this surgery.

Optic canal location by computed tomography.

The aim of this study was to provide anatomic data for optic canal decompression. One hundred twenty people (55 males and 65 females) were involved in this study anonymously. Twelve parameters are measured in computed tomography: P1 is the nasal bone tip; P2 is the middle point of tuberculum sellae; P3 is the root of columella nasi; P4 is the cranium end of the optic canal; P5 is the orbit end of the optic canal; P1' is P1's projection on L2; L1 is the line that links P1 and P2; L2 goes through P3 and parallel to L1; L3 is the bisector of right and left and goes through P1. The distance between LI and L2 was 30.47 ± 3.71 mm. The distance between P3 and P1' was 11.66 ± 2.82 mm. The medial canal wall length was 10.64 ± 1.10 mm on the right and 10.51 ± 1.07 mm on the left (P = 0.001). The distance between P1 and P4 was 66.74 ± 5.97 mm. The distance between P1 and P5 was 73.04 ± 6.33 mm on the right and 72.82 ± 6.33 mm on the left (P = 0.004). The distance between P5 and L3 was 6.62 ± 1.33 mm. The distance between P4 and L3 was 12.26 ± 1.63 mm. The distance between P3 and P4 was 75.82 ± 4.63 mm. The distance between P3 and P5 was 82.87 ± 4.60 mm on the right and 82.25 ± 4.86 mm on the left (P = 0.003). The angle between P1P4 and L3 was 12.26 ± 1.63 degrees. The angle between P1P5 and L3 was 5.28 ± 1.13 degrees. The angle between P3P5 and P3P4 was 5.80 ± 0.97 degrees. These results provide a precise location of the optic canal.

Internal carotid artery in endoscopic endonasal transsphenoidal surgery.

The transsphenoidal approach to the pituitary is widely used in pituitary surgery. Even though there are some landmarks for internal carotid artery (ICA) on the wall of the sphenoid sinus, it is not rare to get the artery injured during surgery. We found that the most important landmark, carotid prominence, matched with ICA in merely 37.5% of subjects. In order to find a simple method to locate the artery, we made an anatomical measurement of the ICA and placed the results in a 3-dimensional coordinate system. The sphenoid sinus opening is both the center of the endoscope entry in the anterior sinus wall and the origin of the coordinate system containing 3 orthogonal axes: x, y, and z. The x axis follows the body of the endoscope(out of the sphenoid sinus) parallel to the sagittal plane while z is perpendicular to the sagittal plane. Most of the measurements were obtained in the initial operative plane, which is perpendicular to the sagittal plane and contains the sinus opening and the midpoint of the pituitary fossa. We calculated the coordinates of the midpoint of the pituitary fossa and 4 ICA-related points. The depth of an ICA and the distance between 2 ICAs are also helpful in locating ICA. According to our operation method, all the projective points of the medial edge of ICA on the posterior wall of the sphenoid sinus are lateral to the sphenoid sinus opening, and operating within 0-25 degrees medial to the endoscope body is believed to be safe from ICA injury.